scholarly journals Gigantol has Protective Effects against High Glucose-Evoked Nephrotoxicity in Mouse Glomerulus Mesangial Cells by Suppressing ROS/MAPK/NF-κB Signaling Pathways

Molecules ◽  
2018 ◽  
Vol 24 (1) ◽  
pp. 80 ◽  
Author(s):  
Mei-Fen Chen ◽  
Shorong-Shii Liou ◽  
Tang-Yao Hong ◽  
Shung-Te Kao ◽  
I-Min Liu

Gigantol is a bibenzyl compound derived from several medicinal orchids. This biologically active compound has shown promising therapeutic potential against diabetic cataracts, but whether this compound exerts beneficial effects on the other diabetic microvascular complications remains unclear. This study was carried out to examine effects of gigantol on high glucose-induced renal cell injury in cultured mouse kidney mesangial cells (MES-13). MES-13 cells were pretreated with gigantol (1, 5, 10 or 20 μmol/L) for 1 h followed by further exposure to high (33.3 mmol/L) glucose for 48 h. Gigantol concentration dependently enhanced cell viability followed by high glucose treatment in MES-13 cells. High glucose induced reactive oxygen species (ROS) generation, malondialdehyde production and glutathione deficiency were recoved in MES-13 cells pretreated with gigantol. High glucose triggered cell apoptosis via the the loss of mitochondrial membrane potential, depletion of adenosine triphosphate, upregulation of caspases 9 and 3, enhancement of cytochrome c release, and subsequent interruption of the Bax/Bcl-2 balance. These detrimental effects were ameliorated by gigantol. High glucose also induced activation of JNK, p38 mitogen-activated protein kinase (MAPK) and nuclear factor-κB (NF-κB) in MES-13 cells, which were blocked by gigantol. The results suggest that treatment MES-13 cells with gigantol halts high glucose-induced renal dysfunction through the suppression of the ROS/MAPK/NF-κB signaling pathways. Our data are of value to the understanding the mechanism for gigantol, and would benefit the study of drug development or food supplement for diabetes and nephropathy.

Endocrinology ◽  
2010 ◽  
Vol 151 (7) ◽  
pp. 3317-3325 ◽  
Author(s):  
Jiqian Huang ◽  
Helmy M. Siragy

Renal (pro)renin receptor (PRR) expression is increased in diabetes. The exact mechanisms involved in this process are not well established. We hypothesized that high glucose up-regulates PRR through protein kinase C (PKC)-Raf-ERK and PKC-c-Jun N-terminal kinase (JNK)-c-Jun signaling pathways. Rat mesangial cells exposed to 30 mmd-glucose demonstrated significant increase in PRR mRNA and protein expression, intracellular phosphorylation of Raf-1 (Y340/341), ERK, JNK, nuclear factor-κB (NF-κB) p65 (S536) and c-Jun (S63). By chromatin immunoprecipitation assay and EMSA, high glucose induced more functional NF-κB and activator protein (AP)-1 dimers bound to corresponding cis-regulatory elements in the predicted PRR promoter to up-regulate PRR transcription. Conventional and novel PKC inhibitors Chelerythrine and Rottlerin, Raf-1 inhibitor GW5074, MEK1/2 inhibitor U0126, JNK inhibitor SP600125, NF-κB inhibitor Quinazoline, and AP-1 inhibitor Curcumin, respectively, attenuated glucose-induced PRR up-regulation. Chelerythrine and Rottlerin also inhibited glucose-induced phosphorylation of Raf-1 (Y340/341), ERK1/2, JNK, NF-κB p65 (S536), and c-Jun (S63). GW5074 and U0126 inhibited the phosphorylation of ERK1/2 and NF-κB p65 (S536). SP600125 inhibited phosphorylation of NF-κB p65 (S536) and c-Jun (S63). We conclude that high glucose up-regulates the expression of PRR through mechanisms dependent on both PKC-Raf-ERK and PKC-JNK-c-Jun signaling pathways. NF-κB and AP-1 are involved in high-glucose-induced PRR up-regulation in rat mesangial cells.


2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Jie Yun ◽  
Jinyu Ren ◽  
Yufei Liu ◽  
Lijuan Dai ◽  
Liqun Song ◽  
...  

