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EXTRACELLULAR MATRIX, CELL INTERACTIONS
Departments of 1Medicine and 2Pharmacology and 3Biomedical Sciences PhD Program, University of California, San Diego, School of Medicine, La Jolla, California
Submitted 2 June 2008 ; accepted in final form 13 February 2009
The ability of adenosine (ADO) to inhibit proliferation and protein synthesis (in particular, collagen synthesis) in cardiac fibroblasts (CF) may ameliorate adverse cardiac remodeling and fibrosis seen in heart failure patients. However, little is known about the signaling pathways that ADO may modulate in CF to alter cell phenotype. Accordingly, this study was designed to identify ADO receptors (AR) and the signaling pathways linked to them in primary cultures of adult rat CF. Quantitative RT-PCR data indicate that the mRNAs for all four known ARs (A1R, A2aR, A2bR, and A3R) are present in rat CF, with a greater prevalence of A2 receptor subtypes. No coupling of AR to the Gq-phospholipase C signaling pathway or to mobilization of calcium is measurable. Studies using subtype specific agents imply that the A2aR and A2bR couple to Gs-adenylyl cyclase and A1R couple weakly to Gi-adenylyl cyclase. 2-Chloroadenosine, 5'-N-ethylcarboxamidoadensoine, and other agents that elevate cellular cAMP stimulate extracellular signal-regulated kinase 1/2 activity in a pertussis toxin-insensitive manner. We conclude that a combination of cAMP-dependent signals generated via A2a and A2b receptors likely mediate ADO signaling in adult rat CF.
G protein-linked receptors;extracellular matrix; myocardial fibrosis
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F. Villarreal, S. A. Epperson, I. Ramirez-Sanchez, K. G. Yamazaki, and L. L. Brunton Regulation of cardiac fibroblast collagen synthesis by adenosine: roles for Epac and PI3K Am J Physiol Cell Physiol, May 1, 2009; 296(5): C1178 - C1184. [Abstract] [Full Text] [PDF] |
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