Mycophenolic Acid Upregulates MiR-142-3P/5P And Mir-146a In Lupus CD4~+T Cells And Its Mechanisms

Objective:Mycophenolic acid (MPA), an active metabolite of mycophenolate mofetil (MMF), is a noncompetitive inhibitor of inosine monophosphate dehydrogenase (IMPDH), and now widely used for the treatment of SLE. Dys-regulated expression of miRNA has been reported to be involved in the pathogenesis of SLE. However, it is unknown whether altering miRNA expression in SLE is one of therapeutic effects of MPA. Thus, this study aimed to investigate the effect of MPA on microRNAs expression in lupus CD4+T cells and its underlying mechanisms.Methods:T cells were isolated by positive selection using CD4beads.Activated normal CD4+T cells from healthy donors were exposed to MPA at concentration of1,5,10μm/1and incubated for48hours Protein level of CD40Ligand (CD40L) and cell apoptosis were measured by flow cytometric analysis. Lupus CD4+T cells were exposed to1μm/1MPA and then subjeceted to microRNA array analysis. Differentially expressed miRNAs were validated by quantitative real-time PCR. Histone modification status of miR-142and miR-146a were assayed by ChIP-quantitative PCRResults:Analysis of the microarray data identified101miRNAs significantly upregulated and77miRNAs significantly downregulated in MPA-treated lupus CD4+T cells. MiR-142-3p/5p and miR-146a expression were significantly increased in MPA-treated lupus CD4+T cells compared to untreated control(p<0.05;p<0.05respectively) Furthermore, We found that MPA-treated CD4+T cells from patients with SLE showed enriched levels of H4acetylation in the putative miRNA-142regulatory region and enriched levels of H3acetylation in the putative miRNA-146a regulatory region compared with untreated cells(p<0.05;p<0.05respectively).However, H3acetylation, H3K4tri-methylation (H3K4me3),H3K9tri-methylation(H3K9me3) levels in the putative miRNA-142regulatory region and H4acetylation, H3K4me3, H3K9me3levels in the putative miRNA-146a regulatory region showed no significant difference between MPA-treated lupus CD4+T cells and untreated cells.Conclusion:Data from the present study demonstrates that MPA upregulates expression of miR-142and miR-146a through promoter histone modifications.