MXPA00010079A - Lineage specific cells and progenitor cells - Google Patents

Abstract

A method for generating a culture that is purified or enriched in respect of cells of a selected lineage is described in which a selectable marker, which is differentially expressed in cells of the selected lineage compared with its expression in other cells, is introduced into a multipotential cell and the multipotential cell is cultured to induce differentiation of the multipotential cell into a cell of the selected lineage or into a mixture of cells including cells of the selected lineage, or is cultured to induce preferential survival of cells of the selected lineage. Those cells that express the selectable marker are then selected for. Progenitors of selected lineage are also described as is the use of the method in assay techniques.

Description

SPECIFIC LINEAGE CELLS AND PROGENITOR CELLS FIELD OF THE INVENTION -5 This invention relates to cells of specific lineage and progenitor cells, the methods to obtain them and their uses. Embryonic germ cells (ES) plur ipotent can be induced to differentiate in vi t ro in a mixture of cell types, comprising the ™ Embryonic yolk sac and derived from the three embryonic germ layers. However, the disorganized and heterogeneous nature of differentiation prevents manipulation and analysis of the individual lineages. In particular, the invention provides a technique of genetic selection of specific lineage to establish purified populations of natural precursors by differentiating ES cells. BACKGROUND OF THE INVENTION Embryonic germ cells (ES) are lines of untransformed cells derived directly from the pluripotent founder tissue in the mouse or human embryo, the epiblast (Evans and Kaufman, 1981, Martin, 1981, Brook and Gardner, 1997, Thomson et al, 1998, Shamblott et al., 1998). ES cells can be propagated and manipulated genetically extensively while maintaining the capacity for multilineage differentiation, both in vitro and in vitro (Robertson, 1987). The differentiation of ES cells in culture reflects in detail the differential events in the embryo. Therefore, in At the beginning, ES cells provide i n ™ IV access to the instructive and selective processes by which cell di ffi cation is generated in the mammalian embryo (Smith, 1992). The multilineage differentiation of ES cells can be initiated by simple aggregation (Martin and Evans, 1975; Doetschman et al., 1985). Aggregates form structures known as embryoid bodies, whose differentiation reflects aspects of the embryogenesis of peri- and early postimplantation mice (Martin et al., 1977, Doetschman et al., 1985). A diverse array of cell types was found in excrescences derived from the embryoid bodies (Weiss and Orkin, 1996). Although the Representation of 11na3% s in particular can be reduced or improved by treatment with dimethyl sulfoxide or retinoic acid (RA), the differentiated products always consist of a mixture of cell types. Intrinsic disorganization and complexity have limited the exploitation of cell differentiation ES11 vi t ro for the assignment of genetic functions in development trajectories. Several reports have documented the presence of neuronal cells and glia (Bam, 1995, Fraichard et al., 1995, Strubmg et al., 1995, Okabe et al., 1996) in embryoid body excrecences. This could be exploited to detect, characterize and manipulate the factors that regulate neurogenesis and glial differentiation. ES cells could also be used as a source of normal or genetically engineered neural cells for biochemical and functional studies or for transplants. However, the problem is that these objectives are severely compromised by the abundance of non-neural cells in the crops and because it is not possible concurrently to maintain or maintain a culture predominantly containing progenitors of neural cells. Accordingly, the technique fails to provide a reliable method for obtaining a substantially pure population of a cell of any selected lineage, and progenitor cells of a particular selected lineage. The technique also fails to provide assays for developmental influences and other influences of factors on the progenitor cells of differentiated cells of a selected lineage.

BRIEF DESCRIPTION OF THE INVENTION The present invention aims to provide cells and / or cells differentiated from a selected lineage, assays for the influence of factors on such cells and uses of these cells, such as in transplants. The present invention also aims to provide a genetic selection technique for removing non-neural cells from cultures and for allowing the purification of embryoid bodies from competent neural precursors of differentiation. The present invention provides a method for obtaining a cell culture of a selected lineage having a combination of two steps. One step is to select the cells that express a genetic characteristic of cells of that lineage. The other is to cultivate such cells that tend to differentiate into or proliferate as cells of that lineage. The effect is to deliver a more highly purified culture of the selected lineage cells than otherwise possible. By way of example, one step of the combination is to select cells expressing a gene known to be expressed only in hematopoietic progenitor cells, and the other is to grow cells in a medium containing a nutrient known to promote differentiation of cells in hematopoietic progenitors.

DETAILED DESCRIPTION OF THE INVENTION In accordance with the foregoing, the invention provides a method for generating a a culture that is purified or enriched with respect to the cells of a selected lineage, comprising: (i) introducing into a 5 ippotential cell a selectable marker that is expressed differentially in cells of the selected lineage compared to its expression in 10 other cells; • (ii) cultivate the mult ipotential cell to induce (a) the differentiation of the ipotential muI t cell in a cell of the selected lineage or in a cell mixture that is or that includes cells of the selected lineage or i (b) the preferential survival of cells of the selected lineage; and (iii) select those cells that express the marker capable of being selected, The method is suitable to obtain cells, optionally progenitors, of the lineage selected at a high level. However, following the method of the art for inducing the differentiation of ES cells in a culture including neural cells, a maximum of about 50% of neural progenitors can be provided, using the technique of the invention an excess purity can be obtained 70%, and in a specific modality described below the purity is substantially of 100%. • Step (ii) results in a pure population of cells or a mixed culture at least slightly purified or enriched with respect to the desired cells and can be carried performed in a suitable manner when culturing the mult ipotential cell in the presence of a factor that induces the differentiation of the cell in a progenitor cell of the selected lineage. By means of the example, a specific mitogen for neural progenitors is the fibroblast growth factor. The reference herein to the term "factor" is not intended to be limited to protein or polypeptide factors but is intended to encompass any biologically active molecule or molecule biologically potentially active The ipotential cell can be selected from embryonic germ cells (ES), embryonic germ cells (EG), 5 embryonal carcinoma (EC) cells, a primary culture of fetal cells, a primary culture of postnatal cells and a culture. primary of adult cells. The method may also comprise cells genetically modified to eliminate, mutate, replace or add genes with ™ object to test for genetic functions in the progenitor cells of the selected lineage or to adapt a cellular phenotype to make it more suitable for transplants. Therefore, The cells can be obtained by introducing a marker capable of being selected into an ipotial muI t cell line or a primary culture containing the cells of interest and then selecting the cells of interest. He The marker capable of being selected is optionally introduced by transfection or viral infection by means of a transgenic animal from which the primary cultures are then established, suitably using the methods described in WO-A- 9 4/2 4 2 7 4. Accordingly, the invention allows a highly enriched population of cells to be sold, and in particular all I. lineages of populations of a selected lineage to be obtained. In an example below the population obtained is substantially 100% pure making it possible to isolate a single cell from the lineage of the known parent. The invention is applicable to all lineages of the I cells, particularly the progenitor cells. A marker capable of being selected expressed in cells expressing a Sox gene leads to cells neural progenitors; the CD34, CD44 and SCL genes are suitable for obtaining hematogenous progenitors, and the Nkx 2.5 or GATA-4 gene for cardiac progenitors. To generate myogenic progenitors, MyoO or myE5. The use of retinoic acid induces the differentiation of ES cells in neural cells, DMSO induces differentiation in hematopoietic cells and the absence of retinoic acid induces a population enriched in cardiac progenitors.

