High Glucose-induced Epithelial-mesenchymal Transition Research Articles

Apigenin suppresses epithelial-mesenchymal transition in high glucose-induced retinal pigment epithelial cell by inhibiting CBP/p300-mediated histone acetylation

Epithelial mesenchymal transition (EMT) is a critical process implicated in the pathogenesis of retinal fibrosis and the exacerbation of diabetic retinopathy (DR) within retinal pigment epithelium (RPE) cells. Apigenin (AP), a potential dietary supplement for managing diabetes and its associated complications, has demonstrated inhibitory effects on EMT in various diseases. However, the specific impact and underlying mechanisms of AP on EMT in RPE cells remain poorly understood. In this study, we have successfully validated the inhibitory effects of AP on high glucose-induced EMT in ARPE-19 cells and diabetic db/db mice. Notably, our findings have identified CBP/p300 as a potential therapeutic target for EMT in RPE cells and have further substantiated that AP effectively downregulates the expression of EMT-related genes by attenuating the activity of CBP/p300, consequently reducing histone acetylation alterations within the promoter region of these genes. Taken together, our results provide novel evidence supporting the inhibitory effect of AP on EMT in RPE cells, and highlight the potential of specifically targeting CBP/p300 as a strategy for inhibiting retinal fibrosis in the context of DR.

2-Dodecyl-6-Methoxycyclohexa-2, 5-Diene-1, 4-Dione isolated from Averrhoa carambola L. root inhibits high glucose-induced EMT in HK-2 cells through targeting the regulation of miR-21–5p/Smad7 signaling pathway

Objective2-Dodecyl-6-Methoxycyclohexa-2, 5-Diene-1, 4-Dione (DMDD) isolated from Averrhoa carambola L. root, has been proven therapeutic effects on diabetic kidney disease (DKD). This research aims to assess DMDD’s effects on DKD and to investigate its underlying mechanisms, to establish DMDD as a novel pharmaceutical agent for DKD treatment. MethodsThe human renal tubular epithelial (HK-2) cells were induced by high glucose (HG) to mimic DKD and followed by DMDD treatment. The cytotoxicity of DMDD was assessed using the Cell Counting Kit-8 (CCK-8) assay. The migratory capacity of HK-2 cells was evaluated through transwell and scratch-wound assays. To investigate the effect of Smad7 and miR-21–5p, lentiviral transfection was employed in HK-2 cells. Additionally, the expression of proteins related to epithelial-mesenchymal transition (EMT) and TGFβ1/Smad2/3 pathway was checked by QRT-PCR, Western blot, and immunofluorescence techniques. ResultsThis study has shown that DMDD significantly suppresses cell migration and the expression of Vimentin, α-SMA, TGFβ1, and p-Smad2/3 in HK-2 cells under HG conditions. Concurrently, DMDD enhances the protein expression of E-cadherin and Smad7. Intriguingly, the therapeutic effect of DMDD was abrogated upon Smad7 silencing. Further investigations revealed that DMDD effectively inhibits miR-21–5p expression, which is upregulated by HG. Downregulation of miR-21–5p inhibits the activation of the TGFβ1/Smad2/3 pathway and EMT induced by HG. In contrast, overexpression of miR-21–5p negates DMDD’s therapeutic benefits. ConclusionDMDD mitigates EMT in HG-induced HK-2 cells by modulating the miR-21–5p/Smad7 pathway, thereby inhibiting renal fibrosis in DKD. These findings suggest that DMDD holds promise as a potential therapeutic agent for DKD.

