Inhibition of phospholipase D activation by CYL-26z in formyl peptide-stimulated neutrophils involves the blockade of RhoA activation.
5-[4-Acridin-9-ylamino]phenyl]-5-methyl-3-methylenedihydrofuran-2-one (CYL-26z) inhibited the formyl-Met-Leu-Phe (fMLP)-stimulated phospholipase D (PLD) activity, which was assessed by the production of phosphatidylethanol (PEt) in the presence of ethanol, in rat neutrophils (IC50 1.2+/-0.2 microM). CYL-26z caused a slight but significant attenuation of the global protein tyrosine phosphorylation stimulated by fMLP only at concentrations of CYL-26z up to 30 microM. CYL-26z blocked the membrane recruitment of protein kinase C-alpha (PKC-alpha) at concentrations of CYL-26z > or =3 microM, but failed to affect the membrane association of PKC-betaI and -betaII. The translocation of RhoA to the membrane was attenuated by CYL-26z (IC50 3.8+/-0.8 microM) in fMLP-stimulated neutrophils, whereas CYL-26z caused no significant inhibition of the membrane recruitment of ADP-ribosylation factor (Arf). CYL-26z inhibited the activation of RhoA and dissociation of the RhoA-Rho guanine nucleotide dissociation inhibitor (GDI) complex in fMLP-stimulated neutrophils (IC50 1.8+/-1.0 microM and 1.8+/-0.9 microM, respectively). In a cell-free system, CYL-26z effectively attenuated the membrane association of RhoA in response to GTPgammaS (IC50 1.3+/-0.5 microM). In contrast, the GTPgammaS-stimulated translocation of Arf to membrane was suppressed only at concentrations of CYL-26z up to 30 microM. CYL-26z inhibited the fMLP-stimulated membrane expression of CD11b, CD45 and CD63, and the release of lysozyme and beta-glucuronidase. These results indicate that CYL-26z inhibited the fMLP-stimulated PLD activity, mainly through the blockade of RhoA activation, and degranulation in rat neutrophils.
Kuan
Yu-Hsiang
YH
Institute of Medicine, Chung Shan Medical University, Taichung, Taiwan, ROC.
Lin
Ruey-Hseng
RH
Tsao
Lo-Ti
LT
Chen
Yeh-Long
YL
Tzeng
Cherng-Chyi
CC
Wang
Jih-Pyang
JP
D000166:Acridines / Q000494:pharmacology*; D000818:Animals; D015550:Cell Degranulation / Q000187:drug effects; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005663:Furans / Q000494:pharmacology*; D047468:Immunoprecipitation; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology*; D009504:Neutrophils / Q000187:drug effects* / Q000201:enzymology; D010739:Phospholipase D / Q000037:antagonists & inhibitors* / Q000378:metabolism; D010766:Phosphorylation; D051381:Rats; D017207:Rats, Sprague-Dawley; D014443:Tyrosine / Q000378:metabolism; D020742:rhoA GTP-Binding Protein / Q000037:antagonists & inhibitors* / Q000378:metabolism
C504217:5-(4-acridin-9-ylamino)phenyl-5-methyl-3-methylenedihydrofuran-2-one; D000166:Acridines; D004791:Enzyme Inhibitors; D005663:Furans; D014443:Tyrosine; D009240:N-Formylmethionine Leucyl-Phenylalanine; D010739:Phospholipase D; D020742:rhoA GTP-Binding Protein