Calpain and calpastatin regulate neutrophil apoptosis.
J Cell Physiol
; 178(3): 311-9, 1999 Mar.
Article
in En
| MEDLINE
| ID: mdl-9989777
ABSTRACT
The average polymorphonuclear neutrophil (PMN) lives only a day and then dies by apoptosis. We previously found that the calcium-dependent protease calpain is required for apoptosis in several mouse models of cell death. Here we identify calpain, and its endogenous inhibitor calpastatin, as regulators of human neutrophil apoptosis. Cell death triggered by the translation inhibitor cycloheximide is calpain-dependent, as evidenced using either a calpain active site inhibitor (N-acetyl-leucyl-leucyl-norleucinal) or agents that target calpain's calcium binding sites (PD150606, PD151746). No significant effect on cycloheximide-triggered apoptosis was found by using inhibitors of the proteasome or of other papain-like cysteine proteases, providing further evidence that the active site calpain inhibitor prevents apoptosis via its action on calpain. In addition, we find that potentiation of calpain activity by depleting its endogenous inhibitor, calpastatin, is sufficient to cause apoptosis of neutrophils. Nevertheless, apoptosis signalled via the Fas antigen proceeds regardless of the presence of calpain inhibitor. These experiments support a growing body of work, indicating an upstream regulatory role for calpain in many, but not all, forms of apoptotic cell death. They also identify calpastatin as a participant in apoptotic cell death and suggest that for at least one cell type, a decrease in calpastatin is a sufficient stimulus to initiate calpain-dependent apoptosis.
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Acrylates
/
Calcium-Binding Proteins
/
Calpain
/
Cysteine Proteinase Inhibitors
/
Apoptosis
/
Neutrophils
Limits:
Adult
/
Animals
/
Humans
Language:
En
Journal:
J Cell Physiol
Year:
1999
Document type:
Article
Affiliation country:
United States