Baicalin reversal of DNA hypermethylation-associated Klotho suppression ameliorates renal injury in type 1 diabetic mouse model.
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ABSTRACT:
SUBMITTER: Zhang XT
PROVIDER: S-EPMC7751632 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Rap1b ameliorates high glucose (HG)-induced mitochondrial dysfunction in tubular cells. However, its role and precise mechanism in diabetic nephropathy (DN) in vivo remain unclear. We hypothesize that Rap1 plays a protective role in tubular damage of DN by modulating primarily the mitochondria-derived oxidative stress. The role and precise mechanisms of Rap1b on mitochondrial dysfunction and of tubular cells in DN were examined in rats with streptozotocin (STZ)-induced diabetes that have Rap1b gene transfer using an ultrasound microbubble-mediated technique as well as in renal proximal epithelial tubular cell line (HK-2) exposed to HG ambiance. The results showed that Rap1b expression decreased significantly in tubules of renal biopsies from patients with DN. Overexpression of a constitutively active Rap1b G12V notably ameliorated renal tubular mitochondrial dysfunction, oxidative stress, and apoptosis in the kidneys of STZ-induced rats, which was accompanied with increased expression of transcription factor C/EBP-? and PGC-1?. Furthermore, Rap1b G12V also decreased phosphorylation of Drp-1, a key mitochondrial fission protein, while boosting the expression of genes related to mitochondrial biogenesis and antioxidants in HK-2 cells induced by HG. These effects were imitated by transfection with C/EBP-? or PGC-1? short interfering RNA. In addition, Rap1b could modulate C/EBP-? binding to the endogenous PGC-1? promoter and the interaction between PGC-1? and catalase or mitochondrial superoxide dismutase, indicating that Rap1b ameliorates tubular injury and slows the progression of DN by modulation of mitochondrial dysfunction via C/EBP-?-PGC-1? signaling.
| S-EPMC3964498 | biostudies-literature
Project description:To explore whether epigallocatechin-3-gallate (EGCG) improves renal damage in diabetic db/db mice and high-glucose- (HG-) induced injury in HK-2 cells by regulating the level of Klotho gene promoter methylation. Western blotting was used to detect the protein expression levels of DNA methyltransferase 1 (DNMT1), DNMT3a, DNMT3b, transforming growth factor-β1 (TGF-β1), α-smooth muscle actin (α-SMA), and Klotho. The methylation level of the Klotho gene promoter was detected by pyrosequencing. Chromatin immunoprecipitation was used to detect the binding of the Klotho gene promoter to DNMT1 and DNMT3a. The expression of oxidative stress markers (reactive oxygen species (ROS), superoxide dismutase (SOD), malondialdehyde (MDA), catalase (CAT), and 8-hydroxy-2'-deoxyguanosine (8-OHdG)) and inflammatory cytokines (interleukin-1β (IL-1β), IL-6, and tumor necrosis factor-α (TNF-α)) in kidney homogenates was also measured using ELISA. Klotho and DNMT3b protein expression was upregulated, while DNMT1, DNMT3a, TGF-β1, and α-SMA protein expression was downregulated after EGCG treatment. EGCG treatment also reduced the methylation level of the Klotho gene promoter as well as the binding of DNMT3a to the Klotho gene promoter. In addition, EGCG treatment significantly decreased the levels of ROS, MDA, 8-OHdG, IL-1β, IL-6, and TNF-α and increased the levels of CAT and SOD. Under HG conditions, EGCG regulated Klotho gene promoter methylation via DNMT3a and decreased the methylation level of the Klotho gene promoter, thereby upregulating the expression of the Klotho protein to exert its protective effect.
