Project Summary More than 10% of the global adult population currently lives with diabetes mellitus (DM) and are experiencing or at higher risk for various diabetic vasculopathies such as peripheral artery disease (PAD). Despite available treatment, many patients with DM continue to develop diabetic vasculopathy, highlighting the urgent need for more effective therapies. Mounting research has shown that the dysfunction of endothelial cells (ECs), known as endotheliopathy, plays a crucial role in the onset of DM and its vasculopathies. However, there is still a gap in knowledge regarding the epigenetic regulators that drive endotheliopathy in DM and cause persistent vascular damage, and whether these regulators can be targeted for treatment. Synergizing efforts from our funded studies on long non-coding RNA (lncRNA)-regulated EC function (R01HL145170) and diabetic epigenetic memory (R01HL106089), my group has uncovered important roles of non-coding RNAs, including microRNAs and lncRNAs, in endotheliopathy, vascular inflammation, and impaired vascular regeneration in DM and diabetic PAD. Furthermore, we identified chromatin-associated lncRNAs as key mediators of metabolic memory, which may explain the persistent vascular damage observed in patients with DM, even after restoration of normoglycemia. We have also broken new ground to unravel the role of the N6-methyladenosine (m6A)-modified epitranscriptome in DM-induced endotheliopathy and to harness nanoparticles and modified RNA to develop therapeutics that target the dysfunctional EC epigenome. In this R35 application, our overall vision is that elucidating the RNA-mediated epigenetic and epitranscriptional mechanisms underlying DM-associated endotheliopathy in depth will enable us to develop novel therapeutics to ameliorate diabetic vasculopathy. Our proposed studies will bring together expertise in RNA, chromatin, and endothelial biology; gene therapy; and nanomedicine to address this pressing medical issue. We will achieve our goals through three independent yet inter-connected projects to: 1) identify the roles and mechanisms of action of novel lncRNA regulators in driving endotheliopathy and diabetic vasculopathy; 2) determine the role of m6A RNA modification in diabetic endotheliopathy and vasculopathy; and 3) evaluate the efficacy of innovative nanoparticle-mediated epigenetic therapeutics in ameliorating diabetic vasculopathy, with a focus on PAD, a painful disease with limited treatment options. The unique R35 Emerging Investigator Award mechanism will allow me to further my group’s research on RNA-mediated endotheliopathy by testing new hypotheses using innovative technologies. Aligned with the NHLBI mission, our proposed studies will advance our understanding of diabetic vasculopathy and have the potential to facilitate the development of much-needed new therapies for patients with diabetic vasculopathy.