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Jing J, Zhang M, Guo T, Pei F, Yang Y, Chai Y. Rodent incisor as a model to study mesenchymal stem cells in tissue homeostasis and repair. FRONTIERS IN DENTAL MEDICINE 2022. [DOI: 10.3389/fdmed.2022.1068494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022] Open
Abstract
The homeostasis of adult tissues, such as skin, hair, blood, and bone, requires continuous generation of differentiated progeny of stem cells. The rodent incisor undergoes constant renewal and can provide an extraordinary model for studying stem cells and their progeny in adult tissue homeostasis, cell differentiation and injury-induced regeneration. Meanwhile, cellular heterogeneity in the mouse incisor also provides an opportunity to study cell-cell communication between different cell types, including interactions between stem cells and their niche environment. More importantly, the molecular and cellular regulatory mechanisms revealed by the mouse incisor have broad implications for other organs. Here we review recent findings and advances using the mouse incisor as a model, including perspectives on the heterogeneity of cells in the mesenchyme, the niche environment, and signaling networks that regulate stem cell behavior. The progress from this field will not only expand the knowledge of stem cells and organogenesis, but also bridge a gap between animal models and tissue regeneration.
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2
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Doke T, Huang S, Qiu C, Sheng X, Seasock M, Liu H, Ma Z, Palmer M, Susztak K. Genome-wide association studies identify the role of caspase-9 in kidney disease. SCIENCE ADVANCES 2021; 7:eabi8051. [PMID: 34739325 PMCID: PMC8570608 DOI: 10.1126/sciadv.abi8051] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 09/16/2021] [Indexed: 06/13/2023]
Abstract
Genome-wide association studies (GWAS) have identified hundreds of genetic risk regions for kidney dysfunction [estimated glomerular filtration rate (eGFR)]; however, the causal genes, cell types, and pathways are poorly understood. Integration of GWAS and human kidney expression of quantitative trait analysis using Bayesian colocations, transcriptome-wide association studies, and summary-based Mendelian randomization studies prioritized caspase-9 (CASP9) as a kidney disease risk gene. Human kidney single-cell epigenetic and immunostaining studies indicated kidney tubule cells as a disease-causing cell type. Mice with genetic deletion or pharmacological inhibition of CASP9 showed lower apoptosis while having improved mitophagy, resulting in dampened activation of cytosolic nucleotide sensing pathways (cGAS-STING), reduction of inflammation, and protection from acute kidney disease or renal fibrosis. In summary, here, we prioritized CASP9 as an eGFR GWAS target gene and demonstrated the causal role of CASP9 in kidney disease development via improving mitophagy and lowering inflammation and apoptosis.
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Affiliation(s)
- Tomohito Doke
- Renal Electrolyte and Hypertension Division, Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Shizheng Huang
- Renal Electrolyte and Hypertension Division, Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Chengxiang Qiu
- Renal Electrolyte and Hypertension Division, Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Xin Sheng
- Renal Electrolyte and Hypertension Division, Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Matthew Seasock
- Renal Electrolyte and Hypertension Division, Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Hongbo Liu
- Renal Electrolyte and Hypertension Division, Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Ziyuan Ma
- Renal Electrolyte and Hypertension Division, Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Matthew Palmer
- Department of Pathology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Katalin Susztak
- Renal Electrolyte and Hypertension Division, Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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Gan L, Liu Y, Cui DX, Pan Y, Wan M. New insight into dental epithelial stem cells: Identification, regulation, and function in tooth homeostasis and repair. World J Stem Cells 2020; 12:1327-1340. [PMID: 33312401 PMCID: PMC7705464 DOI: 10.4252/wjsc.v12.i11.1327] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 08/21/2020] [Accepted: 09/15/2020] [Indexed: 02/06/2023] Open
Abstract
Tooth enamel, a highly mineralized tissue covering the outermost area of teeth, is always damaged by dental caries or trauma. Tooth enamel rarely repairs or renews itself, due to the loss of ameloblasts and dental epithelial stem cells (DESCs) once the tooth erupts. Unlike human teeth, mouse incisors grow continuously due to the presence of DESCs that generate enamel-producing ameloblasts and other supporting dental epithelial lineages. The ready accessibility of mouse DESCs and wide availability of related transgenic mouse lines make mouse incisors an excellent model to examine the identity and heterogeneity of dental epithelial stem/progenitor cells; explore the regulatory mechanisms underlying enamel formation; and help answer the open question regarding the therapeutic development of enamel engineering. In the present review, we update the current understanding about the identification of DESCs in mouse incisors and summarize the regulatory mechanisms of enamel formation driven by DESCs. The roles of DESCs during homeostasis and repair are also discussed, which should improve our knowledge regarding enamel tissue engineering.
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Affiliation(s)
- Lu Gan
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Department of Pediatric Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, Sichuan Province, China
| | - Ying Liu
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Department of Pediatric Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, Sichuan Province, China
| | - Di-Xin Cui
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Department of Pediatric Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, Sichuan Province, China
| | - Yue Pan
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Department of Pediatric Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, Sichuan Province, China
| | - Mian Wan
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, Sichuan Province, China
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4
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Exploiting teeth as a model to study basic features of signaling pathways. Biochem Soc Trans 2020; 48:2729-2742. [DOI: 10.1042/bst20200514] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 10/06/2020] [Accepted: 10/08/2020] [Indexed: 12/21/2022]
Abstract
Teeth constitute a classical model for the study of signaling pathways and their roles in mediating interactions between cells and tissues in organ development, homeostasis and regeneration. Rodent teeth are mostly used as experimental models. Rodent molars have proved fundamental in the study of epithelial–mesenchymal interactions and embryonic organ morphogenesis, as well as to faithfully model human diseases affecting dental tissues. The continuously growing rodent incisor is an excellent tool for the investigation of the mechanisms regulating stem cells dynamics in homeostasis and regeneration. In this review, we discuss the use of teeth as a model to investigate signaling pathways, providing an overview of the many unique experimental approaches offered by this organ. We discuss how complex networks of signaling pathways modulate the various aspects of tooth biology, and the models used to obtain this knowledge. Finally, we introduce new experimental approaches that allow the study of more complex interactions, such as the crosstalk between dental tissues, innervation and vascularization.
