Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2007 Oct 23;104(43):17075-80.
doi: 10.1073/pnas.0707060104. Epub 2007 Oct 16.

Mitochondrial dysfunction due to long-chain Acyl-CoA dehydrogenase deficiency causes hepatic steatosis and hepatic insulin resistance

Dongyan Zhang  1 , Zhen-Xiang Liu, Cheol Soo Choi, Liqun Tian, Richard Kibbey, Jianying Dong, Gary W Cline, Philip A Wood, Gerald I Shulman
Affiliations

Mitochondrial dysfunction due to long-chain Acyl-CoA dehydrogenase deficiency causes hepatic steatosis and hepatic insulin resistance

Dongyan Zhang et al. Proc Natl Acad Sci U S A. .

Abstract

Alterations in mitochondrial function have been implicated in the pathogenesis of insulin resistance and type 2 diabetes. However, it is unclear whether the reduced mitochondrial function is a primary or acquired defect in this process. To determine whether primary defects in mitochondrial beta-oxidation can cause insulin resistance, we studied mice with a deficiency of long-chain acyl-CoA dehydrogenase (LCAD), a key enzyme in mitochondrial fatty acid oxidation. Here, we show that LCAD knockout mice develop hepatic steatosis, which is associated with hepatic insulin resistance, as reflected by reduced insulin suppression of hepatic glucose production during a hyperinsulinemic-euglycemic clamp. The defects in insulin action were associated with an approximately 40% reduction in insulin-stimulated insulin receptor substrate-2-associated phosphatidylinositol 3-kinase activity and an approximately 50% decrease in Akt2 activation. These changes were associated with increased PKCepsilon activity and an aberrant 4-fold increase in diacylglycerol content after insulin stimulation. The increase in diacylglycerol concentration was found to be caused by de novo synthesis of diacylglycerol from medium-chain acyl-CoA after insulin stimulation. These data demonstrate that primary defects in mitochondrial fatty acid oxidation capacity can lead to diacylglycerol accumulation, PKCepsilon activation, and hepatic insulin resistance.

PubMed Disclaimer

Conflict of interest statement

The authors declare no conflict of interest.

Figures

Fig. 1.
Fig. 1.
Whole-body glucose metabolism and insulin signaling in WT (open bars) and LCAD−/− (filled bars) mice during the hyperinsulinemic-euglycemic clamp. (A) Glucose infusion rate averaged for the last 30 min of the clamp. (B) Whole-body glucose disposal rate during the clamp. (C) Suppression of hepatic glucose production during the clamp. (D) Rate of insulin-stimulated muscle glucose uptake. (E) Liver IRS2 tyrosine phosphorylation. (F) Liver PI3-kinase activity. (G) Liver Akt2 activity. (H) Muscle IRS-1-associated PI3-kinase activity.
Fig. 2.
Fig. 2.
Hepatic insulin resistance in LCAD−/− mice is associated with increased insulin-stimulated diacylglycerol content and PKCε membrane translocation. (A) Liver diacylglycerol content at basal fasting condition. (B) Liver diacylglycerol content after the hyperinsulinemic-euglycemic clamp. (C) Western blot analysis of basal liver cytosolic and membranal PKCε. (D) Western blot analysis of cytosolic and membranal PKCε in livers of mice after clamp.
Fig. 3.
Fig. 3.
Profile and contents of acyl-CoA, diacylglycerol and triglyceride in liver and muscle. (A) Liver fasting acyl-CoA profile. (B) Liver diacylglycerol profile after insulin clamp. A, E, S, O, L, and P denote arachidonoyl, eicosa pentanoyl, stearoyl, oleoyl, linoleoyl, and palmitoyl groups, respectively. (C) Acyl-CoA profile after insulin clamp. (D) Acyl-CoA content. (E) Triglyceride content.
Fig. 4.
Fig. 4.
Schematic diagram of oleic acid metabolism in liver of WT and LCAD−/− mice. (A) During fasting, WT mice have high mitochondrial oleic acid oxidation and relatively lower peroxisomal and microsomal fatty acid oxidation. (B) During fasting, LCAD−/− mice have reduced mitochondrial oleic acid oxidation at the level of 5-tetradecenoyl-CoA, which accumulates and is partially oxidized by peroxisomal and microsomal oxidation. (C) Fed WT mice convert extra oleic acid to triglyceride. (D) Fed LCAD−/− mice convert the accumulated 5-tetradecenoyl-CoA to diacylglycerol. ER, endoplasmic reticulum; ACS, acyl-CoA synthetase; VLCAD, very long chain acyl-CoA dehydrogenase; AOX, acyl-CoA oxidase; TG, triglyceride; DAG, diacylglyerol; LPA, lysophosphatidic acid; DGAT, diacylglycerol acyl transferase; AGPAT, acylglycerol phosphate acyl transferase; GPAT, glycerol phosphate acyl transferase.
Fig. 5.
Fig. 5.
Indirect calorimetry measurement during a 24-h period. (A) Percentage of whole-body fatty acid oxidation (derived from the measured value of respiratory quotient). (B) Physical activity. (C) Energy expenditure. (D) Oxygen consumption. (E) Food intake.
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Petersen KF, Befroy D, Dufour S, Dziura J, Ariyan C, Rothman DL, DiPietro L, Cline GW, Shulman GI. Science. 2003;300:1140–1142. - PMC - PubMed
    1. Mootha VK, Bunkenborg J, Olsen JV, Hjerrild M, Wisniewski JR, Stahl E, Bolouri MS, Ray HN, Sihag S, Kamal M, et al. Cell. 2003;115:629–640. - PubMed
    1. Patti ME, Butte AJ, Crunkhorn S, Cusi K, Berria R, Kashyap S, Miyazaki Y, Kohane I, Costello M, Saccone R, et al. Proc Natl Acad Sci USA. 2003;100:8466–8471. - PMC - PubMed
    1. Kelly DP, Scarpulla RC. Genes Dev. 2004;18:357–368. - PubMed
    1. Petersen KF, Dufour S, Befroy D, Garcia R, Shulman GI. N Engl J Med. 2004;350:664–671. - PMC - PubMed

Publication types

MeSH terms

LinkOut - more resources