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Sample records for developing tooth germ

  1. Multiphoton microscopy imaging of developing tooth germs.

    PubMed

    Pan, Pei-Yu; Chen, Rung-Shu; Ting, Chih-Liang; Chen, Wei-Liang; Dong, Chen-Yuan; Chen, Min-Huey

    2014-01-01

    Traditionally, tooth germ is observed by histological investigation with hematoxylin and eosin stain and information may loss during the process. The purpose of this study is to use multiphoton laser fluorescence microscopy to observe the developing tooth germs of mice for building up the database of the images of tooth germs and compare with those from conventional histological analysis. Tooth germs were isolated from embryonic and newborn mice with age of Embryonic Day 14.5 and Postnatal Days 1, 3, 5, and 7. Comparison of the images of tooth germ sections in multiphoton microscopy with the images of histology was performed for investigating the molar tooth germs. It was found that various signals arose from different structures of tooth germs. Pre-dentin and dentin have strong second-harmonic generation signals, while ameloblasts and enamel tissues were shown with strong autofluorescence signals. In this study, a novel multiphoton microscopy database of images from developing tooth germs in mice was set up. We confirmed that multiphoton laser microscopy is a powerful tool for investigating the development of tooth germ and is worthy for further application in the study of tooth regeneration. Copyright © 2012. Published by Elsevier B.V.

  2. Expression of DPP6 in Meckel's cartilage and tooth germs during mouse facial development.

    PubMed

    Du, J; Fan, Z; Ma, X; Wu, Y; Liu, S; Gao, Y; Shen, Y; Fan, M; Wang, S

    2014-01-01

    Dipeptidyl peptidase-like protein 6 (DPP6), a member of the dipeptidyl aminopeptidase family, plays distinct roles in brain development, but its expression in embryonic Meckel's cartilage and tooth germs development is unknown. We analyzed the expression pattern of DPP6 in Meckel's cartilage and tooth germs development using in situ hybridization. DPP6 was detected in different patterns in Meckel's cartilage and tooth germs during mouse facial development from 11.5 to 13.5 days post-coitus (dpc) embryos. The expression pattern of DPP6 suggests that it may be involved in mandible and tooth development.

  3. Morphometric approach to pulp fibroblast development in tooth germ.

    PubMed

    Căruntu, Irina-Draga; Săvinescu, Sergiu Daniel; Amălinei, Cornelia

    2014-01-01

    This paper builds a morphometric framework for the analysis of dental pulp fibroblast evolution during tooth development. We investigated 15 tooth germs (cases) organized, by histological criteria, in three groups corresponding to cap, early bell, and late bell stages, respectively. Each group comprised five cases. The morphometric description used the following parameters: area (A), perimeter (P)--automatically extracted by a color segmentation technique, and form factor (FF)--calculated as 4πA/P (2). The designed framework operated at inter- and intragroup levels. The intergroup analysis quantified the differences between groups, in the sense of a relative distance (RD) adequately defined by mean-value scaling. We showed that the stage of early bell is approximately 5 times closer to late bell than to cap. The quantification procedure required concomitant information about A, P parameters (as P versus A dependences, or FF values), whereas the procedure failed for A or P separately used. The intragroup analysis quantified the similarity of the cases belonging to the same stage. We proved that, unlike the intergroup tests, the individual exploitation of all three descriptors A, P, and FF is effective, yielding highly compatible results. Within any group, most cases presented RDs less than 10% from the group mean value, regardless of the descriptor type.

  4. In vitro three-dimensional development of mouse molar tooth germs in a rotary cell culture system.

    PubMed

    Sun, Liang; Yang, Chao; Ge, Yaneng; Yu, Mei; Chen, Guoqing; Guo, Weihua; Tian, Weidong

    2014-05-01

    In vitro tooth germ cultivation is an effective method to explore the mechanism of odontogenesis. The three-dimensional rotary cell culture system (RCCS) is typically used to culture simulated organs such as cartilage, skin, and bone. In this study, we established an in vitro tooth germ culture model using RCCS to investigate whether RCCS could provide an appropriate environment for tooth germ development in vitro. Mandibular first molar tooth germs from 1-day post-natal mice were cultured in RCCS for 3, 6, and 9 days. Tooth germ development was monitored via histology (hematoxylin & eosin staining), stereoscopic microscopy, and quantitative real-time PCR (RT-PCR). Tooth germs cultured in RCCS maintained their typical spatial shape. Blood vessels were maintained on the dental follicle surface surrounding the crown. After cultivation, thick layers of dentin and enamel were secreted. Compared with tooth germs grown in jaw, the tooth germs grown in RCCS exhibited no significant difference in DMP1 or FGF10 expression at all time points. Use of RCCS enhanced the development of tooth germs and allowed the tooth germs to maintain their spatial morphology. These results indicate that RCCS may be an effective culture system to investigate the mechanism of tooth development. © 2013 BSPD, IAPD and John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  5. Immunohistochemical examination for the distribution of podoplanin-expressing cells in developing mouse molar tooth germs.

    PubMed

    Imaizumi, Yuri; Amano, Ikuko; Tsuruga, Eichi; Kojima, Hiroshi; Sawa, Yoshihiko

    2010-10-27

    We recently reported the expression of podoplanin in the apical bud of adult mouse incisal tooth. This study was aimed to investigate the distribution of podoplanin-expressing cells in mouse tooth germs at several developing stages. At the bud stage podoplanin was expressed in oral mucous epithelia and in a tooth bud. At the cap stage podoplanin was expressed on inner and outer enamel epithelia but not in mesenchymal cells expressing the neural crest stem cell marker nestin. At the early bell stage nestin and podoplanin were expressed in cervical loop and odontoblasts. At the root formation stage both nestin and podoplanin were weakly expressed in odontoblasts generating radicular dentin. Podoplanin expression was also found in the Hertwig epithelial sheath. These results suggest that epithelial cells of developing tooth germ acquire the ability to express nestin, and that tooth germ epithelial cells maintain the ability to express podoplanin in oral mucous epithelia. The expression of podoplanin in odontoblasts was induced as tooth germ development advanced, but was suppressed with the completion of the primary dentin, suggesting that podoplanin may be involved in the cell growth of odontoblasts. Nestin may function as an intermediate filament that binds podoplanin in odontoblasts.

  6. Multiple functional involvement of thymosin beta-4 in tooth germ development.

    PubMed

    Ookuma, Yukiko F; Kiyoshima, Tamotsu; Kobayashi, Ieyoshi; Nagata, Kengo; Wada, Hiroko; Fujiwara, Hiroaki; Yamaza, Haruyoshi; Nonaka, Kazuaki; Sakai, Hidetaka

    2013-02-01

    Thymosin beta-4 (Tβ4) is known to be ubiquitously involved in the actin monomer sequestering on the cytoskeleton. Our previous study showed specific temporal and special in situ expression pattern of Tβ4 mRNA in dental epithelial and mesenchymal cells in the developing tooth germ of the mouse lower first molar. In this study, we examined the functional implications of Tβ4 in the developmental course of the mouse lower first molar. An inhibition assay using Tβ4 antisense sulfur-substituted oligodeoxynucleotide (AS S-ODN) in cultured embryonic day 11.0 (E11.0) mandibles showed a significant growth inhibition of the tooth germ. However, no growth arrest of the cultured E15.0 tooth germ was observed by using Tβ4 AS S-ODN. The Tβ4 knockdown led to significantly decreased expression levels of type II/III runt-related transcription factor 2 (Runx2) and nucleolin (Ncl) in the cultured E11.0 mandibles. Since our previous studies proved that the inhibition of type II/III Runx2 and Ncl translations resulted in the developmental arrest of the tooth germ in the cultured E11.0 mandible, Tβ4 appears to play roles in tooth germ development via the regulation of the type II/III Runx2 and Ncl expressions. Tβ4 knockdown also resulted in decreased secretion of matrix metalloproteinase (Mmp)-2, a reduced cell motility activity and upregulation of E-cadherin in dental epithelial mDE6 cells. These results suggest that Tβ4 plays multiple functional roles in odontogenic epithelial cells in the early stages of tooth germ development by regulating the expression of odontogenesis-related genes.

  7. Expression of DCC in differentiating ameloblasts from developing tooth germs in rats.

    PubMed

    Kim, H J; Jeon, S K; Kang, J H; Kim, M S; Ko, H M; Jung, J Y; Koh, J T; Kim, W J; Lee, E J; Lim, H P; Kim, S H

    2009-06-01

    This study examined the expression pattern of the Deleted-in-colorectal-carcinoma (DCC) gene in developing rat tooth germs. Rat pups at 4, 7 and 10 d postpartum were used in this study. Reverse transcription-polymerase chain reaction (RT-PCR) and immunofluorescent localization were used to determine the level of DCC expression during tooth development. There was more than 2-fold higher level of DCC mRNA in the rat 2nd maxillary molar tooth germs on 10 d postpartum, which was the root stage, than in the rat 3rd maxillary molar tooth germ, which was at the cap/early bell development stage. In addition, the levels of DCC mRNA in the 2nd maxillary molar germs at 4, 7 and 10 d postpartum increased gradually according to tooth development. Interestingly, immunoreactivity against DCC was specifically detected in the differentiating ameloblasts. DCC was observed in the lateral and apical sides of the newly differentiating and secretory stage ameloblasts. Afterwards, DCC was localized only in the apical side of the maturation stage ameloblasts, not in the lateral side. DCC is expressed in the differentiating ameloblasts, which suggests that this molecule plays a crucial role in amelogenesis.

  8. [Beta -transduction repeat containing protein expressed in tooth germs and ameloblast and odontoblast of different stage of tooth development].

    PubMed

    Shen, Yong-Dai; Tian, Wei-Dong; Liu, Lei; He, Yong-Houg; Tang, Wei; Zheng, Xiaohui

    2007-04-01

    The Sonic hedgehog signalling peptide has been demonstrated to play important roles in the growth and patterning of the tooth development. This study aims on whether the antagonist beta-transduction repeat containing protein of Sonic hedgehog signal transduction expressed in tooth germs ameloblast and odontoblast or not. The mouse embryo heads of different developmental stages of E10.5, E13.5, E14.5, E16.5, E18.5 and P0, P3, P6 after birth were acquired fixed with 4% paraformaldehyde for 48 hours, embeded with Paraffin and examined using LsAB (labelled streptavidin-biotin) method to observe the beta-TrCP expression pattern in tooth germs, ameloblast and odontoblast. It was demonstrated that beta-TrCP expressed in oral epithelium, tooth bud, mesenchymal cell cytoplasm of ameloblast and odontoblast of different stage of tooth development. beta-TrCP expressed from early stage to later stage of murine tooth development. And these findings provide the evidence of antagonist regulatory pathways for shh in teeth development.

  9. The slice culture method for following development of tooth germs in explant culture.

    PubMed

    Alfaqeeh, Sarah A; Tucker, Abigail S

    2013-11-13

    Explant culture allows manipulation of developing organs at specific time points and is therefore an important method for the developmental biologist. For many organs it is difficult to access developing tissue to allow monitoring during ex vivo culture. The slice culture method allows access to tissue so that morphogenetic movements can be followed and specific cell populations can be targeted for manipulation or lineage tracing. In this paper we describe a method of slice culture that has been very successful for culture of tooth germs in a range of species. The method provides excellent access to the tooth germs, which develop at a similar rate to that observed in vivo, surrounded by the other jaw tissues. This allows tissue interactions between the tooth and surrounding tissue to be monitored. Although this paper concentrates on tooth germs, the same protocol can be applied to follow development of a number of other organs, such as salivary glands, Meckel's cartilage, nasal glands, tongue, and ear.

  10. Expression patterns of genes critical for BMP signaling pathway in developing human primary tooth germs.

    PubMed

    Dong, Xiuqing; Shen, Bin; Ruan, Ningsheng; Guan, Zhen; Zhang, Yanding; Chen, YiPing; Hu, Xuefeng

    2014-12-01

    The developing murine tooth has been used as an excellent model system to study the molecular mechanism of organ development and regeneration. While the expression patterns of numerous regulatory genes have been examined and their roles have begun to be revealed in the developing murine tooth, little is known about gene expression and function in human tooth development. In order to unveil the molecular mechanisms that regulate human tooth morphogenesis, we examined the expression patterns of the major BMP signaling pathway molecules in the developing human tooth germ at the cap and bell stages by in situ hybridization, immunohistochemistry, and real-time RT-PCR. Expression of BMP ligands and antagonist, including BMP2, BMP3, BMP4, BMP7, and NOOGGIN, exhibited uniform patterns in the tooth germs of incisor and molar at the cap and bell stages with stronger expression in the inner dental epithelium than that in the dental mesenchyme. Both type I and type II BMP receptors were present in widespread expression pattern in the whole-enamel organ and the dental mesenchyme with the strongest expression in inner dental epithelium at the cap and bell stages. SMAD4 and SMAD1/5/8 showed an expression pattern similar to that of BMP ligands with more intensive signals in the inner dental epithelium. Despite some unique and distinct patterns as compared to the mouse, the intensive expression of BMP signaling pathway molecules in the developing human tooth strongly suggests conserved functions of BMP signaling during human odontogenesis, such as in mediating tissue interactions and regulating differentiation and organization of odontogenic tissues. Our results provide an important set of documents for studying molecular regulatory mechanisms underlying tooth development and regeneration in humans.

  11. Vascular endothelial growth factor and nitric oxide synthase expression in human tooth germ development.

    PubMed

    Mastrangelo, F; Sberna, M T; Tettamanti, L; Cantatore, G; Tagliabue, A; Gherlone, E

    2016-01-01

    Vascular Endothelia Growth Factor (VEGF) and Nitric Oxide Synthase (NOS) expression, were evaluated in human tooth germs at two different stages of embryogenesis, to clarify the role of angiogenesis during tooth tissue differentiation and growth. Seventy-two third molar germ specimens were selected during oral surgery. Thirty-six were in the early stage and 36 in the later stage of tooth development. The samples were evaluated with Semi-quantitative Reverse Transcription-Polymerase chain Reaction analyses (RT-PcR), Western blot analysis (WB) and immunohistochemical analysis. Western blot and immunohistochemical analysis showed a VEGF and NOS 1-2-3 positive reaction in all samples analysed. VEGF high positive decrease reaction was observed in stellate reticulum cells, ameloblast and odontoblast clusters in early stage compared to later stage of tooth germ development. Comparable VEGF expression was observed in endothelial cells of early and advanced stage growth. NOS1 and NOS3 expressions showed a high increased value in stellate reticulum cells, and ameloblast and odontoblast clusters in advanced stage compared to early stage of development. The absence or only moderate positive reaction of NOS2 was detected in all the different tissues. Positive NOS2 expression showed in advanced stage of tissue development compared to early stage. The action of VEGF and NOS molecules are important mediators of angiogenesis during dental tissue development. VEGF high positive expression in stellate reticulum cells in the early stage of tooth development compared to the later stage and the other cell types, suggests a critical role of the stellate reticulum during dental embryo-morphogenesis.

  12. Regulation of CCN2 gene expression and possible roles in developing tooth germs.

    PubMed

    Kanyama, Manabu; Shimo, Tsuyoshi; Sugito, Hiroki; Nagayama, Motohiko; Kuboki, Takuo; Pacifici, Maurizio; Koyama, Eiki

    2013-11-01

    CCN proteins are extracellular and cell-associated molecules involved in several developmental processes, but their expression patterns and regulation in tooth development remain unclear. Here we first determined the expression patterns of CCN genes in mouse tooth germs. We found that at early stages CCN2 was detected in dental lamina, dental mesenchyme, and primary enamel knot, while other CCN family members were expressed broadly. By the bell stage, all members were expressed in differentiating odontoblasts and ameloblasts, but CCN1 and CCN2 transcripts were conspicuous in differentiating osteoblasts in dental follicle. Next, we asked what signalling molecules regulate CCN2 expression and what roles CCN2 may have. We found that upon surgical removal of dental epithelium CCN2 was not longer expressed in dental mesenchyme in cultured bud stage germs. Implantation of beads pre-coated with BMPs and FGFs onto E12-13 mandibular explants induced CCN2 expression in dental mesenchyme. There was a dose-dependent effect of BMP-4 on CCN2 induction; a concentration of 100 ng/μl was able to induce strong CCN2 expression while a minimum concentration of 25 ng/μl was needed to elicit appreciable expression. Importantly, Noggin treatment inhibited endogenous and BMP-induced CCN2 expression, verifying that CCN2 expression in developing tooth germs requires BMP signalling. Lastly, we found that rCCN2 stimulated proliferation in dental mesenchyme in a dose-dependent manner. Together, the data indicate that expression of CCN genes is spatio-temporally regulated in developing tooth germs. CCN2 expression appears to depend on epithelial and mesenchymal-derived signalling factors, and CCN2 can elicit strong proliferation in dental mesenchyme. Copyright © 2013 Elsevier Ltd. All rights reserved.

