scholarly journals AKAP1 Deficiency Attenuates Diet‐Induced Obesity and Insulin Resistance by Promoting Fatty Acid Oxidation and Thermogenesis in Brown Adipocytes

2021 ◽  
pp. 2002794
Author(s):  
Lele Ji ◽  
Ya Zhao ◽  
Linjie He ◽  
Jing Zhao ◽  
Tian Gao ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Fatty Acid ◽  
Fatty Acid Oxidation ◽  
Acid Oxidation ◽  
Brown Adipocytes ◽  
Diet Induced Obesity

scholarly journals Suppression of Fatty Acid Oxidation by Thioesterase Superfamily Member 2 in Skeletal Muscle Promotes Hepatic Steatosis and Insulin Resistance

2021 ◽  
Author(s):  
Norihiro Imai ◽  
Hayley T. Nicholls ◽  
Michele Alves-Bezerra ◽  
Yingxia Li ◽  
Anna A. Ivanova ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Skeletal Muscle ◽  
Fatty Acids ◽  
Fatty Acid ◽  
Hepatic Steatosis ◽  
Fatty Acid Oxidation ◽  
Fatty Acyl ◽  
Pentose Phosphate ◽  
Acid Oxidation ◽  
Diet Induced Obesity

ABSTRACTThioesterase superfamily member 2 (Them2) is highly expressed in oxidative tissues where it hydrolyzes long chain fatty acyl-CoA esters to free fatty acids and CoA. Although mice globally lacking Them2 (Them2-/-) are protected against diet-induced obesity, insulin resistance and hepatic steatosis, liver-specific Them2-/- mice remain susceptible. To explore the contribution of Them2 in extrahepatic tissues, we created mice with Them2 deleted in skeletal muscle (S-Them2-/-), cardiac muscle (C-Them2-/-) or adipose tissue (A-Them2-/-). When fed a high-fat diet, S-Them2-/- but not C-Them2-/- or A-Them2-/- mice exhibited reduced weight gain. Only S-Them2-/- mice exhibited improved glucose homeostasis together with improved insulin sensitivity in skeletal muscle. Increased rates of fatty acid oxidation in skeletal muscle of S-Them2-/- mice were reflected in alterations in skeletal muscle metabolites, including short chain fatty acids, branched chain amino acids and the pentose phosphate pathway. Protection from diet-induced hepatic steatosis in S-Them2-/- mice was attributable to increased VLDL triglyceride secretion rates in support of demands of increased muscle fatty acid utilization. These results reveal a key role for skeletal muscle Them2 in the pathogenesis of diet-induced obesity, insulin resistance and hepatic steatosis.

scholarly journals A common East Asian-specific ALDH2 mutation causes obesity and insulin resistance: therapeutic effect of reducing toxic aldehydes by ALDH2 activation

2020 ◽  
Author(s):  
Yi-Cheng Chang ◽  
Hsiao-Lin Lee ◽  
Wenjin Yang ◽  
Meng-Lun Hsieh ◽  
Cai-Cin Liu ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Fatty Acid ◽  
Electron Transport ◽  
Energy Expenditure ◽  
Fatty Liver ◽  
Fatty Acid Oxidation ◽  
Water Soluble ◽  
Acid Oxidation ◽  
Diet Induced Obesity ◽  
Brown Adipose