SB431542 partially inhibits high glucose-induced EMT by restoring mitochondrial homeostasis in RPE cells

BackgroundThe epithelial–mesenchymal transition (EMT) of retinal pigment epithelial (RPE) cells participated in the development of retinal fibrosis. SB431542 is a small molecule inhibitor with inhibitory effects on the ALK4, ALK5 and ALK7. Our study aimed to explore the effect of SB431542 on the EMT of RPE cells and to provide new ideas for the treatment of retinal fibrosis.MethodsWe performed fundus fluorescein angiography, optical coherence tomography and hematoxylin–eosin staining in vivo to observe the effect of SB431542 on choroidal neovascularization (CNV)-induced retinopathy. The proliferation, migration, cytoskeleton, adhesion, reactive oxygen species (ROS), mitochondrial morphology and membrane potential of RPE cells were observed in vitro through fluorescein diacetate staining, Cell Counting Kit-8 experiment, wound healing assay, phalloidin staining, immunofluorescence, MitoSOX, DCFH-DA, MitoTracker and JC-10 staining. Western blot, reverse transcription quantitative and immunofluorescence were used to detect the expression of EMT–related markers, pERK1/2, pGSK3β and β-catenin.ResultsSB431542 significantly alleviated retinopathy in the CNV model. The proliferation, migration and adhesion in RPE cells decreased to a certain extent in SB431542 treatment. SB431542 partially normalized the structure of RPE cells. The expression levels of E-cadherin increased, while the expression levels of laminin and N-cadherin decreased with SB431542 treatment. SB431542 reduced the production of total ROS, mitochondrial SOX and recovered the mitochondrial membrane potential to a certain degree. In addition, our study showed that SB431542 downregulated the phosphorylation of ERK1/2, GSK3β and the expression of β-catenin.ConclusionSB431542 improved EMT in RPE cells by maintaining mitochondrial homeostasis via the ERK1/2 and GSK3β/β-catenin pathways.1HzEs7TmoETCuNYu8FcEmbVideo Graphical SB431542 inhibits EMT in RPE cells under high glucose conditions.

Exosomes derived from mesenchymal stem cells attenuate diabetic kidney disease by inhibiting cell apoptosis and epithelial-to-mesenchymal transition via miR-424-5p.

Diabetic kidney disease (DKD) is well-acknowledged as one of the most common complications in diabetes mellitus. Recent studies have demonstrated the promising role of mesenchymal stem cell-derived exosomes (MSC-exos) as a cell-free treatment strategy for DKD. The present study sought to investigate the therapeutic potential and the underlying mechanisms of MSC-exos in DKD. The authentication of MSC-exos was validated by western blot, transmission electron microscope (TEM), and nanosight tracking analysis (NTA). Apoptosis was detected by western blot, TUNEL staining, and flow cytometry. Epithelial-to-mesenchymal transition (EMT) was evaluated by western blot and immunofluorescence. The relationship between miR-424-5p and Yes-associated protein 1 (YAP1) was revealed by dual luciferase reporter assay. We observed that MSC-exos could attenuate DKD by decreasing cell apoptosis and inhibiting epithelial-to-mesenchymal transition (EMT) in diabetic kidneys in db/db mice. Besides, we documented that MSC-exos could reverse high glucose-induced apoptosis and EMT in HK2 cells. Interestingly, miR-424-5p derived from MSC-exos could inhibit YAP1 activation in HK2 cells, resulting in alleviation of high glucose-induced cell apoptosis and EMT. Our study provides novel insights into MSC-exos-mediated protective effect in DKD. MSC-exos could inhibit high glucose-induced apoptosis and EMT through miR-424-5p targeting of YAP1.

Berberine protects diabetic nephropathy by suppressing epithelial-to-mesenchymal transition involving the inactivation of the NLRP3 inflammasome

Accumulating evidence has implicated that berberine (BBR) has a beneficial effect on diabetic kidney disease (DKD), but its mechanism is not clear. The aim of this study was to assess whether berberine could alleviate tubulointerstitial fibrosis and attenuate epithelial-to-mesenchymal transition (EMT) and its possible molecular mechanism. High-fat diet (HFD) followed by injection of STZ was used to induce diabetic rats in vivo. After the onset of diabetes, rats were treated with either BBR or saline for 12 weeks. In vitro, the human renal proximal tubular epithelial cell line (HK-2) was exposed to high glucose, with or without BBR. The influence of berberine on renal tubulointerstitial histological changes, markers of epithelial-to-mesenchymal transition (EMT) and (NOD-like receptor pyrin domain-containing protein 3) NLRP3 inflammasome expression were examined. Results showed that in vivo, BBR could significantly ameliorate microalbumin and renal pathologic changes in diabetic rats. Immunofluorescence showed that BBR could inhibit EMT. Furthermore, BBR could down-regulate the level of the NLRP3 inflammasome in diabetic rats. Consistently, in vitro, BBR suppressed high glucose-induced EMT and activation of NLRP3 inflammasome in HK-2. Our study demonstrated that BBR could inhibit high glucose-induced EMT and renal interstitial fibrosis by suppressing the NLRP3 inflammasome. BBR might be used as a novel drug to ameliorate tubulointerstitial fibrosis in DKD.