  13. Immunolocalization of heat shock protein 27 in developing jaw bones and tooth germs of human fetuses.

    PubMed

    Leonardi, R; Barbato, E; Paganelli, C; Lo Muzio, L

    2004-12-01

    27 kDa Heat shock protein (Hsp27), which is also identified as p29 estrogen-receptor associated protein, plays a crucial role in specific growth stages. It also seems to be involved in the balance between differentiation and apoptosis. To determine whether Hsp27 is involved during craniofacial development and odontogenesis, its expression was studied through immunohistochemistry of developing jaw bone as well as the odontogenesis of heads from human fetuses. Formalin-fixed paraffin-embedded specimens of 7 human fetuses (3 female, 4 male), obtained from miscarriages occurring between the 9th and 16th weeks of pregnancy, were examined by using a monoclonal antibody against Hsp27. Staining intensity (weak, +; moderate, ++; strong, +++) was evaluated semiquantitatively. The sample slice was cut through a coronal plane, which included eyes, nasal cavities, tongue, and primitive dental lamina with tooth germs. A transient and spatially restricted expression of Hsp27 in developing human jaw bones and teeth was observed. Osteoblasts around the uncalcified bone matrix showed Hsp27 immunoreaction products (+++), whereas osteocytes were not immunolabeled. In mandibular condyle, immunolabeling was restricted to hypertrophic chondrocytes (++). In developing tooth germs, Hsp27 immunostaining was detected throughout the bud (+++). At the early cap stage, a strong immunolabeling for Hsp27 was seen in the dental lamina (+++), and a moderate staining was seen in the outer dental epithelium (++). At the late cap stage, Hsp27 expression was detected in the outer dental epithelium (++) as well as in the cells of the future stellate reticulum (++). The spatiotemporal-restricted expression of Hsp27 in craniofacial bones during development suggests that this protein could be involved in the balance between differentiation and apoptosis, by modulating the viability of osteoblasts and chondrocytes. The specific regional and temporal expression patterns of Hsp27 during tooth development

  14. Possible involvement of melatonin in tooth development: expression of melatonin 1a receptor in human and mouse tooth germs.

    PubMed

    Kumasaka, Shuku; Shimozuma, Masashi; Kawamoto, Tadafumi; Mishima, Kenji; Tokuyama, Reiko; Kamiya, Yoko; Davaadorj, Purevsuren; Saito, Ichiro; Satomura, Kazuhito

    2010-05-01

    Melatonin is known to regulate a variety of physiological processes including control of circadian rhythms, regulation of seasonal reproductive function, regulation of body temperature, free radical scavenging, and so forth. Accumulating evidence from in vitro and in vivo experiments has also suggested that melatonin may have an influence on skeletal growth and bone formation. However, little is known about the effects of melatonin on tooth development and growth, which thus remain to be elucidated. This study was performed to examine the possibility that melatonin might exert its influence on tooth development as well as skeletal growth. Immunohistochemical analysis revealed that melatonin 1a receptor (Mel1aR) was expressed in secretory ameloblasts, the cells of the stratum intermedium and stellate reticulum, external dental epithelial cells, odontoblasts, and dental sac cells. Reverse transcription-polymerase chain reaction and Western blot analysis showed that HAT-7, a rat dental epithelial cell line, expressed Mel1aR and its expression levels increased after the cells reached confluence. These results strongly suggest that melatonin may play a physiological role in tooth development/growth by regulating the cellular function of odontogenic cells in tooth germs.

  15. Vascular endothelial growth factor behavior in different stages of tooth germ development.

    PubMed

    Mastrangelo, Filiberto; Sberna, Maria T; Vinci, Raffaele; Iaderosa, Giovanni; Tettamanti, Lucia; Cantatore, Giuseppe; Tagliabue, Angelo; Gherlone, Enrico F

    2016-08-01

    Scientific studies show a possible influence of intercellular and intracellular proteins (VEGF) on the development of physiological and pathological tissue. VEGF, a key regulator of angiogenesis, it would seem essential to take action during the embryonic development of the dental germ. The purpose of the study is to investigate the importance of the enzymatic activity of VEGF through protein quantification at different stages of tooth germ development. The quantification of VEGF protein was performed by 3 different laboratory tests: Western-blot analysis, semi-quantitative reverse transcriptase-polymerase chain reaction analysis (RT-PCR) and finally immunohistochemical analysis. Cell cultures of tooth tissue examined are: endothelial cells, stellate reticulum cells, odontoblasts and ameoblast. The VEGF peptide seems to induce an intense cell proliferation, not concomitant with differentiation towards the endothelial line. The expression of VEGF in the inner enamel epithelium (ameloblasts) would seem to depend on the stage of differentiation, leading us to deduce that VEGF and its respective receptor are expressed in dental germ and that induce alterations not only on the vascularization, but also on the inner epithelium activation and then on dental enamel development, respectively on cap and bell stages of embryogenesis. In our survey, the positive expression of VEGF in all the samples examined, might suggest a fundamental role of angiogenic gene proteins during all stages of embryonic tooth development. It is also characteristic the behavior of stellate reticulum cells, with a significant reduction in VEGF action between early and late stage, which could suggest a possible role of stellate reticulum cells, which would be able to promote and maintain an adequate energy supply to the tissues during early and late stages of differentiation and proliferation.

  16. Functional tooth restoration utilising split germs through re-regionalisation of the tooth-forming field

    PubMed Central

    Yamamoto, Naomi; Oshima, Masamitsu; Tanaka, Chie; Ogawa, Miho; Nakajima, Kei; Ishida, Kentaro; Moriyama, Keiji; Tsuji, Takashi

    2015-01-01

    The tooth is an ectodermal organ that arises from a tooth germ under the regulation of reciprocal epithelial-mesenchymal interactions. Tooth morphogenesis occurs in the tooth-forming field as a result of reaction-diffusion waves of specific gene expression patterns. Here, we developed a novel mechanical ligation method for splitting tooth germs to artificially regulate the molecules that control tooth morphology. The split tooth germs successfully developed into multiple correct teeth through the re-regionalisation of the tooth-forming field, which is regulated by reaction-diffusion waves in response to mechanical force. Furthermore, split teeth erupted into the oral cavity and restored physiological tooth function, including mastication, periodontal ligament function and responsiveness to noxious stimuli. Thus, this study presents a novel tooth regenerative technology based on split tooth germs and the re-regionalisation of the tooth-forming field by artificial mechanical force. PMID:26673152

  17. Functional tooth restoration utilising split germs through re-regionalisation of the tooth-forming field.

    PubMed

    Yamamoto, Naomi; Oshima, Masamitsu; Tanaka, Chie; Ogawa, Miho; Nakajima, Kei; Ishida, Kentaro; Moriyama, Keiji; Tsuji, Takashi

    2015-12-17

    The tooth is an ectodermal organ that arises from a tooth germ under the regulation of reciprocal epithelial-mesenchymal interactions. Tooth morphogenesis occurs in the tooth-forming field as a result of reaction-diffusion waves of specific gene expression patterns. Here, we developed a novel mechanical ligation method for splitting tooth germs to artificially regulate the molecules that control tooth morphology. The split tooth germs successfully developed into multiple correct teeth through the re-regionalisation of the tooth-forming field, which is regulated by reaction-diffusion waves in response to mechanical force. Furthermore, split teeth erupted into the oral cavity and restored physiological tooth function, including mastication, periodontal ligament function and responsiveness to noxious stimuli. Thus, this study presents a novel tooth regenerative technology based on split tooth germs and the re-regionalisation of the tooth-forming field by artificial mechanical force.

  18. An in situ hybridization study of Hyaluronan synthase (Has) mRNA in developing mouse molar and incisor tooth germs.

    PubMed

    Morita, Tsuyoshi; Fujikawa, Kaoru; Baba, Otto; Shibata, Shunichi

    2016-05-01

    Hyaluronan (HA) is a major constituent molecule in most extracellular matrices and is synthesized by Hyaluronan synthase (Has). In the present study, we examined expression patterns of Has1, -2, -3 mRNA in developing mouse molar and incisor tooth germs from embryonic day (E) 11.5 to postnatal day (P) 7, focusing on Hertwig's epithelial root sheath (HERS) and the apical bud in particular. Has1 mRNA expression was not detected in all tooth germs examined. Has2 mRNA was expressed in the surrounding mesenchyme from E12.0 to 18.0 in both molar and incisor tooth germs, but disappeared after birth. Meanwhile, Has3 mRNA was exclusively expressed within the enamel organ, especially in the inner enamel epithelium (IEE), stellate reticulum (SR), and stratum intermedium (SI) until the early bell stage at E16.0. Has3 mRNA disappeared as IEE differentiated into differentiating ameloblasts (dABs), but remained in SI until the root developmental stage of the molar tooth germ at P7. Has3 mRNA was also expressed in HERS until P7. In incisors, Has3 mRNA was expressed in the apical bud, especially in the transit-amplifying (TA) cell region from E16.0 to P7, and in the papillary layer (PL) adjacent to the mature enamel. These gene expression patterns suggested that Has3 is the main control factor for prenatal and postnatal HA synthesis of the tooth germ, and may in part regulate crown and root formation of the tooth germ, maintenance of stem cell niches in the apical bud as well as mineral transport in PL. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Quantitative analysis of fluoride-induced hypermineralization of developing enamel in neonatal hamster tooth germs

    NASA Astrophysics Data System (ADS)

    Tros, G. H. J.; Lyaruu, D. M.; Vis, R. D.

    1993-10-01

    A procedure was developed for analysing the effect of fluoride on mineralization in the enamel of neonatal hamster molars during amelogenesis by means of the quantitative determination of the mineral content. In this procedure the distribution of calcium and mineral concentration was determined in sections containing developing tooth enamel mineral embedded in an organic epoxy resin matrix by means of the micro-PIXE technique. This allowed the determination of the calcium content along preselected tracks with a spatial resolution of 2 μm using a microprobe PIXE setup with a 3 MeV proton beam of 10 to 50 pA with a spot size of 2 μm in the track direction. In this procedure the X-ray yield is used as a measure for the calcium content. The thickness of each sample section is determined independently by measuring the energy loss of α-particles from a calibration source upon passing through the sample. The sample is considered as consisting of two bulk materials, allowing the correction for X-ray self-absorption and the calculation of the calcium concentration. The procedure was applied for measuring the distribution of mineral concentration in 2 μm thick sections taken from tooth germs of hamsters administered with NaF. The measurements indicated that a single intraperitoneal administration of 20 mg NaF/kg body weight to 4-to-5-day-old hamsters leads within 24 h to hypermineralization of certain focal enamel surface areas containing cystic lesions under transitional and early secretory ameloblasts. The mineral concentration there is substantially increased due to the fluoride treatment (35%, instead of 5 to 10% as in the controls), indicating that the normal mineralization process has been seriously disturbed. Furthermore it is found that using this technique the mineral concentration peaks at about 70% at the dentine-enamel junction, which is comparable to that reported for human dentine using other techniques.

  20. [Expression patterns of amelogenin and enamelin in developing mouse tooth germs].

    PubMed

    Tian, Hua; Lü, Ping; Zhou, Chun-yan; Gao, Xue-jun

    2012-03-01

    To invesitgate the expression patterns of amelogenin and enamelin in the developing tooth germs. Mandible sections of postnatal day 1, 3, 7 and 14 mouse were prepared, immunohistochemical analysis and reverse transcriptase polymerase chain reaction (RT-PCR) were performed to detect the expression patterns of amelogenin and enamelin in mandibular first molars. Amelogenin was observed in the cytoplasm of secretory ameloblasts and the whole enamel matrix layer. It was also transiently expressed in the odontoblasts of postnatal day 1 molars. Enamelin proteins were observed in the enamel layer deposited by secretory ameloblasts, especially intense beneath the ameloblast process and dentino-enamel junction. The mRNA levels of both amelogenin and enamelin were highest on postnatal day 7 (the ratio to glyceraldehyde phosphate dehydrogenase of amelogenin and enamelin: 0.813 ± 0.085 and 0.799 ± 0.064, respectively, P < 0.05). Amelogenin and enamelin were enamel matrix proteins predominately expressed by secretory ameloblasts. The temporal-spatial expression patterns of amelogenin and enamelin indicate the important roles they played in amelogenesis and biomineralization.

  1. The effect of fluoride on mineralization during tooth germ development in neonatal hamsters

    NASA Astrophysics Data System (ADS)

    Tros, G. H. J.; Lyaruu, D. M.; Vis, R. D.

    1990-04-01

    The effect of fluoride on calcium and phosphorus content (a measure for mineralization) in maxillary first molar tooth germs from neonatal hamsters (4 to 5 days old, 4 to 5 g body weight) was analysed using the proton nuclear microprobe PIXE setup of the Vrije Universiteit. A 3 MeV proton beam of about 500 pA with a spot size of 5 × 20 μm 2 was used to perform scans of about 400 μm, each taking about 20 to 30 minutes. The smaller beam dimension was always tuned parallel to the scan direction. Line scans with a lateral resolution of 5 μm were made across the enamel organ of germs from animals injected with 20 mg NaF/kg body weight 24 h prior to dissection. The control animals were injected with NaCl. Fluoride administration induced the formation of sub-ameloblastic cystic lesions under some (but not all) populations of transitional and secretory ameloblasts, accompanied by hypermineralization (deposition of more mineral than that found in the controls) of the underlying enamel surface. These hypermineralized regions had been shown in earlier studies to contain elevated fluorine content [1,2].

  2. Localization of Beclin1 in mouse developing tooth germs: possible implication of the interrelation between autophagy and apoptosis.

    PubMed

    Yang, Jingwen; Wan, Chunyan; Nie, Shuai; Jian, Shujuan; Sun, Zheyi; Zhang, Lu; Chen, Zhi

    2013-12-01

    Our previous study identified the appearance of autophagy in developing tooth germs, and suggested its possible association with apoptosis in odontogenesis. Beclin1 was recently indicated to play a central role in bridging autophagy and apoptosis, and occupied a key position in the process of development. This study hypothesized that Beclin1 may be involved, and act as the molecular basis of the connection between autophagy and apoptosis in odontogenesis. Immunohistochemical analysis showed the spatiotemporal expression pattern of Beclin1 in odontogenesis from embryonic (E) day 13.5 to postnatal (P) day 5.5. At E stages, Beclin1 was mainly immunolocalized in the cytoplasm of the cells in the enamel organ. Meanwhile, the nucleus localization of Beclin1 was detected in part of the stellate reticulum, outer and inner enamel epithelium, especially at E16.5 and E18.5. At P stages, Beclin1 was detected in the cytoplasm of the odontoblasts, besides the dental epithelium cells. Triple immunofluorescence analysis showed the partial colocalization of Beclin1, autophagic marker LC3, or activated caspase-3 in the E14.5 tooth germs, especially the Beclin1(+)LC3(+)Caspase-3(+) cells in the PEK. Furthermore, western blot analysis revealed that the full-length (60 kDa) and/or cleaved (50, 37, and 35 kDa) Beclin1 in the developing tooth germs. Taken together, our findings indicate that Beclin1 is involved, and might be responsible for the crosstalk between autophagy and apoptosis in mouse odontogenesis.

  3. Distribution pattern of cholinesterase enzymes in human tooth germs.

    PubMed

    Nandasena, T L; Jayawardena, C K; Tilakaratne, W M; Nanayakkara, C D

    2010-08-01

    The two distinct molecular forms of cholinesterase (ChE) are acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). Our previous studies have reported that ChE is involved in tooth development. However, further experiments are needed to understand the precise action of ChE in tooth development. This study aimed to localise types of ChE in human tooth germs, and identify their distribution pattern. ChE were localised in frozen sections of jaws which were prepared from dead fetuses, neonates and stillborns who were free from visible abnormalities by Karnovsky and Root method. AChE was identified in the inner and outer enamel epithelia including the cervical loop region, stratum intermedium and preameloblasts of tooth germs at bell stage. Secretory ameloblasts were free from staining. The bud and cap stages of permanent tooth germs showed AChE activity on the lingual aspect and top surface of the epithelial ingrowths, respectively. BuChE activity was localised in the degenerating dental lamina. Our study reported the first evidence of localisation of ChE in human tooth development and identified the possible molecular form of ChE in tooth germs as AChE. Also, our results have provided strong evidence to speculate the action of AChE is on the cells of enamel organ during tooth development.

