3-O-C_(12)-HSL通过PPARγ抑制Mo-DCs表达IL-6

3-O-C_(12)-HSL inhibits IL-6 expression through PPARγ in monocytes derived-dendritic cells

目的研究铜绿假单胞菌分泌的N-3-氧代十二烷酰-L-同型丝氨酸内酯(N-3-oxododecanoyl-L-homoserine lactone,3-O-C12-HSL)是否通过过氧化物酶增殖物激活受体γ(peroxisome proliferater-activated receptorγ,PPARγ)调节单核细胞来源的树突细胞(monocytes derived-dendritic cells,Mo-DCs)表达白细胞介素6(interleukin-6,IL-6)。方法 PPARγ配体筛选实验体外检测3-O-C12-HSL是否与PPARγ结合。免疫磁珠法分选人CD14+单核细胞,人白细胞介素4(human Interleukin 4,h IL-4)及人粒单核细胞集落刺激因子(human granulocyte monocyte colony stimulating factor,h GM-CSF)诱导分化为Mo-DCs,不同浓度的3-O-C12-HSL处理Mo-DCs;PPARγ拮抗剂GW9662处理Mo-DCs后,3-O-C12-HSL处理Mo-DCs,电化学发光法检测Mo-DCs培养上清IL-6浓度。结果配体筛选实验显示3-O-C12-HSL>4.60μmol/L时可竞争性结合PPARγ配体结合区。3-O-C12-HSL下调脂多糖(lipopolysaccharide,LPS)诱导的Mo-DCs表达IL-6水平(P<0.05),PPARγ特异性拮抗剂GW9662能部分逆转3-O-C12-HSL介导的IL-6表达下调(P<0.05)。结论 3-O-C12-HSL可与PPARγ相结合,并通过PPARγ调节Mo-DCs分泌表达IL-6。

Objective We investigate whether N-3-oxododecanoyl-L-homoserine lactone（3-O-C12-HSL）, a signal molecule secreted by Pseudomonas aeruginosa, mediates peroxisome proliferater-activated receptor γ（PPARγ） to affect the secretion of IL-6 in monocyte derived dendritic cells（Mo-DCs）.Methods PPARγ ligand screening assay was used to determine whether 3-O-C12-HSL was a potential ligand to PPARγ in vitro. After human CD14^＋ monocytes were separated by immunomagnetic beads, the cells were cultured with h IL-4 and h GM-CSF to induce Mo-DCs. Then electrochemiluminescence assay was used to determine the concentrations of IL- 6 in the supernatants of the Mo-DCs treated with different doses of 3-O-C12-HSL, and the concentrations were detected again in combination with GW9662, PPARγ inhibitor. Results The ligand screening assay showed that 4.60 μmol/L, 3- O- C12- HSL could bind to the PPARγ ligand binding domain competitively. The molecule significantly inhibited the secretion of IL- 6 by Mo-DCs induced by lipopolysaccharide（LPS）.What＇s more, PPARγ inhibitor GW9662 could partially reverse the molecule mediated down-regulation of IL-6. Conclusion3-O-C12-HSL can bind to PPARγ, and then inhibit the secretion of IL-6 by Mo-DCs through it.