p63RhoGEF regulates auto- and paracrine signaling in cardiac fibroblasts

J Mol Cell Cardiol. 2015 Nov:88:39-54. doi: 10.1016/j.yjmcc.2015.09.009. Epub 2015 Sep 21.


Cardiac remodeling, a hallmark of heart disease, is associated with intense auto- and paracrine signaling leading to cardiac fibrosis. We hypothesized that the specific mediator of Gq/11-dependent RhoA activation p63RhoGEF, which is expressed in cardiac fibroblasts, plays a role in the underlying processes. We could show that p63RhoGEF is up-regulated in mouse hearts subjected to transverse aortic constriction (TAC). In an engineered heart muscle model (EHM), p63RhoGEF expression in cardiac fibroblasts increased resting and twitch tensions, and the dominant negative p63ΔN decreased both. In an engineered connective tissue model (ECT), p63RhoGEF increased tissue stiffness and its knockdown as well as p63ΔN reduced stiffness. In 2D cultures of neonatal rat cardiac fibroblasts, p63RhoGEF regulated the angiotensin II (Ang II)-dependent RhoA activation, the activation of the serum response factor, and the expression and secretion of the connective tissue growth factor (CTGF). All these processes were inhibited by the knockdown of p63RhoGEF or by p63ΔN likely based on their negative influence on the actin cytoskeleton. Moreover, we show that p63RhoGEF also regulates CTGF in engineered tissues and correlates with it in the TAC model. Finally, confocal studies revealed a closely related localization of p63RhoGEF and CTGF in the trans-Golgi network.

Keywords: Cardiac remodeling; Connective tissue growth factor; RhoA; p63RhoGEF.

Publication types

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

MeSH terms

  • Actin Cytoskeleton / metabolism
  • Actin Cytoskeleton / ultrastructure
  • Angiotensin II / genetics
  • Angiotensin II / metabolism
  • Animals
  • Animals, Newborn
  • Aorta / surgery
  • Autocrine Communication / genetics
  • Connective Tissue Growth Factor / genetics*
  • Connective Tissue Growth Factor / metabolism
  • Constriction
  • Female
  • Fibroblasts / metabolism*
  • Fibroblasts / pathology
  • Fibroblasts / ultrastructure
  • Gene Expression Regulation
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Models, Cardiovascular
  • Myocardium / metabolism*
  • Myocardium / pathology
  • Paracrine Communication / genetics
  • Rats
  • Rats, Wistar
  • Rho Guanine Nucleotide Exchange Factors / genetics*
  • Rho Guanine Nucleotide Exchange Factors / metabolism
  • Serum Response Factor / genetics*
  • Serum Response Factor / metabolism
  • Signal Transduction
  • Ventricular Remodeling
  • rhoA GTP-Binding Protein / genetics*
  • rhoA GTP-Binding Protein / metabolism
  • trans-Golgi Network / metabolism
  • trans-Golgi Network / ultrastructure


  • CCN2 protein, rat
  • GEFT protein, mouse
  • Rho Guanine Nucleotide Exchange Factors
  • Serum Response Factor
  • Angiotensin II
  • Connective Tissue Growth Factor
  • rhoA GTP-Binding Protein