WO1999053021A9 - Facteur de differentiation/de proliferation et de conservation des cellules et procedes d'utilisation correspondants - Google Patents

Facteur de differentiation/de proliferation et de conservation des cellules et procedes d'utilisation correspondants

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Publication number
WO1999053021A9
WO1999053021A9 PCT/AU1999/000265 AU9900265W WO9953021A9 WO 1999053021 A9 WO1999053021 A9 WO 1999053021A9 AU 9900265 W AU9900265 W AU 9900265W WO 9953021 A9 WO9953021 A9 WO 9953021A9
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WO
WIPO (PCT)
Prior art keywords
cells
cell
epl
molecular weight
pro
Prior art date
Application number
PCT/AU1999/000265
Other languages
English (en)
Other versions
WO1999053021A1 (fr
Inventor
Michael David Bettess
Peter David Rathjen
Joy Rathjen
Original Assignee
Bresagen Ltd
Michael David Bettess
Peter David Rathjen
Joy Rathjen
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from AUPP2912A external-priority patent/AUPP291298A0/en
Priority claimed from AUPP6097A external-priority patent/AUPP609798A0/en
Application filed by Bresagen Ltd, Michael David Bettess, Peter David Rathjen, Joy Rathjen filed Critical Bresagen Ltd
Priority to NZ507103A priority Critical patent/NZ507103A/xx
Priority to JP2000543569A priority patent/JP2002517982A/ja
Priority to AU33219/99A priority patent/AU755176B2/en
Priority to EP99914359A priority patent/EP1068295A4/fr
Priority to IL13850299A priority patent/IL138502A0/xx
Priority to CA002324591A priority patent/CA2324591A1/fr
Publication of WO1999053021A1 publication Critical patent/WO1999053021A1/fr
Publication of WO1999053021A9 publication Critical patent/WO1999053021A9/fr

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    • C12N15/00—Mutation or genetic engineering; DNA or RNA concerning genetic engineering, vectors, e.g. plasmids, or their isolation, preparation or purification; Use of hosts therefor
    • C12N15/09—Recombinant DNA-technology
    • C12N15/87—Introduction of foreign genetic material using processes not otherwise provided for, e.g. co-transformation
    • C12N15/873—Techniques for producing new embryos, e.g. nuclear transfer, manipulation of totipotent cells or production of chimeric embryos
    • C12N15/877—Techniques for producing new mammalian cloned embryos
    • C12N15/8775—Murine embryos
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07K—PEPTIDES
    • C07K14/00—Peptides having more than 20 amino acids; Gastrins; Somatostatins; Melanotropins; Derivatives thereof
    • C07K14/435—Peptides having more than 20 amino acids; Gastrins; Somatostatins; Melanotropins; Derivatives thereof from animals; from humans
    • C07K14/475—Growth factors; Growth regulators
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07K—PEPTIDES
    • C07K14/00—Peptides having more than 20 amino acids; Gastrins; Somatostatins; Melanotropins; Derivatives thereof
    • C07K14/435—Peptides having more than 20 amino acids; Gastrins; Somatostatins; Melanotropins; Derivatives thereof from animals; from humans
    • C07K14/78—Connective tissue peptides, e.g. collagen, elastin, laminin, fibronectin, vitronectin, cold insoluble globulin [CIG]
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    • C12N5/00—Undifferentiated human, animal or plant cells, e.g. cell lines; Tissues; Cultivation or maintenance thereof; Culture media therefor
    • C12N5/06—Animal cells or tissues; Human cells or tissues
    • C12N5/0602—Vertebrate cells
    • C12N5/0603—Embryonic cells ; Embryoid bodies
    • C12N5/0606—Pluripotent embryonic cells, e.g. embryonic stem cells [ES]
    • A—HUMAN NECESSITIES
    • A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
    • A01K—ANIMAL HUSBANDRY; CARE OF BIRDS, FISHES, INSECTS; FISHING; REARING OR BREEDING ANIMALS, NOT OTHERWISE PROVIDED FOR; NEW BREEDS OF ANIMALS
    • A01K2217/00—Genetically modified animals
    • A01K2217/05—Animals comprising random inserted nucleic acids (transgenic)
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K48/00—Medicinal preparations containing genetic material which is inserted into cells of the living body to treat genetic diseases; Gene therapy
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    • C12N2500/00—Specific components of cell culture medium
    • C12N2500/30—Organic components
    • C12N2500/32—Amino acids
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    • C12N2501/00—Active agents used in cell culture processes, e.g. differentation
    • C12N2501/10—Growth factors
    • C12N2501/113—Acidic fibroblast growth factor (aFGF, FGF-1)
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    • C12N2501/00—Active agents used in cell culture processes, e.g. differentation
    • C12N2501/10—Growth factors
    • C12N2501/115—Basic fibroblast growth factor (bFGF, FGF-2)
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    • C12N2501/00—Active agents used in cell culture processes, e.g. differentation
    • C12N2501/10—Growth factors
    • C12N2501/119—Other fibroblast growth factors, e.g. FGF-4, FGF-8, FGF-10
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    • C12N2501/00—Active agents used in cell culture processes, e.g. differentation
    • C12N2501/10—Growth factors
    • C12N2501/15—Transforming growth factor beta (TGF-β)
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    • C12N2501/00—Active agents used in cell culture processes, e.g. differentation
    • C12N2501/50—Cell markers; Cell surface determinants
    • C12N2501/58—Adhesion molecules, e.g. ICAM, VCAM, CD18 (ligand), CD11 (ligand), CD49 (ligand)
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    • C12N2501/00—Active agents used in cell culture processes, e.g. differentation
    • C12N2501/80—Neurotransmitters; Neurohormones
    • C12N2501/83—Tachykinins, e.g. substance P
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    • C12N2501/00—Active agents used in cell culture processes, e.g. differentation
    • C12N2501/998—Proteins not provided for elsewhere
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    • C12N2502/00—Coculture with; Conditioned medium produced by
    • C12N2502/14—Coculture with; Conditioned medium produced by hepatocytes
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    • C12N2506/00—Differentiation of animal cells from one lineage to another; Differentiation of pluripotent cells
    • C12N2506/02—Differentiation of animal cells from one lineage to another; Differentiation of pluripotent cells from embryonic cells

Definitions

  • the present invention relates to a biologically active factor, and more particularly to a factor capable of influencing differentiation, proliferation and/or maintenance of pluripotent cells including embryonic stem (ES) cells.
  • the present invention also relates to methods of using the biologically active factor to produce from pluripotent cells, pluripotent cells having different properties, more particularly EPL cells; and to methods of producing partially or terminally differentiated cells from the pluripotent cells.
  • the present invention also relates to pluripotent cells and partially or terminally differentiated cells, and their uses.
  • the blastocyst which comprises trophectoderm, primitive endoderm and a pool of pluripotent cells, the inner cell mass (ICM/epiblast).
  • the cells of the ICM/epiblast undergo rapid proliferation, selective apoptosis, differentiation and reorganisation as they develop to form the primitive ectoderm.
  • the cells of the ICM begin to proliferate rapidly around the time of blastocyst implantation.
  • the resulting pluripotent cell mass expands into the blastocoelic cavity. Between 5.0 and 5.5 d.p.c.
  • the inner cells of the epiblast undergo apoptosis to form the proamniotic cavity.
  • the outer, surviving cells, or early primitive ectoderm continue to proliferate and by 6.0-6.5 d.p.c. have formed a pseudo-stratified epithelial layer of pluripotent cells, termed the primitive or embryonic ectoderm.
  • the primitive ectoderm gives rise to the germ cells and, during gastrulation, acts as a substrate for the generation of the primary germ layers of the embryo proper and the extra-embryonic mesoderm.
  • the analysis of developmental potential and differentially expressed genes of temporally distinct pools of pluripotent cells within the pre-gastrulation embryo has identified two distinct populations of pluripotent cells, the ICM and primitive ectoderm. Cells within each population appear homogenous as revealed by transplantation studies and the analysis of gene expression markers. The establishment of pluripotent cell heterogeneity and the determination of sub- populations of pluripotent cells within the primitive ectoderm, as defined by differential gene expression, has not been documented in embryos prior to formation of the primitive streak at 6.5 d.p.c. A paucity of genetic markers and the small size, complexity and relative inaccessibility of the embryo within the uterine environment between 4.5 and 6.5 d.p.c. has not allowed a comprehensive analysis of pluripotent cell progression.
  • Pluripotent cells can be isolated from the preimplantation mouse embryo as embryonic stem (ES) cells.
  • ES cells can be maintained indefinitely as a pluripotent cell population in vitro, and, when reintroduced into a host blastocyst, can contribute to all adult tissues of the mouse including the germ cells.
  • ES cells therefore, retain the ability to respond to all the signals that regulate normal mouse development, and potentially represent a powerful model system for the investigation of mechanisms underlying pluripotent cell biology and differentiation within the early embryo, as well as providing opportunities for embryo manipulation and resultant commercial, medical and agricultural applications.
  • Other pluripotent cells and cell lines will share some or all of these properties and applications.
  • the differentiation of ES cells can be regulated in vitro by the cytokine leukaemia inhibitory factor (LIF) and other gp130 agonists which promote self- renewal and prevent differentiation of the stem cells.
  • LIF cytokine leukaemia inhibitory factor
  • retinoic acid biological molecules that can induce the differentiation of ES cells into specific cell types, in the presence or absence of LIF, are currently unknown.
  • Applicant has identified a biologically active factor which is capable of influencing differentiation, proliferation and/or maintenance of pluripotent cells including ES cells. More specifically, the factor is capable of causing the transition of pluripotent cells (e.g. ES cells in adherant culture and in suspension culture) to pluripotent cells having different properties, more specifically early primitive ectoderm-like (EPL) cells. Additionally the factor is capable of maintaining and supporting proliferation of these cells in vitro. It also allows the isolation and maintenance of EPL cells derived from in vitro and in vivo primitive ectoderm.
  • pluripotent cells e.g. ES cells in adherant culture and in suspension culture
  • EPL early primitive ectoderm-like
  • EPL cells represent an in vitro equivalent of the pluripotent cells of a post implantation embryo prior to 6.0 d.p.c. or early primitive ectoderm.
  • EPL cells refers to cells derived from pluripotent cells that retain pluripotency and are converted to and/or maintained as cells that express Oct4 and Fgf5 by:
  • the pluripotent cells from which the EPL cells may be derived may be but are not restricted to ES cells, in vitro or in vivo derived ICM/epiblast, in vitro or in vivo derived primitive ectoderm, teratocarcinoma cells, EC cells, primordial germ cells, EG cells and pluripotent cells derived by dedifferentiation or by nuclear transfer. EPL cells may also be derived from differentiated cells by dedifferentiation.
  • the EPL cells may be capable of but are not restricted to reversion to ES cells by the removal of (a), (b) or (c) in the presence of a gp130 agonist.
  • the biologically active factor preferably includes two components, a low molecular weight component and a large molecular weight component.
  • the low molecular weight component may be an amino acid or functionally active analogue thereof or a peptide or functionally active fragment or analogue thereof.
  • the low molecular weight component is proline or a functionally active analogue thereof or a peptide including proline or a functionally active fragment or analogue thereof.
  • the low molecular weight component is L-proline or a peptide including L-proline.
  • the peptide preferably has a molecular weight of less than approximately 5 kD, more preferably less than approximately 3 kD.
  • the peptide preferably has a size of approximately 1-11 , more preferably approximately 1-7, most preferably approximately 1-4 amino acids.
  • the peptide is selected from the group consisting of: Pro-ala Ala-pro
  • Substance P free acid arg-Pro-Lys-Pro-Gln-Gln-Phe-Phe-gly-Leu-metOH
  • Protease digested including collagenase digested collagen fragments; and functionally active fragments and analogues thereof; and molecules which compete therewith for biological activity.
  • fragment or analogue is capable of influencing differentiation, proliferation and/or maintenance of pluripotent cells including ES cells.
  • the large molecular weight component may be a polypeptide or protein.
  • the large molecular weight component has a molecular weight of greater than approximately 10 kD, more preferably between approximately 50-1000 kD, most preferably between approximately 100-500 kD.
  • the large molecular weight component may be in solution or contained in an extracellular matrix.
  • the large molecular weight component may be an extracellular matrix protein or functionally active fragment or analogue thereof, for example a fibronectin or laminin or functionally active fragment or analogue thereof.
  • the large molecular weight component is a cellular fibronectin.
  • the cellular fibronectin may have a moiecular weight of approximately 210 to 250 kD, as measured on a 10% reducing/denaturing polyacrylamide gel.
  • compositions capable of influencing differentiation, proliferation and/or maintenance of pluripotent cells including ES cells, said composition including a biologically active factor and/or a low molecular weight component and/or a large molecular weight component as hereinbefore described, together with an adjuvant, diluent or carrier.
  • the biologically active factor may be isolated from a medium conditioned by cultured cells.
  • the components of the biologically active factor may be purified from other sources, synthesised or recombinantly produced. Accordingly, in a further aspect of the present invention there is provided a conditioned medium capable of influencing differentiation, proliferation and/or maintenance of pluripotent cells, or a fraction thereof including medium components below approximately 5 kDa, and/or a fraction thereof including medium components above approximately 10 kDa.
  • the conditioned medium includes a biologically active factor as hereinbefore described or the low or large molecular weight component thereof.
  • the conditioned medium is prepared by a method as hereinafter described.
  • the conditioned medium is prepared using a hepatic or hepatoma cell or cell line, more preferably a human hepatocellular carcinoma cell line such as Hep G2 cells (ATCC HB-8065) or Hepa-1c1c-7 cells (ATCC CRL- 2026), primary embryonic mouse liver cells, primary adult mouse liver cells, or primary chicken liver cells, or an extraembryonic endodermal cell or cell line such as the cell lines END-2 and PYS-2.
  • the biologically active factor may be isolated from a medium conditioned by liver or other cells from any appropriate species, preferably mammalian or avian.
  • the activity may also be derived by contributions from two or more different conditioned media from cells which express one or the other of the components.
  • a method for preparing a conditioned medium capable of influencing differentiation, proliferation and/or maintenance of pluripotent cells including providing cells, and a cell culture medium; culturing the cells in the cell culture medium for a time sufficient to produce the conditioned medium; and separating the cells from the culture medium to provide the conditioned medium.
  • the cells may be of any suitable type.
  • the cells are hepatic or hepatoma cells or a hepatic or hepatoma cell line. More preferably they are selected from the group consisting of a human hepatocellular carcinoma cell line, primary embryonic mouse liver cells, primary adult mouse liver cells and primary chicken liver cells.
  • a human hepatocellular carcinoma cell line such as Hep G2 cells (ATCC HB-8065) or Hepa-1c-1c-7 cells (ATCC CRL-2026) is used.
  • the ceils may be endodermal cells, more preferably primary or cultured extraembryonic cells or cell lines such as the endodermal cell lines END-2 and PYS-2.
  • the cells may be cultured under conditions suitable for their proliferation and maintenance in vitro. This includes the use of serum including fetal calf serum and bovine serum or the medium may be serum-free. Other growth enhancing components such as insulin, transferrin and sodium selenite may be added to improve growth of the cells from which the conditioned medium or extracellular matrix may be derived. As would be readily apparent to a person skilled in the art, the growth enhancing components will be dependent upon the cell types cultured, other growth factors present, attachment factors and amounts of serum present.
  • the cells may be cultured for a time sufficient to establish the cells in culture. By this we mean a time when the cells equilibrate in the culture medium. Preferably the cells are cultured for approximately 3-5 days.
  • the cell culture medium may be any cell culture medium appropriate to sustain the cells employed.
  • the culture medium is preferably DMEM containing high glucose, supplemented with 10% FCS, 40 ⁇ g/ml gentamycin, 1 mM L-glutamine, 37°C, 5% C0 2 .
  • Separation of the cell culture medium from the cells may be achieved by any suitable technique, such as decanting the medium from the cells.
  • the cell culture medium is clarified by centrifugation or filtration (e.g. through a
  • a substantially or partially purified extracellular matrix capable of influencing differentiation, proliferation and/or maintenance of pluripotent cells.
  • the extracellular matrix includes a biologically active factor as hereinbefore described or the large molecular weight component thereof.
  • the extracellular matrix is prepared by a method as hereinafter described.
  • a method for preparing an extracellular matrix capable of influencing differentiation, proliferation, and/or maintenance of pluripotent cells including providing cells, a support substrate, and a cell culture medium; culturing the cells in the cell culture medium in the presence of the support substrate for a time sufficient to produce the extracellular matrix; and separating the cells and the culture medium from the support substrate to provide the extracellular matrix.
  • the cells may be of any suitable type.
  • the cells are hepatic or hepatoma cells or a hepatic or hepatoma cell line. More preferably they are selected from the group consisting of a human hepatocellular carcinoma cell line, primary embryonic mouse liver cells, primary adult mouse liver cells and primary chicken liver cells. Most preferably a human hepatocellular carcinoma cell line such as Hep G2 cells (ATCC HB-8065) or Hepa-1c-1c-7 cells (ATCC CRL-2026) is used.
  • the cells may be endodermal cells, more preferably primary or cultured extraembryonic cells or cell lines such as the endodermal cell lines END-2 and PYS-2.
  • the cells may be cultured as in accordance with the conditions described for preparation of conditioned medium. Isolation of the matrix-associated activity involves separation of the cell culture medium and appropriate cells or cell lines from the ECM and support substratum. This may involve washing the matrix with a suitable buffer. Preferably cells are cultured in 0.2% azide, 0.1 mM PMSF in phosphate buffered saline (PBS) for 6-18 hours to kill and detach cells or cultured in 0.5 mM EGTA for 15 minutes to detach cells, with cells and debris removed by further washes with PBS.
  • PBS phosphate buffered saline
  • an extracellular matrix capable of influencing differentiation, proliferation and/or maintenance of pluripotent cells may be prepared from animal sources such as visceral, parietal or primitive endoderm, or from animal cells and tissues, e.g. placenta.
  • An extracellular matrix may also be prepared by artificial means such as drying down purified or semi purified extracellular matrix components on tissue culture plates.
  • the components of the biologically active factor may be partially or substantially purified. Purification of the components may be carried out by removal of the cells followed by techniques such as cation exchange chromatography, hydrophobic interaction chromatography, anion exchange chromatography, heparin affinity chromatography, size exclusion chromatography, ultraf iltration, normal phase chromatography and/or reverse phase chromatography. Preferably, purification of the components is carried out using FPLC and HPLC chromatographic techniques.
  • the low molecular weight component may be purified by a combination of optional fractionation eg. ultraf iltration, gel filtration chromatography (preferably on a Sepharose G10 column), normal phase chromatography and gel filtration chromatography (preferably on a Superdex peptide gel filtration column); and preferably sequentially in the stated order.
