Progress in molecular biology and translational science: Epigenetics in cardiovascular health and disease

Acetylation-Mediated Post-Translational Modification of Pyruvate Dehydrogenase Plays a Critical Role in the Regulation of the Cellular Acetylome During Metabolic Stress

Background: Cardiac diseases remain one of the leading causes of death globally, often linked to ischemic conditions that can affect cellular homeostasis and metabolism, which can lead to the development of cardiovascular dysfunction. Considering the effect of ischemic cardiomyopathy on the global population, it is vital to understand the impact of ischemia on cardiac cells and how ischemic conditions change different cellular functions through post-translational modification of cellular proteins. Methods: To understand the cellular function and fine-tuning during stress, we established an ischemia model using neonatal rat ventricular cardiomyocytes. Further, the level of cellular acetylation was determined by Western blotting and affinity chromatography coupled with liquid chromatography-mass spectroscopy. Results: Our study found that the level of cellular acetylation significantly reduced during ischemic conditions compared to normoxic conditions. Further, in mass spectroscopy data, 179 acetylation sites were identified in the proteins in ischemic cardiomyocytes. Among them, acetylation at 121 proteins was downregulated, and 26 proteins were upregulated compared to the control groups. Differentially, acetylated proteins are mainly involved in cellular metabolism, sarcomere structure, and motor activity. Additionally, a protein enrichment study identified that the ischemic condition impacted two major biological pathways: the acetyl-CoA biosynthesis process from pyruvate and the tricarboxylic acid cycle by deacetylation of the associated proteins. Moreover, most differential acetylation was found in the protein pyruvate dehydrogenase complex. Conclusions: Understanding the differential acetylation of cellular protein during ischemia may help to protect against the harmful effect of ischemia on cellular metabolism and cytoskeleton organization. Additionally, our study can help to understand the fine-tuning of proteins at different sites during ischemia.

The Transcription Factor Tbx5-Dependent Epigenetic Modification Contributes to Neuropathic Allodynia by Activating TRPV1 Expression in the Dorsal Horn

Nerve injury can induce aberrant changes in the spine; these changes are due to, or at least partly governed by, transcription factors that contribute to the genesis of neuropathic allodynia. Here, we showed that spinal nerve ligation (SNL, a clinical neuropathic allodynia model) increased the expression of the transcription factor Tbx5 in the injured dorsal horn in male Sprague Dawley rats. In contrast, blocking this upregulation alleviated SNL-induced mechanical allodynia, and there was no apparent effect on locomotor function. Moreover, SNL-induced Tbx5 upregulation promoted the recruitment and interaction of GATA4 and Brd4 by enhancing its binding activity to H3K9Ac, which was enriched at the Trpv1 promotor, leading to an increase in TRPV1 transcription and the development of neuropathic allodynia. In addition, nerve injury-induced expression of Fbxo3, which abates Fbxl2-dependent Tbx5 ubiquitination, promoted the subsequent Tbx5-dependent epigenetic modification of TRPV1 expression during SNL-induced neuropathic allodynia. Collectively, our findings indicated that spinal Tbx5-dependent TRPV1 transcription signaling contributes to the development of neuropathic allodynia via Fbxo3-dependent Fbxl2 ubiquitination and degradation. Thus, we propose a potential medical treatment strategy for neuropathic allodynia by targeting Tbx5.

Type 2 diabetes mellitus and cardiometabolic outcomes in metabolic dysfunction-associated steatotic liver disease population

The metabolic syndrome, characterized by type 2 diabetes mellitus (T2DM), hypertension, hyperlipidemia, and obesity, collectively increases the risk of cardiovascular diseases. Nonalcoholic fatty liver disease (NAFLD) is a prominent manifestation, affecting over a third of the global population with a concerning annual increase in prevalence. Nearly 70 % of overweight individuals have NAFLD, and NAFLD-related deaths are predicted to rise, especially among young adults. The association of T2DM and NAFLD has led to the proposal of "metabolic dysfunction-associated steatotic liver disease" (MASLD) terminology, encompassing individuals with T2DM, overweight/obesity, hypertension, hypertriglyceridemia, or low HDL-cholesterol. Patients with MASLD will likely have double the risk of developing T2DM, and the combination of insulin resistance, overweight/obesity, and MASLD significantly elevates the risk of T2DM. Cardiovascular diseases remain the leading cause of mortality in the MASLD and T2DM population, with MASLD directly associated with coronary artery disease, compounded by coexisting insulin resistance and T2DM. Urgency lies in early detection of subclinical cardiovascular diseases among patients with T2DM and MASLD. Novel strategies targeting multiple pathways offer hope for effectively improving cardiometabolic health. Understanding and addressing the intertwined factors contributing to these disorders can pave the way towards better management and prevention of cardiometabolic complications.

Arterial Stiffness: From Basic Primers to Integrative Physiology

The elastic properties of conductance arteries are one of the most important hemodynamic functions in the body, and data continue to emerge regarding the importance of their dysfunction in vascular aging and a range of cardiovascular diseases. Here, we provide new insight into the integrative physiology of arterial stiffening and its clinical consequence. We also comprehensively review progress made on pathways/molecules that appear today as important basic determinants of arterial stiffness, particularly those mediating the vascular smooth muscle cell (VSMC) contractility, plasticity and stiffness. We focus on membrane and nuclear mechanotransduction, clearance function of the vascular wall, phenotypic switching of VSMCs, immunoinflammatory stimuli and epigenetic mechanisms. Finally, we discuss the most important advances of the latest clinical studies that revisit the classical therapeutic concepts of arterial stiffness and lead to a patient-by-patient strategy according to cardiovascular risk exposure and underlying disease.

miRNAs Epigenetic Tuning of Wall Remodeling in the Early Phase after Myocardial Infarction: A Novel Epidrug Approach

Myocardial infarction (MI) is one of the leading causes of death in Western countries. An early diagnosis decreases subsequent severe complications such as wall remodeling or heart failure and improves treatments and interventions. Novel therapeutic targets have been recognized and, together with the development of direct and indirect epidrugs, the role of non-coding RNAs (ncRNAs) yields great expectancy. ncRNAs are a group of RNAs not translated into a product and, among them, microRNAs (miRNAs) are the most investigated subgroup since they are involved in several pathological processes related to MI and post-MI phases such as inflammation, apoptosis, angiogenesis, and fibrosis. These processes and pathways are finely tuned by miRNAs via complex mechanisms. We are at the beginning of the investigation and the main paths are still underexplored. In this review, we provide a comprehensive discussion of the recent findings on epigenetic changes involved in the first phases after MI as well as on the role of the several miRNAs. We focused on miRNAs function and on their relationship with key molecules and cells involved in healing processes after an ischemic accident, while also giving insight into the discrepancy between males and females in the prognosis of cardiovascular diseases.