Abstract Obesity and type 2 diabetes have reached pandemic proportion. In particular, the population with diabetes is expected to rise rapidly in East and South Asia. ALDH2 (acetaldehyde dehydrogenase 2, mitochondrial) is the key metabolizing enzyme of acetaldehyde and other toxic aldehydes, such as 4-hydroxynonenal (4-HNE). A missense mutation, Glu504Lys of ALDH2 (denoted as the ALDH2*2 allele) is prevalent in 560 million East Asians, resulting in reduced ALDH2 enzymatic activity. We found that Aldh2*2/*2 homozygous knock-in (KI) mice mimicking human Glu504Lys mutation were prone to develop diet-induced obesity, glucose intolerance, insulin resistance, and fatty liver on a high-fat high-sucrose diet compared with controls. The Aldh2 KI mice demonstrated reduced energy expenditure and thermogenesis. Proteomic analyses of the brown adipose tissue (BAT) of the Aldh2 KI mice identified increased 4-HNE-adducted proteins involved in fatty acid oxidation and electron transport chain. Fatty acid oxidation rate and mitochondrial electron transport activity were reduced in the BAT of the Aldh2 KI mice, which explained the decrease in thermogenesis and energy expenditure. AD-9308 is a water-soluble prodrug of a potent and highly selective ALDH2 activator AD-5591. In vitro, AD-5591 enhanced both WT and mutant ALDH2 enzymatic activities. AD-9308 allosterically activates ALDH2 mainly by partially blocking the substrate exit tunnel, thereby accelerating the substrate-enzyme collision. In vivo, AD-9308 treatment reduced serum 4-HNE levels, ameliorated diet-induced obesity and fatty liver, and improved glucose homeostasis in both Aldh2 WT and KI mice dose-dependently. Our data highlight the therapeutic potential of reducing toxic aldehyde levels by activating ALDH2 for treating metabolic diseases.

scholarly journals MicroRNA-27b-3p regulates function and metabolism in insulin resistance cells by inhibiting receptor tyrosine kinase-like orphan receptor 1

2018 ◽  
Vol 16 ◽  
pp. 205873921876205
Author(s):  
Yong Liu ◽  
Guohui Wang ◽  
Xiangwu Yang ◽  
Pengzhou Li ◽  
Hao Ling ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Fatty Acid ◽  
Tyrosine Kinase ◽  
Glucose Uptake ◽  
Fatty Acid Oxidation ◽  
Receptor Tyrosine Kinase ◽  
Cell Model ◽  
Orphan Receptor ◽  
Acid Oxidation ◽  
Metabolism Disorder

Type 2 diabetes mellitus (T2DM) is associated with insulin resistance-induced lipid and glucose metabolism disorder. The study was aimed to explore the potential functional role of microRNA (miR)-27b-3p in T2DM, as well as underlying mechanisms. An insulin resistance cell model was induced in HepG2 cells and then expression of miR-27b-3p and receptor tyrosine kinase-like orphan receptor 1 (ROR1) was analyzed. The expression of miR-27b-3p was overexpressed or silenced, and the relationship between ROR1 and miR-27b-3p was investigated. Thereafter, the effects of miR-27b-3p on percentage of glucose uptake, fatty acid oxidation and cell cycle were analyzed. The expressions of miR-27b-3p were significantly increased, while the ROR1 levels were statistically decreased in the cells of the model group. Overexpression of miR-27b-3p dramatically decreased the levels of ROR1 and the percentage of glucose uptake, but had no effects on fatty acid oxidation. ROR1 was a target of miR-27b-3p. Moreover, overexpression of miR-27b-3p could remarkably highlight the percentages of cells at G0/G1 phase, but decreased the percentages of cells at S phase. In conclusion, our results suggest that miR-27b-3p regulates the function and metabolism of insulin resistance cells by inhibiting ROR1. miR-27b-3p might be a potential drug target in treating T2DM.

scholarly journals Therapeutic Inhibition of miR-33 Promotes Fatty Acid Oxidation but Does Not Ameliorate Metabolic Dysfunction in Diet-Induced Obesity

2015 ◽  
Vol 35 (12) ◽  
pp. 2536-2543 ◽  
Author(s):  
Denuja Karunakaran ◽  
Laura Richards ◽  
Michele Geoffrion ◽  
Danyk Barrette ◽  
Ryan J. Gotfrit ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Oxidation ◽  
Acid Oxidation ◽  
Metabolic Dysfunction ◽  
Diet Induced Obesity

