The major outer sheath protein of Treponema denticola selectively inhibits Rac1 activation in murine neutrophils
The major outer sheath protein of Treponema denticola selectively inhibits Rac1 activation in murine neutrophils
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DOI：
10.1111/j.1462-5822.2007.01045.x
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发表时间：
2008-02-01
影响因子：
3.4
通讯作者：
Ellen, Richard P.
中科院分区：
文献类型：
--
作者：
Magalhaes, Marco A. O.;Sun, Chun Xiang;Ellen, Richard P.
密螺旋体denticola主要外鞘蛋白（Msp）在体外抑制中性粒细胞趋化性，但关键的调节机制尚未确定。由于Rac小gtpase在化学引诱剂的作用下调节定向迁移，因此我们的目的是分析Msp对甲氧基-蛋氨酸-亮氨酸-苯丙氨酸（fMLP）介导的中性粒细胞极化和小鼠中性粒细胞Rac活化的影响。Msp预处理中性粒细胞抑制fMLP的极化和趋化迁移。采用p21结合域（PBD）下拉法检测小gtpase的激活，然后采用单克隆抗rac1、抗rac2、抗cdc42和抗rhoa抗体进行Western分析。富集的天然Msp以浓度依赖性的方式选择性抑制fmlp刺激的Rac1激活，但不影响Rac2、cdc42或RhoA的激活。用表达荧光探针PAK-PBD-YFP和PH-AKT-RFP的载体转染小鼠中性粒细胞，测定Msp对活化的Rac和PI3激酶产物定位的影响。实时共聚焦图像显示，暴露于fMLP后，Msp抑制活化Rac和pi3激酶产物的极化积累。结果表明，齿齿苋Msp对中性粒细胞极性的抑制可能是由于选择性抑制了Rac1通路。
Treponema denticola major outer sheath protein (Msp) inhibits neutrophil chemotaxis in vitro, but key regulatory mechanisms have not been identified. Because the Rac small GTPases regulate directional migration in response to chemoattractants, the objective was to analyse the effects of Msp on formyl-methionyl-leucyl-phenylalanine (fMLP)-mediated neutrophil polarization and Rac activation in murine neutrophils. Msp pretreatment of neutrophils inhibited both polarization and chemotactic migration in response to fMLP. Activation of small GTPases was measured by p21 binding domain (PBD) pulldown assays, followed by Western analysis, using monoclonal anti-Rac1, anti-Rac2, anti-cdc42 and anti-RhoA antibodies. Enriched native Msp selectively inhibited fMLP-stimulated Rac1 activation in a concentration-dependent manner, but did not affect Rac2, cdc42 or RhoA activation. Murine neutrophils transfected with vectors expressing fluorescent probes PAK-PBD-YFP and PH-AKT-RFP were used to determine the effects of Msp on the localization of activated Rac and PI3 kinase products. Real-time confocal images showed that Msp inhibited the polarized accumulation of activated Rac and PI3-kinase products upon exposure to fMLP. The findings indicate that T. denticola Msp inhibition of neutrophil polarity may be due to the selective suppression of the Rac1 pathway.