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

肾近端小管S3段对缺血损伤非常敏感，但具有显著的结构和功能修复能力。在S3片段特异性启动子Gsl5的控制下，采用“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（DT）受体的转基因小鼠系。给这些转基因小鼠注射DT，以剂量依赖的方式引起S3节细胞的选择性消融。这些结果表明，该转基因小鼠在给药后可发生由S3节特异性损伤引起的急性肾损伤（AKI）。该转基因系为揭示AKI的机制及其快速恢复提供了一个极好的模型。我们尝试建立胚胎干细胞和诱导能干细胞向肾小管细胞分化的方法。在胚胎干细胞中，激活素通过上皮标志物Ksp-Cadherin的表达来促进胚胎干细胞向小管细胞的分化。激活素也促进了iPS细胞向管状细胞的分化，尽管其增强作用低于胚胎干细胞。我们制备了针对Ksp-Cadherin细胞外结构域的单克隆抗体。抗体流式细胞术纯化ksp阳性细胞，在基质上形成管状结构。建立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.