The blockade of formyl peptide-induced respiratory burst by 2',5'-dihydroxy-2-furfurylchalcone involves phospholipase D signaling in neutrophils.
The inhibition of formyl-methionyl-leucyl-phenylalanine (fMLP)-induced respiratory burst by 2',5'-dihydroxy-2-furfurylchalcone (DHFC) was investigated in rat neutrophils, and the underlying mechanism of this inhibition was assessed. DHFC concentration-dependently inhibited superoxide anion (O(2)) generation (IC(50) 4.2+/-1.2 microM), reaching a plateau within 5-10 min preincubation time, and inhibited oxygen consumption (IC(50) 6.9+/-1.9 microM) in rat neutrophils. In cell-free systems, DHFC failed to scavenge the generated during dihydroxyfumaric acid auto-oxidation. DHFC was less effective in the inhibition of both phorbol 12-myristate 13-acetate-activated neutrophil particulate NADPH oxidase activity and arachidonic acid-induced NADPH oxidase activation. In rat neutrophils, DHFC did not exert a cAMP-elevating effect, nor did it affect fMLP-induced [Ca(2+)](i) change to a considerable extent. DHFC slightly reduced fMLP-induced phosphatidylinositol 3-kinase (PI3 K) activation but showed moderate inhibition of Akt phosphorylation. fMLP-induced cellular phospholipase D (PLD) activation was markedly inhibited by DHFC (IC(50) 8.9+/-2.0 microM). In addition, DHFC effectively attenuated the membrane association of protein kinase C (PKC)-alpha, ADP-ribosylation factor (ARF) and Rho A in fMLP-stimulated cells. However, DHFC had no effect on the membrane association of ARF and Rho A caused by guanosine 5'-[gamma-thio]triphosphate (GTPgammaS) in cell lysate. fMLP-stimulated protein tyrosine phosphorylation was weakly attenuated by DHFC. DHFC was more efficient in the inhibition of extracellular signal-regulated kinase (ERK) phosphorylation than p38 mitogen-activated protein kinase (MAPK) phosphorylation. Collectively, these results indicate that the suppression of fMLP-induced respiratory burst by DHFC in rat neutrophils is probably mainly attributable to the inhibition of PLD activation, via the blockade of PKC-alpha, ARF and Rho A membrane association.
Wang
Jih-Pyang
JP
Department of Education and Research, Taichung Veterans General Hospital, 407, Taichung, Taiwan, Republic of China. w1994@vghtc.vghtc.gov.tw
Chang
Ling-Chu
LC
Hsu
Mei-Feng
MF
Lin
Chun-Nan
CN
D020727:ADP-Ribosylation Factors / Q000378:metabolism; D000818:Animals; D002478:Cells, Cultured; D002599:Chalcone / Q000031:analogs & derivatives / Q000494:pharmacology*; D047188:Chalcones; D000242:Cyclic AMP / Q000378:metabolism; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005663:Furans / Q000494:pharmacology*; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology*; D009504:Neutrophils / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D010739:Phospholipase D / Q000378:metabolism / Q000502:physiology*; D010766:Phosphorylation; D011493:Protein Kinase C / Q000378:metabolism; D064546:Protein Kinase C beta; D051571:Protein Kinase C-alpha; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt; D051381:Rats; D017207:Rats, Sprague-Dawley; D016897:Respiratory Burst / Q000187:drug effects* / Q000502:physiology; D015398:Signal Transduction; D013481:Superoxides / Q000378:metabolism
D020727:ADP-Ribosylation Factors; D002599:Chalcone; D047188:Chalcones; D000242:Cyclic AMP; D004791:Enzyme Inhibitors; D005663:Furans; D009240:N-Formylmethionine Leucyl-Phenylalanine; D019869:Phosphatidylinositol 3-Kinases; D010739:Phospholipase D; D011493:Protein Kinase C; D064546:Protein Kinase C beta; D051571:Protein Kinase C-alpha; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D051057:Proto-Oncogene Proteins c-akt; D013481:Superoxides; C488295:2',5'-dihydroxy-2-furfurylchalcone; C494920:Akt1 protein, rat