Differential behavior of sPLAb>2b>-V and sPLAb>2b>-X in human neutrophils

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• 作者：I. Solodkin-Szaingurten ; R. Levy ; N. Hadad
• 关键词：Neutrophils ; PLB-985 cells ; Granulocyte-like PLB cell ; Secreted PLAb>2b>
• 刊名：Biochimica et Biophysica Acta (BBA)/Molecular and Cell Biology of Lipids
• 出版年：2007
• 期刊代码：18_13881981
• 类别：bio
• 出版时间：February 2007
• 卷：1771
• 期：2
• 页码：155-163
• 文件大小：662 K

摘要

Neutrophils and differentiated PLB-985 cells contain various types of PLAb>2b>s including the 85 kDa cytosolic PLAb>2b> (cPLAb>2b>), Ca²⁺-independent PLAb>2b> (iPLAb>2b>) and secreted PLAb>2b>s (sPLAb>2b>s). The present study focuses on the behavior of sPLAb>2b>s in neutrophils and PLB cells and their relationship to cPLAb>2b>b1;. The results of the present research show that the two types of sPLAb>2b> present in neutrophils, sPLAb>2b>-V and sPLAb>2b>-X, which are located in the azurophil granules, are differentially affected by physiological stimuli. While sPLAb>2b>-V is secreted to the extacellular milieu, sPLAb>2b>-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 sPLAb>2b> secretion as detected by its activity in the neutrophil supernatants. Neutrophil priming by inflammatory cytokines or LPS enhanced sPLAb>2b> activity detected in the supernatant after stimulation by fMLP. This increased activity was due to increased secretion of sPLAb>2b>-V to the supernatant and not to release of sPLAb>2b>-X. sPLAb>2b> in granulocyte-like PLB cells exhibit identical characteristics to neutrophil sPLAb>2b>, with similar activity and optimal pH of 7.5. Granulocyte-like cPLAb>2b>b1;-deficient PLB cells serve as a good model to study whether sPLAb>2b> activity is regulated by cPLAb>2b>b1;. Secretion and activity of sPLAb>2b> were found to be similar in granulocyte-like PLB cells expressing or lacking cPLAb>2b>b1;, indicating that they are not under cPLAb>2b>b1; regulation.