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Xiao X, Mo H, Tu K. CTNNB1 mutation suppresses infiltration of immune cells in hepatocellular carcinoma through miRNA-mediated regulation of chemokine expression. Int Immunopharmacol 2020; 89:107043. [PMID: 33039961 DOI: 10.1016/j.intimp.2020.107043] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 08/06/2020] [Accepted: 09/22/2020] [Indexed: 02/06/2023]
Abstract
Mutations in the CTNNB1 gene in hepatocellular carcinoma (HCC) are related to immune exclusion, and HCC patients with CTNNB1 mutations tend to be primarily resistant to anti-PD1 therapy. However, systemic evaluation of immune cell infiltration in HCC with mutant CTNNB1 is lacking, and the mechanism of immune exclusion resulting from CTNNB1 mutations remains unclear. Based on CTNNB1 mutation status in HCC, we investigated RNA and miRNA expression and infiltration of immune cells. Data downloaded from TCGA showed that HCC with CTNNB1 mutation had an increased expression of CTNNB1. HCC with CTNNB1 mutation showed a reduction in infiltration score as well as in abundance of certain kinds of immune cells, including CD4 naïve T cells, CD4+ T cells, Tex cells, Th2 cells, Tfh cells, B cells, macrophages, and NK cells. Furthermore, there were 13 chemokines downregulated among all the 14 differentially expressed chemokines (DE-CKs) in CTNNB1 mutants compared to those in the wild type. A positive correlation was found between the expression of DE-CKs and infiltration score, as well as infiltration level of 6 types of immune cells, namely B cells, CD8+ cells, CD4+ cells, macrophages, neutrophils, and dendritic cells. Additionally, 302 differentially expressed immune-related genes (DE-IRGs) were involved mainly in the human immune response and cytokine-cytokine receptor interaction. The target DE-IRGs of differentially expressed miRNAs (DE-miRNAs) were identified and used to construct a network with DE-miRNAs and DE-CKs. Overall, CTNNB1 mutation in HCC led to a decrease in chemokine expression and subsequent suppression of immune cell infiltration partly through regulating specific miRNA-IRG-CK axes, pointing to a potential combination of interference of Wnt/β-catenin signaling with immunotherapy in HCC with CTNNB1 mutation.
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Affiliation(s)
- Xuelian Xiao
- Department of Hepatobiliary Surgery, The First Affiliated Hospital of Xi'an Jiaotong University, 277 Yanta West Road, Xi'an, Shaanxi Province 710061, China
| | - Huanye Mo
- Department of Hepatobiliary Surgery, The First Affiliated Hospital of Xi'an Jiaotong University, 277 Yanta West Road, Xi'an, Shaanxi Province 710061, China
| | - Kangsheng Tu
- Department of Hepatobiliary Surgery, The First Affiliated Hospital of Xi'an Jiaotong University, 277 Yanta West Road, Xi'an, Shaanxi Province 710061, China.
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Takahashi M, Ikeda K, Ohmuraya M, Nakagawa Y, Sakuma T, Yamamoto T, Kawakami K. Six1 is required for signaling center formation and labial-lingual asymmetry in developing lower incisors. Dev Dyn 2020; 249:1098-1116. [PMID: 32243674 DOI: 10.1002/dvdy.174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 03/06/2020] [Accepted: 03/26/2020] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND The structure of the mouse incisor is characterized by its asymmetric accumulation of enamel matrix proteins on the labial side. The asymmetric structure originates from the patterning of the epithelial incisor placode through the interaction with dental mesenchymal cells. However, the molecular basis for the asymmetric patterning of the incisor germ is largely unknown. RESULTS A homeobox transcription factor SIX1 was shown to be produced in the mandibular mesenchyme, and its localization patterns changed dynamically during lower incisor development. Six1-/- mice exhibited smaller lower incisor primordia than wild-type mice. Furthermore, Six1-/- mice showed enamel matrix production on both the lingual and labial sides and disturbed odontoblast maturation. In the earlier stages of development, the formation of signaling centers, the initiation knot and the enamel knot, which are essential for the morphogenesis of tooth germs, were impaired in Six1-/- embryos. Notably, Wnt signaling activity, which shows an anterior-posterior gradient, and the expression patterns of genes involved in incisor formation were altered in the mesenchyme in Six1-/- embryos. CONCLUSION Our results indicate that Six1 is required for signaling center formation in lower incisor germs and the labial-lingual asymmetry of the lower incisors by regulating the anterior-posterior patterning of the mandibular mesenchyme.
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Affiliation(s)
- Masanori Takahashi
- Division of Biology, Center for Molecular Medicine, Jichi Medical University, Shimotsuke, Tochigi, Japan
| | - Keiko Ikeda
- Department of Physiology, International University of Health and Welfare, Narita, Chiba, Japan
| | - Masaki Ohmuraya
- Department of Genetics, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan
| | - Yoshiko Nakagawa
- Center for Animal Resources and Development, Kumamoto University, Kumamoto, Kumamoto, Japan
| | - Tetsushi Sakuma
- Division of Integrated Sciences for Life, Graduate School of Integrated Sciences for Life, Hiroshima University, HigashiHiroshima, Hiroshima, Japan
| | - Takashi Yamamoto
- Division of Integrated Sciences for Life, Graduate School of Integrated Sciences for Life, Hiroshima University, HigashiHiroshima, Hiroshima, Japan
| | - Kiyoshi Kawakami
- Division of Biology, Center for Molecular Medicine, Jichi Medical University, Shimotsuke, Tochigi, Japan
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7
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Novel strategies for expansion of tooth epithelial stem cells and ameloblast generation. Sci Rep 2020; 10:4963. [PMID: 32188889 PMCID: PMC7080756 DOI: 10.1038/s41598-020-60708-w] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 02/10/2020] [Indexed: 11/08/2022] Open
Abstract
Enamel is secreted by ameloblasts derived from tooth epithelial stem cells (SCs). Humans cannot repair or regenerate enamel, due to early loss of tooth epithelial SCs. Contrarily in the mouse incisors, epithelial SCs are maintained throughout life and endlessly generate ameloblasts, and thus enamel. Here we isolated Sox2-GFP+ tooth epithelial SCs which generated highly cellular spheres following a novel in vitro strategy. This system enabled analysis of SC regulation by various signaling molecules, and supported the stimulatory and inhibitory roles of Shh and Bmp, respectively; providing better insight into the heterogeneity of the SCs. Further, we generated a novel mouse reporter, Enamelin-tdTomato for identification of ameloblasts in live tissues and cells, and used it to demonstrate presence of ameloblasts in the new 3D co-culture system of dental SCs. Collectively, our results provide means of generating 3D tooth epithelium from adult SCs which can be utilized toward future generation of enamel.
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8
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Lu X, Yang J, Zhao S, Liu S. Advances of Wnt signalling pathway in dental development and potential clinical application. Organogenesis 2019; 15:101-110. [PMID: 31482738 DOI: 10.1080/15476278.2019.1656996] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Wnt signalling pathway is widely studied in many processes of biological development, like embryogenesis, tissue homeostasis and wound repair. It is universally known that Wnt signalling pathway plays an important role in tooth development. Here, we summarized the function of Wnt signalling pathway during tooth initiation, crown morphogenesis, root formation, and discussed the therapeutic potential of Wnt modulators.
