Non-thermal plasma treatment changes proteome signature and triggers cell signaling in human cells

Non thermal atmospheric pressure plasmas produce reactive oxygen and nitrogen species (ROS/RNS) which can influence cell physiology and trigger cellular signaling processes. This opens exiting new potentials e.g. in chronic wound care where encouraging results have been obtained in vivo by different research groups. Other data suggest the usability of plasma for anti cancer treatment. The fate of a eukaryotic cell after a challenge is determined by numerous factors. Important roles play the mitogen-activated protein kinases (MAPK). This enzyme group orchestrates cellular behavior upon activation by external stimuli (growth factors, chemicals, radiation), leading either to apoptosis or cell cycle arrest or to survival and differentiation. To gain insight into the processes triggered by non thermal plasma treatment (argon driven kinpen), human keratinocytes and lymphocytes were investigated using different proteomic tools. Protein expression pattern were determined using SILAC and label free high resolution mass spectrometry coupled to liquid chromatography. MAPK signaling pathways were investigated by western blotting technique. An ambivalent behavior of the cells was observed. Protein expression pattern was found to change distinctly 6 h to 8 h after treatment. Differences were less obvious after 3 h and 24 h of incubation. Major changes were identified for proteins involved in metabolism, protein expression, and oxidative stress response. ROS/RNS signaling was observed, together with downstream changes in ROS scavenging enzymes. The activation of different MAPK (p38 MAPK, ERK, JNK) was influenced in a time dependent manner after treatment. Pro survival signaling ERK activation was observed immediately after plasma treatment and decreased afterwards. This indicates a possible activation which was also seen in active protein expression pathways. On the other hand, pro-apoptotic JNK activation increased after 3 to 6 hours after treatment. Hence, depending on the trea- ment time NTP can be used as a stimulus in order to activate cell response either towards survival or cell death. In more complex systems like a tissue, the observed signaling events can activate adjacent cells or cell groups - e.g. to stimulate keratinocyte proliferation or immune response.