Highlights d scRNA-seq on nasopharyngeal swabs of 58 COVID-19 and healthy participants d SARS-CoV-2 induces ciliated cell loss with secretory and deuterosomal expansion d Early, muted anti-viral responses in nasal epithelia in severe COVID-19 d Host-virus co-detection maps cell tropism and intrinsic responses to SARS-CoV-2

Background Several lines of evidence suggest dysfunction of the GABAergic system in Major Depressive Disorder (MDD). Neuroimaging studies report reduced levels of GABA in the dorsolateral prefrontal and occipital cortex of depressed patients. Our previous postmortem study revealed a reduction in the density and size of Calbindin-immunoreactive (CB-IR) GABAergic neurons in the prefrontal cortex in MDD. The goal of this study was to test whether the changes in CB-IR neurons can also be detected in the occipital cortex where neuroimaging studies report a prominent GABA decrease. Methods A three-dimensional cell counting probe was used to assess the cell packing density and size of CB-IR neurons in layer II of the occipital cortex in 10 MDD subjects, and 10 psychiatrically healthy controls. Results The density of CB-IR neurons was significantly decreased by 28% in MDD subjects as compared to the control group. The size of CB-IR neurons was unchanged in MDD subjects when compared to controls. Conclusions The reduction in the density of CB-IR GABAergic neurons in the occipital cortex in depression is similar to that observed previously in the prefrontal cortex. Deficit in cortical GABAergic interneurons may contribute to the low GABA levels detected in neuroimaging studies in MDD patients.

To investigate the relationship between intestinal microbiota and SARS-CoV-2-mediated pathogenicity in a United States, majority African American cohort. We prospectively collected fecal samples from 50 SARS-CoV-2 infected patients, 9 SARS-CoV-2 recovered patients, and 34 uninfected subjects seen by the hospital with unrelated respiratory medical conditions (controls). 16S rRNA sequencing and qPCR analysis was performed on fecal DNA/RNA. The fecal microbial composition was found to be significantly different between SARS-CoV-2 patients and controls (PERMANOVA FDR-P = .004), independent of antibiotic exposure. Peptoniphilus, Corynebacterium and Campylobacter were identified as the three most significantly enriched genera in COVID-19 patients compared to controls. Actively infected patients were also found to have a different gut microbiota than recovered patients (PERMANOVA FDR-P = .003), and the most enriched genus in infected patients was Campylobacter, with Agathobacter and Faecalibacterium being enriched in the recovered patients. No difference in microbial community structure between recovered patients and uninfected controls was observed, nor a difference in alpha diversity between the three groups. 24 of the 50 COVID-19 patients (48%) tested positive via RT-qPCR for fecal SARS-CoV-2 RNA. A significant difference in gut microbial composition between SARS-CoV-2 positive and negative samples was observed, with Klebsiella and Agathobacter being enriched in the positive cohort. No significant associations between microbiome composition and disease severity was found. The intestinal microbiota is sensitive to the presence of SARS-CoV-2, with increased relative abundance of genera (Campylobacter, Klebsiella) associated with gastrointestinal (GI) disease. Further studies are needed to investigate the functional impact of SARS-CoV-2 on GI health.