scholarly journals Distinct glucose-dependent stress responses revealed by translational profiling in pancreatic β-cells

2007 ◽  
Vol 192 (1) ◽  
pp. 179-187 ◽  
Author(s):  
Isabel C Greenman ◽  
Edith Gomez ◽  
Claire E J Moore ◽  
Terence P Herbert
Keyword(s):  
Stress Responses ◽  
High Glucose ◽  
Glucose Concentration ◽  
High Glucose Concentration ◽  
Cell Integrity ◽  
Β Cells ◽  
Pancreatic Β Cells ◽  
Interacting Protein ◽  
Thioredoxin Interacting Protein ◽  
Specific Subset

In pancreatic β-cells, following an acute (within 1 h) increase in glucose concentration, there are rapid changes in the expression of a large subset of proteins. The change in the expression of many of these proteins is mediated by a post-transcriptional mechanism through either increases or decreases in the rate of translation from pre-existing transcripts. These proteins, whose synthesis is rapidly up- or down-regulated in response to glucose, are likely important in mounting the correct response to changes in plasma glucose concentrations. However, the vast majority of these proteins remain unidentified. Therefore, in order to identify these proteins, we analysed changes in the levels of mRNAs associated with polysomes (i.e. actively translating mRNAs) isolated from mouse insulinoma 6 cells incubated at either 0.5 or 20 mM glucose for 1 h. Changes in the levels of polysomal mRNAs in response to glucose were analysed using affymetrix oligonucleotide microarrays (translational profiling). This work revealed that, in response to a change in glucose concentration, the abundance of 313 transcripts associated with polysomes changed by more than 1.5-fold, of which the abundance of 37 changed by more than twofold. The majority of these transcripts encoded proteins associated with metabolism or gene expression. More detailed analysis showed that a number of mRNAs encoding proteins associated with the induction of oxidative stress, including thioredoxin-2 and thioredoxin-interacting protein were rapidly redistributed onto heavier polysomes at high glucose concentration, indicating an increase in their expression. At low glucose concentration, when the general rate of protein synthesis is low, a number of mRNAs encoding integrated stress response proteins, including ATF4 and CHOP10, associate with heavier polysomes, indicating that their expression is up-regulated. In conclusion, translational profiling has revealed that, at either low or at high glucose concentration, β-cells rapidly increase the synthesis of a specific subset of proteins that are likely important in maintaining β-cell integrity and survival during conditions of nutritional stress.

scholarly journals Glucose-Dependent Changes in SNARE Protein Levels in Pancreatic β-Cells

Endocrinology ◽  
2011 ◽  
Vol 152 (4) ◽  
pp. 1290-1299 ◽  
Author(s):  
Benjamín Torrejón-Escribano ◽  
Jessica Escoriza ◽  
Eduard Montanya ◽  
Juan Blasi
Keyword(s):  
Insulin Secretion ◽  
Protein Expression ◽  
High Glucose ◽  
Glucose Concentration ◽  
Snare Proteins ◽  
High Glucose Concentration ◽  
Β Cells ◽  
Pancreatic Β Cells ◽  
In Vivo Models ◽  
Insulin Granule

Abstract Prolonged exposure to high glucose concentration alters the expression of a set of proteins in pancreatic β-cells and impairs their capacity to secrete insulin. The cellular and molecular mechanisms that lie behind this effect are poorly understood. In this study, three either in vitro or in vivo models (cultured rat pancreatic islets incubated in high glucose media, partially pancreatectomized rats, and islets transplanted to streptozotozin-induced diabetic mice) were used to evaluate the dependence of the biological model and the treatment, together with the cell location (insulin granule or plasma membrane) of the affected proteins and the possible effect of sustained insulin secretion, on the glucose-induced changes in protein expression. In all three models, islets exposed to high glucose concentrations showed a reduced expression of secretory granule-associated vesicle-soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins synaptobrevin/vesicle-associated membrane protein 2 and cellubrevin but minor or no significant changes in the expression of the membrane-associated target-SNARE proteins syntaxin1 and synaptosomal-associated protein-25 and a marked increase in the expression of synaptosomal-associated protein-23 protein. The inhibition of insulin secretion by the L-type voltage-dependent calcium channel nifedipine or the potassium channel activator diazoxide prevented the glucose-induced reduction in islet insulin content but not in vesicle-SNARE proteins, indicating that the granule depletion due to sustained exocytosis was not involved in the changes of protein expression induced by high glucose concentration. Altogether, the results suggest that high glucose has a direct toxic effect on the secretory pathway by decreasing the expression of insulin granule SNARE-associated proteins.

