2001 Fiscal Year Final Research Report Summary
MOLECULAR CELL BIOLOGICAL STUDY OF CELL DEATH INDUCED CATHEPSIN D
| Project/Area Number |
11680738
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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 |
Nerve anatomy/Neuropathology
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| Research Institution | Osaka University |
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Principal Investigator |
ISHIHARA Kyoko Osaka University Graduate School of Medicine, Department of Cell Biology and Neuroscience, Assistant Professor, 医学系研究科, 助手 (30303944)
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| Co-Investigator(Kenkyū-buntansha) |
KAMETAKA Satoshi Osaka University Graduate School of Medicine, Department of Cell Biology and Neuroscience, Assistant Professor, 医学系研究科, 助手 (10303950)
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| Project Period (FY) |
1999 – 2001
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| Keywords | Lysosome / Proteinase / Cathepsin B / Cathepsin D / CNS / Mitochondria / Ceroid lipofuscin / Knockout mouse |
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| Research Abstract |
In order to analyze the cell death pathway regulated by lysosomal cathepsins B and D, we used cathepsin D-deficient (CD-/-) mice. CD-/- mice have been shown to manifest seizures and become blind near the terminal stage [approximately postnatal day (P) 26]. We therefore examined the morphological, immunocytochemical, and biochemical features of CNS tissues of these mice. By electron microscopy, autophagosome/autolysosome-like bodies containing part of the cytoplasm, granular osmiophilic deposits, and fingerprint profiles were demostrated in the neuronal perikarya of CD-/- mouse brains after P20. Subunit c of mitochondrial ATP synthase was found to accumulate in the lysosomes of neurons, although the activity of tripeptidyl peptidase-I significantly increased in the brains. These results suggest that the CNS neurons in CD-/- mice show a new form of lysosomal accumulation disease with a phenotype resembling neuronal ceroid lipofuscinosis. Moreover, the retinal layers of CD-/- mice became thinner than those of the control littermates, particularly, the photoreceptor layer was largely abolished, increasing in the number of TUNEL-positive nuclei in the outer nuclear layer. To identify substrates which are specifically cleaved by CD, we used CD-/- mouse embryonic fibroblasts (MEF). Mitochondria! MnSOD was identified as a possible substrate because of its accumulation in the cytoplasm of CD-/-MEF.
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