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.

scholarly journals Oxidative stress-induced JNK activation contributes to proinflammatory phenotype of aging diabetic mesangial cells

2009 ◽  
Vol 297 (6) ◽  
pp. F1622-F1631 ◽  
Author(s):  
Jin Wu ◽  
Changlin Mei ◽  
Helen Vlassara ◽  
Gary E. Striker ◽  
Feng Zheng
Keyword(s):  
Oxidative Stress ◽  
Diabetic Nephropathy ◽  
Mesangial Cells ◽  
Mitogen Activated Protein Kinase ◽  
Phenotypic Change ◽  
Diabetic Mice ◽  
Monocyte Chemoattractant Protein 1 ◽  
Inflammatory Lesions ◽  
Jnk Activation

Chronic inflammation and increased oxidative stress (OS) play an important role in diabetic nephropathy progression. Herein, we show that mesangial cells from streptozotocin-induced aging diabetic mice, a model of progressive diabetic nephropathy, exhibited increased OS and a proinflammatory phenotype characterized by elevated chemokines and ICAM-1 expression. This phenotypic change was consistent with the extensive inflammatory lesions present in aging diabetic kidneys and was not found in mesangial cells from old and young controls or young diabetic mice. Activation of the c-Jun NH2-terminal kinase (JNK) pathway was a likely contributor to the proinflammatory phenotype of aging diabetic mesangial cells since 1) phosphorylated JNK levels and JNK kinase activity were increased in these cells, 2) suppression of JNK significantly decreased monocyte chemoattractant protein-1 (MCP-1) production in these cells, and 3) activation of JNK in normal mesangial cells induced inflammation. Elevated OS in aging diabetic mesangial cells may be a cause of JNK activation and inflammation, because antioxidant treatment decreased JNK phosphorylation and MCP-1 production. Additionally, decreased expression of mitogen-activated protein kinase phosphatase 5 (MKP5) may also contribute to increased JNK and inflammation in aging diabetic mesangial cells since overexpression of MKP5 in these cells normalized phosphorylated JNK levels and reversed the proinflammatory phenotype. Moreover, knocking down of MKP5 expression in old control mesangial cells resulted in JNK activation and MCP-1 production, a phenotype seen in aging diabetic mesangial cells. Interestingly, MKP5 phosphatase activity was diminished by free radicals in vitro. Thus, OS may induce inflammation in mesangial cells by activating JNK through either a direct activation of JNK or indirectly by suppression of MKP5 activity. Proinflammatory phenotype of mesangial cells may contribute to chronic inflammatory lesions and disease progression of aging diabetic mice.

Mesangial cell-derived factors alter monocyte activation and function through inflammatory pathways: possible pathogenic role in diabetic nephropathy

2009 ◽  
Vol 297 (5) ◽  
pp. F1229-F1237 ◽  
Author(s):  
Danqing Min ◽  
J. Guy Lyons ◽  
James Bonner ◽  
Stephen M. Twigg ◽  
Dennis K. Yue ◽  
...  
Keyword(s):  
Diabetic Nephropathy ◽  
Conditioned Medium ◽  
High Glucose ◽  
Mesangial Cell ◽  
Mesangial Cells ◽  
Glomerular Mesangial Cells ◽  
Monocyte Chemoattractant Protein 1 ◽  
Tnf Α ◽  
Cell Conditioned Medium

Infiltration of macrophages to the kidney is a feature of early diabetic nephropathy. For this to happen monocytes must become activated, migrate from the circulation, and infiltrate the mesangium. This process involves degradation of extracellular matrix, a process mediated by matrix metalloproteinases (MMPs). In the present study we investigate the expression of proinflammatory cytokines TNF-α, IL-6, and MMP-9 in glomeruli of control and diabetic rodents and use an in vitro coculture system to examine whether factors secreted by mesangial cells in response to a diabetic milieu can induce monocyte MMP-9 expression and infiltration. After 8 wk of diabetes, the glomerular level of TNF-α, IL-6, and macrophage number and colocalization of MMP-9 with macrophage were increased ( P < 0.01). Coculture of THP1 monocytes and glomerular mesangial cells in 5 or 25 mM glucose increased MMP-9 (5 mM: 65% and 25 mM: 112%; P < 0.05) and conditioned media degradative activity (5 mM: 30.0% and 25 mM: 33.5%: P < 0.05). These effects were reproduced by addition of mesangial cell conditioned medium to THP1 cells. High glucose (25 mM) increased TNF-α, IL-6, and monocyte chemoattractant protein-1 in mesangial cell conditioned medium. These cytokines all increased adhesion and differentiation of THP1 cells ( P < 0.05), but only TNF-α and IL-6 increased MMP-9 expression (50- and 60-fold, respectively; P < 0.05). Our results show that mesangial cell-secreted factors increase monocyte adhesion, differentiation, MMP expression, and degradative capacity. High glucose could augment these effects by increasing mesangial cell proinflammatory cytokine secretion. This mesangial cell-monocyte interaction may be important in activating monocytes to migrate from the circulation to the kidney in the early stages of diabetic nephropathy.

