Wang H-B, Akuthota P, Kanaoka Y, Weller P F
Division of Allergy and Inflammation, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, University of California San Diego, San Diego, CA, USA.
Allergy. 2017 Jun;72(6):927-936. doi: 10.1111/all.13094. Epub 2017 Jan 11.
We previously demonstrated in mice that airway eosinophils traffic from the airway lumen into lung-draining paratracheal lymph nodes. However, mechanisms whereby eosinophils traverse from the lungs and home to paratracheal lymph nodes remain unclear. We investigated roles of cysteinyl leukotrienes in mediating eosinophil trafficking from lungs to paratracheal lymph nodes.
The expression of CCR7 was determined by flow cytometry. Transwell assays were used to test chemotactic responses of leukotriene C synthase-deficient and control airway eosinophils to the chemokine CCL19 ex vivo. Eosinophils from the spleens of IL-5 transgenic mice, fluorescently labeled ex vivo, were intratracheally injected into ovalbumin-sensitized and ovalbumin aerosol-challenged leukotriene C synthase-deficient and control mice. Eosinophils were identified by microscopy and flow cytometry in the lungs and paratracheal lymph nodes.
Mouse eosinophils expressed CCR7, the receptor for CCL19, and responded chemotactically to CCL19. Leukotriene C synthase-deficient eosinophils exhibited impaired chemotaxis to CCL19 that was restored by exogenous leukotriene C . The migration of intratracheally injected eosinophils into paratracheal lymph nodes from distal alveolar lung was diminished in leukotriene C synthase-deficient mice compared with wild-type mice, with increased retention of eosinophils in the lungs of leukotriene C synthase-deficient mice. Exogenous administration of leukotriene C restored trafficking of eosinophils to paratracheal lymph nodes in leukotriene C synthase-deficient mice.
Our findings that cysteinyl leukotrienes are involved in regulating airway and lung eosinophil migration into paratracheal lymph nodes identify previously unrecognized roles for the cysteinyl leukotrienes in regulating the pulmonary trafficking of eosinophils in experimental allergic asthma.
我们之前在小鼠中证明，气道嗜酸性粒细胞从气道腔迁移至引流肺的气管旁淋巴结。然而，嗜酸性粒细胞从肺穿越并归巢至气管旁淋巴结的机制仍不清楚。我们研究了半胱氨酰白三烯在介导嗜酸性粒细胞从肺向气管旁淋巴结迁移中的作用。
通过流式细胞术测定CCR7的表达。采用Transwell实验在体外测试白三烯C合酶缺陷型和对照气道嗜酸性粒细胞对趋化因子CCL19的趋化反应。将经体外荧光标记的IL-5转基因小鼠脾脏中的嗜酸性粒细胞经气管内注射到卵清蛋白致敏并经卵清蛋白气雾剂激发的白三烯C合酶缺陷型和对照小鼠体内。通过显微镜检查和流式细胞术在肺和气管旁淋巴结中鉴定嗜酸性粒细胞。
小鼠嗜酸性粒细胞表达CCL19的受体CCR7，并对CCL19产生趋化反应。白三烯C合酶缺陷型嗜酸性粒细胞对CCL19的趋化性受损，外源性白三烯C可使其恢复。与野生型小鼠相比，白三烯C合酶缺陷型小鼠中经气管内注射的嗜酸性粒细胞从远端肺泡肺向气管旁淋巴结的迁移减少，白三烯C合酶缺陷型小鼠肺中嗜酸性粒细胞的滞留增加。外源性给予白三烯C可恢复白三烯C合酶缺陷型小鼠中嗜酸性粒细胞向气管旁淋巴结迁移。
我们的研究结果表明，半胱氨酰白三烯参与调节气道和肺嗜酸性粒细胞向气管旁淋巴结的迁移，这确定了半胱氨酰白三烯在实验性过敏性哮喘中调节嗜酸性粒细胞肺内迁移方面以前未被认识的作用。