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Affiliation(s)
- Xi Lu
- Department of Stomatology, Huashan Hospital, Fudan University , Shanghai , P. R. China
| | - Jun Yang
- Department of Stomatology, Huashan Hospital, Fudan University , Shanghai , P. R. China
| | - Shouliang Zhao
- Department of Stomatology, Huashan Hospital, Fudan University , Shanghai , P. R. China
| | - Shangfeng Liu
- Department of Stomatology, Huashan Hospital, Fudan University , Shanghai , P. R. China
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9
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Lu X, Chen X, Xing J, Lian M, Huang D, Lu Y, Feng G, Feng X. miR-140-5p regulates the odontoblastic differentiation of dental pulp stem cells via the Wnt1/β-catenin signaling pathway. Stem Cell Res Ther 2019; 10:226. [PMID: 31358066 PMCID: PMC6664499 DOI: 10.1186/s13287-019-1344-4] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Revised: 07/03/2019] [Accepted: 07/15/2019] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND MicroRNAs (miRNAs) play a key role in regulating cell differentiation. In the present study, we aimed to explore the role of miR-140-5p in odontoblastic differentiation of dental pulp stem cells (DPSCs). METHODS DPSCs from normal human impacted third molars were isolated and cultured. After overexpression or silencing of miR-140-5p in DPSCs, activity, proliferation, and odontoblastic differentiation of DPSCs were evaluated. The possible target gene of miR-140-5p was verified by luciferase reporter gene assay. Using gene transfection technology, RT-CPR, and Western blot to confirm miR-140-5p regulates the odontoblastic differentiation of DPSCs through Wnt1/β-catenin signaling. RESULTS We found the expression of miR-140-5p decreased in the differentiated DPSCs for odontoblastic cells, and at the same time, the expressions of Wnt1 and β-catenin increased. Wnt1 was the target gene of miR-140-5p which was confirmed by luciferase reporter gene system. miR-140-5p overexpression suppressed the expression of Wnt1. miR-140-5p inhibitor could promote the odontoblastic differentiation of DPSCs. miR-140-5p mimic could weaken the odontoblastic differentiation of DPSCs, which could be reversed by the overexpression of Wnt1. CONCLUSION Our data demonstrated that miR-140-5p regulates the odontoblastic differentiation of DPSCs via targeting Wnt1/β-catenin signaling. Therefore, miR-140-5p might be a molecular target to regulate the odontoblastic differentiation for the therapeutic agents in dental medicine.
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Affiliation(s)
- Xiaohui Lu
- Department of Stomatology, Affiliated Hospital of Nantong University, 20 Xisi Road, Nantong, 226001, Jiangsu, China
| | - Xi Chen
- Department of Stomatology, Stomatological Hospital of Zhenjiang, Zhenjiang, Jiangsu, China
| | - Jing Xing
- Department of Stomatology, Affiliated Hospital of Nantong University, 20 Xisi Road, Nantong, 226001, Jiangsu, China
| | - Min Lian
- Department of Stomatology, Affiliated Hospital of Nantong University, 20 Xisi Road, Nantong, 226001, Jiangsu, China
| | - Dan Huang
- Department of Stomatology, Affiliated Hospital of Nantong University, 20 Xisi Road, Nantong, 226001, Jiangsu, China
| | - Yuanzhou Lu
- Department of Cardiology, The People's Hospital of Tongzhou, Nantong, Jiangsu, China
| | - Guijuan Feng
- Department of Stomatology, Affiliated Hospital of Nantong University, 20 Xisi Road, Nantong, 226001, Jiangsu, China.
| | - Xingmei Feng
- Department of Stomatology, Affiliated Hospital of Nantong University, 20 Xisi Road, Nantong, 226001, Jiangsu, China.
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10
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Binder M, Chmielarz P, Mckinnon PJ, Biggs LC, Thesleff I, Balic A. Functionally Distinctive Ptch Receptors Establish Multimodal Hedgehog Signaling in the Tooth Epithelial Stem Cell Niche. Stem Cells 2019; 37:1238-1248. [PMID: 31145830 DOI: 10.1002/stem.3042] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 04/29/2019] [Accepted: 05/14/2019] [Indexed: 01/06/2023]
Abstract
Continuous growth of the mouse incisor teeth is due to the life-long maintenance of epithelial stem cells (SCs) in their niche called cervical loop (CL). Several signaling factors regulate SC maintenance and/or their differentiation to achieve organ homeostasis. Previous studies indicated that Hedgehog signaling is crucial for both the maintenance of the SCs in the niche, as well as for their differentiation. How Hedgehog signaling regulates these two opposing cellular behaviors within the confinement of the CL remains elusive. In this study, we used in vitro organ and cell cultures to pharmacologically attenuate Hedgehog signaling. We analyzed expression of various genes expressed in the SC niche to determine the effect of altered Hedgehog signaling on the cellular hierarchy within the niche. These genes include markers of SCs (Sox2 and Lgr5) and transit-amplifying cells (P-cadherin, Sonic Hedgehog, and Yap). Our results show that Hedgehog signaling is a critical survival factor for SCs in the niche, and that the architecture and the diversity of the SC niche are regulated by multiple Hedgehog ligands. We demonstrated the presence of an additional Hedgehog ligand, nerve-derived Desert Hedgehog, secreted in the proximity of the CL. In addition, we provide evidence that Hedgehog receptors Ptch1 and Ptch2 elicit independent responses, which enable multimodal Hedgehog signaling to simultaneously regulate SC maintenance and differentiation. Our study indicates that the cellular hierarchy in the continuously growing incisor is a result of complex interplay of two Hedgehog ligands with functionally distinct Ptch receptors. Stem Cells 2019;37:1238-1248.
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Affiliation(s)
- Martin Binder
- Research Program in Developmental Biology, Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Piotr Chmielarz
- Research Program in Developmental Biology, Institute of Biotechnology, University of Helsinki, Helsinki, Finland.,Department of Brain Biochemistry, Institute of Pharmacology, Polish Academy of Sciences, Krakow, Poland
| | - Peter J Mckinnon
- Department of Genetics, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Leah C Biggs
- Research Program in Developmental Biology, Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Irma Thesleff
- Research Program in Developmental Biology, Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Anamaria Balic
- Research Program in Developmental Biology, Institute of Biotechnology, University of Helsinki, Helsinki, Finland
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11
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Shi C, Yuan Y, Guo Y, Jing J, Ho TV, Han X, Li J, Feng J, Chai Y. BMP Signaling in Regulating Mesenchymal Stem Cells in Incisor Homeostasis. J Dent Res 2019; 98:904-911. [PMID: 31136721 DOI: 10.1177/0022034519850812] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Bone morphogenetic protein (BMP) signaling performs multiple essential functions during craniofacial development. In this study, we used the adult mouse incisor as a model to uncover how BMP signaling maintains tissue homeostasis and regulates mesenchymal stem cell (MSC) fate by mediating WNT and FGF signaling. We observed a severe defect in the proximal region of the adult mouse incisor after loss of BMP signaling in the Gli1+ cell lineage, indicating that BMP signaling is required for cell proliferation and odontoblast differentiation. Our study demonstrates that BMP signaling serves as a key regulator that antagonizes WNT and FGF signaling to regulate MSC lineage commitment. In addition, BMP signaling in the Gli1+ cell lineage is also required for the maintenance of quiescent MSCs, suggesting that BMP signaling not only is important for odontoblast differentiation but also plays a crucial role in providing feedback to the MSC population. This study highlights multiple important roles of BMP signaling in regulating tissue homeostasis.
