Transition Of Podocytes Research Articles

SGLT2 inhibitors suppress epithelial-mesenchymal transition in podocytes under diabetic conditions via downregulating the IGF1R/PI3K pathway.

Loss of podocyte is a characteristic pathological change of diabetic nephropathy (DN) which is associated with increased proteinuria. Many studies have shown that novel inhibitors of sodium–glucose cotransporter 2 (SGLT2-is), such as dapagliflozin, exert nephroprotective effect on delaying DN progression. However, the mechanisms underlying SGLT2-associated podocyte injury are still not fully elucidated. Here, we generated streptozotocin-induced DN models and treated them with dapagliflozin to explore the possible mechanisms underlying SGLT2 regulation. Compared to mice with DN, dapagliflozin-treated mice exhibited remission of pathological lesions, including glomerular sclerosis, thickening of the glomerular basement membrane (GBM), podocyte injury in the glomeruli, and decreased nephrotoxin levels accompanied by decreased SGLT2 expression. The mRNA expression profiles of these treated mice revealed the significance of the insulin-like growth factor-1 receptor (IGF1R)/PI3K regulatory axis in glomerular injury. KEGG analysis confirmed that the phosphatidylinositol signaling system and insulin signaling pathway were enriched. Western blotting showed that SGLT2-is inhibited the increase of mesenchymal markers (α-SMA, SNAI-1, and ZEB2) and the loss of podocyte markers (nephrin and E-cad). Additionally, SGLT2, IGF1R, phosphorylated PI3K, α-SMA, SNAI-1, and ZEB2 protein levels were increased in high glucose-stimulated human podocytes (HPC) and significantly decreased in dapagliflozin-treated (50 nM and 100 nM) or OSI-906-treated (inhibitor of IGF1R, 60 nM) groups. However, the use of both inhibitors did not enhance this protective effect. Next, we analyzed urine and plasma samples from a cohort consisting of 13 healthy people and 19 DN patients who were administered with (n = 9) or without (n = 10) SGLT2 inhibitors. ELISA results showed decreased circulating levels of IGF1 and IGF2 in SGLT2-is-treated DN patients compared with DN patients. Taken together, our study reported the key role of SGLT2/IGF1R/PI3K signaling in regulating podocyte epithelial–mesenchymal transition (EMT). Modulating IGF1R expression may be a novel approach for DN therapy.

USP22 Mediates High Glucose-Induced Injury and Epithelial-Mesenchymal Transition in Podocytes via Regulating the RIPK3/MLKL Signaling Pathway

USP22 Mediates High Glucose-Induced Injury and Epithelial-Mesenchymal Transition in Podocytes via Regulating the RIPK3/MLKL Signaling Pathway

FC 005DEPOSITION OF PLATELET-DERIVED MICRO-PARTICLES IN PODOCYTES CONTRIBUTES TO DIABETIC NEPHROPATHY

Abstract Background and Aims Diabetic nephropathy (DN) is the leading cause of end-stage renal disease in the developed world. Podocyte injury has been shown to be a critical cellular event in the progression of DN. Our previous studies demonstrated that platelet-derived microparticles (PMPs) mediated endothelial injury in diabetic rats. Therefore, this study aimed to investigate whether the PMPs deposit in podocytes and its potential effects on podocyte injury in DN. Method Deposition of PMPs in podocytes was checked by immunofluorescent staining and electron microscopy. Renal pathological change and ultra-microstructure were respectively checked by periodic acid-schiff staining and electron microscopy. The protein expression of inflammatory cytokines and extracellular matrix was measured by immunohistochemical staining and Western blot. Results The PMPs were found to be widely deposited in podocytes of glomeruli in diabetic patients and animal models and closely associated with progression of DN. Interestingly, aspirin treatment significantly inhibited accumulation of PMPs in glomeruli of diabetic rats, accompanied with alleviated mesangial matrix expansion, fusion of foot processes, decreased protein expression of inflammatory cytokines and extracellular matrix secretion. The in vitro study further confirmed the deposition of PMPs in podocytes. Moreover, PMPs stimulation induced phenotype transition of podocytes through decreased protein expression of podocin and increased protein expression of α-SMA and fibronectin, which was correlated with increased production of inflammatory cytokines. Conclusion Our findings for the first time demonstrated that deposition of PMPs in podocytes contributed to the development of DN.

Knocking down TCF8 inhibits high glucose- and angiotensin II-induced epithelial to mesenchymal transition in podocytes.

