The chaperone proteins HSP70, HSP40/DnaJ and GRP78/BiP suppress misfolding and formation of β-sheet-containing aggregates by human amylin: a potential role for defective chaperone biology in Type 2 diabetes

2010 ◽  
Vol 432 (1) ◽  
pp. 113-121 ◽  
Author(s):  
Vita Chien ◽  
Jacqueline F. Aitken ◽  
Shaoping Zhang ◽  
Christina M. Buchanan ◽  
Anthony Hickey ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Potential Role ◽  
Β Cell ◽  
Molar Ratios ◽  
Irreversible Aggregation ◽  
Chaperone Binding ◽  
Human Amylin ◽  
Β Sheet ◽  
Glucose Regulated Protein

Misfolding of the islet β-cell peptide hA (human amylin) into β-sheet-containing oligomers is linked to β-cell apoptosis and the pathogenesis of T2DM (Type 2 diabetes mellitus). In the present study, we have investigated the possible effects on hA misfolding of the chaperones HSP (heat-shock protein) 70, GRP78/BiP (glucose-regulated protein of 78 kDa/immunoglobulin heavy-chain-binding protein) and HSP40/DnaJ. We demonstrate that hA underwent spontaneous time-dependent β-sheet formation and aggregation by thioflavin-T fluorescence in solution, whereas rA (rat amylin) did not. HSP70, GRP78/BiP and HSP40/DnaJ each independently suppressed hA misfolding. Maximal molar protein/hA ratios at which chaperone activity was detected were 1:200 (HSP70, HSP40/DnaJ and GRP78/BiP). By contrast, none of the chaperones modified the secondary structure of rA. hA, but not rA, was co-precipitated independently with HSP70 and GRP78/BiP by anti-amylin antibodies. As these effects occur at molar ratios consistent with chaperone binding to relatively rare misfolded hA species, we conclude that HSP70 and GRP78/BiP can detect and bind misfolded hA oligomers, thereby effectively protecting hA against bulk misfolding and irreversible aggregation. Defective β-cell chaperone biology could contribute to hA misfolding and initiation of apoptosis in T2DM.

INCRETIN AND DIABETES

2011 ◽  
pp. 5-10
Author(s):  
Huu Dang Tran
Keyword(s):  
Type 2 Diabetes ◽  
Cell Proliferation ◽  
Glycaemic Control ◽  
Animal Studies ◽  
Dipeptidyl Peptidase ◽  
Pancreatic Β Cell ◽  
Β Cell ◽  
Glucose Sensitivity ◽  
Cell Glucose

The incretins are peptide hormones secreted from the gut in response to food. They increase the secretion of insulin. The incretin response is reduced in patients with type 2 diabetes so drugs acting on incretins may improve glycaemic control. Incretins are metabolised by dipeptidyl peptidase, so selectively inhibiting this enzyme increases the concentration of circulating incretins. A similar effect results from giving an incretin analogue that cannot be cleaved by dipeptidyl peptidase. Studies have identified other actions including improvement in pancreatic β cell glucose sensitivity and, in animal studies, promotion of pancreatic β cell proliferation and reduction in β cell apoptosis.

Liraglutide Therapy in a Prediabetic State: Rethinking the Evidence

2020 ◽  
Vol 16 (7) ◽  
pp. 699-715 ◽  
Author(s):  
Georgios S. Papaetis
Keyword(s):  
Type 2 Diabetes ◽  
Glucose Tolerance ◽  
Cell Function ◽  
Normal Glucose Tolerance ◽  
Current Evidence ◽  
Β Cell ◽  
Prediabetic State ◽  
New Therapeutic Approaches ◽  
Normal Glucose

