CRICM, UPMC-Paris 6; Inserm U975; CNRS 7225 Hôpital de la Salpêtrière

Présentation au sujet: "CRICM, UPMC-Paris 6; Inserm U975; CNRS 7225 Hôpital de la Salpêtrière"— Transcription de la présentation:

1 CRICM, UPMC-Paris 6; Inserm U975; CNRS 7225 Hôpital de la Salpêtrière
Fonction et Développement des Oligodendrocytes B. Zalc CRICM, UPMC-Paris 6; Inserm U975; CNRS 7225 Hôpital de la Salpêtrière

2 1. Généralités sur la myéline
2. Fonctions de la gaine de myéline 3. Origine des Oligodendrocytes 4. Migration des Oligodendrocytes 5. Développement des Oligodendrocytes

3 1) Généralités sur la myéline

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7 Composition biochimique de la myéline

8 (Zalc & Lubetzki, in Multiple Sclerosis, C. Raine ed, 2008)

9 2) Fonctions de la gaine de myéline

10 Or radially into the membrane Current can go forward axially
cm rm Increase radius  ri  Na+ + + + + + + + + + + + + Or radially into the membrane Current can go forward axially

11 1 Unmyelinated

12 From Peles and Salzer, 2000

13 Latin: saltare = to jump
Saltatory conduction Impulse jumps from node to node Latin: saltare = to jump : Na channels

14 Myelinated Unmyelinated Myelination favoured if diameter > 1 micron

15 Molecular organization of CNS nodes of Ranvier and paranodes
Glial Cell Contactin Node Nfasc155 Nfasc186 NrCAM Paranode Nav Caspr Contactin 4.1B IIII- Spectrin AnkyrinB Axon IV spectrin AnkyrinG From Brophy, 2010

16 3) Origine des oligodendrocytes

17 (Zalc & Colman, Science, 2000)

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21 Motor Neurons Dorsalizing factors (BMPs, Wnt, dorsalin…) After E11.5
E8.5-E11.5 Pax6 Olig1/2 Irx3 p3 pMN p2 p1 p0 pD p3 pMN p2 p1 p0 pD Olig1/2 Irx3 Pax6 Oligodendrocytes PDGFRa + Motor Neurons Nkx2.2 Ngn2 Nkx2.2 Ngn3 V3 Ventralizing factor (Sonic hedgehog, …?) Lu et al.,2000, Zhou et al., 2001, Zhou et al. 2002, Fu et al., 2002

22 The origin of oligodendrocytes in the rodent spinal cord
early oligodendrocytes ~70-80% of the total late oligodendrocytes ~10-20% of the total early oligodendrocytes ~10-20% of the total N. Tekki-Kessaris

23 Tekki-Kessaris & Richardson, 2006

24 4) Migration des oligodendrocytes

25 Olivier et al., Development, 2001
Heterotopic grafts

26 • Expression of receptors by OPCs
Spassky et al., J. Neurosci. 2002 • Expression of receptors by OPCs class 3 Sema Neuropilin and Neuropilin-2 /Sema 3A /Sema 3F Netrin-1 DCC and Unc5h1 (Embryonic) (Post natal) • Expression of factors in the context of the optic nerve Sema 3A Sema 3F Netrin-1

27 5) Développement des oligodendrocytes

28 Oligodendrocyte Precursor cell
A2B5 GD3 NG2 Adult Précursor Oligodendrocyte Progenitor