DGAT1 participates in the effect of HNF4A on hepatic secretion of triglyceride-rich lipoproteins

Sergey Krapivner, Maria Jesus Iglesias, Angela Silveira, Jesper Tegner, Johan Björkegren, Anders Hamsten, M. Van't Hooft*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

11 Scopus citations

Abstract

Objective-: Hepatocyte nuclear factor-4α (HNF4A) is a transcription factor that influences plasma triglyceride metabolism via an as of yet unknown mechanism. In this study, we searched for the critical protein that mediates this effect using different human model systems.Methods and results-: Up-and downregulation of HNF4A in human hepatoma Huh7 and HepG2 cells was associated with marked changes in the secretion of triglyceride-rich lipoproteins (TRLs). Short interfering RNA (siRNA) inhibition of HNF4A influenced the expression of several genes, including acyl-CoA:diacylglycerol acyltransferase 1 (DGAT1). siRNA knockdown of DGAT1 reduced DGAT1 activity and decreased the secretion of TRLs. No additive effects of combined siRNA inhibition of HNF4A and DGAT1 were found on the secretion of TRLs, whereas the increase in TRL secretion induced by HNF4A overexpression was largely abolished by DGAT1 siRNA inhibition. A putative binding site for HNF4A was defined by in silico and in vitro methods. HNF4A and DGAT1 expressions were analyzed in 80 human liver samples, and significant relationships were observed between HNF4A and DGAT1 mRNA levels (r=0.50, P<0.0001) and between DGAT1 mRNA levels and plasma triglyceride concentration (r=0.09, P<0.01). Conclusion-: This study identified DGAT1 as an important protein that participates in the effect of HNF4A on hepatic secretion of TRLs.

Original languageEnglish (US)
Pages (from-to)962-967
Number of pages6
JournalArteriosclerosis, Thrombosis, and Vascular Biology
Volume30
Issue number5
DOIs
StatePublished - May 1 2010

Keywords

  • Gene expression
  • Lipoproteins
  • Liver
  • Metabolism
  • Transcription

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine

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