CGI-58 knockdown sequesters diacylglycerols in lipid droplets/ER-preventing diacylglycerol-mediated hepatic insulin resistance.

Détails

ID Serval
serval:BIB_22209C120A1B
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Titre
CGI-58 knockdown sequesters diacylglycerols in lipid droplets/ER-preventing diacylglycerol-mediated hepatic insulin resistance.
Périodique
Proceedings of the National Academy of Sciences of the United States of America
Auteur(s)
Cantley J.L., Yoshimura T., Camporez J.P., Zhang D., Jornayvaz F.R., Kumashiro N., Guebre-Egziabher F., Jurczak M.J., Kahn M., Guigni B.A., Serr J., Hankin J., Murphy R.C., Cline G.W., Bhanot S., Manchem V.P., Brown J.M., Samuel V.T., Shulman G.I.
ISSN
1091-6490 (Electronic)
ISSN-L
0027-8424
Statut éditorial
Publié
Date de publication
2013
Peer-reviewed
Oui
Volume
110
Numéro
5
Pages
1869-1874
Langue
anglais
Résumé
Comparative gene identification 58 (CGI-58) is a lipid droplet-associated protein that promotes the hydrolysis of triglyceride by activating adipose triglyceride lipase. Loss-of-function mutations in CGI-58 in humans lead to Chanarin-Dorfman syndrome, a condition in which triglyceride accumulates in various tissues, including the skin, liver, muscle, and intestines. Therefore, without adequate CGI-58 expression, lipids are stored rather than used for fuel, signaling intermediates, and membrane biosynthesis. CGI-58 knockdown in mice using antisense oligonucleotide (ASO) treatment also leads to severe hepatic steatosis as well as increased hepatocellular diacylglycerol (DAG) content, a well-documented trigger of insulin resistance. Surprisingly, CGI-58 knockdown mice remain insulin-sensitive, seemingly dissociating DAG from the development of insulin resistance. Therefore, we sought to determine the mechanism responsible for this paradox. Hyperinsulinemic-euglycemic clamp studies reveal that the maintenance of insulin sensitivity with CGI-58 ASO treatment could entirely be attributed to protection from lipid-induced hepatic insulin resistance, despite the apparent lipotoxic conditions. Analysis of the cellular compartmentation of DAG revealed that DAG increased in the membrane fraction of high fat-fed mice, leading to PKCε activation and hepatic insulin resistance. However, DAG increased in lipid droplets or lipid-associated endoplasmic reticulum rather than the membrane of CGI-58 ASO-treated mice, and thus prevented PKCε translocation to the plasma membrane and induction of insulin resistance. Taken together, these results explain the disassociation of hepatic steatosis and DAG accumulation from hepatic insulin resistance in CGI-58 ASO-treated mice, and highlight the importance of intracellular compartmentation of DAG in causing lipotoxicity and hepatic insulin resistance.
Mots-clé
1-Acylglycerol-3-Phosphate O-Acyltransferase/genetics, 1-Acylglycerol-3-Phosphate O-Acyltransferase/metabolism, Adipose Tissue, White/drug effects, Adipose Tissue, White/metabolism, Animals, Cell Membrane/drug effects, Cell Membrane/metabolism, Diet, High-Fat, Diglycerides/metabolism, Endoplasmic Reticulum/drug effects, Endoplasmic Reticulum/metabolism, Gene Expression/drug effects, Gene Knockdown Techniques, Humans, Immunoblotting, Injections, Intraperitoneal, Insulin Resistance, Lipids/chemistry, Liver/drug effects, Liver/metabolism, Male, Mice, Mice, Inbred C57BL, Oligonucleotides, Antisense/administration & dosage, Oligonucleotides, Antisense/genetics, Protein Kinase C-epsilon/metabolism, Protein Transport/drug effects, Reverse Transcriptase Polymerase Chain Reaction
Pubmed
Web of science
Création de la notice
10/09/2015 13:08
Dernière modification de la notice
03/03/2018 14:48
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