D-环丝氨酸抑制铜绿假单胞菌群体感应活性研究

摘要：目的 以铜绿假单胞菌模式菌株PAO1为研究对象，研究抗结核药物D-环丝氨酸通过靶向抑制病原菌群体感应 (quorum-sensing，QS)系统实现抑制病原菌毒力发挥的新应用潜力。方法 用不同浓度的D-环丝氨酸处理铜绿假单胞菌，通过 系列表型实验结合荧光定量PCR以评估D-环丝氨酸对群体感应所调节的毒力因子和相应基因表达的影响，并利用秀丽隐杆线虫 感染模型评估D-环丝氨酸对铜绿假单胞菌毒力抑制的体内活性。结果 D-环丝氨酸表现出良好的铜绿假单胞菌生物膜、绿脓菌 素以及蛋白水解酶抑制活性，显著抑制了QS系统调控基因和下游功能基因的表达，并且可以显著提高秀丽隐杆线虫在铜绿假单 胞菌感染过程的存活率。结论 D-环丝氨酸可以有效抑制铜绿假单胞菌群体感应系统，有望开发成功的抗生素替代药物。

Inhibition activity of D-cycloserine on quorum-sensing system of Pseudomonas aeruginosa

Abstract Objective Using Pseudomonas aeruginosa model strain PAO1 as the model to evaluate the effect of the classic anti-tuberculosis drug D-cycloserine on inhibition of bacterial virulence by targeting the quorumsensing (QS) system. Methods Virulence phenotyping experiments combined with fluorescence quantitative PCR were used to investigate the effect of D-cycloserine on the expression of virulence factors and QS-encoding genes regulated by P. aeruginosa QS system. Caenorhabditis elegans infection model was then used to evaluate the protection by D-cycloserine against the challenge of P. aeruginosa. Results D-cycloserine could significantly inhibit the production of biofilm, pyocyanin, and extracellular proteases of P. aeruginosa. D-cycloserine also reduced the expression levels of a series of QS-controlled genes. Furthermore, the application of D-cycloserine protected C. elegans from P. aeruginosa challenge, in both of the fast killing and the slow killing assays. Conclusion This study reveals that D-cycloserine can effectively inhibit the QS system and virulent factors of P. aeruginosa which makes D-cycloserine a potential anti-virulent drug as an antibiotic substitute.