Activation of TGF-β1/α-SMA/Col I Profibrotic Pathway in Fibroblasts by Galectin-3 Contributes to Atrial Fibrosis in Experimental Models and Patients

• Published in: Cellular physiology and biochemistry Vol. 47; no. 2; pp. 851 - 863
• Main Authors: Shen, Hua, Wang, Jing, Min, Jie, Xi, Wang, Gao, Yang, Yin, Liang, Yu, Yue, Liu, Kai, Xiao, Jian, Zhang, Yu-feng, Wang, Zhi-nong
• Format: Journal Article
• Language: English
• Published: Basel, Switzerland S. Karger AG 01.01.2018; Cell Physiol Biochem Press GmbH & Co KG
• Subjects: Actins - metabolism; Aged; Animals; Atrial fibrillation; Atrial Fibrillation - metabolism; Atrial Fibrillation - pathology; Atrial Fibrillation - veterinary; Cardiac arrhythmia; Cardiomyocytes; Catheters; Collagen Type I - metabolism; Electric Stimulation; Enzymes; Female; Fibroblasts; Fibroblasts - cytology; Fibroblasts - drug effects; Fibroblasts - metabolism; Fibrosis; Galectin 3 - blood; Galectin 3 - genetics; Galectin 3 - metabolism; Galectin 3 - pharmacology; Galectin-3; Growth factors; Heart failure; HL-1 cell; Humans; Laboratory animals; Male; Mice; Middle Aged; Myocardium - metabolism; Myocardium - pathology; Original Paper; Rabbits; Rapid atrial pacing; Rats; Recombinant Proteins - biosynthesis; Recombinant Proteins - genetics; Recombinant Proteins - pharmacology; Respiration, Artificial; Signal Transduction - drug effects; Transforming Growth Factor beta1 - metabolism; United States > US; China; Galectin-3; HL-1 cell; Atrial fibrillation; Rapid atrial pacing; Fibrosis
• ISSN: 1015-8987; 1421-9778
• DOI: 10.1159/000490077

Background/Aims: This study aimed to evaluate whether galectin-3 (Gal-3) contributes actively to atrial fibrosis both in patients and experimental atrial fibrillation (AF) models. Methods: Mouse HL-1 cardiomyocytes were subjected to rapid electrical stimulation (RES) to explore Gal-3 expression and secretion levels by western blotting (WB) and enzyme linked immunosorbent assay (ELISA). Neonatal rat cardiac fibroblasts were treated with conditioned culture medium and recombinant human Gal-3 to evaluate the activation of the transforming growth factor (TGF)-β1/α-smooth muscle actin (SMA)/collagen I (Col I) profibrotic pathway (WB) and fibroblast proliferation with a Cell Counting Kit-8 (CCK-8). Furthermore, in the rapid atrial pacing (RAP) rabbit AF model, atrial Gal-3 expression and its effects on the profibrotic pathway were evaluated (WB and Masson’s trichrome staining). Moreover, 44 consecutive patients who underwent single mitral valve repair/replacement were included, consisting of 28 patients with persistent AF (PeAF) and 16 with sinus rhythm (SR). Coronary sinus blood was also sampled to test circulating Gal-3 levels (ELISA), and atrial myocardium Gal-3 and its downstream TGF-β1/α-SMA pathway were also measured by WB and immunohistochemical staining. Results: Gal-3 expression in HL-1 cells and its secretion level in culture medium were greatly increased after 24 h RES. Treatment of neonatal rat cardiac fibroblasts with conditioned media collected from the RES group or recombinant human Gal-3 protein (10 and 30 µg/mL) for 72 h induced the activation of the TGF-β1/α-SMA/Col I profibrotic pathway. RAP increased Gal-3 levels and activated the TGF-β1/α-SMA/Col I pathway in rabbit left atria, while the Gal-3 inhibitor N-acetyllactosamine, injected at 4.5 mg/kg every 3 days, mitigated these adverse changes. Furthermore, Gal-3 levels in coronary sinus blood samples and myocardial Gal-3 expression levels were higher in the PeAF patients than in the SR patients, and higher level profibrotic pathway activation was also confirmed. Conclusions: Activation of Gal-3 expression in the atria can subsequently activate the TGF-β1/α-SMA/Col I pathway in cardiac fibroblasts, which may enhance atrial fibrosis.