Mesenchymal stem cells （MSCs） have been identified and isolated from dental tissues, including stem cells from apical papilla, which demonstrated the ability to differentiate into dentin-forming odontoblasts. The hi...Mesenchymal stem cells （MSCs） have been identified and isolated from dental tissues, including stem cells from apical papilla, which demonstrated the ability to differentiate into dentin-forming odontoblasts. The histone demethylase KDM6B （also known as JMJD3） was shown to play a key role in promoting osteogenic commitment by removing epigenetic marks H3K27me3 from the promoters of osteogenic genes. Whether KDM6B is involved in odontogenic differentiation of dental MSCs, however, is not known. Here, we explored the role of KDM6B in dental MSC fate determination into the odontogenic lineage. Using shRNA-expressing lentivirus, we performed KDM6B knockdown in dental MSCs and observed that KDM6B depletion leads to a significant reduction in alkaline phosphate （ALP） activity and in formation of mineralized nodules assessed by Alizarin Red staining. Additionally, mRNA expression of odontogenic marker gene SP7 （osterix, OSX）, as well as extracellular matrix genes BGLAP （osteoclacin, OCN） and SPP1 （osteopontin, OPN）, was suppressed by KDM6B depletion. When KDM6B was overexpressed in KDM6B-knockdown MSCs, odontogenic differentiation was restored, further confirming the facilitating role of KDM6B in odontogenic commitment. Mechanistically, KDM6B was recruited to bone morphogenic protein 2 （BMP2） promoters and the subsequent removal of silencing H3K27me3 marks led to the activation of this odontogenic master transcription gene. Taken together, our results demonstrated the critical role of a histone demethylase in the epigenetic regulation of odontogenic differentiation of dental MSCs. KDM6B may present as a potential therapeutic target in the regeneration of tooth structures and the repair of craniofacial defects.展开更多
Mesenchymal stem cells （MSCs） are characterized by their self-renewing capacity and differentiation potential into multiple tissues. Thus, management of the differentiation capacities of MSCs is important for MSC-ba...Mesenchymal stem cells （MSCs） are characterized by their self-renewing capacity and differentiation potential into multiple tissues. Thus, management of the differentiation capacities of MSCs is important for MSC-based regenerative medicine, such as craniofacial bone regeneration, and in new treatments for metabolic bone diseases, such as osteoporosis. In recent years, histone modification has been a growing topic in the field of MSC lineage specification, in which the Su（var）3-9, enhancer-of-zeste, trithorax （SET） domain-containing family and the Jumonji C （JmjC） domain-containing family represent the major histone lysine methyltransferases （KMTs） and histone lysine demethylases （KDMs）, respectively. In this review, we summarize the current understanding of the epigenetic mechanisms by which SET domain-containine KMTs and JmiC domain-containinlz KDMs balance the osteogenic and adipogenic differentiation of MSCs.展开更多
Mesenchymal stem cell （MSC）-mediated therapy has been shown to be clinically effective in regenerating tissue defects. For improved regenerative therapy, it is critical to isolate homogenous populations of MSCs with...Mesenchymal stem cell （MSC）-mediated therapy has been shown to be clinically effective in regenerating tissue defects. For improved regenerative therapy, it is critical to isolate homogenous populations of MSCs with high capacity to differentiate into appropriate tissues. The utilization of stem cell surface antigens provides a means to identify MSCs from various tissues. However, few surface markers that consistently isolate highly regenerative MSCs have been validated, making it challenging for routine clinical applications and making it all the more imperative to identify reliable surface markers. In this study, we used three surface marker combinations： CD51/CD140a, CD271, and STRO-1/CD146 for the isolation of homogenous populations of dental mesenchymal stem cells （DMSCs） from heterogeneous periodontal ligament cells （PDLCs）. Fluorescence-activated cell sorting analysis revealed that 24% of PDLCs were CD51＋/CD140a＋, 0.8% were CD271＋, and 2.4% were STRO-1＋/CD146＋. Sorted cell