Molecular mechanisms involved in high glucose‐induced valve calcification in a 3D valve model with human valvular cells

High glucose and high fat are important inducements for the development and progression of diabetic cardiopathy. Salvianolic acid B (SAB), which is the most abundant and bioactive compound in Danshen, attenuates oxidative stress-related disorders, such as cardiovascular diseases, cerebral ischemia, and diabetes. However, the effect of SAB on diabetic cardiopathy is not clear. The aim of study was to investigate the effect and the underlying molecular mechanisms of SAB on diabetic cardiopathy in vitro model. The human umbilical vein endothelial (HUVEC) cells were treated with high glucose (HG, 30 mM) or high fat (palmitic acid, PA, 0.75 mM) in the presence or absence of SAB (100, 200, and 400 mg/L) and incubated for 24 h. We found that HG or PA induced apoptosis of HUVEC cells, while treatment with SAB inhibited the apoptosis. We also found that SAB reversed HG- or PA-induced oxidative stress, apoptosis cell cytokines production, and expression of thioredoxin-interacting protein (TXNIP). Moreover, SAB increased HG- or PA-induced expression of Sirtuin 1 (Sirt1), a nicotinamide adenine dinucleotide- (NAD+-) dependent histone deacetylase. Exposure of HUVEC cells to Ex527 (Sirt1 inhibitor) suppressed the effect of SAB on acetyl-p53 and procaspase-3 expressions. In conclusion, the results suggested that SAB could attenuate HUVEC cells damage treated with HG or PA via Sirt1 and might be a potential therapy agent for the diabetic cardiopathy treatment.

Download Full-text

Metformin Protects H9C2 Cardiomyocytes from High-Glucose and Hypoxia/Reoxygenation Injury via Inhibition of Reactive Oxygen Species Generation and Inflammatory Responses: Role of AMPK and JNK

Journal of Diabetes Research ◽

10.1155/2016/2961954 ◽

2016 ◽

Vol 2016 ◽

pp. 1-9 ◽

Cited By ~ 24

Author(s):

Mingyan Hu ◽

Ping Ye ◽

Hua Liao ◽

Manhua Chen ◽

Feiyan Yang

Keyword(s):

Reactive Oxygen Species ◽

Cell Viability ◽

High Glucose ◽

Molecular Mechanisms ◽

Ischemia Reperfusion ◽

Reactive Oxygen Species Generation ◽

Reactive Oxygen ◽

Oxygen Species ◽

Compound C ◽

Hypoxia Reoxygenation

Metformin is a first-line drug for the management of type 2 diabetes. Recent studies suggested cardioprotective effects of metformin against ischemia/reperfusion injury. However, it remains elusive whether metformin provides direct protection against hypoxia/reoxygenation (H/R) injury in cardiomyocytes under normal or hyperglycemic conditions. This study in H9C2 rat cardiomyoblasts was designed to determine cell viability under H/R and high-glucose (HG, 33 mM) conditions and the effects of cotreatment with various concentrations of metformin (0, 1, 5, and 10 mM). We further elucidated molecular mechanisms underlying metformin-induced cytoprotection, especially the possible involvement of AMP-activated protein kinase (AMPK) and Jun NH(2)-terminal kinase (JNK). Results indicated that 5 mM metformin improved cell viability, mitochondrial integrity, and respiratory chain activity under HG and/or H/R (P<0.05). The beneficial effects were associated with reduced levels of reactive oxygen species generation and proinflammatory cytokines (TNF-α, IL-1α, and IL-6) (P<0.05). Metformin enhanced phosphorylation level of AMPK and suppressed HG + H/R induced JNK activation. Inhibitor of AMPK (compound C) or activator of JNK (anisomycin) abolished the cytoprotective effects of metformin. In conclusion, our study demonstrated for the first time that metformin possessed direct cytoprotective effects against HG and H/R injury in cardiac cells via signaling mechanisms involving activation of AMPK and concomitant inhibition of JNK.

Download Full-text

TRAF3IP2 mediates high glucose-induced endothelin-1 production as well as endothelin-1-induced inflammation in endothelial cells

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00478.2017 ◽

2018 ◽

Vol 314 (1) ◽

pp. H52-H64 ◽

Cited By ~ 15

Author(s):

Jaume Padilla ◽

Andrea J. Carpenter ◽

Nitin A. Das ◽

Hemanth Kumar Kandikattu ◽

Susana López-Ongil ◽

...

