Inositol polyphosphate multikinase in adipocytes is dispensable for regulating energy metabolism and whole body metabolic homeostasis

2020 ◽  
Vol 319 (2) ◽  
pp. E401-E409
Author(s):  
Seulgi Lee ◽  
Jiyoon Beon ◽  
Min-Gyu Kim ◽  
Seyun Kim
Keyword(s):  
Adipose Tissue ◽  
Insulin Sensitivity ◽  
Glucose Homeostasis ◽  
Critical Role ◽  
Whole Body ◽  
Chow Diet ◽  
Inositol Polyphosphate ◽  
Fat Accumulation ◽  
Polyphosphate Metabolism ◽  
Inositol Polyphosphate Multikinase

Adipose tissue plays a central role in regulating whole body energy and glucose homeostasis at both organ and systemic levels. Inositol polyphosphates, such as 5-diphosphoinositol pentakisphosphate, reportedly control adipocyte functions and energy expenditure. However, the physiological roles of the inositol polyphosphate (IP) pathway in the adipose tissue are not yet fully defined. The aim of the present study was to test the hypothesis that inositol polyphosphate multikinase (IPMK), a key enzyme in the IP metabolism, plays a critical role in adipose tissue biology and obesity. We generated adipocyte-specific IPMK knockout ( Ipmk AKO) mice and evaluated metabolic phenotypes by measuring fat accumulation, glucose homeostasis, and insulin sensitivity in adult mice fed either a regular-chow diet or high-fat diet (HFD). Despite substantial reduction of IPMK, Ipmk AKO mice exhibited normal glucose tolerance and insulin sensitivity and did not show changes in fat accumulation in response to HFD-feeding. In addition, loss of IPMK had no major impact on thermogenic processes in response to cold exposure. Collectively, these findings suggest that adipocyte IPMK is dispensable for normal adipose tissue and its physiological functions in whole body metabolism, suggesting the complex roles that inositol polyphosphate metabolism has in the regulation of adipose tissue.

scholarly journals Brown Adipose Tissue Improves Whole-Body Glucose Homeostasis and Insulin Sensitivity in Humans

Diabetes ◽  
2014 ◽  
Vol 63 (12) ◽  
pp. 4089-4099 ◽  
Author(s):  
M. Chondronikola ◽  
E. Volpi ◽  
E. Borsheim ◽  
C. Porter ◽  
P. Annamalai ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Insulin Sensitivity ◽  
Brown Adipose Tissue ◽  
Glucose Homeostasis ◽  
Whole Body ◽  
Brown Adipose

Impact of human visceral and glutealfemoral adipose tissue transplant on glycemic control in a mouse model of diet-induced obesity

2020 ◽  
Vol 319 (3) ◽  
pp. E519-E528
Author(s):  
Thomas Tsiloulis ◽  
Arthe Raajendiran ◽  
Stacey N. Keenan ◽  
Geraldine Ooi ◽  
Renea A. Taylor ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Insulin Sensitivity ◽  
Glycemic Control ◽  
Glucose Homeostasis ◽  
High Fat Diet ◽  
Fasting Blood Glucose ◽  
Whole Body ◽  
High Fat ◽  
Positive Effects ◽  
Tissue Transplant

Regional distribution of adipose tissue is an important factor in conferring cardiometabolic risk and obesity-related morbidity. We tested the hypothesis that human visceral adipose tissue (VAT) impairs glucose homeostasis, whereas subcutaneous glutealfemoral adipose tissue (GFAT) protects against the development of impaired glucose homeostasis in mice. VAT and GFAT were collected from patients undergoing bariatric surgery and grafted onto the epididymal adipose tissue of weight- and age-matched severe, combined immunodeficient mice. SHAM mice underwent surgery without transplant of tissue. Mice were fed a high-fat diet after xenograft. Energy homeostasis, glucose metabolism, and insulin sensitivity were assessed 6 wk later. Xenograft of human adipose tissues was successful, as determined by histology, immunohistochemical evaluation of collagen deposition and angiogenesis, and maintenance of lipolytic function. Adipose tissue transplant did not affect energy expenditure, food intake, whole body substrate partitioning, or plasma free fatty acid, triglyceride, and insulin levels. Fasting blood glucose was significantly reduced in GFAT and VAT compared with SHAM, whereas glucose tolerance was improved only in mice transplanted with VAT compared with SHAM mice. This improvement was not associated with differences in whole body insulin sensitivity or plasma insulin between groups. Together, these data suggest that VAT improves glycemic control and GFAT does not protect against the development of high-fat diet-induced glucose intolerance. Hence, the intrinsic properties of VAT and GFAT do not necessarily explain the postulated negative and positive effects of these adipose tissue depots on metabolic health.

scholarly journals Galectin-3 gene deletion results in defective adipose tissue maturation and impaired insulin sensitivity and glucose homeostasis

