Endothelin-1, via ETA receptor and independently of transforming growth factor-beta, increases the connective tissue growth factor in vascular smooth muscle cells

Circ Res. 2005 Jul 22;97(2):125-34. doi: 10.1161/01.RES.0000174614.74469.83. Epub 2005 Jun 23.

Abstract

Endothelin (ET)-1 is a potent vasoconstrictor that participates in cardiovascular diseases. Connective tissue growth factor (CTGF) is a novel fibrotic mediator that is overexpressed in human atherosclerotic lesions, myocardial infarction, and experimental models of hypertension. In vascular smooth muscle cells (VSMCs), CTGF regulates cell proliferation/apoptosis, migration, and extracellular matrix (ECM) accumulation. Our aim was to investigate whether ET-1 could regulate CTGF and to investigate the potential role of ET-1 in vascular fibrosis. In growth-arrested rat VSMCs, ET-1 upregulated CTGF mRNA expression, promoter activity, and protein production. The blockade of CTGF by a CTGF antisense oligonucleotide decreased FN and type I collagen expression in ET-1-treated cells, showing that CTGF participates in ET-1-induced ECM accumulation. The ETA, but not ETB, antagonist diminished ET-1-induced CTGF expression gene and production. Several intracellular signals elicited by ET-1, via ETA receptors, are involved in CTGF synthesis, including activation of RhoA/Rho-kinase and mitogen-activated protein kinase and production of reactive oxygen species. CTGF is a mediator of TGF-beta- and angiotensin (Ang) II-induced fibrosis. In VSMCs, ET-1 did not upregulate TGF-beta gene or protein. The presence of neutralizing transforming growth factor (TGF)-beta antibody did not modify ET-1-induced CTGF production, showing a TGF-beta-independent regulation. We have also found an interrelationship between Ang II and ET-1 because the ETA antagonist diminished CTGF upregulation caused by Ang II. Collectively, our results show that, in cultured VSMCs, ET-1, independently of TGF-beta and through the activation of several intracellular signals via ETA receptors, regulates CTGF. This novel finding suggests that CTGF could be a mediator of the profibrotic effects of ET-1 in vascular diseases.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 1,2-Dihydroxybenzene-3,5-Disulfonic Acid Disodium Salt / pharmacology
  • Angiotensin I / pharmacology
  • Animals
  • Cells, Cultured
  • Connective Tissue Growth Factor
  • Endothelin-1 / pharmacology*
  • Extracellular Matrix Proteins / metabolism
  • Extracellular Signal-Regulated MAP Kinases / physiology
  • Gene Expression Regulation / drug effects*
  • Immediate-Early Proteins / analysis
  • Immediate-Early Proteins / genetics*
  • Intercellular Signaling Peptides and Proteins / analysis
  • Intercellular Signaling Peptides and Proteins / genetics*
  • Muscle, Smooth, Vascular / metabolism*
  • Promoter Regions, Genetic
  • RNA, Messenger / analysis
  • Rats
  • Rats, Inbred WKY
  • Receptor, Endothelin A / physiology*
  • Transforming Growth Factor beta / physiology*
  • rhoA GTP-Binding Protein / physiology

Substances

  • CCN2 protein, human
  • CCN2 protein, rat
  • Endothelin-1
  • Extracellular Matrix Proteins
  • Immediate-Early Proteins
  • Intercellular Signaling Peptides and Proteins
  • RNA, Messenger
  • Receptor, Endothelin A
  • Transforming Growth Factor beta
  • Connective Tissue Growth Factor
  • 1,2-Dihydroxybenzene-3,5-Disulfonic Acid Disodium Salt
  • Angiotensin I
  • Extracellular Signal-Regulated MAP Kinases
  • rhoA GTP-Binding Protein