Methods for reprogramming cells and uses thereof

1. A method of obtaining a neural multipotent or unipotent cell, comprising:

i) providing a cell of a first type which is not a neural multipotent or unipotent cell;

ii) increasing expression of at least one neural multipotent or unipotent gene regulator in the cell of a first type, to a level at which the at least one neural multipotent or unipotent gene regulator is capable of driving transformation of the cell of a first type into the neural multipotent or unipotent cell, wherein the at least one multipotent or unipotent gene regulator is Musashi1 (Msi1), Neurogenin 2 (Ngn2), or both Msi1 and Ngn2; and

iii) placing or maintaining the cell in a neural cell culture medium and maintaining sufficient intracellular levels of the at least one multipotent or unipotent gene regulator for a sufficient period of time to allow a stable neural multipotent or unipotent cell to be obtained.

2. The method of claim 1 , wherein the neural multipotent or unipotent cell is characterized by a stable repression of a plurality of genes expressed in the cell of a first type.

3. The method of claim 1 , wherein the sufficient period of time allows stable endogenous expression of the neural multipotent or unipotent gene regulator in step (iii) and allows a stable expression of a plurality of genes whose stable expression is characteristic of the phenotypical and/or functional properties of the neural multipotent or unipotent cell, where stable expression of one or more of the plurality of genes is not characteristic of phenotypical and functional properties of an embryonic stem cell, in order to transform the cell of a first type into the neural multipotent or unipotent cell.

4. The method of claim 1 , wherein the cell of a first type is transfected with at least one expression vector encoding polypeptide(s) selected from the group consisting of Musashi1 (Msi1), Neurogenin 2 (Ngn2), and Msi1 and Ngn2.

5. The method of claim 1 , wherein the neural multipotent or unipotent cell so obtained possesses one or more of the following characteristics:

i) expression of one or more neural lineage cell marker selected from the group consisting of Sox2, Nestin, Glial Fibrillary acidic protein (GFAP), βIII-tubulin, Msi1 and Ngn2;

ii) form neurospheres in a neurosphere colony formation assay;

iii) is capable of differentiation into at least one cell expressing a marker specific for a neuronal, astrocyte or oligodendrocyte cell;

iv) has one or more morphological neurite processes selected from the group consisting of axons and dendrites, wherein the neurite processes are greater than one cell diameter in length upon neuronal differentiation;

v) expression of at least one neural-specific antigen selected from the group consisting of neural-specific microtubule associated protein 2 (Map2), neural cell adhesion molecule (NCAM), and a marker for a neurotransmitter upon neuronal differentiation;

vi) expression of one or more functional neural markers upon neuronal differentiation;

vii) capable of releasing one or more neurotrophic factors;

viii) capable of significantly improving one or more neurological functional measures after placement of an adequate number of the said neural multipotent or unipotent cells into the void in a brain ablation model;

ix) capable of significantly improving or maintaining one or more neurological functional measures after injecting an adequate number of the said neural multipotent or unipotent cells into an Experimental Allergic Encephalomyelitis (EAE) mouse model; and

x) capable of improving one or more neurological functional measures more significantly than human fetal neuroprogenitor cells (hNPCs) in central nervous system injury or neurodegenerative models.

6. The method of claim 1 , wherein the neural multipotent cell so obtained possesses all of the following characteristics:

(i) expresses neural multipotent markers including Nestin and Sox2;

(ii) can self-renew for significantly longer than a somatic cell;

(iii) is not a cancerous cell;

(iv) is stable and not artificially maintained by forced gene expression and may be maintained in standard neural stem cell media;

(v) can differentiate to a neuroprogenitor cell, a neural precursor cell, a neuron, an astrocyte, an oligodendrocyte or to another more differentiated cell type of the neural lineage; and

(vi) does not exhibit uncontrolled growth, teratoma formation, and tumor formation in vivo.

7. The method of claim 1 , wherein a plurality of neural multipotent or unipotent cells are obtained and wherein the plurality of neural multipotent or unipotent cells are organized within a three-dimensional structure.