Etoposide-induced protein 2.4 ameliorates high glucose-induced epithelial-mesenchymal transition by activating adenosine monophosphate-activated protein kinase pathway in renal tubular cells.

Epithelial-mesenchymal transition (EMT), known as the transition of tubular epithelial cells into fibroblasts, is one of the potential mechanisms of renal fibrosis, which promotes the development of diabetic kidney disease (DKD). Etoposide-induced protein 2.4 (EI24) is known as an endoplasmic reticulum (ER)-localized Bcl-2-binding transmembrane protein with various functions that can affect autophagy, apoptosis and differentiation. However, whether EI24 is involved in EMT of renal tubular epithelial cells and the exact mechanism is still not known. In this study, we first reported that EI24 expression was significantly downregulated in the kidneys of diabetic mice and in high glucose-stimulated HK2 cells. Knockdown of EI24 led to EMT of HK2 cells, as indicated by decreased E-cadherin and increased α-smooth muscle actin (α-SMA). Meanwhile, overexpression of EI24 ameliorated high glucose-induced EMT of HK2 cells via activation of the adenosine monophosphate-activated protein kinase (AMPK) pathway. Then, DNA methyltransferase (DNMT) inhibitor 5-Aza-2'-deoxycytidine (5-Aza) treatment enhanced EI24 expression and alleviated EMT in high glucose-treated HK2 cells and the kidneys of diabetic mice. Furthermore, DNMT1 and DNMT3a upregulation were found to be involved in the decrease of EI24 in high glucose-stimulated HK2 cells. Silencing of DNMT1 and DNMT3a effectively reversed high glucose-induced downregulation of EI24 and aggravation of EMT. Our findings demonstrate that the DNA methyltransferase-regulated EI24 affects EMT of renal tubular cells via AMPK signaling pathway. It is suggested that EI24 may be a potential therapeutic target for diabetic renal injury.

Tanshinone IIA attenuates high glucose-induced epithelial-to-mesenchymal transition in HK-2 cells through VDR/Wnt/β-catenin signaling pathway.

The progression of diabetic kidney disease (DKD) is closely related to renal tubular epithelial- to-mesenchymal transition (EMT) and tubulointerstitial fibrosis. Tanshinone IIA (TSIIA), extracted from a traditional Chinese medicine named Salvia miltiorrhiza, has been proved to have anti-fibrosis effects. The aim of this study was to investigate the effect of TSIIA on high glucose-induced EMT in human proximal tubular cells (HK-2 cells) and its possible mechanism. The proliferation of cells exposed to different concentrations of glucose was measured by light microscopy and CCK-8 test. The cells were stimulated with 30 mM glucose and different concentrations of TSIIA (5 μM or 10 μM) for 48 h. Vitamin D receptor (VDR)-siRNA was used to transfect cells, and high glucose and TSIIA treatment were further used to treat cells. The expression of alpha smooth muscle actin (a-SMA) mRNA was detected by qPCR to ensure successful induction of EMT, and the expression of VDR mRNA was detected by qPCR to ensure successful transfection of VDR-siRNA. Protein expression of a-SMA, E-cadherin, VDR, b-catenin and glycogen synthase kinase 3b (GSK-3b) was detected by Western blot analysis. The results showed that high glucose concentration inhibited cell proliferation and promoted EMT in HK-2 cells. TSIIA could reverse high glucose-induced EMT by increasing the level of VDR protein and inhibiting the levels of b-catenin and GSK-3b proteins suggestive of a negative correlation between VDR and the Wnt/b-catenin pathway. After VDR-siRNA transfection and incubation of cells at high glucose concentration, the inhibitory effect of VDR on the expression of b-catenin and GSK-3b of Wnt pathway was suppressed and the b-catenin pathway was activated. When VDR level was restored by TSIIA, the inhibitory effect of VDR on the pathway was also restored and the activation of the pathway was suppressed. TSIIA was able to attenuate high glucose-induced EMT in HK-2 cells by up-regulating VDR levels, which might be related to the inhibitory effect of VDR on the Wnt pathway.