scholarly journals Tribbles 3 Regulates the Fibrosis Cytokine TGF-β1 through ERK1/2-MAPK Signaling Pathway in Diabetic Nephropathy

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Luwei Zhang ◽  
Jinhang Zhang ◽  
Xinnong Liu ◽  
Shengli Liu ◽  
Jun Tian
Keyword(s):  
Diabetic Nephropathy ◽  
Signaling Pathway ◽  
High Glucose ◽  
Collagen Type ◽  
Mesangial Cells ◽  
Mapk Signaling ◽  
Mapk Signaling Pathway ◽  
Collagen Type Iv ◽  
Diabetic Mice ◽  
Type Iv

To reveal the expression and possible role of tribbles homolog 3 (TRB3) in the incidence of type 2 diabetic nephropathy, we used immunohistochemistry, real-time quantitative PCR, western blot analysis, and enzyme-linked immunosorbent assay (ELISA) to study the expression of TRB3, extracellular signal-regulated kinase 1/2 mitogen-activated protein kinase (ERK1/2 MAPK), transforming growth factorβ1 (TGF-β1), and collagen type IV in kidneys of db/db diabetic mice and in murine renal mesangial cells stimulated with high glucose. The expression of TRB3, TGF-β1, and collagen type IV was increased in kidneys of db/db diabetic mice. TGF-β1 and collagen type IV regulated by high glucose through ERK1/2 MAPK were downregulated by silencing TRB3 in renal mesangial cells. TRB3 may be involved in diabetic nephropathy by regulating the fibrosis cytokine TGF-β1 and collagen type IV through the ERK1/2 MAPK signaling pathway.

scholarly journals Circ-ACTR2 aggravates the high glucose-induced cell dysfunction of human renal mesangial cells through mediating the miR-205-5p/HMGA2 axis in diabetic nephropathy

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Jie Yun ◽  
Jinyu Ren ◽  
Yufei Liu ◽  
Lijuan Dai ◽  
Liqun Song ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Diabetic Nephropathy ◽  
High Glucose ◽  
Cell Injury ◽  
Mesangial Cells ◽  
Protein Detection ◽  
Cell Counting ◽  
Luciferase Reporter ◽  
Enzyme Linked Immunosorbent Assay ◽  
Cell Dysfunction

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.

scholarly journals High Glucose and Lipopolysaccharide Prime NLRP3 Inflammasome via ROS/TXNIP Pathway in Mesangial Cells

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Hong Feng ◽  
Junling Gu ◽  
Fang Gou ◽  
Wei Huang ◽  
Chenlin Gao ◽  
...  
Keyword(s):  
Diabetic Nephropathy ◽  
Nlrp3 Inflammasome ◽  
High Glucose ◽  
Mesangial Cells ◽  
Central Component ◽  
Dependent Manner ◽  
Glomerular Mesangial Cells ◽  
Interacting Protein

While inflammation is considered a central component in the development in diabetic nephropathy, the mechanism remains unclear. The NLRP3 inflammasome acts as both a sensor and a regulator of the inflammatory response. The NLRP3 inflammasome responds to exogenous and endogenous danger signals, resulting in cleavage of procaspase-1 and activation of cytokines IL-1β, IL-18, and IL-33, ultimately triggering an inflammatory cascade reaction. This study observed the expression of NLRP3 inflammasome signaling stimulated by high glucose, lipopolysaccharide, and reactive oxygen species (ROS) inhibitor N-acetyl-L-cysteine in glomerular mesangial cells, aiming to elucidate the mechanism by which the NLRP3 inflammasome signaling pathway may contribute to diabetic nephropathy. We found that the expression of thioredoxin-interacting protein (TXNIP), NLRP3, and IL-1βwas observed by immunohistochemistry in vivo. Simultaneously, the mRNA and protein levels of TXNIP, NLRP3, procaspase-1, and IL-1βwere significantly induced by high glucose concentration and lipopolysaccharide in a dose-dependent and time-dependent manner in vitro. This induction by both high glucose and lipopolysaccharide was significantly inhibited by N-acetyl-L-cysteine. Our results firstly reveal that high glucose and lipopolysaccharide activate ROS/TXNIP/ NLRP3/IL-1βinflammasome signaling in glomerular mesangial cells, suggesting a mechanism by which inflammation may contribute to the development of diabetic nephropathy.

