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Atrial fibrillation (AF) and ischemic heart disease (IHD) represent the two most common clinical cardiac diseases, characterized by angina, arrhythmia, myocardial damage, and cardiac dysfunction, significantly contributing to cardiovascular morbidity and mortality and posing a heavy socio-economic burden on society worldwide. Current treatments of these two diseases are mainly symptomatic and lack efficacy. There is thus an urgent need to develop novel therapies based on the underlying pathophysiological mechanisms. Emerging evidence indicates that oxidative DNA damage might be a major underlying mechanism that promotes a variety of cardiac diseases, including AF and IHD. Antioxidants, nicotinamide adenine dinucleotide (NAD+) boosters, and enzymes involved in oxidative DNA repair processes have been shown to attenuate oxidative damage to DNA, making them potential therapeutic targets for AF and IHD. In this review, we first summarize the main molecular mechanisms responsible for oxidative DNA damage and repair both in nuclei and mitochondria, then describe the effects of oxidative DNA damage on the development of AF and IHD, and finally discuss potential targets for oxidative DNA repair-based therapeutic approaches for these two cardiac diseases. [ABSTRACT FROM AUTHOR]

Cardiac disease is still the leading cause of morbidity and mortality worldwide, despite some exciting and innovative improvements in clinical management. In particular, atrial fibrillation (AF) and heart failure show a steep increase in incidence and healthcare costs due to the ageing population. Although research revealed novel insights in pathways driving cardiac disease, the exact underlying mechanisms have not been uncovered so far. Emerging evidence indicates that derailed proteostasis (i.e., the homeostasis of protein expression, function and clearance) is a central component driving cardiac disease. Within proteostasis derailment, key roles for endoplasmic reticulum (ER) and mitochondrial stress have been uncovered. Here, we describe the concept of ER and mitochondrial stress and the role of interactions between the ER and mitochondria, discuss how imbalance in the interactions fuels cardiac ageing and cardiac disease (including AF), and finally assess the potential of drugs directed at conserving the interaction as an innovative therapeutic target to improve cardiac function. [ABSTRACT FROM AUTHOR]

Due to ageing of the population, the incidence of cardiovascular diseases will increase in the coming years, constituting a substantial burden on health care systems. In particular, atrial fibrillation (AF) is approaching epidemic proportions. It has been identified that the derailment of proteostasis, which is characterized by the loss of homeostasis in protein biosynthesis, folding, trafficking, and clearance by protein degradation systems such as autophagy, underlies the development of common cardiac diseases. Among various safeguards within the proteostasis system, autophagy is a vital cellular process that modulates clearance of misfolded and proteotoxic proteins from cardiomyocytes. On the other hand, excessive autophagy may result in derailment of proteostasis and therefore cardiac dysfunction. Here, we review the interplay between autophagy and proteostasis in the healthy heart, discuss the imbalance between autophagy and proteostasis during cardiac diseases, including AF, and finally explore new druggable targets which may limit cardiac disease initiation and progression. [ABSTRACT FROM AUTHOR]

Perpetuation of atrial fibrillation (AF) is caused by electropathology, which is defined as impairment of electrical activation caused by structural and metabolic remodeling of cardiomyocytes. We previously dissected the molecular mechanisms underlying electropathology and identified an important role for histone deacetylases (HDACs). HDACs catalyze the removal of acetyl-groups from lysine residues within nucleosomal histone tails and many non-histone proteins. Various HDAC inhibitors are efficacious in attenuating electropathology, and improve contractile function in experimental AF. Emerging evidence reveals novel mechanisms by which HDAC inhibitors prevent cardiac electropathology and thereby benefit the heart during AF. These mechanisms include post-translational modification of contractile and structural proteins and changes in gene expression. In this review paper, we summarize recent findings on novel functions of zinc-dependent HDACs in electropathology and discuss the potential for pharmacological HDAC inhibition as a strategy to treat AF. • Perpetuation of atrial fibrillation (AF) is caused by electropathology. • HDAC inhibitors attenuate electropathology in AF and other cardiac diseases. • HDACs deacetylate contractile and structural proteins in the heart. • HDACs regulate gene expression by targeting transcription factors in the heart. • HDAC3 and HDAC6 represent novel therapeutic targets for AF. [ABSTRACT FROM AUTHOR]