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1.
J Immunotoxicol ; 18(1): 23-29, 2021 12.
Article in English | MEDLINE | ID: covidwho-1593522

ABSTRACT

The coronavirus SARS-CoV-2 of 2019 (COVID-19) causes a pandemic that has been diagnosed in more than 70 million people worldwide. Mild-to-moderate COVID-19 symptoms include coughing, fever, myalgia, shortness of breath, and acute inflammatory lung injury (ALI). In contrast, acute respiratory distress syndrome (ARDS) and respiratory failure occur in patients diagnosed with severe COVID-19. ARDS is mediated, at least in part, by a dysregulated inflammatory response due to excessive levels of circulating cytokines, a condition known as the "cytokine-storm syndrome." Currently, there are FDA-approved therapies that attenuate the dysregulated inflammation that occurs in COVID-19 patients, such as dexamethasone or other corticosteroids and IL-6 inhibitors, including sarilumab, tocilizumab, and siltuximab. However, the efficacy of these treatments have been shown to be inconsistent. Compounds that activate the vagus nerve-mediated cholinergic anti-inflammatory reflex, such as the α7 nicotinic acetylcholine receptor agonist, GTS-21, attenuate ARDS/inflammatory lung injury by decreasing the extracellular levels of high mobility group box-1 (HMGB1) in the airways and the circulation. It is possible that HMGB1 may be an important mediator of the "cytokine-storm syndrome." Notably, high plasma levels of HMGB1 have been reported in patients diagnosed with severe COVID-19, and there is a significant negative correlation between HMGB1 plasma levels and clinical outcomes. Nicotine can activate the cholinergic anti-inflammatory reflex, which attenuates the up-regulation and the excessive release of pro-inflammatory cytokines/chemokines. Therefore, we hypothesize that low molecular weight compounds that activate the cholinergic anti-inflammatory reflex, such as nicotine or GTS-21, may represent a potential therapeutic approach to attenuate the dysregulated inflammatory responses in patients with severe COVID-19.


Subject(s)
Benzylidene Compounds/pharmacology , COVID-19/drug therapy , Cholinergic Agents/pharmacology , Inflammation/drug therapy , Nicotine/metabolism , Pyridines/pharmacology , SARS-CoV-2/physiology , Tobacco Use Disorder/drug therapy , Antibodies, Monoclonal, Humanized/therapeutic use , Cigarette Smoking/adverse effects , Dexamethasone/therapeutic use , HMGB1 Protein/blood , Humans , Pandemics , alpha7 Nicotinic Acetylcholine Receptor/agonists
2.
Cell Biol Int ; 45(7): 1533-1545, 2021 Jul.
Article in English | MEDLINE | ID: covidwho-1141294

ABSTRACT

Polymorphonuclear neutrophilic granulocytes (PMNs) are the largest proportion of leukocytes in adult human blood that perform numerous functions, including phagocytosis, degranulation, generation of reactive oxygen species, and NETosis. Excessive neutrophil activity associates with hyperinflammation and tissue damage during pathologies such as inflammatory bowel disease, diabetes mellitus, tuberculosis, and coronavirus disease 2019. Nicotinic acetylcholine receptors (nAChRs) can modulate immune cells, including neutrophils, functions, therefore, nAChR ligands are considered as the potent agents for therapy of inflammation. Earlier it was shown, that about 30% of PMNs from the acute inflammatory site responded to nicotine by calcium spikes. In this study, we studied the generation of calcium spikes in murine granulocytes with different maturity level (evaluated by Gr-1 expression) isolated from bone marrow in response to ligands of nAChRs in control and under chronic nicotine consumption. It was found that nearly 20%-25% cells in the granulocyte population responded to nicotine or selective antagonists of different type of nAChRs (α-cobratoxin, GIC, and Vc1.1). We demonstrated that in the control group Ca2+ -mobilizing activity was regulated through α7 and α9α10 nAChRs in immature granulocytes (Gr-1int ), whereas in mature granulocytes (Gr-1hi ) it was regulated through α7, α3ß2, and α9-contained nAChRs. Sensitivity of PMNs to nicotine depended on their maturity level after chronic nicotine consumption. Gr-1int cells responded to nicotine through α7 and α9-contained nAChRs, while Gr-1hi did not respond to nicotine. Thus, calcium response to nAChR ligands in bone marrow PMNs depends on their maturity level.


Subject(s)
Antigens, Ly/metabolism , Bone Marrow Cells/drug effects , Calcium Signaling/drug effects , Calcium/metabolism , Cholinergic Agents/pharmacology , Granulocytes/drug effects , Receptors, Nicotinic/drug effects , Animals , Bone Marrow Cells/metabolism , Cells, Cultured , Granulocytes/metabolism , Ligands , Male , Mice, Inbred BALB C , Nicotine/pharmacology , Nicotinic Agonists/pharmacology , Nicotinic Antagonists/pharmacology , Receptors, Nicotinic/metabolism
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