Project description:The Wnt/β-catenin signaling pathway is crucial for the development of variety of organs including the mammary gland. However, the precise role of Wnt/β-catenin signaling during embryonic mammary gland morphogenesis is still poorly understood. Here, we used an epithelial gain-of-function β-catenin mouse model to study the role of Wnt/β-catenin signaling in embryonic mammary gland development and profiled the transcriptomes of E13.5 and E16.5 control and mutant mammary epithelia.
Project description:Both FGF and WNT pathways play important roles in embryonic development, stem cell self-renewal and are frequently deregulated in breast cancer. To study the cooperation between FGF and WNT signaling, we have generated a mouse model, MMTV-WNT1/MMTV-iFGFR1 (WNT/iR1), in which we could chemically overactivate iFGFR1 in a ligand-independent manner.
Project description:Upon implantation, the naive pluripotent epiblast of the mouse blastocyst generates a rosette, undergoes lumenogenesis and forms the primed pluripotent egg cylinder, able to generate the embryonic tissues. How pluripotency progression and morphogenesis are linked, and whether intermediate pluripotent states exist remain controversial. We identify here a rosette pluripotent state, defined by co-expression of naive factors with transcription factor OTX2. Downregulation of blastocyst WNT signals drives transition into rosette pluripotency by inducing OTX2. The rosette then activates MEK signals that induce lumenogenesis and drive progression to primed pluripotency. Consequently, combined WNT and MEK inhibition supports rosette-like stem cells (RSCs), a self-renewing naive-primed intermediate. RSCs erase constitutive heterochromatin marks and display a primed chromatin landscape, with bivalently marked primed pluripotency genes. Nonetheless, WNT induces reversion to naive pluripotency. The rosette is therefore a reversible pluripotent intermediate where control over both pluripotency progression and morphogenesis pivots from WNT to MEK signals.
Project description:Branching morphogenesis in lung development is regulate by growth factor signaling. Wnt signaling is one of the important singnaling pathway that is required for progenitor maintainance. In the presence of CHIR99021, an agonist for the beta-catenin pathway of Wnt signaling, specific group of genes are upregulated in cultured lung epithelium. RNAs were extracted from cultured epithelium and cDNAs were hybridized to Affymetrix microarrays.
Project description:Wnt signaling in early eye development, specifically the lens placode shows expression of 12 out of 19 Wnt ligands. We these Wnt activities were suppressed using conditional deletion of Wntless, dramatic phenotypic changes in morphogensis occurred. Microarray analysis of the genes that were changed in response to deletion of Wnt ligands in the developing eye region show direct or indirect responses from the surface ectoderm to the developing RPE and optic cup curvature, creating an overal shape change phenotype in the bilayerd epithelium of the optic cup. Mouse embryos at embryonic stage e10.5 were disected into pbs and eye regions were disected and removed for RNA extraction and hybridization to Affymetrix microarrays. We sought to identify the genes that were changed in response to deletion of Wls from the developing surface ectoderm of the eye region. Genes changed could be the direct or indirect result from deleltion of Wls from the surface ectoderm using the LeCre recombinase gene as a tool for analysis.
Project description:Branching morphogenesis in lung development is regulate by growth factor signaling. Wnt signaling is one of the important singnaling pathway that is required for progenitor maintainance. In the presence of CHIR99021, an agonist for the beta-catenin pathway of Wnt signaling, specific group of genes are upregulated in cultured lung epithelium.
Project description:Patterning and growth are fundamental features of embryonic development that must be tightly coordinated during morphogenesis. While metabolism is known to control cell growth, how it impacts patterning and links to morphogenesis is poorly understood. To understand how metabolism impacts early mesoderm specification during gastrulation, we used in vitro mouse embryonic stem (ES) cell-derived gastruloids, due to ease of metabolic manipulations and high-throughput nature. Gastruloids showed mosaic expression of glucose transporters co-expressing with the mesodermal marker T/Bra. To understand the significance of cellular glucose uptake in development, we used the glucose metabolism inhibitor 2-deoxy-D-glucose (2-DG). 2-DG blocked the expression of T/Bra and abolishes axial elongation in gastruloids. Surprisingly, removing glucose completely from the medium did not phenocopy 2-DG treatment despite a significant decline in glycolytic intermediates occurring under both conditions. As 2-DG can also act as a competitive inhibitor of mannose in protein glycosylation, we added mannose together with 2-DG and found that it could rescue the mesoderm specification. We corroborated these results in vivomouse embryos where supplementing mannose rescued the 2-DG mediated phenotype of mesoderm specification and proximo-distal elongation of the primitive streak. We further showed that blocking production and intracellular recycling of mannose abrogated mesoderm specification. At molecular level, proteomics analysis revealed that mannose reversed glycosylation of the Wnt pathway regulator, Secreted Frizzled Receptor, Frzb, expressed in the primitive streak of the mouse embryo. Our study showed how mannose linked metabolism to glycosylation of a developmental pathway component, crucial in patterning of mesoderm and morphogenesis of gastruloids.
Project description:In the past decade, several transcription factors critical for pancreas development have been identified. Despite this success, many of the cell surface and extracellular factors necessary for proper islet morphogenesis and function remain uncharacterized. Previous studies have shown that transgenic over-expression of the transcription factor HNF6 specifically in the pancreatic endocrine cell lineage resulted in the disruption of islet morphogenesis, including dysfunctional endocrine cell sorting, increased islet size, and failure of islets to migrate away from the ductal epithelium. We exploited the dysmorphic islets in pdx1PBHnf6 animals as a tool to identify factors important for islet morphogenesis. Genome-wide microarray analysis was used to identify differences in the gene expression profiles of late gestation and early postnatal pancreas tissue from wild type and pdx1PBHnf6 animals. We report the identification of genes with an altered expression in HNF6 Tg animals and highlight factors with potential importance in islet morphogenesis. Experiment Overall Design: Whole genome microarray analysis was used to identify differences in the gene expression profiles of late gestation and early postnatal pancreas tissue from wild type (WT) animals and HNF6 transgenic animals at a time when the events of normal islet morphogenesis are occurring (e18.5 and postnatal day 1). RNA was isolated from individual pancreata at the appropriate developmental stage. Highly pure samples were pooled according to their genotype (3-5 animals per pool) in order to obtain an adequate quantity of RNA for Affymetrix GeneChip analysis. Twelve samples were run in total, 3 replicates each of 4 groups: embryonic day 18.5, wild type mouse; embryonic day 18.5, HNF6 Transgenic mouse; post-natal day 1, wild type mouse; post-natal day 1, HNF6 Transgenic mouse.
Project description:Wnt signaling plays a major role in early neural development. An aberrant activation in Wnt/β-catenin pathway leads to defective anteroposterior patterning, resulting in neural tube closure defects (NTDs). Changes in folate metabolism may participate in early embryo fate determination. We report here that in C57BL/6C mouse embryonic stem cells (mESC), folate deficiency activates Wnt/β-catenin pathway by upregulating a chorion-specific transcription factor Gcm1. Specifically, folate deficiency promotes the formation of the Gcm1/β-catenin/T-cell factor (TCF4) complex to regulate the Wnt target gene transactivation through the Wnt-responsive elements. Moreover, the enhanced transcriptional activity of Gcm1 is found to be dependent on CREB binding protein. Lastly, in NTDs mouse models and low folate NTDs human brain samples, Gcm1 and Wnt/β-catenin target genes related to neural tube closure are specifically overexpressed. These results indicate that low folate promotes Wnt/β-catenin signaling via activating Gcm1, leading to aberrant vertebrate neural development