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Gene Lee - One of the best experts on this subject based on the ideXlab platform.

  • Establishment of Hertwig's Epithelial Root Sheath/Epithelial rests of Malassez cell line from human periodontium.
    Molecules and cells, 2014
    Co-Authors: Hyun Nam, Joo-cheol Park, Byoungmoo Seo, Ji-hye Kim, Jae-won Kim, Jung-wook Kim, Gene Lee
    Abstract:

    Human Hertwig’s Epithelial Root Sheath/Epithelial rests of Malassez (HERS/ERM) cells are Epithelial remnants of teeth residing in the periodontium. Although the functional roles of HERS/ERM cells have yet to be elucidated, they are a unique Epithelial cell population in adult teeth and are reported to have stem cell characteristics. Therefore, HERS/ERM cells might play a role as an Epithelial component for the repair or regeneration of dental hard tissues; however, they are very rare population in periodontium and the primary isolation of them is considered to be difficult. To overcome these problems, we immortalized primary HERS/ERM cells isolated from human periodontium using SV40 large T antigen (SV40 LT) and performed a characterization of the immortalized cell line. Primary HERS/ERM cells could not be maintained for more than 6 passages; however, immortalized HERS/ERM cells were maintained for more than 20 passages. There were no differences in the morphological and immunophenotypic characteristics of HERS/ERM cells and immortalized HERS/ERM cells. The expression of Epithelial stem cell and embryonic stem cell markers was maintained in immortalized HERS/ERM cells. Moreover, immortalized HERS/ERM cells could acquire mesenchymal phenotypes through the Epithelial-mesenchymal transition via TGF-β1. In conclusion, we established an immortalized human HERS/ERM cell line with SV40 LT and expect this cell line to contribute to the understanding of the functional roles of HERS/ERM cells and the tissue engineering of teeth.

  • establishment of hertwig s Epithelial Root Sheath Epithelial rests of malassez cell line from human periodontium
    Molecules and Cells, 2014
    Co-Authors: Hyun Nam, Joo-cheol Park, Byoungmoo Seo, Ji-hye Kim, Jae-won Kim, Jung-wook Kim, Gene Lee
    Abstract:

    Human Hertwig’s Epithelial Root Sheath/Epithelial rests of Malassez (HERS/ERM) cells are Epithelial remnants of teeth residing in the periodontium. Although the functional roles of HERS/ERM cells have yet to be elucidated, they are a unique Epithelial cell population in adult teeth and are reported to have stem cell characteristics. Therefore, HERS/ERM cells might play a role as an Epithelial component for the repair or regeneration of dental hard tissues; however, they are very rare population in periodontium and the primary isolation of them is considered to be difficult. To overcome these problems, we immortalized primary HERS/ERM cells isolated from human periodontium using SV40 large T antigen (SV40 LT) and performed a characterization of the immortalized cell line. Primary HERS/ERM cells could not be maintained for more than 6 passages; however, immortalized HERS/ERM cells were maintained for more than 20 passages. There were no differences in the morphological and immunophenotypic characteristics of HERS/ERM cells and immortalized HERS/ERM cells. The expression of Epithelial stem cell and embryonic stem cell markers was maintained in immortalized HERS/ERM cells. Moreover, immortalized HERS/ERM cells could acquire mesenchymal phenotypes through the Epithelial-mesenchymal transition via TGF-β1. In conclusion, we established an immortalized human HERS/ERM cell line with SV40 LT and expect this cell line to contribute to the understanding of the functional roles of HERS/ERM cells and the tissue engineering of teeth.

  • dental follicle cells and cementoblasts induce apoptosis of ameloblast lineage and hertwig s Epithelial Root Sheath Epithelial rests of malassez cells through the fas fas ligand pathway
    European Journal of Oral Sciences, 2012
    Co-Authors: Jihyun Lee, Dongseol Lee, Hyun Nam, Gene Lee, Byoungmoo Seo, Youngsik Cho, Hyunsook Bae, Joo-cheol Park
    Abstract:

    Lee J-H, Lee D-S, Nam H, Lee G, Seo B-M, Cho Y-S, Bae H-S, Park J-C. Dental follicle cells and cementoblasts induce apoptosis of ameloblast-lineage and Hertwig’s Epithelial Root Sheath/Epithelial rests of Malassez cells through the Fas–Fas ligand pathway. Eur J Oral Sci 2012; 120: 29–37. © 2011 Eur J Oral Sci Hertwig’s Epithelial Root Sheath (HERS), Epithelial rests of Malassez (ERM) cells, and reduced ameloblasts undergo apoptosis during tooth development. This study examined the effects of dental follicle cells and cementoblasts on the apoptosis of ameloblast-lineage and HERS/ERM cells derived from the enamel organ. We also elucidated the induction pathways and identified the apoptotic pathway involved in this process. Here, we showed terminal deoxynucleotidyl transferase-mediated biotin–dUTP nick-end labeling (TUNEL)-positive HERS cells and reduced ameloblasts near dental follicle cells during tooth development. Co-culturing ameloblast-lineage cell line (ALC) ameloblasts and HERS/ERM cells with either dental follicle cells or OCCM-30 cementoblasts markedly enhanced the apoptosis of ameloblasts and HERS/ERM cells compared with cells cultured alone. However, dental follicle cells and cementoblasts did not modulate the apoptotic responses of co-cultured non-odontogenic MCF10A or KB cells. When ameloblasts + HERS and cementoblasts + dental follicle cells were co-cultured, the expression of Fas ligand (FasL) increased in cementoblasts + dental follicle cells, while the expression of Fas increased in ameloblasts + HERS. Interestingly, recombinant FasL induced ameloblast apoptosis while the cementoblast-induced ameloblast apoptosis was suppressed by the Fas/FasL antagonist Kp7-6. These results suggest that during tooth development, dental follicle cells and cementoblasts induce apoptosis of ameloblast-lineage and HERS/ERM cells through the Fas–FasL pathway, but do not induce the apoptosis of non-odontogenic Epithelial cells.

