Utilising a three-dimensional system to understand nephrogenesis

Monolayer culture of kidney cells and ex vivo and in vitro experiments using model organisms are commonly used in studies of renal development, yet it is unclear how these correlate with human kidney development in vivo. Recent research aimed at engineering new kidneys from dissociated renal cells demonstrates that it is feasible to generate multiple nephron segments, resulting in a three-dimensional, miniature kidney like structure, albeit with poor overall structural organisation than a normal kidney. This has been done predominantly using cells obtained directly from mouse embryos within the first two days of kidney formation, and it is not thought to be possible to use older murine organs. In theory, it should also be possible to generate neo-kidneys using human renal progenitor cells from fetal kidneys; however, these can never be obtained early enough to correspond to the mouse stages that are normally used. Here, I not only show that dissociated renal cells from older embryonic mice are able to generate multiple nephron segments, but also that human fetal kidney cells are able to produce typical nephron elements. Dissociated renal cells from older embryonic mice not only generate structural elements resembling normal kidney tubules and glomeruli but they also have anion uptake capacity as might be seen in vivo, illustrating functional capacity. Human fetal kidney cells generated from gestational ages between 10 and 16 weeks were additionally able to produce apparently typical nephron elements. Some inter-species differences were observed in the morphology of the ureteric buds, with fewer branches found in the human compared to the mouse, along with an obvious difference in the expression pattern of CALB1+ cells. However, the human cell-derived neo-kidneys expressed functional anion and cation transporters. This thesis demonstrates that organotypic renal structures with functional ion transporters can be generated from human fetal kidney cells. This provides us with a novel approach to understand and examine nephrogenesis and, essentially, to model kidney disease from a human perspective.