Novel Rho/MRTF/SRF inhibitors block matrix-stiffness and TGF-β-induced fibrogenesis in human colonic myofibroblasts

Inflamm Bowel Dis. 2014 Jan;20(1):154-65. doi: 10.1097/01.MIB.0000437615.98881.31.

Abstract

Background: Ras homolog gene family, member A (RhoA)/Rho-associated coiled-coil forming protein kinase signaling is a key pathway in multiple types of solid organ fibrosis, including intestinal fibrosis. However, the pleiotropic effects of RhoA/Rho-associated coiled-coil forming protein kinase signaling have frustrated targeted drug discovery efforts. Recent recognition of the role of Rho-regulated gene transcription by serum response factor (SRF) and its transcriptional cofactor myocardin-related transcription factor A (MRTF-A) suggest a novel locus for pharmacological intervention.

Methods: Because RhoA signaling is mediated by both physical and biochemical stimuli, we examined whether pharmacological inhibition of RhoA or the downstream transcription pathway of MRTF-A/SRF could block intestinal fibrogenesis in 2 in vitro models.

Results: In this study, we demonstrate that inhibition of RhoA signaling blocks both matrix-stiffness and transforming growth factor beta-induced fibrogenesis in human colonic myofibroblasts. Repression of alpha-smooth muscle actin and collagen expression was associated with the inhibition of MRTF-A nuclear localization. CCG-1423, a first-generation Rho/MRTF/SRF pathway inhibitor, repressed fibrogenesis in both models, yet has unacceptable cytotoxicity. Novel second-generation inhibitors (CCG-100602 and CCG-203971) repressed both matrix-stiffness and transforming growth factor beta-mediated fibrogenesis as determined by protein and gene expression in a dose-dependent manner.

Conclusions: Targeting the Rho/MRTF/SRF mechanism with second-generation Rho/MRTF/SRF inhibitors may represent a novel approach to antifibrotic therapeutics.

Publication types

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

MeSH terms

  • Anilides / pharmacology*
  • Benzamides / pharmacology*
  • Blotting, Western
  • Cell Adhesion / drug effects
  • Cell Nucleus / drug effects
  • Cell Nucleus / metabolism
  • Cells, Cultured
  • Colon / drug effects*
  • Colon / metabolism
  • Colon / pathology
  • DNA-Binding Proteins / antagonists & inhibitors*
  • DNA-Binding Proteins / metabolism
  • Extracellular Matrix / drug effects
  • Extracellular Matrix / metabolism
  • Fibrosis / metabolism
  • Fibrosis / pathology
  • Fibrosis / prevention & control*
  • Humans
  • Myofibroblasts / drug effects*
  • Myofibroblasts / metabolism
  • Myofibroblasts / pathology
  • Oncogene Proteins, Fusion / antagonists & inhibitors*
  • Oncogene Proteins, Fusion / metabolism
  • RNA, Messenger / genetics
  • Real-Time Polymerase Chain Reaction
  • Reverse Transcriptase Polymerase Chain Reaction
  • Serum Response Factor / antagonists & inhibitors*
  • Serum Response Factor / metabolism
  • Signal Transduction / drug effects
  • Trans-Activators
  • Transforming Growth Factor beta / genetics
  • Transforming Growth Factor beta / metabolism*
  • rho GTP-Binding Proteins / antagonists & inhibitors*
  • rho GTP-Binding Proteins / metabolism

Substances

  • Anilides
  • Benzamides
  • CCG 1423
  • DNA-Binding Proteins
  • MRTFA protein, human
  • Oncogene Proteins, Fusion
  • RNA, Messenger
  • Serum Response Factor
  • Trans-Activators
  • Transforming Growth Factor beta
  • rho GTP-Binding Proteins