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:This model is an expansion of the Regan2022 - Mechanosensitive EMT model (MODEL2208050001); it includes a TGFβ signaling module and autocrine signaling in mesenchymal cells. The expanded 150-node (630 link) modular model undergoes EMT triggered by biomechanical and growth signaling crosstalk, or by TGFβ. As its predecessor, this model also reproduces the ability of the core EMT transcriptional network to maintain distinct epithelial, hybrid E/M and mesenchymal states, as well as EMT driven by mitogens such as EGF on stiff ECM. We also reproduce the observed lack of stepwise MET, in that our model's dynamics does not pass through the hybrid E/M state during MET. We show that in the absence of strong autocrine signals such as TGFβ (not included in this version), cells cannot maintain their mesenchymal state in the absence of mitogens, on softer matrices, or at high cell density. In contrast, potent autocrine signaling can stabilize the mesenchymal state in all but very dense monolayers on soft ECM. This expanded model also reproduces the inhibitory effects of TGFβ on proliferation and anoikis resistance in mesenchymal cells, as well as its ability to trigger apoptosis on soft ECM vs. EMT on stiff matrices. The model offers several experimentally testable predictions related to the effect of neighbors on partial vs. full EMT, the tug of war between mitosis and the maintenance of migratory hybrid E/M states, as well as cell cycle defects in dynamic, heterogeneous populations of epithelial, hybrid E/M and mesenchymal cells.
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:Pancreatic cancer cells exploit vesicle trafficking proteins such as myoferlin to fuel tumor aggressiveness, yet the presence and function of myoferlin-dependent vesicles in cancer-associated fibroblasts (CAFs) remain unknown. By combining PDAC whole-tumor and single-cell transcriptomic analyses with immunohistochemistry and 2D/3D in vitro models, we link stromal myoferlin to tumor aggressiveness. We identify CAF-specific functions of myoferlin, as MYOF-depleted CAFs present reduced activity and impaired extracellular matrix (ECM) production. Analysis of intracellular vesicles identifies a TGFß-receptor 1 (TGFBR1) trafficking blockade at the ER/Golgi interface upon myoferlin depletion, leading to altered TGFBR1 activation, impaired signal transduction, loss of ECM production and reduced CAF contractility. The genetic depletion of myoferlin in the murine tumor stroma and the pharmacological targeting of myoferlin alike reduced tumor desmoplasia in orthotopic KPC mice. Overall, we propose TGFBR1 trafficking as innovative target to reprogram CAFs, control desmoplasia and tackle these aggressive features in pancreatic cancer.