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Affiliation(s)
- C Shi
- 1 Center for Craniofacial Molecular Biology, University of Southern California, Los Angeles, CA, USA.,2 Department of Orthodontics, The Affiliated Stomatology Hospital of Kunming Medical University, Kunming, China
| | - Y Yuan
- 1 Center for Craniofacial Molecular Biology, University of Southern California, Los Angeles, CA, USA
| | - Y Guo
- 1 Center for Craniofacial Molecular Biology, University of Southern California, Los Angeles, CA, USA.,3 Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology, Beijing, China
| | - J Jing
- 1 Center for Craniofacial Molecular Biology, University of Southern California, Los Angeles, CA, USA.,4 State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - T V Ho
- 1 Center for Craniofacial Molecular Biology, University of Southern California, Los Angeles, CA, USA
| | - X Han
- 1 Center for Craniofacial Molecular Biology, University of Southern California, Los Angeles, CA, USA
| | - J Li
- 1 Center for Craniofacial Molecular Biology, University of Southern California, Los Angeles, CA, USA.,5 Molecular Laboratory for Gene Therapy and Tooth Regeneration, Beijing Key Laboratory of Tooth Regeneration and Function Reconstruction, Capital Medical University School of Stomatology, Beijing, China
| | - J Feng
- 1 Center for Craniofacial Molecular Biology, University of Southern California, Los Angeles, CA, USA
| | - Y Chai
- 1 Center for Craniofacial Molecular Biology, University of Southern California, Los Angeles, CA, USA
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12
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Zhang S, Choi HS, Jung HS, Lee JM. FGF10 Is Required for Circumvallate Papilla Morphogenesis by Maintaining Lgr5 Activity. Front Physiol 2018; 9:1192. [PMID: 30233392 PMCID: PMC6127645 DOI: 10.3389/fphys.2018.01192] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Accepted: 08/07/2018] [Indexed: 11/17/2022] Open
Abstract
Taste buds develop in different regions of the mammal oral cavity. Adult stem cells in various organs including the tongue papillae are marked by leucine-rich repeat-containing G protein-coupled receptor 5 (Lgr5) and its homolog, Lgr6. Recent studies have reported that adult taste stem/progenitor cells in circumvallate papilla (CVP) on the posterior tongue are Lgr5-positive. In this study, we confirm the Lgr5 expression pattern during CVP development. A previous study reported that mesenchymal Fgf10 is necessary for maintaining epithelial Lgr5-positive stem/progenitor cells. To confirm the interaction between Lgr5-positive CVP epithelium and mesenchymal factor FGF10, reverse recombination (180-degree) was performed after tongue epithelium detachment. FGF10 protein-soaked bead implantation was performed after reverse recombination to rescue CVP development. Moreover, we reduced mesenchymal Fgf10 by BIO and SU5402 treatment which disrupted CVP morphogenesis. This study suggests that the crosstalk between epithelial Lgr5 and mesenchymal Fgf10 plays a pivotal role in CVP epithelium invagination during mouse tongue CVP development by maintaining Lgr5-positive stem/progenitor cells.
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Affiliation(s)
- Sushan Zhang
- Division in Anatomy and Developmental Biology, Department of Oral Biology, Oral Science Research Center, BK21 PLUS Project, Yonsei University College of Dentistry, Seoul, South Korea
| | - Hyuk Su Choi
- Division in Anatomy and Developmental Biology, Department of Oral Biology, Oral Science Research Center, BK21 PLUS Project, Yonsei University College of Dentistry, Seoul, South Korea
| | - Han-Sung Jung
- Division in Anatomy and Developmental Biology, Department of Oral Biology, Oral Science Research Center, BK21 PLUS Project, Yonsei University College of Dentistry, Seoul, South Korea.,Applied Oral Sciences, Faculty of Dentistry, The University of Hong Kong, Hong Kong, Hong Kong
| | - Jong-Min Lee
- Division in Anatomy and Developmental Biology, Department of Oral Biology, Oral Science Research Center, BK21 PLUS Project, Yonsei University College of Dentistry, Seoul, South Korea
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13
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Altered Notch Signaling in Developing Molar Teeth of Pituitary Adenylate Cyclase-Activating Polypeptide (PACAP)-Deficient Mice. J Mol Neurosci 2018; 68:377-388. [PMID: 30094580 DOI: 10.1007/s12031-018-1146-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Accepted: 07/27/2018] [Indexed: 10/28/2022]
Abstract
Pituitary adenylate cyclase-activating polypeptide (PACAP) is a neuropeptide with neuroprotective and neurotrophic effects. This suggests its influence on the development of teeth, which are, similarly to the nervous system, ectoderm and neural crest derivatives. Our earlier studies have shown morphological differences between wild-type (WT) and PACAP-deficient mice, with upregulated sonic hedgehog (SHH) signaling in the lack of PACAP. Notch signaling is a key element of proper tooth development by regulating apoptosis and cell proliferation. In this study, our main goal was to evaluate the possible effects of PACAP on Notch signaling pathway. Immunohistochemical staining was performed of Notch receptors (Notch1, 2, 3, 4), their ligands [delta-like protein (DLL)1, 3, 4, Jagged1, 2], and intracellular target molecules [CSL (CBF1 humans/Su (H) Drosophila/LAG1 Caenorhabditis elegans transcription factor); TACE (TNF-α converting enzyme), NUMB] in molar teeth of 5-day-old WT, and homozygous and heterozygous PACAP-deficient mice. We measured immunopositivity in the enamel-producing ameloblasts and dentin-producing odontoblasts. Notch2 receptor and DLL1 expression were elevated in ameloblasts of PACAP-deficient mice compared to those in WT ones. The expression of CSL showed similar results both in the ameloblasts and odontoblasts. Jagged1 ligand expression was elevated in the odontoblasts of homozygous PACAP-deficient mice compared to WT mice. Other Notch pathway elements did not show significant differences between the genotype groups. The lack of PACAP leads to upregulation of Notch pathway elements in the odontoblast and ameloblast cells. The underlying molecular mechanisms are yet to be elucidated; however, we propose SHH-dependent and independent processes. We hypothesize that this compensatory upregulation of Notch signaling by the lack of PACAP could represent a salvage pathway in PACAP-deficient animals.
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14
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Runx1-Stat3 signaling regulates the epithelial stem cells in continuously growing incisors. Sci Rep 2018; 8:10906. [PMID: 30026553 PMCID: PMC6053438 DOI: 10.1038/s41598-018-29317-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Accepted: 07/09/2018] [Indexed: 11/08/2022] Open
Abstract
Rodent incisors grow permanently and the homeostasis of enamel production is maintained by a continuous supply of epithelial progenitors from putative stem cells in the cervical loop. We herein report that Runx1 regulates the Lgr5-expressing epithelial stem cells and their subsequent continuous differentiation into ameloblasts. Mice deficient in epithelial Runx1 demonstrate remarkable shortening of the incisors with underdevelopment of the cervical loop and enamel defects. In this mutant cervical loop, the proliferation of the dental epithelium was significantly disturbed and the expression of Lgr5 and enamel matrix proteins was remarkably downregulated. Interestingly, the expression of Socs3, an inhibitor of Stat3 signaling, was upregulated and Stat3 phosphorylation was suppressed specifically in the mutant cervical loop. The expression of Lgr5 and the enamel matrix protein in the wild-type incisor germs is disturbed by pharmaceutical Stat3 inhibition in vitro., of. Conversely, pharmaceutical activation of Stat3 rescues the defective phenotypes of the Runx1 mutant with upregulated Lgr5 and enamel matrix protein genes. The present results provide the first evidence of the role of Runx1 regulates the Lgr5-expressing epithelial stem cells and differentiation of ameloblast progenitors in the developing incisors. Our study also demonstrates that Stat3 modulates the Runx1-Lgr5 axis in the cervical loop.
