NA/H EXCHANGE (NHE) AND ALVEOLAR EPITHELIAL CELL BIOLOGY

描述 (改编自申请人摘要)肺泡上皮细胞(AEC) 覆盖肺泡表面，这是排酸的主要部位 哺乳动物的器官。维持细胞内pH(Phi)是至关重要的 AEC的细胞内动态平衡因子。PHI和酸/碱 调节phi的转运蛋白也可能是 不同过程的信号转导和调节，包括细胞 生长和分化。候选人已经确定了肺泡 上皮细胞PHI受几种离子转运机制的调节 能够实现酸/碱从电池中进入或挤出，以及 也表明AEC表达哺乳动物Na/H的NHE1亚型 它们的基侧细胞膜上有交换器(NHE)。该计划的目标 这里提出的研究是为了进一步表征酸/碱运输和 肺泡上皮细胞的动态平衡及其关系的研究 NHE1的表达和活性与肺泡上皮细胞生物学的关系 候选人将使用生长在 组织培养处理过的聚碳酸酯过滤器上的原代培养 这些研究。该模型特别适合于AEC的研究。 酸/碱运输，上皮细胞极性，生长和 差异化。在可能的情况下，候选人将验证他的结果 对大鼠肺泡上皮细胞进行原位研究。基于实验数据 他正在进行的肺泡上皮酸/碱转运研究结果 和细胞内pH调节，他开始对测试 假设(1)NHE1通过以下途径促进血管内皮细胞内稳态 作为一种信号转导机制；(2)NHE1在 AEC以细胞特异性的方式；(3)NHE1的调节对于 肺泡上皮细胞生长和分化。为了测试这些 假设，候选人将调查以下具体目标： (#L)研究NHE1的基底侧方表达与神经营养因子的关系 胞外环境对胞内pH的影响；(#2)至 确定NHE1在细胞变化的动态平衡反应中的作用 体积和渗透压之间的关系；以及(#3)研究NHE1与 活性、细胞内pH和肺泡上皮细胞分化。 该项目的长期目标是将NHE定义为 血管内皮细胞的信号转导和细胞调控机制，包括 除了它在维持肺泡上皮细胞中的名义作用之外 细胞pH值。

DESCRIPTION (Adapted from the applicant's abstract) Alveolar epithelial cells (AEC) cover the alveolar surface of the lung, which is the major acid-excreting organ in mammals. Maintenance of intracellular pH (pHi) is a critical factor for intracellular homeostasis in AEC. pHi and the acid/base transport proteins that modulate pHi may also be important mechanisms for signal transduction and regulation of diverse processes, including cell growth and differentiation. The candidate have established that alveolar epithelial cell pHi is regulated by several ion transport mechanisms that are capable of effecting acid/base entry or extrusion from the cell, and have also shown that AEC express the NHE1 isoform of the mammalian Na/H exchanger (NHE) on their basolateral cell membranes. The objectives of the studies proposed herein are to further characterize acid/base transport and homeostasis in alveolar epithelial cells, and to study the relationship between NHE1 expression and activity and alveolar epithelial cell biology. The candidate will use monolayers of rat alveolar epithelial cells grown in primary culture on tissue-culture treated polycarbonate filters for many of these studies. This model is especially well suited for studies of AEC acid/base transport, epithelial cell polarity, and growth and differentiation. Where possible, the candidate will validate his results using in situ studies on rat alveolar epithelium. Based on the experimental results of his ongoing studies of alveolar epithelial acid/base transport and intracellular pH regulation, he became interested in testing the hypotheses that (1) NHE1 contributes to intracellular homeostasis in AEC by functioning as a mechanism of signal transduction; (2) NHE1 is regulated in AEC in a cell-specific fashion; (3) Regulation of NHE1 is important for alveolar epithelial cell growth and differentiation. In order to test these hypothesis, the candidate will investigate the following Specific Aims: (#l) To study the relationship between basolateral expression of NHE1 and the effects of the extracellular milieu on intracellular pH; (#2) To determine the role of NHE1 in homeostatic responses to changes in cell volume and osmolarity; and (#3) To investigate the relationship among NHE1 activity, intracellular pH, and alveolar epithelial cell differentiation. The long-term goals of this project are to define the role of NHE as a mechanism of signal transduction and cell regulation in AECs, inclusive of and in addition to its nominal role in maintenance of alveolar epithelial cell pH.