Molecular Hierarchies in Salivary Adaptive Responses

描述(申请人提供)：这项拟议的研究旨在阐明建立分子层次反应的信号转导机制。 对唾液上皮细胞的低氧挑战。我们目前对这一问题的研究 唾液信号转导通路的特征导致了 一种新的非受体酪氨酸激酶ETK/BMX的鉴定 大鼠腮腺和大鼠唾液PA-4上皮细胞。我们证明了这一点 细胞旁屏障功能与低氧反应元件依赖 唾液中ETK的激活可增强PA-4的基因表达 细胞。在本应用程序中，我们将测试ETK调制 紧密连接成分(S)与其相互作用蛋白(S)的相互作用 用于在低氧条件下维持上皮完整性。我们会 也要检验ETK作为“分子开关”来激活的假设。 依赖HRE的转录，从而为细胞提供了 在长时间的低氧中存活。这项研究的长期目标是使用 ETK介导的细胞和生化调控及基因调控 唾液PA-4细胞作为解释机制等级的范例 信号通路的激活将适应性反应引导到 环境压力。拟议的研究具有重要意义，因为 信号通路和/或缺氧反应的失调与 人类的许多疾病，如缺血再灌注和唾液肿瘤。那里 在本申请中有四个具体目标：(I)确立 唾液上皮紧密连接中ETK依赖的磷酸化 在低氧条件下组装/拆卸；(Ii)建立 ETK促进紧密连接组装并增强唾液上皮屏障 常氧和低氧条件下的功能；(Iii)确定ETK是否被激活 是调节唾液上皮低氧诱导基因的关键 表达；以及(Iv)验证和表征选定的ETK激活诱导 靶基因，介导对长时间低氧暴露的适应性反应 唾液上皮细胞。这些结果将提供一个新的维度 唾液上皮适应性中ETK介导的信号转导途径和机制 对缺氧的反应。对分子基础有更深入的了解 ETK激活及其对细胞、生化和基因组事件的影响 生理条件是未来组织工程成功的关键 和药物发现。

DESCRIPTION (provided by applicant): The proposed study intends to elucidate signal transduction mechanisms that establish molecular hierarchies in response to hypoxic challenges in salivary epithelial cells. Our current studies on the characterization of salivary signal transduction pathways have led to the identification of a novel non-receptor tyrosine kinase, Etk/BMX, expressed in rat parotid glands and rat salivary Pa-4 epithelial cells. We demonstrated that the paracellular barrier function and hypoxia-response element (HRE)-dependent gene expression could be enhanced upon the activation of Etk in salivary Pa-4 cells. In this application, we will test the hypothesis that Etk modulates the interplay between tight junctional component(s) and its interacting protein(s) for the maintenance of epithelial integrity under hypoxic condition. We will also test the hypothesis that Etk serves as a "molecular switch" to activate the HRE-dependent transcription, thereby providing cells the capacity to survive prolonged hypoxia. The long-term goal of this research is to use Etk-mediated cellular and biochemical modulations and gene regulation in salivary Pa-4 cells as a paradigm to elucidate mechanistic hierarchies in which the activation of a signaling pathway directs the adaptive responses to environmental stress. The proposed study is of great significance as the dysregulation of signaling pathway and/or hypoxia responses is associated with many human diseases, such as ischemic reperfusion and salivary tumors. There are four Specific Aims in this application: (i) To establish the role of Etk-dependent phosphorylation in salivary epithelial tight junction assembly/disassembly under hypoxia; (ii) To establish the mechanism by which Etk promotes tight junction assembly and enhances salivary epithelial barrier functions under normoxia and hypoxia; (iii) To determine whether Etk activation is essential for modulating salivary epithelial hypoxia-induced gene expression; and (iv) To verify and characterize selected Etk activation-induced target genes, which mediate adaptive responses to prolonged hypoxic exposure in salivary epithelial cells. These results will provide a new dimension to the Etk-mediated signaling pathways and mechanisms in salivary epithelial adaptive responses to hypoxia. A better knowledge of the molecular basis of Etk-activation and its effect on cellular, biochemical and genomic events under (patho) physiological conditions is key to successful future tissue engineering and drug discovery.