populations were further assessed for their multipotent properties by inducing osteogenic and chondrogenic differentiation. All three subsets of isolated DMSCs exhibited differentiation capacity into osteogenic and chondrogenic lineages but with varying degrees. CD271＋ DMSCs demonstrated the greatest osteogenic potential with strong induction of osteogenic markers such as DLX5, RUNX2, and BGLAP. Our study provides evidence that surface marker combinations used in this study are sufficient markers for the isolation of DMSCs from PDLCs. These results provide important insight into using specific surface markers for identifying homogenous populations of DMSCs for their improved utilization in regenerative medicine.展开更多
Mesenchymal stem cells(MSCs)derived from human embryonic stem cells(hESCs)have significant potential for cell-mediated bone regeneration.Our recent study revealed that inhibiting the epigenetic regulator EZH2 plays a ...Mesenchymal stem cells(MSCs)derived from human embryonic stem cells(hESCs)have significant potential for cell-mediated bone regeneration.Our recent study revealed that inhibiting the epigenetic regulator EZH2 plays a key role in promoting the mesodermal differentiation of hESCs.In this study,an epigenome-wide analysis of hESCs and MSCs revealed that growth differentiation factor 6(GDF6),which is involved in bone formation,was the most upregulated gene associated with MSCs compared to hESCs.Furthermore,we identified GDF6 as a repressive target of EZH2 and found that ectopic GDF6 selectively promoted hESC differentiation towards the mesodermal lineage and enriched the MSC population.Our results provide molecular insights governing the mesenchymal commitment of hESCs and identify an inducing factor that offers strong promise for the future of regenerative medicine.展开更多
Purpose: To establish a new coordinate system using the incisive canal and incisive foramen in cases confirmed to have root resorption in the maxillary incisor region by cone beam computed tomography (CBCT) to investi...Purpose: To establish a new coordinate system using the incisive canal and incisive foramen in cases confirmed to have root resorption in the maxillary incisor region by cone beam computed tomography (CBCT) to investigate the positions of the central and lateral incisor roots and erupting maxillary canine tooth crowns in the horizontal plane. Methods: Nine patients (two males;mean age: 10.5 years old) with suspected incisor root resorption due to erupting maxillary canines on panoramic X-ray images and in whom incisor root resorption was confirmed on CBCT images were evaluated. A control group of 12 patients with a supernumerary tooth on one side (three males;mean age: 8.6 years old) was also examined. X, Y, and Z-axes were defined, and the positions of the centers of the central incisor root (U1) and lateral incisor root (U2) and the canine cusp (U3) were examined, along with alveolar process width and length. Results: In the control group, U1, U2, and U3 were located within a certain range without overlap, while, in the incisor root resorption group, U3 overlapped with U1 and U2 and tended to deviate centrally. U2 tended to be located further posteriorly than U3. The anteroposterior diameter of the alveolar process was 1.2 mm shorter in the incisor root resorption group (p < 0.05). Conclusions: The risk of incisor root resorption accompanying canine eruption can be evaluated early by investigating the canine position on a horizontal plane established on the upper anterior tooth dentition CT images with a coordinate system using the incisive canal and incisive foramen.展开更多
The periodontal ligament (PDL) contains oxytalan fibers as well as collagen fibers, which helps it to withstand the mechanical stress to which it is constantly exposed. The oxytalan fibers are produced by PDL fibrobla...The periodontal ligament (PDL) contains oxytalan fibers as well as collagen fibers, which helps it to withstand the mechanical stress to which it is constantly exposed. The oxytalan fibers are produced by PDL fibroblasts. However, the arrangement of PDL fibroblasts and the orientation of oxytalan fibers relative to the fibroblast cell axis have not been investigated under the condition of mechanical stress. We hypothesized that such stress would