Methods of derivation of neuronal progenitor cells from embryonic stem cells

1. A method of producing a population of neuronal progenitor cells, comprising:

a) culturing embryonic stem cells, sourced from totipotent cells, in a growth medium comprising basic fibroblast growth factor (b(FGF) or fibroblast growth factor 2 (FGF2) and retinoic acid for a period of about 1-7 days, wherein the growth medium is without animal serum and without bone morphogenic proteins BMP4 and BMP7;

b) culturing the cell population of step a) in suspension (non-adherent conditions) in a growth medium for an additional period of about 5-10 days wherein the growth medium comprises basic fibroblast growth factor (bFGF) or fibroblast growth factor 2 (FGF2), to form aggregates comprising isolated neuronal progenitor cells, wherein the growth medium is without animal serum and without bone morphogenic proteins BMP4 and BMP and wherein the medium is changed one or more times every 12 to 72 hours or provided by a continuous flow system, thereby producing a cell population in which at least 75% of the cells are neuronal progenitor cells; and

c) identifying cells within the population that express pax6 and nestin, and NeuN and Tuj1,

wherein at least 90% of the population of human neural progenitor cells express Pax6 and nestin and also express at least one of NeuN and Tuj1.

2. The method of claim 1 , wherein at least about 90% of the cell population are neuronal progenitor cells.

3. The method of claim 1 , wherein at least about 95% of the cell population are committed to neuronal progenitor cells.

4. The method of claim 1 , wherein following culturing the cell population of step a) in an adherent substrate for about 1-7 days, the cells are enzymatic dissociated from the substrate prior to culturing the cell population in a non-adherent condition or suspension.

5. The method of claim 1 , wherein the aggregates comprise about 25-500 neuronal progenitor cells.

6. The method of claim 1 , further comprising step d), removing non-aggregating cells.

7. The method of claim 1 , further comprising following steps a) or b), isolating or purifying the cells which are committed to neuronal progenitor cells.

8. The method of claim 1 , further comprising step d), isolating or purifying the neuronal progenitor cells.

9. The method of claim 1 , further comprising step d), proliferating the neuronal progenitor cells in a growth medium comprising a suspension culture, thereby increasing numbers of neuronal progenitor cells.

10. The method of claim 1 , further comprising step d), isolating one or more of said neuronal progenitor cells and transferring the one or more cells into a growth medium comprising suspension culture.

11. The method of claim 1 , wherein there are less than about 10% in aggregate of astrocytes, oligodendrocytes, fibroblasts, or glial cells in the culture.

12. The method of claim 1 , wherein there are less than about 10% in aggregate of cells that do not express both a developmental marker and a neuron marker in the culture.

13. The method of claim 1 , wherein at least 75% of said cell population stably or transiently express at least one of the developmental markers and one neuron marker, the developmental marker selected from the group consiting of: HNF-3β, Pax3, PAx6, Shh, Lhx3, Chx10, Pax7, H4C4, VIN-IS-53, AC4, FP3, NOT1, Wnt1, and IsIand nestin and the neuron marker selected from the group consisting of MAP2 (microtubule associate protein), NF200 (neuro-filament 200), Tuj 1 (neuron specific beta tubulin) and NeuN (Neuronal nuclei).

14. The method of claim 1 , wherein at least a proportion of said cells exhibit one or more of the following characteristics: a small oval or triangular cell shape with minimal cytoplasm; unipolar or bipolar with short expansions/processes optionally with a spliced termination; active cell division on the longitudinal axis; a polarized orientation; limited migratory ability; or form a multi-cell layered structure on an adherent substrate or a cell agglomerate in suspension.