scholarly journals Huntingtin-associated protein 1 plays an essential role in the pathogenesis of type 2 diabetes by regulating the translocation of GLUT4 in mouse adipocytes

2020 ◽  
Vol 8 (1) ◽  
pp. e001199
Author(s):  
Yan-Ju Gong ◽  
Ying Feng ◽  
Yuan-Yuan Cao ◽  
Jia Zhao ◽  
Wei Wu ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Body Weight ◽  
Adipose Tissue ◽  
Glucose Uptake ◽  
Hek293 Cells ◽  
Diabetic Mice ◽  
Glut4 Translocation ◽  
Mouse Adipocytes

ObjectiveGlucose disposal by insulin-responsive tissues maintains the body glucose homeostasis and insulin resistance leads to a risk of developing type 2 diabetes (T2DM). Insulin stimulates the translocation of glucose transporter isoform 4 (GLUT4) vesicles from intracellular compartments to the plasma membrane to facilitate glucose uptake. However, the underlying mechanisms of GLUT4 vesicle translocation are not well defined. Here we show the role of huntingtin-associated protein 1 (HAP1) in GLUT4 translocation in adipocytes and the pathogenesis of T2DM.Research design and methodsThe parameters for glucose metabolism including body weight, glucose tolerance and insulin tolerance were assessed in wild-type (WT) and Hap1+/- mice. HAP1 protein expression was verified in adipose tissue. Hap1 mRNA and protein expression was monitored in adipose tissue of high-fat diet (HFD)-induced diabetic mice. Insulin-stimulated GLUT4 vesicle translocation and glucose uptake were detected using immunofluorescence techniques and quantified in primary adipocytes from Hap1-/- mice. The interaction between HAP1 and GLUT4 was assessed by immunofluorescence colocalization and co-immunoprecipitation in HEK293 cells and adipose tissue. The role of sortilin in HAP1 and GLUT4 interaction was approved by co-immunoprecipitation and RNA interference.ResultsThe expression of Hap1 mRNA and protein was detected in WT mouse adipose tissue and downregulated in adipose tissue of HFD-induced diabetic mice. Hap1+/- mice exhibited increased body weight, pronounced glucose tolerance and significant insulin intolerance compared with the WT mice. HAP1 colocalized with GLUT4 in mouse adipocytes and cotransfected HEK293 cells. Furthermore, the insulin-stimulated GLUT4 vesicle translocation and glucose uptake were defective in Hap1-/- adipocytes. Finally, sortilin mediated the interaction of HAP1 and GLUT4.ConclusionsOur study showed that HAP1 formed a protein complex with GLUT4 and sortilin, and played a critical role in insulin-stimulated GLUT4 translocation in adipocytes. Its downregulation may contribute to the pathogenesis of diabetes.

scholarly journals Inflammation of adipose tissue. Part 2. Pathogenetic role in type 2 diabetes mellitus

2009 ◽  
Vol 55 (5) ◽  
pp. 43-48 ◽  
Author(s):  
V Shvarts
Keyword(s):  
Diabetes Mellitus ◽  
Type 2 Diabetes ◽  
Type 2 Diabetes Mellitus ◽  
Adipose Tissue ◽  
Cell Function ◽  
Signal Pathway ◽  
Insulin Signal ◽  
Kinase Cascade

This review deals with the role of adipose tissue inflammation (ATI) in the development of type 2 diabetes mellitus (DM2). ATI is regarded as a link between obesity and DM2. The review illustrates the involvement of main adipokines in pathogenesis of DM2 and provides a detailed description of such factors as impaired adiponectin and stimulation of cytokine production responsible for metabolic disorders, activation of lipolysis, in adipocytes, increased fatty acid and triglyceride levels, suppression of insulin activity at the receptor and intracellular levels. Adipokines, in the first place cytokines, act on the insulin signal pathway and affect the intracellular inflammatory kinase cascade. At the intercellular level, ATI stimulates JNK and IKK-beta/kB responsible for the development of insulin resistance via such mechanisms as activation of cytokine secretion in the adipose tissue, oxidative stress, and induction of endoplasmic reticulum enzymes. The key role of JNK and IKK-beta/kB in the inhibition of the insulin signal pathway is mediated through inactivation of insulin receptor substrate 1. Also, it is shown that ATI modulates B-cell function and promotes progressive reduction of insulin secretion.

