Forebrain ependymal cells are Notch-dependent and generate neuroblasts and astrocytes after stroke (Nat Neurosci, 2009, 12:259-267)

報告日期: 2010/12/24
報告時間: 15:10/16:00
報告學生: 吳承寯
講評老師: 曾淑芬

Full Text:

Forebrain ependymal cells are Notch-dependent and generate neuroblasts and astrocytes after stroke
Marie Carle´n1 , Konstantinos Meletis, Christian Go¨ritz, Vladimer Darsalia, Emma Evergren, Kenji Tanigaki, Mario Amendola, Fanie Barnabe´-Heider1, Maggie S Y Yeung1, Luigi Naldini6, Tasuku Honjo,Zaal Kokaia, Oleg Shupliakov, Robert M Cassidy, Olle Lindvall & Jonas Frise´n
NATURE NEUROSCIENCE 2009, V.12 ( 3 ) P 259-67.
Speaker : Cheng-Jiun Wu ( 吳承寯 )
Commentator : Shun-Fen Tzeng Ph.D. ( 曾淑芬老師 )
Time : 12/24/2010
Place : Room 602
    Ependyma is a membrane around the ventricular system and regulates the production of CSF in the brain and the spinal cord. The previous studies papers reported ependymal cells may serve as neural stem cell niche to generate neuroblasts and astrocytes in reponse to brain injury. But the features of stem cells on forebrain ependymal cells are still controversial. On the other hand, Notch signaling plays an important role in regulating cell development, especially in maintaining stem cell characters. However, how Notch signaling regulate ependymal cell in homeostasis and stroke insult also has not been disclosed. In this study, ependymal cells are quiescent and not contribute to adult neurogenesis. Nevertheless, stroke insult induces ependymal cells differentiation into neuroblasts and astrocytes, moreover, Notch signaling plays a key mediator in this phenomenon. Inhibition of this pathway in uninjured animals allowed ependymal cells to enter the cell cycle and produce olfactory bulb neurons, whereas forced Notch signaling was sufficient to block the ependymal cell response to stroke. Ependymal cells were depleted by stroke and failed to self-renew sufficiently to maintain their own population. Thus, although ependymal cells act as primary cells in the neural lineage to produce neurons and glial cells after stroke, they do not fulfill defining criteria for stem cells under these conditions and instead serve as a reservoir that is recruited by injury. 
References :
1.     Mirzadeh, al., Neural stem cells confer unique pinwheel architecture to the ventricular surface in neurogenic regions of the adult brain. Cell Stem Cell 3, 265–278 (2008).
2.     Louvi, A. & Artavanis-Tsakonas, S. Notch signaling in vertebrate neural development.
Nat. Rev. Neurosci. 7, 93–102 (2006).