The involvement of transforming growth factor-beta1 secretion in urotensin II-induced collagen synthesis in neonatal cardiac fibroblasts.

Abstract

As the most potent vasoconstrictor in mammals, urotensin II (U II) has recently been demonstrated to play an important role in adverse cardiac remodeling and fibrosis. However, the mechanisms of U II-induced myocardial fibrosis remain to be clarified. We postulated that U II alters transforming growth factor-beta1 (TGF-beta1) expression, and thereby modulates cardiac fibroblast collagen metabolism. Experiments were conducted using cardiac fibroblast from neonatal Wistar rats to determine the expression of TGF-beta1, and the role of U II receptor UT in this process. The functional role of TGF-beta1 and UT in modulating U II effects on type I, III collagen mRNA expression and 3H-proline incorporation was also analyzed. TGF-beta1 gene and protein expression were consistently identified in quiescent cardiac fibroblasts. U II increased the expression of TGF-beta1 mRNA and protein in a time-dependent manner. This effect was UT mediated, because UT antagonist urantide abolished U II-induced TGF-beta1 expression. U II-induced increase in type I, III collagen mRNA expression and 3H-proline incorporation were both inhibited by a specific TGF-beta1 neutralizing antibody and UT receptor antagonist urantide. Hence, our results indicate that TGF-beta1 is upregulated in cardiac fibroblasts by U II via UT and modulates profibrotic effects of U II. These findings provide novel insights into U II-induced cardiac remodeling.

• Authors: Hong-Yan Dai, Wei-Qiang Kang, Xu Wang, Xiao-Jing Yu, Zhen-Hua Li, Meng-Xiong Tang, Dong-Ling Xu, Chen-Wen Li, Yun Zhang, Zhi-Ming Ge
• Journal: Regulatory peptides (Regul Pept) Vol. 140 Issue 1-2 Pg. 88-93 (Apr 05 2007) ISSN: 0167-0115 [Print] Netherlands
• PMID: 17188370 (Publication Type: Journal Article)

Chemical References

• Peptide Fragments
• RNA, Messenger
• Receptors, G-Protein-Coupled
• Transforming Growth Factor beta1
• Urotensins
• urotensin II (4-11), Pen(5)-Trp(7)-Orn(8)-
• Collagen
• urotensin II

Topics

• Animals
• Animals, Newborn
• Cells, Cultured
• Collagen (metabolism)
• Fibroblasts (cytology, drug effects, metabolism)
• Gene Expression (drug effects)
• Myocardium (cytology, metabolism)
• Peptide Fragments (pharmacology)
• RNA, Messenger (genetics, metabolism)
• Rats
• Rats, Wistar
• Receptors, G-Protein-Coupled (antagonists & inhibitors, metabolism)
• Reverse Transcriptase Polymerase Chain Reaction
• Transforming Growth Factor beta1 (genetics, metabolism)
• Urotensins (pharmacology)