Lendemans Sven, Rani Meenakshi, Selbach Christian, Kreuzfelder Ernst, Schade Fritz Ulrich, Flohé Sascha
Department of Trauma Surgery, University Hospital of Essen, Essen, Germany.
J Endotoxin Res. 2006;12(1):10-20. doi: 10.1179/096805106X89107.
The ability to augment monocyte functions such as TNF-alpha-producing capacities confers a high immunostimulating potential to GM-CSF. In the present investigation, the mechanism of the GMCSF-mediated enhancement of monocyte cytokine production was analysed with regard to the involvement of intracellular signalling pathways. GM-CSF primes human monocytes dose- and time-dependently for enhanced LPS-stimulated TNF-alpha synthesis. Pre-incubation with 10 ng/ml GM-CSF for 6 h before LPS stimulation (10 ng/ml) caused a 3.4 +/- 1.9-fold increase in TNF-alpha release compared to unprimed controls. This was associated with increased phosphorylation of IkappaBalpha and elevated nuclear levels of the NF-kappaB components p50 and p65 and NF-kappaB binding to DNA. LPS-induced AP-1 binding to DNA was also enhanced in GM-CSF-pre-incubated cells. GMCSF treatment also caused a slight increase in TLR4 expression on monocytes while CD14 expression remained unchanged. GM-CSF-priming was unaffected by inhibitors of p38 MAPK (SB203580) and lipoxygenase (NDGA). In contrast, the broad-spectrum tyrosine kinase inhibitor genistein and the MEK-1 inhibitor (PD98059) abrogated GM-CSF priming of TNF-alpha release and activation of both NF-kappaB and AP-1. It is concluded that a tyrosine kinase of the GM-CSF-triggered ERK1/2 pathway augments the LPS-induced NF-kappaB and AP-1 activation.
增强单核细胞功能（如产生肿瘤坏死因子-α的能力）的特性赋予粒细胞-巨噬细胞集落刺激因子（GM-CSF）高度的免疫刺激潜力。在本研究中，针对细胞内信号通路的参与情况，分析了GM-CSF介导的单核细胞细胞因子产生增强的机制。GM-CSF以剂量和时间依赖性方式使人类单核细胞致敏，以增强脂多糖（LPS）刺激的肿瘤坏死因子-α合成。在LPS刺激（10 ng/ml）前用10 ng/ml GM-CSF预孵育6小时，与未致敏的对照相比，肿瘤坏死因子-α释放增加了3.4±1.9倍。这与IκBα磷酸化增加、NF-κB成分p50和p65的核水平升高以及NF-κB与DNA结合有关。在GM-CSF预孵育的细胞中，LPS诱导的AP-1与DNA结合也增强。GM-CSF处理还导致单核细胞上TLR4表达略有增加，而CD14表达保持不变。GM-CSF致敏不受p38丝裂原活化蛋白激酶（SB203580）和脂氧合酶（NDGA）抑制剂的影响。相反，广谱酪氨酸激酶抑制剂染料木黄酮和MEK-1抑制剂（PD98059）消除了GM-CSF对肿瘤坏死因子-α释放的致敏作用以及NF-κB和AP-1的激活。结论是，GM-CSF触发的ERK1/2途径中的酪氨酸激酶增强了LPS诱导的NF-κB和AP-1激活。