scholarly journals Functional Interactomes of Genes Showing Association with Type-2 Diabetes and Its Intermediate Phenotypic Traits Point towards Adipo-Centric Mechanisms in Its Pathophysiology

Biomolecules ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 601
Author(s):  
Aditya Saxena ◽  
Nitin Wahi ◽  
Anshul Kumar ◽  
Sandeep Kumar Mathur
Keyword(s):  
Type 2 Diabetes ◽  
Adipose Tissue ◽  
Network Analysis ◽  
Potential Role ◽  
Phenotypic Traits ◽  
Protein Protein Interaction ◽  
Cellular Processes ◽  
Antidiabetic Treatment

The pathogenic mechanisms causing type 2 diabetes (T2D) are still poorly understood; a greater awareness of its causation can lead to the development of newer and better antidiabetic drugs. In this study, we used a network-based approach to assess the cellular processes associated with protein–protein interaction subnetworks of glycemic traits—HOMA-β and HOMA-IR. Their subnetworks were further analyzed in terms of their overlap with the differentially expressed genes (DEGs) in pancreatic, muscle, and adipose tissue in diabetics. We found several DEGs in these tissues showing an overlap with the HOMA-β subnetwork, suggesting a role of these tissues in β-cell failure. Many genes in the HOMA-IR subnetwork too showed an overlap with the HOMA-β subnetwork. For understanding the functional theme of these subnetworks, a pathway-to-pathway complementary network analysis was done, which identified various adipose biology-related pathways, containing genes involved in both insulin secretion and action. In conclusion, network analysis of genes showing an association between T2D and its intermediate phenotypic traits suggests their potential role in beta cell failure. These genes enriched the adipo-centric pathways and were expressed in both pancreatic and adipose tissue and, therefore, might be one of the potential targets for future antidiabetic treatment.

scholarly journals Adipose Tissue-Derived Signatures for Obesity and Type 2 Diabetes: Adipokines, Batokines and MicroRNAs

2019 ◽  
Vol 8 (6) ◽  
pp. 854 ◽  
Author(s):  
Min-Woo Lee ◽  
Mihye Lee ◽  
Kyoung-Jin Oh
Keyword(s):  
Type 2 Diabetes ◽  
Adipose Tissue ◽  
Energy Homeostasis ◽  
Metabolic Disturbances ◽  
Endocrine Organ ◽  
Brown Adipose ◽  
Exosomal Mirnas ◽  
Exosomal Mirna

Obesity is one of the main risk factors for type 2 diabetes mellitus (T2DM). It is closely related to metabolic disturbances in the adipose tissue that primarily functions as a fat reservoir. For this reason, adipose tissue is considered as the primary site for initiation and aggravation of obesity and T2DM. As a key endocrine organ, the adipose tissue communicates with other organs, such as the brain, liver, muscle, and pancreas, for the maintenance of energy homeostasis. Two different types of adipose tissues—the white adipose tissue (WAT) and brown adipose tissue (BAT)—secrete bioactive peptides and proteins, known as “adipokines” and “batokines,” respectively. Some of them have beneficial anti-inflammatory effects, while others have harmful inflammatory effects. Recently, “exosomal microRNAs (miRNAs)” were identified as novel adipokines, as adipose tissue-derived exosomal miRNAs can affect other organs. In the present review, we discuss the role of adipose-derived secretory factors—adipokines, batokines, and exosomal miRNA—in obesity and T2DM. It will provide new insights into the pathophysiological mechanisms involved in disturbances of adipose-derived factors and will support the development of adipose-derived factors as potential therapeutic targets for obesity and T2DM.

