Project description:Dental pulp plays a crucial role for dental health, and dental pulp aging influences their regenerative and reparative function. However, the underlying molecular mechanisms of dental pulp aging are not exhaustively understood, and thereby an in-depth and complete understanding of the aged dental pulp is of foremost importance. This study aimed to explore the heterogeneity of young and aged dental pulp tissue using single-cell RNA sequencing (scRNA-seq).
Project description:Postnatal cell fate has been postulated to be primarily determined by the local tissue microenvironment. Here, we found that Mediator 1 (Med1) dependent epigenetic mechanisms dictate tissue-specific lineage commitment and progression of dental epithelia. Deletion of Med1, a key component of the Mediator complex linking enhancer activities to gene transcription, provokes a tissue extrinsic lineage shift, causing hair generation in the dental environment. Med1 deficiency gives rise to unusual hair growth via primitive cellular aggregates on incisors. Mechanistically, we found that Med1 establishes super-enhancers that control enamel lineage transcription factors in dental stem cells and their progenies. However, Med1 deficiency reshapes the enhancer landscapes and causes a switch from the dental epithelial transcriptional program towards hair and epidermis on incisors in vivo, and in dental epithelial stem cells in vitro. Med1 loss also provokes an increase in the number and size of enhancers. Interestingly, control dental epithelia already exhibit enhancers for hair and epidermal key transcription factors; these expand in size and transform into super-enhancers upon Med1 loss suggesting that these epigenetic mechanisms cause the transcriptomic and phenotypic shift towards epidermal and hair lineages. Thus, we propose a role for Med1 in safeguarding lineage specific enhancers, highlight the central role of enhancer accessibility and usage in lineage reprogramming and provide new insights into ectodermal regeneration. Duplicate Chip-seq for dental tisses from head region of cervical loop (CLH) containing dental epithelial stem cells and tail region (CLT) including progenies that were dissected from mandible of 4 week old conditional Krt14CreMed1 knockout (cKO) mice or littermate control (Ctrl) mice. Chip-seq was conducted by using antibodies against Mediator 1 (Med1) and H3K27ac (H3).
Project description:Cell fate is defined by specific transcriptional program. Here, we provide evidence that the transcriptional coactivator, Mediator 1 (MED1), is critical in determining the cell fate of ectodermal epithelia. MED1 ablation disrupted enamel formation and generated hair adjacent to the incisors. Deletion of MED1 altered the differentiation of dental epithelia to one expressing epidermal and hair genes similar to the skin. The cellular switch from dental to epidermal/hair lineage was characterized by abnormalities in MED1 deficient dental epithelial stem cells residing in cervical loop. MED1 deficiency caused a failure of dental epithelial stem cells to commit to the dental stratum intermedium regulated by Notch signaling. Instead, MED1 deficient cells retained stem cell potentials expressing Sox2. These cells were eventually adopted an epidermal fate probably through calcium provided through capillary networks, which is originally utilized for enamel formation. Our results demonstrate that MED1 regulates Sox2/Notch1 regulated cell lineage determination in dental epithelia. Our study also shows a potential to regenerate hairs by using genetically engineered dental tissues or cells outside of the skin. n=3 WT and KO (each sample contain dissected dental tissues from 3 mice combined)
Project description:Cell fate is defined by specific transcriptional program. Here, we provide evidence that the transcriptional coactivator, Mediator 1 (MED1), is critical in determining the cell fate of ectodermal epithelia. MED1 ablation disrupted enamel formation and generated hair adjacent to the incisors. Deletion of MED1 altered the differentiation of dental epithelia to one expressing epidermal and hair genes similar to the skin. The cellular switch from dental to epidermal/hair lineage was characterized by abnormalities in MED1 deficient dental epithelial stem cells residing in cervical loop. MED1 deficiency caused a failure of dental epithelial stem cells to commit to the dental stratum intermedium regulated by Notch signaling. Instead, MED1 deficient cells retained stem cell potentials expressing Sox2. These cells were eventually adopted an epidermal fate probably through calcium provided through capillary networks, which is originally utilized for enamel formation. Our results demonstrate that MED1 regulates Sox2/Notch1 regulated cell lineage determination in dental epithelia. Our study also shows a potential to regenerate hairs by using genetically engineered dental tissues or cells outside of the skin. n=4 WT and KO (each group contains dissected dental tissues from 3 mice combined)
Project description:Cell fate is defined by specific transcriptional program. Here, we provide evidence that the transcriptional coactivator, Mediator 1 (MED1), is critical in determining the cell fate of ectodermal epithelia. MED1 ablation disrupted enamel formation and generated hair adjacent to the incisors. Deletion of MED1 altered the differentiation of dental epithelia to one expressing epidermal and hair genes similar to the skin. The cellular switch from dental to epidermal/hair lineage was characterized by abnormalities in MED1 deficient dental epithelial stem cells residing in cervical loop. MED1 deficiency caused a failure of dental epithelial stem cells to commit to the dental stratum intermedium regulated by Notch signaling. Instead, MED1 deficient cells retained stem cell potentials expressing Sox2. These cells were eventually adopted an epidermal fate probably through calcium provided through capillary networks, which is originally utilized for enamel formation. Our results demonstrate that MED1 regulates Sox2/Notch1 regulated cell lineage determination in dental epithelia. Our study also shows a potential to regenerate hairs by using genetically engineered dental tissues or cells outside of the skin. n=3 WT and KO (each sample contain dissected dental tissues from 3 mice combined)
Project description:Transcriptional profiling of Bmi1 mutant dental epithelia including the stem cell compartment to determine which genes are upregulated in response to loss of Bmi1. Two condition experiment: dental epithelia homozygous null for Bmi1 and WT dental epithelia. 4 replicates each
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.