The method optionally further comprises: (iv) introducing a second marker capable of being selected into the target cell that is differentially expressed in progenitor cells or other cells of a selected sub-lineage as compared to its expression in other cells, wherein the cells of the selected sub-lineage are formed by the differentiation of cells from the selected progenitor lineage; and (v) when a culture of progenitor cells of the selected lineage has been obtained, allow or induce the differentiation of the cells and select the cells expressing the second marker capable of being selected.

This aspect of the invention further enriches the purity of the cell culture obtained, and is of advantage in cases where cells of the selected lineage differentially express a gene but also at a slightly different level of unwanted cells. In a preferred embodiment of the invention, described below in more detail, the marker capable of being selected is a gene that codes for the antibiotic resistance and for selecting those cells that express the marker with ^ ability to be selected comprises introducing the antibiotic into the culture In use, the application of the antibiotic selectively removes or removes the cells that do not express the marker, leaving behind a population of purified or enriched cells with respect to those that express the | antibiotic resistance, that is, viable cells of selected lineage. At least two days for the introduction of the marker capable of being selected are known and suitable for the invention. The marker with the ability to be selected can be introduced into the ipotential cell by integration target or gene retention to a gene that expresses differently in the progenitor cells of the selected lineage. The expression of the selectable marker is operably linked to a gene that is differentially expressed in a desired pattern. The marker capable of being selected can also be introduced into the mult ippotential cell by means of random integration as a transgene in which it is expressed under the control of regulatory elements of a gene that is expressed di fferentially in progenitor cells of the selected lineage. The marker capable of being selected may be more generally a marker than when expressed, the results in the preferential survival of cells expressing the marker, with antibiotic resistance being such an example. The marker capable of being selected may also be a marker whose expression results in a preferential elimination of cells expressing the label. In this instance, the marker is expressed in cells different from those of the selected lineage. In a specific modality of the invention described in an example below, the mult ippotential cell is an ES, EC or EG cell and the method comprises inducing the differentiation of the ipotential muI t cell - one method is to form an embryoid body from the cell - and disassociating the cells In one example trypsin is used. It is an advantage that individual cells are obtained in this way. These remain exposed to the culture medium and not attached to the neighboring cells are free of cell-to-cell influences that could affect the growth pattern and / or differentiation of the cells, and inhibit the formation of progenitor cells according to the invention . A culture that is purified or enriched with respect to the ventral progenitor cells is obtainable according to the invention, wherein the marker capable of being selected is differentially expressed in the neural progenitor cells and the second marker capable of being selected is expressed diferentially in the ventral progenitor cells. The second marker with the ability to be selected for this is expresses differentially in the cells expressing Pax 6. A culture that is purified or enriched with respect to the dorsal progenitor cells is obtainable according to the invention, wherein the marker capable of being selected is expressed differentially in the Neural progenitor cells and the second marker with ability to be selected is expressed differentially in the dorsal progenitor cells. The second marker capable of being selected for this is differentially expressed in cells expressing Pax 3. The invention also provides a cell, preferably a progeny, of a selected lineage, obtainable according to the method of the invention. Until now, the preparations of the offspring were too impure for certainty in that any selected cell was a progemtora cell. With the culture according to the invention that can give rise to preparations of substantially 100% pure progenitors, the isolation of a progenitor is achieved simple . The invention further provides a composition comprising a plurality of cells, wherein a majority of the cells are progenitor cells of a selected lineage. Preferably, at least 60% of the cells are progenitor cells of the selected lineage. More preferably, at least 60% of the cells are neural progenitor cells. In addition, the invention provides an isolated neural progenitor cell. A significant application of the invention is found in the field of test factors for the influence that a selected progenitor can have. In accordance with the foregoing, the invention still further provides an assay for the influence of a factor on a culture of progenitor cells of a selected lineage, comprising: (i) introducing into a mult ippotential cell a marker capable of being selected which is expressed differentially in cells of the selected lineage compared to its expression in other cells; (ii) culturing the ipotential mu ti t cell to induce differentiation of the mult ipotential cell into a cell or mixture of cells of the selected lineage that includes cells of the selected lineage or to induce the preferential survival of cells of the selected lineage; and (iii) selecting those cells that express the marker capable of being selected; (iv) culturing the cells in this manner obtained from the selected lineage in the presence of the factor. The test method is preferably for testing the influence of a factor in a culture of progenitor cells of selected lineage, wherein the marker capable of being selected is differentially expressed in those progenitor cells. The reference A "factor" in this assay is intended to be a reference to any current molecule or biologically potentially active molecule that can be introduced into cell culture of the I 5 selected lineage, and therefore is not intended to be limited to protein or polypeptide factors. The term is also intended to encompass a gene introduced or modified in a mult ipotential cell from which the lineage selected. Accordingly, the assay can conveniently be used for the influence of a particular gene, as well as for the influence of polypeptide and / or proteinic or small factors molecules of interest. The method can be used to test whether the factor has a proliferating, maturing, toxic or protective influence on the progenitor cells of the selected lineage, or if a factor has a proliferating, maturing, cytotoxic or protective influence of glial in the neural progenitor cells or in other cells differentially obtained after the withdrawal of selection and differentiation of the progenitors.