  4. Esthetic and endosurgical management of Turner's hypoplasia; a sequlae of trauma to developing tooth germ.

    PubMed

    Bhushan, B A; Garg, S; Sharma, D; Jain, M

    2008-01-01

    Turner's hypoplasia usually manifests as a portion of missing or diminished enamel, generally affecting one or more permanent teeth in the oral cavity. A case report of 8 year old girl who met with trauma at 2 years of age leading to primary incisors being knocked out, reported after 6 years with complaint of pain and discharge in her anterior malformed teeth is discussed in this article. The permanent incisors erupted with dilacerated crown, root malformations and missing enamel. Further, patient developed sinus, lateral root pathology, tooth mobility and malocclusion in relation to affected teeth which were managed by esthetic, functional, endodontic and surgical procedure. Root canal treatment along with palatal contouring and esthetic restoration by light cure composite was performed on the tooth with crown dilaceration and sinus, where as surgical management was considered for the tooth with root malformation.

  5. Sema3A chemorepellant regulates the timing and patterning of dental nerves during development of incisor tooth germ.

    PubMed

    Shrestha, Anjana; Moe, Kyaw; Luukko, Keijo; Taniguchi, Masahiko; Kettunen, Paivi

    2014-07-01

    Semaphorin 3A (Sema3A) axon repellant serves multiple developmental functions. Sema3A mRNAs are expressed in epithelial and mesenchymal components of the developing incisor in a dynamic manner. Here, we investigate the functions of Sema3A during development of incisors using Sema3A-deficient mice. We analyze histomorphogenesis and innervation of mandibular incisors using immunohistochemistry as well as computed tomography and thick tissue confocal imaging. Whereas no apparent disturbances in histomorphogenesis or hard tissue formation of Sema3A (-/-) incisors were observed, nerve fibers were prematurely seen in the presumptive dental mesenchyme of the bud stage Sema3A (-/-) tooth germ. Later, nerves were ectopically present in the Sema3A (-/-) dental papilla mesenchyme during the cap and bell stages, whereas in the Sema3A (+/+) mice the first nerve fibers were seen in the pulp after the onset of dental hard tissue formation. However, no apparent topographic differences in innervation pattern or nerve fasciculation were seen inside the pulp between postnatal and adult Sema3A (+/+) or Sema3A (-/-) incisors. In contrast, an abnormally large number of nerves and arborizations were observed in the Sema3A (-/-) developing dental follicle target field and periodontium and, unlike in the wild-type mice, nerve fibers were abundant in the labial periodontium. Of note, the observed defects appeared to be mostly corrected in the adult incisors. The expressions of Ngf and Gdnf neurotrophins and their receptors were not altered in the Sema3A (-/-) postnatal incisor or trigeminal ganglion, respectively. Thus, Sema3A is an essential, locally produced chemorepellant, which by creating mesenchymal exclusion areas, regulates the timing and patterning of the dental nerves during the development of incisor tooth germ.

  6. Regulation of proliferation in developing human tooth germs by MSX muscle segment homeodomain proteins and cyclin-dependent kinase inhibitor p19(INK4d).

    PubMed

    Kero, Darko; Vukojevic, Katarina; Stazic, Petra; Sundov, Danijela; Brakus, Snjezana Mardesic; Saraga-Babic, Mirna

    2017-09-21

    Before the secretion of hard dental tissues, tooth germs undergo several distinctive stages of development (dental lamina, bud, cap and bell). Every stage is characterized by specific proliferation patterns, which is regulated by various morphogens, growth factors and homeodomain proteins. The role of MSX homeodomain proteins in odontogenesis is rather complex. Expression domains of genes encoding for murine Msx1/2 during development are observed in tissues containing highly proliferative progenitor cells. Arrest of tooth development in Msx knockout mice can be attributed to impaired proliferation of progenitor cells. In Msx1 knockout mice, these progenitor cells start to differentiate prematurely as they strongly express cyclin-dependent kinase inhibitor p19(INK4d). p19(INK4d) induces terminal differentiation of cells by blocking the cell cycle in mitogen-responsive G1 phase. Direct suppression of p19(INK4d) by Msx1 protein is, therefore, important for maintaining proliferation of progenitor cells at levels required for the normal progression of tooth development. In this study, we examined the expression patterns of MSX1, MSX2 and p19(INK4d) in human incisor tooth germs during the bud, cap and early bell stages of development. The distribution of expression domains of p19(INK4d) throughout the investigated period indicates that p19(INK4d) plays active role during human tooth development. Furthermore, comparison of expression domains of p19(INK4d) with those of MSX1, MSX2 and proliferation markers Ki67, Cyclin A2 and pRb, indicates that MSX-mediated regulation of proliferation in human tooth germs might not be executed by the mechanism similar to one described in developing tooth germs of wild-type mouse.

  7. Facioscapulohumeral muscular dystrophy (FSHD) region gene 1 (FRG1) expression and possible function in mouse tooth germ development.

    PubMed

    Hasegawa, Kana; Wada, Hiroko; Nagata, Kengo; Fujiwara, Hiroaki; Wada, Naohisa; Someya, Hirotaka; Mikami, Yurie; Sakai, Hidetaka; Kiyoshima, Tamotsu

    2016-08-01

    Abnormal expression of Facioscapulohumeral muscular dystrophy (FSHD) region gene 1 (FRG1) is involved in the pathogenesis of FSHD. FRG1 is also important for the normal muscular and vascular development. Our previous study showed that FRG1 is one of the highly expressed genes in the mandible on embryonic day 10.5 (E10.5) than on E12.0. In this study, we investigated the temporospatial expression pattern of FRG1 mRNA and protein during the development of the mouse lower first molar, and also evaluated the subcellular localization of the FRG1 protein in mouse dental epithelial (mDE6) cells. The FRG1 expression was identified in the dental epithelial and mesenchymal cells at the initiation and bud stages. It was detected in the inner enamel epithelium at the cap and early bell stages. At the late bell and root formation stages, these signals were detected in ameloblasts and odontoblasts during the formation of enamel and dentin matrices, respectively. The FRG1 protein was localized in the cytoplasm in the mouse tooth germ in vivo, while FRG1 was detected predominantly in the nucleus and faintly in the cytoplasm in mDE6 cells in vitro. In mDE6 cells treated with bone morphogenetic protein 4 (BMP4), the protein expression of FRG1 increased in cytoplasm, suggesting that FRG1 may translocate to the cytoplasm. These findings suggest that FRG1 is involved in the morphogenesis of the tooth germ, as well as in the formation of enamel and dentin matrices and that FRG1 may play a role in the odontogenesis in the mouse following BMP4 stimulation.

  8. Analysis of expression patterns of IGF-1, caspase-3 and HSP-70 in developing human tooth germs.

    PubMed

    Kero, Darko; Kalibovic Govorko, Danijela; Medvedec Mikic, Ivana; Vukojevic, Katarina; Cigic, Livia; Saraga-Babic, Mirna

    2015-10-01

    To analyze expression patterns of IGF-1, caspase-3 and HSP-70 in human incisor and canine tooth germs during the late bud, cap and bell stages of odontogenesis. Head areas or parts of jaw containing teeth from 10 human fetuses aged between 9th and 20th developmental weeks were immunohistochemically analyzed using IGF-1, active caspase-3 and HSP-70 markers. Semi-quantitative analysis of each marker's expression pattern was also performed. During the analyzed period, IGF-1 and HSP-70 were mostly expressed in enamel organ. As development progressed, expression of IGF-1 and HSP-70 became more confined to differentiating tissues in the future cusp tip area, as well as in highly proliferating cervical loops. Few apoptotic bodies highly positive to active caspase-3 were observed in enamel organ and dental papilla from the cap stage onward. However, both enamel epithelia moderately expressed active caspase-3 throughout the investigated period. Expression patterns of IGF-1, active caspase-3 and HSP-70 imply importance of these factors for early human tooth development. IGF-1 and HSP-70 have versatile functions in control of proliferation, differentiation and anti-apoptotic protection of epithelial parts of human enamel organ. Active caspase-3 is partially involved in formation and apoptotic removal of primary enamel knot, although present findings might reflect its ability to perform other non-death functions such as differentiation of hard dental tissues secreting cells and guidance of ingrowth of proliferating cervical loops. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Accelerated bone formation and increased osteoblast number contribute to the abnormal tooth germ development in parathyroid hormone-related protein knockout mice.

    PubMed

    Kitahara, Y; Suda, N; Terashima, T; Baba, O; Mekaapiruk, K; Hammond, V E; Takano, Y; Ohyama, K

    2004-11-01

    Our previous study showed that tooth germs at late embryonic stage [later than embryonic day 17.5 (E17.5)] and neonatal homozygous parathyroid hormone-related protein (PTHrP)-knockout mice are compressed or penetrated by the surrounding alveolar bone tissue. In vivo and in vitro studies have shown that the development of the tooth germ proper is not disturbed, but insufficient alveolar bone resorption, due to the decreased number and hypofunction of osteoclasts, is the main cause of this abnormality. In addition to the insufficient alveolar bone resorption, progressive bone formation toward tooth germs was observed in homozygous mice, suggesting that accelerated bone formation also contributes to this abnormality. To further investigate this, homozygous mice at E14.0 and E15.5, when alveolar bone is forming, were used for histochemical and bone histomorphometric analyses. In contrast to the late embryonic stage, the alveolar bone did not yet compress developing tooth germs in homozygous mice on E14.0, but a larger amount of bone tissue was seen compared to wild-type littermates. Histomorphometric analysis of bone at E14.0 revealed that the osteoblast numbers and surfaces in the mandibles and in the bone collar of femora of homozygous mice were significantly higher than those of wild-type mice. However, unlike our previous study showing the osteoclast surface on E18.5 in homozygous mice to be significantly lower than that of wild-type mice, this study at E14.0 showed no significant difference between the two genotypes. To evaluate the amount of calcification around tooth germs, 3D images of mandibles were reconstructed from the calcein-labeled sections of the wild-type and mutant mice. Labeling was performed at E14.0, and the mice were sacrificed 1 h after the calcein injection to minimize the effect of bone resorption. Comparison of the 3D images revealed that the labeled surface was larger around developing tooth germs in homozygous mouse than in wild-type mouse

  10. Micro-PIGE determination of fluorine distribution in developing hamster tooth germs

    SciTech Connect

    Lyaruu, D.M.; Lenglet, W.J.; Woeltgens, J.H.B.; Bronckers, A.L.

    1989-05-01

    A micro-PIGE (Proton-Induced gamma-ray Emission) technique based on the delayed 5/2+----1/2+ nuclear transition of fluorine (E gamma = 197 keV, t1/2 = 87 ns) emitted after /sup 19/F(p,p', gamma)/sup 19/F reaction was used to detect and study the distribution of fluorine in the developing enamel organ during pre-eruptive stages, i.e., the transitional to early maturation stages of enamel formation in neonatal hamsters administered a single IP dose of sodium fluoride (20 mg NaF/kg body weight). The aforementioned nuclear reaction is unique for fluorine, and therefore detection of gamma-rays emanating from this reaction in a biological specimen implies a positive identification of fluorine at that particular site. Calcium and phosphorus X-rays were also recorded and used as parameters for assessment of the relationship between the degree of mineralization and fluoride incorporation into the enamel organ. The highest fluorine concentration in the enamel organ was recorded in the dentin near the dentin-enamel junction (DEJ). In the enamel, the highest concentration of fluorine was found to be associated with the more mature areas of the enamel near the DEJ, but gradually decreased in the direction of the enamel surface. Fluorine was not detected in the control germs. These results suggest that administration of fluoride in high doses during the pre-eruptive stages of enamel formation leads to incorporation of the ion into the forming dentin and enamel mineral, and that the enamel matrix does not seem to bind fluoride avidly.

  11. Micro-PIGE determination of fluorine distribution in developing hamster tooth germs.

    PubMed

    Lyaruu, D M; Lenglet, W J; Wöltgens, J H; Bronckers, A L

    1989-05-01

    A micro-PIGE (Proton-Induced gamma-ray Emission) technique based on the delayed 5/2+----1/2+ nuclear transition of fluorine (E gamma = 197 keV, t1/2 = 87 ns) emitted after 19F(p,p', gamma)19F reaction was used to detect and study the distribution of fluorine in the developing enamel organ during pre-eruptive stages, i.e., the transitional to early maturation stages of enamel formation in neonatal hamsters administered a single IP dose of sodium fluoride (20 mg NaF/kg body weight). The aforementioned nuclear reaction is unique for fluorine, and therefore detection of gamma-rays emanating from this reaction in a biological specimen implies a positive identification of fluorine at that particular site. Calcium and phosphorus X-rays were also recorded and used as parameters for assessment of the relationship between the degree of mineralization and fluoride incorporation into the enamel organ. The highest fluorine concentration in the enamel organ was recorded in the dentin near the dentin-enamel junction (DEJ). In the enamel, the highest concentration of fluorine was found to be associated with the more mature areas of the enamel near the DEJ, but gradually decreased in the direction of the enamel surface. Fluorine was not detected in the control germs. These results suggest that administration of fluoride in high doses during the pre-eruptive stages of enamel formation leads to incorporation of the ion into the forming dentin and enamel mineral, and that the enamel matrix does not seem to bind fluoride avidly.

  12. Fate of fluoride-induced subameloblastic cysts in developing hamster molar tooth germs.

    PubMed

    Lyaruu, D M; Alberga, J M R; Kwee, N C H; Bervoets, T J M; Bronckers, A L J J; DenBesten, P K

    2011-03-01

    White opacities and pits are developmental defects in enamel caused by high intake of fluoride (F) during amelogenesis. We tested the hypothesis that these enamel pits develop at locations where F induces the formation of sub-ameloblastic cysts. We followed the fate of these cysts during molar development over time. Mandibles from hamster pups injected with 20mg NaF/kg at postnatal day 4 were excised from 1h after injection till shortly after tooth eruption, 8 days later. Tissues were histologically processed and cysts located and measured. Cysts were formed at early secretory stage and transitional stage of amelogenesis and detected as early 1h after injection. The number of cysts increased from 1 to almost 4 per molar during the first 16h post-injection. The size of the cysts was about the same, i.e., 0.46±0.29×10(6)μm(3) at 2h and 0.50±0.35×10(7)μm(3) at 16h post-injection. By detachment of the ameloblasts the forming enamel surface below the cyst was cell-free for the first 16h post-injection. With time new ameloblasts repopulated and covered the enamel surface in the cystic area. Three days after injection all cysts had disappeared and the integrity of the ameloblastic layer restored. After eruption, white opaque areas with intact enamel surface were found occlusally at similar anatomical locations as late secretory stage cysts were seen pre-eruptively. We conclude that at this moderate F dose, the opaque sub-surface defects with intact surface enamel (white spots) are the consequence of the fluoride-induced cystic lesions formed earlier under the late secretory-transitional stage ameloblasts. Copyright © 2010 Elsevier Ltd. All rights reserved.

