Endothelin-1, via ETA receptor and independently of transforming growth factor-beta, increases the connective tissue growth factor in vascular smooth muscle cells.
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.
Vascular and Renal Research Laboratory, Fundación Jiménez Díaz, Universidad Autónoma Madrid, Avda. Reyes Católicos, 2, 28040 Madrid, Spain.
Juan
J
Rodriguez-Vita
Marta
M
Ruiz-Ortega
Mónica
M
Rupérez
Vanessa
V
Esteban
Elsa
E
Sanchez-López
Juan José
JJ
Plaza
Jesús
J
Egido
D014013:1,2-Dihydroxybenzene-3,5-Disulfonic Acid Disodium Salt / Q000494:pharmacology; D000803:Angiotensin I / Q000494:pharmacology; D000818:Animals; D002478:Cells, Cultured; D055513:Connective Tissue Growth Factor; D019332:Endothelin-1 / Q000494:pharmacology*; D016326:Extracellular Matrix Proteins / Q000378:metabolism; D048049:Extracellular Signal-Regulated MAP Kinases / Q000502:physiology; D005786:Gene Expression Regulation / Q000187:drug effects*; D017874:Immediate-Early Proteins / Q000032:analysis / Q000235:genetics*; D036341:Intercellular Signaling Peptides and Proteins / Q000032:analysis / Q000235:genetics*; D009131:Muscle, Smooth, Vascular / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D011921:Rats, Inbred WKY; D044022:Receptor, Endothelin A / Q000502:physiology*; D016212:Transforming Growth Factor beta / Q000502:physiology*; D020742:rhoA GTP-Binding Protein / Q000502:physiology
C526317:CCN2 protein, human; C526316:CCN2 protein, rat; D019332:Endothelin-1; D016326:Extracellular Matrix Proteins; D017874:Immediate-Early Proteins; D036341:Intercellular Signaling Peptides and Proteins; D012333:RNA, Messenger; D044022:Receptor, Endothelin A; D016212:Transforming Growth Factor beta; D055513:Connective Tissue Growth Factor; D014013:1,2-Dihydroxybenzene-3,5-Disulfonic Acid Disodium Salt; D000803:Angiotensin I; D048049:Extracellular Signal-Regulated MAP Kinases; D020742:rhoA GTP-Binding Protein