Opposite Effect of Thyroid Hormones on Oxidative Stress and on Mitochondrial Respiration in COVID-19 Patients

Nitric oxide as a double-edged sword in pulmonary viral infections: Mechanistic insights and potential therapeutic implications

In the face of the global pandemic caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), researchers are tirelessly exploring novel therapeutic approaches to combat coronavirus disease 2019 (COVID-19) and its associated complications. Nitric oxide (NO) has appeared as a multifaceted signaling mediator with diverse and often contrasting biological activities. Its intricate biochemistry renders it a crucial regulator of cardiovascular and pulmonary functions, immunity, and neurotransmission. Perturbations in NO production, whether excessive or insufficient, contribute to the pathogenesis of various diseases, encompassing cardiovascular disease, pulmonary hypertension, asthma, diabetes, and cancer. Recent investigations have unveiled the potential of NO donors to impede SARS-CoV- 2 replication, while inhaled NO demonstrates promise as a therapeutic avenue for improving oxygenation in COVID-19-related hypoxic pulmonary conditions. Interestingly, NO's association with the inflammatory response in asthma suggests a potential protective role against SARS-CoV-2 infection. Furthermore, compelling evidence indicates the benefits of inhaled NO in optimizing ventilation-perfusion ratios and mitigating the need for mechanical ventilation in COVID-19 patients. In this review, we delve into the molecular targets of NO, its utility as a diagnostic marker, the mechanisms underlying its action in COVID-19, and the potential of inhaled NO as a therapeutic intervention against viral infections. The topmost significant pathway, gene ontology (GO)-biological process (BP), GO-molecular function (MF) and GO-cellular compartment (CC) terms associated with Nitric Oxide Synthase (NOS)1, NOS2, NOS3 were arginine biosynthesis (p-value = 1.15 x 10-9) regulation of guanylate cyclase activity (p-value = 7.5 x 10-12), arginine binding (p-value = 2.62 x 10-11), vesicle membrane (p-value = 3.93 x 10-8). Transcriptomics analysis further validates the significant presence of NOS1, NOS2, NOS3 in independent COVID-19 and pulmonary hypertension cohorts with respect to controls. This review investigates NO's molecular targets, diagnostic potentials, and therapeutic role in COVID-19, employing bioinformatics to identify key pathways and NOS isoforms' significance.

To Be Frail or Not to Be Frail: This Is the Question-A Critical Narrative Review of Frailty

Many factors have contributed to rendering frailty an emerging, relevant, and very popular concept. First, many pandemics that have affected humanity in history, including COVID-19, most recently, have had more severe effects on frail people compared to non-frail ones. Second, the increase in human life expectancy observed in many developed countries, including Italy has led to a rise in the percentage of the older population that is more likely to be frail, which is why frailty is much a more common concern among geriatricians compared to other the various health-care professionals. Third, the stratification of people according to the occurrence and the degree of frailty allows healthcare decision makers to adequately plan for the allocation of available human professional and economic resources. Since frailty is considered to be fully preventable, there are relevant consequences in terms of potential benefits both in terms of the clinical outcome and healthcare costs. Frailty is becoming a popular, pervasive, and almost omnipresent concept in many different contexts, including clinical medicine, physical health, lifestyle behavior, mental health, health policy, and socio-economic planning sciences. The emergence of the new "science of frailty" has been recently acknowledged. However, there is still debate on the exact definition of frailty, the pathogenic mechanisms involved, the most appropriate method to assess frailty, and consequently, who should be considered frail. This narrative review aims to analyze frailty from many different aspects and points of view, with a special focus on the proposed pathogenic mechanisms, the various factors that have been considered in the assessment of frailty, and the emerging role of biomarkers in the early recognition of frailty, particularly on the role of mitochondria. According to the extensive literature on this topic, it is clear that frailty is a very complex syndrome, involving many different domains and affecting multiple physiological systems. Therefore, its management should be directed towards a comprehensive and multifaceted holistic approach and a personalized intervention strategy to slow down its progression or even to completely reverse the course of this condition.

Bidirectional association between hypothyroidism and myasthenia gravis: a Mendelian randomized study

OBJECTIVES

Although observational studies have suggested a link between hypothyroidism and myasthenia gravis (MG), a causal relationship has not been established. We aimed to investigate the causal association using a two-sample Mendelian randomization (MR) study.

