Hepatic low-density lipoprotein receptor-related protein deficiency in mice increases atherosclerosis independent of plasma cholesterol

Blood. 2004 May 15;103(10):3777-82. doi: 10.1182/blood-2003-11-4051. Epub 2004 Jan 22.

Abstract

The low-density lipoprotein (LDL) receptor-related protein (LRP) has a well-established role in the hepatic removal of atherogenic apolipoprotein E (APOE)-rich remnant lipoproteins from plasma. In addition, LRP recognizes multiple distinct pro- and antiatherogenic ligands in vitro. Here, we investigated the role of hepatic LRP in atherogenesis independent of its role in removal of APOE-rich remnant lipoproteins. Mice that allow inducible inactivation of hepatic LRP were combined with LDL receptor and APOE double-deficient mice (MX1Cre(+)LRP(flox/flox)LDLR(-/-)APOE(-/-)). On an LDLR(-/-)APOE(-/-) background, hepatic LRP deficiency resulted in decreased plasma cholesterol and triglycerides (cholesterol: 17.1 +/- 5.2 vs 23.4 +/- 6.3 mM, P =.025; triglycerides: 1.1 +/- 0.5 vs 2.2 +/- 0.8 mM, P =.002, for MX1Cre(+)LRP(flox/flox)-LDLR(-/-)APOE(-/-) and control LRP(flox/flox)-LDLR(-/-)APOE(-/-) mice, respectively). Lower plasma cholesterol in MX1Cre(+)LRP(flox/flox)-LDLR(-/-)APOE(-/-) mice coincided with increased plasma lipoprotein lipase (71.2 +/- 7.5 vs 19.1 +/- 2.4 ng/ml, P =.002), coagulation factor VIII (4.4 +/- 1.1 vs 1.9 +/- 0.5 U/mL, P =.001), von Willebrand factor (2.8 +/- 0.6 vs 1.4 +/- 0.3 U/mL, P =.001), and tissue-type plasminogen activator (1.7 +/- 0.7 vs 0.9 +/- 0.5 ng/ml, P =.008) compared with controls. Strikingly, MX1Cre(+)LRP(flox/flox)LDLR(-/-)APOE(-/-) mice showed a 2-fold higher atherosclerotic lesion area compared with controls (408.5 +/- 115.1 vs 219.1 +/- 86.0 10(3)microm(2), P =.003). Our data indicate that hepatic LRP plays a clear protective role in atherogenesis independent of plasma cholesterol, possibly due to maintaining low levels of its proatherogenic ligands.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Aorta / chemistry
  • Apolipoproteins E / deficiency
  • Arteriosclerosis / blood
  • Arteriosclerosis / etiology*
  • Arteriosclerosis / pathology
  • Blood Coagulation Factors / analysis
  • Cholesterol / blood*
  • Lipids / blood
  • Liver / chemistry*
  • Low Density Lipoprotein Receptor-Related Protein-1 / deficiency*
  • Low Density Lipoprotein Receptor-Related Protein-1 / physiology
  • Male
  • Mice
  • Mice, Knockout
  • Mice, Transgenic
  • Receptors, LDL / deficiency

Substances

  • Apolipoproteins E
  • Blood Coagulation Factors
  • Lipids
  • Low Density Lipoprotein Receptor-Related Protein-1
  • Receptors, LDL
  • Cholesterol