The Signal Transduction Pathway Of Regulation Of P-gp Expression Mediated By IL-17 In Peripheral Blood Lymphocytes Of Patients With Rheumatoid Arthritis

Background:Rheumatoid arthritis(RA)is an autoimmune disease,characterized by destructive arthritis.There are 30%-50% of RA patients,called refractory RA(RRA),who have treated with 2 or more than 2 kinds of disease-modifying anti-rheumatic drugs(DMARDs)for more than half a year,while their disease activities were recurrent,bone and joint destruction also showed a progressive trend.RRA may be associated with the production of multiple drug resistance(MDR)in DMARDs.ATP-binding cassette(ABC)transporter mediated drug delivery is the most essential mechanism of MDR production,such as P-glycoprotein(P-gp),which is studied more commonly.Previous studies showed that IL-17 can upregulate the expression and function of P-gp in peripheral blood lymphocytes in RA patients,showing a time-dependent and dose-dependent manner,which suggests that IL-17 is involved in the regulation of P-gp expression.The specific mechanism of regulation of P-gp expression mediated by IL-17 is not clear.Based on our previous studies,this research will research whether the upregulation of P-gp expression induced by IL-17 is related to TAK1-NF-?B or ERK1/2-C/EBP? pathway,and clarify the precise mechanism of P-gp upregulation mediated by IL-17 in RA.Objective:To clarify the specific signal transduction pathway of upregulation of P-gp expression mediated by IL-17,and to explore the factors influencing the baseline mRNA level of P-gp in untreated RA patients.Method:1.Mixed lymphocyte reaction of RA was established,and IL-17 A,IL-17A+(5Z)-7-Oxozeaenol(TAK1 inhibitor),IL-17 A +PD98059(ERKl/2 inhibitor)were added.The P-gp mRNA expression level was detected by RT-PCR after 24 hours.Meanwhile,P-gp function was tested by Rhodamine 123(Rh123).2.The mRNA expression levels of p-gp were detected by RT-PCR,the serum IL-17 A concentration,ESR and DAS28 were measured,and the correlation between the mRNA expression level of p-gp and IL-17 A concentration,as well as ESR,DAS28 was analysised.Result:1.The mRNA expression levels of P-gp in mixed lymphocyte reaction of each RA group were detected by RT-PCR.Compared with the control group,the mRNA level in IL-17 A group was significantly strengthened(P<0.05).Compared with IL-17 A group,the mRNA level of P-gp was decreased in IL-17A+PD98059 and IL-17A+(5Z)-7-Oxozeaenol group,the decrease in the latter group was significant(P<0.05).2.The function of P-gp in mixed lymphocyte reaction of each RA group was detected by Rh123 experiment.Compared with the control group,the function of P-gp in IL-17 A group was significantly strengthened(P<0.05).Compared with IL-17 A group,the function of P-gp was decreased in IL-17A+PD98059 and IL-17+(5Z)-7-Oxozeaenol group,the decrease in the latter group was significant(P<0.05);3.In vivo,the correlation between serum IL-17 A concentration,as well as ESR,DAS28 is not significant,which implied that the mRNA expression level of P-gp is in the same baseline among untreated RA patients.Conclusion:Inflammatory cytokines IL-17 A can upregulate the mRNA expression level and drug delivery function of P-gp in RA patients through TAK1-NF-?B pathway,contributing to RA drug resistance.In untreated RA patients,their mRNA level of P-gp is at the same baseline level.Therefore,controlling the influencing factors and reversing the expression of p-gp by early intervention may be a new target for improving the therapeutic reactivity of DMARDs in the long term.