Proteomic Tools to Characterize Non-Thermal Plasma Effects in Eukaryotic Cells

Abstract

Plasma medicine is an exciting new scientific field due to recent developments in nonthermal physical plasmas operating at atmospheric pressure. In the present study, the effect of an argon-operated plasma jet (kINPen) using either humidified or dry argon as the working gas was investigated on human keratinocytes with respect to changes in the cellular protein expression pattern. The possibility of characterizing the plasma source by its effects on the cell model was tested. After successfully establishing the gel-free proteomics approach using liquid chromatography–high-resolution mass spectrometry, a data set of 3,818 different human proteins from all cellular compartments and protein classes was analyzed. Overall, 10% of proteins were regulated by the plasma treatment, indicating a strong effect of the plasma on the human cell. While there is only weak evidence for direct protein modification, plasma does trigger the active translation of stress-responding proteins. Among the most regulated proteins, cytoskeletal components (keratins), chaperones (heat shock proteins), and proteins involved in oxygen turnover (oxidoreductases, NQO1) were found. Therefore, the presence of reactive oxygen species as well as an organized cellular response are indicated, emphasizing the need for further research in medical applications. Additionally, our approach enables the differentiation between the two selected plasma parameters, allowing its further use to identify key players both in plasma-treated liquids and cellular response. This study and the methodology described herein can be used as a basis to further address the underlying mechanisms of plasma–cell interactions. The data obtained will facilitate fundamental understanding on cellular responses after plasma stimulation.