Reduction of Insulin Signaling Upregulates Angiopoietin-like Protein 4 Through Elevated Free Fatty Acids in Diabetic Mice

2011 ◽  
Vol 120 (03) ◽  
pp. 139-144 ◽  
Author(s):  
N. Mizutani ◽  
N. Ozaki ◽  
Y. Seino ◽  
A. Fukami ◽  
E. Sakamoto ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Fatty Acids ◽  
Adipose Tissue ◽  
Mrna Expression ◽  
High Fat Diet ◽  
Serum Triglyceride ◽  
Diabetic Mice ◽  
Brown Adipose

AbstractAngiopoietin-like protein 4 (Angptl4) is thought to cause an increase in serum triglyceride levels. In the present study, we elucidated Angptl4 expression in the mouse models of type 1 and type 2 diabetes mellitus, and investigated the possible mechanisms involved.Type 1 diabetes was induced in C57BL/6 J mice by treating them with streptozotocin (STZ). Type 2 diabetes was induced by feeding the mice a high-fat diet (HFD) for 18 weeks.The levels of Angptl4 mRNA expression in liver, white adipose tissue (WAT), and brown adipose tissue (BAT) were found to increase in the STZ diabetic mice relative to control mice. This effect was attenuated by insulin administration. In the HFD diabetic mice, the Angptl4 mRNA expression levels were increased in liver, WAT, and BAT. Treatment with metformin for 4 weeks attenuated the increased levels of Angptl4 mRNA. Fatty acids (FAs) such as palmitate and linoleate induced Angptl4 mRNA expression in H4IIE hepatoma cells and 3T3-L1 adipocytes. Treatment with insulin but not metformin attenuated FA-induced Angptl4 mRNA expression in H4IIE. Both insulin and metformin did not influence the effect of FAs in 3T3-L1 cells.These observations demonstrated that Angptl4 mRNA expression was increased through the elevated free FAs in diabetic mice.

Loss of HIF-1α impairs GLUT4 translocation and glucose uptake by the skeletal muscle cells

2014 ◽  
Vol 306 (9) ◽  
pp. E1065-E1076 ◽  
Author(s):  
Hidemitsu Sakagami ◽  
Yuichi Makino ◽  
Katsutoshi Mizumoto ◽  
Tsubasa Isoe ◽  
Yasutaka Takeda ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Skeletal Muscle ◽  
Protein Kinase ◽  
Glucose Metabolism ◽  
Glucose Uptake ◽  
Intracellular Signaling ◽  
Muscle Cells ◽  
Skeletal Muscle Cells ◽  
Glut4 Translocation

Defects in glucose uptake by the skeletal muscle cause diseases linked to metabolic disturbance such as type 2 diabetes. The molecular mechanism determining glucose disposal in the skeletal muscle in response to cellular stimuli including insulin, however, remains largely unknown. The hypoxia-inducible factor-1α (HIF-1α) is a transcription factor operating in the cellular adaptive response to hypoxic conditions. Recent studies have uncovered pleiotropic actions of HIF-1α in the homeostatic response to various cellular stimuli, including insulin under normoxic conditions. Thus we hypothesized HIF-1α is involved in the regulation of glucose metabolism stimulated by insulin in the skeletal muscle. To this end, we generated C2C12myocytes in which HIF-1α is knocked down by short-hairpin RNA and examined the intracellular signaling cascade and glucose uptake subsequent to insulin stimulation. Knockdown of HIF-1α expression in the skeletal muscle cells resulted in abrogation of insulin-stimulated glucose uptake associated with impaired mobilization of glucose transporter 4 (GLUT4) to the plasma membrane. Such defect seemed to be caused by reduced phosphorylation of the protein kinase B substrate of 160 kDa (AS160). AS160 phosphorylation and GLUT4 translocation by AMP-activated protein kinase activation were abrogated as well. In addition, expression of the constitutively active mutant of HIF-1α (CA-HIF-1α) or upregulation of endogenous HIF-1α in C2C12cells shows AS160 phosphorylation comparable to the insulin-stimulated level even in the absence of insulin. Accordingly GLUT4 translocation was increased in the cells expressing CA-HIF1α. Taken together, HIF-1α is a determinant for GLUT4-mediated glucose uptake in the skeletal muscle cells thus as a possible target to alleviate impaired glucose metabolism in, e.g., type 2 diabetes.