| S-EPMC7474393 | biostudies-literature
Project description:Fibrosis is an exaggerated form of tissue repair that occurs with serious damage or repetitive injury and ultimately leads to organ failure due to the excessive scarring. Increased calcium ion entry through the TRPC6 channel has been associated with the pathogenesis of heart and glomerular diseases, but its role in renal interstitial fibrosis is unknown. We studied this by deletion of Trpc6 in mice and found it decreased unilateral ureteral obstruction-induced interstitial fibrosis and blunted increased mRNA expression of fibrosis-related genes in the ureteral obstructed kidney relative to that in the kidney of wild-type mice. Administration of BTP2, a pyrazol derivative known to inhibit function of several TRPC channels, also ameliorated obstruction-induced renal fibrosis and gene expression in wild-type mice. BTP2 inhibited carbachol-activated TRPC3 and TRPC6 channel activities in HEK293 cells. Ureteral obstruction caused over a 10-fold increase in mRNA expression for TRPC3 as well as TRPC6 in the kidneys of obstructed relative to the sham-operated mice. The magnitude of protection against obstruction-induced fibrosis in Trpc3 and Trpc6 double knockout mice was not different from that in Trpc6 knockout mice. Klotho, a membrane and soluble protein predominantly produced in the kidney, is known to confer protection against renal fibrosis. Administration of soluble klotho significantly reduced obstruction-induced renal fibrosis in wild-type mice, but not in Trpc6 knockout mice, indicating that klotho and TRPC6 inhibition act in the same pathway to protect against obstruction-induced renal fibrosis. Thus klotho and TRPC6 may be pharmacologic targets for treating renal fibrosis.
| S-EPMC5357448 | biostudies-literature
Project description:NLRP3-mediated inflammation is closely related to the pathological progression of diabetic nephropathy (DN). DsbA-L, an antioxidant enzyme, plays a protective role in a variety of diseases by inhibiting ER stress and regulating metabolism. However, the relationship of DsbA-L with inflammation, especially the NLRP3 inflammasome, has not been examined. In this study, we note that activation of the NLRP3 inflammasome and exacerbated fibrosis were observed in the kidneys of diabetic DsbA-L-knockout mice and were accompanied by decreased phosphorylation of AMP-activated protein kinase (AMPK). Moreover, correlation analysis shows that the phosphorylation of AMPK was negatively correlated with NLRP3 expression and tubular damage. In addition, the decreased AMPK phosphorylation and NLRP3 activation induced by high glucose (HG) in HK-2 cells could be alleviated by the overexpression of DsbA-L. Interestingly, the protective effect of DsbA-L was eliminated after treatment with compound C, a well-known AMPK inhibitor. Our findings suggest that DsbA-L inhibits NLRP3 inflammasome activation by promoting the phosphorylation of AMPK.
| S-EPMC8120163 | biostudies-literature
Project description:BackgroundDiabetic nephropathy (DN) is a severe complication of diabetes mellitus (DM). Pancreas or islet transplantation has been reported to prevent the development of DN lesions and ameliorate or reverse existing glomerular lesions in animal models. Shortage of pancreas donor is a severe problem. Islets derived from stem cells may offer a potential solution to this problem.ObjectiveTo evaluate the effect of stem cell-derived islet transplantation on DN in a rat model of streptozotocin-induced DM.MethodsPancreatic progenitor cells were isolated from aborted fetuses of 8 weeks of gestation. And islets were prepared by suspension culture after a differentiation of progenitor cells in medium containing glucagon-like peptide-1 (Glp-1) and nicotinamide. Then islets were transplanted into the liver of diabetic rats via portal vein. Blood glucose, urinary volume, 24 h urinary protein and urinary albumin were measured once biweekly for 16 weeks. Graft survival was evaluated by monitoring human C-peptide level in rat sera and by immunohistochemical staining for human mitochondrial antigen and human C-peptide in liver tissue. The effect of progenitor-derived islets on filtration membrane was examined by electron microscopy and real-time polymerase chain reaction (PCR). Immunohistochemical staining, real-time PCR and western blot were employed for detecting fibronectin, protein kinase C beta (PKCβ), protein kinase A (PKA), inducible nitric oxide synthase (iNOS) and superoxide dismutase (SOD).ResultsIslet-like clusters derived from 8th gestational-week human fetal pancreatic progenitors survived in rat liver. And elevated serum level of human C-peptide was detected. Blood glucose, 24 h urinary protein and urinary albumin were lower in progenitor cell group than those in DN or insulin treatment group. Glomerular basement membrane thickness and fibronectin accumulation decreased significantly while podocytes improved morphologically in progenitor cell group. Furthermore, receptor of advanced glycation end products and PKCβ became down-regulated whereas PKA up-regulated by progenitor cell-derived islets. And iNOS rose while SOD declined.ConclusionsDN may be reversed by transplantation of human fetal pancreatic progenitor cell-derived islets. And fetal pancreatic progenitor cells offer potential resources for cell replacement therapy.
