Inhibition of cardiac fibroblast proliferation and myofibroblast differentiation by resveratrol
ABSTRACT Cardiac fibroblasts (CFs) regulate myocardial remodeling by proliferating, differentiating, and secreting extracellular matrix proteins. Prolonged activation of CFs leads to cardiac fibrosis and reduced myocardial contractile function. Resveratrol (RES) exhibits a number of cardioprotective properties; however, the possibility that this compound affects CF function has not been considered. The current study tests whether RES directly influences the growth and proliferation of CFs and differentiation to the hypersecretory myofibroblast phenotype. Pretreatment of CFs with RES (5-25 microM) inhibited basal and ANG II-induced extracellular signal-regulated kinase (ERK) 1/2 and ERK kinase activation. This inhibition by RES reduced basal proliferation and blocked ANG II-induced growth and proliferation of CFs in a concentration-dependent manner, as measured by [(3)H]leucine and [(3)H]thymidine incorporation, respectively. RES pretreatment attenuated ERK phosphorylation when CFs were stimulated with 0.2 nM epidermal growth factor (EGF), a concentration at which EGF-induced ERK activation over basal was similar to the phosphorylation induced by 100 nM ANG II. Akt phosphorylation in CFs was unaffected by treatment with either 100 nM ANG II or 25 microM RES. Pretreatment of CFs with RES also reduced both ANG II- and transforming growth factor-beta-induced CF differentiation to the myofibroblast phenotype, indicated by a reduction in alpha-smooth muscle actin expression and stress fiber organization in CFs. This study identifies RES as an anti-fibrotic agent in the myocardium by limiting CF proliferation and differentiation, two critical steps in the pathogenesis of cardiac fibrosis.
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ABSTRACT: Atrial fibrosis is an important factor in initiating and maintaining atrial fibrillation. The purpose of this study was to test the hypothesis that atrial angiotensin-converting enzyme-2 (ACE2) overexpression might inhibit atrial collagen accumulation and improve atrial remodeling in a canine atrial pacing model. Thirty-two mongrel dogs of both genders were divided randomly into 4 groups: sham-operated, control, gene therapy with adenovirus-enhanced green fluorescent protein (Ad-EGFP), and gene therapy with Ad-ACE2. All of the dogs in the control, Ad-EGFP, and Ad-ACE2 groups were paced at 450 bpm for a period of 14 days. The dogs in the sham group were instrumented without pacing. After 2 weeks, all of the dogs underwent a thoracotomy operation and received epicardial gene painting. On post-gene transfer day 21, the animals underwent electrophysiology, histology, and molecular studies. The percentage of fibrosis in the Ad-ACE2 group was markedly lower than the percentage in the control and Ad-EGFP groups. Compared with the other groups, ACE2 expression was increased significantly in the Ad-ACE2 group. Compared with the sham and Ad-ACE2 groups, the expression levels of transforming growth factor-β1 and Smad3 were significantly higher in the Ad-EGFP and control groups; however, the expression levels of Smad7 were lower in the atrial tissue as detected by Western blot and reverse transcription polymerase chain reaction. Our results demonstrate that the overexpression of ACE2 inhibits atrial collagen accumulation and improves left atrial remodeling and function in a canine model of atrial fibrillation. Thus, targeted gene ACE2 therapy provides a promising approach for the treatment of atrial fibrillation. © 2015 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.Journal of the American Heart Association 01/2015; 4(3). DOI:10.1161/JAHA.114.001530 · 2.88 Impact Factor
Cardiology 12/2014; 130(1):52-53. DOI:10.1159/000369127 · 2.04 Impact Factor
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ABSTRACT: High throughput screening of combinatorial chemical libraries is a powerful approach for identifying targeted molecules. The display of combinatorial peptide libraries on the surface of bacteriophages offers a rapid, economical way to screen billions of peptides for specific binding properties and has impacted fields ranging from cancer to vaccine development. As a modification to this approach, we have previously created a system that enables site-specific insertion of selenocysteine (Sec) residues into peptides displayed pentavalently on M13 phage as pIII coat protein fusions. In this study, we show the utility of selectively derivatizing these Sec residues through the primary amine of small molecules that target a G protein-coupled receptor, the adenosine A1 receptor, leaving the other coat proteins including the major coat protein pVIII unmodified. We further demonstrate that modified Sec-phage with multivalent bound agonist bind to cells and elicit downstream signaling with orders of magnitude greater potency than unconjugated agonist. Our results provide proof of concept of a system that can create hybrid, small-molecule containing peptide libraries and opens up new possibilities for phage-drug therapies.Bioconjugate Chemistry 02/2015; DOI:10.1021/acs.bioconjchem.5b00011 · 4.82 Impact Factor