Biphasic regulation of polymorphonuclear leukocyte spreading by polyphenolic compounds with pyrogallol moieties.
Green tea polyphenols have been reported to have anti-inflammatory activities, although the molecular mechanisms responsible for this effect remain unclear. In the present study, we examined the effect of green tea extract and a variety of polyphenolic compounds on spreading of peripheral blood polymorphonuclear leukocytes (PMNs) over fibrinogen-coated surfaces. Green tea extract exerted a biphasic effect on PMN spreading; it induced or suppressed spreading at low and high concentrations, respectively. We also found that pyrogallol-bearing compounds have spreading induction activity. Among the compounds tested, tannic acid (TA) had the strongest activity; the concentrations required for induction of maximal spreading were 2 microM for TA, 200 microM for (-)-epigallocatechin gallate, and 2000 microM for the other active compounds. Furthermore, TA was the only compound showing a biphasic effect similar to that of green tea extract; TA at 20 or 200 microM suppressed spreading. The spreading-stimulatory signal was still latent during PMN exposure to TA at concentrations that inhibited spreading, because the pre-exposed PMNs underwent spreading when plated after removal of free TA by centrifugation. The spreading-inhibitory effect of TA at high concentrations overcame the induction of spreading by other stimuli, including phorbol 12-myristate 13-acetate, hydrogen peroxide, denatured fibrinogen surfaces, and naked plastic surfaces. These results suggest that TA as well as green tea extract is bi-functional, having pro-inflammatory and anti-inflammatory effects at low and high concentrations, respectively. Pharmacological use of TA may thus provide new strategies aimed at regulation of PMN spreading for control of inflammation.
Kori
Soichiro
S
Department of Biology, School of Education, Waseda University, Shinjuku-ku, Tokyo, Japan.
Namiki
Hideo
H
Suzuki
Kingo
K
D000818:Animals; D028241:Camellia sinensis; D002392:Catechin / Q000031:analogs & derivatives / Q000494:pharmacology; D002448:Cell Adhesion / Q000187:drug effects / Q000276:immunology; D022081:Cell Surface Extensions / Q000187:drug effects / Q000276:immunology; D002478:Cells, Cultured; D002633:Chemotaxis / Q000187:drug effects / Q000276:immunology; D005340:Fibrinogen / Q000378:metabolism; D009504:Neutrophils / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D010936:Plant Extracts / Q000494:pharmacology*; D011748:Pyrogallol / Q000494:pharmacology; D013552:Swine; D013634:Tannins / Q000494:pharmacology
D010936:Plant Extracts; D013634:Tannins; D011748:Pyrogallol; D002392:Catechin; D005340:Fibrinogen; C045651:epigallocatechin gallate