Spontaneous in contrast to CD95-induced neutrophil apoptosis is independent of caspase activity.

Abstract

BACKGROUND:

The influence of caspase inhibitors on spontaneous and on CD95-triggered apoptosis was investigated in neutrophils from healthy volunteers and compared with neutrophils from patients with severe sepsis.

METHODS:

To further elucidate the mechanisms of neutrophil apoptosis, isolated neutrophils from healthy volunteers (n = 9) were either stimulated with the agonistic anti-CD95 antibody (100 ng/mL) or left unstimulated in the presence or absence of the caspase inhibitors zIETD-fmk (10 micromol/L), zDEVD-fmk (10 micromol/L), or zVAD-fmk (20 micromol/L). Apoptosis was determined by measuring DNA fragmentation and Annexin-V binding in FACS, and caspase-3-like activity by DEVD-afc cleavage assay. Results were compared with those from patients with severe sepsis (n = 15).

RESULTS:

Reduced spontaneous neutrophil apoptosis in patients with sepsis (-48.7%) was completely restored by incubation with agonistic anti-CD95 antibody (p < 0.05). Inhibition of caspases did not influence spontaneous neutrophil apoptosis in both groups. However, zVAD-fmk reduced anti-CD95 antibody-induced apoptosis in neutrophils from controls by -22.6% (p < 0.05) and in patients with sepsis by -43.1% (p < 0.05).

CONCLUSION:

These results indicate that spontaneous in contrast to CD95-induced neutrophil apoptosis is independent of caspase activity.

• Authors: L Härter, M Keel, H Hentze, U Steckholzer, U Ungethüm, O Trentz, W Ertel
• Journal: The Journal of trauma (J Trauma) Vol. 50 Issue 6 Pg. 982-8 (Jun 2001) ISSN: 0022-5282 [Print] United States
• PMID: 11426111 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Amino Acid Chloromethyl Ketones
• Cysteine Proteinase Inhibitors
• benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone
• fas Receptor
• Caspases

Topics

• Amino Acid Chloromethyl Ketones (pharmacology)
• Apoptosis
• Case-Control Studies
• Caspases (metabolism)
• Cysteine Proteinase Inhibitors (pharmacology)
• Enzyme Activation
• Humans
• Neutrophils (metabolism, pathology)
• Sepsis (immunology, metabolism)
• fas Receptor (metabolism)