Forschung & Innovation
Publikationen
The Respiratory Burst of Human Granulocytes Is Mostly Independent of Potassium
PMU Autor*innen
Iryna Mahorivska, Gustavo Chaves, Martin Jakab, Katharina Helm, Boris Musset
Alle Autor*innen
Iryna Mahorivska, Martin Geltinger, Gustavo Chaves, Sebastian Lobmann, Martin Jakab, Katharina Helm, Boris Musset
Fachzeitschrift
Biomolecules
Kurzfassung
Reactive oxygen species (ROS) are among the most effective tools of the innate immune response against pathogenic microbes. The respiratory burst (RB) of polymorphonuclear leukocytes (PMNs) generates an electron current that reduces molecular oxygen to superoxide. Superoxide reacts to form hydrogen peroxide as a precursor to the highly bactericidal hypochlorous acid. Here, we investigated whether alterations in extracellular potassium concentration impact H 2O 2 production. Such changes may occur, for example, during massive cell death due to necrosis or due to trauma injuries when potassium diffuses out of the cells. We recorded H 2O 2 release over a 2 h period of RB under varying potassium concentrations. Except for 100 mM potassium chloride, which increased the time delay before detectable H 2O 2 production, none of the potassium concentrations had a substantial effect on RB. We further examined whether this effect depended on the specific monovalent ion species. When sodium or methanesulfonate was used instead of potassium or chloride, respectively, no changes in H 2O 2 production were observed. Cell volume measurements under different potassium concentrations showed that only 100 mM potassium chloride significantly shrank the cells. We propose that hypertonic stress is crucial for delaying RB in human granulocytes, whereas the RB itself is independent of the tested ionic species. Additionally, the conducted hypertonic stress experiments revealed an unexpected time-dependence during the course of the RB, showing that the first 6 min were almost inert to hyperosmotic stress.
Keywords
Humans, Potassium/metabolism, Reactive Oxygen Species/metabolism, Respiratory Burst/drug effects, Hydrogen Peroxide/metabolism, Granulocytes/metabolism, Superoxides/metabolism, Neutrophils/metabolism