PROJECT SUMMARY/ABSTRACT: The diabetic wound healing impairment represents a major clinicalproblem resulting in prolonged hospitalizations and significant healthcare expenditures. Two-thirds of non-traumatic amputations are preceded by a diabetic wound. The impaired healing of diabetic wounds has beenshown to be multifactorial however increasing evidence suggests that persistent inflammation contributes tothe pathogenesis of diabetic wounds through persistent activation of inflammatory pathways and increasedoxidative stress. We have shown that diabetic wounds have increased expression of the proinflammatorycytokines IL-6 and IL-8 and decreased expression of the anti-inflammatory microRNA-146a which inhibitsNFkB activation and downstream IL-6 and IL-8 gene expression. In normal wound healing macrophages areinitially polarized to the proinflammatory M1 phenotype and then transition to the M2 phenotype which isassociated with resolution of inflammation and wound closure. Chronic inflammation and the associated ROSpromote persistent proinflammatory M1 macrophage polarization and a failure to transition to the M2phenotype which has been implicated in the development of chronic diabetic wounds. We have designednovel cerium oxide nanoparticles (CNPs) that possess ROS scavenging properties and have conjugated themwith a miR-146a mimetic to synergistically target both proinflammatory signaling and ROS. In compellingpreliminary data we have found that one-time treatment of murine diabetic wounds with our novel miR-146aconjugated CNPs (CNP-miR146a) can improve diabetic wound healing similar to that of non-diabetic woundsat 7 days and this is associated with decreased inflammation and decreased expression of NOX2. Inadditional preliminary data we have shown that CNP-miR146a can also improve wound healing in astreptozotocin porcine diabetes model. The objective of this work is to determine the mechanisms by whichCNP-miR146a corrects the diabetic wound healing impairment and validate this correction and toxicity in apreclinical porcine model. We hypothesize that CNP-miR146a will reduce inflammation and oxidative stressthus driving macrophage transition from a proinflammatory (M1) to an anti-inflammatory (M2) phenotype andallow for resolution of the chronic inflammatory response and result in enhanced healing.Specific aim 1: To test whether CNP-miR146a corrects the diabetic wound healing impairment bydecreasing inflammation and oxidative stress.Specific aim 2: To test whether decreased inflammation and oxidative stress with CNP-miR146atreatment improves healing by decreased proinflammatory (M1) and increased anti-inflammatory/resolving (M2) macrophage polarization.Specific aim 3: To validate that microRNA-146a conjugated CNPs correct the diabetic wound healingimpairment and is non-toxic in a preclinical porcine model.