Growth and differentiation of human induced pluripotent stem cell (hiPSC) derived kidney organoids using fully synthetic peptide hydrogels

Abstract

Human induced pluripotent stem cell (hiPSC)‐derived kidney organoids have prospective applications ranging from basic disease modelling to personalised medicine. However, there remains a necessity to refine the biophysical and biochemical parameters that govern kidney organoid formation. Differentiation within fully‐controllable and physiologically relevant 3D growth environments will be critical to improving organoid reproducibility and maturation. Here, we matured hiPSC‐derived kidney organoids within fully synthetic self‐assembling peptide hydrogels (SAPHs) of variable stiffness (storage modulus, G′). The resulting organoids contained complex structures comparable to those differentiated within the animal‐derived matrix, Matrigel. Single‐cell RNA sequencing (scRNA‐seq) was then used to compare organoids matured within SAPHs to those grown within Matrigel or at the air‐liquid interface. A total of 13,179 cells were analysed, revealing 14 distinct clusters. Organoid compositional analysis revealed a larger proportion of nephron cell types within Transwell‐derived organoids, while SAPH derived organoids were enriched for stromal‐associated cell populations. Notably, differentiation within a higher G’ SAPH generated podocytes with more mature gene expression profiles. Additionally, maturation within a 3D microenvironment significantly reduced the derivation of offtarget cell types, which are a known limitation of current kidney organoid protocols. This work demonstrates the utility of synthetic peptide‐based hydrogels with a defined stiffness, as a minimally complex microenvironment for the selected differentiation of kidney organoids.