| S-EPMC5488369 | biostudies-literature
Project description:Atrasentan is a promising therapy for treating diabetic nephropathy (DN). Here we evaluated whether atrasentan down-regulated the miR-199b-5p expression, thereby increasing klotho and preventing renal tubular injury in DN. One-hundred patients with type 2 diabetes mellitus (T2DM) and 40 healthy subjects were included. A DN mice model was established by an injection of streptozotocin (STZ). Human renal proximal tubular epithelial HK-2 cells were exposed to high glucose (20 mmol/L). Treated the mice and HK-2 cells with atrasentan, and we then investigated whether and how miR-199b-5p and Klotho were involved in preventing renal tubular injury in DN. In patients, the serum miR-199b-5p level increased and the klotho concentration decreased in accordance with elevated albuminuria. Atrasentan down-regulated miR-199b-5p and up-regulated klotho of the DN mice and HK-2 cells exposed to high glucose. High glucose promoted the binding of histone H3 to the miR-199b-5p promoter, and atrasentan canceled this effect. MiR-199b-5p targeted the 3' UTR of klotho. Overexpression of miR-199b-5p canceled the effects of atrasentan on klotho expression and apoptosis of renal tubular cells in both in vivo and in vitro. The increased serum klotho, mediated by miR-199b-5p, is a possible mechanism by which atrasentan prevents renal tubular injury in DN.
| S-EPMC4728478 | biostudies-literature
Project description:The present study aimed to investigate whether klotho gene delivery attenuated renal hypertrophy and fibrosis in streptozotocin-induced diabetic rats. A recombinant adeno-associated virus (rAAV) carrying mouse klotho full-length cDNA (rAAV.mKL), was constructed for in vivo investigation of klotho expression. Diabetes was induced in rats by a single tail vein injection of 60 mg/kg streptozotocin. Subsequently, the diabetic rats received an intravenous injection of rAAV.mKL, rAAV.green fluorescent protein (GFP) or phosphate-buffered saline (PBS). The Sprague-Dawley rat group received PBS and served as the control group. After 12 weeks, all the rats were sacrificed and ELISA, immunohistochemical and histological analyses, fluorescence microscopy, semi-quantitative reverse transcription-polymerase chain reaction and western blottin were performed. A single dose of rAAV.mKL was found to prevent the progression of renal hypertrophy and fibrosis for at least 12 weeks (duration of study). Klotho expression was suppressed in the diabetic rats, but was increased by rAAV.mKL delivery. rAAV.mKL significantly suppressed diabetes-induced renal hypertrophy and histopathological changes, reduced renal collagen fiber generation and decreased kidney hypertrophy index. In addition, rAAV.mKL decreased the protein expression levels of fibronectin and vimentin, while it downregulated the mRNA expression and activity of Rho-associated coiled-coil kinase (ROCK)I in the kidneys of the diabetic rats. These results indicated that klotho gene delivery ameliorated renal hypertrophy and fibrosis in diabetic rats, possibly by suppressing the ROCK signaling pathway. This may offer a novel approach for the long-term control and renoprotection of diabetes.