Transcriptome of the subcutaneous adipose tissue in response to oral supplementation of type 2 Leprdb obese diabetic mice with niacin-bound chromium

2006 ◽  
Vol 27 (3) ◽  
pp. 370-379 ◽  
Author(s):  
Cameron Rink ◽  
Sashwati Roy ◽  
Savita Khanna ◽  
Trenton Rink ◽  
Debasis Bagchi ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Blood Glucose ◽  
Specific Gene ◽  
Oral Glucose ◽  
Diabetic Mice ◽  
Fat Tissue ◽  
Obesity And Diabetes ◽  
Brown Adipose

The effects of oral niacin-bound chromium (NBC) supplementation on the subcutaneous fat tissue of type 2 Lepr db obese diabetic mice were examined using high-density comprehensive mouse genome (45,101 probe sets) expression arrays. The influence of such supplementation on the plasma cardiovascular risk factors of these mice was also investigated. Supplementation of NBC had no significant effect on age-dependent weight gain in the Lepr db obese diabetic mice. However, NBC lowered total cholesterol (TC), TC-to-HDL ratio, LDL cholesterol, and triglyceride levels while increasing HDL cholesterol in the blood plasma. No effect of NBC supplementation was observed on fasting blood glucose levels. Oral glucose tolerance test revealed a significantly improved clearance of blood glucose between 1 and 2 h of glucose challenge in NBC-supplemented mice. Unbiased genome-wide interrogation demonstrated that NBC resulted in the upregulation of muscle-specific gene expression in the fat tissue. Genes encoding proteins involved in glycolysis, muscle contraction, muscle metabolism, and muscle development were specifically upregulated in response to NBC supplementation. Genes in the adipose tissue that were downregulated in response to NBC supplementation included cell death-inducing DNA fragmentation factor (CIDEA) and uncoupling protein-1, which represent key components involved in the thermogenic role of brown adipose tissue and tocopherol transfer protein, the primary carrier of α-tocopherol to adipose tissue. The observation that CIDEA-null mice are resistant to obesity and diabetes suggests that the inhibitory role of NBC on CIDEA expression was favorable. Further studies testing the molecular basis of NBC function and long-term outcomes are warranted.

Estimation of ellagic acid and/or repaglinide effects on insulin signaling, oxidative stress, and inflammatory mediators of liver, pancreas, adipose tissue, and brain in insulin resistant/type 2 diabetic rats

2017 ◽  
Vol 42 (2) ◽  
pp. 181-192 ◽  
Author(s):  
Mohamed M. Amin ◽  
Mahmoud S. Arbid
Keyword(s):  
Type 2 Diabetes ◽  
Body Weight ◽  
Adipose Tissue ◽  
Insulin Signaling ◽  
Inflammatory Mediators ◽  
Ellagic Acid ◽  
Molecular Mechanisms ◽  
Combined Treatment ◽  
Albino Rats

Even though ellagic acid has previously been valued in many models of cancer, so far its full mechanistic effect as a natural antiapoptotic agent in the prevention of type 2 diabetes complications has not been completely elucidated, which was the goal of this study. We fed albino rats a high-fat fructose diet (HFFD) for 2 months to induce insulin resistance/type 2 diabetes and then treated the rats with ellagic acid (10 mg/kg body weight, orally) and/or repaglinide (0.5 mg/kg body weight, orally) for 2 weeks. At the serum level, ellagic acid challenged the consequences of HFFD, significantly improving the glucose/insulin balance, liver enzymes, lipid profile, inflammatory cytokines, redox level, adipokines, ammonia, and manganese. At the tissue level (liver, pancreas, adipose tissue, and brain), ellagic acid significantly enhanced insulin signaling, autophosphorylation, adiponectin receptors, glucose transporters, inflammatory mediators, and apoptotic markers. Remarkably, combined treatment with both ellagic acid and repaglinide had a more pronounced effect than treatment with either alone. These outcomes give new insight into the promising molecular mechanisms by which ellagic acid modulates numerous factors induced in the progression of diabetes.

