Mechanism of glomerulosclerosis on the basis of cell cycle reguration and differentiation of glomerular epithelial cells.

本研究旨在探讨肾小球上皮细胞（足细胞）细胞周期调控的机制。在1998年的第一年，我们发现细胞周期的静止和足细胞分化密切相关的人胎肾。细胞周期阻滞与细胞周期抑制因子p27和p57的上调密切相关。推测足细胞的细胞周期促进部分由细胞周期蛋白A，B1和D1决定。此外，我们发现CKIs在人类活检材料的细胞新月体和细胞病变的局灶性肾小球硬化低表达。这些增殖细胞几乎表达细胞角蛋白，表明壁上皮细胞表型。因此，佩奇补偿足细胞损失是一个实际的病理促进肾小球硬化。后肾器官培养显示p27上调，但p57与足细胞分化无关。因此p27在足细胞分化和细胞周期阻滞中起主导作用。接下来，我们研究了白细胞介素-4在足细胞培养中的作用。IL-4刺激足细胞形成穹隆状。因此，IL-4可以修饰细胞附着系统，即，焦点接触..最后，我们使用绿色荧光转基因小鼠来确定插入的启动子是否随着分化而被激活。胎肾和后肾培养系统显示毛细血管袢期足细胞发光。该杂合启动子的刺激物需要进一步研究。

This project was aimed to find the mechanism involving cell cycle reguration of glomerlular epithelial cells (podocytes). During first year of 1998, we found that cell cycle quiescent and podocyte differentiation was closely correlated in human fetal kidneys. Cell cycle stunt is tightly cassociated with up-regulation of cell cycle inhibitors, p27 and p57. Cell cycle promotion of presumptive podocytes was partly determined by cyclin A, B1 and D1. In addition, we found low expression of CKIs in cellular crescents and cellular lesion in focal glomeruloscleorsis in human biopsy materials. These proliferating cells virtually expressed cytokeratin indicating parietal epithelial cell phenotype. Thus PECs compensate podocyte loss is an actual pathology promoting glomerulosclerosis.The second year of 1999, we performed in vitro study. Metanephric organ culture showed up-reguration of p27, but not p57 in concert with podocyte differentiation. Thus p27 plays predominant role for the podocyte differentiation and cell cycle stunt. Next, we looked at the effect of Interleukin-4 in podocyte cell culture. We found IL4 stimulate podocyte cell line to form Dome shape. Thus IL-4 may modify cell attachment system, i.e., focal contact.. Finally we used green fluorescent transgenic mice to determine whether inserted promoter is activated with differentiation. Fetal kidneys and metanephric culture system demonstrated podocyte glowing in capillary loop stage. The stimulant for this hybrid promoter needs further investigation.