  • optional fractionation eg. ultraf iltration, gel filtration chromatography (preferably on a Sepharose G10 column), normal phase chromatography and gel filtration chromatography (preferably on a Superdex peptide gel filtration column); and preferably sequentially in the stated order.
  • the present invention provides a method for partially or substantially purifying a low molecular weight component of a biologically active factor capable of influencing differentiation, proliferation and/or maintenance of pluripotent cells, said method including providing a source of said low molecular weight component, a first gel filtration chromatography support, a normal phase chromatography support, and a second gel filtration chromatography support; contacting the source of said low molecular weight component with the first gel filtration chromatography support to produce a first fraction; contacting said first fraction with the normal phase chromatography support to produce a second fraction; and contacting said second fraction with the second gel filtration chromatography support to produce the partially or substantially purified low molecular weight component.
  • the method includes the further step of subjecting the source of said low molecular weight component to a fractionation step, e.g. ultrafiltration to obtain a fraction containing components with a molecular weight of less than approximately 3 kD.
  • a fractionation step e.g. ultrafiltration to obtain a fraction containing components with a molecular weight of less than approximately 3 kD.
  • the large molecular weight component may be purified by a combination of affinity chromatography (preferably heparin sepharose affinity chromatography, e.g on a heparin sepharose CL-6B column), anion exchange chromatography (e.g. using a Resource Q anion exchange column) and gel filtration chromatography (preferably on a Superose 6 gel filtration column); and preferably sequentially in the stated order.
  • affinity chromatography preferably heparin sepharose affinity chromatography, e.g on a heparin sepharose CL-6B column
  • anion exchange chromatography e.g. using a Resource Q anion exchange column
  • gel filtration chromatography preferably on a Superose 6 gel filtration column
  • the present invention provides a method for partially or substantially purifying a large molecular weight component of a biologically active factor capable of influencing differentiation, proliferation and/or maintenance of pluripotent cells, said method including providing a source of said large molecular weight component, a heparin affinity chromatography support, an anion exchange chromatography support, and a gel filtration chromatography support; contacting the source of said large molecular weight component with the heparin affinity chromatography support to produce a first fraction; contacting said first fraction with the anion exchange chromatography support to produce a second fraction; and contacting said second fraction with the gel filtration chromatography support to produce the partially or substantially purified large molecular weight component.
  • the large molecular weight component may be purified by a combination of optional fractionation eg ultrafiltration (e.g. using a Amicon DiaFlo YM10 membrane), anion exchange chromatography (e.g. using a Sepharose Q anion exchange column), hydrophobic interaction chromatography (e.g. using a phenyl sepharose hydrophobic interaction column), heparin affinity chromatography (.e.g. heparin sepharose affinity chromatography eg. using a heparin sepharose CL-6B column) and gel filtration (e.g. using a Superose 6 gel filtration column); and preferably sequentially in the stated order.
  • optional fractionation e.g. using a Amicon DiaFlo YM10 membrane
  • anion exchange chromatography e.g. using a Sepharose Q anion exchange column
  • hydrophobic interaction chromatography e.g. using a phenyl sepharose hydrophobic interaction column
  • the present invention provides a method for partially or substantially purifying a large molecular weight component of a biologically active factor capable of influencing differentiation, proliferation and/or maintenance of pluripotent cells, said method including providing a source of said large molecular weight component, an anion exchange chromatography support, a hydrophobic interaction chromatography support, a heparin affinity chromatography support, and a gel filtration chromatography support; contacting the source of said large molecular weight component with the anion exchange chromatography support to produce a first fraction; contacting said first fraction with the hydrophobic interaction chromatography support to produce a second fraction; contacting said second fraction with the heparin affinity chromatography support to produce a third fraction; and contacting said third fraction with the gel filtration chromatography support to produce the partially or substantially purified large molecular weight component.
  • the method includes the further step of subjecting the source of said high molecular weight component to a fractionation step, e.g. ultrafiltration to obtain a fraction containing components with a molecular weight of greater than approximately 10 kD.
  • a fractionation step e.g. ultrafiltration to obtain a fraction containing components with a molecular weight of greater than approximately 10 kD.
  • the large molecular weight component may be purified by gelatin affinity chromatography, preferably gelatin sepharose affinity chromatography, optionally followed by dialysis.
  • the present invention provides a method for partially or substantially purifying a large molecular weight component of a biologically active factor capable of influencing differentiation, proliferation and/or maintenance of pluripotent cells, said method including providing a source of said large molecular weight component, a gelatin affinity chromatography support, and a dialysis system; contacting the source of said large molecular weight component with the gelatin affinity chromatography support to produce a first fraction; and subjecting said first fraction to dialysis to produce the partially or substantially purified large molecular weight component.
  • the methods for purification of the large molecular weight component include the further step of subjecting the source of said large molecular weight component to a fractionation step, e.g. ultrafiltration to obtain a fraction containing components with a molecular weight of greater than approximately 10 kD. This step may be included at any appropriate point in the purification procedure.
  • the source of the large or low molecular weight component is a partially purified biologically active factor as hereinbefore described, a conditioned medium as hereinbefore described or an extracellular matrix as hereinbefore described.
  • a conditioned medium as hereinbefore described may be used to derive and maintain pluripotent cells including EPL cells or the medium may be fractionated to yield the biologically active factor or components thereof, which may be added alone or in combination to other media to provide a pluripotent cell, e.g. EPL cell deriving and maintaining medium.
  • partially or substantially purified or synthetic or recombinent forms of the biologically active factor or components thereof may be added to other media alone or in combination to provide a pluripotent cell, (e.g. EPL cell) deriving and maintaining medium.
  • the conditioned medium may be used undiluted or diluted (e.g. approx. 10-80%).
  • the concentration in the cell maintaining medium is preferably in the range of approximately 40 ⁇ M or greater.
  • the large molecular weight component is cellular fibronectin its concentration in the cell maintaining medium is preferably in the range of approximately 2 ⁇ g/ml or greater.
  • Extracellular matrix from relevant cells and cell lines or extracellular matrix prepared artificially may also be used to provide the large molecular weight component of the biological activity.
  • the conditioned medium, factor or large molecular weight component thereof may also be used to coat culture plates to provide the desired biological activity.
  • the biologically active factor of the present invention or the high or low molecular weight components thereof may be used to produce pluripotent cells including EPL cells, not only from rodents, but also from other more commercially important species including humans.
  • a method of producing and/or maintaining early primitive ectoderm-like (EPL) cells including providing pluripotent cells , and a biologically active factor according to the present invention, or the large or low molecular weight component thereof; or a conditioned medium according to the present invention, or an extracellular matrix according to the present invention and optionally the low molecular weight component of the biologically active factor of the present invention; and contacting the pluripotent cells with the biologically active factor or the large or low molecular weight component thereof, or the conditioned medium, or the extracellular matrix, to produce or maintain the EPL cells.
  • EPL early primitive ectoderm-like
  • the pluripotent cells may be selected from the group consisting of embryonic stem (ES) cells, in vivo or in vitro derived ICM/epiblast, in vivo or in vitro derived primitive ectoderm, primordial germ cells, EG cells, teratocarcinoma cells, EC cells, and pluripotent cells derived by dedifferentiation or by nuclear transfer.
  • EPL cells may also be derived from differentiated cells by dedifferentiation.
  • the biologically active factor or the large or low molecular weight components thereof or the conditioned medium or the extracellular matrix optionally plus low molecular weight component may be used for the isolation, proliferation or maintenance of EPL cells in vitro.
  • EPL cells may be generated in adherent culture or as cell aggregates in suspension culture.
  • the biologically active factor or components of the biologically active factor or the conditioned medium or the extracellular matrix optionally plus low molecular weight component may also be used alone or in combination with other factors to generate differentiated cells, tissues or organs by techniques known to those skilled in the art.
  • the differentiated cells derived from EPL cells may be used in allo, concordant or xenotransplantation, cell therapy, tissue and organ augmentation or replacement, and gene therapy.
  • the pluripotent cells may be contacted with the biologically active factor or the large or low molecular weight component thereof or the conditioned medium or the extracellular matrix optionally plus low molecular weight component in the presence of a gp130 agonist such as the cytokine leukaemia inhibitory factor (LIF) preferably at a concentration of greater than approximately 100 units/ml and more preferably greater than approximately 1000 units/ml.
  • a gp130 agonist such as the cytokine leukaemia inhibitory factor (LIF) preferably at a concentration of greater than approximately 100 units/ml and more preferably greater than approximately 1000 units/ml.
  • LIF cytokine leukaemia inhibitory factor
  • Oncostatin M, CNTF, CT1 or IL6 with the soluble IL6 receptor, and IL11 and other gp130 agonists at equivalent levels may also be used.
  • the pluripotent cells may be ES cells or cells derived from pluripotent cells of ICM/epiblast of embryos or cellular aggregates (embryoid bodies) or primitive ectoderm derived from either embryos or from differentiation in vitro of ES cells as embryoid bodies or cellular aggregates.
  • pluripotent cells may be derived from equivalent cell sources at the stages relevant to each species.
  • the source of pluripotent cells from all species may include cells derived from primordial germ cells or teratocarcinomas.
  • pluripotent cells may be derived by dedifferentiation (e.g. by reverting differentiated cells to a pluripotent state), or by application of nuclear transfer techniques, (e.g.
  • the pluripotent cells may be from any vertebrae including murine, human, bovine, ovine, porcine, caprine, equine and chicken.
  • the cells may be isolated by any method known to the skilled addressee.
  • the method includes the further step of: identifying the EPL cells.
  • the conversion of pluripotent cells to EPL cells may be assessed by expression of marker genes (RNA transcripts and cell surface markers), cell morphology, cytokine responsiveness and/or by differentiation in vitro or in vivo.
  • Marker genes which may be used to assess the conversion of pluripotent cells to EPL cells include known markers such as Rex1, Fgf5, Oct4 alkaline phosphatase, uvomorulin, AFP, H19, Evx1, brachy ⁇ ry, and novel marker genes, identified by the inventors, such as L17, Psc1 and K7. Marker genes down regulated during transition from ES cells to EPL cells include Rex1, L 17 and Psd. Fgf5 and K7 are up regulated during this transition. Pluripotent cell markers Oct4, Alkaline phosphatase and uvomor ⁇ lin are expressed by both ES cells and EPL cells in similar levels. Other genes that are expressed in partially differentiated or differentiated embryonic or extraembryonic lineages such as AFP, H19, Evx1 and brachyury are not expressed in any ES or EPL cells.
  • Cytokines and growth factors which act differently on EPL and other pluripotent cells include members of the FGF family (e.g. aFGF, bFGF and FGF4) which induce differentiation of EPL cells but not ES cells, and the TGF ⁇ family, (e.g. Activin A) which induces differentiation of EPL but not ES cells.
  • FGF family e.g. aFGF, bFGF and FGF4
  • TGF ⁇ family e.g. Activin A
  • EPL cells are maintained in culture by levels of LIF approximately 10 fold lower than required for ES cell maintenance.
  • EPL cell differentiation can be distinguished from that of other pluripotent cells by the rates and proportions of structures and differentiated cell types such as primitive ectoderm, visceral endoderm, nascent mesoderm, cardiac muscle, macrophages and neurons formed within cell aggregates or embryoid bodies.
  • EPL cells undergo accelerated formation of late primitive ectoderm, accelerated and increased formation of nascent mesoderm, beating cardiocytes and macrophages, and decreased or absent formation of visceral endoderm and neurons.
  • EPL cells do not contribute to embryo development following blastocyst injection, whereas ES cells and EG cells do.
  • EPL cells do not contribute to embryo development following blastocyst injection, whereas ES cells and EG cells do.
  • the EPL cells may be maintained in a pluripotent state by culture in the presence of the biologically active factor or components thereof or the conditioned medium or the extracellular matrix optionally plus low molecular weight component, in the presence or absence of additional gp130 agonist until further differentiation, induced by factors, conditions or procedures is initiated.
  • a method of producing partially differentiated and/or terminally differentiated cells including providing pluripotent cells, and a biologically active factor according to the present invention, or the large or low molecular weight component thereof, or a conditioned medium according to the present invention, or an extracellular matrix according to the present invention and optionally the low molecular weight component of the biologically active factor of the present invention; contacting the pluripotent cells with the biologically active factor or the large or low molecular weight component thereof, or the conditioned medium, or the extracellular matrix, in the presence or absence of additional gp130 agonist, to produce early primitive ectoderm-like (EPL) cells; and manipulating the environment of the EPL cells to produce the partially differentiated and/or terminally differentiated cells.
  • EPL early primitive ectoderm-like
  • the pluripotent cells may be selected from the group consisting of embryonic stem (ES) cells, in vivo or in vitro derived ICM/epiblast, in vivo or in vitro derived primitive ectoderm, primordial germ cells, EG cells, teratocarcinoma cells,
  • ES embryonic stem
  • ICM/epiblast in vivo or in vitro derived ICM/epiblast
  • primitive ectoderm primordial germ cells
  • EG cells teratocarcinoma cells
  • EC cells and pluripotent cells derived by dedifferentiation or by nuclear transfer.
  • EPL cells may also be derived from differentiated cells by dedifferentiation.
  • EPL cells may be manipulated by maintenance or removal of the biologically active factor or components thereof or the conditioned medium or the extracellular matrix, in the presence or absence of one or more differentiation agents, e.g. growth factors.
  • one or more differentiation agents e.g. growth factors.
  • maintaining contact of EPL cells with the conditioned medium, biologically active factor, or components thereof, preferably in cell aggregates grown in suspension, preferably in the presence of a growth factor from the FGF family such as FGF4 may be used to produce an at least partially differentiated cell type equivalent to embryonic neurectoderm, which can differentiate further to a range of neural cell types.
  • the neurectoderm is derived via a cell type equivalent to embryonic ectoderm, which can differentiate further to a range of other ectodermal cell types.
  • a growth factor from the TGF- ⁇ family may be added to EPL cells to produce an at least partially differentiated cell type equivalent to embryonic nascent mesoderm, which can differentiate further to a range of mesodermai cell types.
  • embryoid bodies or aggregates formed from pluripotent cells in the presence of conditioned medium, or biologically active factor, or components thereof may be disaggregated to a single cell suspension.
  • conditioned medium or biologically active factor, or components thereof
  • a member of the FGF family eg FGF4
  • these cells differentiate predominantly to an at least partially differentiated cell type equivalent to embryonic nascent mesoderm, which can differentiate further to a range of mesodermai cell types including blood and muscle lineages.
  • the pluripotent cells may be selected from the group consisting of embryonic stem (ES) cells, in vivo or in vitro derived ICM/epiblast, in vivo or in vitro derived primitive ectoderm, primordial germ cells, EG cells, teratocarcinoma cells,
  • ES embryonic stem
  • ICM/epiblast in vivo or in vitro derived ICM/epiblast
  • primitive ectoderm primordial germ cells
  • EG cells teratocarcinoma cells
  • EC cells and pluripotent cells derived by dedifferentiation or by nuclear transfer.
  • EPL cells may also be derived from differentiated cells by dedifferentiation.
  • EPL cell differentiation is achieved by a process of first forming monolayer cultures of EPL cells, and then further culturing the cells in the presence of members of the FGF family or TGF ⁇ family. Cells derived by this process are differentiated cells with distinctive morphologies.
  • EPL cell aggregates in suspension culture in the absence of conditioned medium, or biologically active factor, or components thereof, by aggregation of EPL cells formed in adherent or suspension culture, results in the differentiation of these cells in the absence of cell types, such as visceral endoderm, which are known to influence the differentiation of pluripotent cells in the embryo.
  • Aggregated EPL cells differentiated in this manner form high levels of nascent mesoderm that can be further differentiated to form beating muscle and blood and other tissues of mesodermai origin.
  • the method includes the further step of: identifying the partially or terminally differentiated cells by procedures including cell surface markers and gene expression markers, morphology and differentiation potential.
  • Marker genes which may be used to assess the conversion of pluripotent cells to neurectoderm cells and neural lineages include known markers such as Gbx2, Sox1, Sox2, nestin, N-Cam, Oct4, Fgf5 and brachyury. Markers down regulated during the transition from pluripotent cells to neurectoderm include Oct4 and Fgf5. Markers up regulated during this transition include Gbx2, Sox1, Sox2, nestin and N-Cam. Markers not expressed during this transition include brachyury.
  • Marker genes which may be used to assess the conversion of pluripotent cells to mesoderm and derivatives include known markers such as Oct4, Fgf5 and brachyury and Nkx 2.5
  • Markers down regulated during the transition from pluripotent cells to mesoderm include Oct4 and Fgf5.
  • Markers up regulated during this transition include brachyury and, as the mesoderm differentiates into muscle precursors, Nkx 2.5.
  • Mesoderm and ectoderm germ layer cells can be distinguished on the basis of their differentiation potential in vitro.
  • Mesoderm germ layer can differentiate into muscle and blood lineages but not neurectoderm or neural lineages.
  • Ectoderm germ layer can differentiate into neurectoderm and neural lineages but not muscle and blood lineages.
  • a method for producing predominantly ectodermal germ layer cells for producing from them predominantly partially differentiated ectodermal and neurectodermal cells, and also for producing predominantly terminally differentiated ectodermal cells, including but not restricted to dermal cells, and also for producing predominantly terminally differentiated neuronal cells.
  • mesodermai germ layer cells for producing from them predominantly partially differentiated mesodermai cells, and also for producing predominantly terminally differentiated mesodermai cells, including but not restricted to blood cells and beating cardiocytes.
  • an ectodermal germ layer cell a neurectodermal cell, a partially differentiated ectodermal cell or partially differentiated neurectodermal cell, and a terminally differentiated ectodermal cell, such as a dermal cell, and a terminally differentiated neuronal cell produced by the method of the present invention.
  • a mesodermai germ layer cell a partially differentiated mesodermai cell, and a terminally differentiated mesodermai cell, such as a blood cell and muscle cell produced by the method of the present invention.
  • the EPL cells may be reverted to ES cells by removal of the conditioned medium, or biologically active factor, or components thereof in the presence of a gp130 agonist such as LIF preferably at levels of about 1000 units/ml or greater or other gp130 agonists at equivalent levels.
  • a gp130 agonist such as LIF preferably at levels of about 1000 units/ml or greater or other gp130 agonists at equivalent levels.
  • LIF gp130 agonist
  • This is accompanied by reestablishment of ES cell gene expression, cytokine responsiveness, morphology and differentiation potential, both in vivo and in vitro.
  • This provides means for generating ES cells by reversion or dedifferentiation of primitive ectoderm or EPL cells from any desired species, and particularly from species where ES cells have not been available previously.
