Caspase‐3 activation in astrocytes following postnatal excitotoxic damage correlates with cytoskeletal remodeling but not with cell death or proliferation

L Acarin, S Villapol, M Faiz, TT Rohn, B Castellano… - Glia, 2007 - Wiley Online Library
Glia, 2007Wiley Online Library
Caspase‐3 has classically been defined as the main executioner of programmed cell death.
However, recent data supports the participation of this protease in non‐apoptotic cellular
events including cell proliferation, cell cycle regulation, and cellular differentiation. In this
study, astroglial cleavage of caspase‐3 was analyzed following excitotoxic damage in
postnatal rats to determine if its presence is associated with apoptotic cell death, cell
proliferation, or cytoskeletal remodeling. A well‐characterized in vivo model of excitotoxicity …
Abstract
Caspase‐3 has classically been defined as the main executioner of programmed cell death. However, recent data supports the participation of this protease in non‐apoptotic cellular events including cell proliferation, cell cycle regulation, and cellular differentiation. In this study, astroglial cleavage of caspase‐3 was analyzed following excitotoxic damage in postnatal rats to determine if its presence is associated with apoptotic cell death, cell proliferation, or cytoskeletal remodeling. A well‐characterized in vivo model of excitotoxicity was studied, where damage was induced by intracortical injection of N‐methyl‐D‐asparate (NMDA) in postnatal day 9 rats. Our results demonstrate that cleaved caspase‐3 was mainly observed in the nucleus of activated astrocytes in the lesioned hemisphere as early as 4 h postlesion and persisted until the glial scar was formed at 7–14 days, and it was not associated with TUNEL labeling. Caspase‐3 enzymatic activity was detected at 10 h and 1 day postlesion in astrocytes, and co‐localized with caspase‐cleaved fragments of glial fibrillary acidic protein (CCP‐GFAP). However, at longer survival times, when astroglial hypertrophy was observed, astroglial caspase‐3 did not generally correlate with GFAP cleavage, but instead was associated with de novo expression of vimentin. Moreover, astroglial caspase‐3 cleavage was not associated with BrdU incorporation. These results provide further evidence for a nontraditional role of caspases in cellular function that is independent of cell death and suggest that caspase activation is important for astroglial cytoskeleton remodeling following cellular injury. © 2007 Wiley‐Liss, Inc.
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