Mechanism of regeneration of renal tubular cells and differentiation from ES and iPS cells to renal tubular cells

肾近端小管的S3段对缺血损伤高度敏感，但具有显著的修复结构和功能的能力。应用S3片段特异性启动子Gsl5控制下的“毒素受体介导的细胞敲除”方法，建立了仅在S3片段表达人白喉毒素受体的转基因小鼠系。这些转基因小鼠给予DT后，S3节段细胞被选择性消融，且呈剂量依赖关系。这些结果表明，该转基因小鼠在注射DT后可出现S3片段特异性损伤所致的急性肾损伤(AKI)。该转基因系为揭示AKI的发病机制及其快速恢复提供了良好的模型。我们试图建立ES细胞和iPS细胞向肾小管细胞分化的方法。在ES细胞中，激活素促进了ES细胞向管状细胞的分化，这从上皮标记物KSP-钙粘附素的表达来看。激活素也促进了iPS细胞向管状细胞的分化，尽管这种促进作用低于ES细胞。我们制备了抗人KSP-钙粘附素胞外区的单抗。用该抗体进行流式细胞仪检测，纯化的KSP阳性细胞在Matrigel表面形成管状结构。建立了ES细胞和iPS细胞向肾小管细胞分化的方法。

The S3 segment of the kidney proximal tubule is highly susceptible to ischemia insults but has a remarkable capacity to repair its structure and function. By applying the "toxin receptor mediated cell knockout" method under the control of the S3 segment-specific promoter Gsl5, we established a transgenic mouse line expressing the human diphtheria toxin(DT) receptor only in the S3 segment. The administration of DT to these transgenic mice caused the selective ablation of S3 segment cells in a dose-dependent manner. These results indicate that this transgenic mouse can suffer acute kidney injury(AKI) caused by S3 segment-specific damage after DT administration. This transgenic line offers an excellent model to uncover the mechanisms of AKI and its rapid recovery.We tried to establish differentiation method of ES cells and iPS cells into renal tubular cells. In ES cells, Activin enhanced the differentiation of ES cells to tubular cells, judging by expression of Ksp-Cadherin, the epithelial marker. Activin also enhanced the differentiation of iPS cells to tubular cells, although the enhancement was lower than in ES cells. We generated monoclonal antibody against the extracellular domain of Ksp-Cadherin. Flow cytometry using the antibody purified the Ksp-positive cells, which formed tubular structure on Matrigel. We established the differentiation method of ES and iPS cells into renal tubular cells.