Interplay between TET1-mediated epigenomic mechanisms and m6A RNA modification in pulmonary inflammation induced by particulate matter

About This Grant

Project Summary Up to 40% of the U.S. population is exposed to unhealthy air pollution, with particulate matter (PM) being a major contributor. PM exposure induces oxidative stress and inflammation and leads to severe lung diseases, which is mediated by the Aryl-hydrocarbon receptor (AhR) pathway and epithelial cytokines. Despite growing evidence, the underlying molecular mechanisms are not fully understood, limiting the development of targeted interventions. Emerging research suggests that PM exposure influences N6-methyladenosine (m6A) RNA modification, which regulates RNA stability and translation, through altering the expression of proteins adding, removing and binding to this modification ("Readers", "Writers", and "Erasers", abbreviated as "RWEs"). Intriguingly, RNA m6A "read- ers" can recruit epigenomic regulators such as DNA demethylase TET1 to alter DNA methylation and chromatin accessibility, highlighting crosstalk between RNA m6A and TET1-mediated epigenomic mechanisms. Whether RNA m6A interacts with TET1 and TET1-mediated epigenomic mechanisms in airway epithelial cells, how they interact and contribute to PM-induced lung inflammation remain as significant research gaps. In response to NIEHS RFA-ES-25-001 (EPCOT), this proposal aims to investigate the interactions between TET1-mediated epigenomic mechanisms and RNA m6A in PM-induced lung inflammation. Our preliminary data established a novel role of TET1 in protecting against PM-induced lung inflammation and remodeling, through promoting the expression of detoxifying enzymes downstream AhR signaling and restricting proinflammatory cytokines. Our data also suggest a novel, noncanonical role of TET1 in regulating chromatin accessibility and CTCF looping to regulate gene expression, in addition to DNA methylation and histone modification, in human bronchial epi- thelial cells. Importantly, we found that TET1 regulates the expression of RNA m6A RWEs in HBECs and mouse lungs, through both canonical and non-canonical roles, resulting in changes in global RNA m6A. Collectively, we hypothesize that TET1 mediates interactions between multiple epigenomic mechanisms and RNA m6A to re- strict PM-induced lung inflammation. To test this hypothesis, we will examine how TET1 regulates m6A RWEs in airway epithelial cells by analyzing 5mC/5hmC, histone modifications, chromatin accessibility, and CTCF-medi- ated looping in response to PM exposure in Aim 1. In Aim 2, we will identify genome-wide RNA m6A changes following PM exposure and TET1 loss and determine the impact of these changes on mRNA stability and protein translation of target genes, especially those contributing to lung inflammation. In Aim 3, we will identify genomic locations with both RNA m6A and TET1-regulated epigenomic features, investigate interactions between TET1 and m6A readers at these locations, and evaluate the impact of PM exposures on these interactions. Leveraging a highly collaborative research team with complementary expertise, unique PM samples and resources, and state-of-the-art technologies, the proposed research is expected to provide novel mechanistic insights into PM- induced pulmonary toxicity and disease, potentially leading to targeted interventional strategies.