C-peptide ameliorates high glucose-induced podocyte dysfunction through the regulation of the Notch and TGF-β signaling pathways

The podocyte is one of the main components of the glomerular filtration barrier in the kidney, and its injury may contribute to proteinuria, glomerulosclerosis and eventually kidney failure. C-peptide, a cleavage product of proinsulin, shows therapeutic potential for treating diabetic nephropathy (DN). The aim of this study was to investigate the effect of C-peptide on high glucose-induced podocyte dysfunction. In the present study, we found that the protective effects of islet transplantation were superior to simple insulin therapy for the treatment of DN in streptozotocin (STZ)-treated rats. And such superiority may due to the function of C-peptide secreted at the implanted site. Based on this background, we determined that the application of C-peptide significantly prevented high glucose-induced podocyte injury by increasing the expression of nephrin and synaptopodin. Meanwhile, C-peptide suppressed high glucose-induced epithelial-mesenchymal transition (EMT) and renal fibrosis via decreasing the expression of snail, vimentin, α-smooth muscle actin (α-SMA) and connective tissue growth factor (CTGF). Moreover, the Notch and transforming growth factor-β (TGF-β) signaling pathways were activated by high glucose, and treatment with C-peptide down-regulated the expression of the Notch signaling molecules Notch 1 and Jagged 1 and the TGF-β signaling molecule TGF-β1. These findings suggested that C-peptide might serve as a novel treatment method for DN and podocyte dysfunction.

Kaempferol amelioratesthe regulatory effects of PVT1/miR-214 on epithelial-mesenchymal transitionthrough thePAK4/β-catenin axis in SRA01/04 cells.

Aim: To investigate whether kaempferol exhibitsaprotective effecton high glucose-induced epithelial-mesenchymal transition (EMT) by mediating thePVT1/miR-214 and PAK4/β-catenin pathways in SRA01/04 cells. Methods & methods: qRT-PCR and western blot assays were used for geneand proteindetermination, andmigration and invasion assays were conducted. A coimmunoprecipitation assay was used for determining proteininteractions. Results: High glucose effectively upregulated PVT1 expression, downregulated miR-214 expressionand promoted cell migration and invasion. Kaempferol attenuated high glucose-induced EMT by increasing PVT1 expression and decreasing miR-214 expression. PAK4 was identified as a direct target of miR-214. PAK4 overexpression could rescue the effects of PVT1 deficiency on SRA01/04 cells. Conclusion: Kaempferol ameliorated the regulatory effects of PVT1/miR-214 on high glucose-induced EMT through PAK4/β-catenin in SRA01/04 cells.

Activation of autophagy inhibits epithelial to mesenchymal transition process of human lens epithelial cells induced by high glucose conditions

