Down-regulation of OIP5-AS1 inhibits obesity-induced myocardial pyroptosis and miR-22/NLRP3 inflammasome axis

Synergistic Effects of Weight Loss and Catheter Ablation: Can microRNAs Serve as Predictive Biomarkers for the Prevention of Atrial Fibrillation Recurrence?

In atrial fibrillation (AF), multifactorial pathologic atrial alterations are manifested by structural and electrophysiological changes known as atrial remodeling. AF frequently develops in the context of underlying cardiac abnormalities. A critical mechanistic role played by atrial stretch is played by abnormal substrates in a number of conditions that predispose to AF, including obesity, heart failure, hypertension, and sleep apnea. The significant role of overweight and obesity in the development of AF is known; however, the differential effect of overweight, obesity, cardiovascular comorbidities, lifestyle, and other modifiable risk factors on the occurrence and recurrence of AF remains to be determined. Reverse remodeling of the atrial substrate and subsequent reduction in the AF burden by conversion into a typical sinus rhythm has been associated with weight loss through lifestyle changes or surgery. This makes it an essential pillar in the management of AF in obese patients. According to recently published research, microRNAs (miRs) may function as post-transcriptional regulators of genes involved in atrial remodeling, potentially contributing to the pathophysiology of AF. The focus of this review is on their modulation by both weight loss and catheter ablation interventions to counteract atrial remodeling in AF. Our analysis outlines the experimental and clinical evidence supporting the synergistic effects of weight loss and catheter ablation (CA) in reversing atrial electrical and structural remodeling in AF onset and in recurrent post-ablation AF by attenuating pro-thrombotic, pro-inflammatory, pro-fibrotic, arrhythmogenic, and male-sex-associated hypertrophic remodeling pathways. Furthermore, we discuss the promising role of miRs with prognostic potential as predictive biomarkers in guiding approaches to AF recurrence prevention.

Circ_005077 accelerates myocardial lipotoxicity induced by high-fat diet via CyPA/p47PHOX mediated ferroptosis

The long-term high-fat diet (HFD) can cause myocardial lipotoxicity, which is characterized pathologically by myocardial hypertrophy, fibrosis, and remodeling and clinically by cardiac dysfunction and heart failure in patients with obesity and diabetes. Circular RNAs (circRNAs), a novel class of noncoding RNA characterized by a ring formation through covalent bonds, play a critical role in various cardiovascular diseases. However, few studies have been conducted to investigate the role and mechanism of circRNA in myocardial lipotoxicity. Here, we found that circ_005077, formed by exon 2-4 of Crmp1, was significantly upregulated in the myocardium of an HFD-fed rat. Furthermore, we identified circ_005077 as a novel ferroptosis-related regulator that plays a role in palmitic acid (PA) and HFD-induced myocardial lipotoxicity in vitro and in vivo. Mechanically, circ_005077 interacted with Cyclophilin A (CyPA) and inhibited its degradation via the ubiquitination proteasome system (UBS), thus promoting the interaction between CyPA and p47phox to enhance the activity of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase responsible for ROS generation, subsequently inducing ferroptosis. Therefore, our results provide new insights into the mechanisms of myocardial lipotoxicity, potentially leading to the identification of a novel therapeutic target for the treatment of myocardial lipotoxicity in the future.

Aerobic exercise mitigates high-fat diet-induced cardiac dysfunction, pyroptosis, and inflammation by inhibiting STING-NLRP3 signaling pathway

Obesity has been identified as an independent risk factor for cardiovascular disease. Recent reports have highlighted the significance of stimulator of interferon genes (STING)-NOD-like receptor protein 3 (NLRP3) signaling pathway mediated pyroptosis, and inflammation in cardiovascular disease. Previous studies have demonstrated that exercise training effectively prevents cardiac pyroptosis and inflammation in high-fat diet (HFD)-fed mice. However, it is currently unknown whether exercise reduces pyroptosis and inflammation in obese hearts by targeting the STING-NLRP3 signaling pathway. We investigated the impact of an 8-week aerobic exercise regimen on cardiac function, pyroptosis, inflammation, and the STING-NLRP3 signaling pathway in HFD-induced obese mice. Additionally, to explore the underlying mechanism of STING in exercise-mediated cardioprotection, we administered intraperitoneal injections of the STING agonist diABZI to the mice. Furthermore, to investigate the role of the STING-NLRP3 signaling pathway in HFD-induced cardiac dysfunction, we administered adeno-associated virus 9 (AAV9) encoding shRNA targeting STING (shRNA-STING) via tail vein injection to knockdown STING expression specifically in mouse hearts. After one week of AAV9 injection, we intraperitoneally injected nigericin as an NLRP3 agonist. We first found that aerobic exercise effectively suppressed HFD-mediated upregulation of STING and NLRP3 in the hearts. Moreover, we demonstrated that the protective effect of aerobic exercise in HFD-induced cardiac dysfunction, pyroptosis, and inflammation was impaired by stimulating the STING pathway using diABZI. Additionally, activation of the NLRP3 with nigericin abolished the ameliorative effect of STING deficiency in HFD-induced cardiac dysfunction, pyroptosis, and inflammation. Based on these findings, we concluded that 8-week aerobic exercise alleviates HFD-induced cardiac dysfunction, pyroptosis, and inflammation by targeting STING-NLRP3 signaling pathway. Inhibition of STING-NLRP3 signaling pathway may serve as a promising therapeutic strategy against obesity-induced cardiomyopathy.