  • a method of producing ES cells including providing pluripotent cells, a biologically active factor or large or low molecular weight component thereof according to the present invention, or a conditioned medium according to the invention, or an extracellular matrix according to the invention and optionally the low molecular weight component of the biologically active factor according to the present invention; and a gp130 agonist; contacting the pluripotent cells with the biologically active factor or the large or low molecular weight component thereof, or the conditioned medium, or the extracellular matrix; and in the presence or absence of additional gp130 agonist to produce EPL cells; and contacting the EPL cells with the gp130 agonist in the absence of the biologically active factor or the large or low molecular weight component thereof, or the conditioned medium, or the extracellular matrix; to enable the EPL cells to revert to ES cells.
  • the pluripotent cells may be of any suitable type, as hereinbefore described.
  • the method may include the further step of differentiating the ES cells to produce partially or terminally differentiated cells as hereinbefore described.
  • the gp130 agonist is leukaemia inhibitory factor (LIF).
  • LIF leukaemia inhibitory factor
  • other gp130 agonists such as Oncostatin M, CNTF, CT1 , or IL6 with soluble IL6 receptor at levels required for maintaining pluripotent ES cells in vitro, may also be used.
  • a method of producing genetically modified ES cells including: providing pluripotent cells, a biologically active factor or large or low molecular weight component thereof according to the present invention, or a conditioned medium according to the invention, or an extracellular matrix according to the invention and optionally the low molecular weight component of the biologically active factor according to the present invention; and a gp130 agonist; contacting the pluripotent cells with the biologically active factor or the large or low molecular weight component thereof, or the conditioned medium, or the extracellular matrix in the presence or absence of additional gp130 agonist to produce EPL cells; modifying one or more genes in the EPL cells; and contacting the genetically modified EPL cells with the gp130 agonist in the absence of the biologically active factor or the large or low molecular weight component thereof, or the conditioned medium or the extracellular matrix; to enable the genetically modified EPL cells to revert to genetically modified ES cells.
  • the pluripotent cells may be of any suitable type, as hereinbefore described.
  • genetically modified ES cells may also be produced according to this method, where the reverted ES cells, and not the EPL cells, are genetically modified.
  • the method may include the further step of differentiating the genetically modified ES cells to produce genetically modified partially or terminally differentiated cells by methods as hereinbefore described including formation of EPL cells.
  • genetically modified partially or terminally differentiated cells may be produced by a method which includes providing pluripotent cells, a biologically active factor or large or low molecular weight component thereof according to the present invention, or a conditioned medium according to the invention, or an extracellular matrix according to the invention and optionally the low molecular weight component of the biologically active factor according to the present invention; and a gp130 agonist; contacting the pluripotent cells with the biologically active factor or the large or low molecular weight component thereof, or the conditioned medium, or the extracellular matrix; in the presence or absence of additional gp130 agonist to produce EPL cells; modifying one or more genes in the EPL cells; and differentiating the genetically modified EPL cells to produce the genetically modified partially or terminally differentiated cells.
  • partially or terminally differentiated cells may be produced as hereinbefore described and then genetically modified.
  • the pluripotent cells may be of any suitable type, as hereinbefore described.
  • the present invention also provides a method of producing genetically modified EPL cells, which method includes providing pluripotent cells, and a biologically active factor or large or low molecular weight component thereof according to the present invention, or a conditioned medium according to the invention, or an extracellular matrix according to the invention and optionally the low molecular weight component of the biologically active factor according to the present invention; modifying one or more genes in the pluripotent cells; and contacting the genetically modified pluripotent cells with the biologically active factor or the large or low molecular weight component thereof, or the conditioned medium, or the extracellular matrix; in the presence or absence of additional gp130 agonist to produce the genetically modified EPL cells.
  • the pluripotent cells may be of any suitable type, as hereinbefore described.
  • EPL cells may be produced as hereinbefore described and then genetically modified.
  • the method may include the further step of differentiating the genetically modified EPL cells to produce genetically modified partially or terminally differentiated cells.
  • genetically modified EPL cells and/or ES cells may be produced by dedifferentiating genetically modified partially or terminally differentiated cells by a method including: providing partially or terminally differentiated cells ; and a biologically active factor or large or low molecular weight component thereof according to the present invention, or a conditioned medium according to the invention, or an extracellular matrix according to the present invention and optionally a low molecular weight component of a biologically active factor according to the invention; modifying one or more genes in the partially or terminally differentiated cells; and dedifferentiating the genetically modified partially or terminally differentiated cells, by methods that include contacting the genetically modified dedifferentiated cell with the biologically active factor or the large or low molecular weight component thereof, or the conditioned medium, or the extracellular matrix; in the presence or absence of additional gp130 agonist to produce the genetically modified EPL cells.
  • the genetically modified EPL cells so formed can be reverted to genetically modified ES cells and/or differentiated to form genetically modified partially or terminally differentiated cells as hereinbefore described.
  • genetically modified partially or terminally differentiated cells can be used as karyoplasts in nuclear transfer to form genetically modified dedifferentiated pluripotent cells.
  • the dedifferentiated pluripotent cells so formed can be used to produce genetically modified ES cells and EPL cells by methods that include contact with a biologically active factor or large or iow molecular weight component thereof according to the present invention, or a conditioned medium according to the present invention, or an extracellular matrix according to the present invention and optionally a low molecular weight component of a biologically active factor according to the invention; in the presence or absence of additional gp130 agonist.
  • the genetically modified ES and EPL cells so formed can be differentiated to form genetically modified partially or terminally differentiated cells as hereinbefore described.
  • this method provides a pluripotent cell or genetically modified pluripotent cell which has been maintained in its pluripotent state or a genetically modified partially differentiated cell which has been maintained in its partially differentiated state and which may be used to form chimeric animals and transgenic animals, including animals generated by nuclear transfer.
  • ES cells genetically modified ES cells, EPL cells, genetically modified EPL cells, partially or terminally differentiated cells and genetically modified partially or terminally differentiated cells produced by the methods of the present invention.
  • a method of producing a chimeric animal including providing a pluripotent cell or a genetically modified pluripotent cell according to the present invention, and a pregastrulation embryo; introducing the pluripotent cell or genetically modified pluripotent cell into the pregastrulation embryo; and monitoring chimera forming ability.
  • a chimaeric or transgenic animal including animals derived by nuclear transfer, produced using a cell or genetically modified cell according to the present invention.
  • the biologically active factor, components thereof, conditioned medium, extracellular matrix, cells and methods of the present invention have a number of applications, including the following:
  • EPL cells of any origin and cells derived from EPL cells (ES cells, partially differentiated cells, terminally differentiated cells) may be used as cytoplasts or karyoplasts in nuclear transfer.
  • Genetically modified ES cells, genetically modified EPL cells, and genetically modified partially differentiated and genetically modified terminally differentiated cells may be used as cytoplasts or karyoplasts nuclear transfer.
  • EPL cells derived by dedifferentiation of partially differentiated cells or terminally differentiated cells may be used as source of nuclear material for nuclear transfer.
  • Genetically modified EPL cells derived by dedifferentiation of genetically modified partially differentiated cells or genetically modified terminally differentiated cells may be used as source of nuclear material for nuclear transfer.
  • Unmodified or genetically modified pluripotent cells, partially differentiated cells, terminally differentiated cells, tissues, organs and animals may be derived by nuclear transfer when EPL cells are used as cytoplasts or karyoplasts.
  • EPL cells obtained from any source, and preferably their differentiated progeny obtained by programmed or directed differentiation may be used in unmodified form for human cell therapy.
  • the preferred mode of use is to use autologously-derived EPL cells and their progeny.
  • Cells programmed to form ectodermal lineages can be used for cell therapy procedures including but not restricted to neuronal and dermal cell therapy procedures.
  • cell therapy using neuronal cells can be used to treat Parkinson's disease.
  • Cells programmed for mesodermai lineages can be used for cell therapy procedures including but not restricted to bone marrow and muscle cell therapies; for example, for the treatment of cancer and for bone marrow rescue.
  • EPL cells obtained by any means described in this application and preferably their differentiated progeny obtained by directed or programmed differentiation may be used for human gene therapy.
  • Such gene therapy would preferably be conducted using autologously-derived EPL cells or their differentiated progeny.
  • genetic diseases include but are not restricted to haemophilia, diabetes type 1 , Ducheynne's and other muscular dystrophies, Gauche's disease and other mucopolysaccharide diseases, cystic fibrosis.
  • EPL cells obtained from any source, and preferably their differentiated progeny obtained by programmed or directed differentiation may be genetically modified to render them resistant to viral infection by genetic manipulation of for example viral receptors to provide cells conferring resistance to infection by that virus.
  • EPL cells obtained from any source, and preferably their differentiated progeny obtained by programmed or directed differentiation may be genetically modified to allow the cells to act as drug delivery systems for biologically active protein drugs such as cytokines or lymphokines for example interleukin-2 for treatment of cancers and other diseases.
  • Unmodified or genetically modified EPL cells obtained from any source, and preferably their differentiated progeny obtained by programmed or directed differentiation may be used to generate cells and tissues and components of organs for transplant.
  • MEDII effects the transition of ES cells to EPL cells.
  • ES cells cultured in the presence of MEDII show a characteristic morphology associated with the formation of EPL cells. The bar indicates 50 ⁇ m.
  • D ES cells were seeded at a density of 250 cells/cm 2 in DMEM containing LIF, 50% MEDII+LIF, 50% MEDII and without addition. After 5 days the cultures were stained for alkaline phosphatase and haematoxylin, and the percentage of ES, EPL and differentiated colonies determined.
  • Alkaline phosphatase positive colonies were subdivided into ES and EPL cell colonies on the basis of morphology, differentiated colonies (D) were determined as alkaline phosphatase negative.
  • Plating efficiencies (%) for each condition were 42.8 +/- 8.7 (LIF); 47.26 +/- 2.6 (50% MEDII+LIF); 40.5 +/- 5.9 (50% MEDII); 41.4 +/- 6.6 (no addition).
  • FIG. 1 A Northern blot analysis of ES and EPL cell RNA. 20 ⁇ g of total RNA, isolated from E14 ES cells, EPL cell derivatives cultured in MEDII or MEDII+LIF for 2, 4, 6, and 16 days (i), and spontaneously differentiated ES cells cultured for 6 days in the absence of exogenous factors (ii), was analysed for the expression of Fgf5, Rex1, Oct4, and mGAP.
  • Fgf5 transcripts were 2.7 and 1.8 kb (Hebert et al., 1990), Rex1 1.9 kb (Hosier et al., 1989), Oct4 1.55 kb (Rosner et al., 1990) and mGAP 1.5 kb.
  • FIG. 1 Northern analysis of L17 (A), Psd (B) and K7 (C) expression in 5 ⁇ g of poly A RNA (L17 and Psd) or 20 ⁇ g total RNA (K7) isolated from ES cells and EPL cells, maintained in culture in MEDII + LIF for up to 8 days. Transcript sizes are indicated in the figure. Northern blots were quantified and normalised to the expression of Oct4.
  • Figure 5 In vivo expression of novel marker genes, L17 ( ), Psd (B) and K7 (C) by wholemount in situ hybridisation analysis of mouse embryos dissected between 3.5 d.p.c. and 5.5 d.p.c. PE - primitive ectoderm; PC - proamnionic cavity; VE - visceral endoderm.
  • hLIF is required for the maintenance of EPL cells in culture.
  • ES cells were seeded at a density of 250 cells/cm 2 into DMEM containing 50% MEDII or 50% MEDII+mLIF (1000 units/ml), hLIF (1000 units/ml), anti-hLIF antibodies (10 ⁇ g/ml), hLIF (1000 units/ml) and anti-hLIF antibodies (10 ⁇ g/ml), mLIF (1000 units/ml) and anti-hLIF antibodies (10 ⁇ g/ml), anti-gp130 antibodies (10 ⁇ g/ml) or hLIF (1000 units/ml) and anti-gp130 antibodies (10 ⁇ g/ml).
  • DMEM:MEDII EBMs, ii, iv, vi
  • Oct4 i, ii
  • brachyury iii, iv
  • Fgf5 v, vi
  • Fgf5 transcripts were 2.7 and 1.8 kb (Hebert et al., 1990), brachyury 2.1 kb (Lake, 1996), Oct4 1.55 kb (Rosner et al., 1990) and mGAP 1.5 kb.
  • FIG. 9 (A) Northern blot analysis of EPL cells and reverted EPL cells. 20 ⁇ g of total RNA from EPL cells, cultured in the presence of MEDII or MEDII+LIF for 2, 4 and 6 days, and their reverted derivatives, reverted in medium containing LIF alone (2 R , 4 R and 6 R ), was analysed by Northern blot for the expression of Fgf5, Rex1, Oct4 and mGAP. (B) Clonal EPL cell lines #1 and #2 were seeded at a density of 250 cells/cm 2 and 500 cells/cm 2 respectively into medium containing mLIF and 50% MEDII + LIF.
  • EBs on days 1 , 2, 3 and 4 of development was analysed for the expression of Rex1, Fgf5, Oct4 and mGAP by northern blot analysis.
  • B The number of alkaline phosphatase positive pluripotent cell colonies derived from culture of single cell suspensions of day 5, 6, 7 and 8 EBs in DMEM supplemented with LIF (grey) or DMEM supplemented with LIF + 50% MEDII (black).
  • A Morphology of 5.5 d.p.c. embryo explants cultured for 5 days in embryo culture medium (LIF/CIV) or embryo culture medium + 50% MEDII (MEDII/CIV).
  • FIG. 12 (A) Schematic representation of the strategy used for isolation and maintenance of pluripotent cells from the primitive ectoderm of the mouse embryo. (B) Embryonic explants representative of different stages of the isolation procedure. Explants from several different isolation experiments are shown.
  • sfMEDII Two soluble factors within MEDII are responsible for the formation of EPL cells from ES cells.
  • sfMEDII was separated via ultrafiltration on a centricon-3 unit into a retained fraction (R) and an eluted fraction (E).
  • ES cells were seeded at a density of 250 cell/cm 2 into medium containing E, R or E + R in the presence of LIF. After 5 days the cultures were stained for alkaline phosphatase and the percentage of ES, EPL (alkaline phosphatase positive) and differentiated colonies (alkaline phosphatase negative; D) was determined.
  • Plating efficiencies were 48.4% (eluted fraction); 41.6% (retained fraction); 49.2% (eluted and retained fractions); 32.8% (mLIF).
  • FIG. 15 Purification of the low molecular weight component of the EPL cell-inducing activity.
  • A Fractionation of E by Sephadex G10 gel filtration.
  • B Fractionation of active fractions from A by normal phase chromatography.
  • C Fractionation of active fractions from B by Superdex peptide gel filtration. Eluted material was detected by absorbance at 215 nm. Chromatographic fractions were assayed for the presence of the low molecular weight component of the EPL cell- inducing activity. Solid lines beneath each chromatogram indicate fractions containing this activity.
  • FIG. 20 Western blot of purified human plasma fibronectin (1 ⁇ g, 0.5 ⁇ g), human cellular fibronectin (1.0, 0.5, 0.25 ⁇ g) and the large molecular weight component of sfMEDII purified by protocol 2 (1.0, 0.5, 0.25 ⁇ g) probed with a monoclonal antibody (3E2, Sigma) directed against human cellular fibronectin. The positions of protein size markers are indicated.
  • FIG. 21 Components of the EPL cell-inducing activity can be identified in divergent cell types and species.
  • A Morphology of ES cells seeded into DMEM + 50% conditioned medium from primary adult mouse or embryonic chick hepatocytes after 3 days in culture.
  • B Morphology of ES cells seeded into DMEM + 50% conditioned medium from Hepa-1c1c 7 cells +/- 40 ⁇ M L-proline, or DMEM + 50% conditioned medium from END-2 cells +/- 10 ⁇ g cellular fibronectin.
  • Figure 22 Morphology of ES and EPL cell EBs at day 4 of differentiation.
  • A ES EBs
  • B EPL EBs.
  • C, D EBs were sectioned and stained with toluidine-blue;
  • C ES EB,
  • D EPL EB.
  • FIG. 23 Expression of the pluripotent cell markers Fgf5, Rex and Oct4 in differentiating ES and EPL cell EBs.
  • Northern blot analysis was carried out on 20 ⁇ g total RNA from ES and EPL cell EBs at indicated days of differentiation.
  • Expression of mGAP was used as a loading control.
  • FIG. 24 EPL cells form parietal endoderm but not visceral endoderm when differentiated as EBs.
  • A Expression of SPARC in EBs derived from ES and EPL cells at days 1-4 of differentiation as determined by northern blot analysis on 20 ⁇ g total RNA.
  • B,C Sections of day 4 ES (B) and EPL (C) cell EBs subjected to wholemount in situ hybridisation with antisense DIG-labelled SPAftC-specific riboprobes.
  • D,E Wholemount in situ hybridisation of day 4 ES (D, F) and EPL (E) cell EBs with antisense DIG-labelled / FP-specific riboprobes. Areas expressing AFP are indicated with arrows.
  • F Cross section of an ES cell EB stained for AFP relax,- oo expression.
  • FIG. 25 EPL cells regain the ability to form visceral endoderm when mixed with ES cells during EB formation.
  • Figure 26 Enhanced and accelerated mesoderm induction in EPL cell EBs compared to ES cell EBs.
  • A Expression of brachyury, goosecoid and mGAP in ES and EPL cell EBs at day 0-4 of differentiation as determined by Northern blot analysis on 20 ⁇ g total RNA.
  • B-l Wholemount in situ hybridisation of ES (B,D,F,H) and EPL (C,E,G,I) cell EBs with antisense DIG-labelled riboprobes specific for brachyury (B-E) and Oct4 (F-1) at day 3 (B.C.F.G) and day 4 (D,E,H,I).
  • Figure 27 Enhanced and accelerated formation of beating cardiocytes in EPL cell EBs compared to ES cell EBs.
  • B Nkx2.5 expression in ES and EPL cell EBs at day 4-12 as determined by Northern blot analysis on 20 ⁇ g total RNA.
  • FIG. 28 The ability of EPL cells to form neurons depends on the in vitro differentiation regime employed.
  • A Percentages of ES and EPL cell EBs forming neurons on days 8, 10 and 12 of differentiation.
  • FIG. 29 Differentiation of ES and EPL cells in response to growth factors of the FGF and TGF ⁇ families.
  • A An EPL cell colony, differentiated in the presence of bFGF, showing the characteristic differentiated morphology of cell type A.
  • B The proportions of ES cell (ES), EPL cell (EPL), differentiated cell (D) and mixed EPL and differentiated cell (SD) colonies after culture of ES and EPL cells in the presence or absence of bFGF (10 ng/ml) after 5 days.
  • C An EPL cell colony, differentiated in the presence of activin A, showing the characteristic differentiated morphology of cell type B.
  • ES ES
  • EPL EPL
  • differentiated cell D
  • SD mixed EPL and differentiated cell
  • FIG. 30 Reverted EPL cells have a differentiation potential similar to ES cells when differentiated as EBs.
