Classifications

• • C—CHEMISTRY; METALLURGY
  • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
  • C12N—MICROORGANISMS OR ENZYMES; COMPOSITIONS THEREOF; PROPAGATING, PRESERVING, OR MAINTAINING MICROORGANISMS; MUTATION OR GENETIC ENGINEERING; CULTURE MEDIA
  • 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
  • C12N5/0618—Cells of the nervous system
  • C12N5/0619—Neurons
• • C—CHEMISTRY; METALLURGY
  • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
  • C12N—MICROORGANISMS OR ENZYMES; COMPOSITIONS THEREOF; PROPAGATING, PRESERVING, OR MAINTAINING MICROORGANISMS; MUTATION OR GENETIC ENGINEERING; CULTURE MEDIA
  • 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
  • C12N5/0618—Cells of the nervous system
  • C12N5/0623—Stem cells
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K35/00—Medicinal preparations containing materials or reaction products thereof with undetermined constitution
  • A61K35/12—Materials from mammals; Compositions comprising non-specified tissues or cells; Compositions comprising non-embryonic stem cells; Genetically modified cells
• • C—CHEMISTRY; METALLURGY
  • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
  • C12N—MICROORGANISMS OR ENZYMES; COMPOSITIONS THEREOF; PROPAGATING, PRESERVING, OR MAINTAINING MICROORGANISMS; MUTATION OR GENETIC ENGINEERING; CULTURE MEDIA
  • C12N2500/00—Specific components of cell culture medium
  • C12N2500/02—Atmosphere, e.g. low oxygen conditions
• • C—CHEMISTRY; METALLURGY
  • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
  • C12N—MICROORGANISMS OR ENZYMES; COMPOSITIONS THEREOF; PROPAGATING, PRESERVING, OR MAINTAINING MICROORGANISMS; MUTATION OR GENETIC ENGINEERING; CULTURE MEDIA
  • C12N2500/00—Specific components of cell culture medium
  • C12N2500/90—Serum-free medium, which may still contain naturally-sourced components
• • C—CHEMISTRY; METALLURGY
  • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
  • C12N—MICROORGANISMS OR ENZYMES; COMPOSITIONS THEREOF; PROPAGATING, PRESERVING, OR MAINTAINING MICROORGANISMS; MUTATION OR GENETIC ENGINEERING; CULTURE MEDIA
  • C12N2501/00—Active agents used in cell culture processes, e.g. differentation
  • C12N2501/10—Growth factors
  • C12N2501/14—Erythropoietin [EPO]

