Abstract
Objective: Diabetic nephropathy (DN) is one of the most severe and frequent diabetic complications. MicroRNAs (miRNAs) have been reported to play a vital role in DN pathogenesis. The present study aimed to investigate the molecular mechanism of miR-770-5p in DN.Methods: Podocyte injury model was established by treating mouse podocytes with high glucose (HG, 33 mM) for 24 h. The levels of miR-770-5p and TIMP3 were examined in kidney tissues and podocytes using quantitative real-time PCR (qRT-PCR). Flow cytometry analysis was applied to detect apoptosis in podocytes. Western blot assay was used to measure the protein levels of B-cell lymphoma 2 (Bcl-2), Bcl-2 associated X (Bax) and tissue inhibitors of metalloproteinase 3 (TIMP3). Enzyme-linked immunosorbent assay (ELISA) was conducted to measure the levels of inflammatory factors. The interaction between miR-770-5p and TIMP3 was determined by MicroT-CDS and luciferase reporter assay.Results: MiR-770-5p was up-regulated and TIMP3 was down-regulated in DN kidney tissues and HG-stimulated podocytes. Depletion of miR-770-5p suppressed cell apoptosis and the release of pro-inflammatory factors in HG-treated podocytes. Additionally, TIMP3 was a target of miR-770-5p in HG-treated podocytes. TIMP3 inhibited cell apoptosis and inflammation in HG-treated podocytes. Moreover, TIMP3 knockdown alleviated the inhibitory effect of miR-770-5p silencing on podocyte apoptosis and inflammatory response.Conclusion: Knockdown of miR-770-5p suppressed podocyte apoptosis and inflammatory response by targeting TIMP3 in HG-treated podocytes, indicating that miR-770-5p may be a potential therapeutic target for DN therapy.
Highlights
Diabetic nephropathy (DN) is a microvascular complication of diabetes and the leading cause of end-stage renal disease [1]
MiR-770-5p was up-regulated and tissue inhibitors of metalloproteinase 3 (TIMP3) was down-regulated in DN kidney tissues and high glucose (HG)-induced podocytes
The results of quantitative real-time PCR (qRT-PCR) and Western blot suggested that miR-770-5p expression was remarkably increased, while TIMP3 expression was dramatically decreased in renal tissues of DN patients compared with the negative control (NC) group (Figure 1A,C,D)
Summary
Diabetic nephropathy (DN) is a microvascular complication of diabetes and the leading cause of end-stage renal disease [1]. The typical hallmark of DN is the precipitation of extracellular matrix (ECM) in mesangium and renal tubulo-interstitium, and the thickening of glomerular and tubular basement membranes, resulting in glomerulosclerosis and tubulo-interstitial fibrosis [2]. Some progress has been made in DN treatment, the pathogenesis of DN still needs to be further explored to discover new biomarkers and therapeutic targets. Podocytes are a class of highly differentiated postmitotic cells involved in the glomerular filtration barrier [3]. Podocyte injury is considered to be an early pathological mechanism of various glomerular diseases, leading to glomerular filtration barrier dysfunction and proteinuria [4]. Increasing evidence demonstrated that apoptosis and autophagy play crucial roles in DN pathogenesis [5]. Programmed cell death is determined by the interaction between apoptosis-inhibiting and apoptosis-promoting protein in License 4.0 (CC BY)
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