Transcriptomic profiling of the adult reptilian dentition sheds light on the genes regulating indefinite tooth replacement
Ontology highlight
ABSTRACT:
ORGANISM(S): Eublepharis macularius
PROVIDER: GSE220653 | GEO | 2022/12/24
REPOSITORIES: GEO
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Project description:The aim of this study is to discover new genes and cells involved in life-long tooth replacement. Here we study the adult dentition of the leopard gecko (Eublepharis macularius). Bulk RNAseq was used to compare teeth that are in function versus unerupted, developing teeth and single cell RNA-seq was carried out on jaw segments containing the dental forming tissues. In bulk RNAseq data, we found that functional teeth expressed genes involved in bone and tooth resorption. Indeed, we found expression of these markers in multinucleated odontoclasts within resorbing functional teeth. Chemotaxis genes SEMA3A and SEMA3E, were expressed within odontoblasts and in adjacent mesenchyme using RNAscope. Semaphorins could be involved in regulating odontoclast formation, recruitment or repulsion from developing teeth. The scRNA-seq experiment successfully isolated dental mesenchyme and several epithelial clusters. We confirmed that some of these genes are expressed in the earliest tooth buds within the tooth forming field and in erupting teeth. This work will lead to discovery of genes and cell populations that may have been gained or lost during evolution of amniotes. Moreover, gene differences may lead to dental therapies to prevent tooth loss from disease or injury.
2022-12-24 | GSE221110 | GEO
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).
2022-07-01 | GSE198580 | GEO
Project description:During embryonic organogenesis, the odontogenic potential resides in dental mesenchyme from the bud stage until birth. Mouse dental mesenchymal cells (mDMCs) isolated from the inductive dental mesenchyme of developing molars are frequently used in the context of tooth development and regeneration. cultured mDMCs could retain the odontogenic potential for 24 h with a ratio of 60% for tooth formation, but mDMCs were incapable of supporting tooth formation after more than 24 h in culture. To reveal the underlying mechanism of the impairment of odontogenic potential, we generated gene expression profiles from mDMCs in culture using RNA-seq.
2016-10-31 | GSE78228 | GEO
Project description:In this study, using mouse molar as the model, we developed a dual fluorescence reporter mouse to precisely track and analyze dental epithelium and mesenchyme at single-cell resolution from early embryonic to postnatal stages. Moreover, we constructed the virtual molar explorer (VMEx) to spatially map 15,967 molar-expressed genes and identified that Msx1+ Sdc1+ marked the developing dental papilla while surrounded by Msx1+ Sdc1- molar niche. Through tooth germ reconstitution and organoid culture in vitro and kidney capsule transplantation in vivo, we provided evidence that the Msx1+ Sdc1- dental follicle cells might function as the tooth organizers that promoted epithelium survival and tooth germ organization. Furthermore, the appearance of Msx1+ Sdc1+ dental papilla cells relied on the interaction between dental epithelium and Msx1+ Sdc1- dental follicle cells. Together, our results revealed the cellular dynamics of tooth development in mice and identified that the dental follicle might be the key driver of epithelial-mesenchymal interaction and tooth morphogenesis.
2022-11-01 | GSE162413 | GEO
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.
