Project description:Axin2-expressing calvarial suture stem cells can contribute to calvarial development, homeostatic maintenance, repair, and regeneration. We used microarray to examine the gene expression profiles of Axin2-expressing suture stem cells and Axin2-negative cells in suture mesenchyme.
Project description:The regeneration of craniofacial bones of the mammalian skeleton necessitates the action of both intrinsic and extrinsic inductive factors from multiple cell types, which function in a hierarchical and temporal fashion to control the differentiation of osteogenic progenitors. Single-cell transcriptomics of developing mouse cranial suture recently identified a suture mesenchymal progenitor population with tendon- or ligament-associated gene expression profile previously uncharacterized. Here, we developed a Mohawk homeobox (MkxCG;R26RtdT) reporter mouse, finding that this teno-ligamentous gene identifies a cranial suture resident cell population within the adult mouse that gives rise to calvarial osteoblasts and osteocytes overtime during homeostatic conditions. Single cell RNA-Sequencing (scRNA-Seq) demonstrated that Mkx+ suture cells demonstrate a stem-like phenotype with expression of teno-ligamentous genes. Bone injury with Mkx+ cell ablation showed delayed bone healing. Remarkably, Mkx gene played a critical role as an osteo-inhibitory factor in cranial suture cells, as knockdown or knockout resulted in increased osteogenic differentiation. Furthermore, in vivo local deletion of Mkx in Mkx floxed mice resulted in robustly increased calvarial defect repair. Finally, we observed that mechanical stretch dynamically regulates Mkx expression in turn regulating calvarial cell osteogenesis. Overall, we identify Mkx+ cells within the suture mesenchyme as a progenitor cell population for adult craniofacial bones required for bone repair and Mkx itself as mechanical stretch responsive gene which functions to prevent osteogenic differentiation within the stem cell niche.
Project description:The regeneration of craniofacial bones of the mammalian skeleton necessitates the action of both intrinsic and extrinsic inductive factors from multiple cell types, which function in a hierarchical and temporal fashion to control the differentiation of osteogenic progenitors. Single-cell transcriptomics of developing mouse cranial suture recently identified a suture mesenchymal progenitor population with tendon- or ligament-associated gene expression profile previously uncharacterized. Here, we developed a Mohawk homeobox (MkxCG;R26RtdT) reporter mouse, finding that this teno-ligamentous gene identifies a cranial suture resident cell population within the adult mouse that gives rise to calvarial osteoblasts and osteocytes overtime during homeostatic conditions. Single cell RNA-Sequencing (scRNA-Seq) demonstrated that Mkx+ suture cells demonstrate a stem-like phenotype with expression of teno-ligamentous genes. Bone injury with Mkx+ cell ablation showed delayed bone healing. Remarkably, Mkx gene played a critical role as an osteo-inhibitory factor in cranial suture cells, as knockdown or knockout resulted in increased osteogenic differentiation. Furthermore, in vivo local deletion of Mkx in Mkx floxed mice resulted in robustly increased calvarial defect repair. Finally, we observed that mechanical stretch dynamically regulates Mkx expression in turn regulating calvarial cell osteogenesis. Overall, we identify Mkx+ cells within the suture mesenchyme as a progenitor cell population for adult craniofacial bones required for bone repair and Mkx itself as mechanical stretch responsive gene which functions to prevent osteogenic differentiation within the stem cell niche.
Project description:Axin2-expressing calvarial suture stem cells can contribute to calvarial development, homeostatic maintenance, repair, and regeneration. We used microarray to examine the gene expression profiles of Axin2-expressing suture stem cells and Axin2-negative cells in suture mesenchyme. Three of Axin2+/GFP+ and three of Axin2-/GFP- cell samples were collected from mice carrying Axin2rtTA and TREH2BGFP transgenes. Each samples were isolated from 6-8 Axin2rtTA; TRE-H2BGFP mice and sorted by the GFP intensity.
Project description:Craniofacial development depends on formation and maintenance of sutures between bones of the skull. In sutures, growth occurs at osteogenic fronts along the edge of each bone and suture mesenchyme separates adjacent bones. We performed single-cell RNA-seq analysis of the embryonic, murine coronal suture. Seven populations at E16.5 and nine at E18.5 comprised the suture mesenchyme, osteogenic cells, and associated populations. Expression of Hhip, an inhibitor of hedgehog (HH) signaling, marked a mesenchymal population distinct from other neurocranial sutures. At E18.5, Hhip-/- coronal osteogenic fronts were closely apposed and HH signaling was increased throughout the depleted suture mesenchyme compared to WT, demonstrating that Hhip is required for normal coronal suture development. Tracing of the neonatal Hhip-expressing population showed that descendant cells persisted in the coronal suture and contributed to calvarial bone growth. Our transcriptomic approach provides a rich resource for insight into normal and abnormal development.
