Spitzer J A, Zhang P
Department of Physiology, Louisiana State University Medical Center, New Orleans 70112, USA.
Shock. 1996 Dec;6(6):426-33. doi: 10.1097/00024382-199612000-00007.
The role of tyrosine phosphorylation in endotoxin-induced phagocytic and tumor necrosis factor secretory responses was studied in rat alveolar macrophages and lung-recruited neutrophils. Exploration of sexual dimorphism in some aspects of these functions was also a specific aim. Male and female rats were injected intratracheally with endotoxin or saline. Two and a half hours later the animals were subjected to bronchoalveolar lavage, and alveolar macrophages and lung-recruited neutrophils were isolated. Circulating neutrophils of endotoxin-treated rats were also isolated at this time. Phagocytosis and CD11b/c and CD18 expression were measured by flow cytometry; tumor necrosis factor was measured with a cytotoxicity assay. Using the protein tyrosine kinase inhibitor AG126 and phosphotyrosine immunoblotting, we demonstrated that tyrosine phosphorylation is an important signaling pathway in the activation of these cells by endotoxin and that it is coupled to phagocytosis and tumor necrosis factor secretion, but not to beta 2 integrin expression. Conditioned medium of alveolar macrophages of endotoxin-injected rats upregulates phagocytosis by blood neutrophils of naive rats and this upregulating activity is tyrosine phosphorylation dependent. The substrates for tyrosine phosphorylation are different in alveolar macrophages and lung neutrophils, as are their sensitivities to AG126. Significant gender differences exist in the modulation of phagocytosis by inhibition of tyrosine phosphorylation and in tumor necrosis factor secretion by endotoxin-stimulated alveolar macrophages.
在大鼠肺泡巨噬细胞和肺募集的中性粒细胞中，研究了酪氨酸磷酸化在内毒素诱导的吞噬和肿瘤坏死因子分泌反应中的作用。探索这些功能某些方面的性别差异也是一个特定目标。给雄性和雌性大鼠气管内注射内毒素或生理盐水。两个半小时后，对动物进行支气管肺泡灌洗，并分离肺泡巨噬细胞和肺募集的中性粒细胞。此时也分离内毒素处理大鼠的循环中性粒细胞。通过流式细胞术测量吞噬作用以及CD11b/c和CD18的表达；用细胞毒性测定法测量肿瘤坏死因子。使用蛋白酪氨酸激酶抑制剂AG126和磷酸酪氨酸免疫印迹法，我们证明酪氨酸磷酸化是内毒素激活这些细胞的重要信号通路，并且它与吞噬作用和肿瘤坏死因子分泌相关，但与β2整合素表达无关。注射内毒素的大鼠肺泡巨噬细胞的条件培养基上调未接触过内毒素的大鼠血液中性粒细胞的吞噬作用，并且这种上调活性依赖于酪氨酸磷酸化。肺泡巨噬细胞和肺中性粒细胞中酪氨酸磷酸化的底物不同，它们对AG126的敏感性也不同。在通过抑制酪氨酸磷酸化调节吞噬作用以及内毒素刺激的肺泡巨噬细胞分泌肿瘤坏死因子方面存在显著的性别差异。