alter the arrangement and orientation of these cells and their oxytalan fibers. The aim of this study was to evaluate the effects of stretching strain on PDL fibroblasts, focusing on the cellular arrangement and orientation of oxytalan fibers relative to the long cell axis in cell/matrix layers by staining the major component of the fibers, fibrillin-1. The angle between the long cell axis and the oxytalan fibers was approximately 70 degrees under both non-stretching and stretching conditions. Moreover, stretching induced the rearrangement of the cells. This is the first study to demonstrate that stretching induces the rearrangement of the PDL fibroblasts without altering the angle between the long cell axis and the oxytalan fibers. These results may reflect the orientation of oxytalan fibers in the PDL under the condition of mechanical stress.展开更多
Mesenchymal stem cells （MSCs） are a promising tool in regenerative medicine due to their capacity to differentiate into multiple lineages. In addition to MSCs isolated from bone marrow （BMSCs）, adult MSCs are isol...Mesenchymal stem cells （MSCs） are a promising tool in regenerative medicine due to their capacity to differentiate into multiple lineages. In addition to MSCs isolated from bone marrow （BMSCs）, adult MSCs are isolated from craniofacial tissues including dental pulp tissues （DPs） using various stem cell surface markers. However, there has been a lack of consensus on a set of surface makers that are reproducibly effective at isolating putative multipotent dental mesenchymal stem cel^s （~M^Cs）. II1 ~his stucly, we used clif^et（~nt combinations of surface markers （CD51/CD140a, CD271, and STRO-1/CD146） to isolate homogeneous populations of DMSCs from heterogeneous dental pulp cells （DPCs） obtained from DP and compared their capacity to undergo multilineage differentiation. Fluorescence-activated cell sorting revealed that 27.3% of DPCs were CD51＋/CD140a＋, 10.6% were CD271＋, and 0.3% were STRO-1＋/CD146＋. Under odontogenic conditions, all three subsets of isolated DMSCs exhibited differentiation capacity into odontogenic lineages. Among these isolated subsets of DMSCs, CD271＋ DMSCs demonstrated the greatest odontogenic potential. While all three combinations of surface markers in this study successfully isolated DMSCs from DPCs, the single CD271 marker presents the most effective stem cell surface marker for identification of DMSCs with high odontogenic potential. Isolated CD271＋ DMSCs could potentially be utilized for future clinical applications in dentistry and regenerative medicine.展开更多
文摘Mesenchymal stem cells （MSCs） have been identified and isolated from dental tissues, including stem cells from apical papilla, which demonstrated the ability to differentiate into dentin-forming odontoblasts. The histone demethylase KDM6B （also known as JMJD3） was shown to play a key role in promoting osteogenic commitment by removing epigenetic marks H3K27me3 from the promoters of osteogenic genes. Whether KDM6B is involved in odontogenic differentiation of dental MSCs, however, is not known. Here, we explored the role of KDM6B in dental MSC fate determination into the odontogenic lineage. Using shRNA-expressing lentivirus, we performed KDM6B knockdown in dental MSCs and observed that KDM6B depletion leads to a significant reduction in alkaline phosphate （ALP） activity and in formation of mineralized nodules assessed by Alizarin Red staining. Additionally, mRNA expression of odontogenic marker gene SP7 （osterix, OSX）, as well as extracellular matrix genes BGLAP （osteoclacin, OCN） and SPP1 （osteopontin, OPN）, was suppressed by KDM6B depletion. When KDM6B was overexpressed in KDM6B-knockdown MSCs, odontogenic differentiation was restored, further confirming the facilitating role of KDM6B in odontogenic commitment. Mechanistically, KDM6B was recruited to bone morphogenic protein 2 （BMP2） promoters and the subsequent removal of silencing H3K27me3 marks led to the activation of this odontogenic master transcription gene. Taken together, our results demonstrated the critical role of a histone demethylase in the epigenetic regulation of odontogenic differentiation of dental MSCs. KDM6B may present as a potential therapeutic target in the regeneration of tooth structures and the repair of craniofacial defects.
