Cited by 356Metabolism, Diabetes, and CancerAdipose Tissue and MetabolismLipid metabolism and biosynthesis

Upregulation of myocellular DGAT1 augments triglyceride synthesis in skeletal muscle and protects against fat-induced insulin resistance

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Liu, Li, Zhang, Yiying, Chen, Nancy, Shi, Xiaojing, Tsang, Bonny, Yu, Yi-Hao·2007·Journal of Clinical Investigation

Abstract

Increased fat deposition in skeletal muscle is associated with insulin resistance. However, exercise increases both intramyocellular fat stores and insulin sensitivity, a phenomenon referred to as "the athlete's paradox". In this study, we provide evidence that augmenting triglyceride synthesis in skeletal muscle is intrinsically connected with increased insulin sensitivity. Exercise increased diacylglycerol (DAG) acyltransferase (DGAT) activity in skeletal muscle. Channeling fatty acid substrates into TG resulted in decreased DAG and ceramide levels. Transgenic overexpression of DGAT1 in mouse skeletal muscle replicated these findings and protected mice against high-fat diet-induced insulin resistance. Moreover, in isolated muscle, DGAT1 deficiency exacerbated insulin resistance caused by fatty acids, whereas DGAT1 overexpression mitigated the detrimental effect of fatty acids. The heightened insulin sensitivity in the transgenic mice was associated with attenuated fat-induced activation of DAG-responsive PKCs and the stress mediator JNK1. Consistent with these changes, serine phosphorylation of insulin receptor substrate 1 was reduced, and Akt activation and glucose 4 membrane translocation were increased. In conclusion, upregulation of DGAT1 in skeletal muscle is sufficient to recreate the athlete's paradox and illustrates a mechanism of exercise-induced enhancement of muscle insulin sensitivity. Thus, increasing muscle DGAT activity may offer a new approach to prevent and treat insulin resistance and type 2 diabetes mellitus.

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  • In muscle-specific DGAT1-overexpressing mice, increased DGAT activity raised IMTG levels.

    “In these mice, increased DGAT activity in muscle resulted in higher IMTG levels, decreased DAG and ceramide levels, and resistance to diet-induced glucose intolerance.”
  • In those mice, increased DGAT activity conferred resistance to diet-induced glucose intolerance.

    “In these mice, increased DGAT activity in muscle resulted in higher IMTG levels, decreased DAG and ceramide levels, and resistance to diet-induced glucose intolerance.”
  • In those mice, increased DGAT activity decreased DAG and ceramide levels.

    “In these mice, increased DGAT activity in muscle resulted in higher IMTG levels, decreased DAG and ceramide levels, and resistance to diet-induced glucose intolerance.”
  • The concentration of intramuscular triglycerides, fatty acyl-CoAs, DAG, and/or ceramide is elevated in skeletal muscle from obese humans, genetically obese rats, and high-fat-diet-fed obese mice in association with insulin resistance.

    “The concentration of IMTG, fatty acyl-CoAs, DAG, and/or ceramide are elevated in skeletal muscle from obese humans, genetically obese rats, and HFD-fed, obese mice in association with insulin resistance (53)(54)(55)(56)(57).”
  • Muscle-specific overexpression of Dgat1 and an acute bout of exercise prevent high-fat-diet- and lipid-induced impairments in insulin action together with increased intramuscular triglyceride synthesis, decreased DAG and ceramide accumulation, and reduced activation of nPKC/cPKC, JNK, and/or IKK/NF-κB.

    “To this end, muscle-specific overexpression of Dgat1 as well as an acute bout of exercise (which increases mitochondrial GPAT and DGAT1 abundance) prevents HFD-and lipid-induced impairments in insulin action in conjunction with increased IMTG synthesis and decreased DAG and ceramide accumulation as well as reduced activation of nPKC/cPKC, JNK, and/or”

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Research works printed but not linked: 1

  1. Listenberger, L.L., et al. 2003. Triglyceride accumu- lation protects against fatty acid-induced lipotoxic- ity. Proc. Natl. Acad. Sci. U. S. A. 100:3077-3082.

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Authors
Liu, L., Zhang, Y., Chen, N., Shi, X., Tsang, B., & Yu, Y.-H.
Affiliations
  • Columbia University (US)
  • Columbia University Irving Medical Center (US)
Corresponding author
Yu, Yi-Hao
Venue
Journal of Clinical Investigation
Published
2007-06-01
Volume
117
Issue
6
Pages
1679-1689
ISSN
0021-9738 (ISSN-L)
OpenAlex
W2142416266
Cited by
356
References
84
Citations by year
2026: 3 · 2025: 5 · 2024: 6 · 2023: 14 · 2022: 9 · 2021: 9 · 2020: 19 · 2019: 8 · 2018: 13 · 2017: 16 · 2016: 19 · 2015: 18 · 2014: 27 · 2013: 31 · 2012: 33
FWCI
12.44
Type
journal article
Language
en
Open access
Locations
  • Journal of Clinical Investigation (publishedVersion)
  • Europe PMC (PubMed Central) (publishedVersion)
  • PubMed Central (publishedVersion)
  • PubMed (publishedVersion)
Funders
  • National Institutes of Health
  • National Heart, Lung, and Blood Institute (HL073029, R01HL073029)
  • National Institute of Diabetes and Digestive and Kidney Diseases (DK-60530, DK063034, R01DK063034, K08DK060530, DK071866, R03DK071866)
Topics
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Metabolism, Diabetes, and Cancer
  • Health Sciences › Medicine › Physiology › Adipose Tissue and Metabolism
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Biochemistry › Lipid metabolism and biosynthesis
Keywords
DGAT1, diacylglycerol acyltransferase, triglyceride synthesis, skeletal muscle, insulin resistance, physical activity, ceramide, diacylglycerol, protein kinase C, JNK1, IRS-1, Akt signaling, glucose uptake, type 2 diabetes, high-fat diet
MeSH terms
Animals, Base Sequence, Diabetes Mellitus, Type 2, Dietary Fats, Physical Exertion, Humans, Insulin Resistance, Male, Mice, Inbred C57BL, Mice, Transgenic, Triglycerides, Up-Regulation, DNA Primers, Mice, Knockout, Muscle, Skeletal, Diacylglycerol O-Acyltransferase, Mice

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