Project description:A platform for generating expandable, branching and gene-editable ureteric bud organoid from primary mouse and human ureteric bud progenitor cells and human pluripotent stem cells, and its maturation into collecting duct organoid.
Project description:Kidney development depends critically on proper ureteric bud branching giving rise to the entire collecting duct system. The transcription factor HNF1B is required for the early steps of ureteric bud branching. Yet, the molecular and cellular events regulated by HNF1B are poorly understood. We report that specific removal of Hnf1b from the ureteric bud leads to defective cell-cell contacts and apico-basal polarity during the early branching events. High resolution ex vivo imaging combined with a membranous fluorescent reporter strategy show decreased mutant cell-rearrangements during mitosis-associated cell dispersal and severe epithelial disorganisation. Molecular analysis reveals downregulation of Gdnf-Ret pathway components and suggests that HNF1B acts both upstream and downstream of Ret-signaling by directly regulating Gfrα1 and Etv5. Subsequently, Hnf1b-deletion leads to massively mispatterned ureteric tree network, defective collecting duct differentiation and disrupted tissue architecture leading to cystogenesis. Consistently, mRNA-seq analysis performed from E15.5 control and mutant kidneys shows that the most impacted genes encode intrinsic cell-membrane components with transporter activity. Our study uncovers a fundamental and recurrring role of HNF1B in epithelial organization during early ureteric bud branching and further patterning and differentiation of the collecting duct system. Article submitted to Development. Authors: Audrey Desgrange, Claire Heliot,Ilya Skovorodkin, Saad U. Akram, Janne Heikkilä, Veli-Pekka Ronkainen, Ilkka Miinalainen I., Seppo J. Vainio and Silvia Cereghini
Project description:Here, establishing expansion cultures of hiPSC-derived ureteric bud tip cells, an embryonic precursor that gives rise to collecting ducts, we succeeded in advancing the developmental stage of collecting duct organoids and showed that all collecting duct organoids derived from PKD1-/- hiPSCs spontaneously develop multiple cysts, clarifying the initiation mechanisms of cystogenesis.
Project description:We performed directed differentiation of human pluripotent stem cells (hPSCs) into ureteric bud (UB) organoids and performed single cell transcriptomics to analyze different stages of development. At day 7, the spheroids exhibited a nephric duct (ND) signature, and we identified there is also a population of stromal progenitor cells within the cluster. At day 18, the organoids comprise more differentiated collecting duct (CD) cell types including principal cells.
Project description:Ureteric bud (UB) is the embryonic kidney progenitor tissue that gives rise to the collecting duct and lower urinary tract. UB-like structures generated from human pluripotent stem cells by previously reported methods show limited developmental ability and limited branching. Here we report a new method to generate UB organoids that possess epithelial polarity and tubular lumen and repeat branching morphogenesis. We also succeeded in monitoring UB tip cells by utilizing the ability of tip cells to uptake very-low-density lipoprotein, cryopreserving UB progenitor cells and expanding UB tip cells that can reconstitute the organoids and differentiate into collecting duct progenitors. Moreover, we successfully reproduced some phenotypes of multicystic dysplastic kidney (MCDK) using the UB organoids. These methods will help elucidate the developmental mechanisms of UB branching and develop a selective differentiation method for collecting duct cells, contributing to the creation of disease models for congenital renal abnormalities.
Project description:Ureteric bud (UB) is the embryonic kidney progenitor tissue that gives rise to the collecting duct and lower urinary tract. UB-like structures generated from human pluripotent stem cells by previously reported methods show limited developmental ability and limited branching. Here we report a new method to generate UB organoids that possess epithelial polarity and tubular lumen and repeat branching morphogenesis. We also succeeded in monitoring UB tip cells by utilizing the ability of tip cells to uptake very-low-density lipoprotein, cryopreserving UB progenitor cells and expanding UB tip cells that can reconstitute the organoids and differentiate into collecting duct progenitors. Moreover, we successfully reproduced some phenotypes of multicystic dysplastic kidney (MCDK) using the UB organoids. These methods will help elucidate the developmental mechanisms of UB branching and develop a selective differentiation method for collecting duct cells, contributing to the creation of disease models for congenital renal abnormalities.
Project description:During development, distinct progenitors contribute to the nephrons versus the ureteric epithelium of the kidney. Indeed, previous pluripotent stem cell-derived models of kidney tissue either contain nephrons or pattern specifically to the ureteric epithelium. By reanalysing the transcriptional distinction between distal nephron and ureteric epithelium in human fetal kidney, we show here that while existing nephron-containing kidney organoids contain distal nephron epithelium and no ureteric epithelium, this distal nephron segment alone displays significant in vitro plasticity and can adopt a ureteric epithelial tip identity when isolated and cultured in defined conditions. “Induced” ureteric epithelium cultures can be cryopreserved, serially passaged without loss of identity and transitioned towards a collecting duct fate. Indeed, cultures harbouring loss-of-function mutations in PKHD1 recapitulate the cystic phenotype associated with autosomal recessive polycystic kidney disease.
Project description:Grb2 is a small SH2-SH3 adaptor molecule that interacts with activated tyrosine kinase receptors (RTKs), providing a crucial link towards downstream activation of pro-proliferative and pro-survival ERK and Akt signaling pathways. Ret and FGFR2, two RTKs that interact with Grb2, play important roles in ureteric branching and the proper establishment of the renal collecting duct system, but it is unclear whether Grb2 is required in this process. In this study, we selectively ablated a conditional floxed allele of the Grb2 gene within the ureteric epithelial lineage in mice and demonstrate that Grb2 signaling is essentially required for proper collecting duct development. Ureteric Grb2 deficiency results in perinatal lethality and severe renal hypodysplasia closely reminiscent of the rudimentary kidney phenotypes observed in Ret-null mutant mice. Grb2 loss attenuates ERK and Akt activation in the ureteric epithelia resulting in pronounced impairment of ureteric branching. Gene expression analysis reveals that Grb2 deficiency results in defective induction of genes implicated in both ureteric branching and reciprocal mesenchymal metanephric induction. Our findings therefore strongly indicate that Grb2 is a physiologically-relevant major RTK signaling relay partner that promotes renal branching morphogenesis and the proper development of the collecting duct system and the urogenital tract. Microarray was used to profile and compare the transcriptomes of developing kidneys of E14.5 Grb2 conditional knockout (ureteric-bud specific) and wild-type embryos
Project description:We established the expansion culture of human iPSC-derived ureteric bud tip cells (UBTCs), an embryonic precursor that give rise to collecting ducts (CDs), and succeeded in advancing the developmental stage of CD organoids. We used single cell RNA-sequencing (scRNA-seq) to dissect cell types in CD organoids.