  • A Northern analysis on 20 ⁇ g total RNA of Fgf5 and brachyury expression in EBs derived from ES, EPL and EPL R cells at days 1-4 of differentiation.
  • FIG. 31 Directed formation of pluripotent cells to neurectoderm via formation of EBMs.
  • A EBMs formed from ES cells and grown for 4 days in DMEM + 50% MEDII and a further 3 days in DMEM + 50% MEDII + 20ng/ml FGF4. Distinctive convoluted cell layers of pseudostratified epithelial appearance are formed within the aggregate.
  • B Aggregates grown as for A were seeded onto gelatin treated plastic for 16 hours in DMEM + 50% MEDII + 20 ng/ml FGF4 and analysed for the expression of Oct4 (i), brachyury (ii), Gbx2 (iii) and Sox1 (iv) by in situ hybridisation.
  • FIG 32 Expression of neurectoderm and neural stem cell markers in aggregates derived from EBMs.
  • EBMs day 4 were cultured for 3 days in DMEM + 50% MEDII + 20 ng/ml FGF4 and seeded onto gelatin for analysis of gene expression at days 8, 9 and 10.
  • A In situ hybridisation of aggregates with Gbx2, Sox1 and Sox2 antisense probes.
  • B Immunohistochemistry of aggregates on day 9 with antibodies directed against nestin and N-Cam.
  • Figure 33 Expression of pluripotent cell and neurectoderm markers during programmed formation of neurectoderm from EBMs.
  • A 10 ⁇ g total RNA from ES cell EBs (IC+B, day 4), ES cell EBs cultured from day 4 in DMEM + 20 ng/ml
  • FGF4 (IC+B/FGF, days 5-8), EBMs (MEDII, day 4), and EBMs cultured from day 4 in DMEM + 50% MEDII + 20 ng/ml FGF4 (MEDII/FGF, days 5-8) was analysed for expression of Oct4, Fgf5 and mGAP by northern blot.
  • B RNase protection for Gbx2 and Sox1 on 20 ⁇ g total RNA from EBMs (day 4) and EBMs cultured in DMEM + 50% MEDII + 20 ng/ml FGF4 (days 6, 7, 8).
  • Figure 34 Formation of differentiated cell types of mesoderm and ectoderm origin by directed differentiation of pluripotent cells in vitro. Individually seeded aggregates developed from ES cell EBs (control EB) and EBMs (EBM) were scored on days 8, 10 and 12 for the presence of (A) beating cardiocytes
  • FIG 35 The large molecular weight component of MEDII promotes formation of neurons from EPL cells. Individually seeded aggregates developed from EPL cell EBs cultured in 1 , and 4, DMEM; 2 and 5, DMEM + anti-human LIF antibody; 3 and 6, DMEM+ anti-human LIF antibody + 100 ⁇ g/ml R were assessed on days 7, 8, 9 and 10 for the presence of beating cardiocytes (1 , 2, 3) and neurons (4, 5, 6).
  • FIG. 36 Formation of mesoderm by reaggregation of EPL cells formed in suspension. 20 ⁇ g total RNA from EBMs (day4) which had been trypsinised to single cells and reaggregated in DMEM (IC+B) +/- 10 ng/ml FGF4, or DMEM + 50% MEDII (MEDII) +/- 10 ng/ml FGF4 was analysed after 2 and 4 days for expression of brachyury and Oct4 by northern blot. Representative aggregates in DMEM and DMEM + 50% MEDII at day 4 are shown.
  • FIG. 37 Nascent mesoderm in EPL cell EBs can be programmed to formation of haemopoietic cells.
  • ES and EPL cell EBs were cultured in methylcellulose supplemented with IL-3 and M-CSF to induce formation of macrophages.
  • the proportion of aggregates containing macrophages was determined on days 12, 15 and 18.
  • FIG 38 Comparative analysis of methodologies for directed formation of mesoderm (EPL EBs) and ectoderm (EBM) germ layers from pluripotent cells. Seeded aggregates were scored at day 10 for formation of beating cardiocytes and day 12 for formation of neurons.
  • Table 1 Summary of the gene expression patterns of ES cells and EPL cells compared to gene expression in the ICM and primitive ectoderm of the embryo. RNA was isolated from ES cells and EPL cells grown in the presence of MEDII for 2 days and analysed by Northern blot for the expression of Oct4, uvomorulin, Fgf5, Rex1, AFP, H19, Evx1 and Brachyury. Gbx2 expression was detected using RNA protection assays.
  • Alkaline phosphatase activity was detected using an enzymatic stain on ES and EPL cell layers.
  • Embryonic expression patterns were determined by Rosner et al., 1990, Schler et al., 1990, Yeom et al., 1991 (Oct4); Hahnel et al., 1990 (alkaline phosphatase); Sefton et al., 1992 (uvomorulin); Haub and Goldfarb, 1991 Hebert et al., (Fgf5); Rogers et al., 1991 (Rex1); Bulfone et al., 1993; Chapman et a!., 1997 (Gbx2); Dziadek and Adamson, 1978 (AFP); Poirier et al., 1991 (H19); Bastian and Gruss, 1990, Dush and Martin, 1992 (Evx1); and Herrmann, 1991 (Brachyury).
  • EPL E14TG2a ES cells
  • EPL EPL cell derivatives grown in 50% MEDII for 2 and 4 days
  • EPL EPL cell derivatives grown in 50% MEDII for 6 days
  • ECM components were seeded onto tissue culture plastic pretreated with the ECM components gelatin, laminin, plasma fibronectin, collagen IV and a mix of laminin, plasma fibronectin and collagen IV in DMEM + 50% MEDII. After 5 days cultures were stained for alkaline phosphatase and the percentages of EPL cell colonies with no associated differentiation were determined.
  • ECM components were presented to ES cells in solution (+/- 40 ⁇ M L-proline), or as matrices (+/- 40 ⁇ M L-proline).
  • ECM components were used in solution at 10 ⁇ g/ml (collagen IV; vitronectin and plasma fibronectin) 3 ⁇ g/ml (Laminin) or 2 ⁇ g/ml (cellular fibronectin and purified bioactivity). Gelatin was used at 0.01% and MEDII at 50%.
  • EPL cells from ES cells in response to biologically derived factors
  • ES cells were cultured in the absence of feeders on tissue-culture grade plastic-ware (Falcon) pre-treated with 0.2% gelatin/PBS for a minimum of 30 minutes. Ceils were cultured in Dulbecco's Modified Eagles Medium (Gibco BRL), pH 7.4, containing high glucose and supplemented with 10% foetal calf serum (FCS; Commonwealth Serum Laboratories), 40 ⁇ g/ml gentamycin, 1 mM L-glutamine, 0.1 mM ⁇ -mercaptoethanol ( ⁇ -ME), herein referred to as DMEM, supplemented with 1000 units of LIF under 10% C0 2 in a humidified incubator. Routine tissue culture was performed as described by Smith (1991).
  • E14 ES cells (Hooper et al., 1987) were obtained from Anna Michelska (Murdoch Institute, Melbourne). CCE ES cells (Robertson et al., 1986) were obtained from Richard Harvey (Walter and Eliza Hall Institute, Melbourne). MBL5 (Pease at al., 1990) and D3 (Doetschman et al., 1985) ES cell lines were obtained from Lindsay Williams (Ludwig Institute, Melbourne). CGR8 and E14TG2a (Hooper et al., 1987) ES cells were provided by Austin Smith (Centre for Genome Research, Edinburgh).
  • LIF was produced from COS-1 (ATCC CRL-1650) cells transfected with a mouse LIF expression plasmid, pDR10, as described by Smith (1991 ) with the following modifications.
  • COS-1 cells were transfected by electroporation using a Bio-rad Gene Pulsar at 270 Volts and a capacitance of 250 ⁇ FD.
  • Transfected cells were plated at 7x10 4 cells/cm 2 in DMEM, pH 7.4, containing high glucose and supplemented with 10% FCS, 40 ⁇ g/ml gentamycin and 1 mM L-glutamine.
  • Medium was collected and assayed for LIF expression as described by Smith (1991). Alternatively, medium was supplemented with 1000 units of recombinant LIF (ESGRO, AMRAD).
  • Hep G2 cells (Knowles et al., 1980; ATCC HB-8065) were maintained in culture in DMEM and passaged at confluence.
  • To condition medium (MEDII) Hep G2 cells were seeded into DMEM at a density of 5 x 10 4 cells/cm 2 . Medium was collected after 4-5 days, sterilised by filtration through a 0.22 ⁇ m membrane and supplemented with 0.1 mM ⁇ -ME before use. MEDII was stored at 4°C for 1-2 weeks or at -20°C for up to 6 months without apparent loss of activity.
  • EPL cells were formed and maintained in media containing 50% MEDII conditioned medium in DMEM with or without the addition of LIF. EPL formation was apparent with the addition of between 10 and 80% MEDII, with optimal culture conditions at 50% MEDII (data not shown). EPL cells were formed from ES cells and maintained as follows :-
  • Adherent culture ES cells were seeded at a density of 1.3 x 10 4 cells/cm 2 onto tissue-culture grade plastic-ware (Falcon) pre-treated with 0.2% gelatin/PBS for a minimum of 30 minutes in DMEM containing 50% MEDII as described above. EPL cells were maintained in 50% MEDII using routine tissue culture techniques
  • ES cells were seeded at a density of 1 x 10 5 cells/cm 2 in suspension culture in bacterial petri dishes in DMEM containing 50% MEDII as described above. The resulting EPL cell aggregates were split 1 :2 after 2 days and seeded into fresh DMEM containing 50% MEDII. Control aggregates (EBs) were formed by aggregating ES cells in identical fashion in DMEM without MEDII.
  • Nucleic acids were resuspended in 400 ⁇ l DNase I buffer (50 mM Tris.CI, pH 8.0; 1 mM EDTA, pH 8.0; 10 mM MgCI 2 ; 0.1 mM DTT), 20 units of RNase free DNase I (Boehringer Mannheim) and incubated for one hour at 37°C. RNA was precipitated by the addition of 40 ⁇ l 3M NaAcetate and 1 ml ethanol and collected by centrifugation.
  • DNase I buffer 50 mM Tris.CI, pH 8.0; 1 mM EDTA, pH 8.0; 10 mM MgCI 2 ; 0.1 mM DTT
  • RNase free DNase I Boehringer Mannheim
  • a Brachyury specif ic probe was excised from pSK75 (Herrman, 1991) as a 1600 bp EcoRI fragment.
  • An uvomorulin probe was excised from F20A in pUC8 (Ringwald et al., 1987) as a 620 bp EcoRI fragment.
  • a 700 bp Psfl/BamM Evx1 cDNA fragment was excised from pAB11 (Dush and Martin, 1992).
  • Fgf5 was obtained as a full length coding region clone in Bluescript (Hebert et al., 1990), from which an 800 bp EcoRI/EamHI cDNA fragment was isolated and used as a probe.
  • An AFP probe was generated from a 400 bp EcoRI fragment encoding the first 350 bp of the mouse AFP cDNA cloned into in pBluescript KS 11+ (courtesy of Dr. R. Krumlauf, NIMR, London).
  • An 848 bp Rex1 fragment, cloned into pCRTMll (pRexl , obtained from Dr. N. Clarke, Department of Genetics, Cambridge University, U.K.) was excised by EcoRI digestion.
  • a mGAP probe was synthesised by labelling a whole plasmid containing 300 bp of mGAP cDNA sequence (Rathjen at al., 1990).
  • the 737 bp, 232 bp and 458 bp ddPCR fragments of L17, K7 and Psd respectively were released from Bluescript II KS + by EcoRI digest and used as probes.
  • Anti-sense Oct4 probes were synthesised by T3 RNA polymerase as run-off transcripts from bluescript containing a 462 bp Stu ⁇ Oct4 cDNA fragment (Scholer et al., 1990), linearised with Hinc ⁇ U.
  • Sense transcripts, used as controls, were obtained from the same plasmid linearised with Xhol and transcribed with T7 RNA polymerase.
  • Sense and anti-sense Fgf5 transcripts were generated from a plasmid clone (Hebert et al., 1990) containing the full-length Fgf5 coding sequence which had been linearised with either EcoR or Satr?H1 and transcribed with T7 or T3 RNA polymerase respectively.
  • Sense and antisense probes for L17, Psd and K7 were generated from plasmid clones containing 737 bp, 458 bp and 232 bp fragments respectively.
  • Antisense transcripts of L17, Psd and 7 were produced by Xhol digestion and transcription with T3 RNA polymerase (L17, Psd), and Hindlll digestion with transcription with T7 RNA polymerase (K7).
  • Sense probes were generated by BamH1 digestion of clones and transcription using T7 RNA polymerase for L 17 and Psd and T3 RNA polymerase for K7.
  • Antisense Brachyury probes were synthesised from pSK75 (Herrman, 1991 ) linearised with BamHI and transcribed with T7 polymerase. Sense probes were generated from the same plasmid linearised with Hindlll and transcribed with T3 polymerase.
  • Alkaline phosphatase was visualised using the diagnostic kit 86-R (Sigma).
  • the kit was used according to the manufacturer's specifications with the following modification; cell layers were fixed in 4.5 mM citric acid, 2.25 mM sodium citrate, 3 mM sodium chloride, 65% methanol and 4% para-formaldehyde prior to washing and staining.
  • Embryoid bodies were fixed in 4% paraformaldehyde (PFA) in PBS at 4°C overnight before embedding in paraffin wax and sectioning as described in Hogan et al., 1994. Sections were stained with haemotoxylin:eosin.
  • PFA paraformaldehyde
  • MEDII effects the transition of ES to EPL cells in adherent culture When grown in medium supplemented with recombinant LIF (LIF) and in the absence of a feeder cell layer ( Figure 1A) ES cells grow as a homogeneous population with greater than 95% of the colonies displaying a distinctive domed colony morphology.
  • LIF recombinant LIF
  • Figure 1A a feeder cell layer
  • ES cells grow as a homogeneous population with greater than 95% of the colonies displaying a distinctive domed colony morphology.
  • ES cells were seeded and cultured in the presence of mLIF and conditioned medium derived from mammalian cell lines. After 5 days the cells were assessed for divergence from the ES cell colony morphology.
  • EPL early primitive ectoderm-like cells
  • EPL cells resembled P19 EC cells (McBurney and Rogers, 1982; Rudnicki and McBurney, 1987), which are considered similar to cells of the primitive ectoderm.
  • the culture of ES cells in the presence of 50% MEDII resulted in a relatively homogeneous cell population in which greater than 95% of the colonies were of the EPL cell colony morphology and in which no residual ES cell colonies could be detected ( Figure 1 D). This occurred in the presence or absence of added LIF ( Figure 1 D).
  • sporadic colonies of differentiated cells similar to those seen in ES cell cultures, were detected ( Figure 1 D).
  • EPL cells are pluripotent
  • the pluripotent cells of the early mouse embryo and germ line, and ES cells in culture are characterised by expression of the homeobox gene Oct4 and by alkaline phosphatase activity.
  • Oct4 expression is restricted to the pluripotent cells of the early mouse embryo and is down regulated on differentiation of pluripotent cells both in vivo and in vitro.
  • EPL cells were formed by culturing ES cells, in the presence of MEDII or MEDII + LIF, for 2, 4, 6 and 16 days, with passaging every 2 days. Northern analysis of RNA from these populations showed expression of
  • Oct4 at levels equivalent to the levels seen in ES cells ( Figure 2Ai) and suggested that the formation of EPL cells is not equivalent to the process of spontaneous differentiation ( Figure 2Aii).
  • In situ hybridisation of ES cells and EPL cell monolayers with an Oct4 specific anti-sense RNA probe showed Oct4 expression uniformly distributed across the EPL cells, and not restricted to sub-populations of cells within the culture ( Figure 2B,C). Sporadic differentiated cells within the population did not express Oct4 (data not shown).
  • Analysis of alkaline phosphatase activity also showed uniform expression by EPL cells (Figure 2D,E), with down regulation of activity in the differentiated cells (data not shown). The uniform distribution of these pluripotent cell markers in EPL cell cultures demonstrated the homogeneity of EPL cell population.
  • EPL cell formation is accompanied by establishment of primitive ectoderm-like gene expression
  • pluripotent cell marker genes by EPL cells suggested that these cells could be equivalent to a pluripotent cell population of the early embryo, or possibly a differentiated cell lineage in which Oct4 expression was not fully down-regulated.
  • the pluripotent cell populations of the embryo can be discriminated from differentiated cell lineages by morphological and developmental criteria and by the temporal and spatial expression of marker genes.
  • the embryonic equivalent of EPL cells was investigated by analysis of the expression of marker genes that identify the pluripotent cell populations of the embryo, and the differentiated cells of the extra-embryonic lineages and gastrulating embryo.
  • Fgf5 expression is up regulated on the formation of primitive ectoderm from the ICM, whereas both Rex1 and Gbx2 expression can be detected in the ICM but not in the primitive ectoderm by 6.5 d.p.c.
  • the expression of Fgf5 and Rex1 in ES and EPL cells was assessed by Northern blot ( Figure 2A; Table 1).
  • Gbx2 expression was analysed by RNase protection assay ( Figure 2F; Table 1 ).
  • Fgf5 expression which was barely detectable in ES cells, was elevated 50 fold in EPL cells grown for 2 days in MEDII.
  • Fgf5 expression increased in EPL cells with time in culture such that maximal expression, representing a 340 fold induction of Fgf5, was reached by day 6 and persisted for at least 16 days in culture.
  • Rex1 was expressed at high levels by ES cells, but this expression was down regulated 50% within 2 days of EPL cell formation (Figure 2A; Table 1).
  • Rex1 expression was reduced further in EPL cells cultured for longer periods of time such that EPL cells grown in MEDII for 6 days showed a 5 fold reduction in Rex1 expression compared to ES cells.
  • Gbx2 expression was high in ES cells and maintained with 2 days of culture in MEDII, but was reduced with further culture in MEDII to undetectable levels by day 6.
  • EPL cell monolayers cultured for 4 days in MEDII, were probed for Fgf5 expression using DIG-labelled anti-sense Fgf5 transcripts.
  • uvomorulin a cadherin expressed by the pluripotent cells of the ICM and the primitive ectoderm but down-regulated in cells of the primordial germ cell lineage.
  • EPL cells did not express detectable levels of marker genes specific for the extra-embryonic lineages of the early embryo, (H19, AFP) the primitive streak (Evx1) or nascent mesoderm (Brachyury) (Table 1 ; data not shown).
