Modulation of angiotensin II-mediated hypertension and cardiac remodeling by lectin-like oxidized low-density lipoprotein receptor-1 deletion

Hypertension. 2008 Sep;52(3):556-62. doi: 10.1161/HYPERTENSIONAHA.108.115287. Epub 2008 Jul 21.

Abstract

Angiotensin II via type 1 receptor activation upregulates the expression of lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1), and LOX-1 activation, in turn, upregulates angiotensin II type 1 receptor expression. We postulated that interruption of this positive feedback loop might attenuate the genesis of angiotensin II-induced hypertension and subsequent cardiac remodeling. To examine this postulate, LOX-1 knockout and wild-type mice were infused with angiotensin II or norepinephrine (control for angiotensin II) for 4 weeks. Angiotensin II-, but not norepinephrine-, induced hypertension was attenuated in LOX-1 knockout mice. Angiotensin II-induced cardiac remodeling was also attenuated in LOX-1 knockout mice. Importantly, angiotensin II type 1 receptor expression was reduced, and the expression and activity of endothelial NO synthase were preserved in the tissues of LOX-1 knockout mice given angiotensin II. Reactive oxygen species generation, nicotinamide-adenine dinucleotide phosphate oxidase expression, and phosphorylation of p38 and p44/42 mitogen-activated protein kinases were also much less pronounced in the LOX-1 knockout mice given angiotensin II. These alterations in biochemical and structural abnormalities were associated with preservation of cardiac hemodynamics in the LOX-1 knockout mice. To confirm that fibroblast function is modulated in the absence of LOX-1, cardiac fibroblasts from wild-type and LOX-1 knockout mice were treated with angiotensin II. Indeed, LOX-1 knockout mice cardiac fibroblasts revealed an attenuated profibrotic response on treatment with angiotensin II. These observations provide strong evidence that LOX-1 is a key modulator of the development of angiotensin II-induced hypertension and subsequent cardiac remodeling.

Publication types

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

MeSH terms

  • Angiotensin II / pharmacology*
  • Animals
  • Blood Pressure / drug effects
  • Cells, Cultured
  • Fibroblasts / cytology
  • Fibroblasts / physiology
  • Gene Deletion
  • Gene Expression / drug effects
  • Gene Expression / physiology
  • Hypertension / metabolism*
  • Hypertension / physiopathology*
  • Mice
  • Mice, Knockout
  • Myocardium / cytology
  • Myocardium / metabolism
  • Nitric Oxide Synthase Type II / genetics
  • Nitric Oxide Synthase Type III
  • Norepinephrine / metabolism
  • Norepinephrine / pharmacology
  • Oxidative Stress / drug effects
  • Oxidative Stress / physiology
  • Receptor, Angiotensin, Type 1 / genetics
  • Scavenger Receptors, Class E / genetics*
  • Scavenger Receptors, Class E / metabolism
  • Vasoconstrictor Agents / pharmacology*
  • Ventricular Remodeling / physiology*

Substances

  • Receptor, Angiotensin, Type 1
  • Scavenger Receptors, Class E
  • Vasoconstrictor Agents
  • Angiotensin II
  • Nitric Oxide Synthase Type II
  • Nitric Oxide Synthase Type III
  • Nos3 protein, mouse
  • Norepinephrine