An advantage is the test method that allows a population of terminally differentiated cells of the selected lineage to be obtained and used for such tests as genetic and drug discovery filters. A neural progenitor cell, or a culture comprising a majority of neural progenitor cells, for transplants is still also provided by the invention. In an example described below, a neural progenitor cell of the invention has been isolated and successfully transplanted to the brain of a rat. The neural cell may optionally be a neuronal cell or a glial cell. This transplantation can also be carried out using neuronal cells obtained from neural progenitors of the invention. A suitable method for generating purified neurons comprises obtaining a purified culture with respect to the neural progenitors, using the method of the invention wherein the selectable marker is expressed differentially in cells expressing a Sox gene, and cultivating the progenitors obtained in the presence of a suitable medium for the differentiation of progenitors in neurons. A suitable method k to generate purified glial cells P5 comprises obtaining a purified culture with respect to the neural progenitors, using the method of the invention wherein the marker capable of being selected is expressed substantially in cells expressing a gene Sox, and to cultivate the progenitors obtained in the presence of a suitable medium for the differentiation of progemtoras in glial cells. It is still provided by the Invention a neural progenitor for transplantation in order to treat neurodegenerative diseases or neuronal / brain damage, neural progenitor cells for transplantation, obtainable from a cell selected from an ES cell, an EC cell, an EG cell, a primary culture of fetal cells and a primary culture of post-natal cells, for transplantation in order to treat neurodegenerative diseases or damage neuronal / cerebral, a method of treatment of neuroprotective diseases or neuronal / brain damage comprising the transplantation of a neural progenitor cell, and a method for preparing a neural progenitor cell or a differentiated progeny thereof for storage, which comprises obtaining the cell in a method of agreement. with the invention and freeze the cell in the presence of a ciroprot ector, such as dimethyl sulfoxide at 10%. In one embodiment of the invention, a selection / reporter gene, ßq e, was integrated by homologous recombination in the sox2 gene, which is expressed uniformly in cells precursors in the neural plate and the neural tube. The application of G418 to the cultures to differentiate the cultures of the sox2 target cells resulted in the efficient isolation of the viable Jgeo positive cells. These cells expressed markers of neuroepithelial precursor cells. They differed effectively in networks of neuron-type cells that expressed a variety of neuronal markers. Accordingly, it is provided by the invention a m vi t ro system for genetic and molecular dissection of mammalian neural differentiation, and also a trajectory for the production of pure populations of - genetically modified neural precursors or P5 normal and neurons for functional studies including transplants. In addition, the lineage selection approach of the invention is applicable to the isolation of other precursor populations by differentiating the cultures of ES cells. The invention further provides a method for amplifying a purified population of the progenitor cells of a selected lineage, which comprises maintaining the cells in culture in the presence of a mitogen; and a growth factor. Progenitor cells comprise Preferably a genetic coding for a marker capable of being selected, whose gene is expressed differentially in progenitor cells as compared to its expression in other cells, and the method further comprises selecting the cells that they express the marker with the ability to be selected. It is an option to maintain the crop on a plurality of generations and ^ periodically select the cells that P 5 express the marker with the ability to be selected. Another option is to maintain the culture over a plurality of generations and continuously select the cells that express the marker capable of being selected. Where the marker capable of being selected is of antibiotic resistance, the method may comprise continuous culture in the presence of antibiotic. DESCRIPTION OF THE DRAWINGS The invention is now described with reference to the accompanying drawings in which: - Figure 1 shows the morphology and characterization of neurons and glia in 4-day cultures; Figure 2 shows the phase contrast photograph of day 0 cells (2a-4 25 hours after plating), and dyeing of Soxl antibodies (2b) - the graphic scale is 50 microns; Figure 3 shows a schematic diagram of the lineage selection according to the invention; Figure 4 shows the culture enrichment for Sox2 positive cells by selection of G418; Figure 5 shows the expression of specific region neural precursor markers; Figure 6 shows proliferating Sox2-positive cells i n vi t ro in response to FGF-2; Figure 7 shows neurons derived from ES cells differentiated after the selection of S ox2; Figure 8 shows the results of the sonar dredge influence test on the neural progenitors; and Figure 9 shows a neuron derived from ES cells after in utero transplantation. In more detail, Figure 1 shows the morphology and characterization of neurons and glia in 4-day crops. E14TG2a ES cells were induced to differentiate into 8-day aggregates, plated on poly i-D-1 i sina / laminin substrate in DMEM / F12 supplemented with N2. the cells were photographed alive with phase contrast optics after 4 days in culture. The majority of the cells are of neuronal type, their neuritic processes connected to a cellular network. (a), (b) and (c) show cultures that were stained with anti-NFL, anti-MAP2 and anti-GFAP, respectively. In Figure 4, Es cells with a target insertion of ßqeo in the Sox2 gene were induced to differentiate by culture as aggregates ("embryoid bodies"). After 4 days they were exposed to 10 ~ 6 M retinoic acid for 4 additional days. The aggregates were then disassociated and the cells were plated on poly-D-lysine and laminin-coated plates in a serum free medium with N2 complement. The cultures were not selected or exposed to G418 either during the final 48 hours of the aggregate culture (b, f, h i) or for 24 hours after the placement in p l a ca s (d): a. The expression of ß-galactosidase bound to Sox2 in culture not selected 3 hours after plating. b. The expression of β-galactosidase bound to Sox2 in culture selected from G418 3 hours after plating. c. The expression of β-galactosidase bound to Sox2 in culture not selected 24 hours after plating. d. The expression of β-galactosidase bound to Sox2 in culture selected from G418 24 hours after plating. and. Immunostained with culture anti-Sox2 not selected 3 hours after plating. f. Immunostained with selected culture anti-Sox2 G418 3 hours after plating. g. Concerned with DAPI panel e. h. Concerned with DAPI panel f. i. Double labeling with anti-nestin (green) and anti-Sox2 (red / orange) of the crop ^ selected G418 3 hours later P 5 of the placement of plates. The graphic scale indicates 100 μm for (a, b, c, d), 66.7 μm for (e, f, g, h) and 50 μm for (i) • For Figure 5, cells expressing Sox2 klO were selected with G418 for 2 days in EB cultures, cells were disassociated and allowed to attach to culture plates for 3 hours before fixation. The expression for Pax3 (a), delta-1 (b), Mash-1 (c) and Math-4a (d) was detected by in situ hybridization with antidetection riboprobes; the presence of cells expressing Paxd was detected by staining the culture with an anti-Pax6 (e) antibody, the culture e double labeled with DAPI to locate the nuclei of all the cells (f). Graphic scale, 100 μm. For Figure 6, after an induction of 8 days of neural differentiation, cells were disassociated by trinitus, were plated at a density, and cultured in DMEM / F12 supplemented with N2 medium in the presence of 10 ng / ml of bFGF and ^ 200 μg / ml of G418. (a) overnight culture; (b) 4-day crop. Cell numbers increased approximately 10 times over the culture period. The cells expanded in the presence of bFGF maintained the expression of Sox2 as shown by X-gal dyeing. .10 Graphic scale: 50 μm. For Figure 7, cells expressing Sox2 selected by 48 hour exposure to G418 during embryoid body culture were plated and developed in the absence of G418 in N2 medium for 48 hours (a and b) or 96 hours (ce), or for 72 hours followed by an additional 72 hours in a Neurobasal medium plus B27 complement and 2% horse serum (fi) (Graphic scale, 20 100 μm): a, b. Double mmunoet tagging showing the sub-regulation of Sox-2 (a) in newly differentiated cells expressing the neuronal marker β-tubulma 3 (b). c. Immunostaining for neuronal marker ß3-tubulma with counter-staining of propidium iodide A showing a differentiation neuronal of > 90% of the cells. from. Double labeling for the smapsm-I (d) and MAP2 / Tau (e) neuronal markers. f. Immunostaining for GABA. .10 g. Phase contrast image of P field in f. h. Immunostaining for glutamate. i. Field phase contrast image in h. 15 In Figure 8, the embryoid bodies ES CCE-sox2 undergoing the selection of g418 were exposed to the indicated concentrations of recombinant sonic dredge protein. Cells were fixed and immunotined for the islet 1/2 motor neuron marker 48 hours after dissociation. In Figure 9, cells expressing sox-2 selected by exposure to g418 during body culture embody were disassociated, labeled with PKH26-GL (Sigma) and injected into the vesicles from the front of the brains of rat fetuses E16 i n u t er. Then the pregnancy was allowed to end. The young were sacrificed in P2. Vibratome sections were prepared and examined by fluorescence microscopy. The figure shows a cell labeled with representative PKH26-GL within the cortex exhibiting typical immature neuronal morphology. This study shows that the cells selected by Sox2 can be integrated and differentiated in the brain.

