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Complement-derived anaphylatoxin C5a protects against glutamate-mediated neurotoxicity
H Osaka1, P Mukherjee, P S Aisen
1Department of Psychiatry, Mount Sinai School of Medicine, New York, New York 10029, USA.
Journal of Cellular Biochemistry
|May 13, 1999
Summary
The complement component C5a protects neurons from excitotoxicity, such as that induced by kainic acid. This study shows C5a reduces neuronal death by inhibiting caspase-3 activity, suggesting a novel noninflammatory role.
Area of Science:
- Neuroscience
- Immunology
- Cell Biology
Background:
- The complement system, particularly C5, plays a role in neuroprotection against excitotoxicity.
- C5a is a C5-derived anaphylatoxin with potential neuroprotective functions.
Purpose of the Study:
- To investigate the neuroprotective effects of C5a against kainic acid (KA)-induced neurodegeneration.
- To elucidate the underlying mechanisms of C5a's neuroprotective activity in vitro.
Main Methods:
- Intraventricular infusion of KA and C5a into adult mice to assess neurodegeneration.
- In vitro treatment of primary murine corticohippocampal neurons with C5a and glutamate.
- Assessment of neuronal apoptosis using morphological criteria and caspase-3 activity assays.
- Trypan blue exclusion assay to measure cell viability.
Main Results:
- Co-infusion of C5a with KA significantly reduced apoptotic neuronal death in the hippocampus.
- C5a treatment protected primary neurons from glutamate-induced excitotoxicity in vitro.
- C5a inhibited glutamate-mediated induction of caspase-3 activity.
- Reduced neuronal apoptosis was observed in vitro, mirroring in vivo findings.
Conclusions:
- C5a exhibits neuroprotective effects against excitotoxicity, including KA-induced neurodegeneration.
- C5a may exert its neuroprotective effects by partially inhibiting caspase-3 activity.
- These findings suggest a novel, noninflammatory role for C5a in modulating neuronal responses to excitotoxins.