Smart S J, Casale T B
Department of Internal Medicine, University of Iowa College of Medicine, Iowa City.
Am J Physiol. 1994 Mar;266(3 Pt 1):L238-45. doi: 10.1152/ajplung.1994.266.3.L238.
The early phases of airway inflammation include complex interactions between leukocytes, vascular endothelium, and inflammatory cytokines. Therefore, we examined tumor necrosis factor-alpha (TNF-alpha)-induced neutrophil migration through polycarbonate filters and human umbilical vein endothelial (HUVE) cells cultured as monolayers on these filters. TNF-alpha induced both dose- and time-dependent migration of neutrophils across both barriers. At 10(-11)-10(-9) M TNF-alpha, neutrophil migration across HUVE monolayers was more than twofold greater than that observed across naked filters. Modified checkerboard experiments indicated that neutrophils crossed naked filters as a chemokinetic rather than chemotactic response. Supernatants of TNF-alpha (10(-9) M)-stimulated HUVE monolayers induced threefold greater migration of neutrophils across naked filters than 10(-9) M TNF-alpha itself, suggesting release of soluble chemotactic factor(s). Pretreatment of HUVE monolayers with actinomycin D inhibited both TNF-alpha-induced production of soluble chemotactic factors and transendothelial neutrophil migration by > 90%. Supernatants from TNF-alpha-treated HUVE cells contained significant concentrations of interleukin 8 (IL-8), and coincubation of these supernatants with anti-IL-8 decreased supernatant-induced chemotaxis. Finally, coincubation of TNF-alpha with anti-IL-8 during transmigration experiments nearly completely inhibited the increase in neutrophil migration measured across HUVE monolayers. In contrast, WEB 2086, a platelet-activating factor receptor antagonist, had no effect. Therefore, endothelial cells greatly facilitate TNF-alpha-induced transcellular migration of neutrophils. This facilitation is dependent on TNF-alpha-stimulated production of IL-8. These data further support the active role of vascular endothelium in recruiting leukocytes to sites of inflammation.
气道炎症的早期阶段包括白细胞、血管内皮和炎症细胞因子之间的复杂相互作用。因此，我们研究了肿瘤坏死因子-α（TNF-α）诱导的中性粒细胞通过聚碳酸酯滤膜以及在这些滤膜上单层培养的人脐静脉内皮（HUVE）细胞的迁移情况。TNF-α诱导中性粒细胞穿越这两种屏障的迁移均呈剂量和时间依赖性。在10^(-11)-10^(-9) M的TNF-α浓度下，中性粒细胞穿越HUVE单层的迁移比穿越无细胞滤膜时观察到的迁移高出两倍多。改良棋盘实验表明，中性粒细胞穿越无细胞滤膜是一种化学动力学反应而非趋化反应。TNF-α（10^(-9) M）刺激的HUVE单层的上清液诱导中性粒细胞穿越无细胞滤膜的迁移比10^(-9) M的TNF-α本身诱导的迁移高出三倍，提示可溶性趋化因子的释放。用放线菌素D预处理HUVE单层可抑制TNF-α诱导的可溶性趋化因子的产生以及跨内皮中性粒细胞迁移达90%以上。TNF-α处理的HUVE细胞的上清液含有显著浓度的白细胞介素8（IL-8），这些上清液与抗IL-8共同孵育可降低上清液诱导的趋化作用。最后，在迁移实验中TNF-α与抗IL-8共同孵育几乎完全抑制了在HUVE单层上测量到的中性粒细胞迁移增加。相比之下，血小板活化因子受体拮抗剂WEB 2086没有作用。因此，内皮细胞极大地促进了TNF-α诱导的中性粒细胞跨细胞迁移。这种促进作用依赖于TNF-α刺激的IL-8产生。这些数据进一步支持了血管内皮在将白细胞募集到炎症部位中的积极作用。
