Human iPSC-derived nephron progenitor cells treat AKI and CKD in mouse models

The number of patients requiring dialysis therapy continues to increase worldwide due to the lack of effective treatments for chronic kidney disease (CKD). Furthermore, no curative treatments for acute kidney injury (AKI) have been established. The therapeutic effects of human induced pluripotent stem cell-derived nephron progenitor cells (hiPSC-NPCs) on AKI have been reported in mice but not clinically confirmed. There are also no reports examining the therapeutic potential of hiPSC-NPCs on CKD. Although large numbers of uniform hiPSC-NPCs are required for cell therapies for AKI and CKD, effective expansion cultures remain to be developed. Here, we established a CFY (CHIR99021, FGF9, Y-27632) medium for cell culture that enables more than 100-fold proliferation of hiPSC-NPCs from multiple hiPSC lines in two passages. We demonstrated that hiPSC-NPCs expanded by CFY or their conditioned medium alone attenuate kidney injury and improve survival in cisplatin-induced AKI mice. We also observed that hiPSC-NPCs prevented kidney functional decline, interstitial fibrosis, and senescence in aristolochic acid-induced CKD mice. In addition, we discovered c-MET as a specific cell surface marker for hiPSC-NPCs and confirmed that purified c-MET+ hiPSC-NPCs have therapeutic effects on AKI and CKD. Furthermore, we found that hiPSC-NPCs exerted their therapeutic effects in AKI and CKD mice by secreting vascular endothelial growth factor A (VEGF-A). Together, expanded hiPSC-NPCs are useful cell therapies for AKI and CKD, and may open new avenues for treating kidney diseases. Overall design: RNA-seq profiling of bulk cells and cells purified with OSR1 and SIX2 (OSR1+SIX2, OSR1+SIX2-, OSR1-SIX2-) at day11 of nephron progenitor cell differentiation.全球范围内，由于慢性肾脏病（chronic kidney disease, CKD）缺乏有效治疗手段，需要接受透析治疗的患者数量持续攀升。此外，急性肾损伤（acute kidney injury, AKI）目前仍未确立治愈性疗法。人诱导多能干细胞来源的肾单位祖细胞（human induced pluripotent stem cell-derived nephron progenitor cells, hiPSC-NPCs）对AKI的治疗效果已在小鼠模型中得到报道，但尚未获得临床证实；目前也尚无关于hiPSC-NPCs对CKD治疗潜力的相关研究报告。 尽管AKI与CKD的细胞疗法需要大量均质的hiPSC-NPCs，但高效的扩增培养体系仍有待开发。本研究构建了一种名为CFY（CHIR99021、FGF9、Y-27632）的细胞培养基，可在两次传代过程中实现多株人诱导多能干细胞系来源的hiPSC-NPCs超过100倍的增殖。 研究证实，经CFY培养基扩增的hiPSC-NPCs，或其单独的条件培养基，可减轻顺铂诱导的AKI小鼠的肾损伤并提升其存活率。同时，本研究还观察到，hiPSC-NPCs可阻止马兜铃酸诱导的CKD小鼠出现肾功能下降、间质纤维化及细胞衰老。此外，本研究发现c-MET可作为hiPSC-NPCs的特异性细胞表面标志物，并证实纯化得到的c-MET阳性hiPSC-NPCs对AKI与CKD均具有治疗效果。进一步研究发现，hiPSC-NPCs可通过分泌血管内皮生长因子A（vascular endothelial growth factor A, VEGF-A）来发挥对AKI与CKD小鼠的治疗作用。 综上，扩增后的hiPSC-NPCs可作为AKI与CKD的有效细胞疗法，有望为肾脏疾病的治疗开辟全新途径。 总体实验设计：对肾单位祖细胞分化第11天的批量细胞，以及经OSR1和SIX2纯化的细胞（OSR1+SIX2+、OSR1+SIX2-、OSR1-SIX2-）进行RNA-seq转录组分析。