Too hard to die: Exercise training mediates specific and immediate SARS-CoV-2 protection

Anexelekto (AXL) no more: microRNA-155 (miR-155) controls the "Uncontrolled" in SARS-CoV-2

AXL is the gene that encodes the Anexelekto (AXL) receptor tyrosine kinase that demonstrates significant roles in various cellular processes, including cell growth, survival, and migration. Anexelekto is a Greek word meaning excessive and uncontrolled, semantically implying the crucial involvement of AXL in cancer and immune biology, and in promoting cancer metastasis. AXL overexpression appears to drive epithelial to mesenchymal transition, tumor angiogenesis, decreased antitumor immune response, and resistance to therapeutic agents. Recently, AXL has been reported to play important roles in several viral infections, including SARS-CoV-2. We have previously outlined the importance of microRNAs (miRNAs, miRs) and especially miR-155 in SARS-CoV-2 pathophysiology through regulation of the Renin-Angiotensin Aldosterone System (RAAS) and influence on several aspects of host innate immunity. MiRNAs are negative regulators of gene expression, decreasing the stability of target RNAs or limiting their translation and, enthrallingly, miR-155 is also involved in AXL homeostasis-both endogenously and pharmaceutically using repurposed drugs (e.g., metformin)-highlighting thrifty evolutionary host innate immunity mechanisms that successfully can thwart viral entry and replication. Cancer, infections, and immune system disturbances will increasingly involve miRNA diagnostics and therapeutics in the future.

MicroRNA-155 mediates endogenous angiotensin II type 1 receptor regulation: implications for innovative type 2 diabetes mellitus management

Type 2 diabetes mellitus (T2DM) is a lifelong condition and a threat to human health. Thorough understanding of its pathogenesis is acutely needed in order to devise innovative, preventative, and potentially curative pharmacological interventions. MicroRNAs (miRNA), are small, non-coding, one-stranded RNA molecules, that can target and silence around 60% of all human genes through translational repression. MiR-155 is an ancient, evolutionarily well-conserved miRNA, with distinct expression profiles and multifunctionality, and a target repertoire of over 241 genes involved in numerous physiological and pathological processes including hematopoietic lineage differentiation, immunity, inflammation, viral infections, cancer, cardiovascular conditions, and particularly diabetes mellitus. MiR-155 Levels are progressively reduced in aging, obesity, sarcopenia, and T2DM. Thus, the loss of coordinated repression of multiple miR-155 targets acting as negative regulators, such as C/EBPβ, HDAC4, and SOCS1 impacts insulin signaling, deteriorating glucose homeostasis, and causing insulin resistance (IR). Moreover, deranged regulation of the renin angiotensin aldo-sterone system (RAAS) through loss of Angiotensin II Type 1 receptor downregulation, and negated repression of ETS-1, results in unopposed detrimental Angiotensin II effects, further promoting IR. Finally, loss of BACH1 and SOCS1 repression abolishes cytoprotective, anti-oxidant, anti-apoptotic, and anti-inflammatory cellular pathways, and promotes β-cell loss. In contrast to RAAS inhibitor treatments that further decrease already reduced miR-155 Levels, strategies to increase an ailing miR-155 production in T2DM, e.g., the use of metformin, mineralocorticoid receptor blockers (spironolactone, eplerenone, finerenone), and verapamil, alone or in various combinations, represent current treatment options. In the future, direct tissue delivery of miRNA analogs is likely.

Exercise intensities modulate ACE2/MasR/eNOS pathway in male Wistar rat's lung

Specific exercise intensities could improve lung vascular function by increasing nitric oxide (NO). The ACE2/MasR/eNOS axis is one of the pathways facilitating NO synthesis. This study examines the effect of different intensities of aerobic training on the ACE2/MasR/eNOS axis and histology of lung muscular arteries. Male Wistar rats were used in this study and randomized into control and exercise groups receiving low-, moderate-, and high-intensity training. The training was conducted for 30 min daily, five times a week, for 8 weeks. We observed that different exercise intensities affect the ACE2/MasR/eNOS pathway differently. Compared to control, high-intensity aerobic exercise significantly increased ACE2, Mas receptor (MasR), and eNOS mRNA expressions (p < 0.01). Moderate-intensity exercise significantly increased MasR and eNOS mRNA expressions compared to the control (p < 0.05), and this intensity also increased ACE2 mRNA but not significantly. Low-intensity exercise increased ACE2, MasR, and eNOS mRNA expressions but not significantly. Low-, moderate-, or high-intensity exercises reduced the medial wall thickness of the lung muscular arteries but not significantly. In conclusion, high-intensity exercise may induce NO synthesis in the lung by increasing mRNA expression of ACE2, MasR, and eNOS without decreasing the medial wall thickness of the muscular artery. Thus, high-intensity exercise may be the optimal intensity to improve NO synthesis and vascular function in the lung.

Organokines in COVID-19: A Systematic Review

Coronavirus disease 2019 (COVID-19) is a viral infection caused by SARS-CoV-2 that induces a generalized inflammatory state. Organokines (adipokines, osteokines, myokines, hepatokines, and cardiokines) can produce beneficial or harmful effects in this condition. This study aimed to systematically review the role of organokines on COVID-19. PubMed, Embase, Google Scholar, and Cochrane databases were searched, the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed, and 37 studies were selected, comprising more than 2700 individuals infected with the virus. Among COVID-19 patients, organokines have been associated with endothelial dysfunction and multiple organ failure due to augmented cytokines and increased SARS-CoV-2 viremia. Changes in the pattern of organokines secretion can directly or indirectly contribute to aggravating the infection, promoting immune response alterations, and predicting the disease progression. These molecules have the potential to be used as adjuvant biomarkers to predict the severity of the illness and severe outcomes.

Successful lifestyle modifications may underlie umbilical cord-mesenchymal stromal cell effects in type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) is a lifelong condition and a grave threat to human health. Innovative efforts to relieve its detrimental effects are acutely needed. The sine qua non in T2DM management is consistent adherence to a prudent lifestyle and nutrition, combined with aerobic and resistance exercise regimens, together repeatedly shown to lead to complete reversal and even long-term remission. Non-adherence to the above lifestyle adjustments condemns any treatment effort and ultimately the patient to a grim fate. It is thus imperative that every study evaluating the effects of innovative interventions in T2DM objectively compares the novel treatment modality to lifestyle modifications, preferably through double-blind controlled randomization, before claiming efficacy.

Irisin: An anti-inflammatory exerkine in aging and redox-mediated comorbidities

Human beings lead largely sedentary lives. From an evolutionary perspective, such lifestyle is not beneficial to health. Exercise can promote many enabling pathways, particularly through circulating exerkines, to optimize individual health and quality of life. Such benefits might explain the protective effects of exercise against aging and noncommunicable diseases. Nevertheless, the miRNA-mediated molecular mechanisms and exerkine interorgan crosstalk that underlie the beneficial effects of exercise remain poorly understood. In this mini review, we focused on the exerkine, irisin, mainly produced by muscle contraction during adaptation to exercise and its beneficial effects on body homeostasis. Herein, the complex role of irisin in metabolism and inflammation is described, including its subsequent effects on thermogenesis through browning to control obesity and improve glycemic regulation for diabetes mellitus control, its potential to improve cognitive function (via brain derived neurotrophic factor), and its pathways of action and role in aging.