Materials and Methods Culture of ES cells The ES cell lines used in this study were: E14TG2a (Hooper et al., 1987), CGR8 (Mountford et al., 1994) and CCE-Sox2, a derivative of CCE (Bradley et al. ., 1984) in which a copy of the Sox2 gene has been disrupted by homologous recombination. All lines of ES cells were maintained in tissue culture plastic coated with gelatin in a Glasgow modified Eagle's medium (GMEM) supplemented with 10 ~ 4 2 -mercaptoethanol, serum of fetal bovine (FCS) aff? 10% and 100 U / ml of LIF (Smith, 1991).

Induction of differentiation. The basic protocol is based on the one described (Bain, 1995). The ES cells were started lightly in small masses and allowed to aggregate in suspension culture in the absence of LIF. After a 4 day culture, all the ransodic acid (RA) acid was added at a concentration of 10 ~ 6 M. After an additional 4 days, the aggregates were dissociated by incubation with trypsin and trituration. The cells were seeded at 3 * 10 5 cells / well in 4-well plates (Nunc) coated with poly i-D-lysine and laminin. The culture medium was DMEM / F12 (50/50) free of serum supplemented with N2 and, where specified, B27 (Gibco-BRL) plus 2% horse serum.

Preparation of the substrate. The tissue culture plates were pre-coated with poly-D-1 is ina (PDL-30-70 kDa, Sigma) for 20 minutes at a time. μg / ml concentration in PBS. The withdrawal PDL in excess and the plates were rinsed with PBS three times before coating with laminin (Sigma) at a concentration of 2-10 μg / ml in PBS overnight at 4 ° C.

Immunocytochemistry The dyeing for Soxl and Sox2 was carried out in fixed cultures in MEMFA (4% formaldehyde, 100 mM MOPS pH 7.4, 20 mM EGTA, lmM MgSO?) For 1 hour To stain the cells with antibodies against GABA and glutamate, cells were fixed with 1% glutaraldehyde in PBS (Turner, Neurochemist ry). For the detection of other intracellular antigens, the cultures were fixed in 4% para-formaldehyde in PB? during 15 minutes. The fixed cells were rinsed with PBS, incubated with blocking compensator (PBS, 1 mg / ml BSA, 0.1% Triton X-100, and 1% goat serum) for 30 minutes followed by incubation with primary antibodies in compensator Blocking overnight at 4 ° C The cells were then rinsed with PBS, and incubated with a specific species secondary antibody in blocking compensator for 1 hour. The cultures were rinsed with three changes of PBS, installed with a Vectashield installation medium (Vector) and examined under a fluorescent microscope. The double-label experiments were performed by simultaneously incubating cells in appropriate combinations of primary antibodies, followed by incubation with uncrossed reactive secondary antibodies. In some experiments, the cultures were contracted with propidium iodide or DAPI at concentrations of lng / ml and 5 μg / ml respectively. The following dilutions were used for the primary and secondary antibodies: anti-Soxl and rabbit anti- -Sox2 (1: 500), rabbit anti-GABA (1: 2000, Sigma), rabbit anti-glutamate (1: 4000, Sigma), mouse anti-β-tubulin 3 (1: 200, Sigma); mouse ant? -NF68 (1: 400, Sigma); rabbit anti? -MAP2, which reacts with MAP2 and Tau (1: 400, Sigma); anti-mouse GFAP (1: 400, Sigma), anti-i-sinapsm-I mouse (1:50, Chemicon), mouse anti-nestma (1:50, DSHB), mouse anti-Pax6 (1 : 10,). Goat anti-mouse IgG conjugated with Cy3 (1/50, Jackson ImmunoResearch), goat anti-mouse IgG conjugated with FITC (1: 100, Sigma), goat anti-rabbit Ig conjugated with FITC (1: 100, Sigma), goat anti-rabbit Ig 5 conjugated with TRITC (1:50, Sigma).

