基于PERK/ATF4/CHOP信号通路探讨瑞香素对类风湿关节炎滑膜成纤维细胞的影响

Effects of daphresin on synovial fibroblasts in rheumatoid arthritis based on PERK/ATF4/CHOP signaling pathway

目的探讨瑞香素(daphnetin,DAP)对人类风湿关节炎滑膜成纤维细胞(RA-FLS)的作用及其与内质网应激(endoplasmic reticulum stress,ERS)PERK/ATF4/CHOP信号通路的关系。方法RA-FLS细胞培养,免疫荧光法检查波形蛋白(vimentin)和CD68对细胞进行鉴定;CCK-8检测(0、5、10、20、30、40、50、60、70)mg·L^(-1) DAP对RA-FLS细胞增殖活性的影响,根据增殖活性将实验分为空白组(Blank)、低剂量组(L-DAP)、中剂量组(M-DAP)、高剂量组(H-DAP)以及高剂量+抑制剂4-PBA组(H-DAP+4-PBA);ELISA检测TNF-α、IL-6水平;流式细胞术检测细胞凋亡;Transwell及划痕实验检测细胞侵袭及迁移能力,Western blot检测细胞中与内质网应激相关蛋白GRP78、PERK、p-PERK、ATF4、CHOP、Caspase-12、C-caspase-12、Bcl-2表达。结果CCK-8结果显示,与0 mg·L^(-1) DAP组比较,20~70 mg·L^(-1) DAP中各组增殖活性均差异具有显著性(P<0.05),组间比较后0、20、40、60 mg·L^(-1) DAP对应的细胞增殖率差异具有统计学意义(P<0.05),以此浓度分别作为空白、低剂量、中剂量、高剂量组以及高剂量+4-PBA实验分组依据;DAP可成浓度依耐性抑制RA-FLS细胞炎症因子IL-6、TNF-α释放,减弱细胞侵袭能力,促进细胞凋亡,上调PERK、p-PERK、ATF4、GRP78、CHOP及Caspase-12及C-caspase-12蛋白表达,降低抗凋亡蛋白Bcl-2表达水平。另一组实验证明,高剂量DAP+4-PBA可上调IL-6、TNF-α表达以及细胞侵袭,抑制细胞凋亡及ERS相关蛋白表达。结论DAP可通过激活PERK/ATF4/CHOP信号通路调节相关炎症因子分泌,抑制RA-FLS细胞增殖及侵袭,诱导细胞凋亡,有望成为治疗RA的潜在途径。

Aim To investigate the effects of DAP on human rheumatoid arthritis synovial fibroblasts(RA-FLS)and its relationship with endoplasmic reticulum stress(ERS)PERK/ATF4/CHOP signaling pathway.Methods RA-FLS cells were cultured and identified by immunofluorescence assay for Vimentin and CD68.CCK-8 detected(0,5,10,20,30,40,50,60,70)mg·L^(-1) DAP on the proliferation activity of RA-FLS cells.According to the proliferation activity,the experiment was divided into blank group(Blank),low dose group(L-DAP),medium dose group(M-DAP),high dose group(H-DAP)and high dose+specific inhibitor 4-PBA group(H-DAP+4-PBA).The levels of TNF-αand IL-6 were detected by ELISA.Cell apoptosis was detected by flow cytometry.The invasion and migration of cells were detected by Transwell and scratches assays,and the expressions of endoplasmic reticulum stress-related proteins GRP78,PERK,P-PERK,ATF4,CHOP,Caspase-12,C-Caspase-12 and Bcl-2 were assessed by Western blot.Results CCK-8 results showed that compared with 0 mg·L^(-1) DAP group,the proliferation activity of each group in 20-70 mg·L^(-1) DAP group was significantly different(P<0.05),and the proliferation rate corresponding to 0,20,40 and 60 mg·L^(-1) DAP group was significantly different(P<0.05).This concentration was used as the basis for blank,low-dose,medium-dose,high-dose groups and high-dose+4-PBA experimental grouping.DAP could inhibit the release of inflammatory cytokines IL-6 and TNF-αfrom RA-FLS cells in concentration,reduce the invasion ability of cells,promote apoptosis,upregulate the expression of PERK,P-PERK,ATF4,GRP78,CHOP,Caspase-12,C-caspase-12 proteins and decrease the expression level of anti-apoptotic protein Bcl-2.Another set of experiments demonstrated that high dose DAP+4-PBA could up-regulate the expression of IL-6 and TNF-α,as well as the invasion of cells,and inhibit the expression of apoptosis and ERs-related proteins.Conclusions Daphresin regulates the secretion of inflammatory factors by activating the PERK/ATF4/CHOP signaling pathway,inhibits the proliferation and invasion of RA-FLS cells,and induces apoptosis,which is expected to be a potential therapeutic pathway for RA.