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15
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An Z, Akily B, Sabalic M, Zong G, Chai Y, Sharpe PT. Regulation of Mesenchymal Stem to Transit-Amplifying Cell Transition in the Continuously Growing Mouse Incisor. Cell Rep 2018; 23:3102-3111. [PMID: 29874594 PMCID: PMC6383149 DOI: 10.1016/j.celrep.2018.05.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Revised: 02/22/2018] [Accepted: 04/25/2018] [Indexed: 12/25/2022] Open
Abstract
In adult tissues and organs with high turnover rates, the generation of transit-amplifying cell (TAC) populations from self-renewing stem cells drives cell replacement. The role of stem cells is to provide a renewable source of cells that give rise to TACs to provide the cell numbers that are necessary for cell differentiation. Regulation of the formation of TACs is thus fundamental to controlling cell replacement. Here, we analyze the properties of a population of mesenchymal TACs in the continuously growing mouse incisor to identify key components of the molecular regulation that drives proliferation. We show that the polycomb repressive complex 1 acts as a global regulator of the TAC phenotype by its direct action on the expression of key cell-cycle regulatory genes and by regulating Wnt/β-catenin-signaling activity. We also identify an essential requirement for TACs in maintaining mesenchymal stem cells, which is indicative of a positive feedback mechanism.
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Affiliation(s)
- Zhengwen An
- Centre for Craniofacial and Regenerative Biology, Dental Institute, Kings College, London, UK
| | - Basem Akily
- Centre for Craniofacial and Regenerative Biology, Dental Institute, Kings College, London, UK
| | - Maja Sabalic
- Centre for Craniofacial and Regenerative Biology, Dental Institute, Kings College, London, UK
| | - Guo Zong
- Centre for Craniofacial and Regenerative Biology, Dental Institute, Kings College, London, UK
| | - Yang Chai
- Center for Craniofacial Molecular Biology, University of Southern California, Los Angeles, CA, USA
| | - Paul T Sharpe
- Centre for Craniofacial and Regenerative Biology, Dental Institute, Kings College, London, UK.
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16
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Guo Y, Guo W, Chen J, Tian Y, Chen G, Tian W, Bai D. Comparative study on differentiation of cervical-loop cells and Hertwig's epithelial root sheath cells under the induction of dental follicle cells in rat. Sci Rep 2018; 8:6546. [PMID: 29695816 PMCID: PMC5916884 DOI: 10.1038/s41598-018-24973-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Accepted: 04/12/2018] [Indexed: 02/05/2023] Open
Abstract
Cervical loop cells (CLC) and Hertwig's epithelial root sheath (HERS) cells are believed to play critical roles in distinct developmental patterns between rodent incisors and molars, respectively. However, the differences in differentiation between CLC and HERS cells, and their response to inductions from dental follicle cells, remain largely unknown. In present study, CLC and HERS cells, as well as incisor dental follicle (IF) cells and molar dental follicle (MF) cells were isolated from post-natal 7-day rats. IF and MF cell derived conditioned medium (CM) was obtained for induction of CLC and HERS cells. In vitro experiments, we found that, under the induction of dental follicle cell derived CM, CLC cells maintained the epithelial polygonal-shapes and formed massive minerals, while part of HERS cells underwent shape transformation and generated granular minerals. CLC cells expressed higher enamel-forming and mineralization related genes, while HERS cells showed opposite expression patterns of BMP2, BMP4, AMBN and AMGN. In vivo, CLC cells generated enamel-like tissues while HERS cells formed cementum-periodontal ligament-like structures. Taken together, CLC and HERS cells present distinct differentiation patterns under the inductions from dental follicle cells.
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Affiliation(s)
- Yongwen Guo
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, P.R. China.,National Engineering Laboratory for Oral Regenerative Medicine, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, P.R. China.,Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, P.R. China
| | - Weihua Guo
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, P.R. China.,National Engineering Laboratory for Oral Regenerative Medicine, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, P.R. China.,Department of Pediatric Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, P.R. China
| | - Jie Chen
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, P.R. China.,National Engineering Laboratory for Oral Regenerative Medicine, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, P.R. China.,Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, P.R. China
| | - Ye Tian
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, P.R. China.,National Engineering Laboratory for Oral Regenerative Medicine, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, P.R. China.,Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, P.R. China
| | - Guoqing Chen
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, P.R. China.,National Engineering Laboratory for Oral Regenerative Medicine, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, P.R. China
| | - Weidong Tian
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, P.R. China. .,National Engineering Laboratory for Oral Regenerative Medicine, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, P.R. China. .,Department of Oral and Maxillofacial Surgery, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, P.R. China.
| | - Ding Bai
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, P.R. China. .,Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, P.R. China.
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17
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Shin HS, Lee S, Kim YM, Lim JY. Hypoxia-Activated Adipose Mesenchymal Stem Cells Prevents Irradiation-Induced Salivary Hypofunction by Enhanced Paracrine Effect Through Fibroblast Growth Factor 10. Stem Cells 2018; 36:1020-1032. [PMID: 29569790 DOI: 10.1002/stem.2818] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Revised: 02/12/2018] [Accepted: 02/17/2018] [Indexed: 12/13/2022]
Abstract
To explore the effects and mechanisms of paracrine factors secreted from human adipose mesenchymal stem cell (hAdMSCs) that are activated by hypoxia on radioprotection against irradiation-induced salivary hypofunction in subjects undergoing radiotherapy for head and neck cancers. An organotypic spheroid coculture model to mimic irradiation (IR)-induced salivary hypofunction was set up for in vitro experiments. Human parotid gland epithelial cells were organized to form three-dimensional (3D) acinus-like spheroids on growth factor reduced -Matrigel. Cellular, structural, and functional damage following IR were examined after cells were cocultured with hAdMSCs preconditioned with either normoxia (hAdMSCNMX ) or hypoxia (hAdMSCHPX ). A key paracrine factor secreted by hAdMSCsHPX was identified by high-throughput microarray-based enzyme-linked immunosorbent assay. Molecular mechanisms and signaling pathways on radioprotection were explored. Therapeutic effects of hAdMSCsHPX were evaluated after in vivo transplant into mice with IR-induced salivary hypofunction. In our 3D coculture experiment, hAdMSCsHPX significantly enhanced radioresistance of spheroidal human parotid epithelial cells, and led to greater preservation of salivary epithelial integrity and acinar secretory function relative to hAdMSCsNMX . Coculture with hAdMSCsHPX promoted FGFR expression and suppressed FGFR diminished antiapoptotic activity of hAdMSCsHPX . Among FGFR-binding secreted factors, we found that fibroblast growth factor 10 (FGF10) contributed to therapeutic effects of hAdMSCsHPX by enhancing antiapoptotic effect, which was dependent on FGFR-PI3K signaling. An in vivo transplant of hAdMSCsHPX into irradiated salivary glands of mice reversed IR-induced salivary hypofunction where hAdMSC-released FGF10 contributed to tissue remodeling. Our results suggest that hAdMSCsHPX protect salivary glands from IR-induced apoptosis and preserve acinar structure and functions by activation of FGFR-PI3K signaling via actions of hAdMSC-secreted factors, including FGF10. Stem Cells 2018;36:1020-1032.
