Knockdown of Hepatic ABCA1 by RNA Interference Decreases Plasma HDL Cholesterol Levels and Influences Postprandial Lipemia in Mice

Arterioscler Thromb Vasc Biol. 2005 Jul;25(7):1433-8. doi: 10.1161/01.ATV.0000166616.86723.d0. Epub 2005 Apr 21.

Abstract

Objective: To investigate the impact of hepatic ABCA1 on systemic lipoprotein metabolism in vivo by an adenovirus-mediated RNA interference approach.

Methods and results: Efficiency of plasmid-based small interference RNA (siRNA)-induced knockdown of cotransfected murine ATP binding cassette transporter A1 (mABCA1) in HEK-293 cells was judged by RT-polymerase chain reaction, immunofluorescence, and Western blot analysis. The most effective plasmid was used to generate a recombinant adenovirus as a tool to selectively downregulate ABCA1 expression in mouse liver (C57BL/6). In comparison to controls, Western blot analysis from liver membrane proteins of Ad-anti-ABCA1 infected mice resulted in an approximately 50% reduction of endogenous ABCA1 and a clear upregulation of apolipoprotein E. Fast protein liquid chromatography analysis of plasma revealed that hepatic ABCA1 protein reduction was associated with an approximately 40% decrease of HDL cholesterol and a reduction of HDL-associated apolipoprotein A-I and E. In the fasted state, other lipoprotein classes were not affected. To analyze the influence of ABCA1 downregulation on postprandial lipemia, infected mice were given a gastric load of radiolabeled trioleate in olive oil. In Ad-anti-ABCA1 infected mice, the postprandial increase of chylomicrons and chylomicron-associated apolipoproteins B and E was significantly reduced as compared with controls.

Conclusions: Hepatic ABCA1 contributes to HDL plasma levels and influences postprandial lipemia.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • ATP Binding Cassette Transporter 1
  • ATP-Binding Cassette Transporters / genetics*
  • ATP-Binding Cassette Transporters / metabolism*
  • Adenoviridae / genetics
  • Animals
  • Carcinoma, Hepatocellular
  • Cell Line, Tumor
  • Cholesterol, HDL / blood*
  • Dietary Fats / pharmacokinetics
  • Humans
  • Hyperlipidemias / metabolism*
  • Hyperlipidemias / physiopathology*
  • Kidney / cytology
  • Liver / metabolism
  • Liver Neoplasms
  • Mice
  • Mice, Inbred C57BL
  • Postprandial Period
  • RNA Interference
  • Triglycerides / blood

Substances

  • ABCA1 protein, human
  • ATP Binding Cassette Transporter 1
  • ATP-Binding Cassette Transporters
  • Cholesterol, HDL
  • Dietary Fats
  • Triglycerides