Chronic overexpression of PNPLA3 I148M in mouse liver causes hepatic steatosis

John Zhong Li, Yongcheng Huang, Ruchan Karaman, Pavlina T. Ivanova, H. Alex Brown, Thomas Roddy, Jose Castro-Perez, Jonathan C. Cohen, Helen H. Hobbs

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153 Scopus citations

Abstract

A genetic variant in PNPLA3 (PNPLA3 I148M), a triacylglycerol (TAG) hydrolase, is a major risk factor for non-alcoholic fatty liver disease (NAFLD); however, the mechanism underlying this association is not known. To develop an animal model of PNPLA3-induced fatty liver disease, we generated transgenic mice that overexpress similar amounts of wild-type PNPLA3 (PNPLA3 WT) or mutant PNPLA3 (PNPLA3 I148M) either in liver or adipose tissue. Overexpression of the transgenes in adipose tissue did not affect liver fat content. Expression of PNPLA3I 148M, but not PNPLA3 WT, in liver recapitulated the fatty liver phenotype as well as other metabolic features associated with this allele in humans. Metabolic studies provided evidence for 3 distinct alterations in hepatic TAG metabolism in PNPLA3 I148Mtransgenic mice: increased formation of fatty acids and TAG, impaired hydrolysis of TAG, and relative depletion of TAG long-chain polyunsaturated fatty acids. These findings suggest that PNPLA3 plays a role in remodeling TAG in lipid droplets, as they accumulate in response to food intake, and that the increase in hepatic TAG levels associated with the I148M substitution results from multiple changes in hepatic TAG metabolism. The development of an animal model that recapitulates the metabolic phenotype of the allele in humans provides a new platform in which to elucidate the role of PNLPA3 I148M in NAFLD.

Original languageEnglish (US)
Pages (from-to)4130-4144
Number of pages15
JournalJournal of Clinical Investigation
Volume122
Issue number11
DOIs
StatePublished - Nov 1 2012

ASJC Scopus subject areas

  • Medicine(all)

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    Li, J. Z., Huang, Y., Karaman, R., Ivanova, P. T., Brown, H. A., Roddy, T., Castro-Perez, J., Cohen, J. C., & Hobbs, H. H. (2012). Chronic overexpression of PNPLA3 I148M in mouse liver causes hepatic steatosis. Journal of Clinical Investigation, 122(11), 4130-4144. https://doi.org/10.1172/JCI65179