抑制GRK2异常转膜控制JAK1-STAT1信号转导减少CIA小鼠树突状细胞的成熟

Inhibition of abnormal GRK2 transmembrane transfer to reduce maturation of dendritic cells in CIA mice by regulating JAK1-STAT1 signaling pathway

目的G蛋白偶联受体激酶2(G protein-coupled receptor kinase 2,GRK2)异常活化和JAK1-STAT1信号转导异常参与类风湿关节炎(rheumatoid arthritis,RA)的免疫异常反应,但两者关系不清。该文研究了GRK2对胶原性关节炎(collagen-induced arthritis,CIA)小鼠树突状细胞(dendritic cells,DCs)JAK1-STAT1信号通路的作用和机制,为揭示RA的新机制提供依据。方法建立CIA模型,流式细胞术检测DCs共刺激分子水平,ELISA检测小鼠血浆细胞因子水平,免疫组化法检测脾脏组织中p-JAK1、p-STAT1、GRK2的表达。体外用骨髓细胞诱导成DCs,IFN-α和PGE2刺激48 h。流式细胞术检测DCs共刺激分子水平和吞噬能力,ELISA检测细胞上清中细胞因子水平。CO-IP法检测DCs中GRK2和JAK1共定位。Western blot法检测JAK1、STAT1、胞膜GRK2表达。成像流式细胞术检测p-STAT1入核率。结果CIA小鼠中DCs共刺激分子水平升高,脾脏中GRK2与p-JAK1、p-STAT1的表达呈正相关,且CIA组脾脏中GRK2与JAK1共定位明显下降。体外实验表明,GRK2抑制剂降低DCs共刺激分子表达、IL-6和TNF-α水平,JAK1、STAT1表达、GRK2胞膜表达、p-STAT1入核,增加DCs吞噬功能及GRK2与JAK1的共定位。结论DCs中GRK2转膜异常,介导了DCs的成熟和JAK1-STAT1信号通路活化,抑制GRK2转膜可恢复其对DCs的JAK1-STAT1信号转导的控制,减少DCs的成熟,在改善小鼠CIA中发挥重要作用。

Aim To reveal the role of the abnormal activation of G protein-coupled receptor kinase 2(GRK2)and abnormal signal transduction of JAK1-STAT1 in the abnormal immune response of rheumatoid arthritis(RA)by exploring the effects of GRK2 on the JAK1-STAT1 signaling pathway in dendritic cells(DCs)of collagen-induced arthritis(CIA)mice and the undelying mechanisms,so as to provide a basis for revealing the new mechanism of RA.Methods The CIA model was established,and the co-stimulatory molecular level of DCs was detected by flow cytometry,the cytokine levels of plasma in mice were detected by ELISA,and the expression of p-JAK1,p-STAT1 and GRK2 in spleen tissues was detected by immunohistochemistry.Bone marrow cells were induced into DCs in vitro and stimulated with IFN-αand PGE2 for 48 h.Flow cytometry was used to detect the level of co-stimulatory molecules and phagocytosis of DCs,and ELISA to detect the level of cytokines in cell supernatant.CO-IP was employed to detect the co-localization of GRK2 and JAK1 in DCs.Western blotting was used to detect the expression of JAK1-STAT1 and the cell membrane expression of GRK2.Imaging flow cytometry was applied to detect the nucleation rate of p-STAT1.Results In vivo the level of co-stimulatory molecules of dendritic cells of CIA mouse increased,and the expression of GRK2 and p-JAK1,p-STAT1 in spleen was positively correlated.The co-localization of GRK2 and JAK1 in spleen of the CIA group decreased significantly.In vitro GRK2 inhibitors reduced the level of costimulatory molecules,cytokines IL-6 and TNF-α,the expression of JAK1 and STAT1,the expression of GRK2 in the cell membrane,and the rate of p-STAT1 nuclear translocation,and increased the Ag uptake capacity of DCs and the co-localization rate of GRK2 and JAK1.Conclusions The abnormal GRK2 transfer to the cell membrane in DCs mediates the maturation of DCs and the activation of the JAK1-STAT1 signaling pathway.Inhibition of GRK2 transfer membrane can restore its control of the JAK1-STAT1 signal transduction of DCs,reduce the maturation of DCs,and play an important role in improving mouse CIA.