Hypercholesterolemia in low density lipoprotein receptor knockout mice and its reversal by adenovirus-mediated gene delivery

J Clin Invest. 1993 Aug;92(2):883-93. doi: 10.1172/JCI116663.

Abstract

We employed homologous recombination in embryonic stem cells to produce mice lacking functional LDL receptor genes. Homozygous male and female mice lacking LDL receptors (LDLR-/- mice) were viable and fertile. Total plasma cholesterol levels were twofold higher than those of wild-type litter-mates, owing to a seven- to ninefold increase in intermediate density lipoproteins (IDL) and LDL without a significant change in HDL. Plasma triglyceride levels were normal. The half-lives for intravenously administered 125I-VLDL and 125I-LDL were prolonged by 30-fold and 2.5-fold, respectively, but the clearance of 125I-HDL was normal in the LDLR-/- mice. Unlike wild-type mice, LDLR-/- mice responded to moderate amounts of dietary cholesterol (0.2% cholesterol/10% coconut oil) with a major increase in the cholesterol content of IDL and LDL particles. The elevated IDL/LDL level of LDLR-/- mice was reduced to normal 4 d after the intravenous injection of a recombinant replication-defective adenovirus encoding the human LDL receptor driven by the cytomegalovirus promoter. The virus restored expression of LDL receptor protein in the liver and increased the clearance of 125I-VLDL. We conclude that the LDL receptor is responsible in part for the low levels of VLDL, IDL, and LDL in wild-type mice and that adenovirus-encoded LDL receptors can acutely reverse the hypercholesterolemic effects of LDL receptor deficiency.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Alleles
  • Animals
  • Base Sequence
  • Cholesterol / blood
  • Cholesterol, Dietary
  • Chromosome Mapping
  • Crosses, Genetic
  • Embryo, Mammalian
  • Female
  • Genetic Therapy*
  • Humans
  • Hypercholesterolemia / genetics*
  • Hypercholesterolemia / metabolism
  • Hypercholesterolemia / therapy*
  • Lipoproteins / blood
  • Lipoproteins, IDL
  • Lipoproteins, LDL / blood
  • Lipoproteins, VLDL / blood
  • Liver / metabolism
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Molecular Sequence Data
  • Oligodeoxyribonucleotides
  • Receptors, LDL / analysis
  • Receptors, LDL / genetics*
  • Receptors, LDL / metabolism
  • Recombination, Genetic
  • Restriction Mapping
  • Stem Cells / metabolism

Substances

  • Cholesterol, Dietary
  • Lipoproteins
  • Lipoproteins, IDL
  • Lipoproteins, LDL
  • Lipoproteins, VLDL
  • Oligodeoxyribonucleotides
  • Receptors, LDL
  • Cholesterol