Abstract Background Circular RNAs (circRNAs) have been considered as pivotal biomarkers in Diabetic nephropathy (DN). CircRNA ARP2 actin-related protein 2 homolog (circ-ACTR2) could promote the HG-induced cell injury in DN. However, how circ-ACTR2 acts in DN is still unclear. This study aimed to explore the molecular mechanism of circ-ACTR2 in DN progression, intending to provide support for the diagnostic and therapeutic potentials of circ-ACTR2 in DN. Methods RNA expression analysis was conducted by the quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Cell growth was measured via Cell Counting Kit-8 and EdU assays. Inflammatory response was assessed by Enzyme-linked immunosorbent assay. The protein detection was performed via western blot. Oxidative stress was evaluated by the commercial kits. The molecular interaction was affirmed through dual-luciferase reporter and RNA immunoprecipitation assays. Results Circ-ACTR2 level was upregulated in DN samples and high glucose (HG)-treated human renal mesangial cells (HRMCs). Silencing the circ-ACTR2 expression partly abolished the HG-induced cell proliferation, inflammation and extracellular matrix accumulation and oxidative stress in HRMCs. Circ-ACTR2 was confirmed as a sponge for miR-205-5p. Circ-ACTR2 regulated the effects of HG on HRMCs by targeting miR-205-5p. MiR-205-5p directly targeted high-mobility group AT-hook 2 (HMGA2), and HMGA2 downregulation also protected against cell injury in HG-treated HRMCs. HG-mediated cell dysfunction was repressed by miR-205-5p/HMGA2 axis. Moreover, circ-ACTR2 increased the expression of HMGA2 through the sponge effect on miR-205-5p in HG-treated HRMCs. Conclusion All data have manifested that circ-ACTR2 contributed to the HG-induced DN progression in HRMCs by the mediation of miR-205-5p/HMGA2 axis.


Biomolecules ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 348 ◽  
Author(s):  
Ravindran ◽  
Pasha ◽  
Agouni ◽  
Munusamy

Diabetic nephropathy (DN) is the most common cause of chronic kidney disease worldwide. Activation of signaling pathways such as the mammalian target of rapamycin (mTOR), extracellular signal-regulated kinases (ERK), endoplasmic reticulum (ER) stress, transforming growth factor-beta (TGF-β), and epithelial-mesenchymal transition (EMT), are thought to play a significant role in the etiology of DN. Microparticles (MPs), the small membrane vesicles containing bioactive signals shed by cells upon activation or during apoptosis, are elevated in diabetes and were identified as biomarkers in DN. However, their exact role in the pathophysiology of DN remains unclear. Here, we examined the effect of MPs shed from renal proximal tubular cells (RPTCs) exposed to high glucose conditions on naïve RPTCs in vitro. Our results showed significant increases in the levels of phosphorylated forms of 4E-binding protein 1 and ERK1/2 (the downstream targets of mTOR and ERK pathways), phosphorylated-eIF2α (an ER stress marker), alpha smooth muscle actin (an EMT marker), and phosphorylated-SMAD2 and nuclear translocation of SMAD4 (markers of TGF-β signaling). Together, our findings indicate that MPs activate key signaling pathways in RPTCs under high glucose conditions. Pharmacological interventions to inhibit shedding of MPs from RPTCs might serve as an effective strategy to prevent the progression of DN.


2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Kaifeng Li ◽  
Mengen Zhai ◽  
Liqing Jiang ◽  
Fan Song ◽  
Bin Zhang ◽  
...  

Hyperglycemia-induced oxidative stress and fibrosis play a crucial role in the development of diabetic cardiomyopathy (DCM). Tetrahydrocurcumin (THC), a major bioactive metabolite of natural antioxidant curcumin, is reported to exert even more effective antioxidative and superior antifibrotic properties as well as anti-inflammatory and antidiabetic abilities. This study was designed to investigate the potential protective effects of THC on experimental DCM and its underlying mechanisms, pointing to the role of high glucose-induced oxidative stress and interrelated fibrosis. In STZ-induced diabetic mice, oral administration of THC (120 mg/kg/d) for 12 weeks significantly improved the cardiac function and ameliorated myocardial fibrosis and cardiac hypertrophy, accompanied by reduced reactive oxygen species (ROS) generation. Mechanically, THC administration remarkably increased the expression of the SIRT1 signaling pathway both in vitro and in vivo, further evidenced by decreased downstream molecule Ac-SOD2 and enhanced deacetylated production SOD2, which finally strengthened antioxidative stress capacity proven by repaired activities of SOD and GSH-Px and reduced MDA production. Additionally, THC treatment accomplished its antifibrotic effect by depressing the ROS-induced TGFβ1/Smad3 signaling pathway followed by reduced expression of cardiac fibrotic markers α-SMA, collagen I, and collagen III. Collectively, these finds demonstrated the therapeutic potential of THC treatment to alleviate DCM mainly by attenuating hyperglycemia-induced oxidative stress and fibrosis via activating the SIRT1 pathway.


2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Zhigui Wu ◽  
Wenxian Yin ◽  
Mengqi Sun ◽  
Yuankai Si ◽  
Xiaoxiao Wu ◽  
...  