Definitions

• This invention relates to methods of influencing multipotent neural stem cells to produce progeny that differentiate into neurons by exposing the stem cells and their progeny to erythropoietin.
• stem cells The role of stem cells in the adult is to replace cells that are lost by natural cell death, injury or disease.
• the low turnover of cells in the mammalian CNS together with the inability of the adult mammalian CNS to generate new neuronal cells in response to the loss of cells following injury or disease had led to the assumption that the adult mammalian CNS does not contain multipotent neural stem cells.
• the critical identifying feature of a stem cell is its ability to exhibit self- renewal or to generate more of itself.
• the simplest definition of a stem cell would be a cell with the capacity for self-maintenance.
• a more stringent (but still simplistic) definition of a stem cell is provided by Potten and Loeffler (Development, 110: 1001, 1990) who have defined stem cells as "undifferentiated cells capable of a) proliferation, b) self-maintenance, c) the production of a large number of differentiated functional progeny, d) regenerating the tissue after injury, and e) a flexibility in the use of these options.”
• CNS disorders encompass numerous afflictions such as neurodegenerative diseases (e.g. Alzheimer's and Parkinson's), acute brain injury (e.g. stroke, head injury, cerebral palsy) and a large number of CNS dysfunctions (e.g. depression, epilepsy, and schizophrenia).
• Degeneration in a brain region known as the basal ganglia can lead to diseases with various cognitive and motor symptoms, depending on the exact location.
• the basal ganglia consists of many separate regions, including the striatum (which consists of the caudate and putamen), the globus pallidus, the substantia nigra, substantia innominate, ventral pallidum, nucleus basalis of Meynert, ventral tegmental area and the subthalamic nucleus.
• Many motor deficits are a result of neuronal degeneration in the basal ganglia.
• Huntington's Chorea is associated with the degeneration of neurons in the striatum, which leads to involuntary jerking movements in the host.
• Degeneration of a small region called the subthalamic nucleus is associated with violent flinging movements of the extremities in a condition called ballismus, while degeneration in the putamen and globus pallidus is associated with a condition of slow writhing movements or athetosis.
• Other forms of neurological impairment can occur as a result of neural degeneration, such as cerebral palsy, or as a result of CNS trauma, such as stroke and epilepsy.
• Alzheimer's Disease In recent years neurodegenerative disease has become an important concern due to the expanding elderly population which is at greatest risk for these disorders. These diseases, which include Alzheimer's Disease and Parkinson's Disease, have been linked to the degeneration of neuronal cells in particular locations of the CNS, leading to the inability of these cells or the brain region to carry out their intended function. In the case of Alzheimer's Disease, there is a profound cellular degeneration of the forebrain and cerebral cortex. In addition, upon closer inspection, a localized degeneration in an area of the basal ganglia, the nucleus basalis of Meynert, appears to be selectively degenerated. This nucleus normally sends cholinergic projections to the cerebral cortex which are thought to participate in cognitive functions including memory.
• Parkinson's Disease degeneration is seen in another area of the basal ganglia, the substantia nigra par compacta. This area normally sends dopaminergic connections to the dorsal striatum which are important in regulating movement. Therapy for Parkinson's Disease has centered upon restoring dopaminergic activity to this circuit through the use of drugs.
• neural grafts may avert the need not only for constant drug administration, but also for complicated drug delivery systems which arise due to the blood-brain barrier.
• neural grafts may avert the need not only for constant drug administration, but also for complicated drug delivery systems which arise due to the blood-brain barrier.
• cells used for transplantation which carry cell surface molecules of a differentiated cell from another host can induce an immune reaction in the host.
• the cells must be at a stage of development where they are able to form normal neural connections with neighboring cells. For these reasons, initial studies on neurotransplantation centered on the use of fetal cells. Several studies have shown improvements in patients with Parkinson's Disease after receiving implants of fetal CNS tissue.
• Implants of embryonic mesencephalic tissue containing dopamine cells into the caudate and putamen of human patients was shown by Freed et al. (N Engl J Med 327:1549- 1555 (1992)) to offer long-term clinical benefit to some patients with advanced Parkinson's Disease. Similar success was shown by Spencer et al. (N Engl J Med 327: 1541-1548 (1992)). Widner et al. (N Engl J Med 327: 1556-1563 (1992)) have shown long-term functional improvements in patients with MPTP-induced Parkinsonism that received bilateral implantation of fetal mesencephalic tissue. Perlow, et al.
• the tissue may already be infected with a bacteria or virus, thus requiring expensive diagnostic testing for each fetus used.
• diagnostic testing might not uncover all infected tissue.
• the diagnosis of HIV-free tissue is not guaranteed because antibodies to the virus are generally not present until several weeks after infection.
• a method of producing neurons or neuronal progenitor cells which can be used for transplantation or other purposes comprises inducing multipotent neural stem cells to produce neuronal progenitor cells by proliferating the multipotent neural stem cells in the presence of growth factors and erythropoietin.
• the erythropoietin may originate from the population of neural cells by subjecting the cells to hypoxic insult which induces neural cells to express erythropoietin.
• the erythropoietin may be provided exogenously.
• multipotent or oligopotent neural stem cell refers to an undifferentiated cell which is capable of self-maintenance.
• a stem cell is capable of dividing without limit.
• the non-stem cell progeny of a multipotent neural stem cell are termed "progenitor cells.”
• progenitor cells A distinguishing feature of a progenitor cell is that, unlike a stem cell, it has limited proliferative ability and thus does not exhibit self-maintenance. It is committed to a particular path of differentiation and will, under appropriate conditions, eventually differentiate.
• a neuronal progenitor cell is capable of a limited number of cell divisions before giving rise to differentiated neurons.
• a glial progenitor cell likewise is capable of a limited number of cell divisions before giving rise to astrocytes or oligodendrocytes.
• a neural stem cell is multipotent because its progeny include both neuronal and glial progenitor cells and thus is capable of giving rise to neurons, astrocytes, and oligodendrocytes .
• EPO erythropoietin
• Multipotent neural stem cells can be obtained from embryonic, juvenile, or adult mammalian neural tissue (e.g. mouse and other rodents, and humans and other primates) and can be induced to proliferate in vitro or in vivo using the methods disclosed in published PCT application WO 93/01275 and U.S. Pat. No. 5,750,376. Briefly, the administration of one or more growth factors can be used to induce the proliferation of multipotent neural stem cells.
