MiR-92a-3p Knockdown Attenuates Transforming Growth Factor-β1-induced Tubulointerstitial Fibrosis by Targeting LIN28A-mediated EMT Pathway.

The role of microRNAs in regulating tubulointerstitial fibrosis, a key feature of progressive chronic kidney disease, is of significant importance. LIN28A has been reported to attenuate renal fibrosis in obstructive nephropathy. Here, our objective was to investigate the precise biological function of the miR-92a-3p/LIN28A axis in tubulointerstitial fibrosis. The human renal proximal tubular epithelial (HK-2) cell line was exposed to transforming growth factor (TGF)-β1, establishing an in vitro model mimicking tubulointerstitial fibrosis. Luciferase reporter assay was utilized to investigate the relationship between miR-92a-3p and LIN28A. Cell transfection techniques were employed to modify the expression of miR-92a-3p and LIN28A. An in vivo model of tubulointerstitial fibrosis was created by inducing unilateral ureteral obstruction (UUO) in C57BL/6N mice. Our initial observations showed that TGF-β1 treatment of HK-2 cells and the UUO mice model led to an increase in miR-92a-3p expression and a decrease in LIN28A expression. We confirmed that miR-92a-3p directly targeted LIN28A in HK-2 cells. In TGF-β1-stimulated HK-2 cells, knocking down miR-92a-3p notably reduced the levels of alpha smooth muscle actin and vimentin and concurrently enhanced the expression of E-cadherin. These changes were counteracted upon transfection with si-LIN28A. Thus, directing interventions toward miR-92a-3p holds the potential to emerge as a viable therapeutic approach for addressing tubulointerstitial fibrosis.

Xu M ，Pang M ，Wang C ，An N ，Chen R ，Bai Y ，He J ，Wang C ，Qi Y ... -  《-》

Mechanistic study on lncRNA XIST/miR-124-3p/ITGB1 axis in renal fibrosis in obstructive nephropathy.

The purpose of this study was to investigate the role and possible mechanism of lncRNA XIST in renal fibrosis and to provide potential endogenous targets for renal fibrosis in obstructive nephropathy (ON). The study included 50 cases of ON with renal fibrosis (samples taken from patients undergoing nephrectomy due to ON) and 50 cases of normal renal tissue (samples taken from patients undergoing total or partial nephrectomy due to accidental injury, congenital malformations, and benign tumors). Treatment of human proximal renal tubular epithelium (HK-2) cells with TGF-β1 simulated renal fibrosis in vitro. Cell viability and proliferation were measured by CCK-8 and EdU, and cell migration was measured by transwell. XIST, miR-124-3p, ITGB1, and epithelial-mesenchymal transition (EMT)-related proteins (E-cadherin, α-SMA, and fibronectin) were detected by PCR and immunoblot. The targeting relationship between miR-124-3p and XIST or ITGB1 was verified by starBase and dual luciferase reporter gene experiments. In addition, The left ureter was ligated in mice as a model of unilateral ureteral obstruction (UUO), and the renal histopathology was observed by HE staining and Masson staining. ON patients with renal fibrosis had elevated XIST and ITGB1 levels and reduced miR-124-3p levels. The administration of TGF-β1 exhibited a dose-dependent promotion of HK-2 cell viability, proliferation, migration, and EMT. Conversely, depleting XIST or enhancing miR-124-3p hindered HK-2 cell viability, proliferation, migration, and EMT in TGF-β1-damaged HK-2 cells HK-2 cells. XIST functioned as a miR-124-3p sponge. Additionally, miR-124-3p negatively regulated ITGB1 expression. Elevating ITGB1 weakened the impact of XIST depletion on TGF-β1-damaged HK-2 cells. Down-regulating XIST improved renal fibrosis in UUO mice. XIST promotes renal fibrosis in ON by elevating miR-124-3p and reducing ITGB1 expressions.

Zhang C ，Wang K ，Chen X ，Li Y ... -  《-》

The long noncoding RNA myocardial infarction-associated transcript modulates the epithelial-mesenchymal transition in renal interstitial fibrosis.

