Calcium influx through TRP channels induced by short-lived reactive species in plasma-irradiated solution.

Shota Sasaki,Makoto Kanzaki,Toshiro Kaneko

doi:10.1038/srep25728

Abstract

Non-equilibrium helium atmospheric-pressure plasma (He-APP), which allows for a strong non-equilibrium chemical reaction of O2 and N2 in ambient air, uniquely produces multiple extremely reactive products, such as reactive oxygen species (ROS), in plasma-irradiated solution. We herein show that relatively short-lived unclassified reactive species (i.e., deactivated within approximately 10 min) generated by the He-APP irradiation can trigger physiologically relevant Ca2+ influx through ruthenium red- and SKF 96365-sensitive Ca2+-permeable channel(s), possibly transient receptor potential channel family member(s). Our results provide novel insight into understanding of the interactions between cells and plasmas and the mechanism by which cells detect plasma-induced chemically reactive species, in addition to facilitating development of plasma applications in medicine.

Highlights

Plasma medicine is a rapidly emerging field, and a number of researchers have reported innovative applications of non-equilibrium atmospheric-pressure plasma (APP)[1,2,3,4], including its use in the selective killing of cancer cells[5], in blood coagulation for minimally invasive surgery, in assisting wound healing and tissue regeneration[6], and as a gene transfer tool[7,8,9]
We investigated the interaction between intracellular calcium and chemically reactive species generated in plasma-irradiated solution in 3T3-L1 mouse fibroblasts, with respect to calcium ion influx through transient receptor potential (TRP) channels triggered by the plasma-produced reactive species
How do cells decipher and respond to the wide array of highly complex and interrelated stimuli evoked by APP irradiation, including irradiation with UV rays, reactive oxygen species (ROS), RNS, electric fields, and shock waves1–4? In an attempt to dissect these complex stimuli that directly and/or indirectly affect cellular functions, we focused on the biologically active elements generated in the medium after non-equilibrium Helium atmospheric-pressure plasma (He-APP) irradiation by monitoring intracellular Ca2+ dynamics

Summary

Introduction

Plasma medicine is a rapidly emerging field, and a number of researchers have reported innovative applications of non-equilibrium atmospheric-pressure plasma (APP)[1,2,3,4], including its use in the selective killing of cancer cells[5], in blood coagulation for minimally invasive surgery, in assisting wound healing and tissue regeneration[6], and as a gene transfer tool[7,8,9]. Non-equilibrium APP has a higher electron temperature (~several eV) than gas (ion) temperature[10] This allows for strong non-equilibrium chemical reactions, and computer simulations and experimental results have shown that numerous chemically reactive species are generated in the plasma or in plasma-irradiated solution as a result of these specific reactions[11,12,13,14,15,16,17]. In this system, He gas serves as the source gas, with its flow rate (f) through the dielectric tube regulated by a mass flow controller (MFC), and typically, f = 3 L/min. During and after the addition of plasma-irradiated solution (indirect plasma irradiation), real-time changes in [Ca2+]i are measured using a confocal microscope (FV1000, Olympus) with a fluo-4 AM calcium indicator (F-14201, Invitrogen)

Methods

Results

Conclusion