Inflammation is implicated in a wide range of disorders and thought to be involved in most leading causes of death today in the United States with high associated costs. New insights into better understanding its etiology, detection and prevention are thus of major importance in health care. This has been achieved in part through the recent discovery of proinflammatory DAMPs, including mitochondrial DNA (mtDNA). However, little is known about the proinflammatory effects of the other major mitochondrial nucleic acid, mtRNA. Here, we propose to fill this gap by extending our recent mtRNA studies and assessing therapeutic targets. These studies are a major extension of a previously small literature on mtRNA immunostimulation, and provide new insights into the role of native and oxidized mtRNA in inflammation as a result of their inappropriate release to the cytoplasm and extracellular milieu including blood. Specifically, we propose to test the hypothesis that both native and oxidized mtRNAs are important inflammatory mediators with diagnostic and treatment potential. Here, we will characterize the mechanistic basis underlying the proinflammatory activity of mitochondrial RNA (mtRNA); determine the mechanistic effect of oxidation on mtRNA immunostimulation; and assess the immunostimulatory activity and associated structural forms of mtRNA in human plasma. The overall goal is to better understand the role of both native and oxidized forms of mtRNA in inflammation, and to eventually exploit this information toward the diagnosis and treatment of excessive mtRNA release-related inflammatory pathologies.