  13. FATE OF FLUORIDE-INDUCED SUBAMELOBLASTIC CYSTS IN DEVELOPING HAMSTER MOLAR TOOTH GERMS

    PubMed Central

    Lyaruu, DM; Alberga, JMR; Kwee, NCH; Bervoets, TJM; Bronckers, ALJJ; DenBesten, PK

    2016-01-01

    White opacities and pits are developmental defects in enamel caused by high intake of fluoride (F) during amelogenesis. We tested the hypothesis that these enamel pits develop at locations where F induces the formation of sub-ameloblastic cysts. We followed the fate of these cysts during molar development over time. Mandibles from hamster pups injected with 20 mg NaF/kg at postnatal day 4 were excised from 1 h after injection till shortly after tooth eruption, 8 days later. Tissues were histologically processed and cysts located and measured. Cysts were formed at early secretory stage and transitional stage of amelogenesis and detected as early 1 h after injection. The number of cysts increased from 1 to almost 4 per molar during the first 16 h post-injection. The size of the cysts was about the same, i.e., 0.46±0.29 ×106 μm3 at 2hr and 0.50±0.35×106 μm3 at 16 h post-injection. By detachment of the ameloblasts the forming enamel surface below the cyst was cell-free the first 16 h post-injection. With time new ameloblasts repopulated and covered the enamel surface in the cystic area. Three days after injection all cysts had disappeared and the integrity of the ameloblastic layer restored. After eruption, white opaque areas with intact enamel surface were found occlusally at similar anatomical locations as late secretory stage cysts were seen pre-eruptively. We conclude that at this moderate F dose, the opaque sub-surface defects with intact surface enamel (white spots) are the consequence of the fluoride-induced cystic lesions formed earlier under the late secretory–transitional stage ameloblasts. PMID:21277565

  14. No developmental failure of cultured tooth germs from osteopetrotic (op/op) mice.

    PubMed

    Ida-Yonemochi, Hiroko; Saku, Takashi

    2002-07-01

    Incisor tooth germs of osteopetrotic (op/op) mice are known to fail to erupt, but form odontomas in their root apices instead, due to invasion of alveolar bone trabeculae into the tooth germs. The purpose of this study is to determine if the tooth developmental failures in op/op mice are intrinsic or secondarily arise as a result of the defective bone metabolism due to lack of macrophage colony-stimulating factor (M-CSF). We isolated mandibular first molar tooth germs from normal and op/op mice and cultured them under conditions with or without bone tissues which had been formed around tooth germs. Tooth germs from normal mice, cultured for a week, showed almost the same developmental features as those of mice with the corresponding age. They were surrounded with dental follicular tissues and were never invaded by bone trabeculae. On the other hand, op/op tooth germs cultured in the presence of bone components were invaded by alveolar bone trabeculae around tooth germs in the same manner as shown in vivo. When cultured without bone, they developed without any interruptions. These findings indicated that op/op tooth germs had potential for normal development and that their abnormal development was a secondary phenomenon caused by lack of bone remodeling in the early phase of odontogenesis.

  15. Organ cultures and kidney-capsule grafting of tooth germs.

    PubMed

    Otsu, Keishi; Fujiwara, Naoki; Harada, Hidemitsu

    2012-01-01

    The study of organogenesis allows investigation of a variety of basic biological processes in the context of the intact organ. The ability to analyze teeth ex vivo during development has emerged as a powerful tool to understand how teeth are constructed and the signaling pathways that regulate these developmental processes. Here, we describe in detail our protocols for organ culture and kidney-capsule grafting of mouse tooth germs. These techniques allow us to reproduce the developmental process of tooth germs and estimate the effect of specific genes ex vivo, as well as are a tool for studies on the mechanisms of normal and abnormal tooth morphogenesis. They may also be applied to studies on other aspects of developmental biology and regenerative medicine.

  16. Immunocytochemical localization of vascular endothelial growth factor and vascular endothelial growth factor receptor-2 of the human deciduous molar tooth germ development in the human fetus.

    PubMed

    Miwa, Yoko; Fujita, Toshiya; Sunohara, Masataka; Sato, Iwao

    2008-01-01

    Vascular endothelial growth factor (VEGF) is a key regulator of blood vessel endothelial development. We used immunohistochemical methods to demonstrate the localization of VEGF and its receptors, showing the specific expression pattern of VEGF and VEGF receptor in the human deciduous tooth from the cap to late bell stages in the human fetus. Immunoreactivity to VEGF and its receptor VEGF receptor-2 (VEGFR-2) was intensely positive in the inner enamel epithelium at the cap stage and ranged from negative to moderately positive in the bell stage. At the late bell stage, VEGF immunoreactivity was mainly positive but weak for VEGFR-2. The intensity of VEGF and VEGFR-2 in odontoblasts increases from cap stage to late bell stage. We postulate that the dissimilar expression of VEGF in inner enamel epithelium, ameloblast and odontoblast during each stage of human tooth development may affect tooth germ formation.

  17. Two-Dimensional Identification of Fetal Tooth Germs.

    PubMed

    Seabra, Mariana; Vaz, Paula; Valente, Francisco; Braga, Ana; Felino, António

    2017-03-01

      To demonstrate the efficiency and applicability of two-dimensional ultrasonography in the identification of tooth germs and in the assessment of potential pathology.   Observational, descriptive, cross-sectional study.   Prenatal Diagnosis Unit of Centro Hospitalar de Vila Nova de Gaia / Espinho-Empresa Pública in Portugal.   A total of 157 white pregnant women (median age, 32 years; range, 14 to 47 years) undergoing routine ultrasound exams.   Description of the fetal tooth germs, as visualized by two-dimensional ultrasonography, including results from prior fetal biometry and detailed screening for malformations.   In the first trimester group, ultrasonography identified 10 tooth germs in the maxilla and 10 tooth germs in the mandible in all fetuses except for one who presented eight maxillary tooth germs. This case was associated with a chromosomal abnormality (trisomy 13) with a bilateral cleft palate. In the second and third trimesters group, ultrasonography identified a larger range of tooth germs: 81.2% of fetuses showed 10 tooth germs in the maxilla and 85.0% of fetuses had 10 tooth germs in the mandible. Hypodontia was more prevalent in the maxilla than in the mandible, which led us to use qualitative two-dimensional ultrasonography to analyze the possible association between hypodontia and other variables such as fetal pathology, markers, head, nuchal, face, and spine.   We recommend using this method as the first exam to evaluate fetal morphology and also to help establish accurate diagnosis of abnormalities in pregnancy.

  18. X-ray micro-analysis of the mineralization patterns in developing enamel in hamster tooth germs exposed to fluoride in vitro during the secretory phase of amelogenesis

    SciTech Connect

    Lyaruu, D.M.; Blijleven, N.; Hoeben-Schornagel, K.; Bronckers, A.L.; Woeltgens, J.H.

    1989-09-01

    The developing enamel from three-day-old hamster first maxillary (M1) molar tooth germs exposed to fluoride (F-) in vitro was analyzed for its mineral content by means of the energy-dispersive x-ray microanalysis technique. The aim of this study was to obtain semi-quantitative data on the F(-)-induced hypermineralization patterns in the enamel and to confirm that the increase in electron density observed in micrographs of F(-)-treated enamel is indeed due to an increase in mineral content in the fluorotic enamel. The tooth germs were explanted during the early stages of secretory amelogenesis and initially cultured for 24 hr in the presence of 10 ppm F- in the culture medium. The germs were then cultured for another 24 hr without F-. In order to compare the ultrastructural results directly with the microprobe data, we used the same specimens for both investigations. The net calcium counts (measurement minus background counts) in the analyses were used as a measure of the mineral content in the enamel. The aprismatic pre-exposure enamel, deposited in vivo before the onset of culture, was the most hypermineralized region in the fluorotic enamel, i.e., it contained the highest amount of calcium measured. The degree of the F(-)-induced hypermineralization gradually decreased (but was not abolished) in the more mature regions of the enamel. The unmineralized enamel matrix secreted during the initial F- treatment in vitro mineralized during the subsequent culture without F-. The calcium content in this enamel layer was in the same order of magnitude as that recorded for the newly deposited enamel in control tooth germs cultured without F-.

  19. Practical whole-tooth restoration utilizing autologous bioengineered tooth germ transplantation in a postnatal canine model

    PubMed Central

    Ono, Mitsuaki; Oshima, Masamitsu; Ogawa, Miho; Sonoyama, Wataru; Hara, Emilio Satoshi; Oida, Yasutaka; Shinkawa, Shigehiko; Nakajima, Ryu; Mine, Atsushi; Hayano, Satoru; Fukumoto, Satoshi; Kasugai, Shohei; Yamaguchi, Akira; Tsuji, Takashi; Kuboki, Takuo

    2017-01-01

    Whole-organ regeneration has great potential for the replacement of dysfunctional organs through the reconstruction of a fully functional bioengineered organ using three-dimensional cell manipulation in vitro. Recently, many basic studies of whole-tooth replacement using three-dimensional cell manipulation have been conducted in a mouse model. Further evidence of the practical application to human medicine is required to demonstrate tooth restoration by reconstructing bioengineered tooth germ using a postnatal large-animal model. Herein, we demonstrate functional tooth restoration through the autologous transplantation of bioengineered tooth germ in a postnatal canine model. The bioengineered tooth, which was reconstructed using permanent tooth germ cells, erupted into the jawbone after autologous transplantation and achieved physiological function equivalent to that of a natural tooth. This study represents a substantial advancement in whole-organ replacement therapy through the transplantation of bioengineered organ germ as a practical model for future clinical regenerative medicine. PMID:28300208

  20. [Dentification ability of inbred strain mice tooth germs homologically transplanted into oral submucosa].

    PubMed

    Li, Heng; Que, Guoying; Zhang, Lei

    2010-05-01

    To establish a suitable environment for the bioengineered teeth in vivo by observing the dentification ability of BALB/C mice tooth germs homologically implanted into the oral submucosa. The first molar tooth germs of BALB/C mice 4 days after birth were transplanted into the oral submucosa of BALB/C male mice, and then recycled for regular histological observation after 1, 2, 3, and 6 week transplantation. The tooth germs in the oral submucosa grew well with continuing developing enamelum and pulpodentinal complex, and the dentinal tubules were clear. The environment of the BALB/C male mice oral submucosa is favorable for the growth of tooth germs in inbred strain BALB/C mice, and it can provide a new environment for the development of bioengineered teeth in vivo.

  1. Distribution of Cathepsin K in Late Stage of Tooth Germ Development and Its Function in Degrading Enamel Matrix Proteins in Mouse.

    PubMed

    Jiang, Tao; Liu, Fen; Wang, Wei-Guang; Jiang, Xin; Wen, Xuan; Hu, Kai-Jin; Xue, Yang

    2017-01-01

    Cathepsin K (CTSK) is a member of cysteine proteinase family, and is predominantly expressed in osteoclastsfor degradationof bone matrix proteins. Given the similarity in physical properties of bone and dental mineralized tissues, including enamel, dentin and cementum, CTSK is likely to take part in mineralization process during odontogenesis. On the other hand, patients with pycnodysostosis caused by mutations of the CTSK gene displayedmultipledental abnormalities, such as hypoplasia of the enamel, obliterated pulp chambers, hypercementosis and periodontal disease. Thereforeitis necessary to study the metabolic role of CTSK in tooth matrix proteins. In this study, BALB/c mice at embryonic day 18 (E18), post-natal day 1 (P1), P5, P10 and P20 were used (5 mice at each time point)for systematic analyses of CTSK expression in the late stage of tooth germ development. We found that CTSK was abundantly expressed in the ameloblasts during secretory and maturation stages (P5 and P10) by immunohistochemistry stainings.During dentinogenesis, the staining was also intense in the mineralization stage (P5 and P10),but not detectable in the early stage of dentin formation (P1) and after tooth eruption (P20).Furthermore, through zymography and digestion test in vitro, CTSK was proved to be capable of hydrolyzing Emdogain and also cleaving Amelogenininto multiple products. Our resultsshed lights on revealing new functions of CTSK and pathogenesis of pycnodysostosis in oral tissues.

  2. Distribution of Cathepsin K in Late Stage of Tooth Germ Development and Its Function in Degrading Enamel Matrix Proteins in Mouse

    PubMed Central

    Jiang, Tao; Liu, Fen; Wang, Wei-Guang; Jiang, Xin; Wen, Xuan; Hu, Kai-Jin; Xue, Yang

    2017-01-01

    Cathepsin K (CTSK) is a member of cysteine proteinase family, and is predominantly expressed in osteoclastsfor degradationof bone matrix proteins. Given the similarity in physical properties of bone and dental mineralized tissues, including enamel, dentin and cementum, CTSK is likely to take part in mineralization process during odontogenesis. On the other hand, patients with pycnodysostosis caused by mutations of the CTSK gene displayedmultipledental abnormalities, such as hypoplasia of the enamel, obliterated pulp chambers, hypercementosis and periodontal disease. Thereforeitis necessary to study the metabolic role of CTSK in tooth matrix proteins. In this study, BALB/c mice at embryonic day 18 (E18), post-natal day 1 (P1), P5, P10 and P20 were used (5 mice at each time point)for systematic analyses of CTSK expression in the late stage of tooth germ development. We found that CTSK was abundantly expressed in the ameloblasts during secretory and maturation stages (P5 and P10) by immunohistochemistry stainings.During dentinogenesis, the staining was also intense in the mineralization stage (P5 and P10),but not detectable in the early stage of dentin formation (P1) and after tooth eruption (P20).Furthermore, through zymography and digestion test in vitro, CTSK was proved to be capable of hydrolyzing Emdogain and also cleaving Amelogenininto multiple products. Our resultsshed lights on revealing new functions of CTSK and pathogenesis of pycnodysostosis in oral tissues. PMID:28095448

  3. Fetal age estimation using MSCT scans of deciduous tooth germs.

    PubMed

    Minier, Marie; Maret, Delphine; Dedouit, Fabrice; Vergnault, Marion; Mokrane, Fathima-Zohra; Rousseau, Hervé; Adalian, Pascal; Telmon, Norbert; Rougé, Daniel

    2014-01-01

    Evaluation of fetal age is an essential element in many fields such as anthropology, odontology, paleopathology, and forensic sciences. This study examines the correlation between fetal age, femoral diaphyseal length (considered as the gold standard), and deciduous tooth germs of fetuses aged 22 to 40 weeks amenorrhea (WA) based on computed tomography (MSCT) reconstructions. Qualitative and quantitative studies of femoral and deciduous tooth germ lengths were performed on 81 fetuses (39 females and 42 males). R software was used for statistical analyses. Intra-observer and inter-observer variabilities and the interclass correlation coefficient (ICC) were calculated. Correlation coefficients (R (2)) and linear regression equations were calculated. Intra- and inter-observer variabilities were very satisfactory (intra-observer ICC ≥ 0.96, inter-observer ICC ≥ 0.95). Femoral length was significantly correlated with age (R (2) = 0.9). The correlation coefficient between age and height, width, and dental volume was R (2) ≥ 0.73. Tooth germs were good indicators of fetal age. Our method appears to be reliable and reproducible, and the results of this study agreed with those of the literature. The dental formula provided a precise estimation of fetal age between 25 and 32 WA. Tooth germs were reliable indicators of fetal age, and multislice computed tomography was shown to be an innovative and reliable technology for this purpose.

  4. Involvement of IGF-2, IGF-1R, IGF-2R and PTEN in development of human tooth germ - an immunohistochemical study.

    PubMed

    Kero, Darko; Cigic, Livia; Medvedec Mikic, Ivana; Galic, Tea; Cubela, Mladen; Vukojevic, Katarina; Saraga-Babic, Mirna

    2016-07-02

    Insulin-Like Growth Factor 2 (IGF-2) is a peptide hormone essential for prenatal growth and development. IGF-2 exerts its mitogenic effects via Insulin-Like Growth Factor 1 Receptor (IGF-1R), and is eliminated by binding to Insulin-Like Growth Receptor 2 (IGF-2R). IGF-2 is also negatively regulated by Phosphatase and Tensin Homolog (PTEN), a phosphatase mutated in various tumors. Not much is known about the interplay between these factors during human odontogenesis. In this study, expression patterns of IGF-2, IGF-1R, IGF-2R and PTEN were analyzed by double immunofluorescence in incisor human tooth germs during the foetal period of development between the 7(th) and 20(th) gestational week. Throughout the investigated period, IGF-2 was mostly expressed in enamel organ, whereas mild to moderate expression of PTEN could be seen in dental papilla and parts of enamel organ. Expression of IGF-1R was ubiquitous and displayed strong intensity throughout the entire enamel organ. In contrast, expression of IGF-2R had rather erratic pattern in enamel organ and dental papilla alike. Expression patterns of IGF-2, IGF-1R, IGF-2R and PTEN in highly proliferative cervical loops, as well as in differentiating pre-ameloblasts and pre-odontoblasts of cusp tip region during the early and late bell stages when enamel organ acquires definitive shape, indicate importance of these factors in crown morphogenesis of human incisor. Taken together, our data suggest the involvement of IGF-2, IGF-1R, IGF-2R and PTEN in temporo-spatial patterning of basic cellular processes (proliferation, differentiation) during normal tooth development. They are also relevant for improving knowledge of molecular basis of human odontogenesis.

