Novel role of group VIB Ca2+-dependent phospholipase A2γ in leukocyte-endotherial cell interaction in acute inflammation: an intravital microscopic study in rat mesentery.
Novel role of group VIB Ca2+-dependent phospholipase A2γ in leukocyte-endotherial cell interaction in acute inflammation: an intravital microscopic study in rat mesentery.
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VIB 组 Ca2+ 依赖性磷脂酶 A2γ 在急性炎症白细胞-内皮细胞相互作用中的新作用：大鼠肠系膜的活体显微镜研究。
DOI：
10.1097/ta.0000000000000845
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
and Yasuhiro Otomo
中科院分区：
文献类型：
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作者：
Mitsuaki Kojima;Junichi Aiboshi;Masahiro Shibata;Tetsuyuki Kobayashi;and Yasuhiro Otomo
磷脂酶a2 （PLA 2）与多形核中性粒细胞(PMN) -内皮细胞相互作用相关的多种炎症过程有关。然而，pla2的相互作用和致病亚型的细胞和分子机制仍然难以捉摸。此外，我们最近发现，钙不依赖的ppla 2 γ (iPLA 2 γ)，而不是细胞质ppla 2 (cPLA 2)，负责人类PMN的细胞毒性功能，包括呼吸爆发、脱颗粒和趋化。因此，我们假设ipl2γ是PMN招募级联进入炎症部位的先决条件。本研究的目的是阐明三种主要磷脂酶a2， iPLA 2， cPLA 2和分泌PLA 2在体内和体外响应明确的刺激时对白细胞滚动和粘附以及β 2整合素表面表达的作用。方法用选择性ipla2 β、ipla2 γ、cpa2或分泌型ppa2的ppa2抑制剂预处理Wistar小鼠。用活体显微镜定量观察血小板活化因子（PAF）灌注的肠系膜小静脉中白细胞滚动/粘附情况。此外，分离的人pmn或全血与每种PLA 2抑制剂孵育，然后用甲氧基-蛋氨酸-亮基-苯丙氨酸（fMLP）或PAF活化。通过计数与纯化纤维蛋白原结合的细胞来评估PMN粘附性，通过流式细胞术检测淋巴细胞功能相关抗原1和巨噬细胞抗原1 （Mac-1）的表面表达。结果ipla2 γ特异性抑制剂在体内和体外几乎完全抑制fMLP/ paf诱导的白细胞粘附，并使fMLP/ paf刺激的Mac-1表面表达分别降低60%和95%。相反，其他抑制剂不影响这些细胞功能。结论PAF/fMLP作用下，pla2 γ参与了体外和体内白细胞/PMN的粘附，并参与了体外Mac-1的上调。因此，这种酶可能是PMN招募级联的主要调节因子。
BACKGROUNDPhospholipase A 2 (PLA 2) is associated with a variety of inflammatory processes related to polymorphonuclear neutrophil (PMN)–endothelial cell interactions. However, the cellular and molecular mechanisms underlying the interactions and the causative isoform (s) of PLA 2 remain elusive. In addition, we recently showed that calcium-independent PLA 2 γ (iPLA 2 γ), but not cytosolic PLA 2 (cPLA 2), is responsible for the cytotoxic functions of human PMN including respiratory bursts, degranulation, and chemotaxis. We therefore hypothesized that iPLA 2 γ is a prerequisite for the PMN recruitment cascade into the site of inflammation. The aim of this study was to elucidate the roles of the three major phospholipases A 2, iPLA 2, cPLA 2 and secretory PLA 2, in leukocyte rolling and adherence and in the surface expression of β 2-integrins in vivo and in vitro in response to well-defined stimuli.METHODSMale Wistar rats were pretreated with PLA 2 inhibitors selective for iPLA 2 β, iPLA 2 γ, cPLA 2, or secretory PLA 2. Leukocyte rolling/adherence in the mesenteric venules superfused with platelet-activating factor (PAF) were quantified by intravital microscopy. Furthermore, isolated human PMNs or whole blood were incubated with each PLA 2 inhibitor and then activated with formyl-methionyl-leucyl-phenylalanine (fMLP) or PAF. PMN adherence was assessed by counting cells bound to purified fibrinogen, and the surface expression of lymphocyte function-associated antigen 1 and macrophage antigen 1 (Mac-1) was measured by flow cytometry.RESULTSThe iPLA 2 γ-specific inhibitor almost completely inhibited the fMLP/PAF-induced leukocyte adherence in vivo and in vitro and also decreased the fMLP/PAF-stimulated surface expression of Mac-1 by 60% and 95%, respectively. In contrast, the other inhibitors did not affect these cellular functions.CONCLUSIONiPLA 2 γ seems to be involved in leukocyte/PMN adherence in vivo and in vitro as well as in the up-regulation of Mac-1 in vitro in response to PAF/fMLP. This enzyme is therefore likely to be a major regulator in the PMN recruitment cascade.