Project description:During kidney development segmented epithelia of the nephron derive from progenitor cells in the metanephric mesenchyme after induction by secreted molecules from the ureteric bud. We have identified three distinct inductive activities from a ureteric bud cell line. These include leukemia inhibitory factor (LIF), neutrophil gelatinase-associated lipocalin (NGAL) and an active fraction currently referred to as ANX. Each of these activities induces segmented nephron epithelia in isolated rat metanephric mesenchyme over a time period of 7 days. This study was designed to characterize the temporal sequence of gene expression in the course of the conversion process induced by each of the distinct inducers. Keywords: time course
Project description:During kidney development segmented epithelia of the nephron derive from progenitor cells in the metanephric mesenchyme after induction by secreted molecules from the ureteric bud. We have identified three distinct inductive activities from a ureteric bud cell line. These include leukemia inhibitory factor (LIF), neutrophil gelatinase-associated lipocalin (NGAL) and an active fraction currently referred to as ANX. Each of these activities induces segmented nephron epithelia in isolated rat metanephric mesenchyme over a time period of 7 days. This study was designed to characterize the temporal sequence of gene expression in the course of the conversion process induced by each of the distinct inducers. Experiment Overall Design: Metanephric mesenchymes were microdissected from rat E13.5 embryos. Mesenchymes were cultured on transwells in the presence of either LIF, NGAL or the ANX fraction and RNA was harvested after 1, 2, 3, 4, 5, and 7 days for RNA extraction. Freshly dissected mesenchymes and mesenchymes cultured in the absence of inducers for 1 and 2 days, respectively, served as controls. Each condition was analyzed in duplicate (biological replicates). Biotinylated cRNA was prepared and hybridized to Affymetrix Rat Genome 230 2.0 Microarrays. Expression values were obtained by robust multichip analysis.
Project description:BACKGROUND: Lim1 is a homeobox gene that is essential for nephrogenesis. During metanephric kidney development, Lim1 is expressed in the nephric duct, ureteric buds, and the induced metanephric mesenchyme. Conditional ablation of Lim1 in the metanephric mesenchyme blocks the formation of nephrons at the nephric vesicle stage, leading to the production of small, non-functional kidneys that lack nephrons. METHODS: In the present study, we used Affymetrix probe arrays to screen for nephron-specific genes by comparing the expression profiles of control and Lim1 conditional mutant kidneys. Kidneys from two developmental stages, embryonic day 14.5 (E14.5) and 18.5 (E18.5), were examined. RESULTS: Comparison of E18.5 kidney expression profiles generated a list of 465 nephron-specific gene candidates that showed a more than 2-fold increase in their expression level in control kidney versus the Lim1 conditional mutant kidney. Computational analysis confirmed that this screen enriched for kidney-specific genes. Furthermore, at least twenty-eight of the top fifty (56%) candidates (or their vertebrate orthologs) were previously reported to have a nephron-specific expression pattern. Our analysis of E14.5 expression data yielded 41 candidate genes that are up-regulated in the control kidneys compared to the conditional mutants. Three of them are related to the Notch signaling pathway that is known to be important in cell fate determination and nephron patterning. CONCLUSIONS: Therefore, we demonstrate that Lim1 conditional mutant kidneys serve as a novel tissue source for comprehensive expression studies and provide a means to identify nephron-specific genes. Keywords: tissue specificity, time course, development, kidney, metanephric mesenchyme, nephron, Lim1, knockout mice, conditional knockout
Project description:Understanding processes how the early stage kidney precursor gives rise to metanephric mesenchyme, which is a committed progenitor cells of adult kidney is important for the regeneration of kidney in vitro. The combination of fluorescent activated cell sorting (FACS) plus microarray analysis offers a powerful, efficient and effective method for the creation of global gene expression profiles of the developing kidney precursors. Those gene expression data provides insights into not only the stage specific marker genes but also the signals working in each population, which should be informative for the directed differentiation of pluripotent stem cells in vitro. Osr1-GFP knock-in mice were used to isolate kidney precursor cells from embryos at E8.5, E9.5 and E11.5. At E9.5 and E11.5 embryos, to identify the differences between nephron progenitors and surrounding mesenchyme, nephron progenitor populations were further enriched by gating Osr1-GFP positive Integrin alpha8 positive Pdgfr alpha negative population and compared with Osr1-GFP positive cells other than that gate. RNA was isolated from cells and the gene expression profiles were determined by microarrays.
Project description:E11.5 metanephric mesenchyme and ureteric bud were dissected from the E11.5 kidney rudiment using fine manual microdissection (ureteric bud only) or both fine manual microdissection and laser capture microdissection (metanephric mesenchyme) to define the gene expression profiles of these structures. Additionally, HoxA11, HoxD11 compound null E11.5 metanephric mesenchyme was obtained through laser capture microdissection allowing analysis of possible Hox targets in kidney development. Targets from multiple biological replicates of each were generated and the expression profiles were determined using Affymetrix MOE430_v2 arrays. Keywords: embryonic metanephric kidney, kidney development, Hoxa11, Hoxd11, compound null targeted mice
Project description:In this study we identify molecules with highly restricted expression patterns during the initial stages of metanephric development, when the ureteric bud has entered the metanephric mesenchyme and initiated branching morphogenesis. Using the Affymetrix Mouse Genome 430 2.0 Array, we compare gene expression patterns in ureteric bud tips, stalks and metanephric mesenchymes from mouse E12.5 embryos. To identify conserved molecular pathways, we also analyze transcriptional profiles in rat E13.5 ureteric buds and metanephric mesenchymes using the Affymetrix Rat Genome U34 Set. Taken together, these data sets help to identify conserved and highly localized transcripts in the metanephric kidney. Keywords = Mus musculus Keywords = Rattus norvegicus Keywords = metanephric mesenchyme Keywords = ureteric bud Keywords = ureteric bud tips Keywords = ureteric bud stalks Keywords = molecular screen for spatially restricted transcripts Keywords: other
Project description:E11.5 metanephric mesenchyme and ureteric bud were dissected from the E11.5 kidney rudiment using fine manual microdissection (ureteric bud only) or both fine manual microdissection and laser capture microdissection (metanephric mesenchyme) to define the gene expression profiles of these structures. Additionally, HoxA11, HoxD11 compound null E11.5 metanephric mesenchyme was obtained through laser capture microdissection allowing analysis of possible Hox targets in kidney development. Targets from multiple biological replicates of each were generated and the expression profiles were determined using Affymetrix MOE430_v2 arrays. Using microdissection techniques, ureteric bud and metanephric mesenchyme were dissected from E11.5 kidney rudiments allowing the identificated genes specifically regulated in either structure. In addition, Hoxa11, Hoxd11 compound null E11.5 metanephric mesenchyme were normalized to wild type embryonic controls allowing the identification of potential Hox targets in normal kidney development. Each structure/genotype were represented in biological (seperate embryo) replicate.
Project description:We aimed to define epithelial-specific genes in the kidney. In the developing mouse kidney at E12.5 epithelial cells are restricted to the ureteric bud, while mesenchymal cells surrounding the ureteric bud are non-epithelial. The mouse renal epithelial cell line mIMCD-3 was used to represent kidney epithelia in vitro. Gene expression was analyzed using Affymetrix microarrays in ureteric bud stalks, ureteric bud tips, and mIMCD-3 cells and compared to metanephric mesenchyme.