  • Dental follicle cells and cementoblasts induce apoptosis of ameloblast‐lineage and Hertwig’s Epithelial Root Sheath/Epithelial rests of Malassez cells through the Fas–Fas ligand pathway
    European journal of oral sciences, 2011
    Co-Authors: Jihyun Lee, Dongseol Lee, Hyun Nam, Gene Lee, Byoungmoo Seo, Youngsik Cho, Hyunsook Bae, Joo-cheol Park
    Abstract:

    Lee J-H, Lee D-S, Nam H, Lee G, Seo B-M, Cho Y-S, Bae H-S, Park J-C. Dental follicle cells and cementoblasts induce apoptosis of ameloblast-lineage and Hertwig’s Epithelial Root Sheath/Epithelial rests of Malassez cells through the Fas–Fas ligand pathway. Eur J Oral Sci 2012; 120: 29–37. © 2011 Eur J Oral Sci Hertwig’s Epithelial Root Sheath (HERS), Epithelial rests of Malassez (ERM) cells, and reduced ameloblasts undergo apoptosis during tooth development. This study examined the effects of dental follicle cells and cementoblasts on the apoptosis of ameloblast-lineage and HERS/ERM cells derived from the enamel organ. We also elucidated the induction pathways and identified the apoptotic pathway involved in this process. Here, we showed terminal deoxynucleotidyl transferase-mediated biotin–dUTP nick-end labeling (TUNEL)-positive HERS cells and reduced ameloblasts near dental follicle cells during tooth development. Co-culturing ameloblast-lineage cell line (ALC) ameloblasts and HERS/ERM cells with either dental follicle cells or OCCM-30 cementoblasts markedly enhanced the apoptosis of ameloblasts and HERS/ERM cells compared with cells cultured alone. However, dental follicle cells and cementoblasts did not modulate the apoptotic responses of co-cultured non-odontogenic MCF10A or KB cells. When ameloblasts + HERS and cementoblasts + dental follicle cells were co-cultured, the expression of Fas ligand (FasL) increased in cementoblasts + dental follicle cells, while the expression of Fas increased in ameloblasts + HERS. Interestingly, recombinant FasL induced ameloblast apoptosis while the cementoblast-induced ameloblast apoptosis was suppressed by the Fas/FasL antagonist Kp7-6. These results suggest that during tooth development, dental follicle cells and cementoblasts induce apoptosis of ameloblast-lineage and HERS/ERM cells through the Fas–FasL pathway, but do not induce the apoptosis of non-odontogenic Epithelial cells.

  • Expression profile of the stem cell markers in human Hertwig’s Epithelial Root Sheath/Epithelial rests of Malassez cells
    Molecules and cells, 2011
    Co-Authors: Hyun Nam, Joo-cheol Park, Byoungmoo Seo, Jae-won Kim, Jung-wook Kim, Jaewan Park, Jae Cheoun Lee, Gene Lee
    Abstract:

    Hertwig’s Epithelial Root Sheath/Epithelial rests of Malassez (HERS/ERM) cells are unique Epithelial cells in the periodontal ligament. They remain in periodontal tissues through-out the adult life, and it is expected that their functional role is to maintain the homeostasis of the periodontium through reciprocal interactions with other periodontal cells. In this study, we investigated whether HERS/ERM cells have primitive stem cell characteristics: those of embryonic stem cells as well as of Epithelial stem cells. Primary HERS/ERM cells had typical Epithelial cell morphology and characteristics and they maintained for more than five passages. They expressed Epithelial stem cell-related genes: ABCG2, ANp63, p75, EpCAM, and Bmi-1. Moreover, the expression of embryonic stem cell markers such as Oct-4, Nanog, and SSEA-4 were detected. Next, we investigated whether the expression of these stem cell markers was maintained during the sub-culture process. HERS/ERM cells showed different expression levels of these stemness genes at each passage, but their expression was maintained throughout the passages. Taken together, our data suggest that a primary culture of HERS/ERM cells contains a population of primitive stem cells that express Epithelial stem cell markers and embryonic stem cell markers. Furthermore, these cell populations were maintained during the sub-culturing process in our culture conditions. Therefore, our findings suggest that there is a strong possibility of accomplishing cementum tissue engineering with HERS/ERM cells.

Weidong Tian - One of the best experts on this subject based on the ideXlab platform.

  • immortalized hertwig s Epithelial Root Sheath cell line works as model for Epithelial mesenchymal interaction during tooth Root formation
    Journal of Cellular Physiology, 2020
    Co-Authors: Sicheng Zhang, Guoqing Chen, Weihua Guo, Shikai Wang, Yan Yang, Weidong Tian
    Abstract:

    Hertwig's Epithelial Root Sheath (HERS) is critical for Epithelial-mesenchymal interaction (EMI) during tooth Root formation. However, the exact roles of HERS in odontogenic differentiation by EMI have not been well characterized, because primary HERS cells are difficult to obtain. Immortalized cell lines constitute crucial scientific tools, while there are few HERS cell lines available. Our previous study has successfully established immortalized HERS cell lines. Here, we confirmed the phenotype of our HERS-H1 by verifying its characteristics and functions in odontogenic differentiation through EMI. The HERS-H1-conditioned medium (CM-H1) effectively enhanced odontogenic differentiation of dental papilla cells (DPCs) in vitro. Furthermore, Smad4 and p-Smad1/5/8 were significantly activated in DPCs treated with CM-H1, and this activation was attenuated by noggin. In vivo, our implanted recombinants of HERS-H1 and DPCs exhibited mineralized tissue formation and expression of Smad4, p-Smad1/5/8, and odontogenic differentiation markers. Our results indicated that HERS-H1 promoted DPCs odontoblastic differentiation via bone morphogenetic protein/Smad signaling. HERS-H1 exhibits relevant key molecular characteristics and constitutes a new biological model for basic research on HERS and the dental EMI during Root development and regeneration.