  5. Involvement of IGF-2, IGF-1R, IGF-2R and PTEN in development of human tooth germ – an immunohistochemical study

    PubMed Central

    Kero, Darko; Cigic, Livia; Medvedec Mikic, Ivana; Galic, Tea; Cubela, Mladen; Vukojevic, Katarina; Saraga-Babic, Mirna

    2016-01-01

    ABSTRACT Insulin-Like Growth Factor 2 (IGF-2) is a peptide hormone essential for prenatal growth and development. IGF-2 exerts its mitogenic effects via Insulin-Like Growth Factor 1 Receptor (IGF-1R), and is eliminated by binding to Insulin-Like Growth Receptor 2 (IGF-2R). IGF-2 is also negatively regulated by Phosphatase and Tensin Homolog (PTEN), a phosphatase mutated in various tumors. Not much is known about the interplay between these factors during human odontogenesis. In this study, expression patterns of IGF-2, IGF-1R, IGF-2R and PTEN were analyzed by double immunofluorescence in incisor human tooth germs during the foetal period of development between the 7th and 20th gestational week. Throughout the investigated period, IGF-2 was mostly expressed in enamel organ, whereas mild to moderate expression of PTEN could be seen in dental papilla and parts of enamel organ. Expression of IGF-1R was ubiquitous and displayed strong intensity throughout the entire enamel organ. In contrast, expression of IGF-2R had rather erratic pattern in enamel organ and dental papilla alike. Expression patterns of IGF-2, IGF-1R, IGF-2R and PTEN in highly proliferative cervical loops, as well as in differentiating pre-ameloblasts and pre-odontoblasts of cusp tip region during the early and late bell stages when enamel organ acquires definitive shape, indicate importance of these factors in crown morphogenesis of human incisor. Taken together, our data suggest the involvement of IGF-2, IGF-1R, IGF-2R and PTEN in temporo-spatial patterning of basic cellular processes (proliferation, differentiation) during normal tooth development. They are also relevant for improving knowledge of molecular basis of human odontogenesis. PMID:27326759

  6. Appearance pattern of tooth germs with developmental process in Mylopharyngodon piceus

    NASA Astrophysics Data System (ADS)

    Yue, Pei-Qi; Nakajima, Tsuneo

    1995-06-01

    The pharyngeal dental formula of Mylopharyngodon piceus is 4 5 as a rule, and the dentition is asymmetrical. It is difficult to identify each tooth in the larval dentition. In this paper the appearance pattern of tooth germ with development process in this fish is described in detail. The formation pattern of the left dentition is contrasted with that of the right one. In the developmental process, the left pharyngeal dentition lacks teeth at position An3. Thus the left dentition is D-type as designated by Nakajima (1984), while the right one is A-type.

  7. Successful Reconstruction of Tooth Germ with Cell Lines Requires Coordinated Gene Expressions from the Initiation Stage

    PubMed Central

    Komine, Akihiko; Tomooka, Yasuhiro

    2012-01-01

    Tooth morphogenesis is carried out by a series of reciprocal interactions between the epithelium and mesenchyme in embryonic germs. Previously clonal dental epithelial cell (epithelium of molar tooth germ (emtg)) lines were established from an embryonic germ. They were odontogenic when combined with a dental mesenchymal tissue, although the odontogenesis was quantitatively imperfect. To improve the microenvironment in the germs, freshly isolated dental epithelial cells were mixed with cells of lines, and germs were reconstructed in various combinations. The results demonstrated that successful tooth construction depends on the mixing ratio, the age of dental epithelial cells and the combination with cell lines. Analyses of gene expression in these germs suggest that some signal(s) from dental epithelial cells makes emtg cells competent to communicate with mesenchymal cells and the epithelial and mesenchymal compartments are able to progress odontogenesis from the initiation stage. PMID:24710535

  8. PKA regulatory subunit expression in tooth development.

    PubMed

    de Sousa, Sílvia Ferreira; Kawasaki, Katsushige; Kawasaki, Maiko; Volponi, Ana Angelova; Gomez, Ricardo Santiago; Gomes, Carolina Cavaliéri; Sharpe, Paul T; Ohazama, Atsushi

    2014-05-01

    Protein kinase A (PKA) plays critical roles in many biological processes including cell proliferation, cell differentiation, cellular metabolism and gene regulation. Mutation in PKA regulatory subunit, PRKAR1A has previously been identified in odontogenic myxomas, but it is unclear whether PKA is involved in tooth development. The aim of the present study was to assess the expression of alpha isoforms of PKA regulatory subunit (Prkar1a and Prkar2a) in mouse and human odontogenesis by in situ hybridization. PRKAR1A and PRKAR2A mRNA transcription was further confirmed in a human deciduous germ by qRT-PCR. Mouse Prkar1a and human PRKAR2A exhibited a dynamic spatio-temporal expression in tooth development, whereas neither human PRKAR1A nor mouse Prkar2a showed their expression in odontogenesis. These isoforms thus showed different expression pattern between human and mouse tooth germs. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. On the analysis of neonatal hamster tooth germs with the photon microprobe at Daresbury, UK

    NASA Astrophysics Data System (ADS)

    Tros, G. H. J.; Van Langevelde, F.; Vis, R. D.

    1990-04-01

    Complementary to the micro-PIXE experiments performed on hamster tooth germs to elucidate the role of fluoride during the growth, the photon microprobe at Daresbury was used to obtain information on the distribution of Zn. The germs of fluoride-administered hamsters, together with a control group, were analyzed with the micro-synchrotron radiation fluorescence method (micro-SXRF).

  10. Histological and immunohistochemical analyses of molar tooth germ in enamelin-deficient mouse.

    PubMed

    Sawada, Takashi; Sekiguchi, Hiroshi; Uchida, Takashi; Yamashita, Haruto; Shintani, Seikou; Yanagisawa, Takaaki

    2011-09-01

    Amelogenesis imperfecta (AI) is associated with mutations in a number of genes, including AMELX and ENAM. However, the precise mechanism leading to enamel malformation in different AI types remains to be elucidated. In the present study, we investigated morphological change in tooth germ obtained from ENAM-mutant mice (Enam(Rgsc521) homozygotes) as a model for human AI using histological and immunohistochemical methodologies. The results showed that ameloblasts detached from developing dentin and lost cell polarity in mutant mice at post-natal day 3. Cyst-like structures, including amelogenin-immunopositive materials, were observed between these detached cells and the dentin. No enamel-like structure, however, was observed in the cusp of the crown. These results suggest that enamelin acts as an adhesion molecule and is involved in ameloblast cell differentiation during the early stages of tooth development. Copyright © 2010 Elsevier GmbH. All rights reserved.

  11. Reptilian tooth development.

    PubMed

    Richman, Joy M; Handrigan, Gregory R

    2011-04-01

    Dental patterns in vertebrates range from absence of teeth to multiple sets of teeth that are replaced throughout life. Despite this great variation, most of our understanding of tooth development is derived from studies on just a few model organisms. Here we introduce the reptile as an excellent model in which to study the molecular basis for early dental specification and, most importantly, for tooth replacement. We review recent snake studies that highlight the conserved role of Shh in marking the position of the odontogenic band. The distinctive molecular patterning of the dental lamina in the labial-lingual and oral-aboral axes is reviewed. We explain how these early signals help to specify the tooth-forming and non-tooth forming sides of the dental lamina as well as the presumptive successional lamina. Next, the simple architecture of the reptilian enamel organ is contrasted with the more complex, mammalian tooth bud and we discuss whether or not there is an enamel knot in reptilian teeth. The role of the successional lamina during tooth replacement in squamate reptiles is reviewed and we speculate on the possible formation of a vestigial, post-permanent dentition in mammals. In support of these ideas, we present data on agamid teeth in which development of a third generation is arrested. We suggest that in diphyodont mammals, similar mechanisms may be involved in reducing tooth replacement capacity. Finally, we review the location of label-retaining cells and suggest ways in which these putative dental epithelial stem cells contribute to continuous tooth replacement. Copyright © 2011 Wiley-Liss, Inc.

  12. The dentin sialoprotein (DSP) expression in rat tooth germs following fluoride treatment: an immunohistochemical study.

    PubMed

    Maciejewska, Izabela; Spodnik, Jan Henryk; Wójcik, Sławomir; Domaradzka-Pytel, Beata; Bereznowski, Zdzisław

    2006-03-01

    Fluoride is known to alter expression of dentin matrix proteins and affect their posttranslational modifications. The objective of our study was to examine dentin sialoprotein (DSP) expression in the early and late bell stages of development of the first molar tooth germs in rats treated with fluoride. Pregnant dumps were divided into three groups. They were fed a standard diet and from the fifth day of pregnancy, each group received either tap water (with trace amounts of fluoride), tap water with a low concentration of fluoride, or tap water with a high concentration of fluoride. Changes in DSP expression and distribution were visualized by immunohistochemistry. Immunoreactivity for DSP was detected in the cervical regions of the early bell stage in tooth germs of the 1-day-old animals. The earliest reaction was visible in the control group and the group supplemented with the low fluoride concentration (F(L)) but not in the group supplemented with the high fluoride concentration (F(H)). In early bell stages across all experimental groups, the immunoreactivity to DSP was observed in the cusp tip regions and was localized to preameloblasts, young and mature odontoblasts, dental pulp cells, predentin, and dentin. Generally, more intense positive staining for DSP was detected in animals supplemented with the high fluoride concentration. In the late bell stage found in the 4-day-old control group and the group supplemented with the low fluoride concentration, immunoreactivity for DSP was less intense compared with younger animals. However, immunoreactivity was greater in the group treated with the high dose of fluoride. In this group, the positive immunostaining for DSP, especially in young ameloblasts, was prolonged and relatively strong. Fluoride supplementation causes changes in the developmental pattern of DSP expression and its distribution in rat tooth germs.

  13. [The role of pulp in the root resorption of primary teeth without permanent tooth germs].

    PubMed

    Lin, Bi-chen; Yang, Jie; Zhao, Yu-ming; Ge, Li-hong

    2011-03-01

    To investigate the role of pulp in the root resorption of primary teeth without permanent tooth germs. The animal model without permanent tooth germs was established by surgery in Beagle dog. The root resorption was observed by taking periapical radiographs periodically. The samples of mandibular bone and pulp at different resorption stages were collected. The distribution of odontoclasts and the activating factor was analyzed by histological staining and semiquantitative reverse transcriptase polymerase chain reaction (RT-PCR). The role of pulp in the root resorption of primary teeth was tested by early pulpectomy. In the root resorption of primary molars without permanent teeth germs, a large number of odontoclasts were present on the pulpal surface of the root canal. Semi-quantification RT-PCR showed that the ratios of the expression of receptor activator of NF-κB ligand (RANKL) mRNA and β-actin in the pulp of permanent teeth and primary teeth without permanent teeth germ during different periods of root resorption are 0.1314, 0.1901, 0.2111 and 0.6058 (P > 0.05). The root resorption of primary teeth without permanent teeth germs in test groups was about 5 weeks later than that of control group. The pulp of primary tooth played an important role in the root resorption of primary tooth without permanent tooth germ.

  14. Prenatal ultrasound and postmortem histologic evaluation of tooth germs: an observational, transversal study.

    PubMed

    Seabra, Mariana; Felino, António; Nogueira, Rosete; Valente, Francisco; Braga, Ana Cristina; Vaz, Paula

    2015-05-12

    Hypodontia is the most frequent developmental anomaly of the orofacial complex, and its detection in prenatal ultrasound may indicate the presence of congenital malformations, genetic syndromes and chromosomal abnormalities. To date, only a few studies have evaluated the histological relationship of human tooth germs identified by two-dimensional (2D) ultrasonography. In order to analyze whether two-dimensional ultrasonography of tooth germs may be successfully used for identifying genetic syndromes, prenatal ultrasound images of fetal tooth germs obtained from a Portuguese population sample were compared with histological images obtained from fetal autopsies. Observational, descriptive, transversal study. The study protocol followed the ethical principles outlined by the Helsinki Declaration and was approved by the Ethics Committee of the School of Dental Medicine, University of Porto (FMDUP, Porto, Portugal) and of the Centro Hospitalar de Vila Nova de Gaia/Espinho (CHVNG/EPE, Porto, Portugal) as well as by the CGC Genetics Embryofetal Pathology Laboratory. Eighty-five fetuses examined by prenatal ultrasound screening from May 2011 to August 2012 had an indication for autopsy following spontaneous fetal death or medical termination of pregnancy. Of the 85 fetuses, 37 (43.5%) were randomly selected for tooth germ evaluation by routine histopathological analysis. Fetuses who were up to 30 weeks of gestation, and whose histological pieces were not representative of all maxillary tooth germs was excluded. Twenty four fetus between the 13(th) and 30(th) weeks of gestation fulfilled the parameters to autopsy. Twenty four fetuses were submitted to histological evaluation and were determined the exact number, morphology, and mineralization of their tooth germs. All tooth germs were identifiable with ultrasonography as early as the 13(th) week of gestation. Of the fetuses autopsied, 41.7% had hypodontia (29.1% maxillary hypodontia and 20.9% mandibular hypodontia). This

  15. Modification of tooth development by heat shock protein 60.

    PubMed

    Papp, Tamas; Polyak, Angela; Papp, Krisztina; Meszar, Zoltan; Zakany, Roza; Meszar-Katona, Eva; Tünde, Palne Terdik; Ham, Chang Hwa; Felszeghy, Szabolcs

    2016-03-30

    Although several heat shock proteins have been investigated in relation to tooth development, no available information is available about the spatial and temporal expression pattern of heat shock protein 60 (Hsp 60). To characterize Hsp 60 expression in the structures of the developing tooth germ, we used Western blotting, immunohistochemistry and in situ hybridization. Hsp 60 was present in high amounts in the inner and outer enamel epithelia, enamel knot (EK) and stratum intermedium (SI). Hsp 60 also appeared in odontoblasts beginning in the bell stage. To obtain data on the possible effect of Hsp 60 on isolated lower incisors from mice, we performed in vitro culturing. To investigate the effect of exogenous Hsp 60 on the cell cycle during culturing, we used the 5-bromo-2-deoxyuridine (BrdU) incorporation test on dental cells. Exogenously administered Hsp 60 caused bluntness at the apical part of the 16.5-day-old tooth germs, but it did not influence the proliferation rate of dental cells. We identified the expression of Hsp 60 in the developing tooth germ, which was present in high concentrations in the inner and outer enamel epithelia, EK, SI and odontoblasts. High concentration of exogenous Hsp 60 can cause abnormal morphology of the tooth germ, but it did not influence the proliferation rate of the dental cells. Our results suggest that increased levels of Hsp 60 may cause abnormalities in the morphological development of the tooth germ and support the data on the significance of Hsp during the developmental processes.

  16. Expression of aquaporin isoforms during human and mouse tooth development.

    PubMed

    Felszeghy, S; Módis, L; Németh, P; Nagy, G; Zelles, T; Agre, P; Laurikkala, J; Fejerskov, O; Thesleff, I; Nielsen, S

    2004-04-01

    Previously, we described the development of hyaluronan (HA) deposition in human tooth germ tissues that are consistent with water transport in different stages of tooth development. The aquaporins (AQP) constitute a family of membrane water channels that are expressed in many organs. However, there are no data available about the expression pattern of aquaporin water channels in dental structures. In the present study we have characterised the expression of six different aquaporin isoforms (AQP1-5, AQP-9) in developing human and mouse tooth germs by immunohistochemistry using isoform specific antibodies. In the "bell stage" AQP1 was expressed in endothelial cells of small vessels whereas no other structures of the tooth primordial were labeled. AQP2, AQP3 and AQP9 immunoreactivity was not observed in tooth germs, whereas strong AQP4 and AQP5 expression was observed in dental lamina, inner enamel epithelium, stratum intermedium, stellate reticulum and the outer enamel epithelium. Oral epithelium also exhibited AQP4 and AQP5 immunolabeling. During development of the matrices of the dental hard tissues AQP4 and AQP5 immunostaining was observed in the odontoblasts and their processes, as well as in the secretory ameloblast and their apical processes. Immunolabeling controls were negative. In conclusion, AQP4 and AQP5 are expressed in tooth germ tissues in early development in cells that previously have been shown to express HA and/or CD44, indicating that AQP water channels may play a role for ECM hydration during tooth development.

