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对于包括铜绿假单胞菌在内的众多微生物而言,群体感应系统是细菌表达毒力因子的重要调节子.Las和Rhl是群体感应两个主要组成部分.Las和Rhl分别受自诱导剂N-3-氧化十二烷酰基-L-高丝氨酸内酯(3-oxo-C12-HSL)和N-丁酰-L-高丝氨酸内酯(C4-HSL)的影响.最近的研究进展显示群体感应分子尤其是3-oxo-C12-HSL具有调节宿主免疫系统的能力.本实验展示了3-oxo-C12-HSL可以诱导鼠源巨噬细胞(RAW264.7)的凋亡和吞噬作用.把合成的3-oxo-C12-HSL加入RAW264.7细胞培养基中,发现细胞生活力以一种依赖于3-oxo-C12-HSL的浓度(6.25 to 100μmol/L)和培养时间(2 to 24 h)的方式逐渐丢失.同样,我们观察到3-oxo-C12-HSL的细胞毒活性,用3-oxo-C12-HSL处理的细胞出现细胞形态上的改变,这一改变表明3-oxo-C12-HSL处理的细胞加速凋亡,这一点同时也被其他多个标准(caspases3、8和9,线粒体膜电位,磷脂酰丝氨酸的表达)所证实.中性红吞饮实验证明,3-oxo-C12-HSL会显著地减小RAW264.7细胞的吞噬能力(P<0.05).同时,高浓度的3-oxo-C12-HSL会降低RAW264.7细胞对铜绿假单胞菌的吞噬作用(P<0.001).这些数据表明3-oxo-C12-HSL能特异性地促进细胞凋亡的诱导和RAW264.7细胞吞噬能力的减小.这可能和3-oxo-C12-HSL诱导的细胞毒性有关.最终我们的实验数据证明,群体感应信号分子3-oxo-C12-HSL在铜绿假单胞菌感染的致病机理中扮演着重要的角色.
For many microorganisms, including Pseudomonas aeruginosa, the population sensing system is an important regulator of bacterial expression virulence factors Las and Rhl are the two major components of population sensing Las and Rhl by self-inducing agent N (3-oxo-C12-HSL) and N-butyryl-L-homoserine lactone (C4-HSL). Recent advances have shown that population 3-oxo-C12-HSL induces the apoptosis and phagocytosis of murine macrophages (RAW264.7) .This experiment demonstrated that 3-oxo-C12-HSL can regulate the host immune system The synthesized 3-oxo-C12-HSL was added to RAW264.7 cell culture medium and cell viability was found in a concentration dependent manner (6.25 to 100 μmol / L) of 3-oxo-C12-HSL and in culture time h). Similarly, we observed the cytotoxic activity of 3-oxo-C12-HSL and the morphological changes of cells treated with 3-oxo-C12-HSL showed that 3-oxo- C12-HSL-treated cells accelerated apoptosis as evidenced by several other criteria (caspases 3, 8 and 9, mitochondrial membrane potential and phosphatidylserine expression) 3-oxo-C12-HSL significantly reduced the phagocytosis of RAW264.7 cells (P <0.05), while high concentration of 3-oxo-C12-HSL decreased the ratio of RAW264.7 cells The data indicate that 3-oxo-C12-HSL can specifically promote the induction of apoptosis and the decrease of phagocytosis of RAW264.7 cells.This may be related to the 3- oxo-C12-HSL.Finally, our experimental data demonstrated that the population-sensing signal molecule 3-oxo-C12-HSL plays an important role in the pathogenesis of Pseudomonas aeruginosa infection.