Astragaloside IV improves renal function and fibrosis via inhibition of miR-21-induced podocyte dedifferentiation and mesangial cell activation in diabetic mice

Abstract

BackgroundPodocyte dedifferentiation and mesangial cell (MC) activation play an important role in many glomerular diseases associated with fibrosis. MicroRNA-21 (miR-21) is closely linked to renal fibrosis, but it is unknown whether and how miR-21 promotes podocyte dedifferentiation and MC activation and whether astragaloside IV (AS-IV) improves renal function and fibrosis through the regulation of miR-21.Materials and methodsCultured MCs, primary mouse podocytes, and diabetic KK-Ay mice were treated with AS-IV. Cell transfection, Western blot, real-time PCR, immunofluorescence assay, immunohistochemical assay, and electronic microscopy were used to detect the markers of podocyte dedifferentiation and MC activation and to observe the renal morphology.ResultsOur data showed that miR-21 expression was increased and that AS-IV decreased miR-21 levels in cells, serum, and kidney. Overexpressed miR-21 promoted podocyte dedifferentiation and MC activation, and treatment with AS-IV reversed this effect. Furthermore, the overexpression of miR-21 activated the β-catenin pathway and the transforming growth factor (TGF)-β1/Smads pathway in the process of podocyte dedifferentiation and MC activation, which was abolished by AS-IV treatment. In addition, both the Wnt/β-catenin pathway inhibitor XAV-939 and the TGF-β1/Smads pathway inhibitor SB431542 reversed the effect of AS-IV. Furthermore, AS-IV improved renal function and fibrosis in diabetic KK-Ay mice.ConclusionOur results indicated that AS-IV ameliorates renal function and renal fibrosis by inhibiting miR-21 overexpression-induced podocyte dedifferentiation and MC activation in diabetic kidney disease. These findings pave way for future studies investigating AS-IV as a potential therapeutic agent in the management of glomerular diseases.

Transcriptomic Analysis Reveals the Protection of Astragaloside IV against Diabetic Nephropathy by Modulating Inflammation

“…Recent studies have shown that AS-IV has potent antidiabetes, anti-inflammatory, antioxidative, antifibrotic, antihypertensive, and myocardial protective activities [13][14][15][16][17]. Furthermore, AS-IV treatment can inhibit the pathogenic process of DN in rodents [17][18][19][20][21][22][23][24]. In addition, AS-IV treatment ameliorates endoplasmic reticulum stress in renal tubular epithelial cells and improves renal function and fibrosis in animal models of DN [22,[25][26][27][28].…”

“…Furthermore, AS-IV treatment can inhibit the pathogenic process of DN in rodents [17][18][19][20][21][22][23][24]. In addition, AS-IV treatment ameliorates endoplasmic reticulum stress in renal tubular epithelial cells and improves renal function and fibrosis in animal models of DN [22,[25][26][27][28]. However, the molecular mechanisms underlying the pharmacological action of AS-IV remain unclear.…”

MicroRNAs in Podocyte Injury in Diabetic Nephropathy

“…Several previous studies reported that the OE or KD of different miRNAs had significant effects on podocyte injury in diabetic nephropathy in cultured podocyte cells stimulated with a high glucose concentration in vitro, and in rodent models with diabetic nephropathy in vivo (Tables 3A,B) (Long et al, 2010(Long et al, , 2011Chen et al, 2011Chen et al, , 2018Lin et al, 2014;Liu et al, 2015Liu et al, , 2016Liu et al, , 2017Badal et al, 2016;Yang et al, 2016;Zhang et al, 2016Zhang et al, , 2019Zhao et al, 2016;Guo et al, 2017;Kolling et al, 2017;Lee et al, 2017;Sun et al, 2017;Wang et al, 2017Wang et al, , 2018Zhou et al, 2017;Jiang et al, 2018;Mishra et al, 2018;Qian et al, 2018;Xu et al, 2018;Yao et al, 2018;Duan et al, 2019;Ming et al, 2019;Zha et al, 2019;Wei et al, 2020). These specific miRNAs are described below.…”

“…Several studies have examined the changes of expression levels of miRNAs in cultured podocyte cells stimulated with a high glucose concentration in vitro, and in podocytes in rodent models with diabetic nephropathy in vivo ( Table 1). The expression levels of 11 different miRNAs 193a, were shown to increase while the expression levels of 14 different miRNAs were shown to decrease in cultured podocytes in vitro or in podocytes in rodent models of diabetic nephropathy in vivo (Tables 1, 2) (Long et al, 2010(Long et al, , 2011Chen et al, 2011Chen et al, , 2018Lin et al, 2014;Liu et al, 2015Liu et al, , 2016Liu et al, , 2017Badal et al, 2016;Yang et al, 2016;Zhang et al, 2016Zhang et al, , 2019Zhao et al, 2016;Guo et al, 2017;Kolling et al, 2017;Lee et al, 2017;Sun et al, 2017;Wang et al, 2017Wang et al, , 2018Zhou et al, 2017;Jiang et al, 2018;Mishra et al, 2018;Qian et al, 2018;Xu et al, 2018;Yao et al, 2018;Duan et al, 2019;Zha et al, 2019;Wei et al, 2020). The associations between podocyte injury and miRNA expression levels in blood, urine, and kidney in patients with diabetic nephropathy were also reported ( Table 2) (Long et al, 2011;Zhao et al, 2016;Guo et al, 2017;Kolling et al, 2017;Lee et al, 2017;Liu et al, 2017;…”

“…The OE of miRNA-21 using miRNA-21 mimic was shown to decrease the expression levels of nephrin and increase the expression levels of α-SMA in cultured mouse podocyte cells with activation of the β-catenin pathway, and the TGF-β 1 /Smads pathway (Wang et al, 2018). Meanwhile, the KD of miRNA-21 expression dramatically reduced podocyte migration in cultured podocyte cells by regulating phosphatase and tensin homolog (Pten) (Kolling et al, 2017).…”