Project description:Identification of genes differentially expressed between epithelium and mesenchyme of embryonic lung. Embryonic lung are harvested from time pregnant mice
Project description:To identify proteins phosphorylated by Akt downstream of PI3K-mediated PDGFRalpha signaling, we immunoprecipitated Akt phosphorylation substrates from PDGF-AA-treated primary mouse embryonic palatal mesenchyme (MEPM) lysates and analyzed the peptides by nano LC-MS/MS.
Project description:During organogenesis of the intestine, reciprocal crosstalk between the endodermally-derived epithelium and the underlying mesenchyme is required for regional patterning and proper differentiation. Though both of these tissue layers participate in patterning, the mesenchyme is thought to play a prominant role in the determination of epithelial phenotype during development and in adult life. However, the molecular basis of this instructional dominance is unclear. In fact, surprisingly little is known about the cellular origins of many of the critical signaling molecules and the gene transcriptional events that they impact. Here, we profile genes that are expressed in separated mesenchymal and epithelial compartments of the perinatal mouse intestine. The data indicate that the vast majority of soluble modulators of signaling pathways such as Hedgehog, Bmp, Wnt, Fgf and Igf are expressed predominantly or exclusively by the mesenchyme, accounting for its ability to dominate instructional crosstalk. We also catalog the most highly enriched transcription factors in both compartments and find evidence for a major role for Hnf4alpha and Hnf4 gamma in the regulation of epithelial genes. Finally, we find that while epithelially enriched genes tend to be highly tissue-restricted in their expression, mesenchymally-enriched genes tend to be broadly expressed in multiple tissues. Thus, the unique tissue-specific signature that characterizes the intestinal epithelium is instructed and supported by a mesenchyme that itself expresses genes that are largely non-tissue specific. Keywords: comparative genomic hybridization: epithelium vs. mesenchyme
Project description:During organogenesis of the intestine, reciprocal crosstalk between the endodermally-derived epithelium and the underlying mesenchyme is required for regional patterning and proper differentiation. Though both of these tissue layers participate in patterning, the mesenchyme is thought to play a prominant role in the determination of epithelial phenotype during development and in adult life. However, the molecular basis of this instructional dominance is unclear. In fact, surprisingly little is known about the cellular origins of many of the critical signaling molecules and the gene transcriptional events that they impact. Here, we profile genes that are expressed in separated mesenchymal and epithelial compartments of the perinatal mouse intestine. The data indicate that the vast majority of soluble modulators of signaling pathways such as Hedgehog, Bmp, Wnt, Fgf and Igf are expressed predominantly or exclusively by the mesenchyme, accounting for its ability to dominate instructional crosstalk. We also catalog the most highly enriched transcription factors in both compartments and find evidence for a major role for Hnf4alpha and Hnf4 gamma in the regulation of epithelial genes. Finally, we find that while epithelially enriched genes tend to be highly tissue-restricted in their expression, mesenchymally-enriched genes tend to be broadly expressed in multiple tissues. Thus, the unique tissue-specific signature that characterizes the intestinal epithelium is instructed and supported by a mesenchyme that itself expresses genes that are largely non-tissue specific. Experiment Overall Design: Mouse small intestine (E18.5) is separated to epithelium and mesenchyme. Total RNA is extracted from epithelium and mesenchyme. There are 6 samples in this microarray experiment: 3 for epithelium and 3 for mesenchyme. Samples are hybridized the affymetrix Mouse Genome 430 2.0 Array. We compare the gene expression between epithelium and mesenchyme to study the gene expression profiles in these two compartments.
Project description:Purpose: The aim of this study is to study the expression and function of axon guidance genes in the developing portal tract. Here, the RNA-Sequencing data were collected from purified embryonic mesenchyme at two developmental stages (E16 and E18).
Project description:The effects of Wnt7b on lung development were examined using a conditional Wnt7b-null mouse. Wnt7b-null lungs are markedly hypoplastic, yet display largely normal patterning and cell differentiation. In contrast to findings in prior hypomorphic Wnt7b models, we find decreased replication of both developing epithelium and mesenchyme, without abnormalities of vascular smooth muscle development. We further demonstrate that Wnt7b signals to neighboring cells to activate both autocrine and paracrine canonical Wnt signaling cascades. In contrast to results from hypomorphic models, we show that Wnt7b modulates several important signaling pathways in the lung. Together, these cascades result in the coordinated proliferation of adjacent epithelial and mesenchymal cells to stimulate organ growth with few alterations in differentiation and patterning.
Project description:Smooth muscle guides morphogenesis of epithelia during development of several organs, including the mammalian lung. However, it remains unclear how airway smooth-muscle differentiation is spatiotemporally patterned and whether it originates from distinct mesenchymal progenitors. Using single-cell RNA-sequencing of embryonic mouse lungs, we show that the pulmonary mesenchyme contains a continuum of cell identities, but no distinct progenitors. Transcriptional variability correlates with sub-epithelial and sub-mesothelial mesenchymal compartments that are regulated by Wnt signaling. Live-imaging and tension sensors reveal patterned migratory behaviors and cortical forces in each compartment, and show that sub-epithelial mesenchyme gives rise to airway smooth muscle. Differentiation trajectory reconstruction reveals that cytoskeleton, adhesion, and Wnt signaling pathways are activated early in differentiation. Finally, we show that Wnt activation stimulates the earliest stages of differentiation and induces local accumulation of mesenchymal F-actin, which influences epithelial morphology. Our work provides the first single-cell view of pulmonary mesenchymal patterning during branching morphogenesis.
Project description:Reciprocal signaling between an epithelium and its surrounding mesenchyme is common during morphogenesis. These epithelial-mesenchymal interactions are particularly evident in tissues that undergo branching morphogenesis, such as the airway epithelium of the lung. Here, we found that reciprocal interactions between the epithelium and mesenchyme drive remodeling of the extracellular matrix (ECM) during morphogenesis of the embryonic chicken lung. RNA-Seq analysis revealed changes in the expression of genes associated with integrin signaling and ECM remodeling. Consistently, we found that prior to branching, the basement membrane is a spatially uniform sheath that wraps the airway epithelium. After branch initiation, however, the basement membrane is significantly depleted from the tip of extending branches. Culturing embryonic lung explants revealed that this basement membrane thinning is mediated by matrix metalloproteinase-2 (MMP2), which is expressed in the mesenchyme. Inhibiting MMP activity suppresses branch extension but has no effect on branch initiation. As branches extend, we found that tenascin-C (TNC) accumulates in the mesenchyme several cell diameters away from the branch tip. Despite its pattern of accumulation, this mesenchymal ECM protein is expressed exclusively by airway epithelial cells, which activate focal adhesion kinase (FAK) to induce TNC expression. We found that branch extension coincides with the deformation of adjacent mesenchymal cells into elongated geometries, which correlates with an increase in the fluidity of the mesenchyme at branch tips. This local increase in mesenchymal movement transports TNC from the epithelial surface into the mesenchyme. These data reveal novel epithelial-mesenchymal interactions that direct ECM remodeling during airway branching morphogenesis.