• Preferred proliferation-inducing growth factors include epidermal growth factor (EGF), amphiregulin, acidic fibroblast growth factor (aFGF or FGF-1), basic fibroblast growth factor (bFGF or FGF-2), transforming growth factor alpha (TGF ⁇ ), and combinations thereof.
• neural tissue is dissociated and the primary cell cultures are cultured in a suitable culture medium, such as the serum-free defined medium described in Example 1.
• a suitable proliferation- inducing growth factor such as EGF (20 ng/ml) is added to the culture medium to induce multipotent neural stem cell proliferation.
• neurospheres Clusters of undifferentiated neural cells termed "neurospheres", which after several days in culture, lift off the floor of the culture dish and float in suspension.
• Each neurosphere results from the proliferation of a single multipotent neural stem cell and is comprised of daughter multipotent neural stem cells and neural progenitor cells.
• the neurospheres can be dissociated to form a suspension of undifferentiated neural cells and transferred to fresh growth-factor containing medium. This reinitiates proliferation of the stem cells and the formation of new neurospheres. In this manner, an unlimited number of undifferentiated neural stem cell progeny can be produced by the continuous culturing and passaging of the cells in suitable culture conditions.
• WO 94/10292 and U.S. Pat. No. 5,750,376 which can be used to induce the proliferated neural stem cell progeny to differentiate into neurons, astrocytes and oligodendrocytes.
• the proliferating stem cells can be exposed to EPO.
• the EPO can be exogenously added at concentrations from about 0.1 to 10 units/ml.
• the neural cells can be induced to express endogenous EPO by subjecting the cells to hypoxic insult.
• Subsequent differentiation of the progenitor cell progeny results in at least a two-fold increase in the numbers of neurons generated compared to progeny of stem cells that have not been exposed to EPO, as evidenced by irnmunocytochemical analysis.
• Differentiation of cells that have not been exposed to endogenously added EPO or hypoxic insult typically results in a population of cells containing about 3 % neurons. The percentage of neurons increases to about 6% with hypoxia treatment, and to about 10% with exposure to exogenous EPO, with the percentage of astrocytes and oligodendrocytes remaining about the same as the control populations.
• Washout experiments in which the growth factor/EPO medium is removed after 24 hours and changed to regular growth factor-containing medium, reveals that the EPO instructs the stem cells prior to their first cell division, to produce more neurons.
• the continued presence of EPO after the initial 24 hours does not result in a further increase in the numbers of neurons over cultures subjected to EPO for a 24 hour period.
• Neuronal progenitor cells or neurons or a combination thereof can be harvested and transplanted into a patient needing neuronal augmentation.
• Neuronal progenitor cells are particularly suitable for transplantation because they are still undifferentiated and, unlike differentiated neurons, there are no branched processes which can be damaged during transplantation procedures. Once transplanted, the neuronal progenitor cells differentiate in situ into new, functioning neurons. Suitable transplantation methods are known in the art and are disclosed in U.S. Pat. No. 5,750,376.
• a patient's endogenous multipotent neural stem cells could be induced to proliferate in situ to produce neuronal progenitor cells by administering to the patient a composition comprising one or more growth factors which induces the patient's neural stem cells to proliferate and EPO which instructs the proliferating neural stem cells to produce neuronal progenitor cells which eventually differentiate into neurons.
• a composition comprising one or more growth factors which induces the patient's neural stem cells to proliferate and EPO which instructs the proliferating neural stem cells to produce neuronal progenitor cells which eventually differentiate into neurons.
• Suitable methods for administering a composition to a patient which induces the in situ proliferation of the patient's stem cells are disclosed in U.S. Pat. No. 5,750,376.
• Tissue was mechanically dissociated into serum-free medium composed of a 1: 1 mixture of Dulbecco's modified Eagle's medium (DMEM) and F-12 nutrient
• DMEM Dulbecco's modified Eagle's medium
• a defined hormone mix and salt mixture (Sigma) that included insulin (25 ⁇ g/ml), transferrin (100 ⁇ g/ml), progesterone (20 nM), putrescine (60 ⁇ M), and selenium chloride (30 nM) was used in place of serum.
• the complete medium was supplemented with 20 ng/ml of EGF (Collaborative Research).
• EGF Collaborative Research
• Cells were seeded in a T25 culture flask and housed in an incubator at 37°C, 100% humidity, 95% air/5% CO 2 . Stem cells within the cultures began to proliferate within 3-4 days and due to a lack of substrate lifted off the floor of the flask and continued to proliferate in suspension forming neurospheres.
• EXAMPLE 2 Hypoxia-induced neurogenesis After 6 days in vitro primary neurospheres formed using the methods described in Example 1 were dissociated and were replated in EGF-containing medium. After 24 hours, the cells were exposed to a modest hypoxic insult by decreasing the concentration of oxygen in the culture medium for varying lengths of time (from 1 to 12 hours) from normal levels of 135 mmHg to 30-40 mmHg. The cells were then cultured in the EGF-containing complete medium described in Example 1 in 95 % air/5% CO 2 for 7 days. Hypoxia did not prevent multipotent neural stem cell proliferation, as evidenced by the formation of secondary neurospheres. The number of progeny produced from hypoxia-treated stem cells was the same as that in control cultures not subjected to hypoxic insult.
• Secondary neurospheres generated from untreated or hypoxia-treated stem cells were dissociated into single cells and induced to differentiate by plating between 0.5 x 10 6 and 1.0 x 10 6 cells onto poly-L-ornithine-coated (15 ⁇ g/ml) glass coverslips in 24 well Nuclon (1.0 ml/ well) culture dishes in EGF-free complete medium optionally supplemented with 1 % FBS. After 7 days, the cells were assayed using immunocytochemical analysis for the presence of neurons. Cultures that had been subjected to hypoxic conditions for 1 to 4 hours had approximately a two-fold increase in the percentage of neurons (approx. 6%) over control cultures (approx. 3 %).
• hypoxia-induced factor HIP is a transcription factor for EPO.
• the 4-hour hypoxia-induced increase in neurogenesis could be blocked by the addition of an EPO-neutralizing antibody at 3 ⁇ g/ml.
• Example 2 After 6 days in vitro primary neurospheres formed using the methods described in Example 1 were dissociated and replated in complete medium containing EGF at 20 ng/ml and human recombinant EPO at 0.1 to 10 units/ml for either 24 hours or 7 days under normal oxygen conditions (95% air/5% CO 2 ; 135 mmHg). In both cases, immunocytochemistry revealed an EPO dose-dependent three-fold increase in the numbers of neurons generated.

