Inhibition of formyl-methionyl-leucyl-phenylalanine-stimulated phospholipase D activation in rat neutrophils by the synthetic isoquinoline DMDI.
The expression of phospholipase D (PLD) isoenzymes in neutrophils was investigated using reverse transcription-polymerase chain reaction analysis. Amplification products of predicted size were obtained from rat neutrophils with nucleotide sequences corresponding to PLD1a and PLD2. 1-(3',4'-Dimethoxybenzyl)-6,7-dichloroisoquinoline (DMDI) inhibited the formyl-methionyl-leucyl-phenylalanine (fMLP)-stimulated PLD activation in rat neutrophils. The underlying cellular signaling mechanism of DMDI inhibition was investigated. The fMLP-induced protein tyrosine phosphorylation and the membrane translocation of ADP-ribosylation factor (ARF) and Rho A in neutrophils was attenuated by DMDI in a concentration-dependent manner. However, neither the membrane association of protein kinase C-alpha and -beta isoenzymes in fMLP-stimulated cells nor the GTPgammaS- and phorbol 12-myristate 13-acetate-stimulated membrane translocation of ARF and Rho A in a cell-free system was affected significantly by DMDI. These results indicate that the expression of PLD1a and PLD2 mRNA in neutrophils. Attenuation of protein tyrosine phosphorylation and the membrane association of ARF and Rho A probably play a concerted role in the inhibition of PLD by DMDI in rat neutrophils in response to fMLP.
Chang
Ling-Chu
LC
Department of Education and Research, Taichung Veterans General Hospital, 160, Chung Kang Road, Sec. 3, Taiwan, ROC.
Chen
Chi-Ming
CM
Wang
Jih-Pyang
JP
D020823:ADP-Ribosylation Factor 1 / Q000378:metabolism; D000818:Animals; D002462:Cell Membrane / Q000187:drug effects / Q000201:enzymology; D002474:Cell-Free System; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D007527:Isoenzymes / Q000037:antagonists & inhibitors / Q000378:metabolism; D007546:Isoquinolines / Q000494:pharmacology*; D009240:N-Formylmethionine Leucyl-Phenylalanine; D009504:Neutrophils / Q000187:drug effects / Q000201:enzymology*; D010739:Phospholipase D / Q000037:antagonists & inhibitors* / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D011493:Protein Kinase C / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction; D020742:rhoA GTP-Binding Protein / Q000378:metabolism
C456601:1-(3',4'-dimethoxybenzyl)-6,7-dichloroisoquinoline; D004791:Enzyme Inhibitors; D007527:Isoenzymes; D007546:Isoquinolines; D012333:RNA, Messenger; D009240:N-Formylmethionine Leucyl-Phenylalanine; D011493:Protein Kinase C; D010739:Phospholipase D; D020823:ADP-Ribosylation Factor 1; D020742:rhoA GTP-Binding Protein