Project description:We used single-cell sequencing to understand the development of incisor tissues from mice. We utilized the single-cell sequencing platform from SeekGene Biotechnology to study the heterogeneity of mesenchyme in incisors at both embryonic and adult stages of mice, and discovered that Smoc2 is a marker gene for mesenchymal stem cells in mouse incisors. We employed the 10X platform to sequence the incisor tissues of smoc1/2 knockout (ko) and control mice during the embryonic stage to investigate the molecular mechanisms underlying the developmental abnormalities in smoc1/2 ko mice.Our study provides a molecular mechanism explaining how stem cells form during development.
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:The overall goal of this project is to investigate the contribution of the inferior alveolar nerve (IAN) towards cellular mechanisms required for regeneration of the murine incisor. Here, we conducted gene expression profiling of adult murine incisor dental mesenchyme tissue following two weeks after unilateral resection of the IAN from both the denerved and contralateral incisor of five wild-type mice.
Project description:Molar incisor hypomineralization (MIH) is an endemic pediatric disease with an unclear pathogenesis. Considering that saliva control remineralization of enamel and that MIH is associated with higher saliva flow rate it is reasonable to suggest that also the composition of saliva is affected by the disease.
Project description:One of the key questions in developmental biology is how from universally shared molecular mechanisms and pathways, is it possible to generate organs displaying similar or complementary functions, with a wide range of different shapes or tissue organization? The dentition represents a valuable system to address the issues of differential molecular signatures generating specific tooth types. We performed a comparative transcriptomic analysis of developing murine lower incisors, mandibular molars and maxillary molars at the developmental cap stage (E14.5) prior to recognizable tooth shape and cusp pattern. We compared gene expression profiles in developing murine lower incisor and molars, as well as between the lower and upper (mandibular and maxillary) first molars
Project description:miRNA expression was compared in 3 distinct regions of the adult mouse incisor: the labial cervical loop, which houses ameloblast stem cells; the lingulal cervical loop, which houses stem cells but not ameloblast stem cells; and ameloblasts. Differentially expressed miRNAs from these regions are likely involved in the renewal and differentiation of stem cells. miRNA expression in the labial and lingual cervical loops, and ameloblasts were compared from 5 specimens.
Project description:The precise timing of stem cell specification and niche formation during murine incisor development is poorly understood, and it is unclear whether these processes occur simultaneously or in a sequential manner. Functional dental epithelial stem cells are marked by the expression of Sox2, a transcription factor that is broadly expressed in the dental epithelium at the dentition onset and restricted to stem cells in fully developed incisor. Using genetic lineage tracing in Sox2CreERT2/+; R26RmT/mGand Sox2CreERT2/+; R26RtdT/+embryos along with a single-cell RNA sequencing at different stages of incisor development, we investigated the timing of the stem cell specification and its temporal relationship with niche formation. Our results reveal the presence of a Sox2-expressing stem cell-like population prior to formation of the functional niche. These cells localize to the leading edge of the advancing incisor epithelium where they are maintained in an undifferentiated state. Our data demonstrate presence of actomyosin network and a generation of a contractile tension which helps confine Sox2+ stem cells to the leading edge. This mechanical confinement likely plays an important role in maintaining their stemness until the niche is functionally and structurally established. Partial or complete disruption of the actomyosin network disables the clustering of Sox2-expressing cells, potentially triggering their premature differentiation, and ultimately leads to impaired formation of the functional stem cell niche and abnormal growth of the incisor.
Project description:miRNA expression was compared in 3 distinct regions of the adult mouse incisor: the labial cervical loop, which houses ameloblast stem cells; the lingulal cervical loop, which houses stem cells but not ameloblast stem cells; and ameloblasts. Differentially expressed miRNAs from these regions are likely involved in the renewal and differentiation of stem cells.
Project description:Lipid droplets (LDs) are dynamic organelles that regulate cellular metabolism, yet their role in tumor immune evasion remains unclear. Here, we demonstrate that LDs impair anti-tumor immunity by disrupting the membrane localization of interferon-gamma receptor 1 (IFNGR1). Tumor cells with reduced LD content exhibit heightened susceptibility to immune-mediated cytotoxicity in vitro, in murine immunotherapy models, and in patients undergoing immune checkpoint blockade. Mechanistically, IFNGR1 trafficking to the plasma membrane is dependent on diacylglycerol (DAG) in the trans-Golgi network (TGN). However, LDs sequester DAG, impeding IFNGR1 trafficking and attenuating JAK2-STAT1 signaling. Notably, genetic or pharmacological depletion of LDs enhances tumor sensitivity to anti-PD-1 therapy. These findings establish LDs as immunosuppressive organelles that compromise interferon signaling, highlighting their potential as therapeutic targets to improve cancer immunotherapy outcomes.
Project description:The tooth is a convenient experimental model for the study of the basic mechanisms of organ development, including differentiation, cellular interaction, morphogenesis, and production and mineralization of extracellular matrices. The rodent incisor teeth grow continuously and exhibit all stages of tooth development at any time. This characteristic makes them convenient models for the study of enamel formation, which occurs in several distinct stages along the tooth axis. The distribution and structure of mouse incisor enamel resemble that of the rat. The enamel covers only the labial aspect of the tooth, and can be divided into four layers: a thin inner prism-free layer, inner enamel with prism decussation, i.e. transverse rows of prisms with prisms inclined medially and laterally in alternate rows, outer enamel with parallel prisms inclined incisally and a thin superficial prism-free layer. Recently, we have described how this elaborate organization of the enamel is established in the initial enamel formed on the unerupted and unworn incisal tip of the incisors. The very first enamel formed, i.e. the most incisally situated enamel, is always prism-free, corresponding to the superficial layer in fully established enamel, although thicker. Going in apical direction, i.e. in the direction of initiation of new enamel formation, isolated prisms appear among the crystals continuous with the prism-free zone crystals. These initial prisms are in general inclined incisally, corresponding to the prisms in the outer enamel layer in the fully established enamel. Inner enamel with the characteristic decussation pattern is added somewhat further apically and increases in thickness with increasing enamel thickness. Based on the structure of the enamel that they produce, the ameloblasts producing the initial, thin, prism-free enamel at the incisal tip of the unworn mouse incisor are probably differently configured (e.g. lacking Tomes' processes), probably differently organized (e.g. not organized in transverse rows moving sideways in opposite directions), and probably have a shorter life-span than the more apically situated ameloblasts which produce thicker enamel with the full four-layered configuration of mouse incisor enamel. For this reason it would be of interest to compare the gene expression profile of the incisal tip segment where prism-free enamel is being formed with the profile of the immediately adjacent segment where enamel with all four layers is being formed. As long as the incisor is unworn enamel formation and gene expression in these segments will likely reflect mechanistic differences between these segments as regards enamel biosynthesis. 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 mRNA, miRNA induce mRNA decay or translation repression. Recent bioinformatic predictions of miRNA targets in vertebrates indicate that hundreds of miRNAs are responsible for regulating the expression of up to 30% of the human protein-coding genes, and miRNAs have recently also been shown to regulate expression of hundreds of mRNAs in cultured cells. Recently, miRNA expression profiles of the developing murine molar tooth germ and submandibular salivary gland have been established. We here report expression profiling of miRNAs present in the two adjacent segments of the incisor tooth germ on which we also have carried out mRNA expression profiling. The results suggest that also miRNAs are abundantly, and differentially, expressed during development of the incisor tooth germ in mouse. By analogy with the mRNA data also miRNA expression is dynamic, with respect to both the two incisor segments investigated and to the developmental stage of the incisor.