REGULATION OF NORMAL AND CYSTIC RENAL TUBULOGENESIS

肾小管形态发生和功能的发育异常是 多囊肾是一种主要的遗传性疾病， 在美国有超过50万人受到影响。 事业 这种疾病是未知的，但据推测，增加的细胞 增殖和改变的经前庭流体运输是重要的。 我们 长期目标是了解形态调节机制 参与正常肾小管上皮组织的发育， 并确定这些机制是否在发育过程中发生改变， 多囊肾病 我们已经建立了体外方法来分析 肾上皮细胞发育（transfilter培养物），以及 候选的形态发生因子在小管发生，将扩大到 分析来自cpk小鼠的囊性小管上皮细胞，cpk小鼠是一种 多囊肾病 我们的初步研究表明， Na/K-ATP酶的发育是短暂定位于顶端膜 结构域的正常细胞，但连续表达的顶端 囊状上皮细胞膜。 我们先前的结果表明， Na/K-ATP酶在基底-侧膜的正常分布为 由细胞与细胞的接触和与细胞膜的相互作用产生， 细胞骨架和膜脂。 我们将检验这个假设， 诱导肾小管形成的可溶性因子的异常调节， 发育可导致肾小管上皮细胞增殖增加 并且，结合顶端活性Na/K-ATP酶的保留 膜，形成囊性小管： 1.确定Na/K-ATP酶分布的时间和空间调节 在间充质诱导和转化为上皮细胞后， 正常发展。 Na/K-的表达和分布模式 将测定ATP酶、膜细胞骨架和膜脂质。 2.调节E-cadherin诱导的细胞间相互作用的时间， 间充质转化和上皮细胞分化。 的影响 抑制细胞-细胞接触对细胞分化和小管形成的影响 在培养中的后肾间充质诱导和转化期间， 被分析。 3.研究间充质诱导和上皮细胞分化， 来自CPK小鼠的后肾的transfilter培养物。 的表达模式 Na/K-ATP酶、膜骨架和膜脂的分布 将被确定并在时间和空间上与正常情况下的那些进行比较。 发展 4.分析可溶性因子的表达和功能， 体外正常和囊性上皮细胞的小管形成 分化和小管发生。 Scatter的表达和作用 因子/肝细胞生长因子（SC/HGF），一种有效的小管形成诱导剂 在体外肾上皮细胞中，将在以下培养物中进行检查： 从正常和囊性后肾发育肾小管， 纯化的正常和囊性上皮细胞群诱导形成 体外分支管状网络。

Developmental abnormalities in renal tubule morphogenesis and function are characteristic of polycystic kidney disease, a major genetic disorder in humans that affects over 500,000 people in the United Stats. The cause of the disease is unknown, but it has been postulated that increased cell proliferation and altered transtubular fluid transport are important. Our long term objectives are to understand the morphoregulatory mechanisms involved in the development of normal renal tubule epithelia organization, and to determine whether these mechanisms are altered during development of polycystic kidney disease. We have established in vitro methods to analyze renal epithelial cell development (Transfilter Cultures), and the role of candidate morphogenetic factors in tubulogenesis that will be extended to analyze cells from cystic tubule epithelia of cpk mice, a murine model of polycystic kidney disease. Our preliminary studies show that in early development Na/K-ATPase is transiently localized to the apical membrane domain of normal cells, but is continuously expressed on the apical membrane in cystic epithelial cells. Our previous results indicate that the normal distribution of Na/K-ATPase at the basal-lateral membrane is generated by cell-cell contact and interactions with the membrane- cytoskeleton and membrane lipids. We will test the hypothesize that abnormal regulation of soluble factors that induce tubulogenesis in development could lead to increased cell proliferation of tubular epithelia and, combined with the retention of active Na/K-ATPase on the apical membrane, the formation of cystic tubules: 1. Define the temporal and spatial regulation of Na/K-ATPase distribution following mesenchyme induction and conversion to epithelial cells during normal development. Patterns of expression and distribution of Na/K- ATPase, membrane-cytoskeleton, and membrane lipids will be determined. 2. Modulate the timing of E-cadherin-induced cell-cell interactions during mesenchyme conversion and epithelial cell differentiation. Effects of inhibiting cell-cell contacts on cell differentiation and tubulogenesis during metanephrogenic mesenchyme induction and conversion in culture will be analyzed. 3. Investigate mesenchyme induction and epithelial cell differentiation in transfilter cultures from metanephroi of CPK mice. Patterns of expression and distribution of Na/K-ATPase, membrane-cytoskeleton, and membrane lipids will be determined and compared temporally and spatially to those in normal development. 4. Analyze the expression and function of soluble factors, that regulate tubulogenesis in vitro, on normal and cystic epithelial cell differentiation and tubulogenesis. Expression and function of Scatter Factor/Hepatocyte Growth Factor (SC/HGF), a potent inducer of tubulogenesis in renal epithelial cells in vitro, will be examined in cultures of developing renal tubules from normal and cystic metanephroi, and in purified populations of normal and cystic epithelial cells induced to form branching tubular networks in vitro.