Human kidney organoids for modeling the development of different diseases

The increasing incidence of kidney diseases has highlighted the need for in vitro experimental models to mimic disease development and to test new therapeutic approaches. Traditional two-dimensional in vitro experimental models are not fully able to recapitulate renal diseases. Instead, kidney organoids represent three-dimensional models that better mimic the human organ from both structural and functional points of view. Human pluripotent stem cells (PSCs), both embryonic and induced, are ideal sources for generating renal organoids. These organoids contain all renal cell types and the protocols to differentiate PSCs into renal organoids consist of three different stages that recapitulate embryonic development: mesodermal induction, nephron progenitor formation, and nephron differentiation. Recently it has been establish a renal organoid model where collecting ducts are also present. In this case, the presence of ureteric bud progenitor cells is essential. Renal organoids are particularly useful for studying genetic diseases, by introducing the specific mutations in PSCs by genome editing or generating organoids from patient-derived PSCs. Moreover, renal organoids represent promising models in toxicology studies and testing new therapeutic approaches. Renal organoids can be established also from adult stem cells. This type of organoid, named tubuloid, is composed only of epithelial cells and recapitulates the tissue repair process. The tubuloids can be generated from adult stem or progenitor cells, obtained from renal biopsies or urine, and are promising in vitro models for studying tubular functions, diseases, and regeneration. Tubuloids can be derived from patients and permit the study of genetic diseases, performing personalized drug screening and modeling renal pathologies.