In situ hybridization of cultured cells. The protocol is based on that of (Rosen and Beddington, 1993) adapted for cells cultivated. Briefly, the cultures were fixed in 4% paraformaldehyde and permeated at -20 ° C in 100% methanol. The cells were then rehydrated through a series of methanol and finally placed in PBS with 0.1% Tween-15. The prehybridization was performed for 1-4 hours in hybridization compensator (50% ultra pure formamide, 5 * SSC, 4.5 pH, 50 mg / ml heparin, 100 μg / ml DNA and herring sperm tRNA, Tween-20 al 0.1%), the probes labeled with digoxigenin (DIG) were added at 1 μg / ml overnight at 70 ° C. The following day's rinses were performed three times during 30 minutes at 65 ° C in rinse aid (50% formaldehyde, 2 * SSC, 0.1% Tween-20), three rinses of 5 minutes in TBST (137 mM NaCl, 25 mM Tris-HCl, pH 7.6, 3 mM KCl, 0.1% Tween-20) and blocking 1 hour in serum / 10% TBST. The cells were then incubated overnight at 4 ° C with anti-DIG antibody coupled with alkaline phosphatase (1.2000, Boehringer-Mannheim). The next day the cells were rinsed three times 1 hour with TBST and three times for 10 minutes with alkaline phosphatase buffer (APB, 100 10 mM NaCl, 100 mM Tris pH 9.5, 50 mM I MgCl2, T een-20 at 0.1%). The alkaline phosphatase staining reaction was allowed to proceed for 3 hours until overnight with 4.5 μl / ml of NBT a BCIP of 3.5 μl / min in APB (Boehringer). 15 RNA probes labeled with DIG. The murine cDNAs used as templates for the riboprobes were a Pa193 fragment of 519 bp (provided by Dr. Rosa Beddington), a 700 bp Del t a-1 clone (provided by Dr. Domingos Henrique), a Mash-1 fragment of 670 bp and a Math-4A 1.5 kb cDNA (both were provided by Dr. Francois Guillemot). The DNAs are linearized and RNA synthesis was performed using T7, T3 or SP6 RNA polymerase, which includes a nucleotide mixture labeled with DIG as recommended by suppliers (Boehringer). The products were analyzed on a 0.8% agarose gel and approximately 1 μg / ml of the DIG-labeled anti-sense RNA was used for the hybridization of the cells.

Detection of β-galactosidase. Fixed cells were fixed (0.2% glutaraldehyde, 0.1 M pH 7.2 phosphate buffer, 2 mM MgCl2, 5 mM EGTA) for 10 minutes at 4 ° C and rinsed three times with rinse compensator ( 0.1 M pH 7.2 phosphate buffer, 2 mM MgCl2> The cells were then incubated at 37 ° C overnight with 1 mg / ml 5-bromo-4-chloro-3-indolyl-β-D -galactoside (X-gal), 4 mM potassium fericianide, 4 mM potassium ferrocyanide in rinse compensator (Baddington et al., 1989).

Results Effective generation of neurons and glia from ES cells The induction of neural differentiation was based on published methods (Bain, ^ 1995; Fraichard et al. , 1995) in which the ? 5 ES cells are added in suspension to form embryoid bodies, exposed to retic acid, and then they are reattached and grown on a substrate. Under these conditions the neuronal cells became evident in the excrescences after several days accompanied by a variety of other cell types. We introduced two variations in the protocol which encompassed the representation of neuronal cells. First, the embryoid bodies were disassociated before plating. This results in a homogeneous dispersion and immediately terminates the inductive and selective effects within the embryoid bodies.

Second, the cells were plated in a defined neuronal culture medium (DMEM / F12 plus N2) on substrates coated with poly-D-lysine and lammin which support the union and growth of neuronal cells. Each one of these procedures had an additive influence in the proportion of neural cells in the cultures. When combined, more than 50% of viable cells 4 days after plaque placement had extended process and where they were immu- noreactive for neuronal markers, light and heavy neurofusion chains, MAP2 / tau, or β-tubulin III ( Figure 1 and data not shown). A smaller proportion of cells, approximately 20%, expressed the astrocyte marker GFAP (not shown). Significantly, this observation is not specific to the cell line as comparable results were obtained with three independent ES cell lines and subsequent subclones. However, non-neural cell types remained in these cultures, often identifiable as large, non-refractory flat cells. If, at any point, DMEM / F12 plus N2 were supplemented with serum or mitogens (complement FGF-2 or B27), these non-neural cells expanded rapidly and progressively became the predominant cell type.

