scholarly journals SENP1-Mediated Desumoylation of DBC1 Inhibits Apoptosis Induced by High Glucose in Bovine Retinal Pericytes

2016 ◽  
Vol 2016 ◽  
pp. 1-11
Author(s):  
Jian Gao ◽  
Xia Chen ◽  
Qing Gu ◽  
Xiaoxiao Liu ◽  
Xun Xu
Keyword(s):  
Diabetic Retinopathy ◽  
High Glucose ◽  
Molecular Mechanisms ◽  
Characteristic Change ◽  
High Concentration ◽  
Retinal Pericytes ◽  
Specific Protease ◽  
Induced Apoptosis ◽  
Pericyte Loss

Pericyte loss is an early characteristic change in diabetic retinopathy, but its precise molecular mechanisms have not been elucidated. This study investigated the role of SENP1 in pericyte loss in diabetic retinopathy. We demonstrated that a high concentration of glucose inhibited the expression of the Sentrin/SUMO-specific protease 1 (SENP1), which resulted in an increase in DBC1 sumoylation in bovine retinal pericytes (BRPCs). Furthermore, SENP1 overexpression attenuated hyperemia-induced apoptosis of BPRCs, and SENP1 knockdown aggravated this effect. We also provide evidence that DBC1 sumoylation/desumoylation is involved in the SENP1-regulated apoptosis of BRPCs under high glucose conditions. Understanding the role of SENP1 in the pathogenesis of high glucose induced pericyte loss could help elucidate important targets for future pharmacological interventions.

MiR-126 targets IL-17A to enhance proliferation and inhibit apoptosis in high-glucose-induced human retinal endothelial cells

2020 ◽  
Vol 98 (2) ◽  
pp. 277-283 ◽  
Author(s):  
Xiujuan Chen ◽  
Xuequn Yu ◽  
Xinxiang Li ◽  
Li Li ◽  
Fang Li ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
High Glucose ◽  
Molecular Mechanisms ◽  
Caspase 3 ◽  
Vision Loss ◽  
Retinal Endothelial Cells ◽  
Interleukin 17A ◽  
Novel Target ◽  
Induced Apoptosis

Diabetic retinopathy (DR) is a common complication of diabetes mellitus (DM), which results in vision loss. This study explored the role of miR-126 in high-glucose-induced human retinal endothelial cells (HRECs) and its underlying molecular mechanisms. The results showed that the expression levels of miR-126 and interleukin-17A (IL-17A) in high-glucose-induced HRECs were downregulated and upregulated, respectively. Functionally, overexpression of miR-126 promoted proliferation and suppressed apoptosis in high-glucose-induced HRECs, while IL-17A reversed the effects induced by miR-126. However, overexpression of IL-17A inhibited the proliferation and induced apoptosis, while knockdown of IL-17A accelerated the proliferation and repressed apoptosis. In addition, miR-126 repressed the expression of IL-17A, Bax, and caspase-3, while promoting the expression of survivin and phosphorylation of PI3K and AKT; restoration of IL-17A rescued these effects. Furthermore, IL-17A was identified as a target of miR-126. This indicates that miR-126 enhances proliferation and inhibits apoptosis in high-glucose-induced HRECs by activating the PI3K–AKT pathway, increasing survivin levels, and decreasing Bax and caspase-3 expression by targeting IL-17A, suggesting that miR-126 could be a novel target for preventing DR.

scholarly journals O-Linked β-N-acetylglucosamine (O-GlcNAc) modification: a new pathway to decode pathogenesis of diabetic retinopathy

2018 ◽  
Vol 132 (2) ◽  
pp. 185-198 ◽  
Author(s):  
Zafer Gurel ◽  
Nader Sheibani
Keyword(s):  
Diabetic Retinopathy ◽  
High Glucose ◽  
Biosynthetic Pathway ◽  
Amino Acid Residues ◽  
Therapeutic Approaches ◽  
Hexosamine Biosynthetic Pathway ◽  
Retinal Pericytes ◽  
A Cell ◽  
Insight Into