基金supported by the National Institute of Dental and Craniofacial Research grants, K08DE024603-02, DE019412, and DE01651a grant from 111 Project of MOE, Chinasupported by Open Fund of State Key Laboratory of Oral Diseases, Sichuan University
文摘Mesenchymal stem cells （MSCs） are characterized by their self-renewing capacity and differentiation potential into multiple tissues. Thus, management of the differentiation capacities of MSCs is important for MSC-based regenerative medicine, such as craniofacial bone regeneration, and in new treatments for metabolic bone diseases, such as osteoporosis. In recent years, histone modification has been a growing topic in the field of MSC lineage specification, in which the Su（var）3-9, enhancer-of-zeste, trithorax （SET） domain-containing family and the Jumonji C （JmjC） domain-containing family represent the major histone lysine methyltransferases （KMTs） and histone lysine demethylases （KDMs）, respectively. In this review, we summarize the current understanding of the epigenetic mechanisms by which SET domain-containine KMTs and JmiC domain-containinlz KDMs balance the osteogenic and adipogenic differentiation of MSCs.
基金supported by National Institute of Dental and Craniofacial Research grant T90DE022734
文摘Mesenchymal stem cell （MSC）-mediated therapy has been shown to be clinically effective in regenerating tissue defects. For improved regenerative therapy, it is critical to isolate homogenous populations of MSCs with high capacity to differentiate into appropriate tissues. The utilization of stem cell surface antigens provides a means to identify MSCs from various tissues. However, few surface markers that consistently isolate highly regenerative MSCs have been validated, making it challenging for routine clinical applications and making it all the more imperative to identify reliable surface markers. In this study, we used three surface marker combinations： CD51/CD140a, CD271, and STRO-1/CD146 for the isolation of homogenous populations of dental mesenchymal stem cells （DMSCs） from heterogeneous periodontal ligament cells （PDLCs）. Fluorescence-activated cell sorting analysis revealed that 24% of PDLCs were CD51＋/CD140a＋, 0.8% were CD271＋, and 2.4% were STRO-1＋/CD146＋. Sorted cell populations were further assessed for their multipotent properties by inducing osteogenic and chondrogenic differentiation. All three subsets of isolated DMSCs exhibited differentiation capacity into osteogenic and chondrogenic lineages but with varying degrees. CD271＋ DMSCs demonstrated the greatest osteogenic potential with strong induction of osteogenic markers such as DLX5, RUNX2, and BGLAP. Our study provides evidence that surface marker combinations used in this study are sufficient markers for the isolation of DMSCs from PDLCs. These results provide important insight into using specific surface markers for identifying homogenous populations of DMSCs for their improved utilization in regenerative medicine.
基金the NIH/NIDCR grant R01DE16513(C.Y.W.),NIH/NIDCR K08DE024603(C.H.)the Shapiro family Charitable Funds.The Flow cytometry was performed in the UCLA Flow Cytometry Core Facility that is supported by NIH awards P30CA016042 and 5P30AI028697.
文摘Mesenchymal stem cells(MSCs)derived from human embryonic stem cells(hESCs)have significant potential for cell-mediated bone regeneration.Our recent study revealed that inhibiting the epigenetic regulator EZH2 plays a key role in promoting the mesodermal differentiation of hESCs.In this study,an epigenome-wide analysis of hESCs and MSCs revealed that growth differentiation factor 6(GDF6),which is involved in bone formation,was the most upregulated gene associated with MSCs compared to hESCs.Furthermore,we identified GDF6 as a repressive target of EZH2 and found that ectopic GDF6 selectively promoted hESC differentiation towards the mesodermal lineage and enriched the MSC population.Our results provide molecular insights governing the mesenchymal commitment of hESCs and identify an inducing factor that offers strong promise for the future of regenerative medicine.
