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

本项目旨在发现肾小球上皮细胞（足细胞）细胞周期调节的机制。1998年初，我们发现人胎肾细胞周期静止与足细胞分化密切相关。细胞周期阻滞与细胞周期抑制剂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，我们在人类活检材料中发现CKIs在月牙状细胞和局灶性肾小球硬化的细胞病变中低表达。这些增殖细胞实际上表达了细胞角蛋白，表明了壁上皮细胞的表型。因此，PECs补偿足细胞损失是一种促进肾小球硬化的实际病理。1999年的第二年，我们进行了体外研究。后肾器官培养显示p27表达上调，而p57表达上调与足细胞分化一致。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，我们观察了白细胞介素-4在足细胞培养中的作用。我们发现il - 4刺激足细胞细胞系形成圆顶状。因此，IL-4可能改变细胞附着系统，即病灶接触。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被激活并分化。胎儿肾脏和后肾培养系统在毛细血管环期显示足细胞发光。这种杂交启动子的兴奋剂需要进一步研究。

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.