Molecular signaling of G-protein-coupled receptor in chronic heart failure and associated complications

Longevity mechanisms in cardiac aging: exploring calcium dysregulation and senescence

Cardiac aging is a multistep process that results in a loss of various structural and functional heart abilities, increasing the risk of heart disease. Since its remarkable discovery in the early 1800s, when limestone is heated, calcium's importance has been defined in numerous ways. It can help stiffen shells and bones, function as a reducing agent in chemical reactions, and play a central role in cellular signalling. The movement of calcium ions in and out of cells and between those is referred to as calcium signalling. It influences the binding of the ligand, enzyme activity, electrochemical gradients, and other cellular processes. Calcium signalling is critical for both contraction and relaxation under the sliding filament model of heart muscle. However, with age, the heart undergoes changes that lead to increases in cardiac dysfunction, such as myocardial fibrosis, decreased cardiomyocyte function, and noxious disturbances in calcium homeostasis. Additionally, when cardiac tissues age, cellular senescence, a state of irreversible cell cycle arrest, accumulates and begins to exacerbate tissue inflammation and fibrosis. This review explores the most recent discoveries regarding the role of senescent cell accumulation and calcium signalling perturbances in cardiac aging. Additionally, new treatment strategies are used to reduce aged-related heart dysfunction by targeting senescent cells and modulating calcium homeostasis.

The interplay of senescence and MMPs in myocardial infarction: implications for cardiac aging and therapeutics

Aging is associated with a marked increase in cardiovascular diseases, such as myocardial infarction (MI). Cellular senescence is also a crucial factor in the development of age-related MI. Matrix metalloproteinases (MMPs) interaction with cellular senescence is a critical determinant of MI development and outcomes, most notably in the aged heart. After experiencing a heart attack, senescent cells exhibit a Senescence-Associated Secretory Phenotype (SASP) and are involved in tissue regeneration and chronic inflammation. MMPs are necessary for extracellular matrix proteolysis and have a biphasic effect, promoting early heart healing and detrimental change if overexpressed shortly. This review analyses the complex connection between senescence and MMPs in MI and how it influences elderly cardiac performance. Critical findings suggest that increasing cellular senescence in aged hearts elevates MMP activity and aggravates extended ventricular remodeling and dysfunction. Additionally, we explore potential therapeutics that address MMPs and senescence to enhance old MI patient myocardial performance and regeneration.

ANRIL's Epigenetic Regulation and Its Implications for Cardiovascular Disorders

Cardiovascular disorders (CVDs) are a major global health concern, but their underlying molecular mechanisms are not fully understood. Recent research highlights the role of long noncoding RNAs (lncRNAs), particularly ANRIL, in cardiovascular development and disease. ANRIL, located in the human genome's 9p21 region, significantly regulates cardiovascular pathogenesis. It controls nearby tumor suppressor genes CDKN2A/B through epigenetic pathways, influencing cell growth and senescence. ANRIL interacts with epigenetic modifiers, leading to altered histone modifications and gene expression changes. It also acts as a transcriptional regulator, impacting key genes in CVD development. ANRIL's involvement in cardiovascular epigenetic regulation suggests potential therapeutic strategies. Manipulating ANRIL and its associated epigenetic modifiers could offer new approaches to managing CVDs and preventing their progression. Dysregulation of ANRIL has been linked to various cardiovascular conditions, including coronary artery disease, atherosclerosis, ischemic stroke, and myocardial infarction. This abstract provides insights from recent research, emphasizing ANRIL's significance in the epigenetic landscape of cardiovascular disorders. By shedding light on ANRIL's role in cellular processes and disease development, the abstract highlights its potential as a therapeutic target for addressing CVDs.

Noncoding RNAs as therapeutic targets in autophagy-related diabetic cardiomyopathy

