Project description:To identify genes heretofore undiscovered as critical players in the biogenesis of teeth, we have used microarray gene expression analysis of the developing mouse molar tooth (DMT) between 1 and 10 days postnatal to identify genes differentially expressed when compared to 16 control tissues (GEO accession # GSE1986). Of the top 100 genes exhibiting increased expression in the DMT, 29 were found to have been previously associated with tooth development. Differential expression of the remaining 71 genes not previously associated with tooth development was confirmed by qRT-PCR analysis. Further analysis of seven of the latter genes by mRNA in situ hybridization found that five were specific to the developing tooth in the craniofacial region (Rspo4, Papln, Amtn, Gja1, Maf). Of the remaining two, one was found to be more widely expressed (Sp7) and the other was found to be specific to the nasal serous gland, which is close to, but distinct from, the developing tooth (Vrm). Experiment Overall Design: mRNA from molar teeth extracted from Swiss Webster mouse pups between 1 and 10 days post-natal was pooled, labeled, and hybridized in quadruplicate to Affymetrix Mouse Genome Expression 430 2.0 microarrays. This data was compared to that of 16 control tissues (GEO accession # GSE1986) to identify genes differentially expressed in the DMT mRNA.
Project description:Organoid models provide powerful tools to study tissue biology and development in a dish. Here, we established first-time organoid models from early-postnatal (postnatal day 7) mouse molar and incisor, capable of differentiation toward ameloblast-like cells in vitro. To more in detail characterise organoids from mouse molar and incisor, bulk RNA-sequencing was performed on the following (1) early passage (passage 0) organoids from both tooth types grown in basal tooth organoid medium (TOM) with or without addition of exogenous epidermal growth factor (EGF); and (2) late passage (passage 5) organoids grown in TOM+EGF or differentiation medium (DM).
Project description:Embryologically the tooth is derived from both the ectoderm and neural crest (ectomesenchyme). It is often used as a model to study how epithelialmesenchymal interactions can control differentiation and morphogenesis. During early development organs of ectodermal origin share both a set of signalling molecules and exhibit common morphological features, subsequently proceeding along separate developmental programs.<br><br>Tooth development is a continuous process that can be divided into the initiation -, bud -, cap -, and bell-stages. In mice, tooth development begins at embryonic day 11.5 (E11.5), by thickening of the dental epithelium, while mineralization of enamel and dentin in first molar starts at postnatal day 0 (P0) (5). A multistep and complex process of the gene expression are involved in the early stage of tooth development. So far expression of more than 1300 genes and/or proteins have been detected during tooth germ development by microarrays/immunocytochemistry/in situ hybridization. Studies with mutant mice have identified a number of genes that regulate tooth development and morphology. For example, deficiency of Lef-1 or P63 arrests tooth development at early stages. Deficiency of Msx1 or Pax9 results in arrest of tooth development at the bud stage , while deficiency of Runx2/Cbfa1 or Sp3 inhibits cyto-differentiation of ameloblasts and/or odontoblasts. Shh is required for normal growth and morphogenesis, but is not essential for cyto-differentiation of the ameloblast and odontoblast populations. Ameloblastin and amelogenin knock-out mice develop severe enamel hypoplasia with abnormal ameloblast differentiation. <br><br>Recently, new connections between retinoid metabolism and PPAR responses have been identified. It has also been shown that endogenous retinoic acid is necessary for the initiation of odontogenesis , and that some of the genes that catalyze the oxidation of retinaldehyde into retinoic acid, exhibit distinct patterns of expression in developing murine teeth. Little is known about functions of PPAR-a as regards tooth germs or mature teeth. It is, however, likely that mitochondrial oxidative metabolism well as fatty acid metabolism is enhanced in late odontogenesis. These are metabolic activities which in other tissues are stimulated by PPAR-a agonists.<br><br>For this reason it was of interest to carry out comparative gene expression profiling of the first molar tooth germs of PPAR-a knock-out mouse and of the corresponding wild-type mice. The results suggest marked differences in gene expression, parts of which may be associated with an observed hypomineralization of enamel in the mature PPAR-a knock-out murine tooth.
Project description:Throughout the various stages of tooth development, reciprocal epithelial-mesenchymal interactions are the driving force, for instance crucially involved in the differentiation of mature enamel-forming ameloblasts and dentin-producing odontoblasts. Here we established mouse tooth ‘assembloids’, comprised of tooth organoid-derived dental epithelial cells (from mouse molars and incisors) cultured together with molar dental pulp stem cells (DPSCs), to mimic these developmental interactions. Assembloids from both tooth types were grown both in basal- and differentiation-inducing conditions. Single cell transcriptomics analysis was applied to in detail characterize and validate the newly developed mouse tooth assembloid model and evaluate the induced differentiation processes.
