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Journal of Biological Engineering Dec 2023Three-dimensional (3D) cell cultures are to date the gold standard in biomedical research fields due to their enhanced biological functions compared to conventional...
Three-dimensional (3D) cell cultures are to date the gold standard in biomedical research fields due to their enhanced biological functions compared to conventional two-dimensional (2D) cultures. 3D cell spheroids, as well as organoids, are better suited to replicate tissue functions, which enables their use both as in vitro models for basic research and toxicology, as well as building blocks used in tissue/organ biofabrication approaches. Culturing 3D spheroids from bone-derived cells is an emerging technology for both disease modelling and drug screening applications. Bone tissue models are mainly limited by the implementation of sophisticated devices and procedures that can foster a tissue-specific 3D cell microenvironment along with a dynamic cultivation regime. In this study, we consequently developed, optimized and characterized an advanced perfused microfluidic platform to improve the reliability of 3D bone cell cultivation and to enhance aspects of bone tissue maturation in vitro. Moreover, biomechanical stimulation generated by fluid flow inside the arrayed chamber, was used to mimic a more dynamic cell environment emulating a highly vascularized bone we expected to improve the osteogenic 3D microenvironment in the developed multifunctional spheroid-array platform. The optimized 3D cell culture protocols in our murine bone-on-a-chip spheroid model exhibited increased mineralization and viability compared to static conditions. As a proof-of-concept, we successfully confirmed on the beneficial effects of a dynamic culture environment on osteogenesis and used our platform for analysis of bone-derived spheroids produced from primary human pre-osteoblasts. To conclude, the newly developed system represents a powerful tool for studying human bone patho/physiology in vitro under more relevant and dynamic culture conditions converging the advantages of microfluidic platforms with multi-spheroid array technologies.
PubMed: 38098075
DOI: 10.1186/s13036-023-00395-z -
Proceedings. Biological Sciences Dec 2023Pronounced over-eruption of the canine teeth, causing the cervical enamel margin to extend beyond the alveolar bone and exposing the root, occurs with age and growth in...
Pronounced over-eruption of the canine teeth, causing the cervical enamel margin to extend beyond the alveolar bone and exposing the root, occurs with age and growth in Australian marsupial carnivores, much more than in eco-morphologically equivalent placental carnivores. Suppression of functional tooth replacement is characteristic of marsupials, where most placentals have the primitive diphyodont pattern of two generations of incisor, canine and premolar teeth. Canine and molar tooth dimensions of four species of marsupial carnivores (thylacine , Tasmanian devil and two quolls spp) and canine dimensions of seven eco-morphologically equivalent placental carnivore species were measured from museum specimens. Canine dimensions were measured in a time series on live wild-living individual devils and quolls. The canine teeth and to a lesser extent the molar teeth of marsupial carnivores continue to erupt through life, resulting in a net increase in tooth height and diameter, a phenomenon not evident in placental carnivores. Potential mechanisms causing over-eruption include tooth wear and gradual release of occlusal pressure as the individual grows. Over-eruption in marsupial carnivores may be a compensatory response for tooth size limits imposed by monophyodont tooth replacement, ensuring that animal's teeth are scaled to jaw size from juvenile to adulthood.
Topics: Pregnancy; Animals; Female; Marsupialia; Australia; Placenta; Odontogenesis
PubMed: 38087924
DOI: 10.1098/rspb.2023.0644 -
International Journal of Oral Science Dec 2023Ameloblasts are specialized cells derived from the dental epithelium that produce enamel, a hierarchically structured tissue comprised of highly elongated...
Ameloblasts are specialized cells derived from the dental epithelium that produce enamel, a hierarchically structured tissue comprised of highly elongated hydroxylapatite (OHAp) crystallites. The unique function of the epithelial cells synthesizing crystallites and assembling them in a mechanically robust structure is not fully elucidated yet, partly due to limitations with in vitro experimental models. Herein, we demonstrate the ability to generate mineralizing dental epithelial organoids (DEOs) from adult dental epithelial stem cells (aDESCs) isolated from mouse incisor tissues. DEOs expressed ameloblast markers, could be maintained for more than five months (11 passages) in vitro in media containing modulators of Wnt, Egf, Bmp, Fgf and Notch signaling pathways, and were amenable to cryostorage. When transplanted underneath murine kidney capsules, organoids produced OHAp crystallites similar in composition, size, and shape to mineralized dental tissues, including some enamel-like elongated crystals. DEOs are thus a powerful in vitro model to study mineralization process by dental epithelium, which can pave the way to understanding amelogenesis and developing regenerative therapy of enamel.