  • Immortalized Hertwig's Epithelial Root Sheath cell line works as model for Epithelial–mesenchymal interaction during tooth Root formation
    Journal of cellular physiology, 2019
    Co-Authors: Sicheng Zhang, Guoqing Chen, Weihua Guo, Shikai Wang, Yan Yang, Weidong Tian
    Abstract:

    Hertwig's Epithelial Root Sheath (HERS) is critical for Epithelial-mesenchymal interaction (EMI) during tooth Root formation. However, the exact roles of HERS in odontogenic differentiation by EMI have not been well characterized, because primary HERS cells are difficult to obtain. Immortalized cell lines constitute crucial scientific tools, while there are few HERS cell lines available. Our previous study has successfully established immortalized HERS cell lines. Here, we confirmed the phenotype of our HERS-H1 by verifying its characteristics and functions in odontogenic differentiation through EMI. The HERS-H1-conditioned medium (CM-H1) effectively enhanced odontogenic differentiation of dental papilla cells (DPCs) in vitro. Furthermore, Smad4 and p-Smad1/5/8 were significantly activated in DPCs treated with CM-H1, and this activation was attenuated by noggin. In vivo, our implanted recombinants of HERS-H1 and DPCs exhibited mineralized tissue formation and expression of Smad4, p-Smad1/5/8, and odontogenic differentiation markers. Our results indicated that HERS-H1 promoted DPCs odontoblastic differentiation via bone morphogenetic protein/Smad signaling. HERS-H1 exhibits relevant key molecular characteristics and constitutes a new biological model for basic research on HERS and the dental EMI during Root development and regeneration.

  • Development of immortalized Hertwig’s Epithelial Root Sheath cell lines for cementum and dentin regeneration
    Stem cell research & therapy, 2019
    Co-Authors: Sicheng Zhang, Guoqing Chen, Weihua Guo, Zirui Zhang, Weidong Tian
    Abstract:

    Hertwig’s Epithelial Root Sheath (HERS) is important in guiding tooth Root formation by differentiating into cementoblasts through Epithelial–mesenchymal transition (EMT) and inducing odontoblastic differentiation of dental papilla through Epithelial–mesenchymal interaction (EMI) during the tooth Root development. Thus, HERS cells are critical for cementum and dentin formation and might be a potential cell source to achieve tooth Root regeneration. However, limited availability and lifespan of primary HERS cells may represent an obstacle for biological investigation and therapeutic use of tooth tissue engineering. Therefore, we constructed, characterized, and tested the functionality of immortalized cell lines in order to produce a more readily available alternative to HERS cells. Primary HERS cells were immortalized via infection with lentivirus vector containing the gene encoding simian virus 40 Large T Antigen (SV40LT). Immortalized HERS cell subclones were isolated using a limiting dilution method, and subclones named HERS-H1 and HERS-C2 cells were isolated. The characteristics of HERS-H1 and HERS-C2 cells, including cell proliferation, ability of Epithelial–mesenchymal transformation and Epithelial–mesenchymal interaction, were determined by CCK-8 assay, immunofluorescence staining, and real-time PCR. The cell differentiation into cementoblast-like cells or periodontal fibroblast-like cells was confirmed in vivo. And the inductive influence of the cell lines on dental papilla cells (DPCs) was also confirmed in vivo. HERS-H1 and HERS-C2 cells share some common features with primary HERS cells such as Epithelial-like morphology, positive expression of CK14, E-Cadherin, and Vimentin, and undergoing EMT in response to TGF-beta. HERS-C2 cells showed the EMT characteristics and could differentiate into cementum-forming cells in vitro and generate cementum-like tissue in vivo. HERS-H1 could induce the differentiation of DPCs into odontoblasts in vitro and generation of dentin-like tissue in vivo. We successfully isolated and characterized novel cell lines representing two key features of HERS cells during the tooth Root development and which were useful substitutes for primary HERS cells, thereby providing a biologically relevant, unlimited cell source for studies on cell biology, developmental biology, and tooth Root regeneration.

  • development of immortalized hertwig s Epithelial Root Sheath cell lines for cementum and dentin regeneration
    Stem Cell Research & Therapy, 2019
    Co-Authors: Sicheng Zhang, Guoqing Chen, Weihua Guo, Zirui Zhang, Weidong Tian
    Abstract:

    Hertwig’s Epithelial Root Sheath (HERS) is important in guiding tooth Root formation by differentiating into cementoblasts through Epithelial–mesenchymal transition (EMT) and inducing odontoblastic differentiation of dental papilla through Epithelial–mesenchymal interaction (EMI) during the tooth Root development. Thus, HERS cells are critical for cementum and dentin formation and might be a potential cell source to achieve tooth Root regeneration. However, limited availability and lifespan of primary HERS cells may represent an obstacle for biological investigation and therapeutic use of tooth tissue engineering. Therefore, we constructed, characterized, and tested the functionality of immortalized cell lines in order to produce a more readily available alternative to HERS cells. Primary HERS cells were immortalized via infection with lentivirus vector containing the gene encoding simian virus 40 Large T Antigen (SV40LT). Immortalized HERS cell subclones were isolated using a limiting dilution method, and subclones named HERS-H1 and HERS-C2 cells were isolated. The characteristics of HERS-H1 and HERS-C2 cells, including cell proliferation, ability of Epithelial–mesenchymal transformation and Epithelial–mesenchymal interaction, were determined by CCK-8 assay, immunofluorescence staining, and real-time PCR. The cell differentiation into cementoblast-like cells or periodontal fibroblast-like cells was confirmed in vivo. And the inductive influence of the cell lines on dental papilla cells (DPCs) was also confirmed in vivo. HERS-H1 and HERS-C2 cells share some common features with primary HERS cells such as Epithelial-like morphology, positive expression of CK14, E-Cadherin, and Vimentin, and undergoing EMT in response to TGF-beta. HERS-C2 cells showed the EMT characteristics and could differentiate into cementum-forming cells in vitro and generate cementum-like tissue in vivo. HERS-H1 could induce the differentiation of DPCs into odontoblasts in vitro and generation of dentin-like tissue in vivo. We successfully isolated and characterized novel cell lines representing two key features of HERS cells during the tooth Root development and which were useful substitutes for primary HERS cells, thereby providing a biologically relevant, unlimited cell source for studies on cell biology, developmental biology, and tooth Root regeneration.

  • Development of immortalized Hertwig’s Epithelial Root Sheath cell lines for cementum and dentin regeneration
    BMC, 2019
    Co-Authors: Sicheng Zhang, Guoqing Chen, Weihua Guo, Zirui Zhang, Weidong Tian
    Abstract:

    Abstract Background Hertwig’s Epithelial Root Sheath (HERS) is important in guiding tooth Root formation by differentiating into cementoblasts through Epithelial–mesenchymal transition (EMT) and inducing odontoblastic differentiation of dental papilla through Epithelial–mesenchymal interaction (EMI) during the tooth Root development. Thus, HERS cells are critical for cementum and dentin formation and might be a potential cell source to achieve tooth Root regeneration. However, limited availability and lifespan of primary HERS cells may represent an obstacle for biological investigation and therapeutic use of tooth tissue engineering. Therefore, we constructed, characterized, and tested the functionality of immortalized cell lines in order to produce a more readily available alternative to HERS cells. Methods Primary HERS cells were immortalized via infection with lentivirus vector containing the gene encoding simian virus 40 Large T Antigen (SV40LT). Immortalized HERS cell subclones were isolated using a limiting dilution method, and subclones named HERS-H1 and HERS-C2 cells were isolated. The characteristics of HERS-H1 and HERS-C2 cells, including cell proliferation, ability of Epithelial–mesenchymal transformation and Epithelial–mesenchymal interaction, were determined by CCK-8 assay, immunofluorescence staining, and real-time PCR. The cell differentiation into cementoblast-like cells or periodontal fibroblast-like cells was confirmed in vivo. And the inductive influence of the cell lines on dental papilla cells (DPCs) was also confirmed in vivo. Results HERS-H1 and HERS-C2 cells share some common features with primary HERS cells such as Epithelial-like morphology, positive expression of CK14, E-Cadherin, and Vimentin, and undergoing EMT in response to TGF-beta. HERS-C2 cells showed the EMT characteristics and could differentiate into cementum-forming cells in vitro and generate cementum-like tissue in vivo. HERS-H1 could induce the differentiation of DPCs into odontoblasts in vitro and generation of dentin-like tissue in vivo. Conclusions We successfully isolated and characterized novel cell lines representing two key features of HERS cells during the tooth Root development and which were useful substitutes for primary HERS cells, thereby providing a biologically relevant, unlimited cell source for studies on cell biology, developmental biology, and tooth Root regeneration

Naoki Fujiwara - One of the best experts on this subject based on the ideXlab platform.

  • Hertwig's Epithelial Root Sheath cells contribute to formation of periodontal ligament through Epithelial-mesenchymal transition by TGF-β.
    Biomedical research (Tokyo Japan), 2017
    Co-Authors: Satoshi Itaya, Keishi Otsu, Naoki Fujiwara, Kyoko Oka, Kayoko Ogata, Shougo Tamura, Michiko Kira-tatsuoka, Eichi Tsuruga, Masao Ozaki, Hidemitsu Harada
    Abstract:

    In tooth Root development, periodontal ligament (PDL) and cementum are formed by the coordination with the fragmentation of Hertwig's Epithelial Root Sheath (HERS) and the differentiation of dental follicle mesenchymal cells. However, the function of the dental Epithelial cells after HERS fragmentation in the PDL is not fully understood. Here, we found that TGF-β regulated HERS fragmentation via Epithelial-mesenchymal transition (EMT), and the fragmented Epithelial cells differentiated into PDL fibroblastic cells with expressing of PDL extracellular matrix (ECM). In the histochemical analysis, TGF-β was expressed in odontoblast layer adjacent of HERS during Root development. Periostin expression was detected around fragmented Epithelial cells on the Root surface, but not in HERS. In the experiment using an established mouse HERS cell line (HERS01a), TGF-β1 treatment decreased E-cadherin and relatively increased N-cadherin expression. TGF-β1 treatment in HERS01a induced further expression of important ECM proteins for acellular cementum and PDL development such as fibronectin and periostin. Taken together, activation of TGF-βsignaling induces HERS fragmentation through EMT and the fragmented HERS cells contribute to formation of PDL and acellular cementum through periostin and fibronectin expression.