Diabetic cardiomyopathy, a multifaceted complication of diabetes mellitus, remains a major challenge in clinical management due to its intricate pathophysiology. Emerging evidence underscores the pivotal role of autophagy dysregulation in the progression of diabetic cardiomyopathy, providing a novel avenue for therapeutic intervention. Noncoding RNAs (ncRNAs), a diverse class of regulatory molecules, have recently emerged as promising candidates for targeted therapeutic strategies. The exploration of various classes of ncRNAs, including microRNAs (miRNAs), long noncoding RNAs (lncRNAs), and circular RNAs (circRNAs) reveal their intricate regulatory networks in modulating autophagy and influencing the pathophysiological processes associated with diabetic cardiomyopathy. The nuanced understanding of the molecular mechanisms underlying ncRNA-mediated autophagic regulation offers a rationale for the development of precise and effective therapeutic interventions. Harnessing the regulatory potential of ncRNAs presents a promising frontier for the development of targeted and personalized therapeutic strategies, aiming to ameliorate the burden of diabetic cardiomyopathy in affected individuals. As research in this field advances, the identification and validation of specific ncRNA targets hold immense potential for the translation of these findings into clinically viable interventions, ultimately improving outcomes for patients with diabetic cardiomyopathy. This review encapsulates the current understanding of the intricate interplay between autophagy and diabetic cardiomyopathy, with a focus on the potential of ncRNAs as therapeutic targets.

Pyroptosis-related non-coding RNAs emerging players in atherosclerosis pathology

Globally, atherosclerosis a persistent inflammatory condition of the artery walls continues to be the primary cause of cardiovascular illness and death. The ncRNAs are important regulators of important signalling pathways that affect pyroptosis and the inflammatory environment in atherosclerotic plaques. Comprehending the complex interaction between pyroptosis and non-coding RNAs (ncRNAs) offers fresh perspectives on putative therapeutic targets for ameliorating cardiovascular problems linked to atherosclerosis. The discovery of particular non-coding RNA signatures linked to the advancement of atherosclerosis could lead to the creation of novel biomarkers for risk assessment and customised treatment approaches. A thorough investigation of the regulatory networks regulated by these non-coding RNAs has been made possible by the combination of cutting-edge molecular methods and bioinformatics tools. Studying pyroptosis-related ncRNAs in detail appears to be a promising way to advance our understanding of disease pathophysiology and develop focused therapeutic methods as we work to unravel the complex molecular tapestry of atherosclerosis. This review explores the emerging significance of non-coding RNAs (ncRNAs) in the regulation of pyroptosis and their consequential impact on atherosclerosis pathology.

Unraveling the role of Xist RNA in cardiovascular pathogenesis

Understanding the molecular pathways behind cardiovascular illnesses is crucial due to the enormous worldwide health burden they impose. New insights into the role played by Xist (X-inactive specific transcript) RNA in the onset and progression of cardiovascular diseases have emerged from recent studies. Since its discovery, Xist RNA has been known for its role in X chromosome inactivation during embryogenesis; however, new data suggest that its function extends well beyond the control of sex chromosomes. The regulatory roles of Xist RNA are extensive, encompassing epigenetic changes, gene expression, cellular identity, and sex chromosomal inactivation. There is potential for the involvement of this complex regulatory web in a wide range of illnesses, including cardiovascular problems. Atherosclerosis, hypertrophy, and cardiac fibrosis are all conditions linked to dysregulation of Xist RNA expression. Alterations in DNA methylation and histones are two examples of epigenetic changes that Xist RNA orchestrates, leading to modifications in gene expression patterns in different cardiovascular cells. Additionally, Xist RNA has been shown to contribute to the development of cardiovascular illnesses by modulating endothelial dysfunction, inflammation, and oxidative stress responses. New treatment approaches may become feasible with a thorough understanding of the complex function of Xist RNA in cardiovascular diseases. By focusing on Xist RNA and the regulatory network with which it interacts, we may be able to slow the progression of atherosclerosis, cardiac hypertrophy, and fibrosis, thereby opening novel therapeutic options for cardiovascular diseases amenable to precision medicine. This review summarizes the current state of knowledge concerning the impact of Xist RNA in cardiovascular disorders.

An overview of receptor endocytosis and signaling

Endocytosis is a cellular process which mediates receptor internalization, nutrient uptake, and the regulation of cell signaling. Microorganisms (many bacteria and viruses) and toxins also use the same process and enter the cells. Generally, endocytosis is considered in the three forms such as phagocytosis (cell eating), pinocytosis (cell drinking), and highly selective receptor-mediated endocytosis (clathrin-dependent and independent). Several endocytic routes exist in an analogous, achieving diverse functions. Most studies on endocytosis have used transformed cells in culture. To visualize the receptor internalization, trafficking, and signaling in subcellular organelles, a green fluorescent protein-tagged receptor has been utilized. It also helps to visualize the endocytosis effects in live-cell imaging. Confocal laser microscopy increases our understanding of receptor endocytosis and signaling. Site-directed mutagenesis studies demonstrated that many short-sequence motifs of the cytoplasmic domain of receptors significantly play a vital role in receptor internalization, subcellular trafficking, and signaling. However, other factors also regulate receptor internalization through clathrin-coated vesicles. Receptor endocytosis can occur through clathrin-dependent and clathrin-independent pathways. This chapter briefly discusses the internalization, trafficking, and signaling of various receptors in normal conditions. In addition, it also highlights the malfunction of the receptor in disease conditions.