Detection of neural progenitors expressing The generation of a large proportion of erentiated neurons and glia suggested that the neural precursor cells may be detectable at a previous time point in the erentiation protocol. Figure 2a shows a representative culture 4 hours after plating. At this stage, the cells appear to be morphologically unerentiated. The soma of most cells is small, elongated or oval in shape. Some cells have short processes similar in length to their cell bodies. These morphological characteristics are similar to the previously reported primary neural precursors (Kalyaní et al. 1997). These cells do not express detectable NF-L or GFAP 3 hours after plaque placement. After overnight cultivation, less than 1% of the population was positive for either of these markers. Cultures were examined for the presence of the intermediate filament, nestina (Lendahl, et al., 1990), which is expressed in the neuroepi telial cells. Almost all cells were positive for nestin, however, because nestin expression ^ It is not strictly restricted to the neuroepithelium P 5 [Hockfield, 1985 # 868]. Therefore we look for a more specific marker. The transcription factor related to SRY Soxl is confined to the neuroepithelium of the neural plate and the dividing neural progenitors in the early mouse embryo (Pevny, unpublished data). The related Sox2 gene is expressed in an overlapping pattern that also covers the floor plate and early neural crest cells. The immunostaining of cells placed in plates freshly with antibodies raised against Soxl and Sox2 revealed that 40-50% of the cells were positive (Figure 2b and Figure 3e). These cells most likely correspond to the neural progenitors. 20 Selection and purification of neural progenitor cells expressing Sox-2. To isolate the pond of neural progenitors we use ES cells in which has integrated the selection marker bifunctional / gene relator ßqeo to the Sox2 gene by homologous recombination (ref). When it was induced to erentiate as described with Priority, approximately 50% of these 5 cells stained for β-galactosidase activity (Figure 2 and Table 1), consistent with the proportion of cells expressing the Sox2 protein. We apply G418 to erentiation cultures to eliminate non-cell negative neural to Sox2 (Figure 3). • G418 (200 μg / ml) was added after induction of retinoic acid, either during embryo body culture or after plaque placement. In both conditions it was evident the elimination of appreciable cells. However, crucially large numbers of cells survived by exhibiting a • Typical neuroepithe morphology. More than 90% of these cells gave staining of prominent β-20 galactosidase (Figure 4). The concordance with the Sox2 protein expression was confirmed by immunostaining (Figure 4, Table 1). The Soxl factor related to HMG-box, an exclusive marker of cells of the plur ipotential neural plate stage and CNS restricted precursors in the neural tube, was detectable in the vast majority of cells. Almost all viable cells expressed nestin.

The cells selected by Sox2 express neural progenitor specification markers. The organization in development and subdivision of the central nervous system is enhanced by temporal and spatial modeling of gene expression (Tanabe and Jessell, 1996). In order to measure the diversity of neural erentiation that might be achievable from ES cells in the absence of embryonic axial organization, we have begun to examine the expression of key determinants, Pax genes and neurogenic bHLH transcription factors. The paired transcription factors Pax3 and Pax6 are found in neural dividing precursors along the length of the embryonic neural tube. Pax3 is initially expressed in the neural plate and subsequently becomes undefined towards the dorsal half of the neural tube (Liem et al., 1995).

Pax6 is expressed predominantly in the ventral region of the neural tube (Walther and Gruss, 1991; ^ Tanabe and Jessell, 1996). The widespread expression of both pax genes was found in the cells selected for sox2 analyzed on the day of plaque placement (Figure 5 and Table 2). This suggests that neural precursors derived from ES cells can acquire both identities dorsals as ventral. I The bHLH, mashl and math4A (neurogenin) genes show a more restricted location for the subsets of the neural progenitors. The expression of each one was easily detected in cultures selected by sox2, but in insignificantly fewer cells than the pax gene products (Figure 5, Table 2). It is likely that the expression of mashl and math4A specify sub-populations of progenitors, since the distribution of these two transcription factors is mutually exclusive in most CNS regions (Gradwohl et al., 1996). Two markers were also examined precocious neuronal differentiation. The binder delta notch, which was found in compromised cells immediately before neuronal differentiation (ref), was expressed in only 1-2% of cells immediately after plaque placement, indicating that most cells are not found committed to terminal differentiation (See also Description). The expression of the LIMOD-1/2 homoodomain protein LIM, an early marker of the differentiation of motor neurons and ventral metaterurons (Ericson et al., 1992), was examined in cultures selected by Sox2 48 hours after placement in plates. In a reproducible way, 1-2% of the cells were immunoreacted at this stage (not shown), The cells selected by Sox2 proliferate in response to FGF-2. Several studies have presented evidence that the basic fibroblast growth factor (FGF-2) can support the proliferation of primary neural progenitors and immortalized progenitor cell lines (Palmer et al., 1997). The addition of FGF-2 (lOng / ml) to cultures selected by Sox-2 also stimulated cell proliferation. Figure 6 shows a culture stained with typical Xgal followed by the addition of FGF-2. Can • observe that all cells maintain a relatively undifferentiated morphology and show a strong Xgal stain. Such crops could be expanded and passed serially for at least two weeks. 10 Neural differentiation of cells selected by Sox2. In order to determine if the precursor cells selected by Sox2 maintained the capacity for neuronal differentiation, G418 was extracted from the medium. At 48 hours the cells began to extend neuritic processes and at 96 hours a network of neuron-type cells had formed (Figure 7). HE lost the activity of /? - galactos? Dasa of most cells (not shown) consistent with the sub-regulation of Sox2 in differentiation neurons (ref). The mmunothein confirmed the disappearance of the Sox2 protein (Figure 7b). The chains light and Heavy neurofilament of pan-neuronal markers (not shown), microtubule-associated proteins (MAPs / tau), / 3-tubulin III (Lee et al., 1990) and synapsin I were • 5 detectable from 48 hours on, coinciding with the sub-regulation of Sox2. At 96 hours, more than 90% of cells had large dendritic processes and expressed neuronal markers (Figure 7). Complementation of 10 culture medium with B27 and horse serum ! allowed the additional maturation of neuronal cells, evidenced both by the increased budding of dendrites and by the production of excitatory neurotransmitters and GABA inhibitors and glutamate (Figure 7). The mammalian nervous system is derived from neuroepithelial cells of the neural tube and its derived neural crest. During the neurogenesis, these progenitors proliferate neural, progressively lose their multipotentiality and finally differentiate into different types of post mitotic neurons and gual cells [Anderson, 1993 # 673, McKay, 1989 # 672 (Tanabe and Jessell, 1996; McKay, 1997)]. The mechanisms involved in the Determination and differentiation of neural precursor cells are the subject of intense research. However, this has been inhibited ^ so far because of relative inaccessibility and tissue complexity of the mammalian embryo.