Abstract 437: Increasing Cardiac Fatty Acid Oxidation Protects Against High Fat Diet Induced Cardiomyopathy in Mice

2016 ◽  
Vol 119 (suppl_1) ◽  
Author(s):  
Dan Shao ◽  
Nathan Roe ◽  
Loreta D Tomasi ◽  
Alyssa N Braun ◽  
Ana Mattos ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Oxidation ◽  
Cardiac Dysfunction ◽  
High Fat Diet ◽  
Heart Weight ◽  
Acid Oxidation ◽  
Acid Uptake ◽  
High Fat ◽  
Diet Induced Obesity ◽  
Cardiac Lipotoxicity

In the obese and diabetic heart, an imbalance between fatty acid uptake and fatty acid oxidation (FAO) promotes the development of cardiac lipotoxicity. We previously showed that cardiac specific deletion of acetyl CoA carboxylase 2 (ACC2) was effective in increasing myocardial FAO while maintaining normal cardiac function and energetics. In this study, we tested the hypothesis that ACC2 deletion in an adult heart would prevent the cardiac lipotoxic phenotype in a mouse model of diet-induced obesity. ACC2 flox/flox (CON) and ACC2 flox/flox-MerCreMer+ (iKO) after tamoxifen injection were subjected to a high fat diet (HFD) for 24 weeks. HFD induced similar body weight gain and glucose intolerance in CON and iKO. In isolated Langendorff-perfused heart experiments, HFD feeding increased FAO 1.6-fold in CON mice which was increased to 2.5-fold in iKO mice compared with CON on chow diet. Fractional shortening was significantly decreased in CON-HFD (32.8±2.8% vs. 39.2±3.2%, p< 0.05, n=5-6), but preserved in iKO-HFD mice (42.8±2.3%, vs. 38.5±1.4%, n=6), compared to respective chow fed controls. Diastolic function, assessed by E’/A’ ratio using tissue Doppler imaging, was significantly decreased in CON-HFD mice (1.11±0.08 vs. 0.91±0.09, p<0.05 n=5-6), while no difference was observed in iKO-HFD compared to iKO-chow (1.10±0.03 vs. 1.09±0.04, n=6). Heart weight /Tibia length ratio was significantly higher in CON than iKO mice after HFD feeding (7.19±0.22 vs. 6.47±0.28, p<0.05, n=6). Furthermore, HFD induced mitochondria super complex II, III and V instability, which was attenuated in iKO-HFD mice. These data indicate that elevated myocardial FAO per se does not cause the development of cardiac dysfunction in obese animals. In fact, enhancing FAO via ACC2 deletion prevents HFD induced cardiac dysfunction and attenuates pathological hypertrophy. These effects may be mediated, in part, by maintenance of mitochondrial integrity. Taken together, our findings suggest that promoting cardiac FAO is an effective strategy to resist the development of cardiac lipotoxicity during diet-induced obesity.

RS4-type resistant starch prevents high-fat diet-induced obesity via increased hepatic fatty acid oxidation and decreased postprandial GIP in C57BL/6J mice

2010 ◽  
Vol 298 (3) ◽  
pp. E652-E662 ◽  
Author(s):  
Akira Shimotoyodome ◽  
Junko Suzuki ◽  
Daisuke Fukuoka ◽  
Ichiro Tokimitsu ◽  
Tadashi Hase
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Oxidation ◽  
Resistant Starch ◽  
High Fat Diet ◽  
Acid Oxidation ◽  
High Fat ◽  
Fat Utilization ◽  
Hepatic Fatty Acid ◽  
Diet Induced Obesity ◽  
Hepatic Fatty Acid Oxidation