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Claudia Blasetti Fantauzzi ◽  
Carla Iacobini ◽  
Stefano Menini ◽  
Martina Vitale ◽  
Gian Pio Sorice ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Insulin Sensitivity ◽  
Glucose Homeostasis ◽  
Cell Function ◽  
Whole Body ◽  
Metabolic Derangement ◽  
Abnormal Glucose Regulation ◽  
Galectin 3 ◽  
Β Cell Function

AbstractAdiposopathy is a pathological adipose tissue (AT) response to overfeeding characterized by reduced AT expandability due to impaired adipogenesis, which favors inflammation, insulin resistance (IR), and abnormal glucose regulation. However, it is unclear whether defective adipogenesis causes metabolic derangement also independently of an increased demand for fat storage. As galectin-3 has been implicated in both adipocyte differentiation and glucose homeostasis, we tested this hypothesis in galectin-3 knockout (Lgal3−/−) mice fed a standard chow. In vitro, Lgal3−/− adipocyte precursors showed impaired terminal differentiation (maturation). Two-month-old Lgal3−/− mice showed impaired AT maturation, with reduced adipocyte size and expression of adipogenic genes, but unchanged fat mass and no sign of adipocyte degeneration/death or ectopic fat accumulation. AT immaturity was associated with AT and whole-body inflammation and IR, glucose intolerance, and hyperglycemia. Five-month-old Lgal3−/− mice exhibited a more mature AT phenotype, with no difference in insulin sensitivity and expression of inflammatory cytokines versus WT animals, though abnormal glucose homeostasis persisted and was associated with reduced β-cell function. These data show that adipogenesis capacity per se affects AT function, insulin sensitivity, and glucose homeostasis independently of increased fat intake, accumulation and redistribution, thus uncovering a direct link between defective adipogenesis, IR and susceptibility to diabetes.

scholarly journals Adipocyte JAK2 Mediates Growth Hormone-Induced Hepatic Insulin Resistance

2016 ◽  
Author(s):  
Kevin C. Corbit ◽  
João Paulo G. Camporez ◽  
Jennifer L. Tran ◽  
Camella G. Wilson ◽  
Dylan Lowe ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Growth Hormone ◽  
Adipose Tissue ◽  
Insulin Sensitivity ◽  
Glucose Homeostasis ◽  
Metabolic Stress ◽  
Hepatic Insulin Resistance ◽  
Whole Body ◽  
Insulin Signal Transduction ◽  
Conditional Deletion

ABSTRACTFor nearly 100 years, Growth Hormone (GH) has been known to impact insulin sensitivity and risk of diabetes. However, the tissue governing the effects of GH signaling on insulin and glucose homeostasis remains unknown. Excess GH reduces fat mass and insulin sensitivity. Conversely, GH insensitivity (GHI) is associated with increased adiposity, augmented insulin sensitivity, and protection from diabetes. Here we induce adipocyte-specific GHI through conditional deletion of Jak2 (JAK2A), an obligate transducer of GH signaling. Similar to whole-body GHI, JAK2A mice had increased adiposity and extreme insulin sensitivity. Loss of adipocyte Jak2 augmented hepatic insulin sensitivity and conferred resistance to diet-induced metabolic stress without overt changes in circulating fatty acids. While GH injections induced hepatic insulin resistance in control mice, the diabetogenic action was absent in JAK2A mice. Adipocyte GH signaling directly impinged on both adipose and hepatic insulin signal transduction. Collectively, our results show that adipose tissue governs the effects of GH on insulin and glucose homeostasis. Further, we show that JAK2 mediates liver insulin sensitivity via an extra-hepatic, adipose tissue-dependent mechanism.

Abdominal obesity in BTBR male mice is associated with peripheral but not hepatic insulin resistance

2007 ◽  
Vol 292 (3) ◽  
pp. E936-E945 ◽  
Author(s):  
Jessica B. Flowers ◽  
Angie T. Oler ◽  
Samuel T. Nadler ◽  
YounJeong Choi ◽  
Kathryn L. Schueler ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Adipose Tissue ◽  
Insulin Sensitivity ◽  
Genetic Difference ◽  
Inbred Mouse ◽  
Hepatic Insulin Resistance ◽  
Whole Body ◽  
Glucose Disposal ◽  
Mouse Strains ◽  
Chow Diet

