Role of caveolin-1 in atrial fibrillation as an anti-fibrotic signaling molecule in human atrial fibroblasts.
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ABSTRACT: Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia in the general population; yet, the precise mechanisms resulting in AF are not fully understood. Caveolin-1 (Cav-1), the principal structural component of caveolae organelles in cardiac fibroblasts, is involved in several cardiovascular conditions; however, the study on its function in atrium, in particular, in AF, is still lacking. This report examines the hypothesis that Cav-1 confers an anti-AF effect by mediating atrial structural remodeling through its anti-fibrotic action. We evaluated the expression of Cav-1, transforming growth factor-?1 (TGF-?1), and fibrosis in atrial specimens of 13 patients with AF and 10 subjects with sinus rhythm, and found that the expression of Cav-1 was significantly downregulated, whereas TGF-?1 level, collagens I/III contents and atrial fibrosis were markedly increased, in AF. Western blot analysis demonstrated that treatment of human atrial fibroblasts (HAFs) with TGF-?1 resulted in a concentration- and time-dependent repression of Cav-1. Downregulation of Cav-1 with siRNA increased the TGF-?1-induced activation of Smad signal pathway and collagens production in HAFs. Furthermore, incubation of HAFs with the peptides derived from Cav-1 to achieve Cav-1 gain-of-function abolished the TGF-?1-induced production of collagens I/III and decreases of MMP-2/-9 expression. Therefore it was concluded that Cav-1 is an important anti-AF signaling mediator by conferring its anti-fibrotic effects in atrium.
SUBMITTER: Yi SL
PROVIDER: S-EPMC3891766 | biostudies-literature | 2014
REPOSITORIES: biostudies-literature
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