Epithelial to mesenchymal transition (EMT) is a physiological phenomenon in mammalian embryogenesis by which epithelial cells become mesenchymal stem cells. Studies have indicated that an inappropriate EMT plays a key role in a variety of pathogenic processes such as embryonic development and tumor metastasis. Moreover, recent studies have indicated EMT also plays an important role in renal fibrosis. In the current study, glucose and angiotensin II promoted EMT in podocytes as well as changes in the cellular morphology of podocytes. A high concentration of glucose and angiotensin II also promoted podocyte movement and migration. Moreover, a high concentration of glucose and angiotensin II promoted TCF8 expression. Inhibiting TCF8 expression with siRNA reversed EMT in podocytes in the presence of a high concentration of glucose and angiotensin. Inhibiting TCF8 expression also reversed changes in cellular morphology and podocyte movement and migration. Therefore, glucose and angiotensin II may promote EMT in podocytes via TCF8.

CTGF mediates high-glucose induced epithelial–mesenchymal transition through activation of β-catenin in podocytes

Objective: It is known that connective tissue growth factor (CTGF) and β-catenin are involved in DN; however, the underlying molecular mechanisms remain unknown. Here we hypothesized that podocytes undergo epithelial–mesenchymal transition (EMT) in high-glucose condition and CTGF mediates high-glucose induced EMT by activating β-catenin in podocytes.Methods: The differentiated podocytes were cultured and divided into three groups: the normal glucose group (5 mmol/L glucose), the high-glucose group (30 mmol/L glucose), and the osmotic control group (5 mmol/L glucose supplemented with 25 mmol/L mannitol). The morphology of cultured podocytes was observed under phase contrast microscopy. To study the relevant markers of EMT, as well as CTGF and β-catenin, the mRNA and protein expressions were analyzed by real-time PCR and western blotting, respectively. In addition, the effects of inhibition CTGF by anti-CTGF antibody on high-glucose-induced EMT and β-catenin expression in podocytes were studied.Results: High glucose not only induced phenotypic transition of podocytes but also increased the expression of CTGF and β-catenin. Under high-glucose condition, podocytes underwent EMT, which were demonstrated by downregulation of nephrin and upregulation of desmin. Moreover, high-glucose-induced EMT and β-catenin overexpression in podocytes were attenuated by anti-CTGF antibody.Conclusion: CTGF and β-catenin are involved in the EMT of podocytes in diabetes. CTGF mediates high-glucose induced EMT through activation of β-catenin in podocytes. CTGF inhibition may protect podocytes from EMT in diabetes.

PTEN Inhibits High Glucose-Induced Phenotypic Transition in Podocytes

Accumulating evidence has suggested that podocytes undergo epithelial-mesenchymal transition (EMT) in diabetic nephropathy (DN). However, the underlying mechanisms of EMT in podocyte are not well understood. PI3K/Akt pathway is involved in the progression of DN. In the present study, we demonstrated that PI3K/Akt pathway was activated in podocytes exposed to high glucose conditions, accompanied by down-regulation of the podocalyxin (PCX) and nephrin expression and up-regulation of the desmin and α-smooth muscle actin (α-SMA) expression. Inhibition of PI3K/Akt pathway by chemical LY294002 or Phosphase and tensin homology deleted on chromosome ten (PTEN) prevented the phenotypic transition. These findings indicate that PTEN/PI3K/Akt pathway mediates high glucose-induced phenotypic transition in podocytes.

Curcumin ameliorates epithelial-to-mesenchymal transition of podocytes in vivo and in vitro via regulating caveolin-1

AimsEpithelial-mesenchymal transition (EMT) is recognized to play a key role in diabetic nephropathy (DN). Curcumin, the main active component of turmeric extracted from the roots of the Curcuma longa plant, has been reported for its anti-fibrotic effects in kidney fibrosis. The purpose of our study was to investigate the effects of curcumin in reversing epithelial-to-mesenchymal transition (EMT) of podocytes in vivo and in vitro. Materials/methodsIn vivo streptozotocin (STZ)-induced diabetic rats received vehicle or curcumin, and podocytes were treated with high glucose (HG) in the presence or absence of curcumin in vitro. And we investigated the effect of curcumin on HG-induced phosphorylation of cav-1 on the stability cav-1 and β-catenin using immunoprecipitation and fluorescence microscopy analysis. ResultsCurcumin treatment dramatically ameliorated metabolic parameters, renal function, morphological parameters in diabetic rats. We found that HG treatment led to significant down-regulation of p-cadherin and synaptopodin, as well as remarkable up-regulation of α-SMA and FSP-1 in vivo and in vitro. Furthermore, curcumin inhibited HG-induced caveolin-1 (cav-1) Tyr14 phosphorylation associating with the suppression of stabilization of cav-1 and β-catenin. ConclusionsIn summary, these findings suggest that curcumin prevents EMT of podocytes, proteinuria, and kidney injury in DN by suppressing the phosphorylation of cav-1, and increasing stabilization of cav-1 and β-catenin.