Chemically modified starches (CMS) are RS4-type resistant starch, which shows a reduced availability, as well as high-amylose corn starch (HACS, RS2 type), compared with the corresponding unmodified starch. Previous studies have shown that RS4 increases fecal excretion of bile acids and reduces zinc and iron absorption in rats. The aim of this study was to investigate the effects of dietary RS4 supplementation on the development of diet-induced obesity in mice. Weight- and age-matched male C57BL/6J mice were fed for 24 wk on a high-fat diet containing unmodified starch, hydroxypropylated distarch phosphate (RS4), or HACS (RS2). Those fed the RS4 diet had significantly lower body weight and visceral fat weight than those fed either unmodified starch or the RS2 diet. Those fed the RS4 diet for 4 wk had a significantly higher hepatic fatty acid oxidation capacity and related gene expression and lower blood insulin than those fed either unmodified starch or the RS2 diet. Indirect calorimetry showed that the RS4 group exhibited higher energy expenditure and fat utilization compared with the RS2 group. When gavaged with fat (trioleate), RS4 stimulated a lower postprandial glucose-dependent insulinotropic polypeptide (GIP; incretin) response than RS2. Higher blood GIP levels induced by chronic GIP administration reduced fat utilization in high-fat diet-fed mice. In conclusion, dietary supplementation with RS4-type resistant starch attenuates high-fat diet-induced obesity more effectively than RS2 in C57BL/6J mice, which may be attributable to lower postprandial GIP and increased fat catabolism in the liver.

scholarly journals Inhibition of myostatin protects against diet-induced obesity by enhancing fatty acid oxidation and promoting a brown adipose phenotype in mice

Diabetologia ◽  
2011 ◽  
Vol 55 (1) ◽  
pp. 183-193 ◽  
Author(s):  
C. Zhang ◽  
C. McFarlane ◽  
S. Lokireddy ◽  
S. Masuda ◽  
X. Ge ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Oxidation ◽  
Acid Oxidation ◽  
Diet Induced Obesity ◽  
Brown Adipose

Mitochondrial function and dysfunction in exercise and insulin resistanceThis paper article is one of a selection of papers published in this Special Issue, entitled 14th International Biochemistry of Exercise Conference – Muscles as Molecular and Metabolic Machines, and has undergone the Journal’s usual peer review process.

2009 ◽  
Vol 34 (3) ◽  
pp. 440-446 ◽  
Author(s):  
Graham P. Holloway
Keyword(s):  
Insulin Resistance ◽  
Skeletal Muscle ◽  
Fatty Acid ◽  
Fatty Acid Oxidation ◽  
Peer Review Process ◽  
Acid Oxidation ◽  
Fatty Acid Transport ◽  
Acid Transport ◽  
Mitochondrial Content ◽  
Mitochondrial Fatty Acid

Fatty acid translocase (FAT/CD36) represents a novel flexible regulatory system, influencing rates of mitochondrial fatty acid metabolism in both human and rodent skeletal muscle. During exercise, the subcellular redistribution of FAT/CD36 provides a mechanism to increase not only plasma membrane fatty acid transport, but also mitochondrial fatty acid oxidation. This FAT/CD36-mediated coordination of long chain fatty acid (LCFA) transport and oxidation is an intriguing model in the context of insulin resistance. It was believed for almost a decade that reductions in fatty acid oxidation increased intramuscular lipids, thereby contributing to insulin resistance. A reduction in mitochondrial content may reduce the capacity of skeletal muscle LCFA oxidation; however, work from my laboratory has shown that, in some insulin-resistant muscles, mitochondrial content and fatty acid oxidation are both increased, yet these muscles accumulate lipids because of a considerably greater increase in fatty acid transport. Therefore, an alternative model is being considered, in which the balance between LCFA uptake and oxidation is a determining factor in the development of insulin resistance. A permanent redistribution of the LCFA transport protein FAT/CD36 to the sarcolemmal has been consistently found, which results in an increased rate of LCFA transport. This work suggests that the accumulation of skeletal muscle lipids, regardless of changes in mitochondria, is attributable to an increased rate of LCFA transport that exceeds the capacity for oxidation.

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