大肠杆菌EscI蛋白C-末端多肽诱导巨噬细胞炎性体应答

Inflammasome responses in macrophages induced by C-terminal peptides of Escherichia coli EscI protein

摘要:

摘要:【目的】分析E.coli的EscI蛋白C-末端多肽诱导巨噬细胞NLRC4炎性体应答情况。【方法】以含有E.coli的EscI蛋白C-末端氨基酸序列的多肽为材料，通过体外导入小鼠腹腔巨噬细胞，分析细胞的应答情况。【结果】利用脂多糖预先刺激后，含有EscI蛋白C-末端15个氨基酸的多肽能够明显地激活细胞内NLRC4炎性体应答，细胞内半胱氨酸天冬氨酸蛋白酶1 被激活，细胞发生pyroptosis，细胞培养上清中IL-1β和IL-18的含量增加(P＜0.05)。通过优化刺激条件发现，以多肽/脂质体为70 μg/μL的比例导入细胞并孵育4 h时，IL-1β的分泌量最高。【结论】含有E.coli的EscI蛋白C-末端15个氨基酸的多肽能够明显地诱导巨噬细胞NLRC4炎性体应答。

Abstract:

Abstract:［Objective］To analyze NLRC4 inflammasome responses in macrophages induced by C-terminal of Escherichia coli EscI protein． ［Methods］ NLRC4 inflammasome responses in mouse peritoneal macrophages were analyzed after delivery of the peptides containing C-terminal amino acid sequences of E.coli EscI protein in vitro.［Results］ The peptides containing C-terminal 15 amino acids of EscI protein could significantly activate NLRC4 inflammasome responses in macrophages pre-stimulated with lipopolysaccharide． Intracellular caspase-1 was activated and pyroptotic dead cells were found after peptides delivery． The contents of cytokines，IL-1β and IL-18，in supernatants were elevated significantly compared with that of the control (P＜0.05)．Besides，through comparison of IL-1β contents under different stimulation conditions，4 h incubation after peptides delivery (peptides: lipofectamine 2000=70 μg/μL) could obviously promote the secretion of IL-1β． ［Conclusion］ Peptides containing C-terminal 15 amino acids of E.coli EscI protein can significantly induce NLRC4 inflammasome activation in macrophages.