2023-04-19 | E-MTAB-12544 | biostudies-arrayexpress
Project description:Previous studies have suggested that Bmp4 is a key Msx1-dependent mesenchymal odontogenic signal for driving tooth morphogenesis through the bud-to-cap transition. Whereas the bud stage tooth developmental arrest in Msx1-/- mutant mice was accompanied by reduction in mesenchymal Bmp4 mRNA expression, we show that depleting functional Bmp4 mRNAs in the tooth mesenchyme, through neural crest-specific gene inactivation in Bmp4f/f;Wnt1Cre mice, caused mandibular molar developmental arrest at the bud stage but allowed maxillary molars and incisors to develop to mineralized teeth. We show that the Wnt inhibitors Dkk2 and Wif1 were much more abundantly expressed in the mandibular than maxillary molar mesenchyme in wildtype embryos and that Dkk2 expression was significantly unregulated in the tooth mesenchyme in Bmp4f/f;Wnt1Cre embryos. In addition, expression of Osr2, which encodes a zinc finger protein that antagonizes Msx1-mediated activation of odontogenic mesenchyme, is significantly upregulated in the molar mesenchyme in Bmp4f/f;Wnt1Cre embryos. Msx1 heterozygosity enhanced maxillary molar developmental defects whereas Osr2 heterozygosity rescued mandibular first molar morphogenesis in Bmp4f/f;Wnt1Cre mice. Moreover, in contrast to complete lack of supernumerary tooth initiation in Msx1-/-Osr2-/- mutant mice, Osr2-/-Bmp4f/f;Wnt1Cre compound mutant mice exhibit formation and subsequent arrest of supernumerary tooth germs that correlated with down regulation of Msx1 expression in the tooth mesenchyme. Taken together, our data indicate that, while reduction in mesenchymal Bmp4 expression alone could not account for the tooth bud arrest phenotype in Msx1-/- mutant mice, Bmp4 signaling synergizes with Msx1 and antagonizes Osr2 to activate mesenchymal odontogenic activity to drive tooth morphogenesis and sequential tooth formation. E13.5 mouse embryos tooth germs were microdissected by laser capture microdissection (LCM), and the mandibular molar and maxillary molar were separated. 3 pairs of control and mutant samples were pooled for the RNA extraction.
2013-01-22 | E-GEOD-39918 | biostudies-arrayexpress
Project description:Transforming growth factor (TGF) plays an important role in tooth morphogenesis and mineralization. During postnatal development, the dental pulp (DP) mesenchyme secretes neurotrophic factors that guide trigeminal nerve fibers into and throughout the DP. This process is tightly linked with dentin formation and mineralization. Our laboratory established a mouse model in which Tgfbr2 was conditionally deleted in DP mesenchyme using an Osterix promoter-driven Cre recombinase (Tgfbr2cko). These mice survived postnatally with significant defects in bones and teeth, including reduced mineralization and short roots. Hematoxylin and eosin staining revealed reduced axon-like structures in the mutant mice. Reporter imaging demonstrated that Osterix-Cre activity within the tooth was active in the DP and derivatives, but not in neurons. Immunofluorescence staining for 3 tubulin (neuronal marker) was performed on serial cryosections from control and mutant molars on postnatal days 7 and 24 (P7, P24). Confocal imaging and pixel quantification demonstrated reduced innervation in Tgfbr2cko first molars at both stages compared to controls, indicating that signals necessary to promote neurite outgrowth were disrupted by Tgfbr2 deletion. We performed mRNA-Sequence (RNA-Seq) and gene onotology analyses using RNA from the DP of P7 control and mutant mice to investigate the pathways involved in Tgfbr2-mediated tooth development. These analyses identified downregulation of several mineralization-related and neuronal genes in the Tgfbr2cko DP compared to controls. Select gene expression patterns were confirmed by quantitative real-time PCR and immunofluorescence imaging. Lastly, trigeminal neurons were co-cultured atop Transwell filters overlying primary Tgfbr2f/f DP cells. Tgfbr2 in the DP was deleted via adenovirus-expressed Cre recombinase. Confocal imaging of axons through the filter pores showed increased axonal sprouting from neurons cultured with Tgfbr2-positive DP cells compared to neurons cultured alone. Axon sprouting was reduced when Tgfbr2 was knocked down in the DP cells. Immunofluorescence of dentin sialophosphoprotein in co-cultured DP cells confirmed reduced mineralization potential in cells with Tgfbr2 deletion. Both our proteomics and RNA-Seq analyses indicate that axonal guidance cues, particularly semaphorin signaling, were disrupted by Tgfbr2 deletion. Thus, Tgfbr2 in the DP mesenchyme appears to regulate differentiation and the cells’ ability to guide neurite outgrowth during tooth mineralization and innervation.
