Redox regulation of leukocyte-derived microparticle release and protein content in response to cold physical plasma-derived oxidants

Recent results in the field of plasma medicine are increasingly motivating the use of cold physical plasma in clinical settings. Especially two major health issues, non-healing wounds and cancers, are in focus of current research. The outcome of both diseases is highly dependent on inflammation, a process that is priory driven by leukocytes. It is known that these cells are able to tune the behavior and inflammatory status of other cells in a paracrine fashion via release of small particles, so-called microparticles or microvesicles. These phospholipid-bilayers carry a cargo of proteins and RNA and release upon fusion their content into target cells. With different immune cell populations physiologically present in healthy as well as diseased tissue, we investigated their small particle release following plasma exposure in vitro. At first, the cytometric analysis technique was established, and analysis of samples revealed a significant modulation of extracellular particle concentrations following exposure to cold plasma. Interestingly, also particle size was affected, indicating alterations in the cellular program of particle generation due to plasma treatment. Proteomic analysis of microparticles using mass spectrometry revealed significant changes in hundreds of proteins regulating, for example, binding, immune processes, transcriptional activity, and redox homeostasis. In the latter, significant modulation of PRX1, PRX2, PRX5, PRX6, TRX, SOD1, SOD2, HSP60, HSP70, and HSP71 protein content of vesicles suggest immune cells to redox-regulate their microenvironment via microparticles in response to plasma. These results further emphasize the potency of cold plasma to not simply damage via oxidation but also to specifically regulate inflammation conceivably of importance in clinical settings.