Ionomycin-induced neutrophil NADPH oxidase activity is selectively inhibited by the serine protease inhibitor diisopropyl fluorophosphate.

• The calcium-specific ionophore ionomycin triggers neutrophils to activate their NADPH oxidase and generate reactive oxygen species. This activation is restricted to intracellular sites and involves the neutrophil granules. Cells that have experienced an ionomycin-induced rise in intracellular calcium will also mobilize their intracellular granules and are primed to subsequent challenge with the chemoattractant formylmethionyl-leucyl-phenylalanine (fMLF), but have lost their ability to become desensitized to the same agonist. We have investigated the involvement of serine proteases in the calcium-induced effector functions using the inhibitor diisopropyl fluorophosphate (DFP). The ionomycin-induced NADPH oxidase activity was abrogated by the protease inhibitor, whereas the activity induced by fMLF was unaffected. The DFP-dependent inhibition was restricted to the NADPH oxidase activity, as all other ionomycin-induced cellular activities were largely unaffected. We thus suggest that a serine protease is of importance for the calcium ionophore-induced signal(s) to reach and activate the dormant NADPH oxidase in the neutrophil granules.

Ämnesord

MEDICIN OCH HÄLSOVETENSKAP  -- Medicinska och farmaceutiska grundvetenskaper -- Immunologi inom det medicinska området (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Basic Medicine -- Immunology in the medical area (hsv//eng)

Nyckelord

Cell-Free System

Humans

Hydrogen Peroxide

pharmacology

Ionomycin

pharmacology

Ionophores

pharmacology

Isoflurophate

pharmacology

Luminescent Measurements

N-Formylmethionine Leucyl-Phenylalanine

pharmacology

NADPH Oxidase

metabolism

Neutrophils

enzymology

metabolism

Oxygen

metabolism

Phagocytosis

Reactive Oxygen Species

Serine

metabolism

Serine Proteinase Inhibitors

pharmacology

Subcellular Fractions

metabolism

Superoxides

Time Factors

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)