Patatin-like phospholipase domain-containing 3 (PNPLA3) I148M (rs738409) affects hepatic VLDL secretion in humans and in vitro
Journal article, 2012

Background & Aims: The robust association between non-alcoholic fatty liver disease (NAFLD) and the genetic variant I148M (rs738409) in PNPLA3 has been widely replicated. The aim of this study was to investigate the effect of the PNPLA3 I148M mutation on: (1) hepatic secretion of very low density lipoproteins (VLDL) in humans; and (2) secretion of apolipoprotein B (apoB) from McA-RH 7777 cells, which secrete VLDL-sized apoB-containing lipoproteins. Methods: VLDL kinetics was analyzed after a bolus infusion of stable isotopes in 55 overweight/obese men genotyped for the PNPLA3 I148M variant. Intracellular lipid content, apoB secretion and glycerolipid metabolism were studied in McA-RH 7777 cells overexpressing the human 1481 wild type or 148M mutant PNPLA3 protein. Results: In humans, carriers of the PNPLA3 148M allele had increased liver fat compared to 1481 homozygotes, and kinetic analysis showed a relatively lower secretion of the large, triglyceride-rich VLDL (VLDL1) in 148M carriers vs. 1481 homozygotes for the same amount of liver fat. McA-RH 7777 cells overexpressing the 148M mutant protein showed a higher intracellular triglyceride content with a lower apoB secretion and fatty acid efflux, compared to cells overexpressing the 1481 wild type protein. The responses with 148M matched those observed in cells expressing the empty vector, indicating that the mutation results in loss of function. Conclusions: We have shown that PNPLA3 affects the secretion of apoB-containing lipoproteins both in humans and in vitro and that the 148M protein is a loss-of-function mutation. We propose that PNPLA3 148M promotes intracellular lipid accumulation in the liver by reducing the lipidation of VLDL.

Patatin-like phospholipase domain-containing 3



VLDL secretion

Genetic variant

fatty liver-disease


low-density lipoprotein

obese subjects

Liver fat content

b-containing lipoproteins


triglyceride hydrolysis



Carlo Pirazzi

University of Gothenburg

Martin Adiels

University of Gothenburg

Chalmers, Mathematical Sciences

Maria A Burza

University of Gothenburg

Rosellina Margherita Mancina

University of Gothenburg

Max Levin

University of Gothenburg

Marcus Ståhlman

University of Gothenburg

M. R. Taskinen

M. Orho-Melander

Jeanna Perman

University of Gothenburg

A. Pujia

Linda Andersson

University of Gothenburg

Cristina Maglio

University of Gothenburg

T. Montalcini

Olov Wiklund

University of Gothenburg

Jan Borén

University of Gothenburg

Stefano Romeo

University of Gothenburg

Journal of Hepatology

0168-8278 (ISSN) 1600-0641 (eISSN)

Vol. 57 6 1276-1282

Subject Categories

Cardiac and Cardiovascular Systems



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