Assessment of hiPSC-derived kidney organoids from cryopreserved progenitors using MALDI-MSI

Induced pluripotent stem cell (iPSC) derived kidney organoids are three-dimensional aggregates that self-organize in a permissive environment, and exhibit structural similarities to the adult kidney. The potential application of these tissues in regenerative medicine as a clinical therapy is currently investigated. Before such therapies can be realized, comprehensive assessment of the cell types present in kidney organoids is required. We recently proposed MALDI-MSI (Matrix-Assisted Laser Desorption Ionization - Mass spectrometry imaging) as a technology for evaluating cellular composition of intact tissue samples. This approach removes the need for tissue dissociation, thereby preserving architecture and maintaining specific cell populations. Consequently, this technology could be explored for in depth characterization of cell composition in cultured kidney organoids. In this study, we cryopreserved iPSC-derived kidney progenitors at day 7 of differentiation and demonstrate that their differentiation could be successfully resumed after thawing. We then applied MALDI-MSI to assess quality of the kidney organoids and evaluated the cell types present by analyzing their lipid profiles. In parallel, we used immunohistochemistry to identify specific cell types, including glomeruli as well as proximal and distal tubular structures. Importantly, lipidomics profiling using MALDI-MSI provided a more comprehensive cellular overview of tissue composition, allowing us to directly compare cryopreserved and non-cryopreserved kidney organoids. In conclusion, we suggest MALDI-MSI as a platform that can be used for in depth cell type analysis of kidney organoid cultures.