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Affiliation(s)
- Hyun-Soo Shin
- Department of Otorhinolaryngology, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Songyi Lee
- Department of Otorhinolaryngology, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Young-Mo Kim
- Department of Otorhinolaryngology, Inha University College of Medicine, Incheon, Republic of Korea
| | - Jae-Yol Lim
- Department of Otorhinolaryngology, Yonsei University College of Medicine, Seoul, Republic of Korea
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18
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Sanz-Navarro M, Seidel K, Sun Z, Bertonnier-Brouty L, Amendt BA, Klein OD, Michon F. Plasticity within the niche ensures the maintenance of a Sox2+ stem cell population in the mouse incisor. Development 2018; 145:dev.155929. [PMID: 29180573 DOI: 10.1242/dev.155929] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2017] [Accepted: 11/15/2017] [Indexed: 12/16/2022]
Abstract
In mice, the incisors grow throughout the animal's life, and this continuous renewal is driven by dental epithelial and mesenchymal stem cells. Sox2 is a principal marker of the epithelial stem cells that reside in the mouse incisor stem cell niche, called the labial cervical loop, but relatively little is known about the role of the Sox2+ stem cell population. In this study, we show that conditional deletion of Sox2 in the embryonic incisor epithelium leads to growth defects and impairment of ameloblast lineage commitment. Deletion of Sox2 specifically in Sox2+ cells during incisor renewal revealed cellular plasticity that leads to the relatively rapid restoration of a Sox2-expressing cell population. Furthermore, we show that Lgr5-expressing cells are a subpopulation of dental Sox2+ cells that also arise from Sox2+ cells during tooth formation. Finally, we show that the embryonic and adult Sox2+ populations are regulated by distinct signalling pathways, which is reflected in their distinct transcriptomic signatures. Together, our findings demonstrate that a Sox2+ stem cell population can be regenerated from Sox2- cells, reinforcing its importance for incisor homeostasis.
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Affiliation(s)
- Maria Sanz-Navarro
- Helsinki Institute of Life Sciences, Institute of Biotechnology, University of Helsinki, 00014 Helsinki, Finland.,Orthodontics, Department of Oral and Maxillofacial Diseases, University of Helsinki, 00290 Helsinki, Finland
| | - Kerstin Seidel
- Department of Orofacial Sciences and Program in Craniofacial Biology, UCSF, San Francisco, CA 94143, USA
| | - Zhao Sun
- Department of Anatomy and Cell Biology, and the Craniofacial Anomalies Research Center, The University of Iowa, Iowa City, IA 52242, USA
| | - Ludivine Bertonnier-Brouty
- Helsinki Institute of Life Sciences, Institute of Biotechnology, University of Helsinki, 00014 Helsinki, Finland.,Département de Biologie, École Normale Supérieure de Lyon, Université de Lyon, 69007 Lyon, France
| | - Brad A Amendt
- Department of Anatomy and Cell Biology, and the Craniofacial Anomalies Research Center, The University of Iowa, Iowa City, IA 52242, USA.,College of Dentistry, The University of Iowa, Iowa City, IA 52242, USA
| | - Ophir D Klein
- Department of Orofacial Sciences and Program in Craniofacial Biology, UCSF, San Francisco, CA 94143, USA.,Department of Pediatrics and Institute for Human Genetics, University of California San Francisco, San Francisco, CA 94143, USA
| | - Frederic Michon
- Helsinki Institute of Life Sciences, Institute of Biotechnology, University of Helsinki, 00014 Helsinki, Finland .,Keele Medical School and Institute for Science and Technology in Medicine, Keele University, Keele ST5 5BG, UK
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19
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Cantù C, Pagella P, Shajiei TD, Zimmerli D, Valenta T, Hausmann G, Basler K, Mitsiadis TA. A cytoplasmic role of Wnt/β-catenin transcriptional cofactors Bcl9, Bcl9l, and Pygopus in tooth enamel formation. Sci Signal 2017; 10:10/465/eaah4598. [PMID: 28174279 DOI: 10.1126/scisignal.aah4598] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Wnt-stimulated β-catenin transcriptional regulation is necessary for the development of most organs, including teeth. Bcl9 and Bcl9l are tissue-specific transcriptional cofactors that cooperate with β-catenin. In the nucleus, Bcl9 and Bcl9l simultaneously bind β-catenin and the transcriptional activator Pygo2 to promote the transcription of a subset of Wnt target genes. We showed that Bcl9 and Bcl9l function in the cytoplasm during tooth enamel formation in a manner that is independent of Wnt-stimulated β-catenin-dependent transcription. Bcl9, Bcl9l, and Pygo2 localized mainly to the cytoplasm of the epithelial-derived ameloblasts, the cells responsible for enamel production. In ameloblasts, Bcl9 interacted with proteins involved in enamel formation and proteins involved in exocytosis and vesicular trafficking. Conditional deletion of both Bcl9 and Bcl9l or both Pygo1 and Pygo2 in mice produced teeth with defective enamel that was bright white and deficient in iron, which is reminiscent of human tooth enamel pathologies. Overall, our data revealed that these proteins, originally defined through their function as β-catenin transcriptional cofactors, function in odontogenesis through a previously uncharacterized cytoplasmic mechanism, revealing that they have roles beyond that of transcriptional cofactors.
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Affiliation(s)
- Claudio Cantù
- Institute of Molecular Life Sciences, University of Zurich, 8057 Zurich, Switzerland
| | - Pierfrancesco Pagella
- Orofacial Development and Regeneration, Institute of Oral Biology, Center of Dental Medicine, University of Zurich, 8032 Zurich, Switzerland
| | - Tania D Shajiei
- Orofacial Development and Regeneration, Institute of Oral Biology, Center of Dental Medicine, University of Zurich, 8032 Zurich, Switzerland
| | - Dario Zimmerli
- Institute of Molecular Life Sciences, University of Zurich, 8057 Zurich, Switzerland
| | - Tomas Valenta
- Institute of Molecular Life Sciences, University of Zurich, 8057 Zurich, Switzerland
| | - George Hausmann
- Institute of Molecular Life Sciences, University of Zurich, 8057 Zurich, Switzerland
| | - Konrad Basler
- Institute of Molecular Life Sciences, University of Zurich, 8057 Zurich, Switzerland.
| | - Thimios A Mitsiadis
- Orofacial Development and Regeneration, Institute of Oral Biology, Center of Dental Medicine, University of Zurich, 8032 Zurich, Switzerland.
