Circ_LARP4 regulates high glucose-induced cell proliferation, apoptosis, and fibrosis in mouse mesangial cells.

The current study aimed to investigate the role and underlying mechanisms of circ_LARP4 in diabetic nephropathy (DN). Here, mouse mesangial cells (SV40-MES13) were cultured with 30 mM glucose to establish a DN cellular model. The qRT-PCR results indicated that circ_LARP4 expression was downregulated in the DN cellular model compared to that in the control cells. As determined by an MTT assay, circ_LARP4 overexpression via the circ_LARP4 overexpression (OE) plasmids inhibited the cell proliferation rate. As determined by an Annexin V/PI kit and flow cytometry, circ_LARP4 overexpression increased the cell apoptosis rate. As measured by Western blot, circ_LARP4 overexpression enhanced BAX expression but reduced Bcl-2 expression, also suggesting an enhancement of cell apoptosis. Moreover, regarding cell fibrosis, circ_LARP4 overexpression reduced the mRNA levels of fibrosis markers, including fibronectin, collagen I and collagen IV. Interestingly, miR-424 was found to be reduced in the DN cellular model after transfection with the circ_LARP4 OE plasmids. In addition, restoration of miR-424 expression with the miR-424 mimics reversed the negative effects of circ_LARP4 overexpression on cell proliferation and fibrosis. In conclusion, circ_LARP4 was lower in the DN cellular model than in normal cells, and circ_LARP4 overexpression resulted in decreased cell proliferation and cell fibrosis but increased cell apoptosis in the DN cellular model by sponging miR-424.

LINC00052 ameliorates acute kidney injury by sponging miR-532-3p and activating the Wnt signaling pathway.

Acute kidney injury (AKI) is a complex renal disease. Long non-coding RNAs (lncRNAs) have frequently been associated with AKI. In the present study, we aimed to investigate the molecular mechanism(s) of LINC00052 in AKI. We found that LINC00052 expression was significantly decreased in AKI patient serum. In addition, in a hypoxic AKI cell model, LINC00052 expression was strongly elevated. In an I/R-triggered AKI rat model, the expression of TNF-α, IL-6 and IL-1ß mRNA was strongly elevated. Moreover, we predicted miR-532-3p to be targeted by LINC00052 in AKI. Overexpression of LINC00052 increased hypoxia-induced inhibition of NRK-52E cell proliferation and reversed hypoxia-triggered apoptosis. Furthermore, we found that induction of TNF-α, IL-6 and IL-1ß was repressed by overexpression of LINC00052. LINC00052 decreased hypoxia-induced ROS and MDA accumulation in vitro and increased SOD activity. Decreased levels of c-myc and cyclin D1 were observed in renal tissues of AKI rats. Lastly, Wnt/ß-catenin signaling was inactivated in NRK-52E cells experiencing hypoxia, and LINC00052 upregulation reactivated Wnt/ß-catenin signaling by sponging miR-532-3p. Taken together, these results suggest that LINC00052 ameliorates AKI by sponging miR-532-3p and activating Wnt signaling.

Loss of lncRNA MIAT ameliorates proliferation and fibrosis of diabetic nephropathy through reducing E2F3 expression.

Diabetic nephropathy (DN) is a serious kidney disease resulted from diabetes. Dys-regulated proliferation and extracellular matrix (ECM) accumulation in mesangial cells contribute to DN progression. In this study, we tested expression level of MIAT in DN patients and mesangial cells treated by high glucose (HG). Up-regulation of MIAT was observed in DN. Then, functional assays displayed that silence of MIAT by siRNA significantly repressed the proliferation and cycle progression in mesangial cells induced by HG. Meanwhile, we found that collagen IV, fibronectin and TGF-ß1 protein expression was obviously triggered by HG, which could be rescued by loss of MIAT. Then, further assessment indicated that MIAT served as sponge harbouring miR-147a. Moreover, miR-147a was decreased in DN, which exhibited an antagonistic effect of MIAT on modulating mesangial cell proliferation and fibrosis. Moreover, bioinformatics analysis displayed that E2F transcription factor 3 (E2F3) could act as direct target of miR-147a. We demonstrated that E2F3 was greatly increased in DN and the direct binding association between miR-147a and E2F3 was evidenced using luciferase reporter assay. In summary, our data explored the underlying mechanism of DN pathogenesis validated that MIAT induced mesangial cell proliferation and fibrosis via sponging miR-147a and regulating E2F3.

miR-98-5p Alleviated Epithelial-to-Mesenchymal Transition and Renal Fibrosis via Targeting Hmga2 in Diabetic Nephropathy.

