Cardiac Fibroblasts Promote Ferroptosis in Atrial Fibrillation by Secreting Exo-miR-23a-3p Targeting SLC7A11

Abstract

The exact mechanism of atrial fibrillation (AF) has been not well elucidated. Ferroptosis is an iron-dependent cell death due to excessive accumulation of peroxidized polyunsaturated fatty acids. However, the molecular mechanism underlying AF and ferroptosis has never been reported. Here, we established the rapid pacing model in vivo and vitro to investigate the relationship between AF and ferroptosis. In canine model of rapid atrial pacing, the content of malondialdehyde and total ions in the atrial tissue of the Pacing group was significantly increased and the exosome inhibitor GW4869 reduced ferroptosis, fibrosis, and inflammation and improved histological and electrophysiological remodeling. In rapid pacing h9c2 cells, the expression of antioxidative stress genes associated with ferroptosis presented sequential changes and proteins involved in ferroptosis such as FTH1, SLC7A11, and GPX4 were gradually depleted. Furthermore, pacing cardiac fibroblast-derived exosomes (CF-exos) exacerbated ferroptosis in h9c2 cells and pretreated pacing-CF-exos with GW4869 alleviated injury to h9c2 cells. In mechanism, our results demonstrated that pacing-CF-exos highly expressed miR-23a-3p by informatics analysis and experimental verification. Inhibitor-miR-23a-3p protected h9c2 cells from ferroptosis accompanying with upregulation of SLC7A11. In addition, SLC7A11 was shown to be the target gene of miR-23a-3p. In conclusion, our results suggest that CF-exos-miR-23a-3p may promote ferroptosis. The development of AF in a persistent direction could be prevented by intervening with exosomal miRNAs to reduce oxidative stress injury and ferroptosis.

PDE3A and GSK3B as Atrial Fibrillation Susceptibility Genes in the Chinese Population via Bioinformatics and Genome-Wide Association Analysis

“…There are several mechanisms that produce ROS in cardiac myocytes, including mitochondria, NADPH oxidase, uncoupled NO synthase, and xanthine oxidase [ 36 , 37 ], which increase oxidative stress and promote cardiac fibrosis. Many studies have reported that patients with AF have a decrease in antioxidant-related gene expression and an increase in ROS-related gene expression [ 38 ]. Consistent with our pathway enrichment results, previous studies have reported that regulation of oxidative stress-related gene expression was functionally associated with PI3K/AKT signaling, which is a key profibrotic element in various tissues and was reported to be capable of activating atrial fibroblasts to differentiate into myofibroblasts [ 39 ].…”

KCa3.1 promotes exosomes secretion by activating on AKT/Rab27a in atrial myocytes during rapid pacing

“…The mouse atrial HL-1 cell line (Procell, China) or mouse macrophage cell line RAW264.7 (Wuhan University), was cultured using F12/DMEM medium (Gibico, United States) or DMEM (High glucose, Gibico, United States) containing 10% fetal bovine serum and 1% penicillin/streptomycin, intervening when the cells grew to 60-70%. The rapid pacing HL-1 cell model was prepared as we previously described [13] . In brief, the HL-1 cells were paced by electric eld stimulation (600 times/min), intensity 1.5 V/cm, continuous stimulation for 48 h.…”

“…The rapid atrial pacing canine model was prepared as we previously described [13] . Brie y, eighteen beagles were randomly divided into Sham group (n=6), Pacing group (n=6), and Pacing+TRAM-34 group (n=6).…”

“…Procedural stimulation was performed after placing multi-lead electrodes in various parts of the atrium. In brief, we measured the atrial effective refractory period (ERP), and the inducibility and duration of AF [13] .…”

The role of microRNAs in ferroptosis

“…As a part of the Xc − transporter, SLC7A11 also plays a significant role in the antioxidant system ( Jyotsana et al, 2022 ). The study of Liu et al inhibited cardiac fibroblast-derived exon-miR-23a-3p by using the exosome inhibitor GW4869, and inhibition of miR-23a-3p resulted in upregulation of SLC7A11, thereby reducing ferroptosis in H9c2 cardiomyocytes and preventing continued development of atrial flutter ( Liu D. et al, 2022 ). It suggests that miR-23a-3p inhibition increases intracellular cystine and GSH levels, thereby neutralizing ROS and treating atrial fibrillation.…”