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20
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Tsai S, Abdelhamid A, Khan MK, Elkarargy A, Widelitz RB, Chuong CM, Wu P. The Molecular Circuit Regulating Tooth Development in Crocodilians. J Dent Res 2016; 95:1501-1510. [PMID: 27872325 DOI: 10.1177/0022034516667724] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Alligators have robust regenerative potential for tooth renewal. In contrast, extant mammals can either renew their teeth once (diphyodont dentition, as found in humans) or not at all (monophyodont dentition, present in mice). Previously, the authors used multiple mitotic labeling to map putative stem cells in alligator dental laminae, which contain quiescent odontogenic progenitors. The authors demonstrated that alligator tooth cycle initiation is related to β-catenin/Wnt pathway activity in the dental lamina bulge. However, the molecular circuitry underlying the developmental progression of polyphyodont teeth remains elusive. Here, the authors used transcriptomic analyses to examine the additional molecular pathways related to the process of alligator tooth development. The authors collected juvenile alligator dental laminae at different developmental stages and performed RNA-seq. This data shows that Wnt, bone morphogenetic protein (BMP), and fibroblast growth factor (FGF) pathways are activated at the transition from pre-initiation stage (bud) to initiation stage (cap). Intriguingly, the activation of Wnt ligands, receptors and co-activators accompanies the inactivation of Wnt antagonists. In addition, the authors identified the molecular circuitry at different stages of tooth development. The authors conclude that multiple pathways are associated with specific stages of tooth development in the alligator. This data shows that Wnt pathway activation may play the most important role in the initiation of tooth development. This result may offer insight into ways to modulate the genetic controls involved in mammalian tooth renewal.
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Affiliation(s)
- S Tsai
- Department of Pathology, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA.,Ostrow School of Dentistry, University of Southern California, Los Angeles, CA, USA.,Graduate School of Clinical Dentistry, National Taiwan University, Taipei, Taiwan.,Research Center for Developmental Biology and Regenerative Medicine, National Taiwan University, Taipei, Taiwan
| | - A Abdelhamid
- Qassim College of Dentistry, Qassim University, Saudi Arabia
| | - M K Khan
- Qassim College of Dentistry, Qassim University, Saudi Arabia
| | - A Elkarargy
- Qassim College of Dentistry, Qassim University, Saudi Arabia
| | - R B Widelitz
- Department of Pathology, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - C M Chuong
- Department of Pathology, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA.,Research Center for Developmental Biology and Regenerative Medicine, National Taiwan University, Taipei, Taiwan.,Integrative Stem Cell Center, China Medical University Hospital, China Medical University, Taichung, Taiwan
| | - P Wu
- Department of Pathology, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
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21
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Xi J, He S, Wei C, Shen W, Liu J, Li K, Zhang Y, Yue J, Yang Z. Negative effects of retinoic acid on stem cell niche of mouse incisor. Stem Cell Res 2016; 17:489-497. [PMID: 27771497 DOI: 10.1016/j.scr.2016.09.030] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Revised: 09/27/2016] [Accepted: 09/27/2016] [Indexed: 01/01/2023] Open
Abstract
The continuous growth of mouse incisors depends on epithelial stem cells (SCs) residing in the SC niche, called labial cervical loop (LaCL). The homeostasis of the SCs is subtly regulated by complex signaling networks. In this study, we focus on retinoic acid (RA), a derivative of Vitamin A and a known pivotal signaling molecule in controlling the functions of stem cells (SCs). We analyzed the expression profiles of several key molecules of the RA signaling pathway in cultured incisor explants upon exogenous RA treatment. The expression patterns of these molecules suggested a negative feedback regulation of RA signaling in the developing incisor. We demonstrated that exogenous RA had negative effects on incisor SCs and that this was accompanied by downregulation of Fgf10, a mesenchymally expressed SC survival factor in the mouse incisor. Supplement of Fgf10 in incisor cultures completely blocked RA effects by antagonizing apoptosis and increasing proliferation in LaCL epithelial SCs. In addition, Fgf10 obviously antagonized RA-induced downregulation of the SC marker Sox2 in incisor epithelial SCs. Our findings suggest that the negative effects of RA on incisor SCs result from inhibition of mesenchymal Fgf10.
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Affiliation(s)
- Jinlei Xi
- Department of Pharmacy, Wuhan University of Science and Technology School of Medicine, 2 West Huangjiahu Road, Wuhan, Hubei 430065, China
| | - Shijing He
- Department of Pharmacology, Wuhan University School of Basic Medical Science, 185 Donghu Road, Wuhan, Hubei 430071, China
| | - Cizhao Wei
- Department of Pharmacology, Wuhan University School of Basic Medical Science, 185 Donghu Road, Wuhan, Hubei 430071, China
| | - Wanyao Shen
- Department of Pharmacology, Wuhan University School of Basic Medical Science, 185 Donghu Road, Wuhan, Hubei 430071, China
| | - Juan Liu
- Department of Pharmacy, Wuhan University of Science and Technology School of Medicine, 2 West Huangjiahu Road, Wuhan, Hubei 430065, China
| | - Ke Li
- Department of Pharmacology, Wuhan University School of Basic Medical Science, 185 Donghu Road, Wuhan, Hubei 430071, China
| | - Yufeng Zhang
- The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) & Key Laboratory of Oral Biomedicine Ministry of Education, School & Hospital of Stomatology, Wuhan University, Wuhan 430079, China
| | - Jiang Yue
- Department of Pharmacology, Wuhan University School of Basic Medical Science, 185 Donghu Road, Wuhan, Hubei 430071, China
| | - Zheqiong Yang
- Department of Pharmacology, Wuhan University School of Basic Medical Science, 185 Donghu Road, Wuhan, Hubei 430071, China.
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22
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LGR4 is required for sequential molar development. Biochem Biophys Rep 2016; 8:174-183. [PMID: 28955954 PMCID: PMC5613770 DOI: 10.1016/j.bbrep.2016.08.018] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Revised: 07/30/2016] [Accepted: 08/14/2016] [Indexed: 12/20/2022] Open
Abstract
Tooth development requires proliferation, differentiation, and specific migration of dental epithelial cells, through well-organized signaling interactions with mesenchymal cells. Recently, it has been reported that leucine-rich repeat-containing G protein coupled receptor 4 (LGR4), the receptor of R-spondins, is expressed in many epithelial cells in various organs and tissues and is essential for organ development and stem cell maintenance. Here, we report that LGR4 contributes to the sequential development of molars in mice. LGR4 expression in dental epithelium was detected in SOX2+ cells in the posterior end of the second molar (M2) and the early tooth germ of the third molar (M3). In keratinocyte-specific Lgr4-deficient mice (Lgr4K5 KO), the developmental defect became obvious by postnatal day 14 (P14) in M3. Lgr4K5 KO adult mice showed complete absence or the dwarfed form of M3. In M3 development in Lgr4K5 KO mice, at Wnt/β-catenin signal activity was down-regulated in the dental epithelium at P3, as indicated by lymphoid enhancer-binding factor-1 (LEF1) expression. We also confirmed the decrease, in dental epithelium of Lgr4K5 KO mice, of the number of SOX2+ cells and the arrest of cell proliferation at P7, and observed abnormal differentiation at P14. Our data demonstrated that LGR4 controls the sequential development of molars by maintaining SOX2+ cells in the dental epithelium, which have the ability to form normal molars. LGR4 expression was observed in the dental epithelium after birth and moved posteriorly during molar development. Keratin5-Cre Tg specific deletion of Lgr4 impaired the development of the third molar. LGR4 maintained SOX2 positive and proliferative cells in the dental epithelium of molars.
