Photoactivated inhibition of superoxide generation and protein kinase C activity in neutrophils by blepharismin, a protozoan photodynamically active pigment.
Blepharismin is an endogenous photosensitizing pigment found in the protozoan Blepharisma. This pigment inhibited the generation of superoxide anion (O2-.) in neutrophils not only via a diacylglycerol-induced protein kinase C (PKC)-dependent reaction but also by an arachidonate-induced PKC-independent reaction. The inhibition was light and concentration dependent for both reactions. Light-activated inhibition was strong at wavelengths between 520 and 570 nm but not above 610 nm. PKC activity in neutrophils and from rat brain was inhibited by blepharismin in a light- and concentration-dependent manner. Moreover, arachidonate-activated NADPH oxidase activity in a cell-free system was also inhibited by the pigment in a light- and concentration-dependent manner. These results suggest that blepharismin inhibits NADPH oxidase activation through the non-specific inhibition of various membrane-bound enzymes and that this inhibition may also be correlated with that of PKC.
Watanabe
Y
Y
Department of Medical Biology, Kochi Medical School, Japan.
Edashige
K
K
Kobuchi
H
H
Kato
Y
Y
Matsuoka
T
T
Utsumi
T
T
Yoshioka
T
T
Horton
A A
AA
Utsumi
K
K
D000818:Animals; D002474:Cell-Free System; D056890:Eukaryota / Q000737:chemistry*; D008027:Light; D009247:NADH, NADPH Oxidoreductases / Q000037:antagonists & inhibitors; D019255:NADPH Oxidases; D009504:Neutrophils / Q000187:drug effects* / Q000378:metabolism; D010569:Perylene / Q000031:analogs & derivatives* / Q000302:isolation & purification / Q000494:pharmacology; D010766:Phosphorylation / Q000187:drug effects; D010777:Photochemistry; D010860:Pigments, Biological / Q000302:isolation & purification / Q000494:pharmacology*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors*; D013481:Superoxides / Q000378:metabolism*
D010860:Pigments, Biological; C092293:blepharismin; D013481:Superoxides; D010569:Perylene; D009247:NADH, NADPH Oxidoreductases; D019255:NADPH Oxidases; D011493:Protein Kinase C