Zheng Xueyan, Karsan Aly, Duronio Vincent, Chu Fanny, Walker David C, Bai Tony R, Schellenberg R Robert
iCAPTURE Center, McDonald Research Laboratory, University of British Columbia, St. Paul's Hospital, 1081 Burrard Street, Vancouver, BC, Canada V6Z 1Y6.
Immunology. 2002 Nov;107(3):306-15. doi: 10.1046/j.1365-2567.2002.01517.x.
Basophils are key effector cells of allergic reactions. Although proinflammatory cytokines, such as interleukin (IL)-3, granulocyte-macrophage colony-stimulating factor (GM-CSF) and IL-5, inhibit eosinophil apoptosis in vitro, little is known about basophil apoptosis, and the signalling mechanisms required for basophil survival remain undefined. To address this issue, we used a novel negative-selection system to isolate human basophils to a purity of > 95%, and evaluated apoptosis by morphology using light and transmission electron microscopy, and by annexin-V binding and propidium iodide incorporation using flow cytometry. In this study, we demonstrated that the spontaneous rate of apoptotic basophils was higher than that of eosinophils as, at 24 hr, 57.6 +/- 4.7% of basophils underwent apoptosis compared with 39.5 +/- 3.8% of eosinophils. In addition, basophil cell death was significantly inhibited when cultured with IL-3 for 48 hr (84.6 +/- 4.9% vehicle-treated cells versus 40.9 +/- 3.9% IL-3-treated cells). IL-3 also up-regulated basophil CD69 surface expression. The effects of IL-3 on apoptosis and CD69 surface expression of human basophils were completely blocked by LY294002 (LY), a potent inhibitor of phosphatidylinositol 3-kinase (PI3-K), but only partially inhibited by lactacystin, a proteasome inhibitor that prevents degradation of IkappaB and NF-kappaB translocation. These observations reveal the novel finding that IL-3 prevents basophil apoptosis through the activation of PI3-K, which is only partially NF-kappaB dependent. As basophils are active participants in allergic reactions and IL-3 is one of the abundant proinflammatory cytokines in secretions from allergic tissue, we suggest that IL-3-mediated inhibition of basophil apoptosis may exacerbate the inflammation associated with allergic disorders.
嗜碱性粒细胞是过敏反应的关键效应细胞。尽管促炎细胞因子，如白细胞介素（IL）-3、粒细胞-巨噬细胞集落刺激因子（GM-CSF）和IL-5在体外可抑制嗜酸性粒细胞凋亡，但关于嗜碱性粒细胞凋亡的了解甚少，嗜碱性粒细胞存活所需的信号传导机制仍不明确。为解决这一问题，我们使用了一种新型阴性选择系统将人嗜碱性粒细胞分离至纯度>95%，并通过光学和透射电子显微镜观察形态以及使用流式细胞术检测膜联蛋白-V结合和碘化丙啶掺入来评估凋亡情况。在本研究中，我们证明嗜碱性粒细胞的自发凋亡率高于嗜酸性粒细胞，因为在24小时时，57.6±4.7%的嗜碱性粒细胞发生凋亡，而嗜酸性粒细胞为39.5±3.8%。此外，用IL-3培养48小时后，嗜碱性粒细胞死亡受到显著抑制（未处理细胞为84.6±4.9%，IL-3处理细胞为40.9±3.9%）。IL-3还上调了嗜碱性粒细胞CD69的表面表达。磷脂酰肌醇3-激酶（PI3-K）的强效抑制剂LY294002（LY）可完全阻断IL-3对人嗜碱性粒细胞凋亡和CD69表面表达的影响，但蛋白酶体抑制剂乳胞素仅部分抑制其作用，乳胞素可防止IkappaB降解和NF-kappaB易位。这些观察结果揭示了一个新发现，即IL-3通过激活PI3-K来防止嗜碱性粒细胞凋亡，且该过程仅部分依赖于NF-kappaB。由于嗜碱性粒细胞是过敏反应的积极参与者，且IL-3是过敏组织分泌物中丰富的促炎细胞因子之一，我们认为IL-3介导的嗜碱性粒细胞凋亡抑制可能会加剧与过敏性疾病相关的炎症。
