PROJECT SUMMARY Delayed or impaired wound healing is a serious complication of diabetes, often leading to lower limb ampu- tations. By 2050, 1 in 3 Americans will develop diabetes, and up to 34% of diabetic patients will develop a diabetic foot ulcer (DFU) in their lifetime. Standard of care for DFUs includes debridement, infection control, maintaining a moist wound environment, and pressure offloading. Despite these interventions, a large number of DFUs fail to heal and are associated with a cost that exceeds $31 billion annually. Chronic inflammation and increased oxidative stress have been implicated in the pathogenesis of the diabetic wound healing impairment. We have designed and tested a new therapeutic that synergistically targets both inflammation and oxidative stress using novel cerium oxide nanoparticles (CNP), which possess reactive oxygen species (ROS) scavenging properties, conjugated with an anti-inflammatory microRNA mimic (miR146a) that is deficient in diabetic wounds and inhibits the activation of NF-kappa-B-induced pro-inflammatory response. Importantly, our novel, patented conjugate CNP-miR146a efficiently delivers miR146a into the wound and reduces inflammation and ROS. Using a CNP-miR146a specifically formulated for intradermal injection (CTX-001), we demonstrated that a one-time administration of CTX-001 to full-thickness wounds fully corrected the wound healing impairment in diabetic mice and elicited a significant 25% improvement in wounds in diabetic pigs. Repeated weekly admin- istration corrected the diabetic wound healing impairment in diabetic pigs, similar to healing in non-diabetic wounds. We have subsequently developed CNP-mi146a as a hydroxymethylcellulose gel formulation (CTX-004), which can be used for topical administration as a more attractive alternative based on market research. The main objective of this Phase I application by Ceria Therapeutics is to optimize the gel formulation of CTX-004 (Aim 1.1) and demonstrate its efficacy in the treatment of diabetic mouse wounds by establishing the minimum effective dose required to improve the time to and quality of wound healing (Aim 1.2). In Aim 2 we will perform a preclinical study to compare the efficacy of the optimal formulation and dose of CTX-004 with the only FDA approved gel (Regranex®) for treating diabetic foot ulcers. Aim 3 will assess if there is any effect of bacterial load on the efficacy of CTX-004 in the healing of diabetic mouse wounds. Successful completion of the efforts de- scribed in this proposal will position Ceria to advance CTX-004 to IND-enabling studies, file an IND application, and initiate a First-in-Human clinical trial.