Adenovirus-mediated transfer of a gene encoding cholesterol 7α-hydroxylase into hamsters increases hepatic enzyme activity and reduces plasma total and low density lipoprotein cholesterol

David K. Spady, Jennifer A. Cuthbert, Maureen N. Willard, Robert S. Meidell

Research output: Contribution to journalArticle

94 Scopus citations

Abstract

Clinical interventions that accelerate conversion of cholesterol to bile acids reduce circulating low density lipoprotein (LDL) cholesterol concentrations. The initial and rate-limiting step in the bile acid biosynthetic pathway is catalyzed by hepatic cholesterol 7α-hydroxylase. To examine the effects of transient primary overexpression of this enzyme on sterol metabolism and lipoprotein transport, we constructed a recombinant adenovirus in which a cDNA encoding rat 7α-hydroxylase is expressed from the human cytomegalovirus immediate-early promoter (AdCMVTα). Syrian hamsters administered AdCMVTα intravenously accumulated transgene-specific mRNA in the liver and demonstrated a dose-dependent increase in hepatic microsomal 7α-hydroxylase activity. The increased conversion of cholesterol to bile acids resulted in a compensatory increase in hepatic cholesterol synthesis. In addition, overexpression of 7α-hydroxylase reduced the rate of LDL cholesterol entry into the plasma space and, in animals maintained on a Western-type diet, restored hepatic LDL receptor expression. As a consequence, plasma LDL concentrations fell by -60% in animals maintained on control diet and by -75% in animals consuming a Western-type diet. Plasma high density lipoprotein cholesterol levels were reduced to a lesser degree. These results demonstrate that transient upregulation of bile acid synthesis by direct transfer of a 7α-hydroxylase gene favorably alters circulating lipoprotein profiles and suggest one potential molecular target for genetic strategies aimed at reducing cardiovascular risk.

Original languageEnglish (US)
Pages (from-to)700-709
Number of pages10
JournalJournal of Clinical Investigation
Volume96
Issue number2
Publication statusPublished - Aug 1995

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Keywords

  • Bile acids
  • Cholesterol
  • Genes
  • Lipoprotein
  • Viruses

ASJC Scopus subject areas

  • Medicine(all)

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