Generation of human-pig chimeric renal organoids using iPSC technology

The potential of using porcine organs and human induced pluripotent stem cell (iPSC)-derived organoids as alternative organs for human transplantation has garnered growing attention. However, both approaches still face technological challenges. Interspecies chimeric organ production using human iPSCs is expected to be another promising approach that addresses the challenges associated with organ production. Our research group successfully generated human-mouse chimeric renal organoids by utilizing human iPSC-derived nephron progenitor cells (NPCs) and fetal mouse kidneys. However, the current technology has limited engraftment and development capabilities for human NPCs, and there have been no reports of generating interspecies chimeric renal organoids in larger animals, limited only to rodents. Therefore, in this study, we embarked on the production of human-pig chimeric renal organoids using the pig kidney, which is considered the most promising source of organs for interspecies transplantation to humans. To construct a human-pig chimeric renal organoid culture system, we first modified the existing human-mouse chimeric renal organoid culture system and developed a method that enables the survival and continued renal development of both species. This method was found to be applicable to porcine fetal kidney cells, and ultimately, we successfully produced human-pig chimeric renal organoids. Furthermore, this culture method can also be applied to the generation of human interspecies chimeric kidneys for future clinical applications. The findings of this study serve as a foundational technology that will greatly accelerate future research in humanized pig kidney production for clinical purposes, and are also expected to be used as an evaluation technique to ensure the quality of human NPCs for xenotransplantation. ### Competing Interest Statement S.Y., K.M., S.K., and T.Y. declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. K.F., K.S., T.K., A.I., and M.I. are the employees of Sumitomo Pharma Co., Ltd. E.K. has received a research fund from Sumitomo Pharma Co., Ltd. as a result of the Collaborative Research Agreement between The Jikei University School of Medicine and Sumitomo Pharma Co., Ltd. E.K. is the Chief Information Officer of Kobayashi Regenerative Research Institute, LLC. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results.