| S-EPMC4438939 | biostudies-literature
Project description:Progressive reduction of SnoN is associated with gradual elevation of TGF-β1 during diabetic nephropathy progression, suggesting SnoN to be a possible mediator of TGF-β1 signaling, with potential therapeutic benefits against TGF- β1 -induced renal fibrosis. To characterize SnoN for its role in renal fibrosis, we assessed SnoN expression patterns in response to high glucose stress, and evaluated the effects of upregulating SnoN on renal fibrosis. High glucose stress induced significantly elevated SnoN, TGF-β1, and Arkadia transcription; however, significantly reduced SnoN protein levels were observed under these conditions. Upregulating the SnoN protein was achieved by Arkadia knockdown, which resulted in inhibited high glucose-induced epithelial-mesenchymal transition (EMT) in renal tubular cells, the onset phase of renal fibrosis. Alternatively, EMT was suppressed by dominantly expressed exogenous SnoN without interfering with TGF-β1. Overall, renal SnoN upregulation ameliorates renal fibrosis by relieving high glucose-induced EMT; these findings support a translational approach targeting SnoN for the treatment of diabetic nephropathy.
| S-EPMC5370123 | biostudies-literature
Project description:The antioxidant function of Klotho is well-documented as a regulatory factor implicated in countering the aging process. This study investigated whether ginseng upregulates Klotho and its antiaging signaling in a setting of calcineurin inhibitor-induced oxidative stress. Although tacrolimus treatment reduced Klotho level in the serum and kidney, ginseng treatment was found to reverse the levels. Tacrolimus-induced oxidative stress was reduced by ginseng treatment, with functional and histological improvements. Effect of ginseng on Klotho-induced manganese superoxide dismutase signaling pathway during tacrolimus treatment in mice revealed that ginseng suppressed phosphatidylinositol 3-kinase/serine-threonine kinase Akt-mediated phosphorylation of forkhead box protein O3a and promoted the binding of forkhead box protein O3a to manganese superoxide dismutase promoter. In the mitochondria, ginseng reduced mitochondrial reactive oxygen species production, mitochondrial membrane potential, and oxygen consumption rate, whereas blocking phosphatidylinositol 3-kinase activity with LY294002 enhanced them. These findings together suggested that ginseng attenuated tacrolimus-induced oxidative stress via signaling between Klotho and the phosphatidylinositol 3-kinase/serine-threonine kinase Akt/forkhead box protein O3a-related antioxidant pathway.
| S-EPMC6710054 | biostudies-literature
Project description:The expression of the renoprotective antiaging gene Klotho is decreased in uremia. Recent studies suggest that Klotho may be a tumor suppressor, and its expression may be repressed by DNA hypermethylation in cancer cells. Here we investigated the effects and possible mechanisms by which Klotho expression is regulated during uremia in uninephrectomized B-6 mice given the uremic toxins indoxyl sulfate or p-cresyl sulfate. Cultured human renal tubular HK2 cells treated with these toxins were used as an in vitro model. Injections of indoxyl sulfate or p-cresyl sulfate increased their serum concentrations, kidney fibrosis, CpG hypermethylation of the Klotho gene, and decreased Klotho expression in renal tubules of these mice. The expression of DNA methyltransferases 1, 3a, and 3b isoforms in HK2 cells treated with indoxyl sulfate or p-cresyl sulfate was significantly increased. Specific inhibition of DNA methyltransferase isoform 1 by 5-aza-2'-deoxycytidine caused demethylation of the Klotho gene and increased Klotho expression in vitro. Thus, inhibition of Klotho gene expression by uremic toxins correlates with gene hypermethylation, suggesting that epigenetic modification of specific genes by uremic toxins may be an important pathological mechanism of disease.
| S-EPMC3306006 | biostudies-literature