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） 覆盖肺的肺泡表面，这是主要的排酸 哺乳动物的器官 维持细胞内pH值（pHi）是一个关键因素， AEC中细胞内稳态的因子。 pHi和酸/碱 调节pHi的转运蛋白也可能是 信号转导和调节多种过程，包括细胞 生长和分化。 候选人已经确定了肺泡 上皮细胞pHi由几种离子转运机制调节， 能够实现酸/碱进入或从细胞中挤出，和 也表明AEC表达哺乳动物Na/H的NHE 1同种型， 交换器（NHE）的基底外侧细胞膜。 的目标 本文提出的研究是进一步表征酸/碱转运， 肺泡上皮细胞的稳态，并研究其关系 NHE 1表达和活性与肺泡上皮细胞生物学之间的关系。 候选人将使用单层大鼠肺泡上皮细胞生长在 在组织培养处理的聚碳酸酯过滤器上进行原代培养， 这些研究。 该模型特别适合于AEC的研究 酸/碱转运、上皮细胞极性和生长， 分化 在可能的情况下，候选人将验证其结果 使用大鼠肺泡上皮的原位研究。 根据实验 他正在进行的肺泡上皮酸/碱转运研究的结果 和细胞内pH调节，他开始有兴趣测试 假设：（1）NHE 1通过以下方式促进AEC细胞内稳态： 作为信号转导机制发挥作用;（2）NHE 1在 （3）NHE 1的调节对于AEC的发生和发展具有重要意义。 肺泡上皮细胞的生长和分化。 为了测试这些 假设，候选人将调查以下具体目标： （#l）研究NHE 1的基底外侧表达与NHE 1的表达之间的关系。 细胞外环境对细胞内pH的影响;（#2）为了 确定NHE 1在细胞内环境变化的稳态反应中的作用， 体积和渗透压;以及（#3）研究NHE 1 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的作用定义为 AEC中的信号转导和细胞调节机制，包括 除了其在维持肺泡上皮细胞中的名义作用外， 细胞pH

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.