RhoA guanine exchange factor expression profile in arteries: evidence for a Rho kinase-dependent negative feedback in angiotensin II-dependent hypertension

Am J Physiol Cell Physiol. 2012 May 1;302(9):C1394-404. doi: 10.1152/ajpcell.00423.2011. Epub 2012 Feb 8.

Abstract

Sustained overactivation of RhoA is a common component for the pathogenesis of several cardiovascular disorders, including hypertension. Although activity of Rho proteins depends on Rho exchange factors (Rho-GEFs), the identity of Rho-GEFs expressed in vascular smooth muscle cells (VSMC) and participating in the control of Rho protein activity and Rho-dependent functions remains unknown. To address this question, we analyzed by quantitative RT-PCR the expression profile of 28 RhoA-GEFs in arteries of normotensive (saline-treated) and hypertensive (ANG II-treated) rats. Sixteen RhoA-GEFs were downregulated in mesenteric arteries of hypertensive rats, among which nine are also downregulated in cultured VSMC stimulated by ANG II (100 nM, 48 h), suggesting a direct effect of ANG II. Inhibition of type 1 ANG II receptors (losartan, 1 μM) or Rho kinase (fasudil, 10 μM) prevented ANG II-induced RhoA-GEF downregulation. Functionally, ANG II-induced downregulation of RhoA-GEFs is associated with decreased Rho kinase activation in response to endothelin-1, norepinephrine, and U-46619. This work thus identifies a group of RhoA-GEFs that controls RhoA and RhoA-dependent functions in VSMC, and a negative feedback of RhoA/Rho kinase activity on the expression of these RhoA-GEFs that may play an adaptative role to limit RhoA/Rho kinase activation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Angiotensin II / metabolism
  • Angiotensin II / toxicity
  • Animals
  • Arteries / metabolism
  • Blotting, Western
  • Feedback, Physiological / physiology*
  • Gene Expression Profiling
  • Guanine Nucleotide Exchange Factors / biosynthesis*
  • Hypertension / chemically induced
  • Hypertension / physiopathology*
  • Male
  • Muscle, Smooth, Vascular / metabolism*
  • Muscle, Smooth, Vascular / physiopathology
  • RNA, Small Interfering
  • Rats
  • Rats, Inbred WKY
  • Real-Time Polymerase Chain Reaction
  • Reverse Transcriptase Polymerase Chain Reaction
  • Signal Transduction / physiology
  • Transfection
  • rho-Associated Kinases / metabolism*

Substances

  • Guanine Nucleotide Exchange Factors
  • RNA, Small Interfering
  • Angiotensin II
  • rho-Associated Kinases