The incidence of diabetes continues to rise among all ages and ethnic groups worldwide. Diabetic retinopathy (DR) is a complication of diabetes that affects the retinal neurovasculature causing serious vision problems, including blindness. Its pathogenesis and severity is directly linked to the chronic exposure to high glucose conditions. No treatments are currently available to stop the development and progression of DR. To develop new and effective therapeutic approaches, it is critical to better understand how hyperglycemia contributes to the pathogenesis of DR at the cellular and molecular levels. We propose alterations in O-GlcNAc modification of target proteins during diabetes contribute to the development and progression of DR. The O-GlcNAc modification is regulated through hexosamine biosynthetic pathway. We showed this pathway is differentially activated in various retinal vascular cells under high glucose conditions perhaps due to their selective metabolic activity. O-GlcNAc modification can alter protein stability, activity, interactions, and localization. By targeting the same amino acid residues (serine and threonine) as phosphorylation, O-GlcNAc modification can either compete or cooperate with phosphorylation. Here we will summarize the effects of hyperglycemia-induced O-GlcNAc modification on the retinal neurovasculature in a cell-specific manner, providing new insight into the role of O-GlcNAc modification in early loss of retinal pericytes and the pathogenesis of DR.

scholarly journals High glucose induces Nox4 expression and podocyte apoptosis through the Smad3/ezrin/PKA pathway

Biology Open ◽  
2020 ◽  
pp. bio.055012
Author(s):  
Wanxu Guo ◽  
Hang Gao ◽  
Wei Pan ◽  
Panapn Yu ◽  
Guanghua Che
Keyword(s):  
High Glucose ◽  
Molecular Mechanisms ◽  
Ros Generation ◽  
Intracellular Camp ◽  
Ros Production ◽  
Intracellular Ros ◽  
Induced Apoptosis ◽  
Pka Pathway ◽  
Major Target

Podocyte is the major target in proteinuric kidney disease such as diabetic nephropathy. The underlying molecular mechanisms by which high glucose (HG) results in podocyte damage remain unclear. This study investigated the regulatory role of Smad3, ezrin, and protein kinase A (PKA) in NADPH oxidase (Nox4) expression, reactive oxidative species (ROS) production, and apoptosis in HG-treated podocytes. Human podocyte cell line was cultured and differentiated, then treated with 30 mM HG. Apoptosis and intracellular ROS level was assessed using TUNEL and DCF assay, respectively. Expressions of Nox4, phospho-Smad3Ser423/425, phospho-PKAThr197, and phospho-ezrinThr567 were evaluated using Western blotting. ELISA was used to quantify intracellular cAMP concentration and PKA activity. Knockdown assay was used to inhibit the expressions of Smad3, Nox4, and ezrin by lentiviral shRNA. In HG-treated podocytes, the level of phospho-Smad3Ser423/425 and phospho-ezrinThr567 was increased significantly, which was accompanied by the reduction of cAMP and phospho-PKAThr197. HG-induced apoptosis was significantly prevented by the Smad3 inhibitor SIS3 or shRNA-Smad3. In podocytes expressing shRNA-ezrin or shRNA-Nox4, apoptosis was remarkably mitigated following HG treatment. HG-induced upregulation of phospho-ezrinThr567 and downregulation of phospho-PKAThr197 was significantly prevented by SIS3, shRNA-ezrin or shRNA-Smad3. Forskolin, a PKA activator, significantly inhibited HG-mediated upregulation of Nox4 expression, ROS generation, and apoptosis. Additionally, an increase in the ROS level was prohibited in HG-treated podocytes with the knockdown of Nox4, Smad3, or ezrin. Taken together, our findings provided evidence that Smad3-mediated ezrin activation upregulates Nox4 expression and ROS production, by suppressing PKA activity, which may at least in part contribute to HG-induced podocyte apoptosis.

