Single-nucleus transcriptome analysis of human brain immune response in patients with severe COVID-19
John F. Fullard, Hao-Chih Lee, Georgios Voloudakis, Shengbao Suo, Behnam Javidfar, Zhiping Shao, Cyril Peter, Wen Zhang, Shan Jiang, André Corvelo, Heather Wargnier, Emma Woodoff‐Leith, Dushyant P. Purohit, Sadhna Ahuja, Nadejda M. Tsankova, Nathalie Jetté, Gabriel E. Hoffman, Schahram Akbarian, Mary Fowkes, John F. Crary, Guo‐Cheng Yuan, Panos Roussos
Abstract
BACKGROUND: Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, has been associated with neurological and neuropsychiatric illness in many individuals. We sought to further our understanding of the relationship between brain tropism, neuro-inflammation, and host immune response in acute COVID-19 cases. METHODS: Three brain regions (dorsolateral prefrontal cortex, medulla oblongata, and choroid plexus) from 5 patients with severe COVID-19 and 4 controls were examined. The presence of the virus was assessed by western blot against viral spike protein, as well as viral transcriptome analysis covering > 99% of SARS-CoV-2 genome and all potential serotypes. Droplet-based single-nucleus RNA sequencing (snRNA-seq) was performed in the same samples to examine the impact of COVID-19 on transcription in individual cells of the brain. RESULTS: Quantification of viral spike S1 protein and viral transcripts did not detect SARS-CoV-2 in the postmortem brain tissue. However, analysis of 68,557 single-nucleus transcriptomes from three distinct regions of the brain identified an increased proportion of stromal cells, monocytes, and macrophages in the choroid plexus of COVID-19 patients. Furthermore, differential gene expression, pseudo-temporal trajectory, and gene regulatory network analyses revealed transcriptional changes in the cortical microglia associated with a range of biological processes, including cellular activation, mobility, and phagocytosis. CONCLUSIONS: Despite the absence of detectable SARS-CoV-2 in the brain at the time of death, the findings suggest significant and persistent neuroinflammation in patients with acute COVID-19.