Differential behavior of sPLA2-V and sPLA2-X in human neutrophils

I. Solodkin-Szaingurten, R. Levy, N. Hadad

Research output: Contribution to journalArticlepeer-review

6 Scopus citations

Abstract

Neutrophils and differentiated PLB-985 cells contain various types of PLA2s including the 85 kDa cytosolic PLA2 (cPLA2), Ca2+-independent PLA2 (iPLA2) and secreted PLA2s (sPLA2s). The present study focuses on the behavior of sPLA2s in neutrophils and PLB cells and their relationship to cPLA2α. The results of the present research show that the two types of sPLA2 present in neutrophils, sPLA2-V and sPLA2-X, which are located in the azurophil granules, are differentially affected by physiological stimuli. While sPLA2-V is secreted to the extacellular milieu, sPLA2-X is detected on the plasma membranes after stimulation. Stimulation of neutrophils with formyl-Met-Leu-Phe (fMLP), opsonized zymosan (OZ) or A23187 resulted in a different kinetics of sPLA2 secretion as detected by its activity in the neutrophil supernatants. Neutrophil priming by inflammatory cytokines or LPS enhanced sPLA2 activity detected in the supernatant after stimulation by fMLP. This increased activity was due to increased secretion of sPLA2-V to the supernatant and not to release of sPLA2-X. sPLA2 in granulocyte-like PLB cells exhibit identical characteristics to neutrophil sPLA2, with similar activity and optimal pH of 7.5. Granulocyte-like cPLA2α-deficient PLB cells serve as a good model to study whether sPLA2 activity is regulated by cPLA2α. Secretion and activity of sPLA2 were found to be similar in granulocyte-like PLB cells expressing or lacking cPLA2α, indicating that they are not under cPLA2α regulation.

Original languageEnglish
Pages (from-to)155-163
Number of pages9
JournalBiochimica et Biophysica Acta - Molecular and Cell Biology of Lipids
Volume1771
Issue number2
DOIs
StatePublished - 1 Feb 2007

Keywords

  • Granulocyte-like PLB cell
  • Neutrophils
  • PLB-985 cells
  • Secreted PLA

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