The circRNA-Sphingolipid Axis: A Novel Driver of Alcohol-Associated Liver Disease. - PROJECT SUMMARY/ABSTRACT Alcohol associated liver disease (ALD) is a prevalent and debilitating liver disease worldwide that contributes to cirrhosis and liver failure, and there are currently no drugs or treatment for ALD. Sphingolipids have been implicated in the pathogenesis of metabolic diseases, particularly through their roles in inflammation. However, the role of sphingolipid metabolism in ALD remains poorly understood. Preliminary data indicates that the glycosphingolipid synthesis pathway, along with key metabolic genes such as UDP Glucose Ceramide Glucosyltransferase (UGCG) and UDP glycosyltransferase 8 (UGT8) are significantly upregulated in patients with ALD. Despite these findings, the precise role of glycosphingolipids in alcohol-induced liver injury and the mechanisms driving ALD progression have not been characterized. Circular RNAs (circRNA), a class of non- coding RNAs characterized by their covalently closed structure, have been shown to regulate gene expression by interacting with microRNAs (miRNAs) and RNA binding proteins (RBPs). Preliminary data identified that circUGCG, a circRNA derived from UGCG, was significantly upregulated in ALD patients, suggesting a novel link between the glycosphingolipid pathway and circular RNAs in ALD pathogenesis. The overall objective of this project is to elucidate the roles and mechanisms in which circUGCG contribute to ALD, and the ultimate goal is to identify targets for diagnostic tools and therapeutic development. Based on the hypothesis that elevated expression of circUGCG promotes ALD pathogenesis by disrupting sphingolipid homeostasis and exacerbating hepatocellular injury and inflammation, the following aims are proposed: Aim 1. Examine the role of circUGCG in alcohol-induced hepatic injury and inflammation using targeted genetic approaches in in vitro and ex vivo models. Using RNA biology experiments, organoids, and RNA sequencing, the proposed project will define the contribution of circUGCG to these pathological processes. Aim 2. Identify the cellular/molecular mechanisms and pathways by which circUGCG induces sphingolipid dysregulation and liver injury in ALD. The proposed project will investigate the potential mechanisms by which the dysregulated circRNA-sphingolipid axis contributes to the progression of ALD via circRNA-miRNA-mRNA networks and circRNA-RBP interactions using sphingolipidomics, ALD mouse models, spatial transcriptomics, and RNAscope. Accomplishing these aims could provide valuable information for the development of new therapeutics and biomarkers. Further, this application includes an excellent research environment for the proposed work, including a collaborative mentorship team of physician scientists and scientists, access to cutting edge technologies and resources, and multiple well-funded and supportive Institutes and Centers that encourage translational research. The candidate will resultantly learn new scientific skills, gain knowledge and skills in basic science, clinical trials, and translational research, and participate in professional development. This training is critical towards the candidate’s goals of becoming an independent physician scientist, performing translational research, and treating patients as a gastroenterologist.
