Abstract 13004: Blockade of Endothelial to Mesenchymal Transition (EndMT) by an AP-1 Inhibitor Attenuates Atherosclerosis in Diabetes

Abstract

Background: Atherosclerotic cardiovascular disease is the leading cause of death in individuals with diabetes. Endothelial to mesenchymal transition (EndMT) is characterized by endothelial transformation to a mesenchymal like cellular state. EndMT-mediated endothelial cell dysfunction is known to be involved in cardiovascular complications of diabetes including atherosclerosis. Gene expression changes occur when endothelial cells transition to mesenchymal cells. These transcriptomic changes are regulated by multiple factors including transcription factors (TFs). Although, previous studies have implicated the role of EndMT in atherosclerosis, the role of AP-1 TF complex in EndMT in diabetes induced atherosclerosis is not known. Methods: Single cell transcriptomic (SCT) analysis of diabetic aorta in atheroprone Apoe -/- mice was performed using 10X Genomics platform. In vitro model mimicking diabetes-induced EndMT was established in human aortic endothelial cells (HAECs) using high glucose (25mM) and TNF- α ± a small molecular inhibitor of AP-1, T-5224. RNA and ChIP (chromatin Immunoprecipitation) sequencing was performed. Moreover, Apoe -/- mice made diabetic with streptozotocin, were treated with T-5224 (30 mg/kg daily for 5 weeks) in a 10-week intervention study. Results: SCT analysis of aorta identified increased expression of AP-1 members cFOS and Junb in diabetic endothelial cells in Apoe -/- mice. These genes were also upregulated in the HAECs-based in vitro EndMT model. Interestingly, AP-1 inhibition by T-5224 attenuated EndMT . RNA and ChIP sequencing identified several AP-1 target genes including Col1A2, Col4A1, TGFB, THBD, INSR, PIK3R3 (FDR <0.05, Log2 fold change (2x)) that were common to many enriched pathways including “leukocyte trans-endothelial migration” and “AGE-RAGE signaling pathways in diabetic complications” directly relevant to EndMT in diabetes. Importantly, T-5224 treatment blocked EndMT resulting in reduced atherosclerosis in diabetic Apoe -/- mice. Conclusion: This study identified the AP-1 inhibition with T-5224 as a novel treatment for the first time for the diabetes induced EndMT and atherosclerosis.