A model system of the present invention in which neuroepithelial cells can be derived and undergo proliferation and differentiation provides a powerful tool to study factors I intrinsic and extrinsic that determine the specification and neural differentiation. ES cells have the ability to develop in any type of cell as is evidenced by its colonization of all lineages in chimeras (Beddington and Robertson, 1989). However, the prospect of using Es cells to dissect the development trajectories m vitro has been frustrated, by a inability to control or direct differentiation. In an embodiment of the invention described above, a strategy is provided for selecting precursors of the lineage of interest from embryoid bodies in development. Our Results show that viable neural precursors can be isolated by selection for Sox2 gene activity. These cells can be induced to proliferate or to differentiate into neurons. Therefore the survival and development of the neural lineage does not require continuous interaction with other cell types. In addition, discovering that cellular components can be excised Significant events without causing the disintegration of the embryoid bodies, or apparently disturbing the development of the surviving cells is both surprising and encouraging for the application of this approach to other lineages. In fact it is possible that such extirpation may favor the maintenance and expansion of specific germ cell populations by extracting the sources of induction differentiation from signals, which can be either cells derived from other lineages or more mature cells of the same lineage (Mountford and Smith, in personal communication). The heterogeneous expression of genes of determination (Figure 5) within the The cultures selected by Sox2 appear to be reflective of the specification of the progenitors within the neural tube. For the »Therefore, the requirements for induction, Growth and differentiation of individual progenitor types could be investigated, both by the addition of extracellular regulators to the culture system and by the genetic manipulation of ES cells before the differentiation. The last one is particularly relevant for situations in which the elimination of the homozygous gene or expression of transgen i n vi vo originate embryonic lethality. In addition, the ability to produce neurons genetically modified is prone to find significant applications in neuronal cell biology and biochemistry. It has been recently reported that the differentiated ES cells injected into the The brain of a developing rodent (Brustle et al., 1997) or even an adult (Deacon et al., 1998) can colonize the host nervous system and give rise to mature neuronal phenotypes. However, such transplants also contain non-neuronal cells. These foreign cells they can give rise to teratomas and other benign or malignant growths. They may also interfere with trophic signaling and guiding tracks of the host tissue to the injected neural cells. The prior isolation of the neural precursors according to the invention eliminates these problems. In addition, after the application of purified neural cells of lineage selection, you can access any stage of maturation and harvest and harvest for transplants. The invention opens the way for the development of human mult ipotential germ cells analogous to cells ES of a previously mentioned example for clinical use in transplants. Neurodegenerative conditions such as Parkinson's and Huntington's disease are potentially treatable by replacement strategies cellular and present compelling cases for the development of a renewable germ cell resource for the production of cells with the ability to be transplanted (Svendsen and Rosser, 1995; Rosenthal, 1998). He approach to lineage selection, in combination with 'appropriate instructive factors, is a valuable component of such a system, by allowing the generation of a defined cell population from a multipotent source.

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Table 1 Expression of neuroepithelial markers after the selection of G418 Markers -G 18 + G 18 for positive dyeing (average +/- SEM) /? - galactosidase 43.8 + 9.4 91 ± 2.6 Sox2 48.4 ± 1.1 95.5 + 1.1 Soxl 46.6 + 5.6 88.7 ± 5.1 Nestina * 90 ± 6.5 94 ± 3.2 G418 was applied to EB derived crops of the 6th day of induction in a concentration of 200 μg / ml. Two days later the aggregates were tripepped and the cell suspension was placed The substrate coated with poly-D-5 lysine / laminin in DMEM / F12 plus N2. The cultures were fixed 3 hours after plating by histochemical staining for? -galactosidase with X-gal or immunocytochemical staining for Soxl, Sox2 and ^ k 'nestin with specific antibodies. Positively stained cells scored under a 40x objective, seven to ten fields were counted for each example. The result is determined as a percentage average of two independent experiments.

(Nestin * is expressed in the somitic mesoderm as well as the neuroepithelium).

Claims (1)