Topics: Mice; Animals; Durapatite; Dental Enamel; Ameloblasts; Amelogenesis; Stem Cells; Organoids
PubMed: 38062012
DOI: 10.1038/s41368-023-00257-w -
Development (Cambridge, England) Dec 2023Most vertebrate species undergo tooth replacement throughout adult life. This process is marked by the shedding of existing teeth and the regeneration of tooth organs....
Most vertebrate species undergo tooth replacement throughout adult life. This process is marked by the shedding of existing teeth and the regeneration of tooth organs. However, little is known about the genetic circuitry regulating tooth replacement. Here, we tested whether fish orthologs of genes known to regulate mammalian hair regeneration have effects on tooth replacement. Using two fish species that demonstrate distinct modes of tooth regeneration, threespine stickleback (Gasterosteus aculeatus) and zebrafish (Danio rerio), we found that transgenic overexpression of four different genes changed tooth replacement rates in the direction predicted by a hair regeneration model: Wnt10a and Grem2a increased tooth replacement rate, whereas Bmp6 and Dkk2 strongly inhibited tooth formation. Thus, similar to known roles in hair regeneration, Wnt and BMP signals promote and inhibit regeneration, respectively. Regulation of total tooth number was separable from regulation of replacement rates. RNA sequencing of stickleback dental tissue showed that Bmp6 overexpression resulted in an upregulation of Wnt inhibitors. Together, these data support a model in which different epithelial organs, such as teeth and hair, share genetic circuitry driving organ regeneration.
Topics: Animals; Zebrafish; Tooth; Odontogenesis; Animals, Genetically Modified; Smegmamorpha; Mammals
PubMed: 38059590
DOI: 10.1242/dev.202168 -
Journal of Dental Research Jan 2024Amelogenesis imperfecta (AI) comprises a group of rare, inherited disorders with abnormal enamel formation. Ameloblastin (AMBN), the second most abundant enamel matrix...
Amelogenesis imperfecta (AI) comprises a group of rare, inherited disorders with abnormal enamel formation. Ameloblastin (AMBN), the second most abundant enamel matrix protein (EMP), plays a critical role in amelogenesis. Pathogenic biallelic loss-of-function variants are known to cause recessive hypoplastic AI. A report of a family with dominant hypoplastic AI attributed to AMBN missense change p.Pro357Ser, together with data from animal models, suggests that the consequences of variants in human AI remain incompletely characterized. Here we describe 5 new pathogenic variants in 11 individuals with AI. These fall within 3 groups by phenotype. Group 1, consisting of 6 families biallelic for combinations of 4 different variants, have yellow hypoplastic AI with poor-quality enamel, consistent with previous reports. Group 2, with 2 families, appears monoallelic for a variant shared with group 1 and has hypomaturation AI of near-normal enamel volume with pitting. Group 3 includes 3 families, all monoallelic for a fifth variant, which are affected by white hypoplastic AI with a thin intact enamel layer. Three variants, c.209C>G; p.(Ser70*) (groups 1 and 2), c.295T>C; p.(Tyr99His) (group 1), and c.76G>A; p.(Ala26Thr) (group 3) were identified in multiple families. Long-read locus sequencing revealed these variants are on the same conserved haplotype, implying they originate from a common ancestor. Data presented therefore provide further support for possible dominant as well as recessive inheritance for -related AI and for multiple contrasting phenotypes. In conclusion, our findings suggest pathogenic variants have a more complex impact on human AI than previously reported.
Topics: Animals; Humans; Amelogenesis; Amelogenesis Imperfecta; Dental Enamel Proteins; Pedigree; Phenotype
PubMed: 38058155
DOI: 10.1177/00220345231203694 -
Clinical and Experimental Dental... Feb 2024Migration and differentiation of human dental pulp stem cells (hDPSCs) is a vital and key factor in the success of reparative dentin formation for maintenance of pulp...
