Air pollution particulate matter as a potential carrier of SARS-CoV-2 to the nervous system and/or neurological symptom enhancer: arguments in favor

Entry receptor for SARS-CoV-2 is expressed in nasal epithelial cells, and nasal delivery pathway can be a key feature of transmission. Here, a possibility of interaction of SARS-CoV-2 with air pollution particulate matter (PM) was considered. It was shown in our recent studies that water-suspended plastic and wood smoke aerosol PM and carbon-containing nanoparticles from burning organics can interact with the plasma membrane of brain nerve terminals presumably due to their lipid components. COVID-19 patients have neurological symptoms, viral particles were found in the brain, SARS-CoV-2 enters the cells via fusion of lipid viral envelope with the plasma membranes of infected cells, and so viral envelop can contain lipid components of the host neuronal membranes. Therefore, interaction of SARS-CoV-2 envelope with PM is possible in water surrounding. After drying, PM can serve as a carrier for transmission of SARS-CoV-2 immobilized at their surface. Moreover, PM and SARS-CoV-2 per se can enter human organism during nasal inhalation, and they both use the same nose-to-brain delivery pathways moving along axons directly to the brain, influencing the nervous system and exocytosis/endocytosis in nerve cells. Thus, PM can aggravate neurological symptoms of SARS-CoV-2 and vice versa, due to their identical nose-to-brain delivery mechanism and possible interference of neuronal effects. In addition, different types of PM because of their ability to interact with the plasma membranes of nerve cells can facilitate unspecific SARS-CoV-2 entrance to the cells, and can influence envelope features of SARS-CoV-2. Detailed studies are required to analyze interaction of SARS-CoV-2 with PM.