Osafune Kenji, Takasato Minoru, Kispert Andreas, Asashima Makoto, Nishinakamura Ryuichi
Division of Stem Cell Regulation, The Institute of Medical Science, The University of Tokyo, Tokyo 108-8639, Japan.
Development. 2006 Jan;133(1):151-61. doi: 10.1242/dev.02174. Epub 2005 Nov 30.
Renal stem or progenitor cells with a multilineage differentiation potential remain to be isolated, and the differentiation mechanism of these cell types in kidney development or regeneration processes is unknown. In an attempt to resolve this issue, we set up an in vitro culture system using NIH3T3 cells stably expressing Wnt4 (3T3Wnt4) as a feeder layer, in which a single renal progenitor in the metanephric mesenchyme forms colonies consisting of several types of epithelial cells that exist in glomeruli and renal tubules. We found that only cells strongly expressing Sall1 (Sall1-GFP(high) cells), a zinc-finger nuclear factor essential for kidney development, form colonies, and that they reconstitute a three-dimensional kidney structure in an organ culture setting. We also found that Rac- and JNK-dependent planar cell polarity (PCP) pathways downstream of Wnt4 positively regulate the colony size, and that the JNK pathway is also involved in mesenchymal-to-epithelial transformation of colony-forming progenitors. Thus our colony-forming assay, which identifies multipotent progenitors in the embryonic mouse kidney, can be used for examining mechanisms of renal progenitor differentiation.
具有多谱系分化潜能的肾干细胞或祖细胞仍有待分离，并且这些细胞类型在肾脏发育或再生过程中的分化机制尚不清楚。为了解决这个问题，我们建立了一种体外培养系统，使用稳定表达Wnt4的NIH3T3细胞（3T3Wnt4）作为饲养层，在该系统中，后肾间充质中的单个肾祖细胞形成由肾小球和肾小管中存在的几种上皮细胞组成的集落。我们发现，只有强烈表达Sall1（Sall1-GFP（高）细胞）的细胞才能形成集落，Sall1是一种对肾脏发育至关重要的锌指核因子，并且它们在器官培养环境中重构三维肾脏结构。我们还发现，Wnt4下游的Rac和JNK依赖性平面细胞极性（PCP）途径正向调节集落大小，并且JNK途径也参与形成集落的祖细胞的间充质-上皮转化。因此，我们用于鉴定胚胎小鼠肾脏中多能祖细胞的集落形成试验可用于研究肾祖细胞分化的机制。
