Axl mediates vascular remodeling induced by deoxycorticosterone acetate-salt hypertension

Hypertension. 2007 Dec;50(6):1057-62. doi: 10.1161/HYPERTENSIONAHA.107.096289. Epub 2007 Oct 8.

Abstract

Axl, a receptor tyrosine kinase, was recently identified as a novel candidate gene in a genetic model of salt-sensitive hypertension (Sabra rat). Our group first reported that Axl plays a significant role in vascular remodeling in response to injury. Here we investigated the role of Axl in the pathogenesis of hypertension in a deoxycorticosterone acetate (DOCA)-salt model. Hypertension was induced in Axl wild-type (Axl(+/+)) mice and Axl-deficient (Axl(-/-)) mice by uninephrectomy and DOCA-salt for 6 weeks. Controls were uninephrectomized and received tap water and regular chow ad libitum. DOCA-salt treatment increased systolic blood pressure by 25 mm Hg in both genotypes after 1 week. Systolic blood pressure remained significantly elevated in Axl(+/+) DOCA, whereas systolic blood pressure levels in Axl(-/-) DOCA mice were the same as controls at 6 weeks. DOCA-salt increased relative kidney weight and glomerular hypertrophy by 40% compared with controls in both genotypes. Consistent with levels of systolic blood pressure, endothelium-dependent vasorelaxation was impaired in Axl(+/+) DOCA mice compared with Axl(+/+) controls, whereas in Axl(-/-) DOCA mice relaxation responses were similar to Axl(-/-) controls. In addition, endothelium-independent vasorelaxation was improved in Axl(-/-) DOCA mice compared with Axl(+/+) DOCA mice. Nitrotyrosine and phospho-Akt immunoreactivity was significantly reduced in arteries from Axl(-/-) DOCA mice compared with Axl(+/+) DOCA mice. The remodeling index of the mesenteric artery (media:lumen ratio) was significantly increased in Axl(+/+) DOCA mice compared with Axl(-/-) DOCA mice. Finally, increased vascular apoptosis in the Axl(-/-) DOCA mice suggests a likely mechanism for Axl-dependent effects on hypertension. These data strengthen the pathogenic role for Axl in salt-sensitive hypertension.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Aorta / physiopathology
  • Apoptosis
  • Axl Receptor Tyrosine Kinase
  • Blood Vessels / pathology*
  • Desoxycorticosterone / pharmacology*
  • Hypertension / chemically induced
  • Hypertension / drug therapy
  • Hypertension / pathology*
  • Immunohistochemistry
  • Kidney / pathology
  • Mesenteric Arteries / pathology
  • Mice
  • Oncogene Proteins / physiology*
  • Phosphorylation
  • Proto-Oncogene Proteins
  • Receptor Protein-Tyrosine Kinases / physiology*
  • Sodium Chloride / pharmacology*
  • Systole / drug effects
  • Vasoconstriction / drug effects

Substances

  • Oncogene Proteins
  • Proto-Oncogene Proteins
  • Desoxycorticosterone
  • Sodium Chloride
  • Receptor Protein-Tyrosine Kinases
  • Axl Receptor Tyrosine Kinase
  • AXL receptor tyrosine kinase, mouse