title: Stimulation of cellular free Ca2+ elevation and inhibition of store-operated Ca2+ entry by kazinol B in neutrophils.
abstract: Kazinol B, a natural isoprenylated flavan, stimulated the [Ca(2+)](i) elevation in the presence or absence of Ca(2+) in the medium. Treatment with chymotrypsin or phorbol 12-myristate 13-acetate to shedding of L: -selectin had no effect on subsequent kazinol B-induced Ca(2+) response. Upon initial cyclopiazonic acid (CPA) treatment in the absence of external Ca(2+), the subsequent [Ca(2+)](i) rise followed by challenge with kazinol B was greatly diminished. The ryanodine receptor blockers, 8-bromo-cyclic ADP-ribose and ruthenium red did not affect kazinol B-evoked Ca(2+) release from internal stores. However, the inhibitors of sphingosine kinase, dimethylsphingosine, but not dihydrosphingosine, inhibited kazinol B-induced Ca(2+) release. Kazinol B-induced [Ca(2+)](i) rise was not affected by two nitric oxidase inhibitors, N-(3-aminomethyl)benzylacetamidine (1400W) and 7-nitroindazole, cytochalasin B and Na(+)-deprivation. This response was slightly attenuated by 2-aminoethyldiphenyl borate (2-APB), a D: -myo-inositol 1,4,5-trisphosphate (IP(3)) receptor blocker, and by genistein, a general tyrosine kinase inhibitor. However, the Ca(2+) response was greatly diminished by two actin filament reorganizers, calyculin A and jasplakinolide, 2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one (LY 294002), an inhibitor of phosphoinositide 3-kinase, N-(3-aminomethyl)benzylacetamidine (SB 203580), the p38 mitogen-activated protein kinase inhibitor, 1-[6-[17beta-3-methoxyestra-1,3,5(10)-trien-17-yl]amino]hexyl]-1H-pyrrole-2,5-dione (U-73122), the inhibitor of phospholipase C-coupled processes, and by 0.3 mM La(3+) or Ni(2+). Kazinol B did not evoke any appreciable Ba(2+) and Sr(2+) entry into cells. The Ca(2+) entry blockers, 1-[beta-[3-(4-methoxyphenyl)propoxy]-4-methoxyphenethyl]-1H-imidazole (SKF-96365), but not cis-N-(2-phenylcyclopentyl)azacyclotridec-1-en-2-amine (MDL-12,330A), inhibited a kazinol B-induced [Ca(2+)](i) rise. Kazinol B had no effect on the pharmacologically isolated plasma membrane Ca(2+)-ATPase activity. In a Ca(2+)-free medium, kazinol B inhibited the subsequent Ca(2+) addition, resulting in robust entry in CPA- and formyl peptide-activated cells. Kazinol B produced a concentration-dependent reduction in the mitochondrial membrane potential. These results indicate that kazinol B stimulates Ca(2+) release from internal Ca(2+) store, probably through the sphingosine 1-phosphate and IP(3) signaling, and activates external Ca(2+) influx mainly through a non-store-operated Ca(2+) entry (non-SOCE) pathway. Inhibition of SOCE by kazinol B is probably attributable to a break in the Ca(2+) driven force of mitochondria.
authors.affiliation: Department of Education and Research, Taichung Veterans General Hospital, Taichung, Taiwan, Republic of China. w1994@vghtc.gov.tw
authors.forename: Jih-Pyang
authors.initials: JP
authors.lastname: Wang
authors.forename: Mei-Feng
authors.initials: MF
authors.lastname: Hsu
authors.forename: Horng-Huey
authors.initials: HH
authors.lastname: Ko
authors.forename: Chun-Nan
authors.initials: CN
authors.lastname: Lin
mesh_terms: D000818:Animals; D002118:Calcium / Q000037:antagonists & inhibitors* / Q000378:metabolism* / Q000502:physiology; D020013:Calcium Signaling / Q000187:drug effects / Q000502:physiology; D002462:Cell Membrane / Q000187:drug effects* / Q000502:physiology; D002474:Cell-Free System / Q000378:metabolism / Q000502:physiology; D005419:Flavonoids / Q000494:pharmacology*; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D009504:Neutrophils / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D005419:Flavonoids; C117415:kazinol B; D002118:Calcium