OBJECTIVES
Migration and differentiation of human dental pulp stem cells (hDPSCs) is a vital and key factor in the success of reparative dentin formation for maintenance of pulp vitality. Pulp capping materials are used to stimulate DPSCs to induce new dentin formation. Thus, the aim of the present study was to compare the response of DPSCs to four commercially available pulp capping materials: a bioactive bioceramic (Material 1), a nonresinous ready-to-use bioceramic cement (Material 2), a bioactive composite (Material 3), and a biocompatible, dual-cured, resin-modified calcium silicate (Material 4).
MATERIALS AND METHODS
hDPSCs were isolated and cultured from freshly extracted teeth and were then characterized by flow cytometry and multilineage differentiation. Discs prepared from pulp capping materials were tested with hDPSCs and MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay, cell migration assay and odontogenic differentiation assay was performed. Expression of osteogenic markers (osteopontin, RUNX family transcription factor 2, osteocalcin) and the odontogenic marker (dentin sialophosphoprotein) was detected using reverse transcription-polymerase chain reaction.
RESULTS
Materials 1, 2, and 3 generated more cell viability than Material 4. Furthermore, Material 4 showed the least wound exposure percentage, while Material 3 showed the highest percentage. Enhanced mineralization was found in hDSCPs cultured with Material 3, followed by Material 1, and then Material 2, while Material 4 revealed the least calcified mineralization.
CONCLUSIONS
The results of this study were inconclusive regards contemporary bioceramic materials designed for vital pulp therapy as they have different effects on hDPSC. Further testing for cytotoxicity using live-dead staining, animal experiments, clinical trials, and independent analyses of these biomaterials is necessary for clinicians to make an informed decision for their use.
Topics: Animals; Humans; Dental Pulp; Dental Pulp Capping; Odontogenesis; Cell Differentiation; Stem Cells
PubMed: 38053499
DOI: 10.1002/cre2.816 -
Journal of Oral and Maxillofacial... 2023The process of odontogenesis is complex involving epithelial-mesenchymal interactions, along with the molecular signalling pathways triggering the initiating process....
BACKGROUND
The process of odontogenesis is complex involving epithelial-mesenchymal interactions, along with the molecular signalling pathways triggering the initiating process. The triggering factors and cells precisely involved in the pathogenesis of odontogenic cysts and tumors are unknown. There is a vast array of biomarkers used to stain different sites, thereby helpful in diagnosing and evaluating the prognosis of these cysts and tumors. In the following study, Anti Apoptotic survivin expression patterns were assessed quantitatively in 48 samples (12 each) of Reduced Enamel Epithelium, Adenomatoid Odontogenic Tumor, Odontogenic Keratocyst and Ameloblastoma.
AIM
The Aim of this study is to assess the anti-apoptotic survivin expression in Reduced Enamel Epithelium, Adenomatoid odontogenic tumour, Odontogenic Keratocyst and Ameloblastoma.
MATERIALS AND METHODS
The present study is carried out with 12 samples in each group. Routine hematoxylin and eosin staining was performed for confirmatory diagnosis. Later Immunohistochemistry was performed using survivin antibody. Survivin protein expression was analyzed using the parameters like location, intensity, percentage of cells positivity with survivin protein and extent of staining. With the help of Olympus BX 43 microscope, with ProgRes microscope camera, the 48 slides obtained were examined. The region of interest was selected in each slide and number of cells positively stained was counted. Data was analyzed using SPSS software version 23. Descriptive for scale data, results were analysed by using ANOVA with Chi-square test for intergroup comparison.
RESULTS
The results showed significant P value <0.05. Expression of survivin was highest in Ameloblastoma, followed by Odontogenic keratocyst, Adenomatoid odontogenic tumor, and Reduced Enamel Epithelium.
CONCLUSION
Survivin was involved in the inhibition of apoptosis as well as the detailed understanding of the biological behaviour of odontogenic cysts and tumours, thereby increasing therapeutic approaches.