scholarly journals Protective Effect of Siegesbeckia orientalis on Pancreatic β-Cells under High Glucose-Induced Glucotoxicity

2021 ◽  
Vol 11 (22) ◽  
pp. 10963
Author(s):  
Chi-Chang Chang ◽  
Jer-Yiing Houng ◽  
Shih-Wei Wang ◽  
Chin-Feng Hsuan ◽  
Yung-Chuan Lu ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Antioxidant Enzymes ◽  
Insulin Secretion ◽  
Protective Effect ◽  
Normal Level ◽  
High Glucose ◽  
Glucose Concentration ◽  
Β Cells ◽  
Pancreatic Β Cells ◽  
Siegesbeckia Orientalis

The glucotoxicity caused by long-term exposure of β-cells to high glucose (HG) conditions may lead to the generation of more reactive oxygen species (ROS), reduce the activity of antioxidant enzymes, cause cell damage and apoptosis, and induce insulin secretion dysfunction. Siegesbeckia orientalis linne is a traditional folk herbal medicine used to treat snake bites, rheumatoid arthritis, allergies, and immune deficiencies. In this study, we evaluated the protective effect of S. orientalis ethanol extract (SOE) on cell death and oxidative stress in RIN-m5f pancreatic β-cells stimulated by two HG concentrations (50–100 mM). In the cell viability assay, SOE could significantly increase the survival rate of pancreatic β-cells under HG-induced conditions. For the oxidative stress induced by HG condition, the treatment of SOE effectively reduced the ROS formation, increased the content of intracellular glutathione, and up-regulated the expression of antioxidant enzymes, catalase, superoxide dismutase, and glutathione peroxidase. As a result, the SOE treatment could decrease the glucotoxicity-mediated oxidative damage on RIN-m5F β-cells. Moreover, SOE had the function of regulating insulin secretion in pancreatic β-cells under different HG-mediated conditions. It could decrease the increasing intracellular insulin secretion under the low glucose concentration to normal level; while increase the decreasing intracellular insulin secretion under the relatively high glucose concentration to normal level. Taken together, this study suggests that SOE has a protective effect on pancreatic β-cells under the HG-stimulated glucotoxic environment.

scholarly journals FMK, an Inhibitor of p90RSK, Inhibits High Glucose-Induced TXNIP Expression via Regulation of ChREBP in Pancreatic β Cells

2019 ◽  
Vol 20 (18) ◽  
pp. 4424
Author(s):  
Jung-Hwa Han ◽  
Suji Kim ◽  
Suji Kim ◽  
Heejung Lee ◽  
So-Young Park ◽  
...  
Keyword(s):  
High Glucose ◽  
Molecular Mechanisms ◽  
Cell Function ◽  
Nuclear Translocation ◽  
Ros Generation ◽  
Β Cells ◽  
Β Cell ◽  
Pancreatic Β Cells ◽  
Interacting Protein ◽  
Cell Dysfunction