Keyword(s):

Endothelial Cells ◽

Endothelial Cell ◽

High Glucose ◽

Therapeutic Target ◽

Molecular Mechanisms ◽

Vascular Complications ◽

Vascular Effects ◽

Interacting Protein ◽

Endothelin 1 ◽

Adapter Molecule

Hyperglycemia-induced production of endothelin (ET)-1 is a hallmark of endothelial dysfunction in diabetes. Although the detrimental vascular effects of increased ET-1 are well known, the molecular mechanisms regulating endothelial synthesis of ET-1 in the setting of diabetes remain largely unidentified. Here, we show that adapter molecule TRAF3 interacting protein 2 (TRAF3IP2) mediates high glucose-induced ET-1 production in endothelial cells and ET-1-mediated endothelial cell inflammation. Specifically, we found that high glucose upregulated TRAF3IP2 in human aortic endothelial cells, which subsequently led to activation of JNK and IKKβ. shRNA-mediated silencing of TRAF3IP2, JNK1, or IKKβ abrogated high-glucose-induced ET-converting enzyme 1 expression and ET-1 production. Likewise, overexpression of TRAF3IP2, in the absence of high glucose, led to activation of JNK and IKKβ as well as increased ET-1 production. Furthermore, ET-1 transcriptionally upregulated TRAF3IP2, and this upregulation was prevented by pharmacological inhibition of ET-1 receptor B using BQ-788, or inhibition of NADPH oxidase-derived reactive oxygen species using gp91ds-tat and GKT137831. Notably, we found that knockdown of TRAF3IP2 abolished ET-1-induced proinflammatory and adhesion molecule (IL-1β, TNF-α, monocyte chemoattractant protein 1, ICAM-1, VCAM-1, and E-selectin) expression and monocyte adhesion to endothelial cells. Finally, we report that TRAF3IP2 is upregulated and colocalized with CD31, an endothelial marker, in the aorta of diabetic mice. Collectively, findings from the present study identify endothelial TRAF3IP2 as a potential new therapeutic target to suppress ET-1 production and associated vascular complications in diabetes. NEW & NOTEWORTHY This study provides the first evidence that the adapter molecule TRAF3 interacting protein 2 mediates high glucose-induced production of endothelin-1 by endothelial cells as well as endothelin-1-mediated endothelial cell inflammation. The findings presented herein suggest that TRAF3 interacting protein 2 may be an important therapeutic target in diabetic vasculopathy characterized by excess endothelin-1 production.

Download Full-text

High glucose-induced phospholipase D activity in retinal pigment epithelium cells: New insights into the molecular mechanisms of diabetic retinopathy

Experimental Eye Research ◽

10.1016/j.exer.2019.04.028 ◽

2019 ◽

Vol 184 ◽

pp. 243-257 ◽

Cited By ~ 8

Author(s):

Paula E. Tenconi ◽

Vicente Bermúdez ◽

Gerardo M. Oresti ◽

Norma M. Giusto ◽

Gabriela A. Salvador ◽

...

Keyword(s):

Diabetic Retinopathy ◽

Retinal Pigment Epithelium ◽

Phospholipase D ◽

High Glucose ◽

Molecular Mechanisms ◽

Pigment Epithelium ◽

Retinal Pigment ◽

Retinal Pigment Epithelium Cells ◽

Epithelium Cells

Download Full-text

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

Journal of Ophthalmology ◽

10.1155/2016/6392658 ◽

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.

Download Full-text

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

Endocrine Connections ◽

10.1530/ec-16-0115 ◽

2017 ◽

Vol 6 (3) ◽

pp. 121-128 ◽

Cited By ~ 3

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.

Download Full-text

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

International Journal of Nephrology ◽

10.1155/2016/3846573 ◽

2016 ◽

Vol 2016 ◽

pp. 1-13 ◽

Cited By ~ 4

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.

Download Full-text

Psoralen alleviates high glucose-induced HK-2 cell injury by a mechanism involving miR-847 upregulation

10.21203/rs.3.rs-19865/v2 ◽

2020 ◽

Author(s):

Yongtao Lin ◽

Lili Zhong ◽

Hailun Li ◽

Yong Xu ◽

Xiang Li ◽

...

Keyword(s):

Western Blot ◽

High Glucose ◽

Molecular Mechanisms ◽

Cell Injury ◽

Human Kidney ◽

Cell Viability Assay ◽

Viability Assay ◽

Patients With Diabetes ◽

Apoptosis Assay ◽

Underlying Mechanisms

Abstract Background Diabetic nephropathy (DN) causes the vast proportion of excess mortality for patients with diabetes. Novel therapeutic approaches slowing down its incidence is still lacking. Psoralen is the major active ingredient of Psoralea corylifolia Linn. (PCL), which was used to treat a number of diseases. In this study, we aimed to investigate whether psoralen could alleviate DN and to explore the underlying mechanisms. Methods Cell viability assay and immunofluorescence were used to evaluate the effect of psoralen on high glucose (HG)-stimulated human kidney HK-2 cells. RT-qPCR was used to detect the expressions of miRNA in cells. Cell transfection, apoptosis assay and Western blot were further performed to explore the underlying molecular mechanisms. Results Psoralen alleviated HG-induced viability decrease of HK-2 cells via inhibiting apoptosis. Meanwhile, the secretion of inflammatory cytokines and extracellular matrix (ECM) accumulation induced by HG in HK-2 cells were also decreased by psoralen. In addition, the expression of miR-874 in HK-2 cells was significantly upregulated by psoralen. Western blot assays indicated that psoralen inhibiting TGF-β1/Smad2 signaling via upregulation of miR-874. Conclusion This study demonstrated that psoralen could significantly alleviate HG-induced HK-2 cell injury via upregulation of miR-874. Therefore, psoralen might serve as an agent for the treatment of DN.