  17. Exogenous fibroblast growth factor 8 rescues development of mouse diastemal vestigial tooth ex vivo.

    PubMed

    Li, Lu; Yuan, Guohua; Liu, Chao; Zhang, Lu; Zhang, Yanding; Chen, YiPing; Chen, Zhi

    2011-06-01

    Regression of vestigial tooth buds results in the formation of the toothless diastema, a unique feature of the mouse dentition. Revitalization of the diastemal vestigial tooth bud provides an excellent model for studying tooth regeneration and replacement. It has been previously shown that suppression of fibroblast growth factor (FGF) signaling in the diastema results in vestigial tooth bud regression. In this study, we report that application of exogenous FGF8 to the mouse embryonic diastemal region rescues diastemal tooth development. However, this rescue of diastemal tooth development occurs only in an isolated diastemal regions and not in the mandibular quadrant, which includes the incisor and molar germs. FGF8 promotes cell proliferation and inhibits apoptosis in diastemal tooth epithelium, and revitalizes the tooth developmental program, as evidenced by the expression of genes critical for normal tooth development. Our results also support the idea that the adjacent tooth germs contribute to the suppression of diastemal vestigial tooth buds by means of multiple signals.

  18. Exogenous FGF8 rescues development of mouse diastemal vestigial tooth ex vivo

    PubMed Central

    Li, Lu; Yuan, Guohua; Liu, Chao; Zhang, Lu; Zhang, Yanding; Chen, YiPing; Chen, Zhi

    2011-01-01

    Regression of vestigial tooth buds results in the formation of the toothless diastema, a unique feature of the mouse dentition. Revitalization of the diastemal vestigial tooth bud provides an excellent model for studying tooth regeneration and replacement. It was shown previously that suppression of FGF signaling in the diastema is a causative of vestigial tooth bud regression. In this study, we report that application of exogenous FGF8 to the mouse embryonic diastemal region rescues diastemal tooth development. However, this rescue of diastemal tooth development occurs only in isolated diastemal region, but not in mandibular quadrant containing incisor and molar germs. FGF8 promotes cell proliferation and inhibits apoptosis in diastemal tooth epithelium, and revitalizes tooth developmental program, evidenced by the expression of genes critical for normal tooth development. Our results support the idea that the adjacent tooth germs contribute to the suppression of diastemal vestigial tooth buds via multiple signals. PMID:21412937

  19. Leptin and vascular endothelial growth factor regulate angiogenesis in tooth germs.

    PubMed

    Ide, Shinji; Tokuyama, Reiko; Davaadorj, Purevsuren; Shimozuma, Masashi; Kumasaka, Shuku; Tatehara, Seiko; Satomura, Kazuhito

    2011-03-01

    Leptin, a 16 kDa non-glycolated polypeptide of 146 amino acids produced by the ob gene, has a variety of physiological roles not only in lipid metabolism, hematopoiesis, thermogenesis and ovarian function, but also in angiogenesis. This study focuses to investigate the possibility that leptin, as an angiogenic factor, may regulate the angiogenesis during tooth development. We firstly studied the expression of leptin and vascular endothelial growth factor (VEGF) during tooth development immunohistochemically. This investigation revealed that leptin is expressed in ameloblasts, odontoblasts, dental papilla cells and stratum intermedium cells. This expression pattern was similar to that of VEGF, one of the most potent angiogenic factors. Interestingly, more leptin-positive cells were observed in the upper third portion of dental papilla, which is closest to odontoblastic layer, compared to middle and lower thirds. Moreover, in the dental papilla, more CD31 and/or CD34-positive vascular endothelial cells were observed in the vicinity of ameloblasts and odontoblasts expressing leptin and VEGF. These findings strongly suggest that ameloblasts, odontoblasts and dental papilla cells induce the angiogenesis in tooth germs by secretion of leptin as well as VEGF.

  20. Contribution of donor and host mesenchyme to the transplanted tooth germs.

    PubMed

    Nakaki, T; Saito, K; Ida-Yonemochi, H; Nakagawa, E; Kenmotsu, S; Ohshima, H

    2015-01-01

    Autologous tooth germ transplantation of immature teeth is an alternative method of tooth replacement that could be used instead of dental implants in younger patients. However, it is paramount that the dental pulp remain vital and that root formation continue in the transplanted location. The goal of this study is to characterize the healing of allogenic tooth grafts in an animal model using GFP-labeled donor or host postnatal mice. In addition, the putative stem cells were labeled before transplantation with a pulse-chase paradigm. Transplanted molars formed cusps and roots and erupted into occlusion by 2 wk postoperatively. Host label-retaining cells (LRCs) were maintained in the center of pulp tissue associating with blood vessels. Dual labeling showed that a proportion of LRCs were incorporated into the odontoblast layer. Host cells, including putative dendritic cells and the endothelium, also immigrated into the pulp tissue but did not contribute to the odontoblast layer. Therefore, LRCs or putative mesenchymal stem cells are retained in the transplanted pulps. Hertwig's epithelial root sheath remains vital, and epithelial LRCs are present in the donor cervical loops. Thus, the dynamic donor-host interaction occurred in the developing transplant, suggesting that these changes affect the characteristics of the dental pulp. © International & American Associations for Dental Research 2014.

  1. Micro-PIXE (proton-induced X-ray emission) study of the effects of fluoride on mineral distribution patterns in enamel and dentin in the developing hamster tooth germ

    SciTech Connect

    Lyaruu, D.M.; Tros, G.H.; Bronckers, A.L.; Woeltgens, J.H. )

    1990-06-01

    Micro-PIXE (proton-induced X-ray emission) analysis was performed on unfixed and anhydrously prepared sections from developing enamel and dentin from hamsters injected with a single dose of 20 mg NaF/kg body weight. Fluoride, apart from inducing the formation of the characteristic paired response in the enamel (i.e., a hyper- followed by a hypomineralized band in the secretory enamel), also induces the formation of sub-ameloblastic cystic lesions under the transitional and early secretory enamel accompanied by relatively intense hypermineralization of the underlying cystic enamel surface. These cystic lesions, however, were only found to be associated with certain isolated populations of these cells. In addition, these lesions were restricted to the smooth surfaces of the tooth germ only. Cystic lesions such as those seen under the transitional and early secretory ameloblasts were not observed under the fully secretory or maturation stage ameloblasts. Why fluoride induces the formation of cystic lesions in some ameloblast populations while other cells in the same stage of development apparently remain unaffected, is a matter which needs further investigation.

  2. BMP4 signaling mediates Zeb family in developing mouse tooth.

    PubMed

    Shin, Jeong-Oh; Kim, Eun-Jung; Cho, Kyoung-Won; Nakagawa, Eizo; Kwon, Hyuk-Jae; Cho, Sung-Won; Jung, Han-Sung

    2012-06-01

    Tooth morphogenesis is regulated by sequential and reciprocal interaction between oral epithelium and neural-crest-derived ectomesenchyme. The interaction is controlled by various signal molecules such as bone morphogenetic protein (BMP), Hedgehog, fibroblast growth factor (FGF), and Wnt. Zeb family is known as a transcription factor, which is essential for neural development and neural-crest-derived tissues, whereas the role of the Zeb family in tooth development remains unclear. Therefore, this study aimed to investigate the expression profiles of Zeb1 and Zeb2 during craniofacial development focusing on mesenchyme of palate, hair follicle, and tooth germ from E12.5 to E16.5. In addition, we examined the interaction between Zeb family and BMP4 during tooth development. Both Zeb1 and Zeb2 were expressed at mesenchyme of the palate, hair follicle, and tooth germ throughout the stages. In the case of tooth germ at the cap stage, the expression of Zeb1 and Zeb2 was lost in epithelium-separated dental mesenchyme. However, the expression of Zeb1 and Zeb2 in the dental mesenchyme was recovered by Bmp4 signaling via BMP4-soaked bead and tissue recombination. Our results suggest that Zeb1 and Zeb2, which were mediated by BMP4, play an important role in neural-crest-derived craniofacial organ morphogenesis, such as tooth development.

  3. Immunohistochemical expression of E-cadherin and beta-catenin in ameloblastomas and tooth germs.

    PubMed

    Alves Pereira, Karuza Maria; do Amaral, Bruna Aguiar; dos Santos, Bruna Rafaela Martins; Galvão, Hébel Cavalcanti; Freitas, Roseana de Almeida; de Souza, Lélia Batista

    2010-03-01

    The aim was to analyze the expression of E-cadherin and beta-catenin in ameloblastomas and tooth germs to determine their roles in cell differentiation processes and invasiveness compared with odontogenesis. Twenty-one ameloblastoma cases (16 solid and 5 unicystic tumors) and 5 tooth germs were submitted to the immunohistochemical detection of E-cadherin and beta-catenin. Immunoreactivity was evaluated using descriptive and semiquantitative analysis, investigating the location and intensity of staining. The Fisher exact test was performed, and P values of <.05 were considered to indicate statistical significance. There was no statistically significant difference in the expression of E-cadherin and beta-catenin between solid and unicystic ameloblastomas (P = .59; P = .63; respectively). The same was found when comparing solid and unicystic ameloblastomas with the tooth germs for both E-cadherin (P = .53; P = .44; respectively) and beta-catenin (P = .12; P = .16; respectively). Nuclear staining of beta-catenin was observed in only 4 cases (3 solid and 1 unicystic tumor). The results showed no differences in the expression of E-cadherin or beta-catenin between tooth germs and solid and unicystic ameloblastomas. The expression of these molecules seems mainly to be related to the process of cell differentiation. Copyright 2010 Mosby, Inc. All rights reserved.

  4. [Growth factors in human tooth development].

    PubMed

    Bellone, C; Barni, T; Pagni, L; Balboni, G C; Vannelli, G B

    1990-03-01

    Our research concerns the immunohistochemical localization of EGF and IGF-I receptors in the tooth germ, using monoclonal antibodies. The results show that in the early phases of human tooth development EGF and IGF-I receptors are present. At bud stage both receptors are localized at dental laminae level, in some epithelial cells of the tooth bud and in some mesenchymal cells. At cap stage the receptors are present in the outer and inner enamel epithelium, and in some cells of stellate reticulum. As far as concerns the mesenchymal cells, some cells of dental papilla in contact with enamel organ, are intensely positive. The immunopositivity is present also in some mesenchymal cells at follicular level. At late cap stage and at early bell stage receptors are not present at inner enamel epithelium level but they can be detectable in the mesenchyma of dental papilla and in some cells of the follicle. On the basis of these results it may be hypothesized that EGF and IGF-I can act as growth factors in the modulation of cellular proliferation and differentiation during the human tooth morphogenesis. Moreover, it is possible that these substances can play a role in the mesenchymal-epithelial interaction in the developing human tooth.

  5. Bivalent histone modifications during tooth development.

    PubMed

    Zheng, Li-Wei; Zhang, Bin-Peng; Xu, Ruo-Shi; Xu, Xin; Ye, Ling; Zhou, Xue-Dong

    2014-12-01

    Histone methylation is one of the most widely studied post-transcriptional modifications. It is thought to be an important epigenetic event that is closely associated with cell fate determination and differentiation. To explore the spatiotemporal expression of histone H3 lysine 4 trimethylation (H3K4me3) and histone H3 lysine 27 trimethylation (H3K27me3) epigenetic marks and methylation or demethylation transferases in tooth organ development, we measured the expression of SET7, EZH2, KDM5B and JMJD3 via immunohistochemistry and quantitative polymerase chain reaction (qPCR) analysis in the first molar of BALB/c mice embryos at E13.5, E15.5, E17.5, P0 and P3, respectively. We also measured the expression of H3K4me3 and H3K27me3 with immunofluorescence staining. During murine tooth germ development, methylation or demethylation transferases were expressed in a spatial-temporal manner. The bivalent modification characterized by H3K4me3 and H3K27me3 can be found during the tooth germ development, as shown by immunofluorescence. The expression of SET7, EZH2 as methylation transferases and KDM5B and JMJD3 as demethylation transferases indicated accordingly with the expression of H3K4me3 and H3K27me3 respectively to some extent. The bivalent histone may play a critical role in tooth organ development via the regulation of cell differentiation.

  6. Modification of tooth development by heat shock protein 60

    PubMed Central

    Papp, Tamas; Polyak, Angela; Papp, Krisztina; Meszar, Zoltan; Zakany, Roza; Meszar-Katona, Eva; Tünde, Palne Terdik; Ham, Chang Hwa; Felszeghy, Szabolcs

    2016-01-01

    Although several heat shock proteins have been investigated in relation to tooth development, no available information is available about the spatial and temporal expression pattern of heat shock protein 60 (Hsp 60). To characterize Hsp 60 expression in the structures of the developing tooth germ, we used Western blotting, immunohistochemistry and in situ hybridization. Hsp 60 was present in high amounts in the inner and outer enamel epithelia, enamel knot (EK) and stratum intermedium (SI). Hsp 60 also appeared in odontoblasts beginning in the bell stage. To obtain data on the possible effect of Hsp 60 on isolated lower incisors from mice, we performed in vitro culturing. To investigate the effect of exogenous Hsp 60 on the cell cycle during culturing, we used the 5-bromo-2-deoxyuridine (BrdU) incorporation test on dental cells. Exogenously administered Hsp 60 caused bluntness at the apical part of the 16.5-day-old tooth germs, but it did not influence the proliferation rate of dental cells. We identified the expression of Hsp 60 in the developing tooth germ, which was present in high concentrations in the inner and outer enamel epithelia, EK, SI and odontoblasts. High concentration of exogenous Hsp 60 can cause abnormal morphology of the tooth germ, but it did not influence the proliferation rate of the dental cells. Our results suggest that increased levels of Hsp 60 may cause abnormalities in the morphological development of the tooth germ and support the data on the significance of Hsp during the developmental processes. PMID:27025262

  7. Immunoexpression of integrins in ameloblastoma, adenomatoid odontogenic tumor, and human tooth germs.

    PubMed

    de Souza Andrade, Emanuel Sávio; Miguel, Márcia Cristina da Costa; de Almeida Freitas, Roseana; Pereira Pinto, Leão; Batista de Souza, Lélia

    2008-07-01

    The expression of integrins alpha2beta1, alpha3beta1, and alpha5beta1 in 30 ameloblastomas (20 solid and 10 unicystic tumors), 12 adenomatoid odontogenic tumors (AOTs), and 5 human tooth germs in different stages of odontogenesis was analyzed. The distribution, location, pattern, and intensity of immunohistochemical expression were evaluated. Intensity was analyzed using scores (0 = absence, 1 = weak staining, and 2 = strong staining). No difference in the immunoexpression of the integrins was observed between solid and unicystic ameloblastomas. When these two ameloblastoma types were pooled into a single group, the following significant differences were found: immunoexpression of integrin alpha2beta1 was stronger in ameloblastomas than in AOTs and tooth germs, and the expression of integrin alpha5beta1 was stronger in ameloblastomas than in AOTs. The lack of detection of integrin alpha3beta1 in tooth germs and its detection in the odontogenic tumors studied suggest that this integrin might be used as a marker of neoplastic transformation in odontogenic tissues.

  8. [Effects of 1-hydroxyethylidene-1,1-bisphosphonate (HEBP) on the formation of dental hard tissue of mouse molar tooth germs in organ culture system].

    PubMed

    Daigo, Tsuyoshi

    2003-06-01

    In the developing tooth, 1-hydroxyethylidene-1,1-bisphosphonate (HEBP) causes hypoplasia and hypomineralization of enamel and dentine. The present study was undertaken to clarify the effects of HEBP on the formation of dental tissues of tooth germs in an organ culture system. Mandibular first molars from 17.5-day-old mouse embryos were cultured with or without 250 microM HEBP in culture medium. Cultured tooth germs were analyzed by histological examination and by immunohistochemical localization using anti-amelogenin antibody. In cultured tooth germs treated with HEBP before the commencement of calcification in dentine, calcification of dentine matrix was inhibited completely and enamel formation was not observed. Ameloblasts were directly adjacent to dentine matrix. However, immunohistochemical data indicated that these ameloblasts secreted amelogenin. In the experiments of adding HEBP to cultured tooth germs on culture day 13, calcified dentine and enamel had formed before the administration of HEBP, but the dentine matrix newly formed after the administration of HEBP had not calcified. It was confirmed by immunohistochemical observations that enamel matrix-like material had penetrated into uncalcified dentine matrix and accumulated in dental papilla of tooth germs. However, no enamel matrix-like material was observed in calcified dentine and predentine underneath the calcified dentine by immunohistochemical staining. From these results, it might be concluded that ameloblasts secreted enamel matrix in the presence of HEBP and diffused through uncalcified dentine matrix into dental papilla. These findings suggests the calcification of dentine might be essential for the physical barrier to accumulate the enamel matrix and form a distinct layer of enamel as enamel.

