Nutrition and Health Sciences, Department of

 

Authors

Soonkyu Chung, Department of Food Science and Human Nutrition, University of Florida, Gainesville, FLFollow
Jenelle M. Timmins, Department of Pathology/Section on Lipid Sciences, Wake Forest University Health Sciences, Winston-Salem, North Carolina
MyNgan Duong, Department of Pathology/Section on Lipid Sciences, Wake Forest University Health Sciences, Winston-Salem, North Carolina
Chiara Degirolamo, Department of Pathology/Section on Lipid Sciences, Wake Forest University Health Sciences, Winston-Salem, North Carolina
Shunxing Rong, Department of Pathology/Section on Lipid Sciences, Wake Forest University Health Sciences, Winston-Salem, North Carolina
Janet K. Sawyer, Department of Pathology/Section on Lipid Sciences, Wake Forest University Health Sciences, Winston-Salem, North Carolina
Roshni R. Singaraja, Centre for Molecular Medicine and Therapeutics, University of British Columbia, Vancouver, British Columbia
Michael R. Hayden, Centre for Molecular Medicine and Therapeutics, University of British Columbia, Vancouver, British Columbia
Nobuyo Maeda, Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, North Carolina
Lawrence L. Rudel, Department of Pathology/Section on Lipid Sciences, Wake Forest University Health Sciences, Winston-Salem, North Carolina
Gregory S. Shelness, Department of Pathology/Section on Lipid Sciences, Wake Forest University Health Sciences, Winston-Salem, North Carolina
John S. Parks, Department of Pathology/Section on Lipid Sciences, Wake Forest University Health Sciences, Winston-Salem, North CarolinaFollow

Date of this Version

2010

Citation

J Biol Chem. 2010 Apr 16; 285(16): 12197–12209.

Comments

Copyright © 2010 by The American Society for Biochemistry and Molecular Biology, Inc.

Abstract

Loss of ABCA1 activity in Tangier disease (TD) is associated with abnormal apoB lipoprotein (Lp) metabolism in addition to the complete absence of high density lipoprotein (HDL). We used hepatocyte-specific ABCA1 knock-out (HSKO) mice to test the hypothesis that hepatic ABCA1 plays dual roles in regulating Lp metabolism and nascent HDL formation. HSKO mice recapitulated the TD lipid phenotype with postprandial hypertriglyceridemia, markedly decreased LDL, and near absence of HDL. Triglyceride (TG) secretion was 2-fold higher in HSKO compared with wild type mice, primarily due to secretion of larger TG-enriched VLDL secondary to reduced hepatic phosphatidylinositol 3-kinase signaling. HSKO mice also displayed delayed clearance of postprandial TG and reduced post-heparin plasma lipolytic activity. In addition, hepatic LDLr expression and plasma LDL catabolism were increased 2-fold in HSKO compared with wild type mice. Last, adenoviral repletion of hepatic ABCA1 in HSKO mice normalized plasma VLDL TG and hepatic phosphatidylinositol 3-kinase signaling, with a partial recovery of HDL cholesterol levels, providing evidence that hepatic ABCA1 is involved in the reciprocal regulation of apoB Lp production and HDL formation. These findings suggest that altered apoB Lp metabolism in TD subjects may result from hepatic VLDL TG overproduction and increased hepatic LDLr expression and highlight hepatic ABCA1 as an important regulatory factor for apoB-containing Lp metabolism.

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