Redox-signalling and Redox Biomarkers in Cardiovascular Health and Disease.

Overproduction of reactive nitrogen and oxygen species (RNS and ROS) has been linked to the pathogenesis of diabetes, hypertension, hyperlipidemia, stroke, angina, and other cardiovascular diseases. These species are produced in part by the mitochondrial respiratory chain, NADPH oxidase, and xanthine oxidase. RNS and ROS both contribute to oxidative stress, which is necessary for the development of cardiovascular disorders. In addition to ROS species like hydroxyl ion, hydrogen peroxide, and superoxide anion, RNS species like nitric oxide, peroxynitrous acid, peroxynitrite, and nitrogen dioxide radicals have also been linked to a number of cardiovascular conditions. They promote endothelial dysfunction, vascular inflammation, lipid peroxidation, and oxidative damage, all of which contribute to the development of cardiovascular pathologies. It's crucial to understand the mechanisms that result in the production of RNS and ROS in order to identify potential therapeutic targets. Redox biomarkers serve as indicators of oxidative stress, making them crucial tools for diagnosing and predicting cardiovascular states. The advancements in proteomics, metabolomics, genomics, and transcriptomics have made the identification and detection of these small molecules possible. The following redox biomarkers are notable examples: 3-nitrotyrosine, 4-hydroxy-2-nonenal, 8- iso-prostaglandin F2, 8-hydroxy-2-deoxyguanosine, malondialdehyde, Diacron reactive oxygen metabolites, total thiol, and specific microRNAs (e.g. miRNA199, miRNA21, miRNA1254, miRNA1306-5p, miRNA26b-5p, and miRNA660-5p) are examples. Although redox biomarkers have great potential, their clinical applicability faces challenges. Redox biomarkers frequently have a short half-life and exist in small quantities in the blood, making them challenging to identify and measure. The interpretation of biomarker data may also be influenced by confounding factors and the complex interplay of various oxidative stress pathways. Therefore, in-depth validation studies and the development of sensitive and precise detection methods are needed to address these problems. In the search for redox biomarkers, cutting-edge techniques like mass spectrometry, immunoassays, and molecular diagnostics are applied. New platforms and technologies have made it possible to accurately detect and monitor redox biomarkers, which facilitates their use in clinical settings. Our expanding knowledge of RNS and ROS involvement in cardiovascular disorders has made it possible to develop redox biomarkers as diagnostic and prognostic tools. Overcoming the challenges associated with their utility and utilizing advanced detection techniques, which will improve their clinical applicability, will ultimately benefit the management and treatment of cardiovascular conditions.

Adaptor molecules mediate negative regulation of macrophage inflammatory pathways: a closer look.

Macrophages play a central role in initiating, maintaining, and terminating inflammation. For that, macrophages respond to various external stimuli in changing environments through signaling pathways that are tightly regulated and interconnected. This process involves, among others, autoregulatory loops that activate and deactivate macrophages through various cytokines, stimulants, and other chemical mediators. Adaptor proteins play an indispensable role in facilitating various inflammatory signals. These proteins are dynamic and flexible modulators of immune cell signaling and act as molecular bridges between cell surface receptors and intracellular effector molecules. They are involved in regulating physiological inflammation and also contribute significantly to the development of chronic inflammatory processes. This is at least partly due to their involvement in the activation and deactivation of macrophages, leading to changes in the macrophages' activation/phenotype. This review provides a comprehensive overview of the 20 adaptor molecules and proteins that act as negative regulators of inflammation in macrophages and effectively suppress inflammatory signaling pathways. We emphasize the functional role of adaptors in signal transduction in macrophages and their influence on the phenotypic transition of macrophages from pro-inflammatory M1-like states to anti-inflammatory M2-like phenotypes. This endeavor mainly aims at highlighting and orchestrating the intricate dynamics of adaptor molecules by elucidating the associated key roles along with respective domains and opening avenues for therapeutic and investigative purposes in clinical practice.

The indispensability of macrophage adaptor proteins in chronic inflammatory diseases.

Adaptor proteins represent key signalling molecules involved in regulating immune responses. The host's innate immune system recognizes pathogens via various surface and intracellular receptors. Adaptor molecules are centrally involved in different receptor-mediated signalling pathways, acting as bridges between the receptors and other molecules. The presence of adaptors in major signalling pathways involved in the pathogenesis of various chronic inflammatory diseases has drawn attention toward the role of these proteins in such diseases. In this review, we summarize the importance and roles of different adaptor molecules in macrophage-mediated signalling in various chronic disease states. We highlight the mechanistic roles of adaptors and how they are involved in protein-protein interactions (PPI) via different domains to carry out signalling. Hence, we also provide insights into how targeting these adaptor proteins can be a good therapeutic strategy against various chronic inflammatory diseases.

Implications of metabolic dysfunction associated fatty liver disease in COVID-19.

Metabolic associated fatty liver disorder (MAFLD) characterizes the contributing etiologies (i.e., type 2 diabetes mellitus, metabolic syndrome, overweight) of individuals with fatty liver disease that affects 1/3rd of the world population. In 2020, the coronavirus disease 2019 (COVID-19) crisis was unprecedented, and people with different comorbidities became more susceptible to the infection caused by severe acute respiratory syndrome coronavirus 2. MAFLD patients are frequently obese with added metabolic menace like diabetes, hypertension, and dyslipidemia leading to greater jeopardy of COVID-19. MAFLD patients are 4 to 6-fold more prone towards infections. COVID-19 induces liver injury with elevated levels of aspartate aminotransferase and alanine aminotransferase and insignificantly elevated bilirubin. Hence, MAFLD in COVID-19 patients worsens the condition significantly. The evidence highlighting the interaction between MAFLD and altered liver functioning in COVID-19 suggested that COVID-19 patients with pre-existing MAFLD are at greater risk of morbidity or intensive care unit admission. Direct hepatic injury, enhanced levels of inflammatory cytokines, declined hepatic mitochondrial activity, and compromised immunity are considered as some underlying mechanisms. The main focus of this review is to discuss the implications of metabolic dysfunction associated with fatty liver disease in COVID-19 patients. The review systematically analyzes the effect of striking two worldwide pandemics (MAFLD and COVID-19) together in the present era.