PhD Student Leiden University Medical Center Leiden University Medical Center, Netherlands
Abstract: Human induced pluripotent stem cell (iPSC)-derived kidney organoids (KORs) show great promise as viable alternatives for transplantation in regenerative medicine. We previously demonstrated that the transplantation of these KORs into the coelom of chicken embryos triggers both glomerular vascularization and podocyte maturation, suggesting a role for endothelial cell (EC)-derived factors (angiocrine factor) in glomerulogenesis. In this study, we leveraged scRNA-seq data from untransplanted and transplanted KORs, as well as human fetal kidneys (hFKs), to pinpoint angiocrine factors and receptors involved in this process. We identified specific ligand-receptor pairs between developing (glomerular) ECs and podocytes from transplanted KORs and hFKs using scRNA-seq data. Ligands whose signaling was active during podocyte maturation in transplanted KOR or hFKs were further analyzed, yielding TGFB1/TGFBR3 as the top ligand/receptor pair, along with possible downstream target genes in podocytes. Furthermore, pseudotime reconstruction of podocyte differentiation in KORs and hFKs revealed TGFBR3 upregulation at the latest stage of podocyte development, further supporting its potential role as the key angiocrine factor receptor required for advanced glomerular maturation. To explore this further, we generated an iPSC line with a podocyte-specific knockout of TGFBR3 when differentiated to KORs. We then developed an in vitro co-culture system combining KORs with blood vessel organoids. By comparing podocyte-specific TGFBR3 knockout KORs with unmodified controls, we aim to investigate the impact of TGFBR3 loss on vascularization and glomerular maturation. This research holds the potential to significantly advance our understanding of glomerular vascularization and podocyte maturation in KORs in vivo and translate these findings to in vitro applications.
Funding Source: The Novo Nordisk Foundation Center for Stem Cell Medicine (reNEW, supported by Novo Nordisk Foundation grants (NNF21CC0073729)).
