Bulger E M, Garcia I, Maier R V
Department of Surgery, University of Washington, Seattle 98195, USA.
Shock. 1998 Jun;9(6):397-405. doi: 10.1097/00024382-199806000-00002.
The tissue-fixed macrophage (Mphi) plays a key role in coordinating the excessive inflammatory response following shock or sepsis. Reactive oxygen intermediates have been recently described as second messengers involved in signal transduction in these cells, including the activation of the transcription factors NF-kappaB and AP-1. The dithiocarbamates are potent antioxidants that inhibit NF-kappaB activation. We postulated that dithiocarbamates would inhibit Mphi activation via inhibition of NF-kappaB. Rabbit alveolar Mphi were obtained by bronchoalveolar lavage and exposed to either pyrrolidine dithiocarbamate (PDTC) or diethyl dithiocarbamate (DDTC) followed by stimulation with LPS (10 ng/mL). Supernatants were analyzed for TNF and prostaglandin E2, (PGE2) and F2-isoprostane (ISP), a marker of membrane lipid peroxidation, production at 18 h. PDTC and DDTC significantly enhanced production of TNF while inhibiting PGE2 and ISP production compared with LPS alone (p < .05). Northern blots revealed increased mRNA for TNF after pretreatment with PDTC, compared with LPS alone. Western blots and oligonucleotide gel shifts of nuclear proteins revealed inhibition of NF-kappaB activation by both PDTC and DDTC. AP-1 activity was shifted to earlier time points by PDTC pretreatment. These results demonstrate transcriptional and functional enhancement of TNF production despite inhibition of NF-kappaB activation. This may be due in part to a loss of autocrine feedback inhibition by PGE2 and enhancement of AP-1 activity. On the basis of these results, we conclude NF-kappaB may be necessary but, in contrast to prior analyzes, is not sufficient for optimal response of the alveolar Mphi to endotoxin.
组织固定巨噬细胞（Mphi）在协调休克或脓毒症后的过度炎症反应中起关键作用。活性氧中间体最近被描述为参与这些细胞信号转导的第二信使，包括转录因子NF-κB和AP-1的激活。二硫代氨基甲酸盐是有效的抗氧化剂，可抑制NF-κB激活。我们推测二硫代氨基甲酸盐会通过抑制NF-κB来抑制Mphi激活。通过支气管肺泡灌洗获得兔肺泡Mphi，将其暴露于吡咯烷二硫代氨基甲酸盐（PDTC）或二乙二硫代氨基甲酸盐（DDTC），然后用脂多糖（10 ng/mL）刺激。在18小时时分析上清液中的肿瘤坏死因子（TNF）、前列腺素E2（PGE2）和F2-异前列腺素（ISP，膜脂质过氧化的标志物）的产生。与单独使用脂多糖相比，PDTC和DDTC显著增强了TNF的产生，同时抑制了PGE2和ISP的产生（p <.05）。Northern印迹显示，与单独使用脂多糖相比，用PDTC预处理后TNF的mRNA增加。核蛋白的Western印迹和寡核苷酸凝胶迁移显示PDTC和DDTC均抑制NF-κB激活。PDTC预处理使AP-1活性转移到更早的时间点。这些结果表明，尽管抑制了NF-κB激活，但TNF产生的转录和功能增强。这可能部分归因于PGE2自分泌反馈抑制的丧失和AP-1活性的增强。基于这些结果，我们得出结论，NF-κB可能是必要的，但与先前的分析相反，对于肺泡Mphi对内毒素的最佳反应而言并不充分。
