Project description:The aim of this study was to evaluate and compare the gene expression profiles of dental follicle and periodontal ligament in humans, which can possibly explain their functions of dental follicle and PDL such as eruption coordination and stress resorption. That may apply this information to clinical problem like eruption disturbance and to periodontal tissue engineering. PDL samples were obtained from permanent premolars (n=11) and dental follicle samples were obtained during extraction of supernumerary teeth (n=4). Comparative cDNA microarray analysis revealed several differences in gene expression between permanent PDL and dental follicles.
Project description:The dentition of elasmobranchs (sharks, skates and rays) is uniquely productive, capable of both rapid and continuous, lifelong regeneration. Elasmobranchs represent an important group of vertebrates with a deep evolutionary history, possessing several ancient and basal characters, i.e., the continuously regenerative dentition from a specialized dental lamina. The dental lamina is an expanded component of the oral epithelia that is responsible for initiating and producing new teeth among all toothed-vertebrates. In sharks, this dynamic epithelial unit is permanent and continuous – meaning it extends to cover the entirety of each jaw (jaw-wide) and develops early during embryogenesis and retained to produce teeth for the life of the shark. It is rare for a truly embryonic vertebrate tissue to be retained for its original function for the life of the organism. The dental lamina in sharks is unique and houses teeth in a developmental series from the deepest part, where teeth are initiated, through stages of tooth development in the form of a related, family of teeth to eruption and functionality of the advanced teeth at the jaw margin. How teeth are made and regenerated is an important question in vertebrate biology; here we investigated this question in the small spotted catshark (Scyliorhinus canicula), a new model in the field of developmental biology. Specifically, we divided the shark dental lamina into stage-compartments as follows: (i) the initiation site – the successional lamina (SL); (ii) the early developing teeth (ET); (iii) the late stage developing teeth (LT); (iv) the tooth-taste junction between the superficial oral and dental epithelium at the jaw margin that separates the taste territory and the dental lamina proper (TTJ); and basi-hyal oral epithelium that is strictly non-dental and only contains taste buds (BHTB). These 5 compartments each house both a shared and unique signature of gene transcripts. This study aims to understand the transcriptomic basis of continuous tooth regeneration in the shark. In this study we combine X-ray computed tomography, classic histology, insitu hybridization, immunohistochemistry, and functional assays of novel markers, and de novo and genome guided transcriptome assemblies for each of these 5 dental lamina compartments of the hatchling (stage 34) catshark (S. canicula).
Project description:The discovery of activity-dependent neuroprotective protein (ADNP) regulated tooth eruption in mice and man, provides, for the first time, an early detection of tooth eruption, with full or almost full mouth of teeth at one year of age, as a potential biomarker for an intellectual disability (ID)/autism spectrum disorder (ASD) syndrome, toward improved translational medicine.
Project description:Tooth eruption is a continuous biological proces with dynamic changes at cellular and tissue levels particularly within the periodontal ligament (PDL). Occlusion completion is a significant physiological landmark of dentintion establishment. However the implication and molecular networks engaging in of this event on the the final PDL maturation are still largely unknown. In this study, using rat and mouse molar teeth and transgenic approaches, as well as a human PDL cell line by combining RNAseq and proteomic analysis systematically, we screened the key molecular links in regulating PDL maturation before and after occlusion establishiment. We discovered Notch, a key molecular pathway in regulating stem cell fate and differentiation, is a major player in the event. Intercepting Notch pathway by deleting its key canonical transtripitonal factor: RBP-Jkappa using conditional knocking out strategy in the mice delayed PDL maturation. We also identified that Lamin A, a cell nuclear lamina member, is one unique marker of PDL maturation and its expression is under the control of Notch signalling. Our study therefore provides a deep insight of how PDL maturation is regulated molecularly and we expect the outcomes to be applied to better understand the molecular regulation networks and physiological conditions such as tooth eruption and movement, and also for periodontal diseases.
