SARS-CoV-2 Infection-Induced Alterations in ADAR Editing Patterns Differ Between Patients Who Developed Critical Compared to Non-Critical COVID-19

Abstract

COVID-19, caused by the SARS-CoV-2 virus, has a wide spectrum of clinical presentations even among individuals with similar demographics. Disease severity has been linked with viral-mediated expression of interferons and interferon-stimulated genes. Among the interferon-stimulated genes are members of adenosine deaminases acting on the RNA (ADAR) family that contribute to transcriptome diversity and modulate immune response. Previous studies identified altered ADAR expression and editing patterns during SARS-CoV-2 infection, although it remains unclear whether ADAR expression and activity differ between patients with varying severities of COVID-19. We used whole-blood transcriptomes from individuals with critical or non-critical COVID-19 and matched for age, sex, and presence of comorbidities. Results show differential expression of numerous genes, including those involved in neutrophil degranulation, and upregulation of ADAR1 and its isoform ADARp110 in patients with critical COVID-19. We identified severity-specific editing events, including nonsynonymous edits, within distinct biological pathways. Differentially edited sites—that could serve as molecular markers for COVID-19 severity—were found within genes enriched in signal transduction, RNA and protein metabolism, and inflammatory pathways. Our results demonstrate differences in expression and editing patterns of ADARs between critical and non-critical patients, supporting a potential role of ADAR editing in COVID-19 pathogenesis.