Role of the Polyol Pathway in High Glucose–Induced Apoptosis of Retinal Pericytes and Proliferation of Endothelial Cells

2008 ◽  
Vol 49 (7) ◽  
pp. 3216 ◽  
Author(s):  
Yoshihiro Takamura ◽  
Takeshi Tomomatsu ◽  
Eri Kubo ◽  
Syousai Tsuzuki ◽  
Yoshio Akagi
Keyword(s):  
Endothelial Cells ◽  
High Glucose ◽  
Polyol Pathway ◽  
Retinal Pericytes ◽  
Induced Apoptosis

scholarly journals The p53/miR-34a/SIRT1 Positive Feedback Loop in Quercetin-Induced Apoptosis

2015 ◽  
Vol 35 (6) ◽  
pp. 2192-2202 ◽  
Author(s):  
Guohua Lou ◽  
Yanning Liu ◽  
Shanshan Wu ◽  
Jihua Xue ◽  
Fan Yang ◽  
...  
Keyword(s):  
Cell Apoptosis ◽  
Feedback Loop ◽  
Molecular Mechanisms ◽  
Rt Pcr ◽  
Cycle Arrest ◽  
Anticancer Effects ◽  
Huh7 Cells ◽  
Mirnas Expression ◽  
Induced Apoptosis

Background: The anti-tumor effects of quercetin have been reported, but the underlying molecular mechanisms remain to be elucidated. The aim of present study was to explore the role of miRNA in the anticancer effects of quercetin. Methods: The differential miRNAs expression between the HepG2 and Huh7 cells treated by quercetin were detected by microarray. The xCELLigence, Flow cytometry, RT-PCR and Western blot were used to analyze the cell proliferation, cell apoptosis, cell cycle arrest, anti-tumor genes, and protein expression. Results: miR-34a was up-regulated in HepG2 cells treated by quercetin exhibiting wild-type p53. When inhibiting the miR-34a, the sensitivity of the cells to quercetin decreased and the expression of the SIRT1 was up-regulated, but the acetylation of p53 and the expression of some genes related to p53 down-regulated. Conclusion: miR-34a plays an important role in the anti-tumor effects of querctin in HCC, miR-34a may be a tiemolecule between the p53 and SIRT1 and is composed of a p53/miR-34a/SIRT1 signal feedback loop, which could enhance apoptosis signal and significantly promote cell apoptosis.

scholarly journals Tribbles Homolog 3 Mediates the Development and Progression of Diabetic Retinopathy

2021 ◽  
Author(s):  
Priyamvada M. Pitale ◽  
Irina V. Saltykova ◽  
Yvonne Adu-Agyeiwaah ◽  
Sergio Li Calzi ◽  
Takashi Satoh ◽  
...  
Keyword(s):  
Diabetic Retinopathy ◽  
Functional Restoration ◽  
Dramatic Reduction ◽  
Vegf Expression ◽  
Inflammatory Gene Expression ◽  
Hypoxic Conditions ◽  
Molecular Events ◽  
Glucose Flux ◽  
Pericyte Loss

The current understanding of molecular pathogenesis of diabetic retinopathy does not provide a mechanistic link between early molecular changes and the subsequent progression of the disease. In this study, we found that human diabetic retinas overexpressed TRIB3 and investigated the role of TRIB3 in diabetic retinal pathobiology in mice. We discovered that TRIB3 controlled major molecular events in early diabetic retinas via HIF1α-mediated regulation of retinal glucose flux, reprograming cellular metabolism, and governing inflammatory gene expression. These early molecular events further defined the development of neurovascular deficit observed in mice with diabetic retinopathy. TRIB3 ablation in STZ-induced mouse model led to significant RGC survival and functional restoration accompanied by a dramatic reduction in pericyte loss and acellular capillary formation. Under hypoxic conditions, TRIB3 contributed to advanced proliferative stages by significant upregulation of GFAP and VEGF expression, thus controlling gliosis and aberrant vascularization in OIR mouse retinas. Overall, our data reveal that TRIB3 is a master regulator of diabetic retinal pathophysiology that may accelerate the onset and progression of diabetic retinopathy to proliferative stages in humans and present TRIB3 as a potentially novel therapeutic target for diabetic retinopathy.

scholarly journals Hepcidin links gluco-toxicity to pancreatic beta cell dysfunction by inhibiting Pdx-1 expression

