Jung In Duk, Lee Hyun-Sil, Lee Hoi Young, Choi Oksoon Hong
Department of Medicine, Division of Allergy and Clinical Immunology, The Johns Hopkins University School of Medicine, Baltimore, MD 21224, USA.
Cell Signal. 2009 Nov;21(11):1698-705. doi: 10.1016/j.cellsig.2009.07.008. Epub 2009 Jul 24.
IgE-sensitized rat basophilic leukemia (RBL)-2H3 mast cells have been shown to migrate towards antigen. In the present study we tried to identify the mechanism by which antigen causes mast cell migration. Antigen caused migration of RBL-2H3 cells at the concentration ranges of 1000-fold lower than those required for degranulation and the dose response was biphasic. This suggests that mast cells can detect very low concentration gradients of antigen (pg/ml ranges), which initiate migration until they degranulate near the origin of antigen, of which concentration is in the ng/ml ranges. Similar phenomenon was observed in human mast cells (HMCs) derived from CD34(+) progenitors. As one mechanism of mast cell migration, we tested the involvement of sphingosine 1-phosphate (S1P). Fc epsilon RI-mediated cell migration was dependent on the production of S1P but independent of a S1P receptor or its signaling pathways as determined with S1P receptor antagonist VPC23019 and Gi protein inhibitor pertussis toxin (PTX). This indicated that the site of action of S1P produced by antigen stimulation was intracellular. However, S1P-induced mast cell migration was dependent on S1P receptor activation and inhibited by both VPC23019 and PTX. Cell migration towards antigen or extracellular S1P was dependent on the activation of the phosphatidylinositol 3-kinase (PI3K) and mitogen-activated protein kinase (MAPK) pathways, while only migration towards antigen was inhibited by the inhibitors of sphingosine kinase and phospholipase C (PLC) and intracellular calcium chelator BAPTA. In summary, our data suggest that the high affinity receptor for IgE (Fc epsilon RI)-mediated mast cell migration is dependent on the production of S1P but independent of S1P receptors. Cell migration mediated by either Fc epsilon RI or S1P receptors involves activation of both PI3K and MAPK.
已证明IgE致敏的大鼠嗜碱性白血病（RBL）-2H3肥大细胞会向抗原迁移。在本研究中，我们试图确定抗原导致肥大细胞迁移的机制。抗原在比脱颗粒所需浓度低1000倍的范围内即可引起RBL-2H3细胞迁移，且剂量反应呈双相性。这表明肥大细胞能够检测到非常低浓度梯度的抗原（皮克/毫升范围），这种抗原浓度梯度会引发迁移，直到它们在抗原来源附近脱颗粒，此时抗原浓度处于纳克/毫升范围。在源自CD34(+)祖细胞的人肥大细胞（HMC）中也观察到了类似现象。作为肥大细胞迁移的一种机制，我们测试了鞘氨醇-1-磷酸（S1P）的参与情况。FcεRI介导的细胞迁移依赖于S1P的产生，但与S1P受体或其信号通路无关，这是通过S1P受体拮抗剂VPC23019和Gi蛋白抑制剂百日咳毒素（PTX）确定的。这表明抗原刺激产生的S1P的作用位点在细胞内。然而，S1P诱导的肥大细胞迁移依赖于S1P受体激活，并受到VPC23019和PTX的抑制。细胞向抗原或细胞外S1P的迁移依赖于磷脂酰肌醇3激酶（PI3K）和丝裂原活化蛋白激酶（MAPK）途径的激活，而只有向抗原的迁移受到鞘氨醇激酶和磷脂酶C（PLC）抑制剂以及细胞内钙螯合剂BAPTA的抑制。总之，我们的数据表明，IgE高亲和力受体（FcεRI）介导的肥大细胞迁移依赖于S1P的产生，但与S1P受体无关。由FcεRI或S1P受体介导的细胞迁移都涉及PI3K和MAPK的激活。