  9. ClC-7 Deficiency Impairs Tooth Development and Eruption

    PubMed Central

    Wang, He; Pan, Meng; Ni, Jinwen; Zhang, Yanli; Zhang, Yutao; Gao, Shan; Liu, Jin; Wang, Zhe; Zhang, Rong; He, Huiming; Wu, Buling; Duan, Xiaohong

    2016-01-01

    CLCN7 gene encodes the voltage gated chloride channel 7 (ClC-7) in humans. The mutations in CLCN7 have been associated with osteopetrosis in connection to the abnormal osteoclasts functions. Previously, we found that some osteopetrosis patients with CLCN7 mutations suffered from impacted teeth and root dysplasia. Here we set up two in vivo models under a normal or an osteoclast-poor environment to investigate how ClC-7 affects tooth development and tooth eruption. Firstly, chitosan-Clcn7-siRNA nanoparticles were injected around the first maxillary molar germ of newborn mice and caused the delay of tooth eruption and deformed tooth with root dysplasia. Secondly, E13.5 molar germs infected with Clcn7 shRNA lentivirus were transplanted under the kidney capsule and presented the abnormal changes in dentin structure, periodontal tissue and cementum. All these teeth changes have been reported in the patients with CLCN7 mutation. In vitro studies of ameloblasts, odontoblasts and dental follicle cells (DFCs) were conducted to explore the involved mechanism. We found that Clcn7 deficiency affect the differentiation of these cells, as well as the interaction between DFCs and osteoclasts through RANKL/OPG pathway. We conclude that ClC-7 may affect tooth development by directly targeting tooth cells, and regulate tooth eruption through DFC mediated osteoclast pathway. PMID:26829236

  10. [Auto-transplantation of tooth germs. Discussion and presentation of 3 treated cases].

    PubMed

    Massei, G; Cardesi, E

    1997-01-01

    The authors examine the theoretical possibilities of human dental transplants: autologous, homologous and heterologous. They, then discuss-with reference to autologous transplants-an autotransplant as an alternative to prosthodontic treatment. This would apply both to traditional prosthodontic treatment and on implants or orthodontic treatment aiming at filling dental gaps. They show both general and local counterindications against this operational method the knowledge of which is necessary for an adequate selection of patients. They stress the determining factors for a successful autotransplant: 1) particular care with the choice of the germ to be transplanted taking into account its morphology and the stage of root development; 2) adequate surgical preparation of the receiving site in relation to the size of the germ to be transplanted; 3) suitable surgical technique entailing a particular care in the manipulation of soft and hard tissues and of the germ and appropriate conditions of sterilization; 4) use of appropriate retention means to ensure stability of the transplanted germ so as to favour cellular proliferation and reduce osteoclastic activity; 5) reduction of occlusal pressure on the transplanted germ. The authors describe for example's sake 3 out of 32 cases treated with the documentation of the achieved long-term success. They also analyse the possible causes of failure of such operational method (careless manipulation of the germ, incorrect surgical technique, removal of the germ in a too early stage of its development, too long exposure of the germ outside the oral cavity, poor oral hygiene, caries, periodontal disease, occlusal trauma.

  11. Transcriptomic profiling comparison of YAP over-expression and conditional knockout mouse tooth germs.

    PubMed

    Liu, Ming; Wang, Xiu-Ping

    2015-09-01

    To identify the downstream target genes of YAP, we used RNA-Seq technology to compare the transcriptomic profilings of Yap conditional knockout (Yap CKO) and YAP over-expression mouse tooth germs. Our results showed that some Hox, Wnt and Laminin family genes had concurrent changes with YAP transcripts, indicating that the expression of these genes may be regulated by YAP. Here, we provide the detailed experimental procedure for the transcriptomic profiling results (NCBI GEO accession number GSE65524). The associated study on the regulation of Hoxa1 and Hoxc13 genes by YAP was published in Molecular Cellular Biology in 2015 [Liu et al., 2015].

  12. Transport of germ plasm on astral microtubules directs germ cell development in Drosophila

    PubMed Central

    Lerit, Dorothy A.; Gavis, Elizabeth R.

    2011-01-01

    Summary Background In many organisms, germ cells are segregated from the soma through the inheritance of the specialized germ plasm, which contains mRNAs and proteins that specify germ cell fate and promote germline development. Whereas germ plasm assembly has been well characterized, mechanisms mediating germ plasm inheritance are poorly understood. In the Drosophila embryo, germ plasm is anchored to the posterior cortex and nuclei that migrate into this region give rise to the germ cell progenitors, or pole cells. How the germ plasm interacts with these nuclei for pole cell induction and is selectively incorporated into the forming pole cells is not known. Results Live imaging of two conserved germ plasm components, nanos mRNA and Vasa protein, revealed that germ plasm segregation is a dynamic process involving active transport of germ plasm RNA-protein complexes coordinated with nuclear migration. We show that centrosomes accompanying posterior nuclei induce release of germ plasm from the cortex and recruit these components by dynein-dependent transport on centrosome-nucleated microtubules. As nuclei divide, continued transport on astral microtubules partitions germ plasm to daughter nuclei, leading to its segregation into pole cells. Disruption of these transport events prevents incorporation of germ plasm into pole cells and impairs germ cell development. Conclusions Our results indicate that active transport of germ plasm is essential for its inheritance and ensures the production of a discrete population of germ cell progenitors endowed with requisite factors for germline development. Transport on astral microtubules may provide a general mechanism for the effective segregation of cell fate determinants. PMID:21376599

  13. Porcine tooth germ cell conditioned medium can induce odontogenic differentiation of human dental pulp stem cells.

    PubMed

    Wang, Yin-Xiong; Ma, Zhao-Feng; Huo, Na; Tang, Liang; Han, Chun; Duan, Yin-Zhong; Jin, Yan

    2011-05-01

    It is suggested that the differentiation of tooth-derived stem cells is modulated by the local microenvironment in which they reside. Previous studies have indicated that tooth germ cell-conditioned medium (TGC-CM) holds the potential to induce dental pulp stem cells (DPSCs) to differentiate into the odontogenic lineage. Nevertheless, human TGC-CM (hTGC-CM) is not feasible in practical application, so we conjectured that xenogenic TGC-CM might exert a similar influence on human dental stem cells. In this study, we chose swine as the xenogenic origin and compared the effect of porcine tooth germ cell-conditioned medium (pTGC-CM) with its human counterpart on human DPSCs. Morphological appearance, colony-forming assay, in vitro multipotential ability, protein and gene expression of the odontogenic phenotype and the in vivo differentiation capacity of DPSCs were evaluated. The results showed that pTGC-CM exerted a similar effect to hTGC-CM in inducing human DPSCs to present odontogenic changes, which were indicated by remarkable morphological changes, higher multipotential capability and the expression of some odontogenic markers in gene and protein levels. Besides, the in vivo results showed that pTGC-CM-treated DPSCs, similar to hTGC-CM-treated DPSCs, could form a more regular dentine-pulp complex. Our data provided the first evidence that pTGC-CM is able to exert almost the same effect on DPSCs with hTGC-CM. The observations suggest that the application of xenogenic TGC-CM may facilitate generating bioengineered teeth from tooth-derived stem cells in future.

  14. Inhibition of apoptosis in early tooth development alters tooth shape and size.

    PubMed

    Kim, J-Y; Cha, Y-G; Cho, S-W; Kim, E-J; Lee, M-J; Lee, J-M; Cai, J; Ohshima, H; Jung, H-S

    2006-06-01

    Apoptosis plays important roles in various stages of organogenesis. In this study, we hypothesized that apoptosis would play an important role in tooth morphogenesis. We examined the role of apoptosis in early tooth development by using a caspase inhibitor, z-VAD-fmk, concomitant with in vitro organ culture and tooth germ transplantation into the kidney capsule. Inhibition of apoptosis at the early cap stage did not disrupt the cell proliferation level when compared with controls. However, the macroscopic morphology of mice molar teeth exhibited dramatic alterations after the inhibition of apoptosis. Crown height was reduced, and mesiodistal diameter was increased in a concentration-dependent manner with z-VAD-fmk treatment. Overall, apoptosis in the enamel knot would be necessary for the proper formation of molar teeth, including appropriate shape and size.

  15. Genomic Landscape of Developing Male Germ Cells

    PubMed Central

    Lee, Tin-Lap; Pang, Alan Lap-Yin; Rennert, Owen M.; Chan, Wai-Yee

    2010-01-01

    Spermatogenesis is a highly orchestrated developmental process by which spermatogonia develop into mature spermatozoa. This process involves many testis- or male germ cell-specific gene products whose expressions are strictly regulated. In the past decade the advent of high-throughput gene expression analytical techniques has made functional genomic studies of this process, particularly in model animals such as mice and rats, feasible and practical. These studies have just begun to reveal the complexity of the genomic landscape of the developing male germ cells. Over 50% of the mouse and rat genome are expressed during testicular development. Among transcripts present in germ cells, 40% – 60% are uncharacterized. A number of genes, and consequently their associated biological pathways, are differentially expressed at different stages of spermatogenesis. Developing male germ cells present a rich repertoire of genetic processes. Tissue-specific as well as spermatogenesis stage-specific alternative splicing of genes exemplifies the complexity of genome expression. In addition to this layer of control, discoveries of abundant presence of antisense transcripts, expressed psuedogenes, non-coding RNAs (ncRNA) including long ncRNAs, microRNAs (miRNAs) and Piwi-interacting RNAs (piRNAs), and retrogenes all point to the presence of multiple layers of expression and functional regulation in male germ cells. It is anticipated that application of systems biology approaches will further our understanding of the regulatory mechanism of spermatogenesis.† PMID:19306351

  16. Ultrastructural and immunocytochemical characterization of ameloblast-enamel adhesion at maturation stage in amelogenesis in Macaca fuscata tooth germ.

    PubMed

    Sawada, Takashi

    2015-12-01

    Maturation-stage ameloblasts are firmly bound to the tooth enamel by a basal lamina-like structure. The mechanism underlying this adhesion, however, remains to be fully clarified. The goal of this study was to investigate the mechanism underlying adhesion between the basal lamina-like structure and the enamel in monkey tooth germ. High-resolution immunogold labeling was performed to localize amelotin and laminin 332 at the interface between ameloblasts and tooth enamel. Minute, electron-dense strands were observed on the enamel side of the lamina densa, extending into the degrading enamel matrix to produce a well-developed fibrous layer (lamina fibroreticularis). In un-demineralized tissue sections, mineral crystals smaller than those in the bulk of the enamel were observed adhering to these strands where they protruded into the surface enamel. Immunogold particles reactive for amelotin were preferentially localized on these strands in the fibrous layer. On the other hand, those for laminin 332 were localized solely in the lamina densa; none were observed in the fibrous layer. These results suggest that the fibrous layer of the basal lamina-like structure is partly composed of amelotin molecules, and that these molecules facilitate ameloblast-enamel adhesion by promoting mineralization of the fibrous layer during the maturation stage of amelogenesis.

  17. Bmp 2 and bmp 7 induce odonto- and osteogenesis of human tooth germ stem cells.

    PubMed

    Taşlı, P Neslihan; Aydın, Safa; Yalvaç, Mehmet Emir; Sahin, Fikrettin

    2014-03-01

    Bone morphogenetic proteins (BMPs) initiate, promote, and maintain odontogenesis and osteogenesis. In this study, we studied the effect of bone morphogenic protein 2 (BMP 2) and bone morphogenic protein 7 (BMP 7) as differentiation inducers in tooth and bone regeneration. We compared the effect of BMP 2 and BMP 7 on odontogenic and osteogenic differentiation of human tooth germ stem cells (hTGSCs). Third molar-derived hTGSCs were characterized with mesenchymal stem cell surface markers by flow cytometry. BMP 2 and BMP 7 were transfected into hTGSCs and the cells were seeded onto six-well plates. One day after the transfection, hTGSCs were treated with odontogenic and osteogenic mediums for 14 days. For confirmation of odontogenic and osteogenic differentiation, mRNA levels of BMP2, BMP 7, collagen type 1 (COL1A), osteocalsin (OCN), and dentin sialophosphoprotein (DSPP) genes were measured by quantitative real-time PCR. In addition to this, immunocytochemistry was performed by odontogenic and osteogenic antibodies and mineralization obtained by von Kossa staining. Our results showed that the BMP 2 and BMP 7 both promoted odontogenic and osteogenic differentiation of hTGSCs. Data indicated that BMP 2 treatment and BMP 7 treatment induce odontogenic differentiation without affecting each other, whereas they induce osteogenic differentiation by triggering expression of each other. These findings provide a feasible tool for tooth and bone tissue engineering.

  18. Gene Expression Profiling during Murine Tooth Development.

    PubMed

    Landin, Maria A Dos Santos Silva; Shabestari, Maziar; Babaie, Eshrat; Reseland, Janne E; Osmundsen, Harald

    2012-01-01

    The aim of this study was to describe the expression of genes, including ameloblastin (Ambn), amelogenin X chromosome (Amelx), and enamelin (Enam) during early (pre-secretory) tooth development. The expression of these genes has predominantly been studied at post-secretory stages. Deoxyoligonucleotide microarrays were used to study gene expression during development of the murine first molar tooth germ at 24 h intervals, starting at the 11th embryonic day (E11.5), and up to the 7th day after birth (P7). The profile search function of Spotfire software was used to select genes with similar expression profile as the enamel genes (Ambn, Amelx, and Enam). Microarray results where validated using real-time reverse transcription-polymerase chain reaction (real-time RT-PCR), and translated proteins identified by Western-blotting. In situ localization of the Ambn, Amelx, and Enam mRNAs were monitored from E12.5 to E17.5 using deoxyoligonucleotide probes. Bioinformatics analysis was used to associate biological functions with differentially expressed (DE; p ≤ 0.05) genes. Microarray results showed a total of 4362 genes including Ambn, Amelx, and Enam to be significant DE throughout the time-course. The expression of the three enamel genes was low at pre-natal stages (E11.5-P0) increasing after birth (P1-P7). Profile search lead to isolation of 87 genes with significantly similar expression to the three enamel proteins. These mRNAs were expressed in dental epithelium and epithelium derived cells. Although expression of Ambn, Amelx, and Enam were lower during early tooth development compared to secretory stages enamel proteins were detectable by Western-blotting. Bioinformatic analysis associated the 87 genes with multiple biological functions. Around 35 genes were associated with 15 transcription factors.

  19. Gene Expression Profiling during Murine Tooth Development

    PubMed Central

    Landin, Maria A. dos Santos Silva; Shabestari, Maziar; Babaie, Eshrat; Reseland, Janne E.; Osmundsen, Harald

    2012-01-01

    The aim of this study was to describe the expression of genes, including ameloblastin (Ambn), amelogenin X chromosome (Amelx), and enamelin (Enam) during early (pre-secretory) tooth development. The expression of these genes has predominantly been studied at post-secretory stages. Deoxyoligonucleotide microarrays were used to study gene expression during development of the murine first molar tooth germ at 24 h intervals, starting at the 11th embryonic day (E11.5), and up to the 7th day after birth (P7). The profile search function of Spotfire software was used to select genes with similar expression profile as the enamel genes (Ambn, Amelx, and Enam). Microarray results where validated using real-time reverse transcription-polymerase chain reaction (real-time RT-PCR), and translated proteins identified by Western-blotting. In situ localization of the Ambn, Amelx, and Enam mRNAs were monitored from E12.5 to E17.5 using deoxyoligonucleotide probes. Bioinformatics analysis was used to associate biological functions with differentially expressed (DE; p ≤ 0.05) genes. Microarray results showed a total of 4362 genes including Ambn, Amelx, and Enam to be significant DE throughout the time-course. The expression of the three enamel genes was low at pre-natal stages (E11.5–P0) increasing after birth (P1–P7). Profile search lead to isolation of 87 genes with significantly similar expression to the three enamel proteins. These mRNAs were expressed in dental epithelium and epithelium derived cells. Although expression of Ambn, Amelx, and Enam were lower during early tooth development compared to secretory stages enamel proteins were detectable by Western-blotting. Bioinformatic analysis associated the 87 genes with multiple biological functions. Around 35 genes were associated with 15 transcription factors. PMID:22866057

  20. Current knowledge of tooth development: patterning and mineralization of the murine dentition.

    PubMed

    Catón, Javier; Tucker, Abigail S

    2009-04-01

    The integument forms a number of different types of mineralized element, including dermal denticles, scutes, ganoid scales, elasmoid scales, fin rays and osteoderms found in certain fish, reptiles, amphibians and xenarthran mammals. To this list can be added teeth, which are far more widely represented and studied than any of the other mineralized elements mentioned above, and as such can be thought of as a model mineralized system. In recent years the focus for studies on tooth development has been the mouse, with a wealth of genetic information accrued and the availability of cutting edge techniques. It is the mouse dentition that this review will concentrate on. The development of the tooth will be followed, looking at what controls the shape of the tooth and how signals from the mesenchyme and epithelium interact to lead to formation of a molar or incisor. The number of teeth generated will then be investigated, looking at how tooth germ number can be reduced or increased by apoptosis, fusion of tooth germs, creation of new tooth germs, and the generation of additional teeth from existing tooth germs. The development of mineralized tissue will then be detailed, looking at how the asymmetrical deposition of enamel is controlled in the mouse incisor. The continued importance of epithelial-mesenchymal interactions at these later stages of tooth development will also be discussed. Tooth anomalies and human disorders have been well covered by recent reviews, therefore in this paper we wish to present a classical review of current knowledge of tooth development, fitting together data from a large number of recent research papers to draw general conclusions about tooth development.

