Molecular and Cellular Mechanisms Underlying Neurological and Neuropsychological Manifestations of COVID-19.

OBJECTIVE: Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is associated with a wide range of neurological symptoms and neuropsychiatric conditions. SARS-CoV-2 shows various degrees of neurotropism. SARS-CoV-2 primarily targets respiratory and gastrointestinal tracts; however, it can affect other organs. Neurological and neuropsychological manifestations of COVID-19 have been reported. Several mechanisms are involved in these manifestations in COVID-19. Therefore, the present narrative review will take account of mechanisms underlying the neurological and neuropsychological manifestations in COVID-19. METHODS: A literature search for relevant articles in different databases was made with a focus on recent publications for this narrative review. RESULTS: Inflammation and thrombosis have been suggested to be mechanisms contributing to these manifestations. Also, renin-angiotensin system (RAS), transmembrane serine protease 2 (TMPRSS2), cathepsin B and L, furin, neuropilin-1 (NRP1), and sterile alpha motif and HD domain-containing protein 1 (SAMHD1) have been proposed to be involved in pathogenesis of SARS-CoV-2. Moreover, cluster of differentiation 147 (CD147) and dipeptidyl peptidase 4 (DPP4) have been suggested to have a role in SARS-CoV-2 entry into the central nervous system (CNS). CONCLUSION: Further investigation on the underlying mechanisms leading to SARS-CoV-2-associated neurological and neuropsychological manifestations is pivotal. Insights into these mechanisms will help the treatment strategies for patients with COVID-19 and such manifestations.