Project description:Here we use single nuclei RNA sequencing (snRNA-seq) of replacement teeth and adjacent oral lamina in Lake Malawi cichlids, species with lifelong whole-tooth replacement, to make two main discoveries. First, despite hundreds of millions of years of evolution, we demonstrate conservation of cell type gene expression across vertebrate teeth (fish, mouse, human). Second, we used an approach that combines marker gene expression and developmental potential of dental cells to uncover the transcriptional signature of stem-like cells in regenerating teeth. Our work underscores the importance of a comparative framework in the study of vertebrate oral and regenerative biology.
Project description:Here we use single nuclei RNA sequencing (snRNA-seq) of replacement teeth and adjacent oral lamina in Lake Malawi cichlids, species with lifelong whole-tooth replacement, to make two main discoveries. First, despite hundreds of millions of years of evolution, we demonstrate conservation of cell type gene expression across vertebrate teeth (fish, mouse, human). Second, we used an approach that combines marker gene expression and developmental potential of dental cells to uncover the transcriptional signature of stem-like cells in regenerating teeth. Our work underscores the importance of a comparative framework in the study of vertebrate oral and regenerative biology.
Project description:Opioid analgesics are frequently prescribed in the United States and worldwide. However, serious side effects such as addiction, immunosuppression and gastrointestinal symptoms limit long term use. In the current study using a chronic morphine-murine model a longitudinal approach was undertaken to investigate the role of morphine modulation of gut microbiome as a mechanism contributing to the negative consequences associated with opioids use. The results revealed a significant shift in the gut microbiome and metabolome within 24 hours following morphine treatment when compared to placebo. Morphine induced gut microbial dysbiosis exhibited distinct characteristic signatures profiles including significant increase in communities associated with pathogenic function, decrease in communities associated with stress tolerance. Collectively, these results reveal opioids-induced distinct alteration of gut microbiome, may contribute to opioids-induced pathogenesis. Therapeutics directed at these targets may prolong the efficacy long term opioid use with fewer side effects.
Project description:The pre-occlusal eruption brings the rat molars into functional occlusion, which implicates tensional strains during mastication. We hypothesized that upon establishment of occlusion, the periodontal ligament undergoes cell and extracellular matrix maturation to adopt to this mechanical function. We thus aimed to characterize the protein content and changes in expression levels of tensionally relevant extracellular matrix components in the periodontal ligament between the eruption and newly established occlusion in rat molars. Twelve Wistar male rats were divided into 3 groups based on eruption and occlusal stages: covering the pre-occlusal stages at time of eruption, the first day of occlusion and 1 week after occlusion. We employed laser capture microdissection to obtain samples of the periodontal ligament at three regions, cervical, apical and subapical. The proteome was screened with Tandem Mass Tag 10-plexTM mass spectrometry and the expression of key proteins were confirmed by immunofluorescence. Differential expression of matrisome proteins was seen in the cervical and the apical region. Downregulation of pro-metabolic proteins, such as apolipoproteins implicated in lipid transport was observed. Alpha-fetoprotein, a stem cell marker, was also downregulated indicating cell differentiation and PDL maturation. Upregulated proteins were components of the extracellular matrix, involving several proteoglycans and glycoproteins and the matrisome was thus further analyzed. Periostin appeared around collagen α-1 (III) fibers and its expression was particularly strong on Sharpey’s fibers. This co-localization coincided with organization of collagen fibers in direction of the occlusal forces. Establishment of occlusion coincides with cellular differentiation and the maturation of the extracellular matrix of the periodontal ligament, as seen by downregulation of the stem cell marker Alpha-fetoprotein and apolipoproteins, and the progressive accumulation of collagen type III fibers, proteoglycans, glycoproteins. The increase in collagen fiber associates periostin may reflect a physiological response to enforce cell-ECM contacts during PDL maturation.