MiR-200a Can Alleviate Renal Interstitial Fibrosis By Inhibiting Wnt/β-catenin Signaling Pathway

Background:Renal interstitial fibrosis is the final outcome of various chronic kidney disease progression to end-stage renal disease.Interstitial fibrosis is a complex pathophysiological process that involving a wide range of cellular and molecular events,a variety of cytokines and multiple signaling pathways,the main pathological features are the accumulation of extracellular matrix and activation of fibroblasts.Studies have shown that Wnt/ β-catenin signaling pathway is activated in renal disease and involved in the process of renal interstitial fibrosis,but the specific mechanism of renal interstitial fibrosis is unknown.MiRNAs are a small molecule non coding RNA,they play an important role in the process of life,they bind to mRNA’3’UTR to regulate the target gene.In the process of renal fibrosis,researches of miR-200 family are mainly focused on the transdifferentiation of renal tubular epithelial cells,but less on the Wnt/ beta-catenin signaling pathway.Our previous cell experiments and bioinformatics analysis showed that the mRNA of beta-catenin was the target gene by miR-200 a.In vivo,whether miR-200 a can play a role in the Wnt/β-catenin signaling pathway is not clear.Objective:To investigate the effects of miR-200 a on Wnt/ β-catenin signaling pathway in unilateral ureteral obstruction model,further to explore the effects of miR-200 a on renal interstitial fibrosis.Methods:Unilateral ureteral obstruction(UUO)mouse models were used,a total of 24 six weeks C57 BL / 6 male mice were randomly divided into four groups(n = 6),sham operation group,UUO group,UUO + miR-200 a group,UUO +miR-NC group.On the first day,each mice was given agomir 40 mg / kg.d(miR-200 a agonist)by tail vein injection in UUO + miR-200 a group while in the UUO +miR-NC group,each mice was given 40 mg / kg of Negative Control,for three consecutive days.After 7 days,RT-PCR,Western Blot and immunohistochemistry were used to detect mRNA and protein expression levels of Wnt4,β-catenin,Fibronectin,α-SMA.HE and Masson staining were used to detect pathological changes in kidneys.Result:1.The expression level of miR-200 a in UUO model group was significantly lower than that in sham operation group(P < 0.05).Agomir could increase the expression level of 200 a in UUO+miR-200 a group,compared with UUO group(P < 0.05).2.Compared with the Sham operation group,expression levels of Wnt4,β-catenin,Fibronectin,α-SMA mRNAs and proteins were increased in UUO group(P<0.05);compared with the sham UUO group,the expression levels of Wnt4,β-catenin,Fibronectin,α-SMA mRNAs and proteins were significantly lower in UUO+miR-200 a group(P < 0.05).3.Compared with the Sham operation group,renal tubular injury and the interstitial collagen deposition area were increased in UUO group(P<0.05);compared with the UUO group,renal tubular injury and the interstitial collagen deposition area were significantly reduced in UUO+miR-200 a group(P < 0.05).4.Compared with the Sham operation group,serum creatinine and urea nitrogen levels were increased in UUO group(P<0.05);compared with the UUO group,serum creatinine and urea nitrogen levels were significantly decreased in UUO+miR-200 a group(P<0.05).Conclusion:1.The expression level of miR-200 a was decreased in renal interstitial fibrosis;2.Wnt signaling pathway was activated in renal interstitial fibrosis;3.miR-200 a can inhibit the activated Wnt / β-catenin signaling pathway in UUO models;4.miR-200 a can alleviate renal interstitial fibrosis and relieve renal function.