Atrial fibroblast-derived exosomal miR-21 upregulate myocardial KCa3.1 via the PI3K-Akt pathway during rapid pacing
Fu Yuntao,
Liang Jinjun,
Liu Hua Fen,
Chen Huiyu,
Liu Dishiwen,
Cao Zhen,
Youcheng Wang,
Xuewen Wang,
Yuanjia Ke,
Cheng Yanni,
Guo Kexin,
Peng Zhibin,
Yang Mei,
Qingyan Zhao
Affiliations
Fu Yuntao
Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China; Cardiovascular Research Institute, Wuhan University, Wuhan, China; Hubei Key Laboratory of Cardiology, Wuhan, China
Liang Jinjun
Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China; Cardiovascular Research Institute, Wuhan University, Wuhan, China; Hubei Key Laboratory of Cardiology, Wuhan, China
Liu Hua Fen
Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China; Cardiovascular Research Institute, Wuhan University, Wuhan, China; Hubei Key Laboratory of Cardiology, Wuhan, China
Chen Huiyu
Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China; Cardiovascular Research Institute, Wuhan University, Wuhan, China; Hubei Key Laboratory of Cardiology, Wuhan, China
Liu Dishiwen
Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China; Cardiovascular Research Institute, Wuhan University, Wuhan, China; Hubei Key Laboratory of Cardiology, Wuhan, China
Cao Zhen
Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China; Cardiovascular Research Institute, Wuhan University, Wuhan, China; Hubei Key Laboratory of Cardiology, Wuhan, China
Youcheng Wang
Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China; Cardiovascular Research Institute, Wuhan University, Wuhan, China; Hubei Key Laboratory of Cardiology, Wuhan, China
Xuewen Wang
Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China; Cardiovascular Research Institute, Wuhan University, Wuhan, China; Hubei Key Laboratory of Cardiology, Wuhan, China
Yuanjia Ke
Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China; Cardiovascular Research Institute, Wuhan University, Wuhan, China; Hubei Key Laboratory of Cardiology, Wuhan, China
Cheng Yanni
Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China; Cardiovascular Research Institute, Wuhan University, Wuhan, China; Hubei Key Laboratory of Cardiology, Wuhan, China
Guo Kexin
Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China; Cardiovascular Research Institute, Wuhan University, Wuhan, China; Hubei Key Laboratory of Cardiology, Wuhan, China
Peng Zhibin
Yidu People's Hospital, Hubei, China
Yang Mei
Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China; Cardiovascular Research Institute, Wuhan University, Wuhan, China; Hubei Key Laboratory of Cardiology, Wuhan, China; Corresponding author. Mei Yang, Cardiovascular Research Institute of Wuhan University, Renmin Hospital of Wuhan University, 238 Jiefang Road, Wuhan, China.
Qingyan Zhao
Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China; Cardiovascular Research Institute, Wuhan University, Wuhan, China; Hubei Key Laboratory of Cardiology, Wuhan, China; Corresponding author. Cardiovascular Research Institute of Wuhan University, Renmin Hospital of Wuhan University, 238 Jiefang Road, Wuhan, China.
Background: Fibroblast-derived exosomes can regulate the electrical remodeling of cardiomyocytes, and the intermediate-conductance calcium-activated potassium channel (KCa3.1) is important in atrial electrical remodeling. However, the underlying molecular mechanisms remain unclear. This study aimed to investigate the regulation of cardiac electrophysiology by exosomes linked to KCa3.1. Methods: Atrial myocytes (AMs) and atrial fibroblasts were isolated from Sprague-Dawley suckling rats and cultured individually. The cellular atrial fibrillation (AF) model was established via electrical stimulation (1.0 v/cm, 10 Hz), and fibroblast-derived exosomes were isolated via ultracentrifugation. Exosomes were co-cultured with AMs to investigate their influences on KCa3.1 and the underlying mechanisms. Nanoparticle tracking analysis and transmission electron microscopy were used to measure exosome particle sizes and concentrations. Whole-cell patch clamp was applied to record the current density of KCa3.1 and action potential duration (APD). The expression of miR-21-5p was detected by reverse-transcription polymerase chain reaction (RT-PCR). Western blotting or immunofluorescence was used to measure the expression of exosomal markers, Akt phosphorylation, and KCa3.1. Results: Rapid pacing promoted the secretion of exosomes from atrial fibroblasts and miR-21-5p expression in atrial fibroblasts and exosomes. KCa3.1 protein expression and current density significantly increased, and APD50 and APD90 were sharply shortened after rapid pacing in AMs. TRAM-34 (KCa3.1 blocker) extended APD and reduced susceptibility to AF. KCa3.1 and P-AKT expressions were amplified after co-culturing AMs with exosomes secreted by atrial fibroblasts. In contrast, the increase in KCa3.1 expression was reversed after the cells were co-cultured with exosomes secreted by atrial fibroblasts that were transfected with miR-21-5p inhibitors or after the use of LY294002, a PI3K/Akt pathway inhibitor. Conclusions: Rapid pacing promoted the secretion of exosomes from fibroblasts, and miR-21-5p was upregulated in exosomes. Moreover, the miR-21-5p-enriched exosomes upregulated KCa3.1 expression in AMs via the PI3K/Akt pathway.
