Reassembly of human kidney organoids after dissociation

Human induced pluripotent stem cell (iPSC)-derived kidney organoids have emerged as a valuable model for studying kidney development and disease. Phenotypically, these organoids resemble kidneys of gestational week 12. Embryonic kidneys have the capacity to reassemble after dissociation, which offers the possibility to study the effect of introducing additional cell types or gene expression modification through transfection of dissociated organoids before reassembly. We examined whether human iPSC-derived kidney organoids share the property of embryonic kidneys to reassemble after dissociation. This would open new research avenues with human kidney organoids.

Human iPSC-derived kidney organoids were dissociated into single cells by TrypLE Select and reaggregated by centrifugation. Organoids were collected 4 and 7 days after reaggregation and immunostaining was performed to assess structural organization. Restoration of endocrine activity was assessed by measurement of renin production. As a proof of principle, dissociated organoids were transfected with a GFP expressing plasmid, and expression was monitored in reaggregated organoids.

Kidney organoids displayed the capacity to reassemble proximal and distal tubular structures, demonstrated by reappearance of Villin-1+ and E-cadherin+ structures. Podocalyxin (PODXL)+ glomerular structures reappeared sparsely after dissociation. Reassembled organoids responded to forskolin with renin secretion, albeit at a lower level than non-dissociated organoids. Dissociated organoids that were transfected with a GFP plasmid at the cell suspension stage showed robust GFP expression after reassembly.

Human kidney organoids partially reassemble after dissociation. Dissociation and reassembly of kidney organoids offers a novel tool for kidney organoid research that allows the introduction of exogenous cell types or transfection of kidney organoid cells.