METHODS

Using summary statistics from genome-wide association studies involving 494,577 and 38,243 individuals, single-nucleotide polymorphisms exhibiting no linkage disequilibrium (r2 ≤ 0.001) and displaying significant differences (p ≤ 5 × 10-8) were selected for hypothyroidism and MG. To assess the potential causality relationship between hypothyroidism and MG, MR analysis was conducted using inverse variance weighted (IVW), weighted median method, and MR-Egger. The MR-Egger regression, heterogeneity test, pleiotropy test, and leave-one-out sensitivity test were employed to examine sensitivity analyses. In addition, validation datasets were used to validate the relevant results.

RESULTS

Genetic liability to hypothyroidism was positively associated with MG (IVW, OR: 1.36, 95% CI: 1.17-1.58, p = 7.53 × 10-05; weighted median, OR: 1.19, 95% CI: 0.70-2.02, p = 0.522; MR-Egger, OR: 1.19, 95% CI: 0.98-1.45, p = 0.080). Among the three MR methods, the correlation between hypothyroidism and MG genetic prediction was consistent. The independent validation set (IVW, OR: 466.47, 95% CI: 4.70 -46,285.95, p = 0.01) further supported this. Additionally, bidirectional studies showed that using IVW, there was no reverse causality (OR: 1.104, 95%CI: 0.96-1.27, p = 0.170).

DISCUSSION

This MR study showed that hypothyroidism can increase the risk of MG. Further investigation into the underlying mechanisms of this potential causality is warranted to offer novel therapeutic options for MG in the future.

Targeting Translation and the Cell Cycle Inversely Affects CTC Metabolism but Not Metastasis

Melanoma brain metastasis (MBM) is significantly associated with poor prognosis and is diagnosed in 80% of patients at autopsy. Circulating tumor cells (CTCs) are "seeds" of metastasis and the smallest functional units of cancer. Our multilevel approach has previously identified a CTC RPL/RPS gene signature directly linked to MBM onset. We hypothesized that targeting ribogenesis prevents MBM/metastasis in CTC-derived xenografts. We treated parallel cohorts of MBM mice with FDA-approved protein translation inhibitor omacetaxine with or without CDK4/CDK6 inhibitor palbociclib, and monitored metastatic development and cell proliferation. Necropsies and IVIS imaging showed decreased MBM/extracranial metastasis in drug-treated mice, and RNA-Seq on mouse-blood-derived CTCs revealed downregulation of four RPL/RPS genes. However, mitochondrial stress tests and RT-qPCR showed that omacetaxine and palbociclib inversely affected glycolytic metabolism, demonstrating that dual targeting of cell translation/proliferation is critical to suppress plasticity in metastasis-competent CTCs. Equally relevant, we provide the first-ever functional metabolic characterization of patient-derived circulating neoplastic cells/CTCs.

Melissa officinalis extract suppresses endoplasmic reticulum stress-induced apoptosis in the brain of hypothyroidism-induced rats exposed to γ-radiation

The purpose of this study was to demonstrate the neuroprotective effect of Melissa officinalis extract (MEE) against brain damage associated with hypothyroidism induced by propylthiouracil (PTU) and/or γ-radiation (IR) in rats. Hypothyroidism induction and/or exposure to IR resulted in a significant decrease in the serum levels of T3 and T4 associated with increased levels of lipid peroxidation end product, malondialdehyde (MDA), and nitrites (NO) in the brain tissue homogenate. Also, hypothyroidism and /or exposure to IR markedly enhance the endoplasmic reticulum stress by upregulating the gene expressions of the protein kinase RNA-like endoplasmic reticulum kinase (PERK), activated transcription factor 6 (ATF6), endoplasmic reticulum-associated degradation (ERAD), and CCAAT/enhancer-binding protein homologous protein (CHOP) in the brain tissue homogenate associated with a proapoptotic state which indicated by the overexpression of Bax, BCl2, and caspase-12 that culminates in brain damage. Meanwhile, the PTU and /or IR-exposed rats treated with MEE reduced oxidative stress and ERAD through ATF6. Also, the MEE treatment prevented the Bax and caspase-12 gene expression from increasing. This treatment in hypothyroid animals was associated with neuronal protection as indicated by the downregulation in the gene expressions of the microtubule-associated protein tau (MAPT) and amyloid precursor protein (APP) in the brain tissue. Furthermore, the administration of MEE ameliorates the histological structure of brain tissue. In conclusion, MEE might prevent hypothyroidism-induced brain damage associated with oxidative stress and endoplasmic reticulum stress.