MEMBRANE PHYSIOLOGY IN MAST CELL DIFFERENTIATION

肥大细胞和免疫球蛋白E（IgE）在过敏和 哮喘，它们与炎症有关。在大多数物种中， 不同组织中的肥大细胞在功能上是异质的; 它们对促分泌素和抑制剂的反应明显不同， 分泌物，如抗哮喘药物crologyn;一些增殖， 响应IgE受体的交联而分泌淋巴因子，或 寄生虫感染和其他没有。与此功能相关的 异质性是结构和生物化学特化的标志。这 异质性和产生异质性的分化过程是 在啮齿类动物，尤其是大鼠中最好定义，其中两种肥大细胞亚型 公认的是粘膜肥大细胞（MMC）和血清肥大细胞。是 肥大细胞亚群的膜生理学可能不同， 这种差异可能有助于功能多样性。 抗原驱动的钙信号传导，例如，关键取决于细胞膜 电位，这反过来又由离子通道调节。长期 这项工作的目标是了解肥大细胞分化在 分子水平，这里的重点是在离子通道表达过程中 肥大细胞分化 虽然大鼠的离子通道库 部分表征了血清肥大细胞和转化的大鼠MMC， 正常大鼠MMC无相应数据。在这里，我们建议使用 膜片钳记录，以表征存在于初级 大鼠MMC和骨髓源性肥大细胞（BMMC），肥大细胞制剂 在体外分化的细胞非常类似MMC。我们将使用 荧光染料的数字成像显微镜来表征IgE- 介导的钙信号和膜电位的变化。 肥大细胞K~+通道在膜调节中的作用 电位、钙信号传导和分泌将被探索。最后， 选择性表达的离子通道将作为潜在的靶点进行测试， 药理学阻断过敏和炎症介质分泌， 抑制白细胞介素3依赖的大鼠骨髓基质细胞增殖。 这项工作将促进我们对肥大细胞异质性的理解， 提供了一个缺失的章节的离子通道生理大鼠粘膜 肥大细胞它也可能产生一种新的药理学策略， 过敏或哮喘的干预。

Mast cells and immunoglobulin E (IgE) play a pivotal role in allergies and asthma, and they are implicated in inflammation. In most species examined, mast cells localized in different tissues are functionally heterogeneous; their response varies markedly to secretagogues and inhibitors of secretion such as the anti-asthmatic drug cromolyn; some proliferate and secrete lymphokines in response to cross-linkage of IgE receptors or parasite infections and others do not. Associated with this functional heterogeneity is marked structural and biochemical specialization. This heterogeneity and the differentiation process that gives rise to it are best-defined in rodents, especially rats, where two mast cell subtypes are recognized, mucosal mast cells (MMC) and serosal mast cells. It is probable that the membrane physiology of mast cell subsets differs, and it is possible that such differences contribute to functional diversity. Antigen-driven calcium signaling, e.g., depends critically on membrane potential, and this in turn is regulated by ion channels. The long term goal of this work is to understand mast cell differentiation at the molecular level, and the focus here is on ion channel expression during mast cell differentiation. Although the ion channel repertoires of rat serosal mast cells and a transformed rat MMC are partially characterized, there are no corresponding data for normal rat MMC. Here we propose to use patch-clamp recording to characterize the ion channels present in primary rat MMC and bone marrow-derived mast cells (BMMC), a preparation of mast cells differentiated in vitro that closely resembles MMC. We will use digital imaging microscopy of fluorescent dyes to characterize IgE- mediated calcium signaling and membrane potential changes in MMC and BMMC. The possible role of mast cell K+ channels in regulation of membrane potential, calcium signaling, and secretion will be explored. Finally, selectively expressed ion channels will be tested as potential targets for pharmacological blockade of allergic and inflammatory mediator secretion, and for inhibition of interleukin-3 dependent proliferation of rat BMMC. This work will advance our understanding of mast cell heterogeneity and provide a missing chapter on the ion channel physiology of rat mucosal mast cells. It also could yield a new strategy for pharmacologic intervention in allergies or asthma.