Renal interstitial fibrosis (RIF) is marked by the epithelial-mesenchymal transition (EMT) and excessive extracellular matrix deposition. The long noncoding RNA myocardial infarction-associated transcript (MIAT) facilitates RIF; however, the molecular mechanism of MIAT in RIF remains unclear. Here, we explored the possible underlying mechanisms through which MIAT modulates RIF. MIAT expression in human renal fibrotic tissues and unilateral ureteral obstruction (UUO) model mice was detected by qPCR. Transforming growth factor β1 (TGF-β1) was introduced to stimulate the EMT in human renal proximal tubular epithelial (HK-2) cells. CCK8, EdU, transwell and wound healing assays were employed to measure cell viability, proliferation, and migration respectively. RNA immunoprecipitation (RIP) assays and dual luciferase reporter assays were applied to determine the relationships among MIAT, miR-145, and EIF5A2. MIAT was upregulated in human renal fibrotic tissues and UUO model mice compared with normal tissue adjacent to renal tumors and sham operation mice, respectively. MIAT knockdown reduced cell viability, proliferation, migration, and the EMT in HK-2 cells. Additionally, MIAT served as an endogenous sponge for miR-145 in the TGF-β1-induced-EMT in HK-2 cells, as demonstrated by dual luciferase reporter assays and RIP assays. EIF5A2 was confirmed as a target of miR-145, and MIAT knockdown suppressed EIF5A2 expression by sponging miR-145. Downregulation of EIF5A2 partly reversed induction of the EMT by miR-145 inhibitor transfection. MIAT promoted cell viability, proliferation, migration, and the EMT via regulation of the miR-145/EIF5A2 axis. These data established a potential therapy for RIF.

Wang Z ，Zhang B ，Chen Z ，He Y ，Ru F ，Liu P ，Chen X ... -  《-》

Silencing of the lncRNA TUG1 attenuates the epithelial-mesenchymal transition of renal tubular epithelial cells by sponging miR-141-3p via regulating β-catenin.

Zhang B ，Zhao C ，Hou L ，Wu Y ... -  《-》

Total flavonoids from Smilax glabra Roxb blocks epithelial-mesenchymal transition and inhibits renal interstitial fibrosis by targeting miR-21/PTEN signaling.

Smilax glabra Roxb, a traditional Chinese herb, has been widely used in folk medicine. The current study was performed to investigate the protective effect of S. glabra Roxb extract, pure total flavonoids from Smilax glabra Roxb (PTFS), on renal interstitial fibrosis (RIF) and its underlying mechanism. First, a surgical model of unilateral ureteral obstruction was established in rats to induce RIF. Then, rats were grouped and treated with PTFS at different concentration. Second, HK-2 cells underwent an epithelial-mesenchymal transition (EMT) by the addition of transforming growth factor-β1 (TGF-β1). Additionally, HK-2 cells after inducing for EMT were transfected with microRNA-21 (miR-21) mimic or inhibitor. These HK-2 cells were grouped and treated with PTFS at different concentration. Finally, real-time polymerase chain reaction and Western blot analysis were performed to detect the expression of possible signaling factor involved in RIF in renal tissues or HK-2 cells after PTFS treatment. In vivo and in vitro experiments indicated that PTFS treatment could decrease the expression of α-smooth muscle actin (α-SMA; mesenchymal marker) and increase the expression of E-cadherin (epithelial marker) in both messenger RNA and protein level. Moreover, PTFS also attenuated the expression of TGF-β1/Smad signaling in both renal tissues and HK-2 cells that underwent EMT. Overexpression or inhibition of miR-21 in HK-2 cells activated or blocked the PI3K/Akt signaling via targeting phosphatase and tension homolog (PTEN), and then promoted or suppressed the progress of TGF-β1-induced EMT by regulating the expression of α-SMA and E-cadherin. Furthermore, PTFS treatment inhibited TGF-β1-induced EMT progress by blocking miR-21/PTEN/PI3K/Akt signaling. PTFS has strong anti-EMT and antifibrosis effects both in vitro and in vivo. The mechanism underlying these effects may be related to inhibition of TGF-β1/Smad, and their downstream miR-21/PTEN signaling, leading to blocks of EMT process during RIF.

Luo Q ，Cai Z ，Tu J ，Ling Y ，Wang D ，Cai Y ... -  《-》