Cold atmospheric pressure plasma (plasma) is an ionised gas that has shown great im-portance in different medical applications, with the most promising results in cancer treatment and wound healing. Even though we know the effects of plasma in medicine and the mechanisms of response after longer incubation time, there is a lack of research in short term effects on mammalian cells. Plasma induces the formation of reactive oxygen and nitrogen species, which are responsible for oxidative stress. The first cell response to stress is formation of stress granules. They are membraneless organelles that save energy and only allow for essential processes required for cell survival to take place. Protein translation stops when stress granules are formed, and messenger ribonucleic acids, translation initiation factors, proteins and other components are stored in newly established organelles until stress subsides. When the stress is alleviated, stress granules start to disassemble and free components are again available for translation or enter clearance with autophagy. With the help of stable cell line FlpIn SH-SY5Y harboring the gene for stress granule core protein G3BP1 fused to red fluorescent protein mScarletI, we monitored the formation and dynamics of stress granules after argon plasma jet treatment. We showed that plasma induces stress granule formation in flow/time dependant manner and that the cell response resem-bles the one caused by oxidative stress. We discovered that plasma induces stress granule formation via eukaryotic initiation factor 2α (eIF2α)-dependent pathway with the use of ISRIB, a selective inhibitor of eIF2α-dependent pathway. The percentage of cells forming stress granules after ISRIB exposure is reduced by almost seven-fold in comparison to control. We present the first results that describe immediate response of mammalian cells to plasma treatment. With this knowledge we might improve therapies involving plasma treatment and provide better understanding of possible side effects.
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