| Project/Area Number |
14570201
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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 |
Experimental pathology
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| Research Institution | Tokai University |
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Principal Investigator |
SUSUMU Takekoshi Tokai University, School of Medicine, Assistant Professor, 医学部, 講師 (70216878)
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| Co-Investigator(Kenkyū-buntansha) |
OSAMURA Yoshiyuki Tokai University, School of Medicine, Professor, 医学部, 教授 (10100992)
TAKIZAWA Shunya Tokai University, School of Medicine, Associate Professor, 医学部, 助教授 (70197234)
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| Project Period (FY) |
2002 – 2003
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| Project Status |
Completed (Fiscal Year 2003)
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| Budget Amount *help |
¥2,900,000 (Direct Cost: ¥2,900,000)
Fiscal Year 2003: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 2002: ¥1,800,000 (Direct Cost: ¥1,800,000)
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| Keywords | diacylglycerol / protein kinase C / lipid peroxidation / signal transduction / oxidative stress / MAP kinase / BIA core / glutathione peroxidase / signal tansduction / neuron / brain |
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| Research Abstract |
Protein kinase C (PKC) plays an important role in the regulation of numerous intracellular functions. We previously reported that oxidized diacylglycerol (DAG-OOH) exhibited outstanding activation of PKC. Among 7 PKC isoforms present in rat brain, only PKC α and PKC δ were specifically activated by DAG-OOH. We used an adenovirus vector system which allows transiently expression of PKC α and PKC δ gene at a high level in neuronal cells established from 18-day rat fetus cerebral cortex (PN cells). The PKC δ-overexpressed PN cells exhibited neuritic thinning and characteristic beading by the exposure to DAG-OOH. These changes were however not observed in the PKC α and PKC δ kinase negative-overexpressed PN cells. Both routine electron microscopic observation and tubulin immunohistochemistry revealed the microtubule (MT) disassembly in the "beaded" lesions. This MT damage may be caused by the stagnation of the neurosecretory vesicles in the "beaded" lesions. MT damage could be induce by th
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e over-phosphorylation of tau (microtubule associated protein). Therefore, we investigated the effect of DAG-OOH treatment on MAP kinase pathway and tau protein in the PKC δ-overexpressed PN cells. DAG-OOH induced a time dependent increase in the activation of MAP kinase pathway (Raf, MEK and ERK) and also the phosphorylation of tau protein. In DAG-OOH-injected rat brain, obvious neuronal cell injury and cell death was observed. Furthermore, we explored the protective drug against DAG-OOH-induced neuronal cell injury. Ebselen, a seleno-organic compound with glutathione peroxidase-like activity, inhibited the DAG-induce neuronal cell injury remarkably. To demonstrate the importance of glutathione peroxidase for the protection of neuron from DAG-OGH, selenium (-) and (+) rat were employed. As a result, DAG-OOH-induced cell injury has been seen only in selenium deficient rat neuron, which clearly indicate the defensive effect of glutathione peroxidase against DAG-OOH action. Finally, the molecular mechanism for the activation of PKC by DAG-OGH was studied using BIAcore machinery which can, analysis the bio-molecular binding. The high-affinity interaction between PKC and DAG-OOH was clearly proved. These results strongly suggest that DAG-OOH plays a key role for the neuronal cell injury and cell death elicited by oxidative stress concerning in neuro-degenerative disorders such as Alzheimer and Parkinson disease. Less
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