Receptor biology: Challenges and opportunities

Receptor biology provides a great opportunity to understand the ligand-receptor signaling involved in health and disease processes. Receptor endocytosis and signaling play a vital role in health conditions. Receptor-based signaling is the main form of communication between cells and cells with the environment. However, if any irregularities happen during these events, the consequences of pathophysiological conditions occur. Various methods are utilized to know structure, function, and regulation of receptor proteins. Further, live-cell imaging and genetic manipulations have aided in the understanding of receptor internalization, subcellular trafficking, signaling, metabolic degradation, etc. Understanding the genetics, biochemistry, and physiology of receptors and ligands is very helpful to explore various aspects such as prognosis, diagnosis, and treatment of disease. However, there are enormous challenges that exist to explore receptor biology further. This chapter briefly discusses the current challenges and emerging opportunities of receptor biology.

Effects of enteral nutrition on heart function, inflammatory markers and immune function in elderly patients with chronic heart failure

Objectives:

To evaluate the effect of enteral nutrition on heart function, inflammatory markers and immune function in elderly patients with chronic heart failure and its clinical significance.

Methods:

Eighty patients with moderate and severe heart failure admitted to the Cardiology Intensive Care Unit (CCU) of Baoding First Central Hospital from May 2019 to May 2020 were included in this study and randomly divided into two groups: the experimental group and the control group, with 40 patients in each group. The experimental group was given enteral nutrition support therapy on the basis of conventional therapy for one month, while the control group was given restricted salt and water intake on the basis of conventional therapy, and patients were given free diet according to their wishes. The changes in heart function before and after treatment, changes in inflammatory factors such as TNF-a, CRP, IL-6, changes in levels of immunoglobulins such as IgA, IgM, and IgG, and the improvement of the performance status of the two groups were compared and analyzed.

Results:

After treatment, indicators such as BNP, LVEDD, LVEF and 6min walking distance in the experimental group were significantly improved compared with the control group, with statistically significant differences (p<0.05), and the levels of inflammatory factors such as TNF-a, CRP and IL-6 in the experimental group were significantly reduced compared with those in the control group (p=0.00). The levels of IgG, IgA, IgM and other immunoglobulins in the experimental group improved more significantly after treatment than those in the control group, with statistically significant differences (IgG, IgA, p=0.00; IgM, p=0.01). Moreover, the experimental group was significantly superior to the control group in the improvement rate of performance status score (ECOG) after treatment (p=0.04); The incidence of gastrointestinal adverse reactions in the experimental group was 20%, and that in the control group was 15%. No statistically significant difference can be observed in the gastrointestinal tolerance of both groups (p=0.56).

Conclusions:

Reasonable enteral nutrition boasts a variety of benefits for the recovery of elderly patients with chronic heart failure. With reasonable enteral nutrition, the heart function of elderly patients with chronic heart failure can be significantly improved, inflammatory factors can be reduced, immunity and performance status can be enhanced, and gastrointestinal tolerance can be ameliorated without obvious gastrointestinal reactions.

Cardiovascular angiotensin II type 1 receptor biased signaling: Focus on non-Gq-, non-βarrestin-dependent signaling

