铜绿假单胞菌3-氧十二烷酰高丝氨酸内酯信号分子对单核细胞Toll样受体2和4的影响

Expression of Toll-like receptors in human peripheral blood monocyte stimulated with N-(3-oxododecanoyl)-L-homoserine lactone from Pseudomonas aeruginosa biofilm

目的研究铜绿假单胞菌群体感应系统信号分子3-氧十二烷酰高丝氨酸内酯(3-O-C12-HSL)对人外周血单核细胞凋亡以及TLR2/4 mRNA表达的影响。方法自健康献血者血液中分离单核细胞进行体外培养,并以0、1、10、50和100μmol/L 3-O-C12-HSL作用,采用MTT法,观察不同浓度的3-O-C12-HSL分别作用对人单核细胞生长增殖的影响。用RT-PCR测定单核细胞TLR2/4 mRNA表达。结果3-O-C12-HSL刺激单核细胞12 h后TLR2/4 mRNA表达降低,且呈剂量依赖关系,TLR2/4 mRNA在100μmol/L时最为显著(0.3494±0.0979,0.3351±0.1121)。3-O-C12-HSL对单核细胞增殖有抑制作用,呈剂量依赖关系,差异有显著性(P≤0.05)。结论3-O-C12-HSL可以激发单核细胞细胞凋亡,下调Toll样受体的表达水平,从而削弱单核细胞对铜绿假单胞菌的应答能力,这可能是铜绿假单胞菌逃逸免疫清除的重要原因之一。

Objective To investigate the effect of N-（3-oxododecanoyl）-L-homosefine laetone （3-O-C12-HSL, signaling molecule of Pseudomonas aeruginosa biofilm） on the expression of toll like receptors （TLR） 2/4 mRNA and the apoptosis of monocyte. Method Human monocytes, isolated from the peripheral blood of healthy donors, were cultured with 3-O-C12-HSL in different concentration of 0,1,10,50 and 100μmol/L for 12 hours; the proliferation capacity of cells was observed by MTT. The expression of TLR2/4 mRNA was observed by reverse transcription RT-PCR. Result After 12 h treatment with 3-O-C12-HSL,TLR2/4 mRNA expression was reduced in a dose-dependent manner;the inhibition of 3-O- C12-HSL was most significant at the concentration of 100 μmol/L （0. 3494 ± 0.0979, 0. 3351 ± 0.1121 ）. The proliferation of these monecyte cells was inhibited in a dose-dependent maner. Conclusion 3-O-C12-HSL can induce the monocyte cells apoplosis, decrease the expression of TLRs, and may contribute to immune evasion of the Pseudomonas aeruginosa.