  • regulatory mechanisms of hertwig s Epithelial Root Sheath formation and anomaly correlated with Root length
    Experimental Cell Research, 2014
    Co-Authors: Mika Kumakamisakano, Keishi Otsu, Naoki Fujiwara, Hidemitsu Harada
    Abstract:

    Teeth are composed of two domains, the enamel-covered crown and cementum-covered Root. The mechanism for determining the transition from crown to Root is important for understanding Root anomaly diseases. Hertwig׳s Epithelial Root Sheath (HERS) is derived from the dental epithelium and is known to drive the growth of Root dentin and periodontal tissue. Some clinical cases of hypoplastic tooth Root are caused by the cessation of HERS development. Understanding the mechanisms of HERS development will contribute to the study of the disease and dental regenerative medicine. However, the developmental biology of tooth Root formation has not been fully studied, particularly regarding HERS formation. Here, we describe the mechanisms of HERS formation on the basis of analysis of cell dynamics using imaging and summarize how the growth factor and its receptor regulate cell behavior of the dental epithelium.

  • Regulatory mechanisms of Hertwig׳s Epithelial Root Sheath formation and anomaly correlated with Root length.
    Experimental cell research, 2014
    Co-Authors: Mika Kumakami-sakano, Keishi Otsu, Naoki Fujiwara, Hidemitsu Harada
    Abstract:

    Teeth are composed of two domains, the enamel-covered crown and cementum-covered Root. The mechanism for determining the transition from crown to Root is important for understanding Root anomaly diseases. Hertwig׳s Epithelial Root Sheath (HERS) is derived from the dental epithelium and is known to drive the growth of Root dentin and periodontal tissue. Some clinical cases of hypoplastic tooth Root are caused by the cessation of HERS development. Understanding the mechanisms of HERS development will contribute to the study of the disease and dental regenerative medicine. However, the developmental biology of tooth Root formation has not been fully studied, particularly regarding HERS formation. Here, we describe the mechanisms of HERS formation on the basis of analysis of cell dynamics using imaging and summarize how the growth factor and its receptor regulate cell behavior of the dental epithelium.

  • cell dynamics in cervical loop epithelium during transition from crown to Root implications for hertwig s Epithelial Root Sheath formation
    Journal of Periodontal Research, 2013
    Co-Authors: Masaaki Sakano, Keishi Otsu, Naoki Fujiwara, Satoshi Fukumoto, Aya Yamada, Hidemitsu Harada
    Abstract:

    Background and Objective Some clinical cases of hypoplastic tooth Root are congenital. Because the formation of Hertwig's Epithelial Root Sheath (HERS) is an important event for Root development and growth, we have considered that understanding the HERS developmental mechanism contributes to elucidate the causal factors of the disease. To find integrant factors and phenomenon for HERS development and growth, we studied the proliferation and mobility of the cervical loop (CL). Material and Methods We observed the cell movement of CL by the DiI labeling and organ culture system. To examine cell proliferation, we carried out immunostaining of CL and HERS using anti-Ki67 antibody. Cell motility in CL was observed by tooth germ slice organ culture using green fluorescent protein mouse. We also examined the expression of paxillin associated with cell movement. Results Imaging using DiI labeling showed that, at the apex of CL, the epithelium elongated in tandem with the growth of outer enamel epithelium (OEE). Cell proliferation assay using Ki67 immunostaining showed that OEE divided more actively than inner enamel epithelium (IEE) at the onset of HERS formation. Live imaging suggested that mobility of the OEE and cells in the apex of CL were more active than in IEE. The expression of paxillin was observed strongly in OEE and the apex of CL. Conclusion The more active growth and movement of OEE cells contributed to HERS formation after reduction of the growth of IEE. The expression pattern of paxillin was involved in the active movement of OEE and HERS. The results will contribute to understand the HERS formation mechanism and elucidate the cause of anomaly Root.

  • Promotional effects of vasoactive intestinal peptide on the development of rodent Hertwig's Epithelial Root Sheath
    Congenital anomalies, 2012
    Co-Authors: Nobuyuki Kawashima, Naoki Fujiwara, Hidemitsu Harada, Masato S. Ota, Hideaki Suda
    Abstract:

    Hertwig's Epithelial Root Sheath (HERS), a bilayered Epithelial cell Sheath located at the cervical loop of the enamel organ in a developing tooth, is at the forefront of Root formation. However, little is known about the exact mechanisms that regulate the development of HERS. The neuropeptide vasoactive intestinal peptide (VIP) is involved in the development of various tissues and cells. In this study, we investigated the roles of VIP in HERS development. VIP-immunoreactive nerve fibers were found in the dental pulp and around the Root apex of the tooth, while the expression of VIP receptor 1 (VPAC1) was observed in HERS. The expression level of VPAC1 correlated with the development of HERS and was elevated at postnatal days 14 and 21. Using ex vivo cultures of neonatal tooth germs, VIP enhanced the elongation and proliferation of HERS. In vitro, VIP also promoted the proliferation of cells from the HERS-derived cell line, HERS01a cells, and upregulated the mRNA expression of cytokeratin 14 and vimentin (typical molecular markers of HERS) in these cells. These results suggest that VIP may be an essential factor for HERS development.

Hidemitsu Harada - One of the best experts on this subject based on the ideXlab platform.