Effects of artificial cordyceps sinensis on epithelial-mesenchymal transition in the podocytes of diabetic rats

Objective To assess the effects of artificial cordyceps sinensis(Jin shuibao) on the numbers of podocytes and epithelial-mesenchymal transition in diabetic rats.Methods Diabetes was induced by intraperitoneal injection of low dose streptozocin.Sprague-Dawley rats were randomly divided into three groups:control group (CON),diabetic model group(DM),and artificial cordyceps sinensis treatment group(CS).After intervention for 8 weeks,the numbers of podocytes were estimated hy immunohistochemistry.The expressions of nephrin,desmin,and monocyte chemoattractant protein-1 (MCP-1) were detected.Results Compared with control group,DM group showed significantly decreased podocyte numbers and nephrin mRNA,with increased desmin and MCP-1 levels(P＜0.05).While the numbers of podocytes and nephrin mRNA were increased,and the expressions of desmin and MCP-1 were decreased in CS group as compared with those in DM group (all P＜0.05).Conclusions Artificial cordyceps sinensis notably improves epithelial-mesenchymal transition of podocytes,and increases the number of podocytes in diabetic rats. Key words: Artificial cordyceps sinensis; Diabetic nephropathy; Podocyte; Epithelial-mesenchymal transition ; Monocyte chemoattractant protein-1

Epithelial-to-mesenchymal transition in podocytes mediated by activation of NADPH oxidase in hyperhomocysteinemia

The present study tested the hypothesis that hyperhomocysteinemia (hHcys) induces podocytes to undergo epithelial-to-mesenchymal transition (EMT) through the activation of NADPH oxidase (Nox). It was found that increased homocysteine (Hcys) level suppressed the expression of slit diaphragm-associated proteins, P-cadherin and zonula occludens-1 (ZO-1), in conditionally immortalized mouse podocytes, indicating the loss of their epithelial features. Meanwhile, Hcys remarkably increased the abundance of mesenchymal markers, such as fibroblast specific protein-1 (FSP-1) and α-smooth muscle actin (α-SMA). These phenotype changes in podocytes induced by Hcys were accompanied by enhanced superoxide (O⁻₂) production, which was substantially suppressed by inhibition of Nox activity. Functionally, Hcys significantly enhanced the permeability of the podocyte monolayer coupled with increased EMT, and this EMT-related increase in cell permeability could be restored by Nox inhibitors. In mice lacking gp91( phox ) (gp91(-/-)), an essential Nox subunit gene, hHcys-enhanced podocyte EMT and consequent glomerular injury were examined. In wild-type (gp91(+/+)) mice, hHcys induced by a folate-free diet markedly enhanced expression of mesenchymal markers (FSP-1 and α-SMA) but decreased expression of epithelial markers of podocytes in glomeruli, which were not observed in gp91(-/-) mouse glomeruli. Podocyte injury, glomerular sclerotic pathology, and marked albuminuria observed in gp91(+/+) mice with hHcys were all significantly attenuated in gp91(-/-) mice. These results suggest that hHcys induces EMT of podocytes through activation of Nox, which represents a novel mechanism of hHcys-associated podocyte injury.

Homocysteine induces epithelial‐to‐mesenchymal transition of podocytes through the activation of NADPH oxidase

Our previous studies have demonstrated that hyperhomocyteinemia (hHcys) induced glomerulosclerosis through the activation of NADPH oxidase (Nox). However, it remains unknown how homocysteine (Hcys) produces detrimental effects on podocytes. The present study tested the hypothesis that Hcys may induce epithelial‐to‐mesenchymal transition (EMT) in podocytes through the activation of Nox. Mouse podocytes were incubated with L‐Hcys, a pathogenic isoform of Hcys. It was found that L‐Hcys (80 μM) induced a dramatic increase in the expression of Nox subunits and subsequent superoxide (O2.‐) production (2.9 folds vs. control), which was accompanied by significantly decreased expression of slit diaphragm‐associated protein, P‐cadherin and zonula occludens‐1, a change consistent with loss of the epithelial feature. Meanwhile, L‐Hcys induced the expression of mesenchymal markers, fibroblast‐specific protein‐1 and α‐smooth muscle actin. Nox inhibitors significantly reversed these Hcys‐induced changes in podocytes. In functional studies, L‐Hcys was found to increase dextran permeability across podocyte monolayers by 1.9 folds, which was inhibited by Nox inhibitors. These results suggest that an EMT occurs in podocytes due to cellular oxidative stress during hHcys and that enhanced EMT may result in podocyte dysfunction leading to glomerulosclerosis (supported by NIH grants DK54927 and HL075316).