ENDOCYTOSIS IN CULTURED RENAL EPITHELIA

这些研究的长期目标是确定内吞作用的特征 肾上皮细胞，以便更好地了解内吞作用如何参与 在肾脏疾病的过程中。内吞作用是细胞的一项重要功能。 生物学上，在肾上皮细胞中起着特别重要的作用 参与排泄和吸收的功能。肾离子 转运部分受胞内插入和回收的调节 转运体，调节这种内吞运输的信号是 它们自身受到荷尔蒙的内吞作用的调节。小分子大分子在 肾小管滤液通过极高的顶端吞噬速率被回收。 在近端小管中，因此对 肾小管滤过液内容物，摄取导致肾小管损伤 过滤的氨基糖苷类抗生素和摄取过量的或 蛋白尿期间的有毒蛋白质。对成纤维细胞的研究已经建立 定量荧光显微镜可以用来表征 PH、融合可及性和配基积累动力学 在内小体中进行分类。细胞内的内吞动力学已经阐明 胞质分选机制及胞体pH的测定 确定了内体酸化在以下过程中的作用 溶酶体水解，病毒和毒素渗透到细胞质和 细胞内药物隔离。尽管这些过程对于 肾上皮细胞正常和病理功能的可比性研究 由于技术原因，尚未在极化的上皮细胞中进行 困难。随着改进的光学仪器的发展， 合适的数字图像处理技术和转基因模型细胞 系统，这些对上皮细胞的研究现在是可行的。具体来说， 拟议的研究将首先讨论内体pH的调节。 模型肾上皮细胞。完整而具体的描述 内体在循环、降解和跨细胞途径中的来源 从顶端和基底侧质膜域将进行 用荧光比率共聚焦显微镜观察活细胞。这个 内吞分选的机制也将用类似的 定量共聚焦显微镜技术。特定类型的 内体可以根据其内容物在功能上进行识别 不同配体在体内积累和流出的动力学 这些内小体可以阐明内吞分选的具体步骤。 调节或扰乱内含体的生物学相关因素 酸化和内吞运输也将被研究。这些 研究涉及内吞作用的基本过程，已被证明 对非极化细胞的正常细胞功能至关重要，但不是 已经在上皮细胞中进行了研究。由本网站提供的信息 这项研究将对上皮细胞生物学家和 肾脏生物学家试图了解肾脏的生理和病理 细胞过程。

The long term objective of these studies is to characterize endocytosis in renal epithelia in order to better understand how endocytosis participates in renal disease processes. Endocytosis is an important function in cell biology, and in kidney epithelia plays a particularly important role as it participates in the functions of excretion and resorption. Renal ion transport is partially regulated by endocytic insertion and retrieval of transporters, and the signals regulating this endocytic traffic are themselves regulated by endocytosis of hormones. Small macromolecules in the tubule filtrate are reclaimed via furious rates of apical endocytosis in the proximal tubule which is consequently particularly sensitive to the contents of the tubule filtrate, with tubular damage resulting from uptake of filtered aminoglycoside antibiotics and from the uptake of excessive or toxic proteins during proteinuria. Studies of fibroblasts have established that quantitative fluorescence microscopy may be used to characterize the pH, fusion accessibility and the kinetics of ligand accumulation and sorting in endosomes. The intracellular endocytic kinetics have elucidated mechanisms of endocytic sorting and measurements of endosome pH have established the role of endosome acidification in the processes of lysosomal hydrolysis, virus and toxin penetration into the cytosol and intracellular drug sequestration. Although these processes are critical to normal and pathological function of renal epithelia, comparable studies have not yet been conducted in polarized epithelial cells due to technical difficulties. With the development of improved optical instrumentation, appropriate digital image processing techniques and transfected model cell systems, these studies of epithelial cells are now feasible. Specifically, the proposed studies will first address the regulation of endosome pH in model renal epithelia. A complete and specific characterization of endosomes on the recycling, degradative and transcytotic pathways derived from the apical and basolateral plasma membrane domains will be conducted using fluorescence ratio confocal microscopy of living cells. The mechanisms of endocytic sorting will also be addressed, using similar techniques of quantitative confocal microscopy. Particular types of endosomes can be functionally identified on the basis of their contents and the kinetics with which different ligands accumulate in, and efflux from these endosomes can elucidate specific steps of endocytic sorting. Biologically relevant factors regulating or perturbing endosome acidification and endocytic trafficking will also be studied. These studies address fundamental processes of endocytosis which have proven to be critical to proper cell function in non-polarized cells, but have not been studied in epithelial cells. The information provided by this research will be valuable to both epithelial cell biologists and also to renal biologists seeking to understand physiological and pathological renal cellular processes.