2022-02-04 | PXD031046 | Pride
Project description:Tooth development is a complex process orchestrated by intricate gene regulatory networks, involving both odontogenic epithelium and ectomesenchyme. Six1, a pivotal transcription factor (TF), is involved in the development of the lower incisor. However, its precise role during incisor development and the molecular mechanisms underpinning its regulatory functions remain poorly understood. This study employs Six1 deletion mouse models to elucidate the critical regulatory role of Six1 in governing dental mesenchyme development. By performing single-cell RNA sequencing (scRNA-seq), we constructed a comprehensive transcriptome atlas of tooth germ development from the bud to bell stage. Our analyses suggest that the dental follicle (DF) and the dental papilla (DP) are differentiated from dental ectomesenchyme (DEM), and identify the key transcription factors (TFs) underlying these distinct states. Notably, we show that Dlx1, Dlx2, and Dlx5 (Dlx1/2/5) may function as the key TFs that promote the formation of DP. We further show that the deletion of Six1 perturbs dental mesenchyme development by impeding the transitions from DEM to DP states. Importantly, SIX1 directly binds to the promoters of Dlx1/2/5 to promote their co-expression, which subsequently leads to widespread epigenetic and transcriptional remodeling. In summary, our findings unveil Six1's indispensable role in incisor development, offering key insights into transcription factor-driven regulatory networks that govern dental mesenchyme cell fate transitions during tooth development.
2024-05-06 | GSE254482 | GEO
Project description:Tooth development is a complex process orchestrated by intricate gene regulatory networks, involving both odontogenic epithelium and ectomesenchyme. Six1, a pivotal transcription factor (TF), is involved in the development of the lower incisor. However, its precise role during incisor development and the molecular mechanisms underpinning its regulatory functions remain poorly understood. This study employs Six1 deletion mouse models to elucidate the critical regulatory role of Six1 in governing dental mesenchyme development. By performing single-cell RNA sequencing (scRNA-seq), we constructed a comprehensive transcriptome atlas of tooth germ development from the bud to bell stage. Our analyses suggest that the dental follicle (DF) and the dental papilla (DP) are differentiated from dental ectomesenchyme (DEM), and identify the key transcription factors (TFs) underlying these distinct states. Notably, we show that Dlx1, Dlx2, and Dlx5 (Dlx1/2/5) may function as the key TFs that promote the formation of DP. We further show that the deletion of Six1 perturbs dental mesenchyme development by impeding the transitions from DEM to DP states. Importantly, SIX1 directly binds to the promoters of Dlx1/2/5 to promote their co-expression, which subsequently leads to widespread epigenetic and transcriptional remodeling. In summary, our findings unveil Six1's indispensable role in incisor development, offering key insights into transcription factor-driven regulatory networks that govern dental mesenchyme cell fate transitions during tooth development.
2024-05-06 | GSE254658 | GEO
Project description:The RSK2 gene is responsible for Coffin-Lowry syndrome, an X-linked monogenic disease associating severe learning deficit andassociated to typical facial and digital abnormalities and skeletal changes. Craniofacial and dental anomalies encountered in this rare disease have been poorly characterized. In this study we explore, through X-Ray microtomographic analysis, the variable craniofacial dysmorphism and dental anomalies present in Rsk2 knockout mice, an animal model of Coffin-Lowry syndrome, as well as in triple Rsk1,2,3 knockout mutants. We report in these mutants the occurrence of a surpernumerary tooth mesial to the first molar. This highly penetrant phenotype is considered as a remnant of evolutionary lost teeth. This possibly leads to the significant reduction of the maxillary diastema. Abnormalities of molar shape were almost restricted to the mesial part of both upper and lower first molars (M1). We also report an expression analysis of the four Rsk genes (Rsk1, 2, 3 and 4) at various stages of odontogenesis in wild-type (WT) mice. Rsk2 was mainly expressed in the mesenchymal, neural crest derived compartment, correlating with proliferative areas of the developing teeth and consistent with a biological function of RSK2 in cell cycle control and cell growth, which when invalidated could be responsible for the dental phenotype. In an attempt to unravel the molecular pathways involved in the genesis of these dental defects, we performed a comparative transcriptomic (DNA microarray) analysis of mandibular wild-type versus Rsk2-/Y molars, and further demonstrated a misregulation of selected genes, using a Rsk2 shRNA knock-down strategy in molar tooth germs cultured in vitro.
2014-01-13 | E-GEOD-51034 | biostudies-arrayexpress