Nitrosylation vs. oxidation – How to modulate cold physical plasmas for biological applications

RESEARCH ARTICLE Nitrosylation vs. oxidation – How to modulate cold physical plasmas for biological applications Jan-Wilm Lackmann ID1☯*, Giuliana Bruno1☯, Helena Jablonowski1, Friederike Kogelheide2, Björn Offerhaus2, Julian Held3, Volker Schulz-von der Gathen3, Katharina Stapelmann ID2,4, Thomas von Woedtke1, Kristian Wende1* a1111111111 a1111111111 a1111111111 a1111111111 a1111111111 1 ZIK plasmatis at Leibniz Institute for Plasma Science and Technology (INP Greifswald e.V.), Greifswald, Germany, 2 Institute for Electrical Engineering and Plasma Technology, Ruhr University Bochum, Bochum, Germany, 3 Experimental Physics II, Ruhr University Bochum, Bochum, Germany, 4 Plasma for Life Sciences, Department of Nuclear Engineering, North Carolina State University, Raleigh, North Carolina, United States of America ☯ These authors contributed equally to this work. * (JWL); (KW) Abstract OPEN ACCESS Citation: Lackmann J-W, Bruno G, Jablonowski H, Kogelheide F, Offerhaus B, Held J, et al. (2019) Nitrosylation vs. oxidation – How to modulate cold physical plasmas for biological applications. PLoS ONE 14(5): e0216606. https://doi.org/10.1371/ journal.pone.0216606 Editor: Mohammed Yousfi, Universite Toulouse III Paul Sabatier, FRANCE Received: November 30, 2018 Accepted: April 24, 2019 Published: May 8, 2019 Copyright: © 2019 Lackmann et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability Statement: The data underlying this study have been deposited to OSF and are freely accessible via https://osf.io/w6tdq/?view_ only=576dfc8057ae42039f0011ca1224a054. Funding: K. W. acknowledges funding by the German Federal Ministry of Education and Research (BMBF) - Grant No. 03Z22DN12. J.H. and V. SvdG acknowledge funding by the German Research Foundation by the PlaCID project (DFG, PAK816) and the SFB1316. The funders had no role in study design, data collection and analysis, Thiol moieties are major targets for cold plasma-derived nitrogen and oxygen species, making CAPs convenient tools to modulate redox-signaling pathways in cells and tissues. The underlying biochemical pathways are currently under investigation but especially the role of CAP derived RNS is barely understood. Their potential role in protein thiol nitrosylation would be relevant in inflammatory processes such as wound healing and improving their specific production by CAP would allow for enhanced treatment options beyond the current application. The impact of a modified kINPen 09 argon plasma jet with nitrogen shielding on cysteine as a thiol-carrying model substance was investigated by FTIR spectroscopy and high-resolution mass spectrometry. The deposition of short-lived radical species was measured by electron paramagnetic resonance spectroscopy, long-lived species were quantified by ion chromatography (NO2-, NO3-) and xylenol orange assay (H2O2). Product profiles were compared to samples treated with the so-called COST jet, being introduced by a European COST initiative as a reference device, using both reference conditions as well as conditions adjusted to kINPen gas mixtures. While thiol oxidation was dominant under all tested conditions, an Ar + N2/O2 gas compositions combined with a nitrogen curtain fostered nitric oxide deposition and the desired generation of S-nitrosocysteine. Interestingly, the COSTjet revealed significant differences in its chemical properties in comparison to the kINPen by showing a more stable production of RNS with different gas admixtures, indicating a different •NO production pathway. Taken together, results indicate various chemical properties of kINPen and COST-jet as well as highlight the potential of plasma tuning not only by gas admixtures alone but by adjusting the surrounding atmosphere as well. PLOS ONE | https://doi.org/10.1371/journal.pone.0216606 May 8, 2019 1 / 25 S-nitrosylation of cysteine by plasma jets decision to publish, or preparation of the manuscript. Competing interests: The authors have declared that no competing interests exist. Introduction Cold atmospheric plasmas (CAP) are used in a wide variety of fields. In particular, the interest in medical applications has increased in recent years. Multiple scientific studies and case studies confirm CAPs effectiveness for therapeutic purposes, such as wound healing and skin regeneration but also cancer treatment [1–3]. Plasma sources have different designs and discharge concepts, and consequently vary in gas composition and chemical properties of the produced plasma [4–6]. In particular, various reactive oxygen and nitrogen species (RONS) are deposited in treated liquids or in the cellular environment. Production of these species in the gas phase and interaction at the gas-liquid interface vary according to the chosen plasma source and related parameters, leading to a distinct deposition of RONS in the liquid bulk [7– 9]. In biological systems, these plasma-generated species modulate redox-signaling processes, ultimately leading to functional consequences [10]. Among these, an increased expression of anti-oxidant proteins such as members of the glutathione metabolism, changes in cell migration rate and cell viability have been observed in cell [11] and animal models [12]. Given the fact, that most of the plasma-derived species are short lived, the question arises which biochemical mechanisms are relevant to relay the chemical information from the plasma to the cell. Several studies focus on the deposition and production of RONS in liquid media for biomedical applications. Chauvin et al. investigated several media after treatment with a plasma jet and demonstrated efficient deposition of both long (hydrogen peroxide, nitrite, and nitrate) and short-living (superoxide, hydroxyl radicals) species [13]. Furthermore, a possible pathway is the (covalent) modification of biomolecules, e.g. at the amino acid cysteine. Its thiol group can bear oxidation states from -2 to +6, forming a number of chemotypes with biological importance [14]. An initial oxidation product is cysteine sulfenic acid (RSOH). RSOH rapidly reacts with other thiols to form disulfides (RSSR), such as cystine. Strong oxidizing agents can lead to a progressive oxidation of cysteine to its sulfinic (RSO2H) and/or sulfonic acids (RSO3H) [14, 15]. In mammalian cells, this reactivity is harnessed in redox signaling processes were an initial step in signal transduction is the controlled oxidation of cysteines, e.g. in peroxiredoxins, that subsequently lead to changes in protein conformation, trafficking, or downstream chemical processes (“thiol switches”) [16–18]. Other biologically active modifications are S-glutathionylation and S-nitrosylation, modulating the cysteine residue activity and protein function [19, 20]. Comparable covalent modifications (...truncated)