ALTERED COLLECTING TUBULE ION TRANSPORT IN ARPKD

描述：(直接取自申请)多囊肾病(PKD)在美国影响着50多万人，占所有接受透析或移植的终末期肾脏疾病患者的10%。这种疾病的特点是形成多个充满液体的囊肿，破坏肾脏结构并损害正常的肾功能。常染色体显性遗传性PKD(ADPKD)和常染色体隐性遗传性PKD(ARPKD)是由三个已知基因和几个尚未识别的基因突变引起的遗传病。基因产物的功能尚不清楚。人们普遍认为，细胞外基质的改变、细胞增殖的增强以及离子转运的改变伴随和/或驱动了囊变的形成。肾囊性上皮细胞分泌液体的能力以及EGF受体过度表达和错误定位的重要性最近已被证实。本项目的总体目标是确定囊性上皮细胞的离子转运表型，确定C1和液体分泌在囊性扩张中的重要性，并确定EGFR信号在ARPKD收集小管离子转运中的作用。我们的工作假设是，异常的EGFR信号有助于促进细胞增殖，并揭示了囊性上皮细胞的分泌表型。将进行肾切片器官培养、原代单层培养和条件永生化囊性和非囊性集合管细胞系的电生理学研究。将使用药理学和遗传学的方法来评估囊性上皮细胞对阿米洛利敏感的钠吸收、对钡敏感的钾分泌和环磷酸腺苷或钙激活的氯离子分泌的重要性。将评估心尖部和基底侧部EFGR信号对特定离子传输途径的影响。我们期待我们在小鼠ARPKD上的发现将加深我们对PKD细胞病理生理学的理解，并有助于设计常染色体隐性和常染色体显性人类PKD的治疗方法。

Description: (Taken directly from the application) Polycystic kidney diseases (PKD) affect more than 500,000 people in the United States and are responsible for 10% of all patients receiving dialysis or transplantation for end-stage renal disease. The disease is characterized by the formation of multiple fluid-filled cysts that disrupt renal architecture and compromise normal renal function. Autosomal dominant PKD (ADPKD) and autosomal recessive PKD (ARPKD) are genetic diseases caused by mutations in three known genes and several yet to be identified genes. The functions of the gene products are not known. It is widely accepted that there are changes in extracellular matrix, enhanced cell proliferation, and alterations in ion transport that accompany and/or drive cyst formation. The capacity of renal cystic epithelium to secrete fluid and the importance of EGF receptor overexpression and mislocalization have recently been established. The overall objective of this project to is to identify the ion transport phenotype of cystic epithelium, to establish the importance of C1 and fluid secretion in cyst expansion, and to determine the effect of EGFR signaling on collecting tubule ion transport in ARPKD. Our working hypothesis is that abnormal EGFR-signaling contributes to enhanced cell proliferation and unmasks a secretory phenotype in cystic epithelia. Electrophysiologic studies of renal slice organ culture, primary monolayer culture, and conditionally-immortalized cystic and non-cystic collecting tubule cell lines will be conducted. A pharmacologic and genetic approach will be used to evaluate the importance of amiloride-sensitive sodium absorption, barium-sensitive potassium secretion, and cAMP-or calcium-activated chloride secretion in cystic epithelia. The effect of apical and basolateral EFGR signaling on specific ion transport pathways will be evaluated. We anticipate that our findings with murine ARPKD will enhance our understanding of PKD cellular pathophysiology and contribute to the design of therapies for both autosomal recessive and autosomal dominant human PKD.