  • Cell dynamics in Hertwig's Epithelial Root Sheath are regulated by β-catenin activity during tooth Root development
    Journal of cellular physiology, 2020
    Co-Authors: Siqin Yang, Hidemitsu Harada, Hwajung Choi, Tak-heun Kim, Ju-kyung Jeong, Yudong Liu, Eui-sic Cho
    Abstract:

    β-catenin, a key mediator of Wnt signaling, plays multiple roles in tooth development. However, the role of β-catenin in Hertwig's Epithelial Root Sheath (HERS) during Root formation remains unclear. In this study, we generated inducible tissue-specific β-catenin conditional knockout mice (Ctnnb1i∆shh ) to investigate how β-catenin in HERS affects tooth Root development. The inactivation of β-catenin in HERS led to interrupted Root elongation due to premature disruption of HERS. This phenotype was accompanied by reduced cell-cell adhesion and decreased expression of junctional proteins, as well as increased Epithelial-to-mesenchymal transition of HERS cells upon β-catenin depletion. Accordingly, stabilization of β-catenin in HERS (Catnbi∆shh ) led to the formation of unfragmented HERS and resulted in the failure of HERS dissociation, with increased expression of junctional proteins. Our results suggest that fine control of β-catenin is important for HERS to guide Root formation through regulating its structural integrity.

  • Hertwig's Epithelial Root Sheath cells contribute to formation of periodontal ligament through Epithelial-mesenchymal transition by TGF-β.
    Biomedical research (Tokyo Japan), 2017
    Co-Authors: Satoshi Itaya, Keishi Otsu, Naoki Fujiwara, Kyoko Oka, Kayoko Ogata, Shougo Tamura, Michiko Kira-tatsuoka, Eichi Tsuruga, Masao Ozaki, Hidemitsu Harada
    Abstract:

    In tooth Root development, periodontal ligament (PDL) and cementum are formed by the coordination with the fragmentation of Hertwig's Epithelial Root Sheath (HERS) and the differentiation of dental follicle mesenchymal cells. However, the function of the dental Epithelial cells after HERS fragmentation in the PDL is not fully understood. Here, we found that TGF-β regulated HERS fragmentation via Epithelial-mesenchymal transition (EMT), and the fragmented Epithelial cells differentiated into PDL fibroblastic cells with expressing of PDL extracellular matrix (ECM). In the histochemical analysis, TGF-β was expressed in odontoblast layer adjacent of HERS during Root development. Periostin expression was detected around fragmented Epithelial cells on the Root surface, but not in HERS. In the experiment using an established mouse HERS cell line (HERS01a), TGF-β1 treatment decreased E-cadherin and relatively increased N-cadherin expression. TGF-β1 treatment in HERS01a induced further expression of important ECM proteins for acellular cementum and PDL development such as fibronectin and periostin. Taken together, activation of TGF-βsignaling induces HERS fragmentation through EMT and the fragmented HERS cells contribute to formation of PDL and acellular cementum through periostin and fibronectin expression.

  • regulatory mechanisms of hertwig s Epithelial Root Sheath formation and anomaly correlated with Root length
    Experimental Cell Research, 2014
    Co-Authors: Mika Kumakamisakano, Keishi Otsu, Naoki Fujiwara, Hidemitsu Harada
    Abstract:

    Teeth are composed of two domains, the enamel-covered crown and cementum-covered Root. The mechanism for determining the transition from crown to Root is important for understanding Root anomaly diseases. Hertwig׳s Epithelial Root Sheath (HERS) is derived from the dental epithelium and is known to drive the growth of Root dentin and periodontal tissue. Some clinical cases of hypoplastic tooth Root are caused by the cessation of HERS development. Understanding the mechanisms of HERS development will contribute to the study of the disease and dental regenerative medicine. However, the developmental biology of tooth Root formation has not been fully studied, particularly regarding HERS formation. Here, we describe the mechanisms of HERS formation on the basis of analysis of cell dynamics using imaging and summarize how the growth factor and its receptor regulate cell behavior of the dental epithelium.

  • Regulatory mechanisms of Hertwig׳s Epithelial Root Sheath formation and anomaly correlated with Root length.
    Experimental cell research, 2014
    Co-Authors: Mika Kumakami-sakano, Keishi Otsu, Naoki Fujiwara, Hidemitsu Harada
    Abstract:

    Teeth are composed of two domains, the enamel-covered crown and cementum-covered Root. The mechanism for determining the transition from crown to Root is important for understanding Root anomaly diseases. Hertwig׳s Epithelial Root Sheath (HERS) is derived from the dental epithelium and is known to drive the growth of Root dentin and periodontal tissue. Some clinical cases of hypoplastic tooth Root are caused by the cessation of HERS development. Understanding the mechanisms of HERS development will contribute to the study of the disease and dental regenerative medicine. However, the developmental biology of tooth Root formation has not been fully studied, particularly regarding HERS formation. Here, we describe the mechanisms of HERS formation on the basis of analysis of cell dynamics using imaging and summarize how the growth factor and its receptor regulate cell behavior of the dental epithelium.