  • EPL cells The morphological transition of ES to EPL cells was found to be accompanied by differential regulation of marker genes that discriminate pluripotent cell populations in vivo. Although gene expression in ES cells was equivalent to their origin from the pluripotent cells of the pre-implantation embryo, EPL cells expressed a repertoire of marker genes which is shared by only one cell population of the early embryo, the primitive ectoderm (Table 1 ). The expression of novel pluripotent cell marker genes supports the relationship between EPL cells and early primitive ectoderm
  • L 17 was expressed highly in the ICM at 3.5 d.p.c. and in the pluripotent cells of the ICM/epiblast at 4.5 d.p.c. ( Figure 5A). L17 expression was down regulated as the ICM/epiblast began to proliferate (day 4.75), and was not detectable following pro-amniotic cavity formation.
  • Psd was expressed in the inner cell mass and at 3.5 d.p.c. and in the pluripotent cells of the ICM/epiblast at 4.5 d.p.c ( Figure 5B). Unlike L 17, Psd expression persisted in the proliferating epiblast bud (4.75 - 5.0 d.p.c.) and was down regulated after the initiation of pro-amniotic cavity formation after 5.0 d.p.c
  • K7 expression was not detected in the pluripotent cells of the ICM/epiblast prior to and including 4.5 d.p.c. (Figure 5C). K7 expression was detected in the pluripotent cells following pro-amniotic cavity formation at 5.25 d.p.c. but was down regulated by 5.5 d.p.c. as the pluripotent cells reorganised to form the columnar epithelial sheet of characteristic of primitive ectoderm.
  • Antibodies to mouse gp130 (RX- 19; Koshimizu et al., 1996), which neutralise the activity of mLIF, hOSM, hlL-6 and hlL-11 , but not hLIF, on myeloid leukemic M1 cells and ES cells (Lake, 1996), and to hLIF (R&D Systems), which neutralises hLIF activity, were used to assess the role of gp130 signalling in EPL cell maintenance.
  • ES cells were seeded into medium containing MEDII, anti-hLIF antibodies
  • EPL cell maintenance was achieved with the addition of between 50 and 100 units/ml of mLIF (data not shown), 10 to 20 fold less than the 1000 units/ml required for the maintenance of ES cells.
  • Oct4 and Fgf5, and brachyury a gene up regulated on the differentiation of pluripotent cells into nascent mesoderm.
  • the expression of Oct4 in EBs was patchy, with areas of cells not staining, suggesting that a proportion of the cells in the aggregate had undergone differentiation.
  • Oct4 expression was detected uniformly throughout the cell layer comprising the EBMs, suggesting that these cells remained pluripotent and had not undergone differentiation.
  • This conclusion was supported by expression of the differentiation specific marker brachyury in approximately 10% of the EBs, suggesting that a proportion of the cells in these aggregates had undergone differentiation to nascent mesoderm.
  • no brachyury expression was detected in the EBMs, indicating that cells within these aggregates had not undergone any differentiation to nascent mesoderm.
  • Fgf5 in aggregates was analysed to assess the formation of EPL cells/primitive ectoderm ( Figure 7B).
  • EBMs Fgf5 was expressed homogeneously throughout the cell layer, indicating that the pluripotent cells in these aggregates represented a uniform population of pluripotent cells which had undergone the transition to form EPL cells/primitive ectoderm.
  • Fgf5 expression in EBs was heterogeneous.
  • RNA extracted from EBs and EBMs supported the findings of the in situ analysis (Figure 8).
  • EBM gene expression was characterised by high levels of Oct4 and Fgf5, diagnostic for primitive ectoderm. Brachyury expression, diagnostic for nascent mesoderm, could not be detected.
  • ES cell EBs expressed a range of genes consistent with the formation of heterogeneous cell types.
  • EBMs in which a variety of cell types ranging from early primitive ectoderm to extraembryonic endoderm to differentiated cells, could be detected, EBMs consisted of a uniform population of cells equivalent to EPL cells and embryonic primitive ectoderm. Control aggregates, developed in 100 units of LIF without MEDII, did not develop as EBMs demonstrating that the alterations seen in pluripotent cell differentiation in the presence of MEDII could not be attributed to the low level of LIF present in MEDII (data not shown).
  • EPL cells were identified as most closely related to cells of the early primitive ectoderm based on gene expression and morphology. The transition from ES to EPL cell could be carried out in adherent culture or in suspension aggregates.
  • ES and EPL cells represent distinct, but interchangeable, pluripotent cell states
  • EPL cells were reverted by seeding a single cell suspension of EPL cells into medium containing 1000 units of LIF in the absence of MEDII at a density of 1.3 x 10 4 cells/cm 2 .
  • ES and EPL cells were introduced to into CBA/C57 F2 blastocysts using standard blastocyst injection technology, as described in Stewart, 1993.
  • Glucose Phosphate Isomerase (GPI) analysis of blood and tissues was as described by Bradley, 1987. Blood samples were collected from the tail. The tissue samples analysed were taken from the brain, eye, femur, heart, intestines, kidneys, liver, lung, muscle, stomach, skin, spleen, tongue, thymus and the ovary or testes. Tissue samples were prepared by freeze/thawing and by homogenisation.
  • Reverted EPL cells exhibited low Fgf5 expression and high Rex1 expression, comparable to the gene expression profile observed in ES cells and distinct from the expression of high levels of Fgf5 and low levels of Rex1 in the parental EPL cells. These data indicated that the phenotypic reversion of EPL cells was accompanied by the establishment of an ES cell gene expression profile. These data also demonstrated a requirement for MEDII for both the establishment and maintenance of EPL cell characteristics.
  • EPL cell lines were generated and reverted to ensure that reversion was not a consequence of residual ES cells within EPL cell populations.
  • EPL cells grown for 4 days in medium containing MEDII but without added LIF, were seeded at limiting dilution in MEDII+LIF to produce clonal EPL cell colonies.
  • Two clones were expanded in MEDII+LIF over 3 weeks before seeding into medium containing mLIF alone or MEDII+LIF. The resulting cultures were assessed for the presence of ES cells, EPL cells and differentiated colonies (Figure 9B).
  • Reverted EPL cells but not EPL cells, contribute to chimeric mice following blastocyst injection.
  • Pluripotent cells from the pre- and post-implantation embryo differ by the ability of the former but not the latter to contribute to embryo development following blastocyst injection.
  • ES cells retain the ability to contribute to all embryonic and adult tissues.
  • E14TG2a ES cells and their EPL cell derivatives were tested for their ability to contribute to chimeric mice when injected into CBA/C57 F2 blastocysts. The contribution of ES cell and EPL cell derivatives to mouse offspring was assessed by coat colour contribution and GPI analysis of blood and tissues.
  • E14TG2a ES cells contributed to the development of 44% of injected blastocysts (Table 2).
  • E14TG2a derived EPL cells grown in MEDII without added LIF for 2 and 4 days such that EPL cell gene expression was established, did not contribute to chimera formation as assessed by coat colour of the 33 and 50 live born pups respectively (Table 2).
  • GPI analysis of blood samples taken from 20 of these mice also failed to detect any contribution from the EPL cells.
  • Analysis of 15 tissue samples taken from two mice also failed to detect any EPL cell contribution. This could not be explained by adverse effects of EPL cells on the viability of injected blastocysts as the percentage of live born pups was comparable from blastocysts injected with ES cells and EPL cells (Table 2).
  • the EPL cells used in the preceding blastocyst injection experiments were reverted by culture in media containing LIF, but not MEDII, for 6 days (2 R and 4 R ). These cells contributed to embryonic development in 36% (2 R ) and 63% (4 R ) of blastocysts injected (Table 2).
  • GPI analysis of blood and tissue samples taken from 10 and 2, respectively, of the chimeric mice generated using reverted EPL cells established that these cells were able to contribute to mesodermai, endodermal and ectodermal derived cell lineages of the adult mouse (data not shown). These data indicated that the ES to EPL eel!
  • EPL cells transition resulted in cells of differing developmental capabilities, reflected in the ability of ES cells, but not EPL cells, to contribute to development when introduced into a host blastocyst.
  • the ability of reverted EPL cells to contribute to chimera development suggests that this loss in chimera forming ability by EPL cells can not be attributed to a loss of pluripotence on EPL cell formation.
  • EPL cells to revert to an ES cell is consistent with the predicted and demonstrated behaviour of other pluripotent cell types, such as the formation of EG cells from primordial germ cells (PGCs) in culture, and supports the deduction that EPL cells are pluripotent. Further, reversion to an ES cell type is a predicted feature of primitive ectoderm. In combination with the demonstrated inability of EPL cells to contribute progeny to chimaeric mice following blastocyst injection, this supports the identification of EPL cells as distinct from ES cells and most closely related to primitive ectoderm. Finally, reversion demonstrates that EPL cells can be used as a substrate for the generation of ES cells in vitro by dedifferentiation or reversion.
  • pluripotent cells from the primitive ectoderm of any mammalian species.
  • Successful isolation and maintenance of pluripotent cells and cell lines from the primitive ectoderm would provide an alternative methodology for isolation of genetically manipulable pluripotent cells with potential for commercial, medical and agricultural application.
  • ES cells preimplantation embryos
  • EG cells primordial germ cell lineages
  • Efficient isolation of pluripotent cell lines is currently restricted to a limited number of inbred mouse strains such as 129, and has not proven successful in other mammals.
  • MEDII supports the formation and maintenance of EPL cells which are most closely related to the pluripotent cells of the primitive ectoderm in the mammalian embryo.
  • EPL cells which are most closely related to the pluripotent cells of the primitive ectoderm in the mammalian embryo.
  • methodology which utilises the biological activity of MEDII to isolate and maintain pluripotent cells from primitive ectoderm.
  • Cell culture conditions, for ES and EPL cells are as in Example 1 except where otherwise specified.
  • Cells isolated from primitive ectoderm were cultured in Dulbecco's Modified Eagles Medium (Gibco BRL), pH 7.4, containing high glucose and supplemented with 15% foetal calf serum (FCS; Commonwealth Serum Laboratories), 40 ⁇ g/ml gentamycin, 1 mM L-glutamine, 0.1 mM ⁇ -mercaptoethanol ( ⁇ -ME), and 1000 units of LIF (embryo culture medium) under 10% C0 2 in a humidified incubator.
  • FCS Dulbecco's Modified Eagles Medium
  • FCS foetal calf serum
  • FCS foetal calf serum
  • ⁇ -ME 0.1 mM ⁇ -mercaptoethanol
  • LIF embryo culture medium
  • Inactivated feeder layers were prepared from either STO cells (ATCC CRL-1503) or primary mouse embryonic fibroblasts (Abbondanzo et al., 1993). Inactivation of feeder cells was achieved by exposing cells to 30 gray of ionising radiation. Feeder cells were seeded at least 6 hours before use at a density of 1 x 10 5 cells/cm 2 in DMEM onto tissue culture plastic treated with human placental collagen IV (Sigma) as per manufactureris instructions. Feeder layers were washed once with DMEM before the addition of culture medium and embryonic explants. Pluripotent cells were identified using the pluripotent specific markers alkaline phosphatase and Oct4 and in situ analysis techniques as described in Example 1.
  • Embryoid bodies were formed as described in Example 1.
  • CBA/C57 F2 embryos were taken from time-mated CBA C57 F1 female mice on the days specified. 0.5 days post coitum was designated as noon on the day of plugging. Mated female mice were killed by cervical dislocation or C0 2 asphyxiation and uteri were kept in DMEM supplemented with 10 mM HEPES, pH 7.4 at 37°C until dissection of embryos. Embryos were removed, using standard dissection techniques, into DMEM supplemented with 10 mM HEPES, pH 7.4. Removal of extraembryonic endoderm was achieved mechanically by pipetting embryos through a pasteur pipette that had been pulled in a flame to a bore diameter slightly smaller than the embryo.
  • Embryoid bodies formed by the aggregation of ES cells in suspension culture, follow a pathway of differentiation equivalent to early mouse embryogenesis with the ordered appearance of extraembryonic and differentiated cell types. The appearance of these cells can be monitored by alterations in gene expression.
  • EB development the pluripotent cell population within the embryoid body is comprised largely or entirely of primitive ectoderm, as determined by expression of the primitive ectoderm markers Fgf5 and Oct4, and down regulation of the ES/ICM cell marker Rex1 ( Figure 10A).
  • Pluripotent cells in EBs are largely differentiated by day 8/9 of culture.
  • EPL cells originated from primitive ectoderm which was shown to be the only pluripotent cell population within the EBs at these stages by the expression of Fgf5 and Rex1 (Figure 10A), and by the failure of medium supplemented with LIF alone to support pluripotent cell proliferation and maintenance (Figure 10B). LIF has been shown to be sufficient for the maintenance of pluripotent ICM or ES cells. Pluripotent cells could be isolated from EB derived primitive ectoderm in either the presence or absence of LIF, but was dependent on the presence of MEDII.
  • MEDII can support the maintenance and proliferation of pluripotent cells from the primitive ectoderm of EBs.
  • the pluripotent cells isolated from the primitive ectoderm were equivalent to EPL cells in morphology and gene expression, and could be reverted to ES cells when cultured in the presence of LIF and the absence of MEDII (data not shown; Example 2).
  • Pluripotent cells isolated from the primitive ectoderm of EBs in this way and reverted to ES cells have been shown to contribute to chimaeric mice when introduced into host blastocysts.
  • the goal of this investigation was the isolation and maintenance of pluripotent cells from the primitive ectoderm of a non-129 strain of mice.
  • Primitive ectoderm from 5.5 d.p.c. embryos is a preferred substrate for pluripotent cell isolation
  • the number of embryo explants containing alkaline phosphatase positive cells was greatest in explants of day 5.5 d.p.c embryos (varying between 25% and 40%) and decreased significantly with increasing age of the embryo to less than 5% in explants of day 7.5 d.p.c. embryos.
  • the abundance of alkaline phosphatase positive cells in explants of 5.5 d.p.c embryos was variable, but most explants comprised 20% or greater alkaline phosphatase positive cells.
  • 5.5 d.p.c. embryos were used as the source of primitive ectoderm in subsequent experiments.
  • ECM extracellular matrix
  • EPL/primitive ectoderm cells in culture was tested by seeding ES cells at low density (2.5 x 10 2 cells/cm 2 ) in DMEM + LIF or DMEM + 50% MEDII onto tissue culture plastic which had been pretreated with gelatin (Example 1), plasma fibronectin, laminin, collagen IV (all obtained from Sigma and used as per the manufacturers specifications) and a combination of plasma fibronectin, laminin and collagen IV.
  • the selected purified ECM components have been shown to be present in the extracellular matrices of the early embryo. Cells were cultured for 5 days and stained for alkaline phosphatase. Colonies were classified on the presence or absence of differentiated (alkaline phosphatase negative) cell types within the colony and the presence of differentiated cells was used as a measure of pluripotent cell stability (Table 3).
  • gelatin was the least favourable for EPL cell stability, with 78% of EPL cell colonies containing at least some differentiated cells.
  • the purified matrix components all resulted in more stable EPL cell cultures when compared to gelatin, with collagen IV and the matrix mix containing collagen IV resulting in 59% and 62.5% undifferentiated EPL cell colonies respectively.
  • ES cells cultured in the absence of MEDII were stable on all the tested matrices.
  • Tissue culture plastic pretreated with collagen IV was used for the culture of pluripotent cells from primitive ectoderm in subsequent experiments.
  • the visceral endoderm is recognised as a source of inductive signals involved in the differentiation of pluripotent cells during gastrulation. Removal of visceral endoderm from embryonic explants was performed to eliminate this source of differentiation inducing signals and promote pluripotent cell stability in culture. Although the effect of this step has not been quantified, successful isolation and maintenance of pluripotent cells from the embryo has not been achieved from explants comprising primitive ectoderm and extraembryonic endoderm.
  • Embryos were dissected from the uteri of time mated female mice between 10 and 11 a.m. on the morning of the sixth day of gestation (approximately 5.4 d.p.c). Each embryo was dissected to remove Reichart's membrane, the extraplacental cone and the visceral endoderm layer, resulting in a cup shaped structure comprising primitive ectoderm in the absence of contaminating cell types ( Figure 12B). All tissues were removed from the embryos mechanically. Primitive ectoderm explants were placed individually into 2 ml wells plugged with agarose and cultured in 1 ml of embryo culture medium + 50% MEDII. Embryos were cultured at 37°C in a 10% C0 2 humidified incubator.
  • the work described in this example provides the first demonstration that pluripotent cells from embryonic primitive ectoderm can be isolated and maintained in culture as pluripotent cells analogous to EPL and ES cells for extended periods. Culture and passage of these cells was dependent on the biological activity contained within MEDII. Pluripotent cells obtained in this manner are likely to be amenable to genetic manipulation and represent a resource with potential commercial, medical and agricultural application.
  • the demonstration that pluripotent EPL and ES cells can be isolated from the primitive ectoderm of mouse species that are refractory to ES and EG cell isolation by other methodologies potentially provides an opportunity for the isolation of pluripotent cell lines from other mammalian and avian species.
  • Serum free MEDII Serum free MEDII
  • SfMEDII Serum free MEDII
  • Hep G2 cells were seeded at a density of 5 x 10 4 cells/cm 2 and cultured for three days.
  • Morphology based assays to test the EPL cell-inducing activity of purified fractions were performed with D3 ES cells. Assays were carried out in 2 ml wells (Falcon) in a total volume of 1 ml/well. ES cells (2.5x10 2 cells/cm 2 ) were cultured in the presence of semi-purified fractions and scored microscopically for EPL cell morphology after 4 days in culture, and macroscopically after 5 days following staining for alkaline phosphatase activity.
  • Extracellular matrix preparations were formed as follows. Hep G2 cells were grown to confluence under conditions described in Example 1. Cells were incubated in 0.5% Sodium Azide/0.1 mM PMSF in PBS for 6-18 hours at 37°C or room temperature to kill and detach cells, or cultured in 0.5mM EGTA for 15 minutes at room temperature to detach cells. Cells and debris were removed by washing with PBS. Formation of matrices from semi-purified or purified proteins was achieved by drying 1-2 ⁇ g of protein onto a 2 ml tissue culture well.
  • ES cells were seeded onto matrices at a concentration of 2.5x10 2 cells/cm 2 in DMEM supplemented with 1000 units/ml LIF and 10 ⁇ g/ml L-proline. Cell morphology was assayed microscopically on day 4 and following staining for alkaline phosphatase activity on day 5.
  • Collagen IV 250mg Collagen IV (Sigma) was digested with 3 FALGPA units of collagenase type IV (Sigma) in 50 mM Tris.CI pH 7.4, 100 mM CaC1 2 buffer in a final volume of 10 ml and incubated overnight at 37°C with continuous mixing.
  • Digested collagen fragments were separated from enzyme and undigested protein by ultrafiltration through an Amicon Diaflo YM3 membrane using a 400ml ultrafiltration cell (Amicon) at 4°C under nitrogen pressure. The eluate obtained from ultrafiltration was passed through a 0.22 ⁇ m filter and 1.5 ml aliquots were lyophilised and resuspended in 200 ⁇ l water.
