2012 Fiscal Year Final Research Report
Mechanism of accelerating death of newborn neurons by ss-amyloid
| Project/Area Number |
22500347
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Neurochemistry/Neuropharmacology
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| Research Institution | Tokyo Metropolitan Geriatric Hospital and Institute of Gerontology |
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Principal Investigator |
UCHIDA Yoko 地方独立行政法人東京都健康長寿医療センター(東京都健康長寿医療センター研究所), 東京都健康長寿医療センター研究所, 研究員 (60133633)
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| Co-Investigator(Renkei-kenkyūsha) |
GOMI Fujiya 地方独立行政法人東京都健康長寿医療センター(東京都健康長寿医療センター研究所), 東京都健康長寿医療センター研究所, 研究員 (40205620)
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| Project Period (FY) |
2010 – 2012
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| Keywords | β-アミロイド / 神経新生 |
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| Research Abstract |
In Alzheimer's disease (AD), immature neuronal marker proteins increased in brain. However, the increased neurogenesis is not sufficient to repair the nervous system because progressive neuronal loss occurs in AD brain. Alteration of microenvironment in AD brain may affect the fate of immature neurons. Ss-amyloid (Ass) plays an important role in the early pathogenesis of AD. It is reasonable to speculate Ass alters the brain microenvironment to make it toxic to newborn neurons. To address these issues, we tried to identify the genes to inhibit survival of newborn neurons in Ass-induced genes. Among 7 Ass-induced genes, only Chat (Cas/HEF1-associated signal transducer) accelerated death of newborn neurons. Other 6 genes promoted neuronal survival or did not affect on neuronal survival. Next, we focused on Chat gene and tried to clarify toxic mechanism to newborn neurons. The results are follows :
(1) C-terminal portion of Chat is necessary to induce toxicity in newborn neurons.
(2) C-terminal portion of Chat have the binding domain to Cas protein family. However, co-transfection of Cas proteins (p130Cas and NEDD9) and Chat into newborn neurons did not accelerate neuronal death. The mutant Chat, which does not bind to Cas proteins, also accelerated neuronal death. These results suggests that the binding of unknown proteins to Chat C-terminal portion (Chat C) other than Cas binding site might be necessary to induce toxicity in newborn neurons. Finally we tried to identify the proteins that bind to Chat C and accelerate death of newborn neurons. A GST-Chat C fusion protein was constructed and purified. The lysate from cultured cortical neurons was incubated with a GST-Chat C fusion protein. Pull downed proteins were subjected to SDS-PAGE and analyzed with nanoLC-MS/MS. We could not identify any binding proteins to GST-Chat C fusion protein. It could not rule out that homopolymer formation of Chat C would induce neurotoxicity to newborn neurons.
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