牙龈卟啉单胞菌FimA促进ESCC细胞MHC-I的降解与免疫抑制

Virulence factors FimA of Porphyromonas Gingivalis Inhibits the Immunity by Triggering MHC-I Degradation

目的探讨牙龈卟啉单胞菌(Porphyromonas gingivalis,Pg)感染食管鳞状细胞癌细胞后对主要组织相容性一类分子(MHC-I)的影响及其免疫调控机制。方法Western blot检测Pg感染KYSE-150细胞后主要毒力因子鞭毛蛋白(fimbriae,FimA)及MHC-I的表达水平,免疫共沉淀(Co-immunoprecipitation,Co-IP)法探索FimA和MHC-I之间的相互作用,共聚焦检测KYSE150细胞转染LC3双荧光慢病毒后的荧光变化,western blot检测Pg感染KYSE150后LC3B-Ⅱ的表达量,流式细胞术检测感染Pg的KYSE150与外周血单个核细胞(peripheral blood mononuclear cells,PBMC)共培养后PMBC表达MKi67的情况。结果Western blot显示Pg感染KYSE150细胞后FimA的表达增多而MHC-I的表达减少。Co-IP显示FimA与MHC-I蛋白可直接相互作用,共聚焦显微镜显示Pg感染KYSE150后荧光强度增强,流式细胞术显示Pg感染的KYSE150细胞与PBMC细胞共培养后能显著降低PBMC中Gzmb和Mki67的表达(均P<0.001)。结论FimA可能通过自噬途径促进MHC-1的降解、抑制T细胞免疫应答,参与ESCC的免疫抑制和肿瘤进展。

Objective To investigate the impact and regulatory mechanisms of Pg infection on MHC-I molecules in esophageal squamous cell carcinoma(ESCC)cells.Methods Western blot was employed to assess the expression levels of the major virulence factor fimbriae(FimA)and MHC-I after Pg infection of KYSE-150 cells.Immunoprecipitation(Co-immunoprecipitation,Co-IP)was used to explore the interaction between FimA and MHC-I.Confocal microscopy was utilized to monitor changes in fluorescence following LC3 dual-fluorescence lentivirus transduction in KYSE150 cells.Western blot was conducted to measure the expression of LC3B-Ⅱafter Pg infection in KYSE150 cells.Flow cytometry was employed to evaluate Ki67 expression in Peripheral Blood Mononuclear Cells(PBMCs)following co-culture with Pg-infected KYSE150 cells.Results Western blot revealed increased expression of FimA and decreased expression of MHC-I after Pg infection of KYSE150 cells.Co-IP indicated a direct interaction between FimA and MHC-I proteins.Confocal microscopy demonstrated enhanced fluorescence intensity after Pg infection of KYSE150 cells.Flow cytometry showed significant reduction of Gzmb and Mki67 expression in PBMCs co-cultured with Pg-infected KYSE150 cells(both P<0.001).Conclusion The Pg virulence factor FimA may downregulate MHC-I expression through the autophagy pathway and suppress T-cell immune responses,thereby promoting the formation of an inhibitory immune microenvironment in ESCC and facilitating tumor progression.