Resistance to high-fat diet-induced obesity and altered expression of adipose-specific genes in HSL-deficient mice

Harada, Kenji; Shen, Wen‐Jun; Patel, Shushma; Natu, Vanita; Wang, Jining; Osuga, Jun-ichi; Ishibashi, Shun; Kraemer, Fredric B.

doi:10.1152/ajpendo.00259.2003

Cited by 149 publications

(174 citation statements)

References 41 publications

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“…In addition, HSL-deficient mice had decreases in mRNA expressions of adipose LPL and PPARg. 43 However, the present study failed to find increases in HSL mRNA levels, possibly because of the lack of influence of both MUFA and P/S ratio on adipose HSL expression. Contrary to HSL mRNA levels, the fourfold difference in LPL mRNA levels seems to have led to the greatest difference in epididymal adipose tissue between the HMHR and OO groups.…”

Section: Discussioncontrasting

confidence: 85%

Differential effects of high MUFA with high or low P/S ratio (polyunsaturated to saturated fatty acids) on improving hepatic lipolytic enzymes and mediating PPARγ related with lipoprotein lipase and hormone-sensitive lipase of white adipose tissue in diet-induced obese hamster

Liou

et al. 2010

Int J Obes

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Objective: The aim of this study was to assess the relationship between high monounsaturated fatty acids (MUFAs) with different levels of polyunsaturated-to-saturated fatty acid (P/S) ratios and body fat loss in diet-induced obesity (DIO) models. Design: Male Golden Syrian hamsters were randomly assigned to the control group (n ¼ 12) and obesity group (n ¼ 24) for 4 weeks of the high-fat DIO period; afterward, six hamsters from each group were killed. The remaining control hamsters were still fed a low-fat diet. For an additional 8 weeks, the remaining obesity hamsters were switched to a low-fat diet and subdivided into three subgroups (n ¼ 6/group): the obesity-control (ObC) group, high MUFA with high P/S ratio oil (HMHR) group and olive oil (OO) group. Serum insulin and leptin concentrations were measured, and hepatic fatty acid metabolic enzymes and adipose differentiation markers were determined using enzyme activities analysis, western blot and semiquantification reverse-transcription PCR. Results: No difference was observed in the mean energy intake through all study periods. After the DIO period, the obesity group increased in weight gain and epididymal fat weight compared with the control group. DIO hamsters in the HMLR group had significant reductions in white adipose tissue deposition and plasma leptin levels, suppression in adipose peroxisome proliferator-activated receptor-g (PPARg) and lipoprotein lipase (LPL) mRNA expressions and increases in hepatic acyl-CoA oxidase and carnitine palmitoyltransferase-I activities and mRNA levels compared with those in the ObC group. The HMHR group had upregulated phosphorylation of hormone-sensitive lipase (HSL) relative to total HSL protein levels compared with the OO group. However, the OO group had significantly elevated hepatic de novo lipogenesis compared with the HMHR group. Conclusions: HMHR seemed to be beneficial in depleting white adipose tissue accumulation by decreasing adipose PPARg and LPL mRNA expressions and mediating phosphorylation of HSL, and by improving hepatic lipolytic enzyme activities and mRNA expressions involved in b-oxidation in DIO hamsters.

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Section: Discussioncontrasting

confidence: 85%

Differential effects of high MUFA with high or low P/S ratio (polyunsaturated to saturated fatty acids) on improving hepatic lipolytic enzymes and mediating PPARγ related with lipoprotein lipase and hormone-sensitive lipase of white adipose tissue in diet-induced obese hamster

Liou

et al. 2010

Int J Obes

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“…More than a decade ago, several groups demonstrated that mice systemically lacking HSL (HKO) also exhibit reduced lipogenesis and TG synthesis (6,9) and are resistant to HFD-induced obesity (8,9,36,37). This defect in lipoanabolic processes in HKO mice was associated with a marked down-regulation of PPARγ-dependent gene expression, leading to an almost complete loss of WAT in older HKO mice (6).…”

Section: Discussionmentioning

confidence: 99%

“…However, accumulating evidence suggested that a link exists between anabolic and catabolic lipid pathways (6)(7)(8)(9)(10). For example, the transcription of genes involved in both processes is activated by the adipogenic nuclear receptor PPAR-γ (4, 11).…”

mentioning

confidence: 99%

Hypophagia and metabolic adaptations in mice with defective ATGL-mediated lipolysis cause resistance to HFD-induced obesity

