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Calorie restriction results in leanness, which is linked to metabolic conditions that favor longevity. We show here that deficiency of the triglyceride synthesis enzyme acyl CoA:diacylglycerol acyltransferase 1 (DGAT1), which promotes leanness, also extends longevity without limiting food intake. Female DGAT1-deficient mice were protected from age-related increases in body fat, tissue triglycerides, and inflammation in white adipose tissue. This protection was accompanied by increased mean and maximal life spans of ~25% and ~10%, respectively. Middle-agedDgat1-/- mice exhibited several features associated with longevity, including decreased levels of circulating insulin growth factor 1 (IGF1) and reduced fecundity. Thus, deletion of DGAT1 in mice provides a model of leanness and extended lifespan that is independent of calorie restriction.

Diet-induced obesity (DIO) leads to inflammatory activation of macrophages in white adipose tissue (WAT) and subsequently to insulin resistance. PPARγ agonists are antidiabetic agents known to suppress inflammatory macrophage activation and to induce expression of the triacylglycerol (TG) synthesis enzyme acyl CoA: diacylglycerol acyltransferase 1 (DGAT1) in WAT and in adipocytes. Here, we investigated in mice the relationship between macrophage lipid storage capacity and DIO-associated inflammatory macrophage activation. Mice overexpressing DGAT1 in both macrophages and adipocytes (referred to herein as aP2-Dgat1 mice) were more prone to DIO but were protected against inflammatory macrophage activation, macrophage accumulation in WAT, systemic inflammation, and insulin resistance. To assess the contribution of macrophage DGAT1 expression to this phenotype, we transplanted wild-type mice with aP2-Dgat1 BM. These mice developed DIO similar to that of control mice but retained the protection from WAT inflammation and insulin resistance seen in aP2-Dgat1 mice. In isolated macrophages, Dgat1 mRNA levels correlated directly with TG storage capacity and inversely with inflammatory activation by saturated fatty acids (FAs). Moreover, PPARγ agonists increased macrophage Dgat1 mRNA levels, and the protective effects of these agonists against FA-induced inflammatory macrophage activation were absent in macrophages isolated from Dgat1-null mice. Thus, increasing DGAT1 expression in murine macrophages increases their capacity for TG storage, protects against FA-induced inflammatory activation, and is sufficient to reduce the inflammatory and metabolic consequences of DIO., Introduction Chronic diet-induced obesity (DIO) promotes infiltration of the white adipose tissue (WAT) by monocyte-derived phagocytic and antigen-presenting cells that include macrophages and dendritic cells. These macrophages accumulate in crown-like [...]

Mice lacking acyl-CoA:diacylglycerol acyltransferase 1 (DGAT1), an enzyme that catalyzes the terminal step in triacylglycerol synthesis, have enhanced insulin sensitivity and are protected from obesity, a result of increased energy expenditure. In these mice, factors derived from white adipose tissue (WAT) contribute to the systemic changes in metabolism. One such factor, adiponectin, increases fatty acid oxidation and enhances insulin sensitivity. To test the hypothesis that adiponectin is required for the altered energy and glucose metabolism in DGAT1-deficient mice, we generated adiponectin-deficient mice and introduced adiponectin deficiency into DGAT1-deficient mice by genetic crosses. Although adiponectin-deficient mice fed a high-fat diet were heavier, exhibited worse glucose tolerance, and had more hepatic triacylglycerol accumulation than wild-type controls, mice lacking both DGAT1 and adiponectin, like DGAT1-deficient mice, were protected from diet-induced obesity, glucose intolerance, and hepatic steatosis. These findings indicate that adiponectin is required for normal energy, glucose, and lipid metabolism but that the metabolic changes induced by DGAT1-deficient WAT are independent of adiponectin and are likely due to other WAT-derived factors. Our findings also suggest that the pharmacological inhibition of DGAT1 may be useful for treating human obesity and insulin resistance associated with low circulating adiponectin levels. triglyceride; adipose tissue; gene knockout; acyl-coenzyme A:diacylglycerol acyltransferase 1 doi:10.1152/ajpendo.00621.2005

Research shows that the physiological mechanism which governs insulin action on glucose breakdown and movement in rats is stereoselective. The R-(+) sterioisomer of the antioxidant alpha-lipoic acid lowers the level of plasma insulin and free fatty acids in obese Zucker rats while the S-(-) sterioisomer of alpha-lipoic acid actively inhibits insulin activity.

Reports that three insulin response sequences (IRS) in the glucose-6-phosphatase catalytic subunit gene promoter are functionally distinct. Maximum repression of basal glucose-6-phosphatase catalytic subunit gene transcription by insulin; Accessory factor to enhance the effect of insulin; Chromatin immuno-precipitation assays; Inhibitory effect of insulin on the expression of a heterologous fusion gene.

Background: Growth Differentiation Factor 15 (GDF15), a divergent member of the TGF-β superfamily, signals via the hindbrain glial-derived neurotrophic factor receptor alpha-like and rearranged during transfection receptor co-receptor (GFRAL-RET) complex. In nonclinical species, GDF15 is a potent anorexigen leading to substantial weight loss. MBL949 is a half-life extended recombinant human GDF15 dimer., Methods: MBL949 was evaluated in multiple nonclinical species and then in humans in two randomized and placebo-controlled clinical trials. In the Phase 1 first-in-human, single ascending dose trial MBL949 or placebo was injected subcutaneously to overweight and obese healthy volunteers (n=65) at doses ranging from 0.03 to 20 mg. In Phase 2, MBL949 or placebo was administered subcutaneously every other week for a total of 8 doses to obese participants (n=126) in five different dose regimens predicted to be efficacious based on data from the Phase 1 trial., Results: In nonclinical species, MBL949 was generally safe and effective with reduced food intake and body weight in mice, rats, dogs, and monkeys. Weight loss was primarily from reduced fat, and metabolic endpoints improved. A single ascending dose study in overweight or obese healthy adults demonstrated mean terminal half-life of 18-22 days, and evidence of weight loss at the higher doses. In the Phase 2, weight loss was minimal following biweekly dosing of MBL949 for 14 weeks. MBL949 was safe and generally tolerated in humans over the dose range tested, adverse events of the gastrointestinal system were the most frequent observed., Conclusion: The prolonged half-life of MBL949 supports biweekly dosing in patients. MBL949 had an acceptable safety profile. The robust weight loss observed in nonclinical species did not translate to weight loss efficacy in humans., Trial Registration: ClinicalTrials.gov NCT05199090., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Endocrine Society. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com. See the journal About page for additional terms.)