title: Intracellular reactions in single human granulocytes upon phorbol myristate acetate activation using confocal Raman microspectroscopy.
abstract: We have obtained new evidence for the occurrence of intracellular NADPH-oxidase activity in neutrophilic and eosinophilic granulocytes upon stimulation with phorbol myristate acetate (PMA). PMA activation leads to a partial translocation of cytochrome b(558) from the membranes of the specific granules to the plasma membrane. It was suggested that NADPH-oxidase activity only takes place in the plasma membrane, leading to an extracellular release of oxygen metabolites because cellular self-destruction can be avoided in this way. The effects of PMA activation were indirectly studied in recent experiments employing scavengers of extracellular superoxide anion and hydrogen peroxide, and support for intracellular NADPH-oxidase activity was obtained. In this paper we use Raman microspectroscopy as a direct method to study intracellular molecular reactions that result from cellular triggering by PMA. The molecular specificity of this microscopic method enables us to show that intracellular reduction of both myeloperoxidase (MPO) and cytochrome b(558) occurs in neutrophilic granulocytes. Control measurements with cytochrome b(558)-deficient neutrophilic granulocytes did not show a reduction of intracellular MPO. This is direct support for the occurrence of intracellular NADPH-oxidase activity in organelles that must be in close contact with the azurophilic granules that contain MPO. Furthermore, a comparison was made with chemical reactions occurring in eosinophilic granulocytes after activation with PMA. Moreover, in these cells an intracellular reduction of eosinophil peroxidase was observed.
authors.affiliation: University of Twente, Institute for Biomedical Technology, Department of Applied Physics, Applied Optics Group (TOP), 7500 AE Enschede, the Netherlands.
authors.forename: N M
authors.initials: NM
authors.lastname: Sijtsema
authors.forename: A G
authors.initials: AG
authors.lastname: Tibbe
authors.forename: I G
authors.initials: IG
authors.lastname: Segers-Nolten
authors.forename: A J
authors.initials: AJ
authors.lastname: Verhoeven
authors.forename: R S
authors.initials: RS
authors.lastname: Weening
authors.forename: J
authors.initials: J
authors.lastname: Greve
authors.forename: C
authors.initials: C
authors.lastname: Otto
mesh_terms: D055592:Biophysical Phenomena; D001703:Biophysics; D003573:Cytochrome b Group / Q000378:metabolism; D006098:Granulocytes / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D066298:In Vitro Techniques; D007424:Intracellular Fluid / Q000378:metabolism; D019255:NADPH Oxidases / Q000378:metabolism; D009504:Neutrophils / Q000187:drug effects / Q000378:metabolism; D010084:Oxidation-Reduction; D009195:Peroxidase / Q000378:metabolism; D013059:Spectrum Analysis, Raman; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
chemical_list: D003573:Cytochrome b Group; C036888:cytochrome b558; D009195:Peroxidase; D019255:NADPH Oxidases; D013755:Tetradecanoylphorbol Acetate