Th17 cells of type 2 diabetic patients present an aberrant fatty acid metabolic pathway

Abstract

Abstract Approximately 90% of the 537 million diabetic adults worldwide are living with type 2 diabetes (T2D). T2D is a metabolic disorder characterized by elevated blood glucose, which develops when a person is resistant to or cannot make enough insulin. Chronic systemic inflammation is a key contributing factor in the onset of insulin resistance and T2D. This inflammation in T2D patients stems from T-helper 17 (Th17) cells, likely due to defects in fatty acid metabolic pathways driving Th17 inflammation in T2D. While the importance of lipid metabolism has been shown in in vitro differentiated Th17 cells, the metabolism of endogenous Th17 cells in health or T2D has not been characterized due to their low abundance in vivo. We overcame this obstacle and established the relationship between defects in fatty acid metabolism and endogenous Th17 effector function with a novel Th17 cell enrichment assay. We captured CD4+ T cells with a hydrogel particle and magnetically purified them based on secretion of IL-17A/17F/21, allowing for us to perform scRNAseq on endogenous, activated Th17 cells. We then utilized an algorithm named Compass-powered by scRNAseq data and flux balance analysis, to characterize the cellular metabolic state of our captured Th17 cells. By overlaying scRNAseq data from endogenous Th17 cells of diabetic and control patients with gene ontology resources and applying in-silico modeling of metabolic pathways, we identified key lipid pathways driving Th17 inflammation in T2D and conducted the first study ever to be done on endogenous Th17 cells of healthy and T2D patients. This novel approach, and the data that ensued from it, with functional validation will illuminate inflammatory markers to target for creation of an immunotherapy for T2D. Supported by grants from NIH (1DP2AI171121-01)