  • Protein samples were obtained directly from conditioned medium, or chromatographic fractions were desalted on a Centricon-10 column (Amicon) and made to the original volume with 20 mM Tris.CI pH 8.5. Samples were electrophoresed on 10% reducing SDS polyacrylamide gels as described by Laemmli, 1970 and proteins were visualised by silver staining using the method of Heukeshoven and Dernick (1985).
  • the reaction was developed in western substrate mix (10ml western buffer 2, 40ul NBT (75 mg/ml in 70% DMF), 40ul BCIP (50 mg/ml in 100% DMF)) in the dark and stopped by the addition of 10 ml Western buffer 1 , 100 mM EDTA.
  • SfMEDII was separated into two fractions by ultrafiltration through a 10x10 3 M r cut-off membrane (Centricon-3 unit; Amicon). Both fractions were assayed for EPL forming activity (Figure 14), defined as the ability to cause the complete conversion of D3 ES cells to alkaline phosphatase positive EPL cells in the presence of mLIF. ES cells seeded into the retained fraction (>3x10 3 M r ) at concentrations equivalent to 50% MEDII did not form EPL cells, although there was an increase in the size of the ES cell colonies.
  • ES cells seeded into the eluted fraction ( ⁇ 3x10 3 M r ) at concentrations equivalent to 50% MEDII gave rise to an array of colony morphologies including ES, EPL and differentiated cells.
  • the presence of ES cells and the higher proportion of differentiated cells was uncharacteristic of the ES to EPL cell transition, demonstrating that the eluted material alone was unable to induce EPL cell formation.
  • Seeding of ES cells into medium containing both the retained and eluted fractions at concentrations equivalent to 50% MEDII resulted in uniform EPL cell formation, equivalent to that seen for sfMEDII.
  • the starting material for purification and analysis of bioactive factors from MEDII was derived by ultrafiltration of sfMEDII over an Amicon Diaflo YM3 membrane using a 400ml ultrafiltration cell (Amicon) at 4°C under nitrogen pressure.
  • the retained fraction (R), >3x10 3 M r was used immediately or aliquoted and stored at -20°C.
  • the eluted fraction (E), ⁇ 3x10 3 M r was used immediately or stored at 4°C.
  • the low molecular weight component of the EPL cell-inducing activity was assayed as described above except that 1ml culture medium was supplemented with 20 ⁇ l (50-100 ⁇ g protein) of R which had been passed over a PD10 column (Pharmacia) to remove low molecular weight contaminants.
  • Fractions 7 to 9 were pooled, lyophilised and resuspended in 1 ml of 30:70 methanokacetonitrile. Samples were centrifuged at 14,000rpm for 10 minutes to remove precipitates and applied to a 10 mm Waters radial pak normal phase silica column (8 mm I.D.) attached to a Waters 510 HPLC machine. The column was washed with 30:70 methanol: acetonitrile at a flow rate of 0.2 ml/minute for 15min before the material was eluted with a 20min linear gradient against water using a flow rate of 0.5 ml/minute.
  • Fraction 9 from the Superdex peptide gel filtration column was lyophilised, derivatised with FMOC and OPA and amino acid analysis was conducted with and without hydrolysis using a Hewlett-Packard Amino-Quant II analyser. Results were compared with a control sample of non-conditioned medium subjected to an identical purification (Table 6). The amino acid alanine and the imino acid proline were present in abundance compared to the control in both hydrolysed and unhydrolysed samples. This indicates that these amino acids were present within the purified sample as free amino acids and not a peptide.
  • L-proline (3 x 10 '4 M) and L-alanine (3.9 x 10 "4 M) were assayed for EPL cell- inducing activity.
  • L-proline effected conversion of ES cells to EPL cells in the presence of R in a manner indistinguishable from the low molecular weight component of sfMEDII. This included the alterations in morphology, and Fgf5 and Rex1 expression reported in Example 1 (data not shown).
  • L-alanine had no effect on ES cells in the presence or absence of R.
  • the minimal active molar concentration of proline was found to be approximately 40 ⁇ M.
  • the optimal concentration in biological assays was found to be 100 ⁇ M.
  • Proline analogues reported to have proline-like bioactivity in other cell systems and proline-containing peptides were tested over a range of concentrations to assess their ability to form EPL cells from ES cells in the presence or absence of R. Results are presented in Table 7.
  • Sarcosine, L-azetidine-2-carboxylic acid (AZET) and 3,4 dehydro-L-proline inhibited ES cell growth at lower concentrations and caused ES cell death at higher concentrations without inducing EPL cell formation in the presence or absence of R.
  • EPL cells were also formed when ES cells were cultured in the presence of R and partially purified collagen IV hydrolysate, resulting from collagenase digestion of collagen IV. Free L-proline could not be detected within the partially purified collagen IV hydrolysate by TLC.
  • the bioactivity of collagen IV hydrolysate presumably reflects the presence of repeating Gly-Pro-X motifs in collagen IV proteins and provides a possible source of this bioactivity in vivo by breakdown of ECM components.
  • the tachykinin substance P induced apoptosis of ES cells. Compared to substance P free acid and substance P fragment 1-4, substance P has a markedly increased affinity for the NK-1 receptor.
  • L-proline and proline-containing peptides have the bioactivity associated with the low molecular weight component of sfMEDII.
  • the identification of multiple factors with similar but distinct specific activities points to structural requirement for bioactivity, suggests the involvement of receptor interaction, and allows prediction of additional peptides with the low molecular component of the EPL cell-inducing activity.
  • the large molecular weight component of the EPL cell-inducing activity was assayed as described previously except that 1 ml culture medium was supplemented with 500 ⁇ l of E (made to 10% FCS) or 40 ⁇ M L-proline.
  • fractions were prepared for inclusion in the assay as follows.
  • the protein concentration of semi-purified fractions of R from chromatographic purification steps was estimated using a BioRad Protein Assay kit (BioRad # 500-0001). Aliquots of each fraction containing 100 ⁇ g of protein were concentrated on centricon-10 units (Amicon), washed with 2 ml of PBS and reconcentrated. Each fraction was assayed for the large molecular weight component of the EPL cell-inducing activity at a range of concentrations, from 0.1 ⁇ g to 10 ⁇ g of protein. Physiochemical properties of the large molecular weight component
  • the physiochemical properties of the low molecular weight component of the EPL cell-inducing activity were deduced from treatment and assay of R, prepared as above except that an Amicon Diaflo YM10 membrane was used for ultrafiltration. R was passed over a PD10 column (Pharmacia) to remove low molecular weight contaminants and used in assays at approximately 50-100 ⁇ g/ml. Treatment of R by incubation at >56°C for 1 hour, or digestion with the protease trypsin resulted in the loss of biological activity. The large molecular weight component of the EPL cell-inducing activity was also unstable at pH 5.5 and below, or following treatment with reducing agents such as 100 mM DTT for 4 hours at room temperature. These data indicated that the large molecular weight component of the EPL cell-inducing activity was proteinaceous.
  • ECM extracellular matrix
  • ES cells were seeded onto Hep G2 ECM in 2 ml tissue culture wells at low cell density, 2.5x10 2 cells/cm 2 , and cultured for 5 days in DMEM + LIF, with or without L-proline. Cultures were stained for alkaline phosphatase activity after 5 days and the cultures were assessed by morphology for EPL cell formation. Matrix from Hep G2 cells was able to act as a source of the large molecular weight component of the EPL cell-inducing activity and effectively induced the formation of EPL cells when used in combination with L-proline (Table 8). When used alone the matrix was unable to induce complete conversion of ES to EPL cells, however a number of the colonies adopted a flattened or spread morphology. TABLE 8
  • Protocol 1 Purification of the large molecular weight component from sfMEDII: Protocol 1
  • the active fraction from anion exchange chromatography was made to a final concentration of 0.5M ammonium sulphate in 20 mM Tris.CI pH 8.5.
  • the sample was filtered through a 0.22 ⁇ m filter to remove precipitated material before being passed over a 40 ml phenyl Sepharose fast flow hydrophobic interaction column (Pharmacia).
  • Bound protein was eluted from the column in a single step with 50 ml 20 mM Tris.CI pH8.5 ( Figure 16B) and shown by assay to contain the large molecular weight component of the EPL cell-inducing activity.
  • the active fraction from hydrophobic interaction chromatography was diluted in 20 mm Tris.CI pH8.5 to a conductivity below 100 mM NaCl.
  • the sample was passed over a 10 ml Heparin Sepharose CL-6B column (Pharmacia). Bound protein was eluted from the column in a single step with 10 ml 0.5M NaCl, 20 mM Tris.CI pH 8.5 ( Figure 16C) and shown by assay to contain the large molecular weight component of the EPL cell-inducing activity.
  • the active fraction from Heparin Sepharose affinity chromatography was passed down a Superose 6 gel filtration column (Pharmacia) on the SMART system (Pharmacia) in 20 mM Tris.CI pH 8.5, 150 mM NaCl ( Figure 16D). 50 ⁇ l fractions were collected and assayed directly. Fractions containing bioactivity equivalent to the large molecular weight component of sfMEDII eluted as a single peak between 500-1000 kDa. EPL cell formation was only observed in the presence of E or L-proline.
  • Protocol 2 Purification of the large molecular component from sfMEDII: Protocol 2
  • the active fraction from Heparin Sepharose affinity chromatography was diluted to 150 mM NaCl with 20 mM Tris.CI, pH 8.5 and applied to a 1 ml Resource Q anion exchange column (Pharmacia) pre-equilibrated with 20 mM Tris.CI, pH 8.5 + 150 mM NaCl. Proteins were eluted from the column with a gradient from 150 mM to 500 mM NaCl over 60 minutes, followed by a 5 minute wash in 1 M NaCl at 1 ml/min ( Figure 17B). Alternate 1.5 ml fractions were assayed for the high molecular weight component of the EPL cell-inducing activity which eluted from this column in 200-300 mM NaCl.
  • the active fraction was analysed by reducing SDS PAGE and shown to contain a highly purified protein of approximately 210-260 kDa (Figure 17D), equivalent to the protein purified in protocol 1.
  • Protocol 3 Purification of the large molecular component from sfMEDII: Protocol 3
  • the eluate was analysed by reducing SDS PAGE and shown to contain a highly purified protein of approximately 210-260 kDa (Figure 18B), equivalent to the protein purified in protocols 1 and 2.
  • the yield of purified protein was determined by Bradford analysis to be approximately 1 mg/litre sfMEDII.
  • the highly purified active fractions obtained from purification protocols 1-3 were able to induce EPL cell formation in the presence of E or L-proline when used either in solution at 2 ⁇ g/ml ( Figure 19C) or when pre-coated onto tissue culture plastic (data not shown). This is consistent with previous identification of the protein as a component of the ECM. EPL cell-inducing activity could not be detected in the absence of E or L-proline.
  • ECM proteins can be used to provide the large molecular weight component of the EPL cell-inducing activity when presented to cells as a matrix
  • Fibronectin and laminin bind to cells via cell surface integrin receptors, with the specificity of ligand binding determined by various heterodimeric combinations between alpha and beta integrins.
  • Size fractionation of sfMEDII revealed a requirement for at least two biologically active factors in EPL cell formation, a large molecular weight and a low molecular weight component.
  • the low molecular weight component of sfMEDII was identified as L-proline, active at concentrations of 40 ⁇ M and above.
  • Analysis of proline analogues and small peptides demonstrated that a number of small, proline containing peptides could substitute for L-proline in the formation of EPL cells.
  • Chromatographic purification by a variety of protocols identified the large molecular weight component of sfMEDII as cellular fibronectin.
  • the large molecular weight component or cellular fibronectin was able to effect the formation of EPL cells both in solution and as a matrix.
  • the ability of several extracellular matrix components to induce formation of EPL cells when presented to ES cells in matrix-associated but not soluble form and in combination with L-proline suggested that the biological activity of cellular fibronectin was mediated by integrins at the cell surface, most probably an alpha 1 :beta 5 heterodimer.
  • Biologically active components of the EPL cell-inducing activity can be isolated from divergent sources and species
  • liver cells were prepared using procedures based on procedures described by Giger and Myer (1981), with minor variations. Mice were sacrificed and immediately dissected to expose the liver. Each liver was perfused through the portal vein with 10 ml PBS, followed by 10 ml 0.05% collagenase in Hanks buffered salt solution (HBSS; 0.8g KCI, 0.12g KH 2 P0 4 , 16g NaCl, 0.1g Na 2 HP0 4 , 2g glucose, 4 ml 1% phenol red, .035g NaHC0 3 in 2 litres). The perfused liver was removed, macerated in 10 ml/liver of 0.05% collagenase/HBSS and incubated at 37°C for 30 minutes.
  • HBSS Hanks buffered salt solution
  • Liver suspensions were regularly agitated by pipetting to aid liver disaggregation.
  • Cells were washed twice in HBSS (10 ml) to remove collagenase, and contaminating eyrthrocytes were lysed in Sassa solution (6.95g NH 4 CI, 2.058g Tris-base, 1g KHCO 3 / litre).
  • Sassa solution (6.95g NH 4 CI, 2.058g Tris-base, 1g KHCO 3 / litre).
  • Williami ' s E medium (1 ml/liver, Gibco BRL
  • the cells were seeded into gelatin treated tissue culture flasks in DMEM and incubated at 37°C, 5% C0 2 .
  • avian hepatocytes were prepared from 17-18 day chick embryos. In brief, chick embryos were removed from the egg, decapitated and dissected to expose the heart and liver. The liver was perfused, via cannulation of the heart, with 10 ml of 0.9% NaCl containing 2 mM EDTA to remove blood cells, followed by 4 ml of 0.05% collagenase in HBSS. Livers were removed, pooled in HBSS and transferred into fresh 0.05% collagenase/HBBS when all livers had been perfused and collected.
  • mice hepatocellular carcinoma cell lines Hepa-1c1 c 7 ATCC CRL- 2026 and Hep 3B (ATCC HB-8064), and the P19 embryonal carcinoma derived cell lines END2 (visceral endoderm like, Mummery et al., 1985) and PYS2 (parietal endoderm like, Lehman et al., 1974), were maintained in DMEM.
  • Conditioned medium was collected after cell lines had been cultured for 4 days in non-gelatinised tissue culture flasks at 37°C, 5% C0 2 .
  • Conditioned medium was processed as described for MEDII in Example 1. Conditioned medium was assayed for biological activity as described in Examples 1 and 4.
  • Conditioned medium from the primary hepatocytes both mouse and chicken, was able to effect the transition of ES to EPL cells in culture (Figure 21 A). This was only true of medium taken from seeded primary liver cells. Passaging resulted in loss of hepatocytes, which were overgrown by cells of fibroblastic appearance, and loss of EPL cell-inducing biological activity. No difference in biological activity was detected in conditioned medium from primary embryonic (chick) and adult (mouse) hepatocytes and MEDII.
  • Conditioned medium from Hep 3B cells was unable to effect the ES to EPL cell transition, alone or in combination with components of the biological activity purified from MEDII. These cells, and several other liver-derived cell lines did not express detectable levels of cellular fibronectin ( Figure 21 C), indicating that expression of the large molecular weight component of the EPL cell-inducing activity is not ubiquitous among liver derived cell lines.
  • Conditioned medium from END-2 cells induced formation of EPL cells from ES cells when used in conjunction with cellular fibronectin (Figure 21 B), suggesting that these cells secrete L-proline or a functional analogue but not cellular fibronectin ( Figure 21 C).
  • Semipurification of the conditioned medium by normal phase chromatography (Example 4) and analysis by thin layer chromatography demonstrated the presence of L-proline in END-2 conditioned medium (data not shown).
  • the KSF4 ES cell line which constitutively expresses nuclear localised LacZ (Berger et al., 1995; obtained from Patrick Tarn, CMIR, New South Wales. Australia), was maintained on inactivated primary mouse embryonic fibroblast feeder layers (Abbondanzo et al., 1993) in DMEM (high glucose) supplemented with 40 ⁇ g/ml gentamycin, 20% foetal calf serum (FCS), 0.1 mM ⁇ -mercaptoethanol, I mM L-glutamine and 1000 units LIF as before. Prior to the formation of EPL cells, KSF4 cells were cultured on gelatin treated tissue culture plastic, in the absence of a feeder layer, for two passages.
  • EBs embryoid bodies
  • DMEM partial trypsinisation method
  • EBs were formed from a single cell suspension plated at 1x10 5 cells/ml in bacteriological dishes in ES DMEM, or suspended in a hanging drop of medium (50 ⁇ l) at 1.6x10 4 on the inside surface of a petri dish lid. Cell aggregates formed in suspended drops were transferred to bacteriological dishes for further culture after 48 hours. EBs were maintained with regular replenishing of medium.
  • Mixed cell EBs were formed from a single suspension as previously described, in which the two cell populations were mixed at the specified ratio.
  • EPL cells derived from a variety of ES cell lines including, D3 (Doetschman et al., 1985), MBL5 (Pease et al., 1990), KSF-4 (Berger et al., 1995) and E14 (Hooper et al., 1987), and using alternative methods of EB formation, including single cell suspension, hanging drop and partial trypsinisation. Furthermore the differentiation potential reported for EPL cells was specifically associated with these cells as it could not be recapitulated by ES cells which had been spontaneously differentiated by culture in the absence of LIF for equivalent time periods (data not shown).
  • Retinoic acid (RA) differentiation of pluripotent cell aggregates was carried out by plating ES or EPL cells in bacteriological dishes, at a density of 1x10 5 cells/mi, in DMEM supplemented with 1 ⁇ M RA. After 48 hours, aggregates were transferred to DMEM and maintained for 2 days, then seeded individually into 2 ml tissue culture wells. The presence of neurons was assessed by microscopic examination two days after seeding. Neuron identity was confirmed by positive staining with the neurofilament 200 antibody N-4142 (Sigma).
  • cytokines/growth factors were carried out on ES cells and EPL cells seeded at low density (75 cell/cm 2 ) in 4 well multidishes (Nunc) in 0.8 ml of DMEM + LIF or DMEM + 50% MEDII + LIF respectively. Cytokines/growth factors were added at specified concentrations and the assays were stained for alkaline phosphatase activity after 5 days of culture as described in Example 1.
  • Probe fragments used for northern blot analysis and/or in situ hybridisations were as detailed in Example 1 with the addition of; AFP, linearisation of a plasmid containing a 400 bp EcoRI fragment encoding the first 350 bp of mouse AFP cDNA in pBluescript KS II+ (obtained from Dr. R. Krumlauf, NIMR, London) with Hindlll followed by transcription with T3 polymerase; SPARC, 570 bp EcoRI fragment derived from 13G43 (Mason et al., 1986); Goosecoid, linearisation of a plasmid containing 909 bp goosecoid genomic DNA (Blum et al.
