Glomerular and tubulointerstitial miR-638, miR-198 and miR-146a expression in lupus nephritis

Aim: MicroRNAs (miRNAs) play important roles in the pathogenesis of autoimmune diseases. We studied the intra‐renal expression of miRNA targets that were reported to be differentially expressed in peripheral blood or urine between lupus nephritis (LN) patients and normal controls. Methods: We quantified the expression of in glomerulus and tubulointerstitium of miR‐146a, miR‐155, miR‐198 miR‐638 and miR‐663 in 42 patients with LN and 10 healthy controls. Results: As compared with controls, LN patients had lower glomerular expression of miR‐638 (P < 0.001) but higher tubulointerstitial expression of this target (P = 0.001). Both glomerular and tubulointerstitial expression of miR‐198 were higher in LN patients than controls (P < 0.001). For miR‐146a, LN patients only had higher expression in glomerulus (P = 0.005) but not in tubulointerstitium. Tubulointerstitial miR‐638 expression was significantly correlated with proteinuria (r = 0.404; P = 0.022) and disease activity score (r = 0.454; P = 0.008), while glomerular miR‐146a expressions were correlated with estimated GFR (r = 0.453; P = 0.028) and histological activity index (r = 0.494; P = 0.027). Conclusion: We found that intra‐renal expression of miR‐638, miR‐198 and miR‐146a are differentially expressed between LN patients and normal controls. Furthermore, the degree of change in glomerular miR‐146a and tubulointerstitial miR‐638 expression correlated with clinical disease severity. The results suggested that these miRNA targets may play a role in the pathogenesis of lupus nephritis.