While nephron progenitors are believed to originate from the intermediate mesoderm that expresses a transcription factor Osr1, we unexpectedly find that nephron progenitors are derived from posteriorly

located T (Brachyury)-positive population at the post-gastrulation stage, which is developmentally distinct from Osr1-positive ureteric bud precursors. We also identify phasic Wnt stimulation and stage-specific growth factor addition as molecular cues that promote the development of T-positive precursors into the nephron progenitors. We then use this information to derive nephron progenitors, via the newly identified T-positive precursors, from mouse embryonic stem cells and human induced Rapamycin pluripotent stem cells. Upon Wnt4 stimulation, the induced nephron progenitors readily reconstitute the three-dimensional structures of the kidney in vitro, including glomeruli with podocytes and renal tubules with clear lumina. Furthermore, mouse glomeruli are efficiently vascularized upon transplantation, because glomerular podocytes express vasculogenic factors including VEGF. Thus, by redefining the developmental origin of

nephron progenitors, we have revealed the molecular cascades of kidney specification in vivo and succeeded in generating the three-dimensional nephrons in vitro from pluripotent stem cells both in mice see more and humans. LITTLE MH1, TAKASATO M1, ER P1, BECROFT M1, VANSLAMBROUCK J1, STANLEY E2, ELEFANTY A1,2 1Institute for Molecular Bioscience, The University of Queensland, Australia; 2Murdoch

Children’s Research Institute, Parkville, Australia The use of pluripotent stem cells for the generation of distinct adult tissue types is a major area of promise for the field of regenerative medicine. With the prevalence of end-stage renal disease rising 8% per annum globally, this is an approach of particular interest in the area of kidney. CYTH4 However, the kidney is comprised of a large number of functionally distinct cell types in the adult organ. In contrast, the embryonic organ is formed from a smaller number of progenitor populations. The kidney is a mesodermal organ that differentiates from the intermediate mesoderm (IM), itself is derived from the posterior primitive streak (PPS). The IM gives rise to both a ureteric bud (UB) and an adjacent IM-derived metanephric mesenchyme (MM). Reciprocal signaling between these two cell types results in a branched epithelial ureteric tree, which forms the collecting duct, and the formation of the nephron via a mesenchyme to epithelial transition of the MM. This reciprocal signaling involves the production of secreted growth factor signals from the MM that promote UB branching and signals from the UB to maintain a self-renewing population of nephron-forming mesenchyme as well as to initiate nephron formation. The goal of our project was to recapitulate these developmental processes to as to direct the differentiation of pluripotent stem cells towards kidney in a stepwise manner towards normal kidney development.