Effect Of AhR On Abnormal Activation Of B Cells And Th17/Treg Imbalance In Systemic Lupus Erythematosus

Objective: To detect the expression level of aryl hydrocarbon receptor(AhR)and Mammalian sterile-20-like(MST1)in Systemic lupus erythematosus(SLE),The level of B cells,T helper cell 17(Th17)and regulatory T cells(Treg)were analyzed.Moreover,the influence mechanism of AhR on abnormal activation of B cells and Th17/Treg imbalance in SLE was discussed,which provided a theoretical basis for the treatment and mechanism research of systemic lupus erythematosus.Methods: 30 SLE patients diagnosed in the First Hospital of Lanzhou University and12 healthy controls were enrolled,which the relevant clinical basic data and laboratory test indexes were reviewed and peripheral blood was collected.According to the SLE disease activity index 2000(SLEDAI-2K)scoring standard,the disease activity of SLE patients was evaluated.The expression of AhR in B cells,Th17 cells and Treg cells were analyzed by flow cytometry.The expression levels of AhR and MST1 proteins in peripheral blood lymphocytes of patients and healthy controls were detected by Western-blot.At the same time,female C57BL/6J mice(n=6)were defined as healthy subject group,and female MRL/lpr mice(n=18)were divided into three groups: Model group,Vehicle group and FICZ group.The establishment of mouse model the mouse model and the degree of disease inflammation were identified by observing the pathological section of the kidney,the length,weight and index of the spleen.The expression of Th17 cells and Treg cells were analyzed in mice by flow cytometry.The expression levels of AhR and Mst1 proteins in spleen of mice were detected by western blot.Real-time PCR(q RT-PCR)was used to detect the expression level of cytokines in spleen tissue.Results: 1.The expression levels of B lymphocytes(P < 0.05)and AhR in B cells(P <0.0001)of SLE patients were significantly higher than those of healthy controls;2.The expression level of AhR in B cells of SLE patients is negatively correlated with the levels of hemoglobin(r =-0.3994,P =0.0390),C3(r =-0.5126,P = 0.0063)and C4(r=-0.4036,P = 0.0270),but positively correlated with SLEDAI-2K(r = 0.5750,P =0.0051),ESR(r = 0.6343,P = 0.0003),CRP(r = 0.5285,P = 0.0032)and lymphocyte counts(r = 0.4980,P = 0.0080);3.The area under ROC curve of AhR in B cells was0.815,and its best cutoff level was 3.05%.Its sensitivity and specificity in predicting SLE with renal damage were 83.3% and 70.0%;4.Compared with the healthy control group,Th17 cells in peripheral blood of SLE patients was significantly increased(P <0.01),and there was no significant difference in Treg cells,but Th17/Treg was significantly increased(P < 0.01),additionally,the SLEDAI-2K were positively correlated with Th17 cells(r = 0.5750,P = 0.0051)and Th17/Treg(r = 0.4421,P =0.0448);5.The protein expression levels of AhR and MST1 in peripheral blood lymphocytes of SLE patients were significantly increased(P < 0.05,P < 0.01);6.Compared with C57BL/6J,MRL/lpr mice had obvious lupus-like changes,and Th17 cells was significantly increased(P < 0.01),Treg cells was significantly decreased(P <0.01),and Th17/Treg was significantly increased(P < 0.01).In addition,the protein expression levels of AhR and Mst1 in MRL/lpr mice were increased,which was statistically significant(P < 0.05);7.Compared with Vehicle group,Th17 cells was significantly increased(P < 0.01),Treg cells was significantly decreased(P < 0.001),Th17/Treg was significantly increased(P < 0.001),Moreover,AhR in Th17 cells(P <0.01)and AhR in Treg cells(P < 0.05)were increased significantly in the spleen in FICZ group;8.Compared with Vehicle group,the protein expression levels of AhR and MST1 were increased(P < 0.05)in spleen tissue in FICZ group;9.Compared with Vehicle group,the m RNA expression of pro-inflammatory factors IL-2(P < 0.05),IL-4(P < 0.05)and TNF-α(P < 0.001)increased,while the m RNA expression of antiinflammatory factor IL-10 decreased(P < 0.01)in spleen tissue,which aggravated inflammation in FICZ group.Conclusion: 1.The expression level of AhR in B cells of SLE patients is related to SLE disease activity,which may be a potential index to predict SLE complicated with renal damage;2.Th17/Treg imbalance is correlated with disease activity in SLE;3.AhR may induce Th17/Treg imbalance through MST1,and then participate in the progression of SLE.