Single-cell RNA sequencing and kidney organoid differentiation.

Since 2015, Japanese researchers have made great progress in developing a method to differentiate human pluripotent stem cells (hPSCs) into kidney organoids. Protocols have been established to produce increasingly complex three-dimensional (3D) structures, which are used as a human kidney disease model and adapted for high-throughput screening. During this period, single-cell RNA sequencing (scRNA-seq) technology was developed to perform a comprehensive analysis at the single-cell level. We have performed a comprehensive analysis using scRNA-seq to define how kidney organoids can be applied to understand kidney development and pathology. The structure of kidney organoids is complex and contains many cell types of varying maturity. Since only a few proteins and mRNAs can be identified by immunostaining and other techniques, we performed scRNA-seq, which is an unbiased technology that can comprehensively categorize all cell types present in organoids. The aim of this study is to review the problems of kidney organoids based on scRNA-seq and the efforts to address the problems and predict future applications with this powerful technique.