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23
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Wnt Signaling in Renal Cell Carcinoma. Cancers (Basel) 2016; 8:cancers8060057. [PMID: 27322325 PMCID: PMC4931622 DOI: 10.3390/cancers8060057] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Revised: 05/31/2016] [Accepted: 06/12/2016] [Indexed: 01/09/2023] Open
Abstract
Renal cell carcinoma (RCC) accounts for 90% of all kidney cancers. Due to poor diagnosis, high resistance to the systemic therapies and the fact that most RCC cases occur sporadically, current research switched its focus on studying the molecular mechanisms underlying RCC. The aim is the discovery of new effective and less toxic anti-cancer drugs and novel diagnostic markers. Besides the PI3K/Akt/mTOR, HGF/Met and VHL/hypoxia cellular signaling pathways, the involvement of the Wnt/β-catenin pathway in RCC is commonly studied. Wnt signaling and its targeted genes are known to actively participate in different biological processes during embryonic development and renal cancer. Recently, studies have shown that targeting this pathway by alternating/inhibiting its intracellular signal transduction can reduce cancer cells viability and inhibit their growth. The targets and drugs identified show promising potential to serve as novel RCC therapeutics and prognostic markers. This review aims to summarize the current status quo regarding recent research on RCC focusing on the involvement of the Wnt/β-catenin pathway and how its understanding could facilitate the identification of potential therapeutic targets, new drugs and diagnostic biomarkers.
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24
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Structural and Morphometric Comparison of Lower Incisors in PACAP-Deficient and Wild-Type Mice. J Mol Neurosci 2016; 59:300-8. [PMID: 27154515 DOI: 10.1007/s12031-016-0765-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Accepted: 04/27/2016] [Indexed: 10/21/2022]
Abstract
Pituitary adenylate cyclase activating polypeptide (PACAP) is a neuropeptide with widespread distribution. PACAP plays an important role in the development of the nervous system, it has a trophic and protective effect, and it is also implicated in the regulation of various physiological functions. Teeth are originated from the mesenchyme of the neural crest and the ectoderm of the first branchial arch, suggesting similarities with the development of the nervous system. Earlier PACAP-immunoreactive fibers have been found in the odontoblastic and subodontoblastic layers of the dental pulp. Our previous examinations have shown that PACAP deficiency causes alterations in the morphology and structure of the developing molars of 7-day-old mice. In our present study, morphometric and structural comparison was performed on the incisors of 1-year-old wild-type and PACAP-deficient mice. Hard tissue density measurements and morphometric comparison were carried out on the mandibles and the lower incisors with micro-CT. For structural examination, Raman microscopy was applied on frontal thin sections of the mandible. With micro-CT morphometrical measurements, the size of the incisors and the relative volume of the pulp to dentin were significantly smaller in the PACAP-deficient group compared to the wild-type animals. The density of calcium hydroxyapatite in the dentin was reduced in the PACAP-deficient mice. No structural differences could be observed in the enamel with Raman microscopy. Significant differences were found in the dentin of PACAP-deficient mice with Raman microscopy, where increased carbonate/phosphate ratio indicates higher intracrystalline disordering. The evaluation of amide III bands in the dentin revealed higher structural diversity in wild-type mice. Based upon our present and previous results, it is obvious that PACAP plays an important role in tooth development with the regulation of morphogenesis, dentin, and enamel mineralization. Further studies are required to clarify the molecular background of the effects of PACAP on tooth development.
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Yin X, Li J, Salmon B, Huang L, Lim WH, Liu B, Hunter DJ, Ransom RC, Singh G, Gillette M, Zou S, Helms JA. Wnt Signaling and Its Contribution to Craniofacial Tissue Homeostasis. J Dent Res 2015; 94:1487-94. [PMID: 26285808 DOI: 10.1177/0022034515599772] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
A new field of dental medicine seeks to exploit nature's solution for repairing damaged tissues, through the process of regeneration. Most adult mammalian tissues have limited regenerative capacities, but in lower vertebrates, the molecular machinery for regeneration is an elemental part of their genetic makeup. Accumulating data suggest that the molecular pathways responsible for the regenerative capacity of teleosts, amphibians, and reptiles have fallen into disuse in mammals but that they can be "jumpstarted" by the selective activation of key molecules. The Wnt family of secreted proteins constitutes one such critical pathway: Wnt proteins rank among the most potent and ubiquitous stem cell self-renewing factors, with tremendous potential for promoting human tissue regeneration. Wnt reporter and lineage-tracing strains of mice have been employed to create molecular maps of Wnt responsiveness in the craniofacial tissues, and these patterns of Wnt signaling colocalize with stem/progenitor populations in the rodent incisor apex, the dental pulp, the alveolar bone, the periodontal ligament, the cementum, and oral mucosa. The importance of Wnt signaling in both the maintenance and healing of these craniofacial tissues is summarized, and the therapeutic potential of Wnt-based strategies to accelerate healing through activation of endogenous stem cells is highlighted.
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Affiliation(s)
- X Yin
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford, CA, USA
| | - J Li
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford, CA, USA
| | - B Salmon
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford, CA, USA Dental School, University Paris Descartes PRES Sorbonne Paris Cite, Montrouge, France; and AP-HP Odontology Department Bretonneau, Hopitaux Universitaires Paris Nord Val de Seine, Paris, France
| | - L Huang
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford, CA, USA Orthodontic Department, Stomatology Hospital of Chongqing Medical University; Chongqing Key Laboratory of Oral Disease and Biomedical Sciences; and Chongqing Municipal Key Laboratory, Chongqing, China
| | - W H Lim
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford, CA, USA Department of Orthodontics, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, Korea
| | - B Liu
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford, CA, USA
| | - D J Hunter
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford, CA, USA
| | - R C Ransom
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford, CA, USA
| | - G Singh
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford, CA, USA
| | - M Gillette
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford, CA, USA
| | - S Zou
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - J A Helms
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford, CA, USA
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Balic A, Thesleff I. Tissue Interactions Regulating Tooth Development and Renewal. Curr Top Dev Biol 2015; 115:157-86. [DOI: 10.1016/bs.ctdb.2015.07.006] [Citation(s) in RCA: 176] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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