Diabetic nephropathy (DN) remains one of the severe complications associated with diabetes mellitus. It is worthwhile to uncover the underlying mechanisms of clinical benefits of human urine‐derived stem cells (hUSCs) in the treatment of DN. At present, the clinical benefits associated with hUSCs in the treatment of DN remains unclear. Hence, our study aims to investigate protective effect of hUSC exosome along with microRNA‐16‐5p (miR‐16‐5p) on podocytes in DN via vascular endothelial growth factor A (VEGFA). Initially, miR‐16‐5p was predicated to target VEGFA based on data retrieved from several bioinformatics databases. Notably, dual‐luciferase report gene assay provided further verification confirming the prediction. Moreover, our results demonstrated that high glucose (HG) stimulation could inhibit miR‐16‐5p and promote VEGFA in human podocytes (HPDCs). miR‐16‐5p in hUSCs was transferred through the exosome pathway to HG‐treated HPDCs. The viability and apoptosis rate of podocytes after HG treatment together with expression of the related factors were subsequently determined. The results indicated that miR‐16‐5p secreted by hUSCs could improve podocyte injury induced by HG. In addition, VEGA silencing could also ameliorate HG‐induced podocyte injury. Finally, hUSC exosomes containing overexpressed miR‐16‐5p were injected into diabetic rats via tail vein, followed by qualification of miR‐16‐5p and observation on the changes of podocytes, which revealed that overexpressed miR‐16‐5p in hUSCs conferred protective effects on HPDCs in diabetic rats. Taken together, the present study revealed that overexpressed miR‐16‐5p in hUSC exosomes could protect HPDCs induced by HG and suppress VEGFA expression and podocytic apoptosis, providing fresh insights for novel treatment of DN.

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BackgroundResistin-like molecule beta (RELM-β) has been reported to be associated with diabetic nephropathy (DN). However, the role of RELM-β in DN is poorly understood. This study was conducted to delineate the underlying mechanisms of action and to investigate the role of RELM-β in the primitive development of DN via MAPK signaling pathways.Material/MethodsLentivirus-mediated vectors and RNAi technology were used to establish the model of RELM-β up-regulated and down-regulated expression in human mesangial cells (HMCs). The proliferation of HMCs was detected through CCK-8 method. The cell cycle and cell proliferation of HMCs was detected through flow cytometry. The MAPKs pathway protein activity was detected through Western blotting.ResultsThe HMCs with up-regulated and down-regulated expression of RELM-β increased or decreased significantly at 2–3 days. The HMCs with high glucose intervention reversed the proliferation inhibition. The HMCs with exogenous glucose or RELM-β protein intervention partially reversed the cell cycle inhibition. Among the MAPKs pathway, the phosphorylation activity of p38MAPK and JNK increased or decreased and ERK1/2 did not change in the overexpression or inhibition of RELM-β. The p38 MAPK pathway inhibitor SB202190 significantly inhibited the proliferation of HMCs caused by overexpression of RELM-β. Up-regulated expression of RELM-β induced the phosphorylation of p38 MAPK, JNK in HMCs and promoted HMCs proliferation and participated in early DN through the MAPKs pathway.ConclusionsThe results provide evidence that RELM-β is a potential molecular target for the treatment of DN.

The present study aimed to explore the roles of microRNA-21 (miR‑21) and the transforming growth factor-β (TGF-β)/Smad signaling pathway in the development of peritoneal fibrosis (PF). First, dialysis effluents from 30 patients with PF were collected, and after the establishment of a mouse model of PF, hematoxylin and eosin (H&E) and Masson's staining were used to observe peritoneal tissues, inflammatory cells and blood vessels. High glucose was used to stimulate human peritoneal mesothelial cell lines and these stimulated cells were then transfected with miR‑21 inhibitor. Immunofluorescence microscopy was applied for the observation of the transfected cells. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was used to detect the expression of miR‑21, and RT-qPCR and western blot analysis were used to detect the mRNA and protein expression of Zonula occludens-1 (ZO-1), TGF-β, Smad, vimentin and connective-tissue growth factor (CTGF). The mRNA and protein expression levels TGF-β, Smad-3, vimentin and CTGF were elevated, while ZO-1 mRNA and protein expression was decreased with the prolonged duration of dialysis treatment in the patients with PF. The experiments using the mouse model of PF revealed that the peritoneal connective tissue was thickened, while the numbers of inflammatory cells and blood vessels were increased. The expression levels of miR‑21, and the mRNA and protein expression levels of TGF-β, Smad-3, vimentin and CTGF were increased over time, whereas the mRNA and protein expression levels ZO-1 constantly decreased in the mice in the experimental group. Moreoever, the expression of miR‑21 positively correlated with the expression levels of TGF-β, Smad-3, vimentin and CTGF, while it negatively correlated with the expression of ZO-1. The results of H&E and Masson's staining revealed that miR‑21 expression was associated with the degree of PF. These findings thus indicate that miR‑21 promotes the progression of PF through the activation of the TGF-β/Smad signaling pathway.

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