B4: Diseases of the nervous system. Embryonic and induced pluripotent stem cells: A new tool to model diseases of the nervous system

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1 B4: Diseases of the nervous system Embryonic and induced pluripotent stem cells: A new tool to model diseases of the nervous system Y.-A. Barde May

2 Key Properties of Stem Cells Self-renew indefinitely Progeny generates different cell types

3 2 Different Types of Stem Cells Embryonic Stem Cells Tissue Stem Cells Both self-renew indefinitely and it is their differentiation potential that distinguishes them

4 Stem cells and diseases of the nervous system Tissue stem cells would be better suited for cellular therapy (c.f. hematopoietic system) Embryonic or induced pluripotent cells are a great resource for disease modeling

5 Tissue stem cells Hematopoeitic system Nervous system

6 Key findings Discovery of somatic stem cells: Till and McCulloch (1961) Isolation of mouse HSC (1988) One defined cell can reconstitute the hematopoietic system and generate more than10 9 cells per day Also generates a stable pool of HSCs ( )

7 Hierarchy HSC: slow and rare division, resides in niches, does not senesce, can home when injected MPPs: Multipotent progenitors (first distinct progeny of HSCs) 2 oligopotent progenitors: CLP (common lymphoid progenitor) and CMP (common myeloid progenitor)

8 Stem cells and tumor cells Tumor cells are also characterized by high telomerase activity May readily arise from dysregulated progenitors: mutations including translocations, lack of cell death, escape immune surveillance

9 Nervous system Cell division noted in adult bird, rodent and cat brains in the 1960 s Neurons in the olfactory bulb are constantly renewed in rodents Songbirds

10 The SVZ generates new neurons in the adult brain Alvarez-Buylla and Garcia-Verdugo (2002) J. Neurosci. 22, 630

11 Organization and lineage in the SVZ Alvarez-Buylla and Garcia-Verdugo (2002) J. Neurosci. 22, 632

12 New neurons are also incorporated in the adult dentate gyrus Taupin and Gage (2002) J. Neurosci. Res. 69, 746

13 Stem cells in the adult brain are regionally specified Merkle et al. (2007) Science 317,

14 Stem cell-derived neuronal phenotypes in the OB

15 Cells labeled at birth preserved their regional identity

16 Cultured cells remember where they come from

17 Alternative to stem cell transplantation Activation of endogenous neurogenesis

18 Pluripotency of cultured ES cells An unstable state captured in vitro thanks to LIF The transcription factors Oct-4, Sox2 and nanog play critical roles This role is now better understood: Blocking FGF signaling and GSK activity makes LIF and serum redundant (Ying et al. 2008, Nature 453, ) Isolation of RAT stem cells finally possible (see Buehr et al. and Li et al. Cell 2008, 135, )

19 Key to homogeneity: Maintaining pluripotency of all cells Silva and Smith (2008) Cell 132,

20 Why use cultured embryonic stem cells to study the nervous system? Unbiased phenotypic and molecular analyses with wild-type and genetically engineered cells Prerequisite: Homogenous cell populations

21 ES cells can generate pure populations of defined neuronal progenitors +RA ES cells: selection for most rapidly dividing, i.e. undifferentiated ES cells Progenitors Pax6+ Radial Glial Cells Neurons > 90% Glutamatergic neurons Bibel et al. Nature Neuroscience (2004) 7, Bibel et al. Nature Protocols (2007) 2,

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24 ES cells-derived neurons form functinal synaptic contacts

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26 Neurotrophin signalling: 2 different receptors

27 Controlled overexpression of p75 NTR in ES cells tau egfp/egfp (control) tau egfp/rp75 (tau::p75 NTR )

28 tau gfp/rp75 (tau::p75) tau promoter GFP rat p75 tau gfp/gfp (G30) tau promoter GFP GFP

29 tau::p75 NTR neurons at d3 (βiii tubulin staining)

30 WT cells labeled Cy5 (red) 200 kda ph kda Hans Vosshol, Dieter Müller and Sjouke Hoving (Novartis)

31 p75 NTR ::tau cells labeled Cy3 (green) 200 kda ph kda

32 Overlay 200 kda ph kda

33 Galectin-1 causes degeneration of neuronal processes

34 Similar results with hes lines

35 Development according to Waddington 1957 Hochedlinger and Path (2009) Development

36 Differentiation commitment is reversible

37 A simple TF cocktail is sufficient Takahashi, K. & Yamanaka, S. (2006) Cell 126,

38 Reprogramming achieved with somatic cells from the 3 germ layers

39 How does reprogramming work?

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46 Methods: Summary