Subcapsular cataracts are common phenotype of diabetic cataracts, and abnormal lens epithelial cells (LECs) under the lens capsules have been considered to involve in the pathogenesis. Our previous studies have shown that the epithelial to mesenchymal transition (EMT), which is responsible for the LECs to lose their original polarity and tight junctions, occurs in a diabetic cataract mouse model. Autophagy is known to function in the EMT process in multiple tissues. However, the relationship between autophagy and EMT process in LECs has not yet been fully demonstrated. We found that high glucose retreatment reducing expression level of E-cadherin, an epithelial marker, but increasing that of α-smooth muscle actin (α-SMA), a mesenchymal marker, by Western blot and immunoflurence staining assays, and increased the cell migration by Transwell assay in human lens epithelial cell line HLE-B3. High glucose retreatment also led to impairment of autophagy, representing by downregulation of Beclin, LC3II/LC3I, and reducing the number of autophagosomes. Activation of autophagy by rapamycin could prevent high glucose-induced EMT. In addition, the levels of p62 and Snail were increased in high glucose-treated HLE-B3 cells, and their interactions were demonstrated by co-immunoprecipitation and immunoflurence staining, but all these changes were attenuated by application of rapamycin. These findings delineated a novel autophagy-mediated mechanism, p62 might mediate Snail underlying high glucose-induced EMT in LECs, suggesting a potential therapeutic approach for diabetic cataract by regulating autophagy.

Dexmedetomidine Attenuates High Glucose-induced HK-2 Epithelial-mesenchymal Transition by Inhibiting AKT and ERK

ObjectiveTo explore the protective effects of dexmedetomidine (Dex) against high glucose-induced epithelial-mesenchymal transition in HK-2 cells and relevant mechanisms. MethodsHK-2 cells were exposed to either glucose or glucose+Dex for 6 h. The production of ROS, morphology of HK-2 cells, and cell cycle were detected. Moreover, the expression of AKT, p-AKT, ERK, p-ERK, PI3K, E-Cadherin, Claudin-1, and α-SMA were determined and compared between HK-2 cells exposed to glucose and those exposed to both glucose and Dex with or without PI3K/AKT pathway inhibitor LY294002 and ERK pathway inhibitor U0126. ResultsCompared with HK-2 cells exposed to high level of glucose, the HK-2 cells exposed to both high level of glucose and Dex showed: (1) lower level of ROS production; (2) cell morphology was complete; (3) more cells in G1 phase; (4) lower expression of p-AKT, p-ERK and α-SMA, higher expression of E-Cadherin and Claudin-1. PI3K/AKT inhibitor LY294002 and ERK inhibitor U0126 decreased the expression of p-AKT, p-ERK and α-SMA, and increased the expression of E-Cadherin and Claudin-1. ConclusionDex can attenuate high glucose-induced HK-2 epithelial-mesenchymal transition by inhibiting AKT and ERK.

Astragaloside IV attenuates high glucose-induced EMT by inhibiting the TGF-β/Smad pathway in renal proximal tubular epithelial cells.

In the present study, we examined the molecular mechanism of astragaloside IV (AS-IV) in high glucose (HG)-induced epithelial-to-mesenchymal transition (EMT) in renal proximal tubular epithelial cells (PTCs). NRK-52E cell viability and apoptosis were determined by the cell counting kit-8 (CCK-8) assay and flow cytometric analysis, respectively. Expressions of E-cadherin, N-cadherin, vimentin, and occludin were measured by Western blot, and those of E-cadherin and N-cadherin were additionally measured by immunofluorescence analysis. Transforming growth factor-β1 (TGF-β1) and α-smooth muscle actin (α-SMA) expressions were detected by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot. The expressions of Smad2, Smad3, phosphorylated-Smad2 (p-Smad2), and p-Smad3 were measured using Western blot. We found that AS-IV could recover NRK-52E cell viability and inhibit HG-induced cell apoptosis. TGF-β1, α-SMA, Smad2, Smad3, p-Smad2, and p-Smad3 expressions were decreased in the AS-IV-treated groups compared with the HG group. Moreover, the expressions of E-cadherin and occludin were remarkably up-regulated and those of N-cadherin and vimentin were down-regulated in the AS-IV-treated groups compared with the HG group. Interestingly, the TGF-β1 activator SRI-011381 hydrochloride had an antagonistic effect to AS-IV on HG-induced EMT behavior. In conclusion, AS-IV attenuates HG-induced EMT by inhibiting the TGF-β/Smad pathway in renal PTCs.