  • Nkx2.5 linearisation of plasmid containing 1.6 kb Nkx2.5 cDNA (Lints at al., 1993) with Hindlll and transcription with T3 polymerase.
  • EBs were fixed in 4% paraformaldehyde (PFA) in PBS at 4°C overnight and processed and sectioned as described in Example 1. Sections were stained with toluidine blue for 10 seconds, cleared in Histoclear (National Diagnostics) and coverslipped using a xylene-based mounting medium. EBs subjected to in situ hybridisation were fixed in 4% PFA overnight, washed several times with PBS, 0.1 % Tween-20, treated with 100% methanol for 5 minutes and then isopropanol for 10 minutes. Bodies were then embedded and sectioned as described in Example 1.
  • PFA paraformaldehyde
  • EBs were fixed in 0.2% gluteraldehyde in PBS for 15 minutes on ice, washed 3x15 minutes with detergent rinse (0.1 M phosphate buffer (pH 7.3), 2 mM MgCI 2 , 0.01 % sodium deoxycholate, 0.02% Nonidet P-450) and stained in detergent rinse containing 5 mM potassium ferricyanide, 5 mM potassium ferrocyanide and 1 mg/ml X-gal for 2 hours at 37°C. EBs were then washed 3x with detergent rinse and transferred to 70% EtOH. For sectioning, EBs were dehydrated to 100% ethanol and processed as described in Example 1.
  • detergent rinse 0.1 M phosphate buffer (pH 7.3), 2 mM MgCI 2 , 0.01 % sodium deoxycholate, 0.02% Nonidet P-450
  • AFP expression in sectioned EBs was carried out essentially as described by Dziadek and Adamson (1978) with the following modifications. Prior to antibody incubations, endogenous peroxidase activity was blocked by incubation of the section in 3% H 2 0 2 in methanol for 30 minutes. Sections were incubated with a 1/200 dilution of rabbit anti-AFP (ICN) for 2 hrs, washed several times with PBS then incubated with 1/200 dilution of HRP-conjugated anti-rabbit IgG (Silenus).
  • ICN rabbit anti-AFP
  • Beating cardiocyte formation was assessed in individual EBs, formed from either ES or EPL cells, plated onto pre-equilibrated agarose plugs (1 % agarose in DMEM medium base equilibrated against DMEM for 3 hours at 37°C, 10% C0 2 in 2 ml tissue culture wells) in DMEM.
  • the presence or absence of beating muscle was assessed at days 4, 6, 8, 10 and 12 by microscopic examination.
  • beating muscle formation was assessed in individual EBs seeded into 2 ml wells at day 6 of development and scored microscopically at days 7, 8, 10, 12, 14 and 16. Seeded aggregates were also scored for the presence of terminally differentiated neurons on days 8, 10 and 12.
  • Embryoid bodies formed by aggregation of pluripotent cells in suspension, follow a pathway of differentiation reminiscent of early embryogenesis (Example 1 ) and provide an opportunity for broad assessment of pluripotent cell differentiation into both embryonic and extraembryonic cell types.
  • the term EB is used herein to describe pluripotent cell aggregates cultured in DMEM.
  • ES cell EBs comprised a homogeneous population of round, relatively smooth and ordered aggregates (Figure 22A). EBs formed from EPL cells also formed a homogeneous population, however the bodies appeared irregular and disorganised ( Figure 22B). Sectioning and staining indicated that while ES cell EBs comprised a relatively uniform population of cells characterised by a compacted round morphology ( Figure 22C), pronounced of undifferentiated pluripotent cells, internal cells in EPL EBs were loosely packed and heterogeneous, possibly reflecting differentiation (Figure 22D). This observation prompted a detailed comparative investigation of ES and EPL cell differentiation.
  • Rex1 is expressed by ICM and ES cells, and is down regulated in EPL cells, the primitive ectoderm at 6.0 d.p.c. and during ES cell differentiation in vitro.
  • Fgf5 is not expressed by ICM or ES cells, but is expressed in EPL cells and the primitive ectoderm prior to and during gastrulation, and up regulated transiently during ES cell differentiation in vitro.
  • Oct4 is expressed by all pluripotent cell populations of the embryo, EPL cells and ES cells, and is down regulated upon differentiation of these cells in vivo and in.
  • Rex1 Although the expression of Rex1 was found to be down regulated in both ES and EPL cell embryoid bodies, the kinetics of Rex1 regulation differed between the two cell populations. Down regulation to a barely detectable, basal level was observed by day 1 in EPL cell embryoid bodies ( Figure 23). In contrast, a similar level of Rex1 expression was not observed in ES cell embryoid bodies until day 2, with intermediate levels of expression observed on day 1. Similarly, the kinetics of Fgf5 regulation differed between embryoid bodies derived from ES or EPL cells. Fgf5, already expressed in EPL cells, was up regulated rapidly from day 1 in EPL cell embryoid bodies to a peak on day 2/3, followed by a marked decrease in expression on day 4.
  • the EPL cell embryoid body environment is non-permissive for visceral endoderm formation
  • pluripotent cells exposed to the blastocoelic cavity have differentiated to form primitive endoderm.
  • the primitive endoderm gives rise to two distinct endodermal cell populations, visceral endoderm, which remains in contact with the epiblast, and parietal endoderm, which migrates away from the pluripotent cells to form a layer of endoderm adjacent to the trophectoderm.
  • visceral endoderm which remains in contact with the epiblast
  • parietal endoderm which migrates away from the pluripotent cells to form a layer of endoderm adjacent to the trophectoderm.
  • formation of an outer layer of endoderm, containing both visceral and parietal endoderm cells can be observed in embryoid bodies by day 4 or 5 of development. This timing is coincident with formation of primitive ectoderm and creation of an inner cavity, events that accompany endoderm specification in the embryo. Analysis of endoderm formation at this stage is therefore more likely to reflect normal embryonic events.
  • EPL cells to form visceral endoderm reflected an inherent restriction in the developmental potential of these cells or an alteration in the embryoid body environment.
  • the KSF-4 ES cell line constitutively expresses a LacZ gene modified to target ⁇ -galactosidase protein to the nucleus.
  • Analysis of embryoid bodies formed from KSF-4 ES cells demonstrated formation of visceral endoderm at levels comparable with D3 ES cells (data not shown).
  • KSF-4 ES cells were cultured for 2 days in MEDII to form KSF-4 EPL cells (EPL (LZ+)).
  • Embryoid bodies generated by co-aggregation of a 1 :1 ratio of D3 ES cells and EPL (LZ+) cells were assessed for visceral endoderm formation by AFP expression at day 4.
  • ES cell embryoid bodies and EPL (LZ+) cell embryoid bodies gave rise to visceral endoderm at levels consistent with those previously described (65% and 0% of bodies respectively).
  • Embryoid bodies formed from the mixed cell population gave rise to visceral endoderm at levels comparable to ES embryoid bodies (51%).
  • Double staining for ⁇ -galactosidase activity and AFP expression revealed the presence of both LacZ+ and LacZ- cells within the visceral endoderm ( Figure 25).
  • EBs from EPL cells provides a methodology for the differentiation of pluripotent cells in the absence of visceral endoderm.
  • Visceral endoderm is known to express signals that influence pluripotent cell differentiation in vivo. Differentiation in the absence of this cell type provides an opportunity for specific control of pluripotent cell differentiation by the addition of factors and environmental alteration. This cannot be achieved in ES cell EBs in which pluripotent cell differentiation is at least partly controlled by signals from visceral endoderm which differentiate spontaneously from exterior ES cells.
  • brachyury and goosecoid expression were up regulated 30 and 6 fold respectively on days 2 and 3 of EPL cell EB development, followed by 9 (brachyury) and 6.5 (goosecoid) fold decreases in expression on day 4 ( Figure 26).
  • the expression of mesodermai markers immediately preceded decreases in the expression levels of primitive ectoderm markers Fgf5 and Oct4 ( Figure 23).
  • Brachyury expression in ES cell embryoid bodies did not reach the levels seen in EPL cell bodies at day 3/4 even after extended culture.
  • Oct4 expression was relatively uniform throughout control EBs on days 3 and 4 (Figure 26F,H), but patchy within EPL cell EBs where mesoderm differentiation had commenced ( Figure 26G,I).
  • the comparison of markers specific for nascent mesoderm suggested that EPL cell embryoid bodies undergo an accelerated differentiation program resulting in the earlier appearance and more extensive formation of mesoderm compared to ES cell embryoid bodies.
  • Terminal differentiation of nascent mesoderm was monitored by the appearance of beating cardiocytes (Figure 27A). This was first detected in ES cell EBs at day 8 of development (8%) and increased with time, reaching 36% of bodies at day 12.
  • beating muscle was observed in 14% embryoid bodies by day 6, two days prior to its appearance in ES cell EBs, and increased steadily to 60% by day 10 and 12 of embryoid body development.
  • the proportion of EPL cell EBs containing beating muscle was higher than ES cell EBs at all time points. Consistent with this profile, expression of Nkx2.5 was induced earlier in EPL cell EBs, by day 6 compared to day 8 in ES cell EBs (Figure 27B).
  • EPL cell embryoid bodies exhibit reduced capacity for neuron formation
  • EPL cells into ectoderm derived lineages was assessed by the presence of neurons within individual embryoid bodies ( Figure 28A), and compared to ES cell EBs. Neurons were not detected in either embryoid body population before day 10. On day 10, 26% of ES cell EBs contained obvious neural networks. This rose to 41% by day 12. Embryoid bodies derived from EPL cells failed to form neurons.
  • ES cells and P19 embryonal carcinoma (EC) cells form neurons when differentiated as aggregates in the presence of retinoic acid (RA).
  • RA retinoic acid
  • Individual RA-treated ES and EPL cell aggregates were scored for the presence of neurons ( Figure 28B) and found to exhibit similar frequencies of neuron formation at 63% and 68%, respectively. This indicated that the absence of neurons within EPL cell EBs did not reflect an inherent restriction in the capacity of EPL cells to form neurons, but an altered embryoid body environment which resulted in reduced neural specification.
  • EPL cell EBs formed nascent mesoderm and mesoderm derivatives with high efficiency, but failed to form neurons despite retaining neuron-forming potential. Differentiation in EPL cell EBs may reflect directed formation of the mesoderm germ layer from pluripotent cells cultured under these conditions. This may result from the demonstrated failure of EPL cell EBs to form an outer layer of visceral endoderm which has been demonstrated to play a role in the specification of ectodermal lineages. Differentiation of EPL cells in response to cytokines/growth factors
  • ES and EPL cells were seeded into DMEM + LIF or DMEM + 50% MEDII + LIF respectively at a density of at 75 cells/cm 2 .
  • Cells were cultured in the presence of increasing concentrations (0.1-100 ng/ml) of recombinant bovine basic fibroblast growth factor (bFGF; Boehringer Mannheim) for a period of 5 days.
  • bFGF bovine basic fibroblast growth factor
  • Addition of bFGF to ES cells in the presence of LIF had no effect on ES cell morphology, differentiation or proliferation.
  • addition of 10 ng/ml or higher concentrations of bFGF induced the differentiation of EPL cells to a characteristic cell type (cell type A; Figure 17A) which did not stain for alkaline phosphatase.
  • Activin A induces the differentiation of EPL cells but not ES cells.
  • ES and EPL cells were seeded at a density of 75 cell/cm 2 .
  • Cells were cultured for 5 days in DMEM + LIF or DMEM + 50% MEDII + LIF respectively, to which had been added increasing concentrations of recombinant human activin A
  • Activin A had no effect on ES cell morphology, differentiation or proliferation at any concentration tested. Addition of activin A to EPL cells in culture induced their differentiation. After 5 days the majority of colonies in activin A treated wells had a distinctive colony morphology (Figure 29C) characterised by the presence of a fibroblastic cell type which did not stain for alkaline phosphatase activity. This cell type was morphologically distinct from cell type A, formed by differentiation of EPL cells with bFGF, and is referred to as cell type B.
  • EPL cells revert to ES cells when cultured in the absence of MEDII but in the presence of LIF as assessed by morphology, gene expression, cytokine responsiveness and ability to contribute to chimaeras following blastocyst injection (Example 2).
  • ES cells were differentiated to EPL cells by culture in MEDII for 2 days, before passaging into medium containing LIF to form reverted EPL cells (EPL R ). Embryoid bodies were formed from each ES, EPL and EPL R cell population and their differentiation was compared.
  • Embryoid bodies derived from EPL R cells were identical in morphology to ES cell EBs and could be distinguished easily at day 4 from EPL cell EBs ( Figure 22; data not shown).
  • Expression of brachyury in ES and EPL cell EBs ( Figure 30A) was consistent with the profile previously described ( Figure 26).
  • Brachyury expression in EPL R cell EBs was similar to that observed for ES cell EBs, with expression detected at low levels on day 4 of development and not at high levels on day 2 and 3 as described for EPL cells.
  • EPL R EBs gave rise to visceral endoderm at levels 100
  • EPL cells can be controlled in vitro to generate cell types representative of specific embryonic germ layers, notably ectoderm and mesoderm.
  • These germ layer cells can be used for the generation of differentiated derivatives with potential for commercial, medical and agricultural use.
  • manipulation of environmental stimuli such as alteration of the extracellular matrix and/or the addition of exogenous soluble factors, can be used for efficient and programmed formation of alternative germ layers. Further manipulation of the environment will enable the directed formation of individual cell lineages from the germ layers, allowing the production of specified cell types and differentiation intermediates. Examples of this strategy are outlined below.
  • EBMs For the production of neurectoderm, EBMs (Example 1 ) were collected on day 4 and resuspended in DMEM + 50% MEDII with or without 20 ng/ml FGF4 99 comparable to ES EBs (31% and 46% respectively), as shown by wholemount in situ hybridisation.
  • Microscopic analysis of individually seeded ES, EPL and EPL R EBs ( Figure 30B,C) indicated that reversion of EPL to EPL R cells was accompanied by restoration of high levels of neuron formation and reduced levels and later appearance of beating cardiocytes. Reverted EPL cells therefore have a similar differentiation capacity to ES cells both in vitro and in vivo (Example 2).
  • EPL cell embryoid body formation therefore provides:
  • EPL cells generated in adherent culture Mesoderm was formed from EPL cells formed by adherent culture in the presence of MEDII as described in Example 1. These cells were trypsinised to a single cell suspension and seeded at a density of 1 x 10 5 cells/ml into bacterial plates to form EPL cell EBs as described in Example 6.
  • EPL cells formed in suspension (EBMs): EPL cells, formed as cell aggregates (EBMs) in suspension culture, were differentiated into mesoderm by trypsinisation to a single cell suspension and reaggregation in bacterial dishes in
  • ES and EPL cells were trypsinised and seeded in DMEM into bacterial grade petri dishes at a density of 1x10 5 cell/ml to allow aggregate formation.
  • approximately 100 aggregates from each plate were collected and seeded into 1.25ml MC media (0.9% methyl cellulose in Iscoves modified Dulbecco's medium (IMDM), 15% FCS, 50 mg/ml ascorbic acid, and 4.5x10 "4 M monothioglycerol (MTG)) supplemented with 400 U/ml IL-3 (courtesy of Dr. T. Gonda, IMVS, Sydney) and 10 ng/ml recombinant human M-CSF (R&D Systems).
  • IMDM Iscoves modified Dulbecco's medium
  • FCS fetal ascorbic acid
  • MMG monothioglycerol
  • Macrophages were identified by morphology when stained with May-Gr ⁇ nwald-Giemsa stain, and by positive staining with the macrophage-specific antibody F4/80 (Austyn and Gordon, 1981 ).
  • Sox1 riboprobes for wholemount in situ hybridisation were generated from plasmid #1022 (obtained from Dr. Robin Lovell-Badge, NIMR, London) linearised with BamHI and transcribed with T3 RNA polymerase (anti-sense) or linearised with Hindlll and transcribed with T7 RNA polymerase (sense).
  • Antisense Sox1 probes for RNase protections were generated from a plasmid containing a -450 bp XhoMEcoR fragment from the Sox1 cDNA in plasmid #1022 subcloned into pBluescript II KS+. The resulting plasmid was linearised with Kpn and transcribed with T7 RNA polymerase.
  • Sox2 probes for use in in situ hybridisation were generated from plasmid #1015 (obtained from Dr. Robin Lovell-Badge, NIMR, London) linearised with Acc ⁇ and transcribed with T3 RNA polymerase (antisense) or linearised with Not! and transcribed with T7 RNA polymerase (sense).
  • An anti-sense Gbx2 riboprobe for use in in situ hybridisation were generated from pGbx2c7.1 (Chapman et al., 1997) linearised with Alu ⁇ and transcribed with T3 RNA polymerase.
  • Seeded cellular aggregates were fixed in 4% paraformaldehyde in PBS and blocked in the appropriate blocking buffer for 30 minutes followed by overnight incubation with primary antibodies in blocking buffer at 4°C. Aggregates were then rinsed with species specific secondary antibodies in blocking buffer for 1 hour. For FITC-conjugated secondary antibodies, propyl gallate 5 mg/ml was added. Slides were examined on a Nikon TE300 microscope using fluorescence.
  • Blocking buffer 1 % goat serum, 1 mg/ml BSA, 1 % Triton X 100 in PBS.
  • Primary antibody Developmental Studies Hybridoma Bank, reference Rat 401 , used at a dilution of 1 :100.
  • Secondary antibody FITC conjugated goat anti- mouse IgM ( ⁇ -specific: Sigma) used at a concentration of 1 :100.
  • N-Cam Blocking buffer: 1 % FCS, 1 mg/ml BSA, 1 % Triton X 100 in PBS.
  • Primary antibody Santa Cruz Biotech, SC-1507 used at a concentration of 1 :20.
  • Secondary antibody FITC conjugated rabbit anti-goat IgG (Sigma) used at a dilution of 1 :700.
  • NF200 was detected by indirect immunofluorescence as described by Robertson (1987).
  • Primary antibody anti-neurofilament 200 (Sigma Immunochemicals N-4142) used at a dilution of 1 :200.
  • Secondary antibody FITC-conjugated anti-rabbit IgG (Silenus) used at a dilution of 1 :60.
  • EBMs formed by aggregating ES cells in DMEM + 50% MEDII for 4 days in suspension culture (Example 1 ), were maintained in DMEM + 50% MEDII, or DMEM + 50% MEDII + 20 ng/ml FGF4 for a further 3 days in suspension. Under these conditions approaching 100% of EBMs developed into cellular aggregates with a distinctive layered structure of pseudo-stratified epithelial appearance (Figure 31 A). These layers were observed in aggregates cultured in 50% MEDII alone but were enhanced in the presence of FGF4. However, these layers were never seen in EPL cell EBs, and were observed only sporadically in ES cell EBs where they comprised a subset of cells within the body.