Recently, microRNAs have been recognized as crucial regulators of diabetic nephropathy (DN) development. Epithelial-to-mesenchymal transition (EMT) can play a significant role in tubulointerstitial fibrosis, and it is a hallmark of diabetic nephropathy progression. Nevertheless, the function of miR-98-5p in the modulation of EMT and renal fibrosis during DN remains barely investigated. Hence, identifying the mechanisms of miR-98-5p in regulating EMT and fibrosis is of huge significance. In our present research, decreased miR-98-5p was demonstrated in db/db mice and mice mesangial cells treated with the high dose of glucose. Meanwhile, activated EMT and increased fibrosis was accompanied with the decrease of miR-98-5p in vitro and in vivo. Additionally, to further find out the roles of miR-98-5p in DN development, overexpression of miR-98-5p was applied. Firstly, in vivo investigation exhibited that elevation of miR-98-5p restrained proteinuria, serum creatinine, BUN, the EMT process, and fibrosis. Furthermore, high glucose was able to promote mice mesangial cell proliferation, EMT process, and induced renal fibrosis, which could be prevented by overexpression of miR-98-5p. Moreover, high mobility group A (HMGA2) can exhibit an important role in diverse biological processes. Here, HMGA2 was investigated as a target of miR-98-5p currently. Luciferase reporter assay was conducted and the correlation of miR-98-5p and HMGA2 was validated. Moreover, it was displayed that HMGA2 was remarkably elevated in db/db mice and mice mesangial cells. Furthermore, miR-98-5p strongly depressed HMGA2 protein and mRNA levels in mice mesangial cells. Overall, these revealed miR-98-5p could suppress the EMT process and renal fibrosis through targeting HMGA2 in DN.

Long non-coding RNA MEG3 promotes fibrosis and inflammatory response in diabetic nephropathy via miR-181a/Egr-1/TLR4 axis.

Long non-coding RNAs (lncRNAs) play vital roles in diabetic nephropathy (DN). This research aimed to study the potential role and underlying molecular mechanisms of long non-coding RNA MEG3 in DN. We found that MEG3 was upregulated in DN in vivo and in vitro and could enhance cell fibrosis and inflammatory response in DN. MEG3 functioned as an endogenous sponge for miR-181a in mesangial cells (MCs) via direct targeting and in an Ago2-dependent manner. MiR-181a inhibition promoted MC fibrosis and inflammatory response. In addition, Egr-1 was confirmed as a target gene of miR-181a. Further investigations verified that MEG3 promotes fibrosis and inflammatory response via the miR-181a/Egr-1/TLR4 axis in vitro and in vivo. These results provide new insights into the regulation between MEG3 and the miR-181a/Egr-1/TLR4 signaling pathway during DN progression.

MicroRNA-503 contributes to podocyte injury via targeting E2F3 in diabetic nephropathy.

Diabetic nephropathy (DN) is serious diabetic complication with capillary injury. Podocyte injury exerts a crucial effect on DN pathogenesis. MicroRNA-503 (miR-503) has been reported in various diseases including DN. Here, we investigated the detailed mechanism of miR-503 in the podocyte injury of DN. The functional role of miR-503 was investigated in cultured podocytes and diabetic rats. Podocyte injury was evaluated by migration and apoptosis experiments in podocytes and we observed that high glucose elevated miR-503 in a time and dose-dependent manner. Meanwhile, E2F transcription factor 3 (E2F3), as a crucial regulator in multiple diseases, was predicted as a potential target of miR-503 here. It was shown that E2F3 was greatly decreased in podocytes incubated with high glucose and miR-503 modulated its expression negatively. In addition, downregulation of E2F3 contributed to podocyte injury, which was reversed by miR-503 inhibitors in vitro. Furthermore, we proved that increase of miR-503 resulted in an unfavorable renal function in diabetic rats via targeting E2F3. These revealed for the first time that the overexpression of miR-503 promoted podocyte injury via targeting E2F3 in diabetic nephropathy and miR-503/E2F3 axis might represent a pathological mechanism of diabetic nephropathy progression.