文摘Purpose: To establish a new coordinate system using the incisive canal and incisive foramen in cases confirmed to have root resorption in the maxillary incisor region by cone beam computed tomography (CBCT) to investigate the positions of the central and lateral incisor roots and erupting maxillary canine tooth crowns in the horizontal plane. Methods: Nine patients (two males;mean age: 10.5 years old) with suspected incisor root resorption due to erupting maxillary canines on panoramic X-ray images and in whom incisor root resorption was confirmed on CBCT images were evaluated. A control group of 12 patients with a supernumerary tooth on one side (three males;mean age: 8.6 years old) was also examined. X, Y, and Z-axes were defined, and the positions of the centers of the central incisor root (U1) and lateral incisor root (U2) and the canine cusp (U3) were examined, along with alveolar process width and length. Results: In the control group, U1, U2, and U3 were located within a certain range without overlap, while, in the incisor root resorption group, U3 overlapped with U1 and U2 and tended to deviate centrally. U2 tended to be located further posteriorly than U3. The anteroposterior diameter of the alveolar process was 1.2 mm shorter in the incisor root resorption group (p < 0.05). Conclusions: The risk of incisor root resorption accompanying canine eruption can be evaluated early by investigating the canine position on a horizontal plane established on the upper anterior tooth dentition CT images with a coordinate system using the incisive canal and incisive foramen.
文摘The periodontal ligament (PDL) contains oxytalan fibers as well as collagen fibers, which helps it to withstand the mechanical stress to which it is constantly exposed. The oxytalan fibers are produced by PDL fibroblasts. However, the arrangement of PDL fibroblasts and the orientation of oxytalan fibers relative to the fibroblast cell axis have not been investigated under the condition of mechanical stress. We hypothesized that such stress would alter the arrangement and orientation of these cells and their oxytalan fibers. The aim of this study was to evaluate the effects of stretching strain on PDL fibroblasts, focusing on the cellular arrangement and orientation of oxytalan fibers relative to the long cell axis in cell/matrix layers by staining the major component of the fibers, fibrillin-1. The angle between the long cell axis and the oxytalan fibers was approximately 70 degrees under both non-stretching and stretching conditions. Moreover, stretching induced the rearrangement of the cells. This is the first study to demonstrate that stretching induces the rearrangement of the PDL fibroblasts without altering the angle between the long cell axis and the oxytalan fibers. These results may reflect the orientation of oxytalan fibers in the PDL under the condition of mechanical stress.
基金supported by National Institute of Dental and Craniofacial Research grant T90DE022734
文摘Mesenchymal stem cells （MSCs） are a promising tool in regenerative medicine due to their capacity to differentiate into multiple lineages. In addition to MSCs isolated from bone marrow （BMSCs）, adult MSCs are isolated from craniofacial tissues including dental pulp tissues （DPs） using various stem cell surface markers. However, there has been a lack of consensus on a set of surface makers that are reproducibly effective at isolating putative multipotent dental mesenchymal stem cel^s （~M^Cs）. II1 ~his stucly, we used clif^et（~nt combinations of surface markers （CD51/CD140a, CD271, and STRO-1/CD146） to isolate homogeneous populations of DMSCs from heterogeneous dental pulp cells （DPCs） obtained from DP and compared their capacity to undergo multilineage differentiation. Fluorescence-activated cell sorting revealed that 27.3% of DPCs were CD51＋/CD140a＋, 10.6% were CD271＋, and 0.3% were STRO-1＋/CD146＋. Under odontogenic conditions, all three subsets of isolated DMSCs exhibited differentiation capacity into odontogenic lineages. Among these isolated subsets of DMSCs, CD271＋ DMSCs demonstrated the greatest odontogenic potential. While all three combinations of surface markers in this study successfully isolated DMSCs from DPCs, the single CD271 marker presents the most effective stem cell surface marker for identification of DMSCs with high odontogenic potential. Isolated CD271＋ DMSCs could potentially be utilized for future clinical applications in dentistry and regenerative medicine.