Hyperglycemia is the major characteristic of diabetes mellitus, and a chronically high glucose (HG) level causes β-cell glucolipotoxicity, which is characterized by lipid accumulation, impaired β-cell function, and apoptosis. TXNIP (Thioredoxin-interacting protein) is a key mediator of diabetic β-cell apoptosis and dysfunction in diabetes, and thus, its regulation represents a therapeutic target. Recent studies have reported that p90RSK is implicated in the pathogenesis of diabetic cardiomyopathy and nephropathy. In this study, we used FMK (a p90RSK inhibitor) to determine whether inhibition of p90RSK protects β-cells from chronic HG-induced TXNIP expression and to investigate the molecular mechanisms underlying the effect of FMK on its expression. In INS-1 pancreatic β-cells, HG-induced β-cell dysfunction, apoptosis, and ROS generation were significantly diminished by FMK. In contrast BI-D1870 (another p90RSK inhibitor) did not attenuate HG-induced TXNIP promoter activity or TXNIP expression. In addition, HG-induced nuclear translocation of ChREBP and its transcriptional target molecules were found to be regulated by FMK. These results demonstrate that HG-induced pancreatic β-cell dysfunction resulting in HG conditions is associated with TXNIP expression, and that FMK is responsible for HG-stimulated TXNIP gene expression by inactivating the regulation of ChREBP in pancreatic β-cells. Taken together, these findings suggest FMK may protect against HG-induced β-cell dysfunction and TXNIP expression by ChREBP regulation in pancreatic β-cells, and that FMK is a potential therapeutic reagent for the drug development of diabetes and its complications.

scholarly journals GABA requires GLP-1R to exert its pancreatic function during STZ challenge

2020 ◽  
Vol 246 (3) ◽  
pp. 207-222 ◽  
Author(s):  
Weijuan Shao ◽  
Wenjuan Liu ◽  
Ping Liang ◽  
Zhuolun Song ◽  
Odisho Israel ◽  
...  
Keyword(s):  
Cell Mass ◽  
Gamma Aminobutyric Acid ◽  
Β Cells ◽  
Β Cell ◽  
Pancreatic Β Cells ◽  
Interacting Protein ◽  
Thioredoxin Interacting Protein ◽  
Beneficial Effects ◽  
Mouse Islets ◽  
Underlying Mechanisms

Gamma-aminobutyric acid (GABA) administration attenuates streptozotocin (STZ)-induced diabetes in rodent models with unclear underlying mechanisms. We found that GABA and Sitagliptin possess additive effect on pancreatic β-cells, which prompted us to ask the existence of common or unique targets of GLP-1 and GABA in pancreatic β-cells. Effect of GABA on expression of thioredoxin-interacting protein (TxNIP) was assessed in the INS-1 832/13 (INS-1) cell line, WT and GLP-1R–/– mouse islets. GABA was also orally administrated in STZ-challenged WT or GLP-1R–/– mice, followed by immunohistochemistry assessment of pancreatic islets. Effect of GABA on Wnt pathway effector β-catenin (β-cat) was examined in INS-1 cells, WT and GLP-1R–/– islets. We found that GABA shares a common feature with GLP-1 on inhibiting TxNIP, while this function was attenuated in GLP-1R–/– islets. In WT mice with STZ challenge, GABA alleviated several ‘diabetic syndromes’, associated with increased β-cell mass. These features were virtually absent in GLP-1R–/– mice. Knockdown TxNIP in INS-1 cells increased GLP-1R, Pdx1, Nkx6.1 and Mafa levels, associated with increased responses to GABA or GLP-1 on stimulating insulin secretion. Cleaved caspase-3 level can be induced by high-glucose, dexamethasone, or STZ in INS-1 cell, while GABA treatment blocked the induction. Finally, GABA treatment increased cellular cAMP level and β-cat S675 phosphorylation in WT but not GLP-1R–/– islets. We, hence, identified TxNIP as a common target of GABA and GLP-1 and suggest that, upon STZ or other stress challenge, the GLP-1R-cAMP-β-cat signaling cascade also mediates beneficial effects of GABA in pancreatic β-cell, involving TxNIP reduction.

High glucose concentration suppresses mesangial laminin B2 gene expression

1991 ◽  
Vol 5 (2-3) ◽  
pp. 118-120 ◽  
Author(s):  
Shigehiro Katayama ◽  
Mari Abe ◽  
Kiyoshi Tanaka ◽  
Akira Omoto ◽  
Kiyohiko Negishi ◽  
...  
Keyword(s):  
Gene Expression ◽  
High Glucose ◽  
Glucose Concentration ◽  
High Glucose Concentration
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