2017 ◽  
Vol 6 (3) ◽  
pp. 121-128 ◽  
Author(s):  
Xuhua Mao ◽  
Hucheng Chen ◽  
Junmin Tang ◽  
Liangliang Wang ◽  
Tingting Shu
Keyword(s):  
High Glucose ◽  
Molecular Mechanisms ◽  
Cell Function ◽  
Pancreatic Beta Cell ◽  
Mrna Levels ◽  
Β Cell ◽  
Min6 Cells ◽  
Hepcidin Expression ◽  
Insulin Synthesis

Objective Gluco-toxicity is a term used to convey the detrimental effect of hyperglycemia on β-cell function through impaired insulin synthesis. Although it is known that the expression and activity of several key insulin transcription regulators is inhibited, other molecular mechanisms that mediate gluco-toxicity are poorly defined. Our objective was to explore the role of hepcidin in β-cell gluco-toxicity. Design We first confirmed that high glucose levels inhibited hepcidin expression in the mouse insulinoma cell line, MIN6. The downregulation of hepcidin decreased Pdx-1 expression, which reduced insulin synthesis. Methods MIN6 cells were exposed to high glucose concentrations (33.3 mmol/L). Glucose-stimulated insulin secretion (GSIS) and serum hepcidin levels were measured by ELISA. The mRNA levels of insulin1, insulin2, Pdx-1 and hepcidin were measured by real-time polymerase chain reaction. Western blot analysis was used to detect the changes in PDX-1 expression. Transient overexpression with hepcidin was used to reverse the downregulation of Pdx-1 and insulin synthesis induced by gluco-toxicity. Results Exposure of MIN6 cells to high glucose significantly decreased GSIS and inhibited insulin synthesis as well as Pdx-1 transcriptional activity and expression at both the mRNA and protein levels. High glucose also decreased hepcidin expression and secretion. Hepcidin overexpression in MIN6 cells partially reversed the gluco-toxicity-induced downregulation of Pdx-1 and insulin expression and improved GSIS. The restoration of insulin synthesis by transfection of a hepcidin overexpression plasmid confirmed the role of hepcidin in mediating the gluco-toxic inhibition of insulin synthesis. Conclusions Our observations suggest that hepcidin is associated with gluco-toxicity-reduced pancreatic β-cell insulin synthesis in type 2 diabetes by inhibiting Pdx-1 expression.

scholarly journals Proteasome Activators, PA28α and PA28β, Govern Development of Microvascular Injury in Diabetic Nephropathy and Retinopathy

2016 ◽  
Vol 2016 ◽  
pp. 1-13 ◽  
Author(s):  
Saeed Yadranji Aghdam ◽  
Ali Mahmoudpour
Keyword(s):  
Diabetic Nephropathy ◽  
High Glucose ◽  
Molecular Mechanisms ◽  
Mesangial Cells ◽  
Diabetic Mice ◽  
Double Knockout ◽  
Monocyte Chemoattractant Protein 1 ◽  
Microvascular Injury ◽  
Retinal Pericytes ◽  
Diabetes Model

Diabetic nephropathy (DN) and diabetic retinopathy (DR) are major complications of type 1 and type 2 diabetes. DN and DR are mainly caused by injury to the perivascular supporting cells, the mesangial cells within the glomerulus, and the pericytes in the retina. The genes and molecular mechanisms predisposing retinal and glomerular pericytes to diabetic injury are poorly characterized. In this study, the genetic deletion of proteasome activator genes, PA28α and PA28β genes, protected the diabetic mice in the experimental STZ-induced diabetes model against renal injury and retinal microvascular injury and prolonged their survival compared with wild type STZ diabetic mice. The improved wellbeing and reduced renal damage was associated with diminished expression of Osteopontin (OPN) and Monocyte Chemoattractant Protein-1 (MCP-1) in the glomeruli of STZ-injected PA28α/PA28β double knockout (Pa28αβDKO) mice and also in cultured mesangial cells and retinal pericytes isolated from Pa28αβDKO mice that were grown in high glucose. The mesangial PA28-mediated expression of OPN under high glucose conditions was suppressed by peptides capable of inhibiting the binding of PA28 to the 20S proteasome. Collectively, our findings demonstrate that diabetic hyperglycemia promotes PA28-mediated alteration of proteasome activity in vulnerable perivascular cells resulting in microvascular injury and development of DN and DR.

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