Tunneling nanotubes provide a route for SARS-CoV-2 spreading
https://www.science.org/doi/10.1126/sciadv.abo0171
Abstract
Neurological manifestations of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection represent a major issue in long coronavirus disease. How SARS-CoV-2 gains access to the brain and how infection leads to neurological symptoms are not clear because the principal means of viral entry by endocytosis, the angiotensin-converting enzyme 2 receptor, are barely detectable in the brain. We report that human neuronal cells, nonpermissive to infection through the endocytic pathway, can be infected when cocultured with permissive infected epithelial cells. SARS-CoV-2 induces the formation of tunneling nanotubes (TNTs) and exploits this route to spread to uninfected cells. In cellulo correlative fluorescence and cryo–electron tomography reveal that SARS-CoV-2 is associated with TNTs between permissive cells. Furthermore, multiple vesicular structures such as double-membrane vesicles, sites of viral replication, are observed inside TNTs between permissive and nonpermissive cells. Our data highlight a previously unknown mechanism of SARS-CoV-2 spreading, likely used as a route to invade nonpermissive cells and potentiate infection in permissive cells.
Age-related Smell and Taste Impairments and Vitamin D Associations in the U.S. Adults National Health and Nutrition Examination Survey
Abstract
Smell and taste decline with aging, and markedly deteriorate when nutritional deficiencies occur. This study aims to examine the associations between Vitamin D (VD) deficiency and smell and taste impairments among adults. This paper details a cross-sectional study utilizing data from the US National Health and Nutrition Examination Survey (NHANES, 2013–2014.). Smell impairment was assessed by the Pocket Smell Test and defined as failing to correctly identify six or more of the eight odors. Taste impairment was defined as failing to correctly identify quinine or sodium chloride. VD was measured as serum 25-hydroxyvitamin. Multivariable weighted logistic regressions were utilized. Adjusted odds ratio (OR) and 95% confidence interval (CI) were presented. Overall, 2216 (smell sample) and 2636 (taste sample) participants were included, aged between 40 and 80 years old. Of those, 18.3% had taste impairment, 12.2% had smell impairment, and 20% had VD deficiency (<20 ng/mL). Compared to participants with sufficient VD (>30 ng/mL), those with VD deficiency were more likely by 39% to report a higher prevalence of smell impairment (OR = 1.39, 95%CI: 1.02–1.89); and only participants aged 70–80 years with VD inadequacy (20–30 ng/mL) were more likely by 96% to report a higher prevalence of taste impairment (OR = 1.96, 95%CI: 1.35–1.85). VD may have a significant role in age-related smell impairment in adults aged 40 years or older, and in age-related taste impairment in the elderly aged 70–80 years.