Insulin exacerbated high glucose-induced epithelial-mesenchymal transition in prostatic epithelial cells BPH-1 and prostate cancer cells PC-3 via MEK/ERK signaling pathway

As two most common progressive diseases of aging, type 2 diabetes mellitus (T2DM) and benign prostatic hyperplasia (BPH) were all characterized by endocrine and metabolic disorders. Here, our clinical study showed that there were significant differences in fasting blood glucose (FBG), fasting insulin (FINS), insulin resistance index (HOMA-IR) and prostate volume (PV) between simple BPH patients and BPH complicated with T2DM patients. Further analysis showed that HOMA-IR was positively correlated with PV in BPH complicated with T2DM patients. The in vitro experiment results showed that high glucose (HG) promoted EMT process in a glucose-dependent manner in human prostate hyperplasia cells (BPH-1) and prostate cancer cells (PC-3), and this pathological process was exacerbated by co-culture with insulin. Mechanistically, insulin-induced exacerbation of EMT was depended on the activation of MEK/ERK signaling pathway, and we suggested that insulin and its analogs should be used very carefully for the clinical antihyperglycemic treatment of BPH complicated with T2DM patients.

Autophagy regulates high glucose-induced epithelial-mesenchymal transition in human lens epithelial cells

Autophagy regulates high glucose-induced epithelial-mesenchymal transition in human lens epithelial cells

Lefty-1 inhibits renal epithelial-mesenchymal transition by antagonizing the TGF-β/Smad signaling pathway.

Epithelial-mesenchymal transition (EMT) is a biological process in which tubular epithelial cells lose their phenotypes, and new mesenchymal feature are obtained. In particular, type II EMT possibly contributes to renal tissue fibrogenesis. Recent studies indicate that Lefty-1, a novel member of the TGF-β superfamily with pleiotropical and biological regulation characteristics on TGF-β and other signaling pathways, is considered to have potential fibrotic effects. However, its role in EMT, which is often a long-term consequence of renal tubulointerstitial fibrosis, remains unknown. In this study, we found that Lefty-1 alleviates EMT induction through antagonizing TGF-β/Smad pathway in vivo and in vitro. In unilateral ureteral obstruction (UUO) model mice, administration of adenovirus-mediated overexpression of Lefty-1 (Ad-Lefty-1) significantly reduced TGF-β1/Smad expression and alleviated the phenotypic transition of epithelial cells to mesenchymal cells and extracellular matrix (ECM) accumulation. In high glucose-induced rat renal tubular duct epithelial cell line (NRK-52E), EMT and ECM synthesis were alleviated with Lefty-1 treatment, which significantly inhibited TGF-β1/Smad pathway activation in UUO mice and high glucose-treated NRK-52E cells. Thus, Lefty-1 can alleviate EMT and renal interstitial fibrosis in vivo and in vitro through antagonizing the TGF-β/Smad pathway, and Lefty-1 might have a potential novel therapeutic effect on fibrotic kidney diseases.

MiR-30c-5p inhibits high glucose-induced EMT and renal fibrogenesis by down-regulation of JAK1 in diabetic nephropathy.

Diabetic nephropathy (DN) is one of the most serious complications of diabetes mellitus (DM) and has become the major cause of end-stage renal failure. MicroRNAs (miRs) play key roles in many pathologic processes for initiating and progressing, including DN. Epithelial-mesenchymal transition (EMT) and renal fibrogenesis are important features of DN. However, the role of miR-30c-5p in high glucose (HG)-induced EMT and renal fibrogenesis is not clear. This study was aimed at determining the regulatory network of miR-30c-5p and JAK1 in DN. Quantitative Real Time-Polymerase Chain Reaction (qRT-PCR) and Western blot assays were performed to detect expressions of miR-30c-5p, JAK1, vimentin, α-SMA, and E-cadherin. The possible binding sites between miR-30c-5p and JAK1 were predicted by TargetScan online database and verified by Luciferase report assay. The secretion of fibronectin (FN) andCollagen IV (Col IV) in the supernatant was detected by Enzyme-linked immunosorbent (ELISA) assay. MiR-30c-5p was downregulated and JAK1 was upregulated in renal fibrosis tissue and HG stimulated HK2 cells. Transfection of miR-30c-5p inhibited HG-induced EMT and renal fibrogenesis in HK2 cells, which was reversed by miR-30c-5p inhibitor. Moreover, JAK1 was confirmed as a direct target of miR-30c-5 and knockdown of JAK1 markedly inhibited HG-induced renal fibrogenesis and EMT in HK2 cells. Furthermore, overexpression of JAK1 attenuated the inhibitory effect of miR-30c-5p on HG-induced EMT and renal fibrogenesis in HK2 cells. MiR-30c-5p evidently inhibited HG-induced EMT and renal fibrogenesis by down-regulation JAK1 in DN, providing a promising therapeutic strategy for the treatment of DN.

