RESUMO
Physical exercise has been widely acknowledged as a beneficial lifestyle alteration and a potent non-pharmacological treatment for heart disease. Extensive investigations have revealed the beneficial effects of exercise on the heart and the underlying mechanisms involved. Exercise is considered one of the key factors that can lead to epigenetic alterations. The increasing number of identified molecules in the exercised heart has led to many studies in recent years that have explored the cellular function of ncRNAs and RNA modifications in the heart. Investigating the regulatory role of RNA-mediated epigenetic regulation in exercised hearts will contribute to the development of therapeutic strategies for the management of heart diseases. This review aims to summarize the positive impact of exercise on cardiac health. We will first provide an overview of the mechanisms through which exercise offers protection to the heart. Subsequently, we will delve into the current understanding of ncRNAs, specifically miRNAs, lncRNAs, and circRNAs, as well as RNA modification, focusing on RNA m6A and RNA A-to-I editing, and how they contribute to exercise-induced benefits for the heart. Lastly, we will explore the emerging therapeutic strategies that utilize exercise-mediated RNA epigenetic regulation in the treatment of heart diseases, while also addressing the challenges faced in this field.
Assuntos
Epigênese Genética , Exercício Físico , Humanos , Animais , MicroRNAs/genética , MicroRNAs/metabolismo , RNA não Traduzido/genética , RNA não Traduzido/metabolismo , RNA Circular/genética , RNA Circular/metabolismo , Cardiopatias/genética , Cardiopatias/terapia , Cardiopatias/metabolismo , RNA/genética , RNA/metabolismo , Miocárdio/metabolismoRESUMO
The myocardial Na(+)/H(+) exchanger-1 (NHE1) plays a major role in regulation of intracellular pH, and its upregulation has been implicated in increased ischemia-reperfusion injury and other pathologies. Hydrogen peroxide (H2O2) increases NHE1 activity acutely via ERK1/2 signaling. Chronic strenuous exercise upregulates NHE1 in skeletal muscle, but we hypothesize this will not occur in the heart, because exercise creates a cardioprotective phenotype. NHE1 activity and its regulation by H2O2 were examined at physiological pH using isolated cardiomyocytes from female Sprague-Dawley rats exercised on a treadmill for 5 wk (E; n = 11). Compared with sedentary (S; n = 15), E displayed increases (P < 0.05) in heart-to-body weight ratio (6.8%) and plantaris mitochondria content (89%). NHE1 activity (acid efflux rate following an acid load) was 209% greater in E (0.65 ± 0.12 vs. 2.01 ± 0.29 fmol/min). The difference was attributed primarily to greater cell volume (22.2 ± 0.6 vs. 34.3 ± 1.1 pl) and intracellular pH-buffering capacity (33.94 ± 1.59 vs. 65.82 ± 5.20 mM/pH unit) of E myocytes. H2O2 stimulation (100 µM) raised NHE1 activity significantly less in E (45%) than S (167%); however, activity remained 185% greater in E. ERK1/2 inhibition abrogated the increases. H2O2-stimulated ERK1/2 phosphorylation levels normalized to total ERK1/2 were similar between groups. Content of NHE1 and activities of H2O2 scavengers were also similar. We observed that intracellular pH-buffering capacity differences between groups became progressively less with declining pH, which may be an exercise-induced cardioprotective adaptation to lower NHE1 activity during certain pathological situations. We conclude that strenuous endurance exercise increases myocardial NHE1 activity at physiological pH, which would likely enhance cardiac performance under physiological conditions.