  • Sox1 is first expressed by the neurectoderm/neural plate in vivo and by all undifferentiated neural cells. It is not expressed in cell types of mesodermai or endodermal origin. Gbx2 is expressed in the primitive streak, then in the neurectoderm prior to neural tube closure and subsequently at the midbrain/hindbrain boundary. Sox2 is expressed in the neurectoderm after neural tube closure and persists until terminal differentiation of neural cells. In situ hybridisation demonstrated widespread expression of Sox1 by cells within the layers, and Gbx2 by a subset of these cells. This suggested that the cell type produced by these culture conditions was equivalent to neurectoderm, specifically early neural plate around the time of neural tube closure.
  • Sox1, Sox2 and Gbx2 The analysis of neural gene expression within these aggregates was refined by analysis of neural specific markers by in situ hybridisation (Sox1, Sox2 and Gbx2; Figure 32A) and immunohistochemistry (nestin and N-CAM; Figure 32B) on days 8, 9 and 10.
  • Sox1 expression was detected in greater than 90% of aggregates on day 8 of development, however, expression was seen in only a proportion of cells in each aggregate. Sox1 expression increased on day 9 and 10 of development, with approaching 100% of cells within each aggregate expressing Sox1. Similarly, on day 10 the majority of cells were also expressing Sox2.
  • Gbx2 expression was observed in a proportion of cells on day 8 of development and was down-regulated on days 9 and 10. This expression pattern is consistent with identification of the cell layers as neurectodermal in origin.
  • N-Cam is a marker expressed by all neural lineages, including both undifferentiated and differentiated cells. N-Cam staining was detected throughout the aggregates on days 8, 9, and 10, with the number of cells expressing N-Cam increasing to nearly 100%. N-Cam was expressed both in the cell layers and in differentiated cells surrounding the layers, indicating that the majority of the differentiated cells were of neural origin.
  • Sox1 expression (Figure 33B) were detected by RNase protection in aggregates formed from EBMs on days 6, 7 and 8. While expression of Gbx2 decreased on day 8, Sox1 expression continued to increase to day 10.
  • pluripotent cells can be programmed specifically to an ectodermal and neurectodermal fate by factors within MEDII.
  • the ectodermal cells are formed in the absence of mesodermai cell types, and exhibit a temporal pattern of gene expression equivalent to neurectoderm in vivo, with progression from an early neurectodermal cell type equivalent to neural plate, to a later neurectodermal cell type present after neural tube closure. In the embryo these cells are precursors for all neural lineages.
  • Neurectoderm derived by directed pluripotent cell differentiation in vitro can be further differentiated to neural cell types.
  • Neurectoderm formation in vivo proceeds via the formation of definitive ectoderm.
  • definitive ectoderm Although no markers exist for definitive ectoderm in vivo, gene expression analysis identified a population of cells in EBMs programmed to form neurectoderm which expressed low levels of Oct4 and failed to express neurectodermal markers. These cells were present transiently between primitive ectoderm (high Oct4 expression) and neurectoderm (high Sox1, Gbx2) and suggest that neurectoderm formation proceeds via an intermediate population which may represent definitive ectoderm.
  • neurectoderm described here does not rely on the addition of chemical inducers, such as retinoic acid, or genetic manipulation to promote neural formation. Instead, it relies on biologically derived factors found within the conditioned medium MEDII. Neural progenitors formed in this manner are thought to be differentiated from pluripotent cells in a manner analogous to the formation of neural cells during embryogenesis and are therefore ideal for the production of differentiated neural cells useful for commercial, medical and agricultural applications. Further, in contrast to the formation of limited neural lineages by chemical inducers such as retinoic acid, the identity of neural cell types produced using these methodologies is not likely to be restricted.
  • Neurectoderm programming of pluripotent cell differentiation requires the large molecular weight components, but not the small molecular weight components, of MEDII.
  • EPL cells were formed by culturing ES cells for 2 days in the presence of
  • EPL cell EBs were formed in DMEM or DMEM
  • EPL cell EBs formed beating muscle with high efficiency in the absence of the large molecular weight component and none of these EBs contained neurons. Inclusion of the large molecular weight component (50-100 ⁇ g/ml) during embryoid body formation resulted in the development of neural cells in about 5% of the EBs at day 9, and in 10-12% at d 10 and 12. Only 10-12% of EPL cell EBs formed in the presence of the large molecular weight component contained beating muscle, and the formation of beating muscle was delayed until day 9. These experiments were carried out in the presence of 1 ug/ml neutralising anti-human LIF antibody (R&D Systems). The altered developmental program could therefore not be attributed to low levels of LIF expressed by the Hep G2 cells.
  • R&D Systems neutralising anti-human LIF antibody
  • This experiment demonstrates a role for the large molecular weight component of MEDII, and possibly ECM components, in programming of differentiation within pluripotent cell aggregates so as to delay and reduce mesoderm formation, and promote the formation of neurons.
  • Pluripotent cells can be programmed to adopt a specific mesodermai fate by differentiation through a homogeneous EPL cell intermediate as shown in Example 6. This may reflect the absence of visceral endoderm within EPL cell EBs. Nascent mesoderm formation can be detected in approaching 100% of EPL cell EBs and is probably underestimated by scoring beating cardiocytes which comprise only one of the possible nascent mesoderm cell fates.
  • the previous experiments were carried out using EPL cells formed from ES cells in adherent culture.
  • Alternative methodologies for efficient mesoderm formation from pluripotent cells in vitro Formation of mesoderm by reaggregation of EPL cells formed in suspension
  • EPL cells formed in suspension in the presence of MEDII comprise a stable and homogeneous population of cells with properties equivalent to embryonic primitive ectoderm. Programming the differentiation of these cells to a mesodermai fate is thought to require both removal of the neurectoderm-inducing activity of MEDII and dissociation from ECM components. This would mimic the behaviour of pluripotent cells destined to form mesoderm during primitive streak formation in vivo.
  • Brachyury expression could not be detected in reaggregates developed in DMEM + 50% MEDII, consistent with the fact that these are destined to form neurectoderm.
  • Brachyury expression indicating mesoderm formation, was strongly up regulated in reaggregates developed in DMEM at day 2 and 4 in the absence of FGF4.
  • FGF4 brachyury expression peaked on day 2 and was down regulated by day 4, suggesting that addition of FGF4 resulted in accelerated mesodermai differentiation of the pluripotent cells.
  • the expression of marker genes was confirmed by in situ hybridisation of reaggregated bodies with Oct4 and brachyury specific probes (data not shown). These data indicate that EPL cells formed in suspension can be programmed to differentiate into mesoderm.
  • Mesodermai precursors derived by directed pluripotent cell differentiation can be programmed to alternative developmental fates
  • Example 6 To establish whether the elevated levels of nascent mesoderm in EPL cell EBs were developmentally restricted to myogenic lineages or could be programmed to alternative developmental fates, the formation of macrophages in response to exogenous cytokines was assessed.
  • EPL cell and control ES cell EBs were differentiated in MC media supplemented with mlL-3 and hM-CSF, and scored for the presence of macrophages on days 12, 15 and 18 (Figure 37).
  • On day 12 32.4% of EPL cell EBs were observed to contain macrophages, compared to 4.8% of ES cell EBs.
  • On days 15 and 18 the proportion of embryoid bodies containing macrophages had increased to 43% of EPL cell EBs and 9-10 % of ES cell EBs. Consistent with the earlier formation of mesoderm in EPL cell EBs, formation of macrophages initiated approximately two days earlier in these embryoid bodies compared to ES cell EBs (data not shown).
  • Pluripotent cell differentiation can be specifically programmed to the formation of alternative mesodermai and ectodermal lineages
  • EPL cell EBs formed beating muscle with high efficiency but were unable to form neurons.
  • EBMs showed the reciprocal pattern, forming neurons with high efficiency but failing to form beating muscle.
  • the formation of mesoderm in particular is probably underestimated in this analysis because only a single mesodermai cell type, beating muscle, was scored.
  • Appropriate use of the factors within MEDII to form and differentiate pluripotent cell populations can therefore be used to direct specific formation of alternative mesoderm and ectoderm germ layers from pluripotent cells in vitro. Summary
  • pluripotent cells were obtained by culture of ES cells in MEDII, we envisage that primary pluripotent cells isolated from embryonic ICM, primitive ectoderm or PGCs, or pluripotent cells obtained by dedifferentiation or nuclear transfer, could be used as a source of material for controlled lineage specific differentiation in vitro.
  • Neurectoderm formation in the absence of mesoderm formation, occurred when EPL cells were differentiated in the presence of MEDII in suspension culture. This suggested that the conditioned medium contained components required for neural determination. Fractionation of the conditioned medium suggested that this component resided in a fraction containing medium components of greater than 10 kDa, and may be the ECM component identified as active in the formation of EPL cells. Formation of neurectoderm from primitive ectoderm in contact with ECM components is consistent with the determination of this lineage during embryogenesis.
  • Efficient formation of mesoderm from EPL cells, in the absence of neurectoderm, could be achieved in adherent or suspension culture and required removal of MEDII, potentially to eliminate contact with ECM proteins. This could be achieved by aggregating, or reaggregating, EPL cells in medium without the addition of MEDII, or seeding EPL cells onto gelatin treated plastic-ware in the presence of members of the TGF ⁇ or FGF families. Differentiation of EPL cells as cellular aggregates proceeded in the absence of visceral endoderm and resulted in the formation of mesodermai cell lineages, as assessed by gene expression and terminal differentiation.
  • EPL cells and the inclusion or withdrawal of MEDII or MEDII activity, provide an approach for the production cell populations highly enriched in progenitor and differentiated cells derived from a single germ layer.
  • This approach does not involve the addition of chemical inducers (such as retinoic acid for neural cell formation) or prior genetic modification of the pluripotent cells. Instead it relies on the factors thought to be involved in neurectoderm and mesoderm formation during normal embryonic development in vivo. Progenitors derived in this manner are ideal for projected applications in human medicine, veterinary applications and agriculture.
  • the utility of the present invention in gene therapy is as follows. I depends on using nuclear transfer technology that has already been developed and used in several animal species, including sheep, cattle and mice. A donor human egg is fertilised in vitro, but then the nucleus removed and replaced by a nucleus from a cell from the recipient of the intended gene therapy. The nuclear transferred egg is allowed to develop into an early embryo in vitro, and then cells from it are used to generate, using the procedures and products of this invention, an EPL or ES cell line.
  • This cell line is then genetically modified, using DNA transfer technology known to those skilled in the art, to correct a genetic defect, or to replace or add a functioning copy of a desired gene; (examples; clotting factor genes for hemophelia, the CF gene for cystic fibrosis, the insulin gene for Type 1 diabetes).
  • the modified ES or EPL cell line is then differentiated in vitro to a desired cell, tissue or organ, which is reintroduced into the recipient in a therapeutic transplantation procedure. Since all the genes of the modified cell line (with the exception of the modification or the introduced gene) are identical to the recipient individual's own genes, there is unlikely to be cell or tissue rejection, since this would be in effect, a perfectly matched transplant.
  • the modified cells from a non-matched human ES or EPL cell line are genetically modified and then encapsulated, by cell encapsulation techniques known to those skilled in the art. They are then introduced to a recipient as an implant to produce in that individual, a gene product (e.g. clotting factor, insulin, etc.,) missing or defective in the treated individual. It is also possible to genetically modify a donor established ES or EPL cell line to render it non-immunologic to any recipient, thereby generating a "universal ES or EPL cell line". This cell line is further modified to use in the therapeutic procedures described above, without the use of encapsulation technology.
  • Such "universal" donor cells are used to generate human endothelial cells, that are used in xenotransplantation procedures, for example, to coat xenotransplant organ blood vessels; e.g. pig kidneys or hearts, with human endothelium, to reduce or eliminate delayed graft rejection.
  • neural cell transplantation As a long-term therapy and cure for neurological disorders, significant practical hurdles remain. Allogeneic and xenogeneic transplants are still subject to rejection even though immunological protection is afforded by the blood brain barrier. Furthermore the availability of foetal cells, often used in neural transplantation trials, is scarce. Neural cells, including neural stem cells developed by controlled differentiation in vitro of pluripotent cells along defined neural pathways offers an ideal source of cells for neural cell therapy and neural transplantation.
  • neural cell transplantation may also offer benefits to neurodegenerative disorders.
  • transplantation with neural cells derived from pluripotent cells can be investigated in a mouse model. Differentiation of ES cell lines expressing ⁇ -galactosidase directed to a nuclear location (KSF4 cell line) or to the cytoplasm (ROSA 26 cell line) can be directed along the neural pathway using MEDII as described herein. Neurectoderm or differentiated neural cells can be injected into cerebral vesicles of neonates.
  • transplanted cells survival of the transplanted cells is indicated by the maintenance of cells expressing ⁇ -galactosidase in the brain.
  • the ability of transplanted cells to integrate can be determined by investigating the connections established by marker cells expressing the cytoplasmic form of ⁇ -galactosidase (ie cells derived from the ROSA 26 ES cell line).
  • Rex1 a gene containing zinc finger motifs, is rapidly reduced by retinoic acid in F9 teratocarcinoma cells. Mol. Cell Biol. 9, 5623-5629.
  • Neoplastic differentiation charcteristics of cell lines derived from murine teratocarcinoma. J. Cell. Physiol. 84, 13-28.
  • Nkx 2.5 a novel murine homeobox gene expressed in early heart progenitor cells and their myogenic descendants. Development 119, 419-431.
  • the murine H19 gene is activated during embryonic stem cell differentiation in vitro and at the time of implantation in the developing embryo. Development 113, 1105-1114.
  • Oct-4 a germline-specific transcription factor mapping to the mouse t-complex. EMBO J. 9, 2185-2195.

Abstract

La présente invention concerne un facteur biologiquement actif capable d'influer sur la différentiation, la prolifération et/ou la conservation des cellules multipotentes. L'invention se rapporte également à des procédés d'utilisation du facteur biologiquement actif visant à produire des cellules multipotentes, des cellules multipotentes possédant des propriétés différentes et plus particulièrement des cellules précoces du type d'ectoderme primaire (cellules EPL). L'invention concerne aussi des cellules multipotentes et des cellules partiellement ou définitivement différenciées ainsi que leur utilisation en thérapie génique et dans celle des cellules humaines ainsi que dans la fabrication d'animaux transgéniques.
PCT/AU1999/000265 1998-04-09 1999-04-09 Facteur de differentiation/de proliferation et de conservation des cellules et procedes d'utilisation correspondants WO1999053021A1 (fr)

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WO2006020919A2 (fr) 2004-08-13 2006-02-23 University Of Georgia Research Foundation, Inc. Compositions et procedes d'auto-renouvellement et de differentiation dans des cellules souches embryonnaires humaines
ES2800973T3 (es) * 2004-09-28 2021-01-07 Wisconsin Alumni Res Found Cultivo de células madre embrionarias de primates
AU2006262329B2 (en) 2005-06-22 2011-04-07 Asterias Biotherapeutics, Inc. Differentiation of primate pluripotent stem cells to cardiomyocyte-lineage cells
CN105802904B (zh) 2006-02-23 2021-04-20 维亚赛特公司 用于培养可分化细胞的组合物和方法
AU2007321928A1 (en) 2006-11-24 2008-05-29 Regents Of The University Of Minnesota Endodermal progenitor cells
US8623650B2 (en) 2007-10-19 2014-01-07 Viacyte, Inc. Methods and compositions for feeder-free pluripotent stem cell media containing human serum
US9329169B2 (en) * 2007-10-29 2016-05-03 University Of Georgia Research Foundation, Inc Vivo isotopic labeling method for quantitative glycomics
EP2229435B1 (fr) * 2007-12-06 2016-03-02 Agency for Science, Technology And Research Procédé permettant la différenciation et la prolifération induites par matrice extracellulaire de cellules souches
US10227563B2 (en) 2008-06-06 2019-03-12 Riken Method for culture of stem cell
US8008075B2 (en) 2008-11-04 2011-08-30 Viacyte, Inc. Stem cell aggregate suspension compositions and methods of differentiation thereof
DK2356213T3 (da) 2008-11-04 2019-09-09 Viacyte Inc Stamcelleaggregatsuspensionssammensætninger og fremgangsmåder til differentiering deraf
US8895300B2 (en) 2008-11-04 2014-11-25 Viacyte, Inc. Scalable primate pluripotent stem cell aggregate suspension culture and differentiation thereof
JP5115530B2 (ja) * 2009-09-18 2013-01-09 ユーハ味覚糖株式会社 神経新生促進剤を含有する飴、グミまたは飲料
WO2011055855A1 (fr) 2009-11-05 2011-05-12 Riken Procédé d'induction d'une différenciation dans des cellules souches cultivées
AU2013248265B2 (en) 2012-11-08 2018-11-01 Viacyte, Inc. Scalable primate pluripotent stem cell aggregate suspension culture and differentiation thereof
AU2014225352B2 (en) 2013-03-07 2017-02-09 Viacyte, Inc. 3-dimensional large capacity cell encapsulation device assembly
EP3290510A1 (fr) * 2016-08-31 2018-03-07 Rheinisch-Westfälische Technische Hochschule (RWTH) Aachen Kit de modèle de lignées de cellules en suspension
CN110431226B (zh) * 2017-01-05 2024-03-12 新加坡科技研究局 产生肝巨噬细胞的方法及其用途
WO2018185260A1 (fr) * 2017-04-06 2018-10-11 Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt (GmbH) Nouvelle matrice dérivée d'hépatocytes humains pour la différenciation de cellules souches et la réparation de tissus
US20190167724A1 (en) * 2017-12-04 2019-06-06 Caire Medical-Biotechnology International Co. Neuroprotective composition, preparation process thereof and medical uses thereof
CN114807005B (zh) * 2022-04-09 2023-11-21 翌圣生物科技(上海)股份有限公司 使用动物尸体制备基质胶的方法

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5453357A (en) * 1992-10-08 1995-09-26 Vanderbilt University Pluripotential embryonic stem cells and methods of making same
US5405772A (en) * 1993-06-18 1995-04-11 Amgen Inc. Medium for long-term proliferation and development of cells
US6331406B1 (en) * 1997-03-31 2001-12-18 The John Hopkins University School Of Medicine Human enbryonic germ cell and methods of use

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10465162B2 (en) 2004-04-27 2019-11-05 Viacyte, Inc. Anterior endoderm cells and methods of production
US9132226B2 (en) 2008-11-14 2015-09-15 Viacyte, Inc. Encapsulation of pancreatic cells derived from human pluripotent stem cells
USD755986S1 (en) 2013-03-07 2016-05-10 Viacyte, Inc. Cell encapsulation device
US11623023B2 (en) 2016-11-10 2023-04-11 Viacyte, Inc. PDX1 pancreatic endoderm cells in cell delivery devices and methods thereof

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