Objective. To explore the role and mechanism of BKCa in diabetic kidney disease. Methods. Rat mesangial cells (MCs) HBZY-1 were cultured with high glucose to simulate the high-glucose environment of diabetic kidney disease in vivo. The effects of large conductance calcium-activated potassium channel (BKCa) on proliferation, migration, and apoptosis of HBZY-1 cells were observed. The contents of transforming growth factor beta 1 (TGF-β1), Smad2/3, collagen IV (Col IV), and fibronectin (FN) in the extracellular matrix were also observed. Results. High glucose significantly damaged HBZY-1 cells, which enhanced the ability of cell proliferation, migration, and apoptosis, and increased the secretion of Col IV and FN. Inhibition of BKCa and TGF-β1/Smad2/3 signaling pathways can inhibit the proliferation, migration, and apoptosis of HBZY-1 cells and suppress the secretion of Col IV and FN. The effect of excitation is the opposite. Conclusions. BKCa regulates mesangial cell proliferation, migration, apoptosis, and secretion of Col IV and FN and is associated with TGF-β1/Smad2/3 signaling pathway.


2011 ◽  
Vol 301 (4) ◽  
pp. E713-E726 ◽  
Author(s):  
Howard Goldberg ◽  
Catharine Whiteside ◽  
I. George Fantus

Hyperglycemia augments flux through the hexosamine biosynthetic pathway and subsequent O-linkage of single β- N-acetyl-d-glucosamine moieties to serine and threonine residues on cytoplasmic and nuclear proteins ( O-GlcNAcylation). Perturbations in this posttranslational modification have been proposed to promote glomerular matrix accumulation in diabetic nephropathy, but clear evidence and mechanism are lacking. We tested the hypothesis that O-GlcNAcylation enhances profibrotic signaling in rat mesangial cells. An adenovirus expressing shRNA directed against O-GlcNAc transferase (OGT) markedly reduced basal and high-glucose-stimulated O-GlcNAcylation. Interestingly, O-GlcNAc depletion prevented high-glucose-induced p38 mitogen-activated protein kinase (MAPK) and c-Jun NH2-terminal kinase phosphorylation. Downstream of p38, O-GlcNAc controlled the expression of plasminogen activator inhibitor-1, fibronectin, and transforming growth factor-β, important factors in matrix accumulation in diabetic nephropathy. Treating mesangial cells with thiamet-G, a highly selective inhibitor of O-GlcNAc-specific hexosaminidase ( O-GlcNAcase), increased O-GlcNAcylation and p38 phosphorylation. The high-glucose-stimulated kinase activity of apoptosis signal-regulating kinase 1 (ASK1), an upstream MAPK kinase kinase for p38 that is negatively regulated by Akt, was inhibited by OGT shRNA. Akt Thr308 and Ser473 phosphorylation were enhanced following OGT shRNA expression in high-glucose-exposed mesangial cells, but high-glucose-induced p38 phosphorylation was not attenuated by OGT shRNA in cells pretreated with the phosphatidylinositol 3-kinase inhibitor LY-294002. OGT shRNA also reduced high-glucose-stimulated reactive oxygen species (ROS) formation. In contrast, diminished O-GlcNAcylation caused elevated ERK phosphorylation and PKCδ membrane translocation. Thus, O-GlcNAcylation is coupled to profibrotic p38 MAPK signaling by high glucose in part through Akt and possibly through ROS.


2020 ◽  
Vol 134 (1) ◽  
pp. 75-85 ◽  
Author(s):  
Jianyong Yin ◽  
Xuanchen Liu ◽  
Ting Zhao ◽  
Rulian Liang ◽  
Rui Wu ◽  
...  

Abstract Renalase, a recently discovered secreted flavoprotein, exerts anti-apoptotic and anti-inflammatory effects against renal injury in acute and chronic animal models. However, whether Renalase elicits similar effects in the development of diabetic nephropathy (DN) remains unclear. The studies presented here tested the hypothesis that Renalase may play a key role in the development of DN and may have therapeutic potential for DN. Renalase expression was measured in human kidney biopsies with DN and in kidneys of db/db mice. The role of Renalase in the development of DN was examined using a genetically engineered mouse model: Renalase knockout mice with db/db background. The renoprotective effects of Renalase in DN was evaluated in db/db mice with Renalase overexpression. In addition, the effects of Renalase on high glucose-induced mesangial cells were investigated. Renalase was down-regulated in human diabetic kidneys and in kidneys of db/db mice compared with healthy controls or db/m mice. Renalase homozygous knockout increased arterial blood pressure significantly in db/db mice while heterozygous knockout did not. Renalase heterozygous knockout resulted in elevated albuminuria and increased renal mesangial expansion in db/db mice. Mesangial hypertrophy, renal inflammation, and pathological injury in diabetic Renalase heterozygous knockout mice were significantly exacerbated compared with wild-type littermates. Moreover, Renalase overexpression significantly ameliorated renal injury in db/db mice. Mechanistically, Renalase attenuated high glucose-induced profibrotic gene expression and p21 expression through inhibiting extracellular regulated protein kinases (ERK1/2). The present study suggested that Renalase protected against the progression of DN and might be a novel therapeutic target for the treatment of DN.


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