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[Cell death protection by anti-apoptotic factor]
Abstract:
Neurodegenerative disorders including ALS and Parkinson's disease are characterized by progressive loss of neuronal cell death. Apoptosis, a morphologically and biochemically defined form of cell death caused by active cellular signaling, has been long implicated in neurodegeneration. Recently, the basic molecular mechanism of apoptosis has been elucidated and a subset of cysteine proteases called caspases were shown to be the executioner of apoptosis. On the other hand, endogenous caspase inhibitor called inhibitor of apoptosis proteins (IAPs) were also identified. XIAP, the most potent apoptosis inhibitor among human IAPs, is shown to be direct and selective inhibitor for caspase-3, -7 and -9. We have very recently shown that XIAP has ubiquitin ligase activity which promotes the degradation of caspase-3 and this protease activity enhances the anti-apoptotic activity of XIAP. Regarding the involvement of apoptosis in neurodegenerative diseases, several lines of evidence indicated that caspases are involved in the pathogenesis of ALS and polyglutamine disease, suggesting the effectiveness of anti-apoptotic therapy for these diseases. Moreover, caspase-independent programmed cell death is also suggested to be involved in neurodegenerative disorders. Based on these findings, the therapeutic strategy for neurodegenerative disease should include both anti-apoptotic and anti-non-apoptotic cell death treatments.
Insights
Neurodegenerative diseases involve neuronal cell death, with apoptosis playing a key role. Therapies should target both apoptotic and non-apoptotic cell death pathways for effective treatment of conditions like ALS and Parkinson's disease.
Area of Science:
- Neuroscience
- Molecular Biology
- Biochemistry
Context:
- Neurodegenerative disorders, such as Amyotrophic Lateral Sclerosis (ALS) and Parkinson's disease, are characterized by progressive neuronal cell death.
- Apoptosis, a form of programmed cell death, is a significant factor in the pathogenesis of these diseases.
- Caspases are key executioner proteases in apoptosis, while Inhibitor of Apoptosis Proteins (IAPs) regulate this process.
Purpose:
- To elucidate the role of caspases and IAPs, specifically XIAP, in neurodegeneration.
- To investigate the ubiquitin ligase activity of XIAP in degrading caspase-3.
- To propose therapeutic strategies for neurodegenerative diseases based on understanding cell death mechanisms.
Summary:
- Apoptosis, mediated by caspases, is implicated in neurodegeneration. XIAP, a potent IAP, inhibits caspases and possesses ubiquitin ligase activity promoting caspase-3 degradation, thereby enhancing its anti-apoptotic function.
- Evidence suggests caspases are involved in ALS and polyglutamine diseases, indicating potential benefits of anti-apoptotic therapies.
- Caspase-independent programmed cell death pathways are also implicated, necessitating broader therapeutic approaches.
Impact:
- Findings highlight XIAP's dual role in apoptosis regulation, offering a potential therapeutic target.
- The study suggests that effective treatment for neurodegenerative diseases requires targeting both apoptotic and non-apoptotic cell death mechanisms.
- This research provides a basis for developing novel therapeutic strategies aimed at preventing neuronal loss in debilitating neurological conditions.