The physiological and pathophysiological roles of the angiotensin II type 1 (AT1) receptor, a G protein-coupled receptor ubiquitously expressed throughout the cardiovascular system, have been the focus of intense investigations for decades. The success of angiotensin converting enzyme inhibitors (ACEIs) and of angiotensin receptor blockers (ARBs), which are AT1R-selective antagonists/inverse agonists, in the treatment of heart disease is a testament to the importance of this receptor for cardiovascular homeostasis. Given the pleiotropic signaling of the cardiovascular AT1R and, in an effort to develop yet better drugs for heart disease, the concept of biased signaling has been exploited to design and develop biased AT1R ligands that selectively activate β-arrestin transduction pathways over Gq protein-dependent pathways. However, by focusing solely on Gq or β-arrestins, studies on AT1R "biased" signaling & agonism tend to largely ignore other non-Gq-, non β-arrestin-dependent signaling modalities the very versatile AT1R employs in cardiovascular tissues, including two very important types of signal transducers/regulators: other G protein types (e.g., Gi/o, G12/13) & the Regulator of G protein Signaling (RGS) proteins. In this review, we provide a brief overview of the current state of cardiovascular AT1R biased signaling field with a special focus on the non-Gq-, non β-arrestin-dependent signaling avenues of this receptor in the cardiovascular system, which usually get left out of the conversation of "biased" AT1R signal transduction.

Adrenal angiotensin II type 1 receptor biased signaling: The case for "biased" inverse agonism for effective aldosterone suppression

Angiotensin II (AngII) uses two distinct G protein-coupled receptor (GPCR) types, AT1R and AT2R, to exert a plethora of physiologic effects in the body and to significantly affect cardiovascular homeostasis. Although not much is known about the signaling of the AT2R, AT1R signaling is known to be quite pleiotropic, mobilizing a variety of signal transducers inside cells to produce a biological outcome. When the outcome in question is aldosterone production from the adrenal cortex, the main transducers activated specifically by the adrenocortical AT1R to signal toward that cellular effect are the Gq/11 protein alpha subunits and the β-arrestins (also known as Arrestin-2 and -3). The existence of various downstream pathways the AT1R signal can travel down on has led to the ever-expanding filed of GPCR pharmacology termed "biased" signaling, which refers to a ligand preferentially activating one signaling pathway over others downstream of the same receptor in the same cell. However, "biased" signaling or "biased" agonism is therapeutically desirable only when the downstream pathways lead to different or opposite cellular outcomes, so the pathway promoting the beneficial effect can be selectively activated over the pathway that leads to detrimental consequences. In the case of the adrenal AT1R, both Gq/11 proteins and β-arrestins mediate signaling to the same end-result: aldosterone synthesis and secretion. Therefore, both pathways need to remain inactive in the adrenal cortex to fully suppress the production of aldosterone, which is one of the culprit hormones elevated in chronic heart failure, hypertension, and various other cardiovascular diseases. Variations in the effectiveness of the AT1R antagonists, which constitute the angiotensin receptor blocker (ARB) class of drugs (also known as sartans), at the relative blockade of these two pathways downstream of the adrenal AT1R opens the door to the flip term "biased" inverse agonism at the AT1R. ARBs that are unbiased and equipotent inverse agonists for both G proteins and β-arrestins at this receptor, like candesartan and valsartan, are the most preferred agents with the best efficacy at reducing circulating aldosterone, thereby ameliorating heart failure. In the present review, the biased signaling of the adrenal AT1R, particularly in relation to aldosterone production, is examined and the term "biased" inverse agonism at the AT1R is introduced and explained, as a means of pharmacological categorization of the various agents within the ARB drug class.

Risk Prediction in Patients With Heart Failure With Preserved Ejection Fraction Using Gene Expression Data and Machine Learning

Heart failure with preserved ejection fraction (HFpEF) has become a major health issue because of its high mortality, high heterogeneity, and poor prognosis. Using genomic data to classify patients into different risk groups is a promising method to facilitate the identification of high-risk groups for further precision treatment. Here, we applied six machine learning models, namely kernel partial least squares with the genetic algorithm (GA-KPLS), the least absolute shrinkage and selection operator (LASSO), random forest, ridge regression, support vector machine, and the conventional logistic regression model, to predict HFpEF risk and to identify subgroups at high risk of death based on gene expression data. The model performance was evaluated using various criteria. Our analysis was focused on 149 HFpEF patients from the Framingham Heart Study cohort who were classified into good-outcome and poor-outcome groups based on their 3-year survival outcome. The results showed that the GA-KPLS model exhibited the best performance in predicting patient risk. We further identified 116 differentially expressed genes (DEGs) between the two groups, thus providing novel therapeutic targets for HFpEF. Additionally, the DEGs were enriched in Gene Ontology terms and Kyoto Encyclopedia of Genes and Genomes pathways related to HFpEF. The GA-KPLS-based HFpEF model is a powerful method for risk stratification of 3-year mortality in HFpEF patients.