Schreiber

Hofer

Taschler

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

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Adipose triglyceride lipase (ATGL) initiates intracellular triglyceride (TG) catabolism. In humans, ATGL deficiency causes neutral lipid storage disease with myopathy (NLSDM) characterized by a systemic TG accumulation. Mice with a genetic deletion of ATGL (AKO) also accumulate TG in many tissues. However, neither NLSDM patients nor AKO mice are exceedingly obese. This phenotype is unexpected considering the importance of the enzyme for TG catabolism in white adipose tissue (WAT). In this study, we identified the counteracting mechanisms that prevent excessive obesity in the absence of ATGL. We used "healthy" AKO mice expressing ATGL exclusively in cardiomyocytes (AKO/cTg) to circumvent the cardiomyopathy and premature lethality observed in AKO mice. AKO/cTg mice were protected from high-fat diet (HFD)-induced obesity despite complete ATGL deficiency in WAT and normal adipocyte differentiation. AKO/cTg mice were highly insulin sensitive under hyperinsulinemic-euglycemic clamp conditions, eliminating insulin insensitivity as a possible protective mechanism. Instead, reduced food intake and altered signaling by peroxisome proliferator-activated receptor-gamma (PPAR-γ) and sterol regulatory element binding protein-1c in WAT accounted for the phenotype. These adaptations led to reduced lipid synthesis and storage in WAT of HFD-fed AKO/cTg mice. Treatment with the PPAR-γ agonist rosiglitazone reversed the phenotype. These results argue for the existence of an adaptive interdependence between lipolysis and lipid synthesis. Pharmacological inhibition of ATGL may prove useful to prevent HFDinduced obesity and insulin resistance.E ssentially all organisms face the problem of continuous energy demand in an environment of irregular food supply. To overcome this dilemma, metazoan organisms developed special storage depots for substrates that are used for energy production. In vertebrates, by far the most efficient energy reservoir is adipose tissue (1). This highly expandable organ is able to store all major nutritional components (fat, carbohydrates, and proteins) as triglycerides (TGs). Adipose tissue mass and TG content depend on the balance of anabolic and catabolic pathways. Lipid storage in response to nutrient supply involves the generation of adipocytes (adipogenesis), the induction of fatty acid (FA) synthesis from glucose and amino acids (de novo lipogenesis), and the synthesis of TGs (lipid synthesis). These processes are activated by a complex transcriptional network involving CCAAT/ enhancer-binding proteins (C/EBPs), sterol regulatory enhancer binding proteins (SREBPs), and the heterodimer of peroxisome proliferator-activated receptor-gamma (PPAR-γ) and retinoid-X receptor (RXR) (2, 3).The opposing metabolic pathway of TG catabolism (lipolysis) requires activation of enzymes called lipases. Adipose TG lipase (ATGL), hormone-sensitive lipase (HSL), and monoglyceride lipase (MGL) hydrolyze all three ester bonds of TGs in a stepwise manner to yield FAs and glycerol (4). Lipolysis is an exquisitely regulated proce...

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“…Until recently, HSL was believed to be the major regulatory enzyme in TAG hydrolysis. Studies in HSL-null mice, however, demonstrated normal WAT mass [68] and retained approximately 40% of TAG lipase activity [69][70][71]. While, HSL deficiency caused an accumulation of DAG in adipose tissue, no significant increase in TAG levels in WAT was observed [69].…”

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confidence: 98%

Triacylglycerol Metabolism In Adipose Tissue

et al. 2007

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Triacylglycerol (TAG) in adipose tissue serves as the major energy storage form in higher eukaryotes. Obesity, resulting from excess white adipose tissue, has increased dramatically in recent years resulting in a serious public health problem. Understanding of adipocyte-specific TAG synthesis and hydrolysis is critical to the development of strategies to treat and prevent obesity and its closely associated diseases, for example, Type 2 diabetes, hypertension and atherosclerosis. In this review, we present an overview of the major enzymes in TAG synthesis and lipolysis, including the recent discovery of a novel adipocyte TAG hydrolase. Keywords1-acylglycerol-3-phosphate acyltransferase; desnutrin/adipose triglyceride lipase; diacylglycerol acyltransferase; glycerol-3-phosphate acyltransferase; hormone-sensitive lipase; lipolysis; phosphatidic acid phosphatase; triacylglycerol White adipose tissue (WAT) is the major energy reserve in higher eukaryotes. The primary purposes of WAT are synthesis and storage of triacylglycerol (TAG) in periods of energy excess, and hydrolysis of TAG to generate fatty acids for use by other organs during periods of energy deprivation [1]. Adipose tissue also secretes adipokines that regulate energy intake and metabolism.The prevalence of obesity resulting from excess WAT has increased dramatically in recent years resulting in a serious public health problem, since obesity is closely associated with a number of disorders including Type 2 diabetes, hypertension and atherosclerosis [2]. While † Author for correspondence, University of California, Department of Nutritional Sciences & Toxicology, Berkeley, CA 94720, USA, adipocyte number has been shown to increase (hyperplasia) in morbid obesity, obesity is primarily attributed to adipocyte hypertrophy that occurs when TAG synthesis (esterification) exceeds TAG breakdown (lipolysis), resulting in elevated TAG storage [1]. Although it has been postulated that large adipocyte size may contribute to insulin resistance, the molecular mechanism is not clear.Paradoxically, the metabolic abnormalities typically found in obesity are also associated with lipodystrophies that are characterized by selective loss of adipose tissue from particular regions of the body [3][4][5][6]. Although the underlying molecular mechanisms are not clear, metabolic complications may result from ectopic storage of TAG in tissues such as the liver and muscle [7][8][9]. A proper capacity for TAG storage in adipocytes is clearly important for normal metabolic regulation. In view of the wide range of health problems associated with improper fat storage and release, it is critical to understand adipocyte-specific regulation of TAG synthesis and hydrolysis. Biosynthesis of triacylglycerolThe synthesis of phosphatidic acid and its subsequent conversion to TAG was described more than 40 years ago by Kennedy and coworkers [10], and is summarized in Figure 1. The initial committal step in this pathway is the formation of lysophosphatidic acid (1-acylglycerol-3-phosphate)...

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Resistance to high-fat diet-induced obesity and altered expression of adipose-specific genes in HSL-deficient mice

Cited by 149 publications

References 41 publications

Differential effects of high MUFA with high or low P/S ratio (polyunsaturated to saturated fatty acids) on improving hepatic lipolytic enzymes and mediating PPARγ related with lipoprotein lipase and hormone-sensitive lipase of white adipose tissue in diet-induced obese hamster

Differential effects of high MUFA with high or low P/S ratio (polyunsaturated to saturated fatty acids) on improving hepatic lipolytic enzymes and mediating PPARγ related with lipoprotein lipase and hormone-sensitive lipase of white adipose tissue in diet-induced obese hamster

Hypophagia and metabolic adaptations in mice with defective ATGL-mediated lipolysis cause resistance to HFD-induced obesity

Triacylglycerol Metabolism In Adipose Tissue

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