Document Detail


Spontaneous human monocyte apoptosis utilizes a caspase-3-dependent pathway that is blocked by endotoxin and is independent of caspase-1.
MedLine Citation:
PMID:  10438906     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Apoptosis is an important mechanism for regulating the numbers of monocytes and macrophages. Caspases (cysteine-aspartate-specific proteases) are key molecules in apoptosis and require proteolytic removal of prodomains for activity. Caspase-1 and caspase-3 have both been connected to apoptosis in other model systems. The present study attempted to delineate what role these caspases play in spontaneous monocyte apoptosis. In serum-free conditions, monocytes showed a commitment to apoptosis as early as 4 h in culture, as evidenced by caspase-3-like activity. Apoptosis, as defined by oligonucleosomal DNA fragmentation, was prevented by a generalized caspase inhibitor, z-VAD-FMK, and the more specific caspase inhibitor, z-DEVD-FMK. The caspase activity was specifically attributable to caspase-3 by the identification of cleavage of procaspase-3 to active forms by immunoblots and by cleavage of the fluorogenic substrate DEVD-AFC. In contrast, a caspase-1 family inhibitor, YVAD-CMK, did not protect monocytes from apoptosis, and the fluorogenic substrate YVAD-AFC failed to show an increase in activity in apoptotic monocytes. When cultured with LPS (1 microgram/ml), monocyte apoptosis was prevented, as was the activation of caspase-3. Unexpectedly, LPS did not change baseline caspase-1 activity. These findings link spontaneous monocyte apoptosis to the proteolytic activation of caspase-3.
Authors:
R J Fahy; A I Doseff; M D Wewers
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Journal of immunology (Baltimore, Md. : 1950)     Volume:  163     ISSN:  0022-1767     ISO Abbreviation:  J. Immunol.     Publication Date:  1999 Aug 
Date Detail:
Created Date:  1999-09-09     Completed Date:  1999-09-09     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  2985117R     Medline TA:  J Immunol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1755-62     Citation Subset:  AIM; IM    
Affiliation:
Department of Internal Medicine, Division of Pulmonary and Critical Care, The Heart and Lung Institute, Ohio State University, Columbus, OH 43210, USA.
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MeSH Terms
Descriptor/Qualifier:
Apoptosis / immunology*
Caspase 1 / physiology*
Caspase 3
Caspases / antagonists & inhibitors,  blood,  physiology*
Cell Survival / immunology
Enzyme Activation / immunology
Humans
Interleukin-1 / metabolism
Lipopolysaccharides / pharmacology*
Monocytes / cytology*,  enzymology*,  immunology
Protein Precursors / metabolism
Signal Transduction / immunology
Grant Support
ID/Acronym/Agency:
HL40871/HL/NHLBI NIH HHS; HL53229/HL/NHLBI NIH HHS
Chemical
Reg. No./Substance:
0/Interleukin-1; 0/Lipopolysaccharides; 0/Protein Precursors; EC 3.4.22.-/CASP3 protein, human; EC 3.4.22.-/Caspase 3; EC 3.4.22.-/Caspases; EC 3.4.22.36/Caspase 1

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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