Project description:The tooth is derived from both the ectoderm and the neural crest (ectomesenchyme). It is often used as a model for studies of the basic mechanisms of organ development, including differentiation, cellular interaction, morphogenesis, and mineralization of extracellular matrices. In mouse, tooth development begins at embryonic day 11.5 (E11.5) by thickening of the dental epithelium, whereas mineralization of enamel and dentin in first molars starts at postnatal day 0 (P0). Tooth development entails a multistep and complex process of gene expression. Studies with genetically modified mice have contributed substantially to our understanding of genes that regulate tooth development and morphology. MicroRNAs (miRNA) are a class of non-coding RNAs that regulate gene expression at a post-transcriptional level, and are considered as important regulatory molecules during foetal development. By binding to target mRNAs, miRNA induce mRNA decay or translation repression. Recent bioinformatic predictions of miRNA targets in vertebrates indicate that hundreds of miRNAs are responsible for regulation of expression of up to 30% of the human protein-coding genes. Recent experiments has verified that miRNAs can regulate expression of hundreds of mRNAs in cultured cells. Previous study has also shown that microarrays can be used to detect physiologically relevant effects of miRNAs on expression of mRNAs in vertebrates; miRNAs have been shown to alter expression of a greater number of transcripts than previously appreciated, primarily through interaction with 3M-4UTRs. Understanding the biological function of miRNAs require knowledge of their mRNA targets. Bioinformatic approaches have been used to predict mRNA targets, among which both transcription factors and pro-apoptopic genes were prominent candidates. The precise molecular function of miRNAs remains largely unknown and a better understanding may require loss-of-function studies in vivo. It has been shown that intravenous administration of a novel class of chemically engineered oligonucleotides termed M-^SantagomirsM-^T resulted in a marked reduction of corresponding miRNA levels in most tissues. This resulted in upregulated expression of hundreds of genes predicted to be repressed by miR-122 because these genes had a miR-122 recognition motif in their 3M-4UTR region. Paradoxically, antagomir treatment also revealed a significant number of downregulated genes that may be activated by miR-122. The mechanism by which miRNAs may activate gene expression in vivo is unknown. However, it may involve an indirect effect (the suppression of a transcriptional repressor), or alternatively, miRNA may have a direct effect on gene activation (e.g. chromatin remodeling). Studies of microRNA expression profiles of the developing murine molar tooth germ have shown these to be highly dynamic, some miRNAs being abundantly expressed during the early development of the molar tooth germ, while others are highly expressed only at later developmental stages. A recent study also suggested that miRNAs modulate tooth morphogenesis and ameloblast differentiation, perhaps largely by fine tuning conserved signaling networks. The function of microRNA-214 (miR-214) is unknown, however, it has been related to normal growth and skeletal development in mice. In tooth germs miR-214 is more highly expressed during later developmental stages. It was selected as a target for silencing using anti-miR-214. Here we report effects from injections of 1-100 pmol of anti-miR-214 close to developing first mandibular molar in newborn mice. At 24 hrs, or more, after injection significant changes in gene expression, and in levels of several correspondingly encoded proteins, were found in the tooth germ.
Project description:Foxi3 is a transcription factor expressed in the epithelium during tooth development. In this study we used a microarray analysis to indentify differentially expressed genes in bud stage (E13.5 ) mandibular molar epithelium of conditional Foxi3 knock-out embryos compared to control littermates.
Project description:miRNAs are not well known their expression and function in tooth development. To identify the miRNAs expression during tooth development, tooth germs were dissected from the initiation bud, cap and bell stages. miRNA-chip expression analysis was performed with RNAs of the molar tooth germs from embryos of pregnant mice at emrbryonic day 11, 12, 14, and 16, using Agilent's miRNA microarray.
Project description:A single cell transcriptional profile of both epithelial and mesenchymal cells in the tooth bud of the murine molar marked by Gli1-GFP+ tooth root progenitor cells or PTHrP+ dental follicle cells at postnatal day 6 (P6)
Project description:Numerous genes that play important regulative roles during tooth development in mice have been identified. However, very little is known about gene expression and function in human odontogenesis. We used microarrays to detail the global programme of gene expression underlying tooth development and identified distinct classes of up-regulated genes during in the tooth germs. Tooth germs of molar, incisor, and canine at the cap stage were dissected, respectively, from 12-week-old human embryonic oral cavity for RNA extraction and hybridization on Affymetrix microarrays. We sought to screen for the genes that are strongly expressed in the dental tissues and analysis if these genes related to mammalian tooth development and tooth abnormalities.