Project Summary: DNA 5'-C-phosphate-G-3' (CpG) methylation is a covalent epigenetic modification that regulates gene expression and is highly sensitive to age and environmental factors. Critically ill patients exhibit altered circulating blood DNA methylation profiles. We have recently reported a large scale methylome analysis of COVID-19 in association with clinical outcomes, which suggests an epigenetic regulation of genes controlling disease severity. Recent evidence indicates that many surviving COVID-19 patients develop long term dysfunctions and the NIH-NHLBI has recently launched an initiative to elucidate the nature of Post-Acute Sequelae of SARS-CoV-2 Infection (PASC). It is currently unknown if the rapid methylome regulation evoked by acute illness persist after SARS-CoV-2 resolution. Such persistence could underpin long term sequela associated with this condition. Because DNA methylation is a relatively stable DNA chemical modification that could influence long-term gene expression profiles and given that we recently found that multiple regions developed during acute illness persist differentially methylated one year after hospital discharge, we hypothesize that COVID-19 infection leads to enduring DNA methylation abnormalities that remain after resolution of acute illness in association with the post-COVID-19 clinical profile. In this application, we plan to conduct whole genome DNA methylation and RNA sequencing of circulating leucocytes to establish sub phenotypes of PASC, predict future PASC development in the acute COVID-19, and determine which circulating leucocyte lineage contributes to that enduring methylome.

Project Narrative: Given the strong impact of COVID-19 infection in the Post-Acute Sequelae of SARS-CoV-2 Infection (PASC), the proposed research is relevant to public health because the elucidation of the mechanisms regulating persistent DNA methylation in inflammatory cells are ultimately expected to lead to better understanding of the process’ pathophysiology. Moreover, the identification of a novel phenotype as proposed here could facilitate early targeting of a subgroup of vulnerable patients, which represents a top priority of the NHLBI mission.