Membrane permeabilization by thrombin-induced platelet microbicidal protein 1 is modulated by transmembrane voltage polarity and magnitude.
Membrane permeabilization by thrombin-induced platelet microbicidal protein 1 is modulated by transmembrane voltage polarity and magnitude.
复制标题
凝血酶诱导的血小板杀微生物蛋白 1 的膜透化作用受跨膜电压极性和幅度的调节。
DOI：
10.1128/iai.67.5.2475-2481.1999
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发表时间：
1999
期刊：
影响因子：
--
通讯作者：
Yeaman,MR
中科院分区：
文献类型：
--
作者：
Koo,SP;Bayer,AS;Kagan,BL;Yeaman,MR
凝血酶诱导的血小板杀微生物蛋白1（tPMP-1）是兔血小板在体外暴露于凝血酶时产生的一种小的阳离子肽。它对包括金黄色葡萄球菌在内的广谱细菌和真菌病原体具有有效的杀微生物活性。先前涉及全葡萄球菌细胞和平面脂质双层（作为人工细菌膜模型）的体外研究表明，通过tPMP-1的膜透化是电压依赖性的（S. P. Koo，M. R. Yeaman和A. S.拜耳，感染。Immun. 64：3758-3764，1996; M. R. Yeaman，A. S.拜尔，S。P. Koo，W. Foss和P.M. Sullam，J. Clin. Investig. 101：178-187，1998）。因此，本研究的目的是通过使用人工平面脂质双层膜来具体表征与tPMP-1的膜透化相关的电生理事件。我们评估了在不同浓度的tPMP-1（范围1至100 ng/ml）加入到膜的侧边时，跨膜电压极性和幅度对tPMP-1膜透化的启动和调节的影响。在所有测试浓度下，tPMP-1诱导的膜透化的发生率在−90 mV下比在+90 mV下更频繁。值得注意的是，1 ng/ml tPMP-1导致的膜透化作用在−90 mV下成功启动，但在+90 mV下未成功启动。此外，在各种条件下诱导tPMP-1活性的平均起始时间相当。正在进行的膜透化的调制依赖于电压和tPMP-1浓度。低浓度（1 ng/ml）的tPMP-1引起的膜透化作用与跨-负电压直接相关，而高浓度（100 ng/ml）的tPMP-1引起的电导则更多地依赖于跨-正电压。总的来说，这些数据表明，tPMP-1在细菌细胞质膜上的杀微生物活性的机制可能涉及膜透化的不同诱导和繁殖阶段，而膜透化又受到跨膜电位以及肽浓度的调节。
Thrombin-induced platelet microbicidal protein 1 (tPMP-1) is a small, cationic peptide generated from rabbit platelets when they are exposed to thrombin in vitro. It has potent microbicidal activity against a broad spectrum of bacterial and fungal pathogens, includingStaphylococcus aureus. Previous in vitro studies involving whole staphylococcal cells and planar lipid bilayers (as artificial bacterial membrane models) suggested that membrane permeabilization by tPMP-1 is voltage dependent (S.-P. Koo, M. R. Yeaman, and A. S. Bayer, Infect. Immun. 64:3758–3764, 1996; M. R. Yeaman, A. S. Bayer, S. P. Koo, W. Foss, and P. M. Sullam, J. Clin. Investig. 101:178–187, 1998). Thus, the aims of the present study were to specifically characterize the electrophysiological events associated with membrane permeabilization by tPMP-1 by using artificial planar lipid bilayer membranes. We assessed the influence of transmembrane voltage polarity and magnitude on the initiation and modulation of tPMP-1 membrane permeabilization at various concentrations of tPMP-1 (range, 1 to 100 ng/ml) added to thecisside of the membranes. The incidence of membrane permeabilization induced by tPMP-1 at all of the concentrations tested was more frequent at −90 mV than at +90 mV. It is noteworthy that membrane permeabilization due to 1-ng/ml tPMP-1 was successfully initiated at −90 mV but not at +90 mV. Further, the mean onset times of induction of tPMP-1 activity were comparable under the various conditions. Modulation of ongoing membrane permeabilization was dependent on voltage and tPMP-1 concentration. Membrane permeabilization at a low tPMP-1 concentration (1 ng/ml) was directly correlated withtrans-negative voltages, while a higher tPMP-1 concentration (100 ng/ml) induced conductance which was more dependent ontrans-positive voltages. Collectively, these data indicate that the mechanism of tPMP-1 microbicidal activity at the bacterial cytoplasmic membrane may involve distinct induction and propagation stages of membrane permeabilization which, in turn, are modulated by transmembrane potential, as well as peptide concentration.