scholarly journals The role of nonesterified fatty acids in pathogenesis of cardiovascular diseases

2010 ◽  
Vol 16 (1) ◽  
pp. 93-103 ◽  
Author(s):  
M. V. Tsvetkova ◽  
V. N. Khirmanov ◽  
N. N. Zybina
Keyword(s):  
Diabetes Mellitus ◽  
Type 2 Diabetes ◽  
Fatty Acids ◽  
Type 2 Diabetes Mellitus ◽  
Adipose Tissue ◽  
Risk Factor ◽  
Cardiovascular Diseases ◽  
Sudden Death

The paper reviews publications concerned the role of nonesterifi ed fatty acids (NEFA) in pathogenesis of cardiovascular diseases. NEFAs are four and more carbons chain length carbonic acids and they are presented in free form (nonesterifi ed) in human body. Plasma NEFAs are produced by the adipose tissue triglyceride lipolysis, another source are lipoproteins such as chylomicrons, very low density lipoproteins and intermediate density lipoproteins. Elevated NEFA concentrations in plasma are the risk factor of cardiovascular diseases and type 2 diabetes mellitus and the independent risk factor of hypertension and sudden death. NEFA plasma concentration is elevated in atherosclerosis, acute myocardial infarction, diabetes mellitus, obesity, hypertension, and often in metabolic syndrome. A probable cause of NEFAs accumulation in plasma may be overeating and low physical activity, which result in increase of adipose tissue mass, lipolysis intensifi cation and elevation of NEFAs concentration in plasma. The role of elevated plasma NEFA concentration in a number of conditions (abdominal obesity, atherogenic dyslipidemia, insulin resistance, type 2 diabetes mellitus, endothelial dysfunction, vascular infl ammation, atherosclerosis, hypertension, ischemic heart disease, rhythm disturbances, sudden death) and possible ways of their correction are discussed.

scholarly journals Important role of fat tissue hormones in development of comorbid chronic pancreatitis and obesity

2017 ◽  
Vol 37 (3) ◽  
pp. 30-35
Author(s):  
T. N. Hristich
Keyword(s):  
Diabetes Mellitus ◽  
Type 2 Diabetes ◽  
Type 2 Diabetes Mellitus ◽  
Adipose Tissue ◽  
Chronic Pancreatitis ◽  
Pancreatic Disease ◽  
Pancreatic Tissue ◽  
Visceral Adipose

Aim of this paper is to consider the role of hormones of the adipose tissue in mechanisms of obesity, metabolic syndrome, type 2 diabetes mellitus upon chronic pancreatitis. Materials and methods. The literature review indicates the value of visceral fat in the development of insulin resistance, dyslipidemia, including atherogenic one, taking into account the possible infiltration of pancreatic tissue by adipocytes. Participation of some adipocytokines of adipose tissue in the development of obesity upon chronic pancreatitis is highlighted. It is shown that in some cases the hormones of visceral adipose tissue, penetrating through the portal vein to the liver and then to the pancreas, aggravated the course of systemic chronic inflammation of the inherent chronic pancreatitis, promote steatosis and development of fatty pancreatic disease. Conclusion. Literary sources indicate the leading role of visceral adipose tissue and its hormones in the formation of obesity in chronic pancreatitis. Due to the infiltration of the pancreatic tissue by adipocytes, lipoidosis and steatosis develop. With the progression of the process type 2 diabetes mellitus, fatty liver or pancreatic disease, or cancer of these orhans. Consequently, there is a need for serious differentiated preventive and curative measures aimed at promoting a healthy lifestyle to improve the quality of life of patients suffering from chronic pancreatitis.

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