8. The method of claim 1 , wherein the cell of the first type is selected from the group consisting of adipose-derived stem cell, mesenchymal stem cell, hematopoietic stem cell, skin derived precursor cell, hair follicle cell, fibroblast, keratinocyte, epidermal cell, endothelial cell, epithelial cell, granulosa epithelial cell, melanocyte, adipocyte, chondrocyte, hepatocyte, B lymphocyte, T lymphocyte, granulocyte, macrophage, monocyte, mononuclear cell, pancreatic islet cell, sertoli cell, neuron, glial cell, cardiac muscle cell, and other muscle cell.

9. The method of claim 1 , wherein the cell of the first cell type is a human fibroblast cell, human keratinocyte, human adipose derived stem cell, human mesenchymal stem cell, or human hematopoietic stem cell.

10. The method of claim 1 , comprising treating the cell of a first cell type with a cytoskeleton disruptor.

11. The method of claim 10 , wherein the cytoskeleton disruptor is Cytochalasin B or a myosin inhibitor.

12. The method of claim 1 , wherein the neural unipotent cell so obtained possesses all of the following characteristics:

(i) expresses a neuronal marker and/or a glial marker;

(ii) is not a cancerous cell;

(iii) is stable and not artificially maintained by forced gene expression and may be maintained in standard neural or glial cell media; and

(iv) does not exhibit uncontrolled growth, teratoma formation, and tumor formation in vivo.

13. The method of claim 12 , wherein the neuronal marker is βIII-tubulin.

14. The method of claim 12 , wherein the glial marker is selected from the group consisting of GFAP and O4.

15. The method of claim 1 , wherein the stable neural multipotent or unipotent cell obtained is a multipotent cell and is capable of differentiating into a neural unipotent or somatic cell.

16. The method of claim 1 , wherein the stable neural multipotent or unipotent cell obtained is a unipotent cell and is capable of differentiating into a neural somatic cell.

17. The method of claim 1 , wherein the stable neural multipotent or unipotent cell obtained is capable of differentiating into a neuroprogenitor cell, a neural precursor cell, a neuron, an astrocyte, an oligodendrocyte or to another more differentiated cell type of the neural lineage.

18. A method of obtaining a neural multipotent, unipotent or somatic cell, comprising:

i) providing a cell of a first type which is not a neural multipotent, unipotent or somatic cell;

ii) transiently increasing expression of at least one neural multipotent or unipotent gene regulator in the cell of a first type, to a level at which the at least one neural multipotent or unipotent gene regulator is capable of driving transformation of the cell of a first type into the neural multipotent, unipotent or somatic cell, wherein the at least one multipotent or unipotent gene regulator is Musashi1 (Msi1), Neurogenin 2 (Ngn2), or both Msi1 and Ngn2; and

iii) placing or maintaining the cell in a neural cell culture medium and maintaining sufficient intracellular levels of the at least one multipotent or unipotent gene regulator for a sufficient period of time to allow a stable neural multipotent, unipotent or somatic cell to be obtained.

19. The method of claim 18 , wherein the neural multipotent cell so obtained possesses all of the following characteristics:

(i) expresses neural multipotent markers including Nestin and Sox2;

(ii) can self-renew for significantly longer than a somatic cell;

(iii) is not a cancerous cell;

(iv) is stable and not artificially maintained by forced gene expression and may be maintained in standard neural stem cell media;

(v) can differentiate to a neuroprogenitor cell, a neural precursor cell, a neuron, an astrocyte, an oligodendrocyte or to another more differentiated cell type of the neural lineage; and

(vi) does not exhibit uncontrolled growth, teratoma formation, and tumor formation in vivo.

20. The method of claim 18 , wherein the neural unipotent cell so obtained possesses all of the following characteristics:

(i) expresses a neuronal marker and/or a glial marker;

(ii) is not a cancerous cell;

(iii) is stable and not artificially maintained by forced gene expression and may be maintained in standard neural or glial cell media; and

(iv) does not exhibit uncontrolled growth, teratoma formation, and tumor formation in vivo.