1. CLAIMS Having described the invention as an antecedent, property is claimed as 1. Content of the following claims: 1. A method for generating a culture that is purified or enriched with respect to cells of a selected lineage, characterized in that it comprises: (i) introducing into a cell 10 mult ipotential a marker capable of being selected that is differentially expressed in cells of the selected lineage compared to its expression in 15 other cells, wherein the cells of the selected lineage constitute a subset of the cells obtainable from the mult ipot gingiva cell 1; 20 (ii) cultivate the mult ipotential cell i n vi vo to induce differentiation of the mult ipotential cell in a cell of the selected lineage or in a mixture 25 of cells that include the cells of the selected lineage or to induce the preferential survival, in a mixed culture of cells, of cells of the selected lineage; and (m) selecting the cells of the selected lineage according to the differential expression of the marker capable of being selected introduced in step (i) - 2. A method according to claim 1, characterized to generate a culture that is enriched or purified with respect to the progenitor cells of a selected lineage. A method according to claim 1 or 2, characterized in that the mult ippotential cell is selected from embryonic germ cells (ES), embryonic germ cells (EG), embryonic carcinoma cells (EC), a primary culture of fetal cells , a primary culture of postnatal cells, and a primary culture of adult cells 4. A method according to claim 1, 2 or 3, characterized in that it comprises genetically modifying mult ipotential cells to eliminate, mutate, substitute, or add genes in order to (i) test genetic functions in progenitor cells of the selected lineage, and / or (n) to make the selected cells most suitable for transplants. 5. A method according to any one of claims 1 to 4, characterized in that it comprises: (iv) introducing into the multi-ipotential cell a second marker capable of being selected that is expressed dif- ferrently in cells of a selected sub-sample compared to its expression in other cells, where the cells of the selected sub-mass are formed by the differentiation of cells from the selected progenitor lineage; and (v) when a culture of progemtor cells has been obtained from selected lineage, allow or induce differentiation of the cells and select the cells that express the second marker with ability to be selected. 6. A method according to any of claims 1 to 5, characterized in that the marker capable of being selected is introduced into the mult ipotential cell by objective integration or random integration of the gene trap in order to be operatively coupled to a gene that is expressed differentially. in progenitor cells of the selected lineage. A method according to any of claims 1 to 5, characterized in that the marker capable of being selected is introduced into the mult ipotential cell by means of random integration of a transgene in which the marker capable of being selected is operatively coupled to a gene that is expressed di fferentially in progenitor cells of the selected lineage. 8. A method according to any of claims 1 to 7, characterized in that the ipotential muí t cell is an ES, EG or EC and the method understand that it forms an embryoid body, or otherwise induce differentiation of cells. A method according to claim 8, characterized in that the differentiated cells are disassociated in order to form a culture of substantially individual cells, 10. A method according to claim 8 or 9, characterized in that the differentiated cells of an embryoid body are disassociated using a protease, such as trypsin. 11. A method according to any of claims 1 to 10, characterized to generate a culture that is purified or enriched with respect to neural progenitors, comprising introducing into the mult ipotential cell a selectable marker that is expressed differentially in Neural progenitor cells. 12. A method according to claim 11, characterized in that the marker capable of being selected is expressed in cells expressing a Sox gene. 13. A method according to the indication 12, characterized in that the Sox gene is selected from Sox 1, Sox 2 and Sox 3. 14. A method according to any of claims 1 to 10, for the generation of cardiac progenitor cells, characterized because the marker capable of being selected is expressed in the cells that express the gene Nkx 2.5 or GATA-4. 15. A method according to any of claims 1 to 10, characterized to generate a culture that is purified or enriched with respect to the hemat opoietic progenitors. 16. A method according to claim 15, characterized in that the marker capable of being selected is expressed in cells expressing CD34, CD44 or SCL. 17. A method according to any of claims 1 to 16, characterized 20 because the marker capable of being selected is a gene with antibiotic resistance and the method comprises culturing in the presence of antibiotic. 18. A method according to claim 25, to obtain a culture that is purified or it enriches with respect to the ventral progenitor cells, characterized in that the selectable marker is expressed di fferentially in the neural progenitor cells and the second marker capable of being selected is expressed dif ferrently in the ventral progenitor cells. 19. A method according to claim 10, characterized in that the second marker capable of being selected is expressed differentially in the cells expressing Pax 6. 20. An assay of the influence of a factor on a culture of progenitor cells of a selected lineage, characterized in that it comprises: A (i) introducing into a multipotential cell a marker with the ability to be selected that is expressed differentially in progenitor cells of the selected lineage compared to its expression in other cells, where the cells progenitors of Selected lineage constitute a sub-set of the cells obtainable from the mult ipotential cell, • (ii) cultivate the mu ti t ipot encial iin vi t ro to induce the differentiation of the mult ipot encial cell in a cell of the selected lineage or in a mixture of cells that includes cells of the selected lineage or to induce the preferential survival, in a mixed culture of cells, of cells of the selected lineage; and (iii) selecting those progenitor cells of the selected lineage according to the differential expression of the selectable marker introduced in step (i), and culturing the progenitor cells thus obtained from the selected lineage in the presence of the factor. 21. A method "according to claim 20, characterized according to any of claims 2 to 17. ^ 22. A method according to the claim 5 or 21 characterized to test if a factor has proliferating, maturing, toxic or protective influence on the progenitor cells of the selected lineage. 23. A method according to claim 10 characterized to test whether a factor has proliferative, maturational, cytotoxic or protective influence of glial in the neural progenitor cells. 24. A method for preparing a neural progenitor cell or a progeny differentiated therefrom for storage, characterized in that it comprises obtaining the cell in a method according to any of claims 1 to 17 and freezing the cell in the presence of a ciroprotector . 25. A method for generating purified neurons, characterized in that it comprises obtaining a purified culture with respect to the neural progenitors, using the method of 25 any of the rei indications 1 to 17, wherein the marker capable of being selected is expressed di fferentially in the cells expressing a Sox gene, and cultivating the progenitor k obtained in the presence of a medium 5 suitable for the differentiation of the progemtora in neurons. 26. A method according to the claim 25, characterized according to any of claims 2 to 17. A method according to claim 25 or 26, characterized to test if the factor has a proliferating, maturing, toxic or protective influence on the progenitor cells of the selected lineage. 28. A method according to the claim 27, characterized to test whether the factor has a proliferating, maturing, cytotoxic or protective influence of glial in the neural progenitor cells. 29. A neural progenitor cell, or a culture characterized in that it comprises a majority of neural progenitor cells, for transplants. 30. A cell or cells according to 25 claim 29, character Neural progenitor cells are neuronal cells. 31. A cell or cells according to Claim 29, characterized by the 5 neural progenitor cells are equal cells. 32. A method for preparing a neural progenitor cell or a differentiated progeny thereof for storage, characterized 10 because it comprises obtaining the cell in a method according to any of claims 1 to 17 and freezing the cell in the presence of a ciroprotector. 33. A method for generating purified neurons that comprises obtaining a purified culture with respect to the neural progenitors, which uses the method according to any of claims 1 to 17 characterized in that the marker capable of being The selected one is differentially expressed in the cells that express a Sox gene, and cultivate the obtained progenitors in the presence of a suitable medium for the differentiation of the progenitor in neurons. 34. 34. A neural progenitor cell for Transplants to treat neurodegenerative diseases or neuronal / brain damage. 35. A neural progenitor cell for transplants, obtainable from a cell selected from an ES cell, an EC cell, an EG cell, a primary culture of fetal cells, a primary culture of postnatal cells and a primary cell culture adult, characterized for transplants in order to treat neurodegenerative diseases or neuronal / brain damage. 36. A method of treating neurodegenerative diseases or neuronal / cerebral damage characterized in that it comprises the transplantation of a neuronal progenitor cell. 37. A method for amplifying a purified population of progenitor cells of a selected lineage, characterized in that it comprises maintaining the cells in culture in the presence of a mitogen; and a growth factor 38. A method according to claim 37, characterized in that the progenitor cells comprise a genetic coding for a marker capable of being selected, whose gene is differentially expressed in the progenitor cells compared to its expression in other cells, and because the method further comprises selecting the cells expressing the marker with ability to be selected. 39. A method according to the claim 38, characterized in that the method comprises maintaining the culture over a plurality of generations and periodically selecting the cells expressing the marker capable of being selected. 40. A method according to claim 38, characterized in that the method comprises maintaining the culture over a plurality of generations and continuously selecting the cells expressing the marker capable of being selected. 41. A method according to claim 40, characterized in that the marker capable of being selected is of antibiotic resistance and the method comprises the culture Continued in the presence of a tibiotic.