The blockade of cyclopiazonic acid-induced store-operated Ca2+ entry pathway by YC-1 in neutrophils.
In the presence of external Ca2+, pretreatment of neutrophils with 3-(5'-hydroxymethyl-2'-furyl)-1-benzyl indazole (YC-1) inhibited the cyclopiazonic acid (CPA)-induced [Ca2+](i) elevation in a concentration- but not a time-dependent manner, while YC-1 had no effect on the Ca2+ signals in a Ca2+-free medium. YC-1 failed to inhibit ATP- and interleukin-8 (IL-8)-induced [Ca2+](i) changes. Addition of YC-1 after cell activation strongly inhibited the CPA-induced [Ca2+](i) changes. In a classical Ca2+ readdition protocol, a similar extent inhibition of Ca2+ spike by YC-1 introduced either prior to or after CPA stimulation was obtained. In rat neutrophils, mRNA for endothelial differentiation gene (edg)1, edg5, edg6 and edg8, the putative targets for sphingosine 1-phosphate (S1P), could be detected. However, S1P was found to have little effect on Ca(2+) signals. YC-1 did not inhibit but enhanced the sphingosine-induced [Ca2+](i) changes. Inhibition by YC-1 of CPA-induced [Ca2+](i) changes was not prevented by 7-nitroindazole and N-(3-aminomethyl)benzylacetamidine (1400W), two nitric oxide synthase (NOS) inhibitors, by aristolochic acid, a phospholipase A(2) inhibitor, or by suspension in a Na(+)-deprived medium. YC-1 did not affect the mitochondrial membrane potential. Moreover, YC-1 did not alter [Ca2+](i) changes in response to ionomycin after CPA and formyl-Met-Leu-Phe (fMLP) stimulation in a Ca2+-free medium. YC-1 had no effect on the basal [Ca2+](i) level, the pharmacologically isolated plasma membrane Ca2+-ATPase activity, and Ba2+ entry into CPA-activated cells. YC-1 alone resulted in the accumulation of actin filaments in neutrophils, while significantly reduced the intensity of actin filament staining in the subsequent activation with CPA. These results indicate that YC-1 inhibited CPA-activated store-operated Ca2+ entry (SOCE) probably through the direct blockade of channel activation and/or the disruption of the integrity of the actin cytoskeleton necessary for supporting Ca2+ entry pathway in neutrophils.
Department of Education and Research, Taichung Veterans General Hospital, Taichung 407, Taiwan, Republic of China. w1994@vghtc.gov.tw
Jih-Pyang
JP
Wang
Yu-San
YS
Chen
Chi-Ren
CR
Tsai
Li-Jiau
LJ
Huang
Sheng-Chu
SC
Kuo
D000199:Actins / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000494:pharmacology; D000578:Amidines / Q000494:pharmacology; D000818:Animals; D034341:Aristolochic Acids / Q000494:pharmacology; D001464:Barium / Q000378:metabolism; D001596:Benzylamines / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D020013:Calcium Signaling; D000252:Calcium-Transporting ATPases / Q000378:metabolism; D004347:Drug Interactions; D004791:Enzyme Inhibitors / Q000494:pharmacology; D007191:Indazoles / Q000494:pharmacology*; D007211:Indoles / Q000494:pharmacology*; D016209:Interleukin-8 / Q000494:pharmacology; D008564:Membrane Potentials / Q000187:drug effects; D008928:Mitochondria / Q000187:drug effects / Q000502:physiology; D009504:Neutrophils / Q000187:drug effects* / Q000378:metabolism; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D049349:Receptors, Lysosphingolipid / Q000378:metabolism; D012964:Sodium / Q000378:metabolism; D013110:Sphingosine / Q000494:pharmacology
D000199:Actins; D000578:Amidines; D034341:Aristolochic Acids; D001596:Benzylamines; D004791:Enzyme Inhibitors; D007191:Indazoles; D007211:Indoles; D016209:Interleukin-8; C104820:N-(3-(aminomethyl)benzyl)acetamidine; D010975:Platelet Aggregation Inhibitors; D049349:Receptors, Lysosphingolipid; C090937:3-(5'-hydroxymethyl-2'-furyl)-1-benzylindazole; D001464:Barium; D000255:Adenosine Triphosphate; C000228:aristolochic acid I; D012964:Sodium; D000252:Calcium-Transporting ATPases; D013110:Sphingosine; D002118:Calcium; C080122:7-nitroindazole; C000543:cyclopiazonic acid