Project description:PURPOSE: To provide a detailed gene expression profile of the normal postnatal mouse cornea. METHODS: Serial analysis of gene expression (SAGE) was performed on postnatal day (PN)9 and adult mouse (6 week) total corneas. The expression of selected genes was analyzed by in situ hybridization. RESULTS: A total of 64,272 PN9 and 62,206 adult tags were sequenced. Mouse corneal transcriptomes are composed of at least 19,544 and 18,509 unique mRNAs, respectively. One third of the unique tags were expressed at both stages, whereas a third was identified exclusively in PN9 or adult corneas. Three hundred thirty-four PN9 and 339 adult tags were enriched more than fivefold over other published nonocular libraries. Abundant transcripts were associated with metabolic functions, redox activities, and barrier integrity. Three members of the Ly-6/uPAR family whose functions are unknown in the cornea constitute more than 1% of the total mRNA. Aquaporin 5, epithelial membrane protein and glutathione-S-transferase (GST) omega-1, and GST alpha-4 mRNAs were preferentially expressed in distinct corneal epithelial layers, providing new markers for stratification. More than 200 tags were differentially expressed, of which 25 mediate transcription. CONCLUSIONS: In addition to providing a detailed profile of expressed genes in the PN9 and mature mouse cornea, the present SAGE data demonstrate dynamic changes in gene expression after eye opening and provide new probes for exploring corneal epithelial cell stratification, development, and function and for exploring the intricate relationship between programmed and environmentally induced gene expression in the cornea. Keywords: other
Project description:In this study, RNA sequencing was employed to investigate the differences in gene expression levels and patterns of cells recruited into suture-bony combined calvarial injury following the implatation of distinct types of commonly used calvarial scaffolds including gelatin methacryloyl hydrogel (GelMA), porous chitosan scaffold (CTS), and polylactic acid eletrospinning membrane (PLA).
Project description:Suture mesenchymal stem cell (MSC) drives calvarial suture development, homeostasis, and regeneration. Its loss leads to craniosynostosis, a prevailing craniofacial disorder characterized by premature suture closure. Ribosome biogenesis, historically thought to be a static house-keeping process, is now known to have tissue-specific roles. However, the functional specificity of ribosome biogenesis in suture MSCs remains largely unexplored, hampering development of therapeutic strategies for craniofacial tissue regeneration. We genetically perturb ribosome biogenesis using Snord118, a small nucleolar RNA (snoRNA) required for ribosomal RNA (rRNA) maturation. MSC specific conditional knockout (cKO) of Snord118 in mice leads to p53 activation, cell death, mesenchymal and MSC loss, impaired osteogenic and osteoclastic activity, resulting in suture growth and craniosynostosis defects. Using our newly established human induced pluripotent stem cell (iPSC)-derived MSCs combined with ribosome profiling, we found that SNORD118deficiency in MSCs causes global translation dysregulations and downregulation of complement pathway, a part of innate immune system with selective but poorly characterized physiological functions in craniofacial tissue homeostasis. Overall, ribosome biogenesis controls suture MSC fate via selective regulation of complement pathway.
Project description:Suture mesenchymal stem cell (MSC) drives calvarial suture development, homeostasis, and regeneration. Its loss leads to craniosynostosis, a prevailing craniofacial disorder characterized by premature suture closure. Ribosome biogenesis, historically thought to be a static house-keeping process, is now known to have tissue-specific roles. However, the functional specificity of ribosome biogenesis in suture MSCs remains largely unexplored, hampering development of therapeutic strategies for craniofacial tissue regeneration. We genetically perturb ribosome biogenesis using Snord118, a small nucleolar RNA (snoRNA) required for ribosomal RNA (rRNA) maturation. MSC specific conditional knockout (cKO) of Snord118 in mice leads to p53 activation, cell death, mesenchymal and MSC loss, impaired osteogenic and osteoclastic activity, resulting in suture growth and craniosynostosis defects. Using our newly established human induced pluripotent stem cell (iPSC)-derived MSCs combined with ribosome profiling, we found that SNORD118deficiency in MSCs causes global translation dysregulations and downregulation of complement pathway, a part of innate immune system with selective but poorly characterized physiological functions in craniofacial tissue homeostasis. Overall, ribosome biogenesis controls suture MSC fate via selective regulation of complement pathway.