AB0131 THE CORRELATION OF EXPRESSION OF DIFFERENTIAL DRUG-RESISTANT PROTEINS AND INFLAMMATORY CYTOKINES IN COLLAGEN INDUCED ARTHRITIS MODEL
Authors: Jie Liang, Xiangcong Zhao, Ning Yan, Fangyuan Hu, LI Xiaofeng, Caihong Wang
Journal: Annals of the Rheumatic Diseases (2019)

<h3>Background</h3> Rheumatoid arthritis (RA) is a systemic autoimmune disease. The most characteristic patho-logical changes are chronic synovitis. At present, the combination of traditional disease-difying anti-rheumatic drugs (DMARDs) and biological agents DMARDs has improved the therapeutic effect of RA, but some RA patients still have poor response due to Multidrug resistance (MDR) phenomenon. The main mechanism of MDR is related to the ATP-binding cassette (ABC) transporter superfamily members, which increases drug efflux and reduces intracellular drug concentration. We will study how cytokines regulate the expression of ABC transporters. <h3>Objectives</h3> By comparing the differential expression of ABC transporter family resistance-related proteins P-gp, BCRP, MRP1 and inflammatory cytokines IL-1β, IL-2, IL-6, IL-10, TNF-α and IL-17 in CIA model mice, to investigate the correlation between Inflammatory cytokines and drug-resistant proteins. <h3>Methods</h3> Fourteen DBA1 mice were successfully induced by collagen and Freund's Adjuvant. According to the scores of synovial pathology, the CIA group was divided into mild, moderate-to-severe groups, another four mice were selected as control. The mRNA expressions of P-gp, BCRP, MRP1 in splenic lymphocyte cells were measured by RT-PCR. The concentrations of IL-1β, IL-2, IL-6, IL-10, TNF-α, IL-17 in serum were detected by Cytometric Bead Array(CBA). Further analyze the correlation between different inflammatory cytokines and these proteins, then study one of the proteins which is most related with cytokines by immunohistochemical (IHC) in synovium. Two independent samples were analyzed by the Mann-Whitney U test. Non-parametric Kruskal- Wallis H test was performed on multiple independent samples. The correlation between variables was used by Spearman correlation analysis. <h3>Results</h3> Compared with the normal controls, The level of IL-6 and TNF-α in the serum of mild CIA group, moderate-severe CIA group were significantly increased (Z<sub>1</sub>=14.383, P<sub>1</sub>&lt;0.05, Z<sub>2</sub>=8.375, P<sub>2</sub>&lt;0.05). Compared with the mild CIA group, the level of IL-6 in serum were significantly increased in the moderate-to-severe CIA group (P&lt;0.05),but there was no distinct difference in the TNF-α level(P&gt;0.05). In the spleen lymphocytes, there was no significant difference in the the mRNA expression level of P-gp and BCRP among the groups, but the mRNA expression level of MRP1 were significantly increased (P&lt;0.05). Compared with the mild CIA group, the MRP1 mRNA in the moderate-to-severe CIA group was higher, there was significant difference(Z=12.634, P&lt;0.05). There was a correlation between mRNA expression of MRP1 and P-gp(r=0.635, P=0.015). The mRNA expression of MRP1 was positively correlated with IL-6 level (<i> r</i>=0.711, P=0.004). The expression of MRP1 in normal group, low-level IL-6 group and high-level IL-6 group were respectively as follows::1.08(0.65,1.30), 1.40(1.13,2.07), 1.90(1.68,2.17). Compared with the controls, the cytoplasm/membrane of the knee and ankle joint synovial tissue in the CIA group was yellowish-brown, which proved that MRP1 expression was positive. <h3>Conclusion</h3> In the CIA arthritis model, synovial tissue lesion is not only related to inflammatory cytokines, but also related to MRP1 expression in the ABC transport resistance protein family, and it is proved that IL-6 is highly correlated to MRP1. <h3>Reference</h3> [1] Chen Z, Shi T, Zhang L, et al. Mammalian drug efflux transporters of the ATP binding cassette (ABC) family in multidrug resistance: A review of the past decade[J].Cancer Letters, 2016, 370(1):153-164. DOI: 10.1016/j.canlet.2015.10. <h3>Acknowledgement</h3> The National Natural Science Fund(81471618); Shanxi Provincial Health Department research project (201201072);Shanxi Provincial Key Research and Development Program (Social Development Field) Project (201803D31119) <h3>Disclosure of Interests</h3> None declared