PubMed: 38033952
DOI: 10.4103/jomfp.jomfp_446_22 -
International Journal of Oral Science Nov 2023Tooth root development involves intricate spatiotemporal cellular dynamics and molecular regulation. The initiation of Hertwig's epithelial root sheath (HERS) induces... (Review)
Review
Tooth root development involves intricate spatiotemporal cellular dynamics and molecular regulation. The initiation of Hertwig's epithelial root sheath (HERS) induces odontoblast differentiation and the subsequent radicular dentin deposition. Precisely controlled signaling pathways modulate the behaviors of HERS and the fates of dental mesenchymal stem cells (DMSCs). Disruptions in these pathways lead to defects in root development, such as shortened roots and furcation abnormalities. Advances in dental stem cells, biomaterials, and bioprinting show immense promise for bioengineered tooth root regeneration. However, replicating the developmental intricacies of odontogenesis has not been resolved in clinical treatment and remains a major challenge in this field. Ongoing research focusing on the mechanisms of root development, advanced biomaterials, and manufacturing techniques will enable next-generation biological root regeneration that restores the physiological structure and function of the tooth root. This review summarizes recent discoveries in the underlying mechanisms governing root ontogeny and discusses some recent key findings in developing of new biologically based dental therapies.
Topics: Female; Humans; Tooth Root; Odontogenesis; Epithelial Cells; Cell Differentiation; Biocompatible Materials
PubMed: 38001110
DOI: 10.1038/s41368-023-00258-9 -
ELife Nov 2023The role of regulated cell death in organ development, particularly the impact of non-apoptotic cell death, remains largely uncharted. Ferroptosis, a non-apoptotic cell...
The role of regulated cell death in organ development, particularly the impact of non-apoptotic cell death, remains largely uncharted. Ferroptosis, a non-apoptotic cell death pathway known for its iron dependence and lethal lipid peroxidation, is currently being rigorously investigated for its pathological functions. The balance between ferroptotic stress (iron and iron-dependent lipid peroxidation) and ferroptosis supervising pathways (anti-lipid peroxidation systems) serves as the key mechanism regulating the activation of ferroptosis. Compared with other forms of regulated necrotic cell death, ferroptosis is critically related to the metabolism of lipid and iron which are also important in organ development. In our study, we examined the role of ferroptosis in organogenesis using an ex vivo tooth germ culture model, investigating the presence and impact of ferroptotic stress on tooth germ development. Our findings revealed that ferroptotic stress increased during tooth development, while the expression of glutathione peroxidase 4 (Gpx4), a crucial anti-lipid peroxidation enzyme, also escalated in dental epithelium/mesenchyme cells. The inhibition of ferroptosis was found to partially rescue erastin-impaired tooth morphogenesis. Our results suggest that while ferroptotic stress is present during tooth organogenesis, its effects are efficaciously controlled by the subsequent upregulation of Gpx4. Notably, an overabundance of ferroptotic stress, as induced by erastin, suppresses tooth morphogenesis.
Topics: Odontogenesis; Organogenesis; Ferroptosis; Lipid Peroxidation; Iron
PubMed: 37991825
DOI: 10.7554/eLife.88745 -
Frontiers in Bioscience (Landmark... Oct 2023Dental pulp stem cells (DPSCs) are a type of mesenchymal stem cells derived from dental pulp that serves as an important model for investigating biological regeneration.... (Review)
Review
Dental pulp stem cells (DPSCs) are a type of mesenchymal stem cells derived from dental pulp that serves as an important model for investigating biological regeneration. DPSCs have a multipotent differentiation capacity and can promote different biological processes, including osteogenesis, odontogenesis, chondrogenesis, and angiogenesis. These biological processes are regulated by an extensive range of intra- and extra-cellular factors. Further, biomechanical cues, such as substrate stiffness, physical stress, and cell spreading, have been highlighted as particularly important modulators of DPSC function. This review sought to discuss various related signaling components involved in biomechanical cues and their respective roles in cellular and tissue responses in DPSCs, summarize current findings, and provide an outlook on the potential applications of biomechanics in regenerative medicine and tissue engineering.
Topics: Stem Cells; Dental Pulp; Cell Differentiation; Osteogenesis; Mesenchymal Stem Cells; Cells, Cultured; Cell Proliferation
PubMed: 37919075
DOI: 10.31083/j.fbl2810274