Landscapes

• Health & Medical Sciences (AREA)
• Engineering & Computer Science (AREA)
• Biomedical Technology (AREA)
• Life Sciences & Earth Sciences (AREA)
• Wood Science & Technology (AREA)
• Organic Chemistry (AREA)
• Chemical & Material Sciences (AREA)
• Biotechnology (AREA)
• Zoology (AREA)
• Bioinformatics & Cheminformatics (AREA)
• Genetics & Genomics (AREA)
• Neurology (AREA)
• Microbiology (AREA)
• Cell Biology (AREA)
• Neurosurgery (AREA)
• Biochemistry (AREA)
• General Engineering & Computer Science (AREA)
• General Health & Medical Sciences (AREA)
• Developmental Biology & Embryology (AREA)
• Micro-Organisms Or Cultivation Processes Thereof (AREA)
• Medicines Containing Material From Animals Or Micro-Organisms (AREA)
• Medicines That Contain Protein Lipid Enzymes And Other Medicines (AREA)
• Peptides Or Proteins (AREA)

Priority Applications (3)

Applications Claiming Priority (2)

Publications (1)

Family

ID=22046528

Family Applications (1)

Country Status (5)

Cited By (19)

Families Citing this family (47)

Citations (4)

Family Cites Families (3)

• 1998
  • 1998-10-20 US US09/175,890 patent/US6165783A/en not_active Expired - Lifetime
  • 1998-10-23 JP JP2000518058A patent/JP2001520878A/ja active Pending
  • 1998-10-23 CA CA2307017A patent/CA2307017C/en not_active Expired - Fee Related
  • 1998-10-23 AU AU96173/98A patent/AU9617398A/en not_active Abandoned
  • 1998-10-23 WO PCT/CA1998/000991 patent/WO1999021966A1/en not_active Ceased
• 2000
  • 2000-12-20 US US09/742,484 patent/US6368854B2/en not_active Expired - Fee Related
• 2002
  • 2002-02-21 US US10/080,161 patent/US20020094571A1/en not_active Abandoned
  • 2002-03-12 US US10/095,727 patent/US20020098585A1/en not_active Abandoned
  • 2002-12-31 US US10/335,477 patent/US20030104619A1/en not_active Abandoned
• 2004
  • 2004-08-31 US US10/930,115 patent/US6924142B2/en not_active Expired - Fee Related
• 2005
  • 2005-06-23 US US11/165,546 patent/US20060127372A1/en not_active Abandoned

Patent Citations (4)

Non-Patent Citations (10)

Also Published As

Similar Documents

Legal Events