Expression, function and regulation of renal claudins

描述(由申请人提供)：父母资助的长期目标是确定上皮细胞旁细胞渗透的结构和功能决定因素。我们以前开发了一个模型，利用在MDCK I细胞中诱导Claudin-2的过表达来研究Claudin-2阳离子孔的性质。母公司的资助有3个具体目标，重点是描述claudin-2的功能特性，确定其阳离子选择性的基础，以及绘制孔的结构图。这一修订应用的推动力是我们的合作者Michael Fromm最近的发现，Claudin-2也显著增加了跨上皮水的通透性。目前的申请旨在通过增加第四个具体目标来扩大母公司赠款的范围，以表征Claudin-2诱导透水性的机制。这将产生新的信息，这些信息本身是全新的和具有生理意义的，但也将增加由其他三个具体目标产生的数据，以增强我们对毛孔结构的整体理解。此外，在最初的目的中产生的改变离子选择性和电导性的突变可以被用来探索在这个新的目的中水渗透的潜在机制。因此，拟议的新目标与母项赠款的最初目标之间将产生重大的概念和实验上的协同效应。这次修订将加快由父母资助的科学研究的节奏。预计它将通过资助雇用一名新的研究生，并为该项目采购所需的设备，包括用于测量水流的定制Ussing小室，来刺激经济。 公共卫生相关性：首席研究员：Yu，Alan S.L.叙述本项目旨在了解基于Claudin的毛孔的结构-功能关系以及盐分和水的渗透机制。这可能最终导致确定由异常的细胞旁通透性引起的疾病，其中可能包括各种形式的盐敏感型高血压、盐耗或尿崩症。这也可能导致针对克拉丁孔区的药物的开发，这种药物可以调节细胞旁的通透性，并作为尿液电解质排泄的调节器。

DESCRIPTION (provided by applicant): The long-term goal of the parent grant is to determine the structural and functional determinants of paracellular permeation in epithelia. We previously developed a model using inducible overexpression of claudin-2 in MDCK I cells to study the properties of the claudin-2 cation pore. The parent grant had 3 specific aims, focused on characterizing the functional properties of claudin-2, identifying the basis of its cation selectivity, and mapping the structure of the pore. The impetus for this revision application is the recent discovery by our collaborator, Michael Fromm, that claudin-2 also substantially increases transepithelial water permeability. The current application seeks to expand the scope of the parent grant by adding a 4th specific aim, to characterize the mechanism of claudin-2-induced water permeability. This will generate new information that is itself entirely novel and physiologically significant, but will also add to the data generated by the other three specific aims to enhance our overall understanding of the structure of the pore. Furthermore, mutants generated in the original aims that alter ion selectivity and conductance can be exploited to probe the underlying mechanism of water permeability in this new aim. Thus, there will be substantial conceptual and experimental synergy between the proposed new aim and the original aims of the parent grant. This revision will accelerate the tempo of scientific research funded by the parent grant. It is expected to stimulate the economy by funding the hiring of a new graduate student, and procuring needed equipment for this project, including custom Ussing chambers for water flow measurements. PUBLIC HEALTH RELEVANCE: Principal Investigator: YU, Alan S. L. NARRATIVE This project seeks to understand the structure-function relationship of claudin-based pores and the mechanism for salt and water permeation. This may eventually lead to the identification of diseases that are due to abnormal paracellular permeability, which might include forms of salt-sensitive hypertension, salt-wasting, or diabetes insipidus. It may also lead to the development of drugs targeted to the claudin pore region that could modulate paracellular permeability and act as modulators of urinary electrolyte excretion.