Ginsenoside Rg1 Alleviates Podocyte EMT Passage by Regulating AKT/GSK3 β/β-Catenin Pathway by Restoring Autophagic Activity.

Background Diabetic nephropathy (DN), a complication of diabetes, is the result of high glucose-induced pathological changes in podocytes, such as epithelial-mesenchymal transition (EMT). Autophagy is an important mechanism of podocyte repair. Ginsenoside Rg1, the active ingredient of ginseng extract, has antifibrotic and proautophagic effects. Therefore, we hypothesized that ginsenoside Rg1 can reverse podocyte EMT via autophagy and alleviate DN. Aim This study aimed to investigate the effect of ginsenoside Rg1 on DN rats and high glucose-induced podocyte EMT by regulating the AKT/GSK3β/β/Methods Diabetic rats induced by STZ injection were treated with 50 mg/kg ginsenoside Rg1 for 8 weeks, and the renal functional, metabolic, and histopathological indices were evaluated. DN was simulated in vitro by exposing podocytes to high glucose levels and treated with ginsenoside Rg1. The expression of EMT and autophagy-related markers was analyzed in vivo and in vitro by exposing podocytes to high glucose levels and treated with ginsenoside Rg1. The expression of EMT and autophagy-related markers was analyzed Results Ginsenoside Rg1 significantly alleviated renal fibrosis and podocyte EMT in diabetic rats, and podocytes exposed to high glucose levels, which was abolished by the autophagy inhibitor 3-MA. Furthermore, ginsenoside Rg1 regulated the AKT/GSK3 β/β/Conclusion Ginsenoside Rg1 alleviated podocyte EMT by enhancing AKT/GSK3β/β-catenin pathway-mediated autophagy, indicating its therapeutic potential for DN and other glomerular diseases.β/β/

LncRNA ZEB1-AS1 inhibits high glucose-induced EMT and fibrogenesis by regulating the miR-216a-5p/BMP7 axis in diabetic nephropathy.

Diabetic nephropathy (DN) is one of the leading causes of mortality in diabetic patients. Long non-coding RNA zinc finger E-box binding homeobox 1 antisense 1 (ZEB1-AS1) plays a crucial role in the development of various diseases, including DN. However, the molecular mechanism of ZEB1-AS1 in DN pathogenesis remains elusive. An in vitro DN model was established by treating HK-2 cells with high glucose (HG). Quantitative polymerase chain reaction (qRT-PCR) was utilized to detect the expression levels of ZEB1-AS1, microRNA-216a-5p (miR-216a-5p), and bone morphogenetic protein 7 (BMP7). Western blot assay was used to evaluate the protein levels of BMP7, epithelial-to-mesenchymal transition (EMT)-related proteins, and fibrosis markers. Additionally, the interaction among ZEB1-AS1, miR-216a-5p, and BMP7 was predicted by MiRcode (http://www.mircode.org) and starBase 2.0 (omics_06102, omicX), and confirmed by luciferase reporter assay. ZEB1-AS1 and BMP7 were down-regulated, while miR-216a-5p was highly expressed in kidney tissues of DN patients. Consistently, HG treatment decreased the levels of ZEB1-AS1 and BMP7, whereas HG increased miR-216a-5p expression in HK-2 cells in a time-dependent manner. ZEB1-AS1 upregulation inhibited HG-induced EMT and fibrogenesis. Furthermore, ZEB1-AS1 directly targeted miR-216a-5p, and overexpression of miR-216a-5p restored the inhibitory effects of ZEB1-AS1 overexpression on EMT and fibrogenesis. BMP7 was negatively targeted by miR-216a-5p. In addition, ZEB1-AS1 suppressed HG-induced EMT and fibrogenesis by regulating miR-216a-5p and BMP-7. lncRNA ZEB1-AS1 inhibited high glucose-induced EMT and fibrogenesis via regulating miR-216a-5p/BMP7 axis in diabetic nephropathy, providing a potential target for DN therapy.