Background: Prediabetes is defined as a state of glucose metabolism between normal glucose tolerance and type 2 diabetes. Continuous β-cell failure and death are the reasons for the evolution from normal glucose tolerance to prediabetes and finally type 2 diabetes. Introduction: The necessity of new therapeutic approaches in order to prevent or delay the development of type 2 diabetes is obligatory. Liraglutide, a long-acting GLP-1 receptor agonist, has 97% homology for native GLP-1. Identification of the trophic and antiapoptotic properties of liraglutide in preclinical studies, together with evidence of sustained β-cell function longevity during its administration in type 2 diabetes individuals, indicated its earliest possible administration during this disease, or even before its development, so as to postpone or delay its onset. Methods: Pubmed and Google databases have been thoroughly searched and relevant studies were selected. Results: This paper explores the current evidence of liraglutide administration both in humans and animal models with prediabetes. Also, it investigates the safety profile of liraglutide treatment and its future role to postpone or delay the evolution of type 2 diabetes. Conclusion: Liralgutide remains a valuable tool in our therapeutic armamentarium for individuals who are overweight or obese and have prediabetes. Future well designed studies will give valuable information that will help clinicians to stratify individuals who will derive the most benefit from this agent, achieving targeted therapeutic strategies.

scholarly journals Visceral Adiposity Index is associated with Insulin Resistance, impaired Insulin Secretion, and β-cell dysfunction in subjects at risk for Type 2 Diabetes

2021 ◽  
pp. 100013
Author(s):  
Froylan David Martínez-Sánchez ◽  
Valerie Paola Vargas-Abonce ◽  
Andrea Rocha-Haro ◽  
Romina Flores-Cardenas ◽  
Milagros Fernández-Barrio ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Type 2 Diabetes ◽  
At Risk ◽  
Insulin Secretion ◽  
Visceral Adiposity ◽  
Visceral Adiposity Index ◽  
Β Cell ◽  
Cell Dysfunction ◽  
Impaired Insulin

scholarly journals Gut microbiota influence in type 2 diabetes mellitus (T2DM)

Gut Pathogens ◽  
2021 ◽  
Vol 13 (1) ◽  
Author(s):  
A. L. Cunningham ◽  
J. W. Stephens ◽  
D. A. Harris
Keyword(s):  
Diabetes Mellitus ◽  
Type 2 Diabetes ◽  
Type 2 Diabetes Mellitus ◽  
Gut Microbiota ◽  
Potential Role ◽  
Evidence Base ◽  
Human Metabolism ◽  
Altered Glucose

AbstractA strong and expanding evidence base supports the influence of gut microbiota in human metabolism. Altered glucose homeostasis is associated with altered gut microbiota, and is clearly associated with the development of type 2 diabetes mellitus (T2DM) and associated complications. Understanding the causal association between gut microbiota and metabolic risk has the potential role of identifying susceptible individuals to allow early targeted intervention.

scholarly journals Systemic Metabolic Alterations Correlate with Islet-Level Prostaglandin E2 Production and Signaling Mechanisms That Predict β-Cell Dysfunction in a Mouse Model of Type 2 Diabetes

Metabolites ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 58 ◽  
Author(s):  
Michael D. Schaid ◽  
Yanlong Zhu ◽  
Nicole E. Richardson ◽  
Chinmai Patibandla ◽  
Irene M. Ong ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Prostaglandin E2 ◽  
Genetic Model ◽  
Cell Mass ◽  
Arachidonic Acid Metabolite ◽  
Β Cell ◽  
Human Organ ◽  
Cell Dysfunction ◽  
Primary Mouse

The transition from β-cell compensation to β-cell failure is not well understood. Previous works by our group and others have demonstrated a role for Prostaglandin EP3 receptor (EP3), encoded by the Ptger3 gene, in the loss of functional β-cell mass in Type 2 diabetes (T2D). The primary endogenous EP3 ligand is the arachidonic acid metabolite prostaglandin E2 (PGE2). Expression of the pancreatic islet EP3 and PGE2 synthetic enzymes and/or PGE2 excretion itself have all been shown to be upregulated in primary mouse and human islets isolated from animals or human organ donors with established T2D compared to nondiabetic controls. In this study, we took advantage of a rare and fleeting phenotype in which a subset of Black and Tan BRachyury (BTBR) mice homozygous for the Leptinob/ob mutation—a strong genetic model of T2D—were entirely protected from fasting hyperglycemia even with equal obesity and insulin resistance as their hyperglycemic littermates. Utilizing this model, we found numerous alterations in full-body metabolic parameters in T2D-protected mice (e.g., gut microbiome composition, circulating pancreatic and incretin hormones, and markers of systemic inflammation) that correlate with improvements in EP3-mediated β-cell dysfunction.

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