Standiford T J, Kunkel S L, Basha M A, Chensue S W, Lynch J P, Toews G B, Westwick J, Strieter R M
University of Michigan Medical School, Department of Pathology, Ann Arbor 48109-0602.
J Clin Invest. 1990 Dec;86(6):1945-53. doi: 10.1172/JCI114928.
Cellular constituents of the alveolar-capillary wall may be key participants in the recruitment of polymorphonuclear leukocytes to the lung through the generation of the novel neutrophil chemotactic peptide interleukin-8 (IL-8). This interaction appears to occur via the ability of human alveolar macrophage (AM)-derived monokines, tumor necrosis factor (TNF), and interleukin-1 (IL-1) to induce gene expression of IL-8 from pulmonary type II-like epithelial cells (A549). Northern blot analysis demonstrated that steady-state IL-8 mRNA expression, by either TNF- or IL-1 beta-treated A549 cells, occurred in both a dose- and time-dependent fashion. Similarly, extracellular antigenic IL-8, as assessed by specific ELISA, was expressed from TNF- or IL-1 beta-stimulated epithelial cells in a time-dependent fashion with maximal IL-8 antigen detected at 24 h poststimulation. Immunohistochemical staining utilizing rabbit anti-human IL-8 antibody identified immunoreactive, cell-associated IL-8 antigen as early as 8 h post-TNF or IL-1 beta stimulation. A549-generated neutrophil chemotactic bioactivity paralleled IL-8 steady-state mRNA levels. Signal specificity was demonstrated in this system as IL-8 mRNA or protein expression by lipopolysaccharide (LPS)-treated A549 cells was not different from unstimulated cells. Although LPS did not serve as a direct stimulus for the production of IL-8 by type II-like epithelial cells, the condition media from LPS-challenged AM induced a significant expression of IL-8 mRNA by the A549 cells. 24-h conditioned media from LPS-treated cells was as potent as either IL-1 beta or TNF in generating steady-state IL-8 mRNA by A549 cells. Preincubation of LPS-treated AM-conditioned media with anti-human TNF or IL-1 beta neutralizing antibodies resulted in significant abrogation of IL-8 gene expression by A549 pulmonary epithelial cells. These findings demonstrate potential cell-to-cell communication circuits that may be important between AMs and pulmonary epithelial cells during the recruitment phase of acute lung inflammation.
肺泡 - 毛细血管壁的细胞成分可能是通过产生新型中性粒细胞趋化肽白细胞介素 - 8（IL - 8），将多形核白细胞募集到肺中的关键参与者。这种相互作用似乎是通过人肺泡巨噬细胞（AM）衍生的单核因子、肿瘤坏死因子（TNF）和白细胞介素 - 1（IL - 1）诱导II型样肺上皮细胞（A549）中IL - 8基因表达的能力而发生的。Northern印迹分析表明，TNF或IL - 1β处理的A549细胞中稳态IL - 8 mRNA表达呈剂量和时间依赖性。同样，通过特异性ELISA评估，细胞外抗原性IL - 8以时间依赖性方式从TNF或IL - 1β刺激的上皮细胞中表达，在刺激后24小时检测到最大IL - 8抗原。利用兔抗人IL - 8抗体的免疫组织化学染色最早在TNF或IL - 1β刺激后8小时就鉴定出免疫反应性的、与细胞相关的IL - 8抗原。A549产生的中性粒细胞趋化生物活性与IL - 8稳态mRNA水平平行。在该系统中证明了信号特异性，因为脂多糖（LPS）处理的A549细胞的IL - 8 mRNA或蛋白质表达与未刺激的细胞没有差异。虽然LPS不是II型样上皮细胞产生IL - 8的直接刺激物，但LPS刺激的AM的条件培养基诱导A549细胞中IL - 8 mRNA的显著表达。LPS处理细胞的24小时条件培养基在通过A549细胞产生稳态IL - 8 mRNA方面与IL - 1β或TNF一样有效。用抗人TNF或IL - 1β中和抗体预孵育LPS处理的AM条件培养基会导致A549肺上皮细胞中IL - 8基因表达的显著消除。这些发现表明，在急性肺炎症的募集阶段，AM和肺上皮细胞之间可能存在重要的潜在细胞间通讯回路。