Nitro-oleic acid inhibits the high glucose-induced epithelial-mesenchymal transition in peritoneal mesothelial cells and attenuates peritoneal fibrosis.

As an electrophilic nitroalkene fatty acid, nitro-oleic acid (OA-NO2) exerts multiple biological effects that contribute to anti-inflammation, anti-oxidative stress, and antiapoptosis. However, little is known about the role of OA-NO2 in peritoneal fibrosis. Thus, in the present study, we examined the effects of OA-NO2 on the high glucose (HG)-induced epithelial-mesenchymal transition (EMT) in human peritoneal mesothelial cells (HPMCs) and evaluated the morphological and immunohistochemical changes in a rat model of peritoneal dialysis-related peritoneal fibrosis. In in vitro experiments, we found that HG reduced the expression level of E-cadherin and increased Snail, N-cadherin, and α-smooth muscle actin expression levels in HPMCs. The above-mentioned changes were attenuated by pretreatment with OA-NO2. Additionally, OA-NO2 also inhibited HG-induced activation of the transforming growth factor-β1/Smad signaling pathway and NF-κB signaling pathway. Meanwhile, OA-NO2 inhibited HG-induced phosphorylation of Erk and JNK. The results from the in vivo experiments showed that OA-NO2 notably relieved peritoneal fibrosis by decreasing the thickness of the peritoneum; it also inhibited expression of transforming growth factor-β1, α-smooth muscle actin, N-cadherin, and vimentin and enhanced expression of E-cadherin in the peritoneum. Collectively, these results suggest that OA-NO2 inhibits the HG-induced epithelial-mesenchymal transition in HPMCs and attenuates peritoneal dialysis-related peritoneal fibrosis.

ROS induces epithelial-mesenchymal transition via the TGF-β1/PI3K/Akt/mTOR pathway in diabetic nephropathy.

Oxidative stress has been reported to serve an important role in the development and progression of diabetic nephropathy (DN). Epithelial-mesenchymal transition (EMT) of renal tubular epithelial cells promotes renal fibrosis in DN, while the mechanism of reactive oxygen species (ROS)-mediated EMT is not fully understood. The aim of the present study was to investigate the effect of high glucose-induced ROS on the activation of the transforming growth factor (TGF)-β1/phosphoinositide 3 kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) pathway in a normal rat kidney tubular epithelial cell line (NRK-52E) and rats with type 1 diabetes. In vitro, high glucose-stimulated ROS production resulted in increased TGF-β1 expression as well as an increase in the Akt and mTOR phosphorylation ratio, resulting in EMT. When cells were pre-treated with ROS inhibitors, changes in TGF-β1, Akt and mTOR were significantly ameliorated. In vivo, diabetic rats experienced a significant decline in renal function and severe renal fibrosis compared with control rats at 8 weeks following streptozocin injection. Levels of malondialdehyde and TGF-β1/PI3K/Akt/mTOR pathway activation were increased in the renal cortex of rats with diabetes compared with the control rats. Furthermore, renal fibrosis was further aggravated in DN compared with the control rats. The results of the present study suggest that ROS serves an important role in mediating high glucose-induced EMT and inhibits activation of the TGF-β1/PI3K/Akt/mTOR pathway. ROS may therefore have potential as a treatment approach to prevent renal fibrosis in DN.