  • cell dynamics in cervical loop epithelium during transition from crown to Root implications for hertwig s Epithelial Root Sheath formation
    Journal of Periodontal Research, 2013
    Co-Authors: Masaaki Sakano, Keishi Otsu, Naoki Fujiwara, Satoshi Fukumoto, Aya Yamada, Hidemitsu Harada
    Abstract:

    Background and Objective Some clinical cases of hypoplastic tooth Root are congenital. Because the formation of Hertwig's Epithelial Root Sheath (HERS) is an important event for Root development and growth, we have considered that understanding the HERS developmental mechanism contributes to elucidate the causal factors of the disease. To find integrant factors and phenomenon for HERS development and growth, we studied the proliferation and mobility of the cervical loop (CL). Material and Methods We observed the cell movement of CL by the DiI labeling and organ culture system. To examine cell proliferation, we carried out immunostaining of CL and HERS using anti-Ki67 antibody. Cell motility in CL was observed by tooth germ slice organ culture using green fluorescent protein mouse. We also examined the expression of paxillin associated with cell movement. Results Imaging using DiI labeling showed that, at the apex of CL, the epithelium elongated in tandem with the growth of outer enamel epithelium (OEE). Cell proliferation assay using Ki67 immunostaining showed that OEE divided more actively than inner enamel epithelium (IEE) at the onset of HERS formation. Live imaging suggested that mobility of the OEE and cells in the apex of CL were more active than in IEE. The expression of paxillin was observed strongly in OEE and the apex of CL. Conclusion The more active growth and movement of OEE cells contributed to HERS formation after reduction of the growth of IEE. The expression pattern of paxillin was involved in the active movement of OEE and HERS. The results will contribute to understand the HERS formation mechanism and elucidate the cause of anomaly Root.

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  • Establishment of Hertwig's Epithelial Root Sheath/Epithelial rests of Malassez cell line from human periodontium.
    Molecules and cells, 2014
    Co-Authors: Hyun Nam, Joo-cheol Park, Byoungmoo Seo, Ji-hye Kim, Jae-won Kim, Jung-wook Kim, Gene Lee
    Abstract:

    Human Hertwig’s Epithelial Root Sheath/Epithelial rests of Malassez (HERS/ERM) cells are Epithelial remnants of teeth residing in the periodontium. Although the functional roles of HERS/ERM cells have yet to be elucidated, they are a unique Epithelial cell population in adult teeth and are reported to have stem cell characteristics. Therefore, HERS/ERM cells might play a role as an Epithelial component for the repair or regeneration of dental hard tissues; however, they are very rare population in periodontium and the primary isolation of them is considered to be difficult. To overcome these problems, we immortalized primary HERS/ERM cells isolated from human periodontium using SV40 large T antigen (SV40 LT) and performed a characterization of the immortalized cell line. Primary HERS/ERM cells could not be maintained for more than 6 passages; however, immortalized HERS/ERM cells were maintained for more than 20 passages. There were no differences in the morphological and immunophenotypic characteristics of HERS/ERM cells and immortalized HERS/ERM cells. The expression of Epithelial stem cell and embryonic stem cell markers was maintained in immortalized HERS/ERM cells. Moreover, immortalized HERS/ERM cells could acquire mesenchymal phenotypes through the Epithelial-mesenchymal transition via TGF-β1. In conclusion, we established an immortalized human HERS/ERM cell line with SV40 LT and expect this cell line to contribute to the understanding of the functional roles of HERS/ERM cells and the tissue engineering of teeth.

  • establishment of hertwig s Epithelial Root Sheath Epithelial rests of malassez cell line from human periodontium
    Molecules and Cells, 2014
    Co-Authors: Hyun Nam, Joo-cheol Park, Byoungmoo Seo, Ji-hye Kim, Jae-won Kim, Jung-wook Kim, Gene Lee
    Abstract:

    Human Hertwig’s Epithelial Root Sheath/Epithelial rests of Malassez (HERS/ERM) cells are Epithelial remnants of teeth residing in the periodontium. Although the functional roles of HERS/ERM cells have yet to be elucidated, they are a unique Epithelial cell population in adult teeth and are reported to have stem cell characteristics. Therefore, HERS/ERM cells might play a role as an Epithelial component for the repair or regeneration of dental hard tissues; however, they are very rare population in periodontium and the primary isolation of them is considered to be difficult. To overcome these problems, we immortalized primary HERS/ERM cells isolated from human periodontium using SV40 large T antigen (SV40 LT) and performed a characterization of the immortalized cell line. Primary HERS/ERM cells could not be maintained for more than 6 passages; however, immortalized HERS/ERM cells were maintained for more than 20 passages. There were no differences in the morphological and immunophenotypic characteristics of HERS/ERM cells and immortalized HERS/ERM cells. The expression of Epithelial stem cell and embryonic stem cell markers was maintained in immortalized HERS/ERM cells. Moreover, immortalized HERS/ERM cells could acquire mesenchymal phenotypes through the Epithelial-mesenchymal transition via TGF-β1. In conclusion, we established an immortalized human HERS/ERM cell line with SV40 LT and expect this cell line to contribute to the understanding of the functional roles of HERS/ERM cells and the tissue engineering of teeth.

  • dental follicle cells and cementoblasts induce apoptosis of ameloblast lineage and hertwig s Epithelial Root Sheath Epithelial rests of malassez cells through the fas fas ligand pathway
    European Journal of Oral Sciences, 2012
    Co-Authors: Jihyun Lee, Dongseol Lee, Hyun Nam, Gene Lee, Byoungmoo Seo, Youngsik Cho, Hyunsook Bae, Joo-cheol Park
    Abstract:

    Lee J-H, Lee D-S, Nam H, Lee G, Seo B-M, Cho Y-S, Bae H-S, Park J-C. Dental follicle cells and cementoblasts induce apoptosis of ameloblast-lineage and Hertwig’s Epithelial Root Sheath/Epithelial rests of Malassez cells through the Fas–Fas ligand pathway. Eur J Oral Sci 2012; 120: 29–37. © 2011 Eur J Oral Sci Hertwig’s Epithelial Root Sheath (HERS), Epithelial rests of Malassez (ERM) cells, and reduced ameloblasts undergo apoptosis during tooth development. This study examined the effects of dental follicle cells and cementoblasts on the apoptosis of ameloblast-lineage and HERS/ERM cells derived from the enamel organ. We also elucidated the induction pathways and identified the apoptotic pathway involved in this process. Here, we showed terminal deoxynucleotidyl transferase-mediated biotin–dUTP nick-end labeling (TUNEL)-positive HERS cells and reduced ameloblasts near dental follicle cells during tooth development. Co-culturing ameloblast-lineage cell line (ALC) ameloblasts and HERS/ERM cells with either dental follicle cells or OCCM-30 cementoblasts markedly enhanced the apoptosis of ameloblasts and HERS/ERM cells compared with cells cultured alone. However, dental follicle cells and cementoblasts did not modulate the apoptotic responses of co-cultured non-odontogenic MCF10A or KB cells. When ameloblasts + HERS and cementoblasts + dental follicle cells were co-cultured, the expression of Fas ligand (FasL) increased in cementoblasts + dental follicle cells, while the expression of Fas increased in ameloblasts + HERS. Interestingly, recombinant FasL induced ameloblast apoptosis while the cementoblast-induced ameloblast apoptosis was suppressed by the Fas/FasL antagonist Kp7-6. These results suggest that during tooth development, dental follicle cells and cementoblasts induce apoptosis of ameloblast-lineage and HERS/ERM cells through the Fas–FasL pathway, but do not induce the apoptosis of non-odontogenic Epithelial cells.

  • Dental follicle cells and cementoblasts induce apoptosis of ameloblast‐lineage and Hertwig’s Epithelial Root Sheath/Epithelial rests of Malassez cells through the Fas–Fas ligand pathway
    European journal of oral sciences, 2011
    Co-Authors: Jihyun Lee, Dongseol Lee, Hyun Nam, Gene Lee, Byoungmoo Seo, Youngsik Cho, Hyunsook Bae, Joo-cheol Park
    Abstract:

    Lee J-H, Lee D-S, Nam H, Lee G, Seo B-M, Cho Y-S, Bae H-S, Park J-C. Dental follicle cells and cementoblasts induce apoptosis of ameloblast-lineage and Hertwig’s Epithelial Root Sheath/Epithelial rests of Malassez cells through the Fas–Fas ligand pathway. Eur J Oral Sci 2012; 120: 29–37. © 2011 Eur J Oral Sci Hertwig’s Epithelial Root Sheath (HERS), Epithelial rests of Malassez (ERM) cells, and reduced ameloblasts undergo apoptosis during tooth development. This study examined the effects of dental follicle cells and cementoblasts on the apoptosis of ameloblast-lineage and HERS/ERM cells derived from the enamel organ. We also elucidated the induction pathways and identified the apoptotic pathway involved in this process. Here, we showed terminal deoxynucleotidyl transferase-mediated biotin–dUTP nick-end labeling (TUNEL)-positive HERS cells and reduced ameloblasts near dental follicle cells during tooth development. Co-culturing ameloblast-lineage cell line (ALC) ameloblasts and HERS/ERM cells with either dental follicle cells or OCCM-30 cementoblasts markedly enhanced the apoptosis of ameloblasts and HERS/ERM cells compared with cells cultured alone. However, dental follicle cells and cementoblasts did not modulate the apoptotic responses of co-cultured non-odontogenic MCF10A or KB cells. When ameloblasts + HERS and cementoblasts + dental follicle cells were co-cultured, the expression of Fas ligand (FasL) increased in cementoblasts + dental follicle cells, while the expression of Fas increased in ameloblasts + HERS. Interestingly, recombinant FasL induced ameloblast apoptosis while the cementoblast-induced ameloblast apoptosis was suppressed by the Fas/FasL antagonist Kp7-6. These results suggest that during tooth development, dental follicle cells and cementoblasts induce apoptosis of ameloblast-lineage and HERS/ERM cells through the Fas–FasL pathway, but do not induce the apoptosis of non-odontogenic Epithelial cells.

  • Expression profile of the stem cell markers in human Hertwig’s Epithelial Root Sheath/Epithelial rests of Malassez cells
    Molecules and cells, 2011
    Co-Authors: Hyun Nam, Joo-cheol Park, Byoungmoo Seo, Jae-won Kim, Jung-wook Kim, Jaewan Park, Jae Cheoun Lee, Gene Lee
    Abstract:

    Hertwig’s Epithelial Root Sheath/Epithelial rests of Malassez (HERS/ERM) cells are unique Epithelial cells in the periodontal ligament. They remain in periodontal tissues through-out the adult life, and it is expected that their functional role is to maintain the homeostasis of the periodontium through reciprocal interactions with other periodontal cells. In this study, we investigated whether HERS/ERM cells have primitive stem cell characteristics: those of embryonic stem cells as well as of Epithelial stem cells. Primary HERS/ERM cells had typical Epithelial cell morphology and characteristics and they maintained for more than five passages. They expressed Epithelial stem cell-related genes: ABCG2, ANp63, p75, EpCAM, and Bmi-1. Moreover, the expression of embryonic stem cell markers such as Oct-4, Nanog, and SSEA-4 were detected. Next, we investigated whether the expression of these stem cell markers was maintained during the sub-culture process. HERS/ERM cells showed different expression levels of these stemness genes at each passage, but their expression was maintained throughout the passages. Taken together, our data suggest that a primary culture of HERS/ERM cells contains a population of primitive stem cells that express Epithelial stem cell markers and embryonic stem cell markers. Furthermore, these cell populations were maintained during the sub-culturing process in our culture conditions. Therefore, our findings suggest that there is a strong possibility of accomplishing cementum tissue engineering with HERS/ERM cells.