Download Full-text

Sirt1 Mediated High-Glucose-Induced Aβ Deposition and Cognitive Impairment through Activation of the TLR9/p53 Pathway

10.21203/rs.3.rs-34315/v1 ◽

2020 ◽

Author(s):

Yue Sun ◽

Shiyu Zhu ◽

Jinliang Chen ◽

Yuxing Zhao ◽

Jing Zhou ◽

...

Keyword(s):

Cognitive Impairment ◽

High Glucose ◽

Molecular Mechanisms ◽

Short Term Memory ◽

Learning Ability ◽

Central Nervous System Complication ◽

Inflammatory Pathway ◽

Cognitive Improvement ◽

Lentiviral Infection

Abstract Background: Diabetic encephalopathy (DE) is a chronic central nervous system complication caused by diabetes mellitus (DM). β-amyloid (Aβ) deposition has been considered as the main cause of cognitive impairment in DE. Previous researches concerned the effect of canonical TLR9/Myd88 inflammatory pathway. However our study explored the function of non-inflammatory pathway of Toll-like receptor 9 (TLR9), acting on Sirt1 to influence Aβ deposition and cognitive function in DE.Results: We found that, compared with DM mice, TLR9-/-DM mice performed better learning ability and short-term memory, along with lower Aβ in hippocampi, but could be reversed by Sirt1 inhabition. Furthermore, in vitro, after intervention with high glucose and p53 over-expressed lentiviral infection, we observed the positive results of TLR9 inhibition, such as Sirt1 up-regulation, Aβ reduction or cognitive improvement, were altered (all P<0.05).Conclusions: we considered that TLR9/p53/Sirt1 signalling pathway induced by high glucose are one of molecular mechanisms underlying DE. These results not only confirm the importance of blood glucose management but also provide new insights for the diagnosis and treatment of DE.

Download Full-text

Divergent Actions of Pyruvate and ATP in Glucose-mediated Irinotecan Chemoresistance in Colorectal Cancer

10.21203/rs.3.rs-1175570/v1 ◽

2021 ◽

Author(s):

Chung-Yen Huang ◽

Yu-Chen Pai ◽

Linda Chia-Hui Yu

Keyword(s):

Colorectal Cancer ◽

Cell Lines ◽

High Glucose ◽

Structural Damage ◽

Topoisomerase I ◽

Molecular Mechanisms ◽

Flow Cytometric Analysis ◽

Quiescent State ◽

Altered Glucose ◽

Induced Apoptosis

Abstract Background: Altered glucose metabolism is associated with chemoresistance in colorectal cancer (CRC). The aim of this study was to illustrate the molecular mechanisms of glucose-mediated chemoresistance against irinotecan, a topoisomerase I inhibitor, focusing on the distinct roles of metabolites such as pyruvate and ATP in modulating cell death and proliferation. Methods: Four human CRC cell lines, tumorspheres, and mouse xenograft models were treated with various doses of irinotecan in the presence of high concentrations of glucose, pyruvate or ATP-encapsulated liposomes. Cell apoptosis was measured by DNA fragmentation and caspase activities, and necroptosis was evaluated by immunoprecipitation of receptor-interacting protein kinase (RIP) 1/3 complex. Cell cycles were assessed by flow cytometric analysis.Results: Human CRC cell lines treated with irinotecan in the presence of high glucose displayed increased cell viability and larger xenograft tumor sizes in mouse models compared to those treated in the presence of normal glucose. Irinotecan induced apoptosis and necroptosis, both of which were mitigated by high glucose. Liposomal ATP prevented irinotecan-induced apoptosis, while it had no effect on necroptosis. In contrast, pyruvate attenuated the RIP1/3-dependent necroptosis via free radical scavenging, without modulating apoptotic levels. Regarding the cell cycle, liposomal ATP aggravated irinotecan-induced G0/G1 shift whereas pyruvate diminished the G0/G1 shift, showing opposite effects on proliferation. Last, tumorsphere structural damage, an index of solid tumor responsiveness to chemotherapy, was determined. Liposomal ATP increased tumorsphere sizes while pyruvate prevented the deformation of spheroid mass. Conclusions: Glucose metabolites confer tumor chemoresistance via multiple modes of action. Glycolytic pyruvate attenuated irinotecan-induced necroptosis and potentiated drug insensitivity by shifting cells from a proliferative to quiescent state. On the other hand, ATP decreased irinotecan-induced apoptosis and promoted active cell proliferation, which might contribute to tumor recurrence.

Download Full-text