P0983INHIBITION OF ATF3 BY RAF INHIBITOR GW5074 ON DIABETIC NEPHROPATHY

2020 ◽  
Vol 35 (Supplement_3) ◽  
Author(s):  
Jee Young Han ◽  
Jin Joo Cha ◽  
Young Sun Kang ◽  
Jung Yeon Ghee ◽  
Ji Ae Yoo ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Transcription Factor ◽  
Diabetic Nephropathy ◽  
High Glucose ◽  
Kinase Inhibitor ◽  
Protective Role ◽  
Activating Transcription Factor 3 ◽  
Diabetic Mice ◽  
Mice Model ◽  
Gene Expressions

Abstract Background and Aims Activating Transcription Factor 3 (ATF3) is a stress-adaptive transcription factor, which has been suggested to be involved in maintaining glucose homeostasis. ATF3 respond rapidly to various stimuli like high glucose, fatty acids and oxidative stress, and is observed to either protective or detrimental effects in diabetic condition. Therefore to elucidate the exact role in diabetic nephropathy of ATF3, we investigated the role of ATF3 by inhibition with Raf-inhibitor GW5047 on diabetic mice model. Method ATF3 level was examined in the mouse podocytes and NRK cells with either overexpression or downregulation with ATF3. 8 week db/m and db/db mice as the model of diabetic mice were examined for the expression of ATF3 and were treated with GW5074, a Raf1 kinase inhibitor targeting the ATF3 intraperitoneally with a dose of 0.5mg/kg for 12 weeks. Results In cultured mouse podocytes and NRK cells, high glucose and angiotensin II markedly increased ATF3 expression. Gene Expressions of NOX4, MCP-1 and NF-kB were augmented by ATF3, and were attenuated by ATF3 siRNA. In db/db mice, plasma ATF3 level was not different from control db/m, however the urinary ATF3 excretion was significantly higher. Treatment of GW5074 decreased urinary ATF3 excretion. After 12 week treatment, serum creatinine level was significantly lower in the treatment db/db group, with less systemic oxidative stress. There were no significant differences in body weight, whereas the food intake was decreased in GW5047 group. Overall lipid profile or HOMA-IR, HbA1c level was not different from each group. Serum adiponectin were otherwise increased in GW5074 group. Urinary excretion of albumin at 2 month of treatment decreased with urinary nephrin excretion. Trend of increased gene expression of JNK, p-38, smad2, ERK which was downregulated by GW5074 was noted. Conclusion These findings suggest that in diabetic condition, the activation of ATF3 is associated pathogenesis of diabetic nephropathy and targeting ATF3 may have a protective role in the disease progression.

scholarly journals Long Non-Coding RNA NEAT1 Regulates Pyroptosis in Diabetic Nephropathy via Mediating the miR-34c/NLRP3 Axis

2020 ◽  
Vol 45 (4) ◽  
pp. 589-602 ◽  
Author(s):  
Jin-Feng Zhan ◽  
Hong-Wei Huang ◽  
Chong Huang ◽  
Li-Li Hu ◽  
Wen-Wei Xu
Keyword(s):  
Diabetic Nephropathy ◽  
Target Gene ◽  
Molecular Mechanisms ◽  
Mesangial Cells ◽  
Receptor Protein ◽  
Luciferase Reporter ◽  
Glomerular Mesangial Cells ◽  
Non Coding Rna ◽  
Vitro Model

Introduction: Diabetic nephropathy (DN) is a serious complication of diabetes mellitus and is considered to be a sterile inflammatory disease. Increasing evidence suggest that pyroptosis and subsequent inflammatory response play a key role in the pathogenesis of DN. However, the underlying cellular and molecular mechanisms responsible for pyroptosis in DN are largely unknown. Methods: The rat models of DN were successfully established by single 65 mg/kg streptozotocin treatment. Glomerular mesangial cells were exposed to 30 mmol/L high glucose media for 48 h to mimic the DN environment in vitro. Gene and protein expressions were determined by quantitative real-time PCR and Western blot. Cell viability and pyroptosis were measured by MTT assay and flow cytometry analysis, respectively. The relationship between lncRNA NEAT1, miR-34c, and Nod-like receptor protein-3 (NLRP3) was confirmed by luciferase reporter assay. Results: We found that upregulation of NEAT1 was associated with the increase of pyroptosis in DN models. miR-34c, as a target gene of NEAT1, mediated the effect of NEAT1 on pyroptosis in DN by regulating the expression of NLRP3 as well as the expressions of caspase-1 and interleukin-1β. Either miR-34c inhibition or NLRP3 overexpression could reverse the accentuation of pyroptosis and inflammation by sh-NEAT1 transfection in the in vitro model of DN. Conclusions: Our findings suggested NEAT1 and its target gene miR-34c regulated cell pyroptosis via mediating NLRP3 in DN, providing new insights into understanding the molecular mechanisms of pyroptosis in the pathogenesis of DN.

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.

O-linked β-N-acetylglucosamine supports p38 MAPK activation by high glucose in glomerular mesangial cells

2011 ◽  
Vol 301 (4) ◽  
pp. E713-E726 ◽  
Author(s):  
Howard Goldberg ◽  
Catharine Whiteside ◽  
I. George Fantus
Keyword(s):  
Diabetic Nephropathy ◽  
P38 Mapk ◽  
High Glucose ◽  
Transforming Growth Factor ◽  
Kinase Inhibitor ◽  
Mesangial Cells ◽  
Mapk Signaling ◽  
Mitogen Activated Protein Kinase ◽  
Glomerular Mesangial Cells ◽  
Matrix Accumulation

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.

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