Unknown,Transcriptomics,Genomics,Proteomics

Dataset Information

Adipose Rab10 Knockout Causes Insulin Resistance through Impaired Glucose Uptake

ABSTRACT: Insulin action in adipocytes affects whole-body insulin sensitivity. Studies of adipose-specific Glut4 knockout mice have established that adipose Glut4 contributes to the control of systemic glucose homeostasis. Presumably, this reflects a role for Glut4-mediated glucose transport in the regulation of secreted adipokines. In cultured 3T3-L1 adipocytes, Rab10 GTPase is required for insulin-stimulated translocation of Glut4 (Sano et al., 2007). The physiological importance of adipose Rab10 and the significance of its role in the control of Glut4 vesicle trafficking in vivo are unknown. Here we report that adipocytes from adipose-specific Rab10 knockout mice have a ~50% reduction in glucose uptake and Glut4 translocation to the cell surface in response to insulin, demonstrating a role for Rab10 in Glut4 trafficking. Moreover, hyperinsulinemic-euglycemic clamp shows decreased whole-body glucose uptake as well as impaired suppression of hepatic glucose production in adipose Rab10 knockout mice. Thus, fully functional Glut4 vesicle trafficking in adipocytes is critical for maintaining insulin sensitivity. Comparative transcriptome analysis of perigonadal adipose tissue demonstrates significant transcriptional similarities between adipose Rab10 knockout mice and adipose Glut4 knockout mice, consistent with the notion that the phenotypic similarities between the two models are mediated by reduced insulin-stimulated glucose transport into adipocytes. Transcriptome sequencing of perigonadal white adipose tissue

ORGANISM(S): Mus musculus

SUBMITTER: Akanksha Verma

PROVIDER: E-GEOD-70123 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Publications

Disruption of Adipose Rab10-Dependent Insulin Signaling Causes Hepatic Insulin Resistance.

Vazirani Reema P RP Verma Akanksha A Sadacca L Amanda LA Buckman Melanie S MS Picatoste Belen B Beg Muheeb M Torsitano Christopher C Bruno Joanne H JH Patel Rajesh T RT Simonyte Kotryna K Camporez Joao P JP Moreira Gabriela G Falcone Domenick J DJ Accili Domenico D Elemento Olivier O Shulman Gerald I GI Kahn Barbara B BB McGraw Timothy E TE

Diabetes 20160325 6

Insulin controls glucose uptake into adipose and muscle cells by regulating the amount of GLUT4 in the plasma membrane. The effect of insulin is to promote the translocation of intracellular GLUT4 to the plasma membrane. The small Rab GTPase, Rab10, is required for insulin-stimulated GLUT4 translocation in cultured 3T3-L1 adipocytes. Here we demonstrate that both insulin-stimulated glucose uptake and GLUT4 translocation to the plasma membrane are reduced by about half in adipocytes from adipose- ...[more]

PMID: 27207531

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Project description:Aims/Hypothesis. The aim of this study was to determine the potential involvement of LMO3-dependent pathways in the modulation of key functions of mature adipocytes during obesity. Methods. Based on a recently engineered hybrid rAAV serotype Rec2 shown to efficiently transduce both brown adipose tissue (BAT) and white adipose tissue (WAT), we delivered YFP or Lmo3 to epididymal WAT (eWAT) of C57Bl6/J mice on a high fat diet (HFD). The effects of eWAT transduction on metabolic parameters were evaluated 10 weeks later. To further define the role of LMO3 in insulin-stimulated glucose uptake, insulin signaling, adipocyte bioenergetics as well as endocrine function, experiments were conducted in 3T3-L1 adipocytes and newly differentiated human primary mature adipocytes, engineered for transient gain- or loss of LMO3 expression, respectively. Results. AAV transduction of eWAT results in strong and stable Lmo3 expression specifically in the adipocyte fraction over a course of 10 weeks with HFD feeding. Lmo3 expression in eWAT significantly improved glucose clearance and insulin sensitivity in diet-induced obesity, paralleled by increased serum adiponectin. On a molecular level, LMO3 expression in eWAT increased pathways indicative of adipogenesis and PPARg signaling as well as mitochondrial activity, paralleled by a suppression of adipose tissue fibrosis. In vitro, Lmo3 expression in 3T3-L1 adipocytes increased insulin-stimulated GLUT4 translocation and glucose uptake as well as mitochondrial oxidative capacity in addition to fatty acid oxidation. LMO3 overexpression promoted, while silencing of LMO3 suppressed, mitochondrial oxidative capacity in human mature adipocytes. Conclusions. LMO3 expression in visceral adipose tissue regulates multiple genes that preserve adipose tissue functionality during obesity, such as glucose tolerance, insulin sensitivity and adiponectin secretion. Together with increased PPARγ activity, these gene expression changes promote insulin-induced GLUT4 translocation, glucose uptake in addition to increased mitochondrial oxidative capacity, limiting HFD-induced adipose dysfunction. These data add LMO3 as a novel regulator improving visceral adipose tissue function during obesity.

Project description:Type 2 diabetes (T2D) is major cause of mortality and morbidity. The key manifestations of this disease are insulin resistance (IR), hyperglycemia and hyperinsulinemia. Secretion of insulin from the endocrine pancreas is triggered by elevated circulating glucose and acts on skeletal muscle and adipose tissues to remove excess glucose from the blood (1). This is achieved through a series of intracellular events that trigger the translocation of vesicles containing the glucose transporter 4 (GLUT4) to the surface of skeletal muscle cells and adipocytes (2,3). This process is impaired in patients with IR or T2D and insulin fails to promote GLUT4 translocation, thus resulting in inefficient glucose uptake in storage tissue and hyperglycemia (4). Chronic hyperglycemic condition increases the risk of cardiovascular disease, stroke, neuropathy, and death (5). Previously developed insulin sensitizer like thiazolidinediones (TZDs) have proven effective in improving glycemic control, however, they significantly increase the risk of cardiovascular disease due to their agonist activity at PPAR(6-8). Consequently, identifying insulin sensitizers that restore insulin-stimulated GLUT4 translocation in diabetic patients without targeting PPAR is urgently needed. The discovery of such molecules has been challenging due to the lack of a GLUT4 translocation assay amenable to high throughput screening (HTS). For this reason, we have developed a new luminescence based HTS assay that allows real time monitoring of GLUT4 translocation in mammalian cells and further adapted the assay to measure GLUT4 translocation in live mice. Using this assay, we identified a new insulin sensitizer which greatly improves insulin-dependent glucose uptake in storage tissues and glucose tolerance in insulin resistant rodents. This new insulin sensitizers acts through interaction with the Unc119 family of proteins which are known to facilitate the transport of specific cargos (9) but had not yet been implicated in insulin action or GLUT4 translocation. This study identifies new PPAR-independent insulin sensitizers with in-vivo efficacy and identify Unc119 proteins as new targets for the treatment of T2D.

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Dataset Information

Adipose Rab10 Knockout Causes Insulin Resistance through Impaired Glucose Uptake

Publications

Disruption of Adipose Rab10-Dependent Insulin Signaling Causes Hepatic Insulin Resistance.

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