MiR-143-3p expression is positively correlated with Treg-related cytokine IL-10
Negative correlation of miR-143-3p with markers of disease activity indicates the potential protective effect in RA. Due to aberrant activation of CD4+ T helper (Th) cells considered as one of the crucial causations in the initiation and perpetuation process of RA, we collected some Th-related cytokine in plasma of patients by ELISA, such as IFN-γ, IL-4, IL-10, IL-17A, which predominantly secreted by Th1, Th2, Treg, and Th17 cells, to further evaluate the role of miR-143-3p in the progression of RA. Compared with healthy controls, the levels of secreted IFN-γ and IL-17A were increased in a degree-dependent manner (Figure 2A, D). And more notably, the level of secreted IL-4 and IL-10 in plasma was significantly higher in patients with moderate RA than in HC, while expression of IL-4 and IL-10 was slightly reduced in patients with severe RA in comparison with moderate RA (Figure 2B-C), whose changing trend was similar to miR-143-3p in peripheral blood CD4+T cells. We also observed the levels of IL-4 (r=-0.3863, P=0.0159) and IL-10 (r=-0.3256, P=0.0369) were inversely correlated with the DAS28, which is consistent with the characteristics of IL-4 and IL-10 as anti-inflammatory factors in inhibiting inflammation (Figure 2E-H). Importantly, the results of further analysis showed that the expression of miR-143-3p was positively correlated IL-4 (r=0.3239, P=0.0377) and IL-10 (r=0.3443, P=0.0290). These results indicated that there was a correlation between miR-143-3p and Th2 or Treg cells. Recent bioinformatics analysis has obtained miR-143-3p may contribute to the Foxp3 signaling pathway[29,30]. Thus, we concentrated on the effect of miR-143-3p on Treg cells and conduct the further study.