Insulin resistance is a common feature of obesity. BTBR mice have more fat mass than most other inbred mouse strains. On a chow diet, BTBR mice have elevated insulin levels relative to the C57BL/6J (B6) strain. Male F1 progeny of a B6 × BTBR cross are insulin resistant. Previously, we reported insulin resistance in isolated muscle and in isolated adipocytes in this strain. Whereas the muscle insulin resistance was observed only in male F1 mice, adipocyte insulin resistance was also present in male BTBR mice. We examined in vivo mechanisms of insulin resistance with the hyperinsulinemic euglycemic clamp technique. At 10 wk of age, BTBR and F1 mice had a >30% reduction in whole body glucose disposal primarily due to insulin resistance in heart, soleus muscle, and adipose tissue. The increased adipose tissue mass and decreased muscle mass in BTBR and F1 mice were negatively and positively correlated with whole body glucose disposal, respectively. Genes involved in focal adhesion, actin cytoskeleton, and inflammation were more highly expressed in BTBR and F1 than in B6 adipose tissue. The BTBR and F1 mice have higher levels of testosterone, which may be related to the pathological changes in adipose tissue that lead to systemic insulin resistance. Despite profound peripheral insulin resistance, BTBR and F1 mice retained hepatic insulin sensitivity. These studies reveal a genetic difference in body composition that correlates with large differences in peripheral insulin sensitivity.

scholarly journals Partial Deficiency of Zfp217 Resists High-Fat Diet-Induced Obesity by Increasing Energy Metabolism in Mice

2021 ◽  
Vol 22 (10) ◽  
pp. 5390
Author(s):  
Qianhui Zeng ◽  
Nannan Wang ◽  
Yaru Zhang ◽  
Yuxuan Yang ◽  
Shuangshuang Li ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Weight Gain ◽  
Insulin Sensitivity ◽  
Energy Metabolism ◽  
Glucose Tolerance ◽  
High Fat Diet ◽  
Chow Diet ◽  
High Fat ◽  
Glycolipid Metabolism ◽  
Partial Deficiency

Obesity-induced adipose tissue dysfunction and disorders of glycolipid metabolism have become a worldwide research priority. Zfp217 plays a crucial role in adipogenesis of 3T3-L1 preadipocytes, but about its functions in animal models are not yet clear. To explore the role of Zfp217 in high-fat diet (HFD)-induced obese mice, global Zfp217 heterozygous knockout (Zfp217+/−) mice were constructed. Zfp217+/− mice and Zfp217+/+ mice fed a normal chow diet (NC) did not differ significantly in weight gain, percent body fat mass, glucose tolerance, or insulin sensitivity. When challenged with HFD, Zfp217+/− mice had less weight gain than Zfp217+/+ mice. Histological observations revealed that Zfp217+/− mice fed a high-fat diet had much smaller white adipocytes in inguinal white adipose tissue (iWAT). Zfp217+/− mice had improved metabolic profiles, including improved glucose tolerance, enhanced insulin sensitivity, and increased energy expenditure compared to the Zfp217+/+ mice under HFD. We found that adipogenesis-related genes were increased and metabolic thermogenesis-related genes were decreased in the iWAT of HFD-fed Zfp217+/+ mice compared to Zfp217+/− mice. In addition, adipogenesis was markedly reduced in mouse embryonic fibroblasts (MEFs) from Zfp217-deleted mice. Together, these data indicate that Zfp217 is a regulator of energy metabolism and it is likely to provide novel insight into treatment for obesity.

scholarly journals FABP4-Cre Mediated Expression of Constitutively Active ChREBP Protects Against Obesity, Fatty Liver, and Insulin Resistance

Endocrinology ◽  
2015 ◽  
Vol 156 (11) ◽  
pp. 4020-4032 ◽  
Author(s):  
Alli M. Nuotio-Antar ◽  
Naravat Poungvarin ◽  
Ming Li ◽  
Michael Schupp ◽  
Mahmoud Mohammad ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Adipose Tissue ◽  
Fatty Liver ◽  
Binding Protein ◽  
Western Diet ◽  
Whole Body ◽  
Lipid Homeostasis ◽  
Chow Diet ◽  
Fatty Acid Binding ◽  
Constitutively Active

Carbohydrate response element binding protein (ChREBP) regulates cellular glucose and lipid homeostasis. Although ChREBP is highly expressed in many key metabolic tissues, the role of ChREBP in most of those tissues and the consequent effects on whole-body glucose and lipid metabolism are not well understood. Therefore, we generated a transgenic mouse that overexpresses a constitutively active ChREBP isoform under the control of the fatty acid binding protein 4-Cre-driven promoter (FaChOX). Weight gain was blunted in male, but not female, FaChOX mice when placed on either a normal chow diet or an obesogenic Western diet. Respiratory exchange ratios were increased in Western diet-fed FaChOX mice, indicating a shift in whole-body substrate use favoring carbohydrate metabolism. Western diet-fed FaChOX mice showed improved insulin sensitivity and glucose tolerance in comparison with controls. Hepatic triglyceride content was reduced in Western diet-fed FaChOX mice in comparison with controls, suggesting protection from fatty liver. Epididymal adipose tissue exhibited differential expression of genes involved in differentiation, browning, metabolism, lipid homeostasis, and inflammation between Western diet-fed FaChOX mice and controls. Our findings support a role for ChREBP in modulating adipocyte differentiation and adipose tissue metabolism and inflammation as well as consequent risks for obesity and insulin resistance.

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