Wang Jih-Pyang, Chang Ling-Chu, Hsu Mei-Feng, Lin Chun-Nan
Department of Education and Research, Taichung Veterans General Hospital, 407, Taichung, Taiwan, Republic of China.
Naunyn Schmiedebergs Arch Pharmacol. 2003 Sep;368(3):166-74. doi: 10.1007/s00210-003-0782-8. Epub 2003 Aug 20.
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+) 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.
研究了2',5'-二羟基-2-糠基查尔酮（DHFC）对大鼠中性粒细胞中N-甲酰甲硫氨酰-亮氨酰-苯丙氨酸（fMLP）诱导的呼吸爆发的抑制作用，并评估了这种抑制作用的潜在机制。DHFC浓度依赖性地抑制超氧阴离子（O₂）的产生（IC₅₀ 4.2±1.2 μM），在预孵育5 - 10分钟内达到平台期，并抑制大鼠中性粒细胞的耗氧量（IC₅₀ 6.9±1.9 μM）。在无细胞系统中，DHFC未能清除二羟基富马酸自氧化过程中产生的物质。DHFC对佛波酯12-肉豆蔻酸酯13-乙酸酯激活的中性粒细胞微粒体NADPH氧化酶活性和花生四烯酸诱导的NADPH氧化酶激活的抑制作用较弱。在大鼠中性粒细胞中，DHFC没有发挥升高cAMP的作用，也没有在很大程度上影响fMLP诱导的细胞内钙离子浓度（[Ca²⁺]i）变化。DHFC略微降低了fMLP诱导的磷脂酰肌醇3-激酶（PI3 K）激活，但对Akt磷酸化有中度抑制作用。fMLP诱导的细胞磷脂酶D（PLD）激活被DHFC显著抑制（IC₅₀ 8.9±2.0 μM）。此外，DHFC有效地减弱了fMLP刺激的细胞中蛋白激酶C（PKC）-α、ADP-核糖基化因子（ARF）和Rho A的膜结合。然而，DHFC对细胞裂解物中鸟苷5'-[γ-硫代]三磷酸（GTPγS）引起的ARF和Rho A的膜结合没有影响。fMLP刺激的蛋白酪氨酸磷酸化被DHFC微弱地减弱。DHFC对细胞外信号调节激酶（ERK）磷酸化的抑制作用比对p38丝裂原活化蛋白激酶（MAPK）磷酸化的抑制作用更有效。总的来说，这些结果表明，DHFC对大鼠中性粒细胞中fMLP诱导的呼吸爆发的抑制作用可能主要归因于通过阻断PKC-α、ARF和Rho A的膜结合来抑制PLD激活。