  1. R-spondins/Lgrs expression in tooth development.

    PubMed

    Kawasaki, Maiko; Porntaveetus, Thantrira; Kawasaki, Katsushige; Oommen, Shelly; Otsuka-Tanaka, Yoko; Hishinuma, Mitsue; Nomoto, Takato; Maeda, Takeyasu; Takubo, Keiyo; Suda, Toshio; Sharpe, Paul T; Ohazama, Atsushi

    2014-06-01

    Tooth development is highly regulated in mammals and it is regulated by networks of signaling pathways (e. g. Tnf, Wnt, Shh, Fgf and Bmp) whose activities are controlled by the balance between ligands, activators, inhibitors and receptors. The members of the R-spondin family are known as activators of Wnt signaling, and Lgr4, Lgr5, and Lgr6 have been identified as receptors for R-spondins. The role of R-spondin/Lgr signaling in tooth development, however, remains unclear. We first carried out comparative in situ hybridization analysis of R-spondins and Lgrs, and identified their dynamic spatio-temporal expression in murine odontogenesis. R-spondin2 expression was found both in tooth germs and the tooth-less region, the diastema. We further examined tooth development in R-spondin2 mutant mice, and although molars and incisors exhibited no significant abnormalities, supernumerary teeth were observed in the diastema. R-spondin/Lgr signaling is thus involved in tooth development. © 2014 Wiley Periodicals, Inc.

  2. Evolutionary implications of the occurrence of two vestigial tooth germs during early odontogenesis in the mouse lower jaw.

    PubMed

    Viriot, Laurent; Peterková, Renata; Peterka, Miroslav; Lesot, Hervé

    2002-01-01

    The study of closely-spaced developmental stages reveals the occurrence of three distinct dental segments during early odontogenesis in the ICR mouse lower jaw: the mesial (MS), the second rudimentary (R2), and the molar segments. At embryonic day (ED) 12.5, the MS displays an accessory bud, which regresses rapidly and disappears at ED 13.5. The R2 segment reaches a wide bud stage at ED 13.5 and then merges with the mesial end of the emerging first lower molar (M1) cap before ED 15.0. The MS and R2 segments never develop into functional teeth and are classified as vestigial tooth germs. Depending on their developmental chronology and on the position they occupy along the prospective mandibular tooth row, MS and R2 segments are putatively assigned to primordia of a third (dP3) and fourth (dP4) lower deciduous premolar, respectively. Evolutionary implications of these developmental data are discussed.

  3. Epithelial histogenesis during tooth development.

    PubMed

    Lesot, H; Brook, A H

    2009-12-01

    This paper reviews the current understanding of the progressive changes mediating dental epithelial histogenesis as a basis for future collaborative studies. Tooth development involves morphogenesis, epithelial histogenesis and cell differentiation. The consecutive morphological stages of lamina, bud, cap and bell are also characterized by changes in epithelial histogenesis. Differential cell proliferation rates, apoptosis, and alterations in adhesion and shape lead to the positioning of groups of cells with different functions. During tooth histo-morphogenesis changes occur in basement membrane composition, expression of signalling molecules and the localization of cell surface components. Cell positional identity may be related to cell history. Another important parameter is cell plasticity. Independently of signalling molecules, which play a major role in inducing or modulating specific steps, cell-cell and cell-matrix interactions regulate the plasticity/rigidity of particular domains of the enamel organ. This involves specifying in space the differential growth and influences the progressive tooth morphogenesis by shaping the epithelial-mesenchymal junction. Deposition of a mineralized matrix determines the final shape of the crown. All data reviewed in this paper were investigated in the mouse.

  4. Opg, Rank, and Rankl in tooth development: co-ordination of odontogenesis and osteogenesis.

    PubMed

    Ohazama, A; Courtney, J-M; Sharpe, P T

    2004-03-01

    Osteoprotegerin (OPG), receptor activator of nuclear factor-kappaB (RANK), and RANK ligand (RANKL) are mediators of various cellular interactions, including bone metabolism. We analyzed expression of these three genes during murine odontogenesis from epithelial thickening to cytodifferentiation stages. Opg showed expression in the thickening and bud epithelium. Expression of Opg and Rank was observed in both the internal and the external enamel epithelium as well as in the dental papilla mesenchyme. Although Rankl expression was not detected in tooth epithelium or mesenchyme, it was expressed in pre-osteogenic mesenchymal cells close to developing tooth germs. All three genes were detected in developing dentary bone at P0. The addition of exogenous OPG to explant cultures of tooth primordia produced a delay in tooth development that resulted in reduced mineralization. We propose that the spatiotemporal expression of these molecules in early tooth and bone primordia cells has a role in co-ordinating bone and tooth development.

  5. Immunohistochemical expression of podoplanin (D2-40), lymphangiogenesis, and neoangiogenesis in tooth germ, ameloblastomas, and ameloblastic carcinomas.

    PubMed

    Sánchez-Romero, Celeste; Bologna-Molina, Ronell; Mosqueda-Taylor, Adalberto; de Almeida, Oslei Paes

    2017-09-01

    Ameloblastoma is a benign but locally aggressive odontogenic tumor, while ameloblastic carcinoma is its malignant counterpart. Angiogenesis and lymphangiogenesis in malignancies have been correlated with higher aggressiveness and poor prognosis, as well as greater expression of podoplanin by tumoral cells. Immunohistochemical expression of podoplanin, CD34, and CD105 (endoglin) was evaluated in 53 ameloblastomas and three ameloblastic carcinomas; additionally, immunohistochemistry for podoplanin was also performed in 10 tooth germs. Microvessel density of blood and lymphatic vessels was calculated and compared between ameloblastomas and ameloblastic carcinomas. Immunoexpression of podoplanin by ameloblastic cells was evaluated in tooth germs, ameloblastomas, and ameloblastic carcinomas. Podoplanin was similarly expressed by odontogenic epithelial cells of tooth germs and ameloblastomas, while its expression was lower in ameloblastic carcinomas. There was no difference in microvessel density assessed by CD34 between ameloblastomas and ameloblastic carcinomas; nevertheless, the latter presented higher amounts of lymphatic and new formed blood vessels. Results suggest that podoplanin does not seem to be involved in invasion mechanisms of ameloblastic carcinomas, as its expression was decreased in the malignant tumoral cells. On the other hand, the increased lymphatic microvessel density and neoangiogenesis found in ameloblastic carcinomas could be related to its aggressiveness and potential for metastasis. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  6. Characterization of dental pulp stem/stromal cells of Huntington monkey tooth germs.

    PubMed

    Snyder, Brooke R; Cheng, Pei-Hsun; Yang, Jinjing; Yang, Shang-Hsun; Huang, Anderson H C; Chan, Anthony W S

    2011-09-12

    Dental pulp stem/stromal cells (DPSCs) are categorized as adult stem cells (ASCs) that retain multipotent differentiation capabilities. DPSCs can be isolated from individuals at any age and are considered to be true personal stem cells, making DPSCs one of the potential options for stem cell therapy. However, the properties of DPSCs from individuals with an inherited genetic disorder, such as Huntington's disease (HD), have not been fully investigated. To examine if mutant huntingtin (htt) protein impacts DPSC properties, we have established DPSCs from tooth germ of transgenic monkeys that expressed both mutant htt and green fluorescent protein (GFP) genes (rHD/G-DPSCs), and from a monkey that expressed only the GFP gene (rG-DPSCs), which served as a control. Although mutant htt and oligomeric htt aggregates were overtly present in rHD/G-DPSCs, all rHD/G-DPSCs and rG-DPSCs shared similar characteristics, including self-renewal, multipotent differentiation capabilities, expression of stemness and differentiation markers, and cell surface antigen profile. Our results suggest that DPSCs from Huntington monkeys retain ASC properties. Thus DPSCs derived from individuals with genetic disorders such as HD could be a potential source of personal stem cells for therapeutic purposes.

  7. c-kit positive cells and networks in tooth germs of human midterm fetuses.

    PubMed

    Didilescu, Andreea Cristiana; Pop, Florinel; Rusu, Mugurel Constantin

    2013-12-01

    Numerous studies have attempted to characterize the dental pulp stem cells. However, studies performed on prenatal human tissues have not been performed to evaluate the in situ characterization and topography of progenitor cells. We aimed to perform such a study using of antibodies for CD117/c-kit and multiplex antibody for Ki67+ caspase 3. Antibodies were applied on samples dissected from five human midterm fetuses. Positive CD117/c-kit labeling was found in mesenchymal derived tissues, such as the dental follicle and the dental papilla. The epithelial tissues, that is, dental lamina, enamel organ and oral epithelia, also displayed isolated progenitor cells which were CD117/c-kit positive. Interestingly, CD117/c-kit positive cells of mesenchymal derived tissues extended multiple prolongations building networks; the most consistent of such networks were those of the dental follicle and the perivascular networks of the dental papilla. However, the mantle of the dental papilla was also positive for CD117/c-kit positive stromal networks. The CD117/c-kit cell populations building networks appeared mostly with a Ki67 negative phenotype. The results suggest that CD117/c-kit progenitor cells of the prenatal tooth germ tissues might be involved in intercellular signaling. Copyright © 2013 Elsevier GmbH. All rights reserved.

  8. Immunohistochemical Expression of GLUT-1 and HIF-1α in Tooth Germ, Ameloblastoma, and Ameloblastic Carcinoma.

    PubMed

    Sánchez-Romero, Celeste; Bologna-Molina, Ronell; Mosqueda-Taylor, Adalberto; Paes de Almeida, Oslei

    2016-08-01

    Hypoxia-inducible factor-1α (HIF-1α) promotes proteins that enable cell survival during hypoxia, such as glucose transporter 1 (GLUT-1). Their coexpression has been associated with aggressiveness in malignancies and has not been studied in odontogenic tumors. Immunohistochemical expression of HIF-1α and GLUT-1 was analyzed in 13 tooth germs (TGs), 55 ameloblastomas (AMs), and 3 ameloblastic carcinomas (ACs). HIF-1α was negative in all TGs, and just 1 case of AM and 1 of AC had nuclear positivity. GLUT-1 expressed in ameloblastic cells of all TGs, AMs, and ACs, with an increasing intensity, respectively, and was significantly higher in solid AM than in unicystic AM (P = .041). Absence of nuclear HIF-1α in TGs and most AMs suggest that GLUT-1 may be induced by alternative pathways to hypoxia. However, in ACs, HIF-1α may be activated; however, to confirm this, additional cases are needed. GLUT-1 overexpression could be related to aggressiveness in AMs and ACs and must represent a normal metabolite in TGs. © The Author(s) 2016.

  9. Effect of F68 on cryopreservation of mesenchymal stem cells derived from human tooth germ.

    PubMed

    Doğan, Ayşegül; Yalvaç, Mehmet Emir; Yılmaz, Aysu; Rizvanov, Albert; Sahin, Fikrettin

    2013-12-01

    The use of stem-cell-based therapies in regenerative medicine and in the treatment of disorders such as Parkinson, Alzheimer's disease, diabetes, spinal cord injuries, and cancer has been shown to be promising. Among all stem cells, mesenchymal stem cells (MSCs) were reported to have anti-apoptotic, immunomodulatory, and angiogenic effects which are attributed to the restorative capacity of these cells. Human tooth germ stem cells (HTGSCs) having mesenchymal stem cell characteristics have been proven to exert high proliferation and differentiation capacity. Unlike bone-marrow-derived MSCs, HTGSCs can be easily isolated, expanded, and cryopreserved, which makes them an alternative stem cell source. Regardless of their sources, the stem cells are exposed to physical and chemical stresses during cryopreservation, hindering their therapeutic capacity. Amelioration of the side effects of cryopreservation on MSCs seems to be a priority in order to maximize the therapeutic efficacy of these cells. In this study, we tested the effect of Pluronic 188 (F68) on HTGSCs during long-term cryopreservation and repeated freezing and defrosting cycles. Our data revealed that F68 has a protective role on survival and differentiation of HTGSCs in long-term cryopreservation.

  10. Expression patterns of WNT/β-CATENIN signaling molecules during human tooth development.

    PubMed

    Wang, Bingmei; Li, Hanliang; Liu, Ying; Lin, Xin; Lin, Yao; Wang, Ye; Hu, Xuefeng; Zhang, Yanding

    2014-10-01

    The WNT/β-CATENIN signaling has been demonstrated to play critical roles in mouse tooth development, but little is known about the status of these molecules in human embryonic tooth. In this study, expression patterns of WNT/β-CATENIN signaling components, including WNT ligands (WNT3, WNT5A), receptors (FZD4, FZD6, LRP5), transducers (β-CATENIN), transcription factors (TCF4, LEF1) and antagonists (DKK1, SOSTDC1) were investigated in human tooth germ at the bud, cap and bell stages by in situ hybridization. All these genes exhibited similar but slightly distinct expression patterns in human tooth germ in comparison with mouse. Furthermore the mRNA expression of these genes in incisors and molars at the bell stage was also examined by real-time PCR. Our results reveal the status of active WNT/β-CATENIN signaling in the human tooth germ and suggest these components may also play an essential role in the regulation of human tooth development.

  11. On the development of extragonadal and gonadal human germ cells.

    PubMed

    Heeren, A Marijne; He, Nannan; de Souza, Aline F; Goercharn-Ramlal, Angelique; van Iperen, Liesbeth; Roost, Matthias S; Gomes Fernandes, Maria M; van der Westerlaken, Lucette A J; Chuva de Sousa Lopes, Susana M

    2016-02-01

    Human germ cells originate in an extragonadal location and have to migrate to colonize the gonadal primordia at around seven weeks of gestation (W7, or five weeks post conception). Many germ cells are lost along the way and should enter apoptosis, but some escape and can give rise to extragonadal germ cell tumors. Due to the common somatic origin of gonads and adrenal cortex, we investigated whether ectopic germ cells were present in the human adrenals. Germ cells expressing DDX4 and/or POU5F1 were present in male and female human adrenals in the first and second trimester. However, in contrast to what has been described in mice, where 'adrenal' and 'ovarian' germ cells seem to enter meiosis in synchrony, we were unable to observe meiotic entry in human 'adrenal' germ cells until W22. By contrast, 'ovarian' germ cells at W22 showed a pronounced asynchronous meiotic entry. Interestingly, we observed that immature POU5F1+ germ cells in both first and second trimester ovaries still expressed the neural crest marker TUBB3, reminiscent of their migratory phase. Our findings highlight species-specific differences in early gametogenesis between mice and humans. We report the presence of a population of ectopic germ cells in the human adrenals during development. © 2016. Published by The Company of Biologists Ltd.

  12. On the development of extragonadal and gonadal human germ cells

    PubMed Central

    Heeren, A. Marijne; He, Nannan; de Souza, Aline F.; Goercharn-Ramlal, Angelique; van Iperen, Liesbeth; Roost, Matthias S.; Gomes Fernandes, Maria M.; van der Westerlaken, Lucette A. J.; Chuva de Sousa Lopes, Susana M.

    2016-01-01

    ABSTRACT Human germ cells originate in an extragonadal location and have to migrate to colonize the gonadal primordia at around seven weeks of gestation (W7, or five weeks post conception). Many germ cells are lost along the way and should enter apoptosis, but some escape and can give rise to extragonadal germ cell tumors. Due to the common somatic origin of gonads and adrenal cortex, we investigated whether ectopic germ cells were present in the human adrenals. Germ cells expressing DDX4 and/or POU5F1 were present in male and female human adrenals in the first and second trimester. However, in contrast to what has been described in mice, where ‘adrenal’ and ‘ovarian’ germ cells seem to enter meiosis in synchrony, we were unable to observe meiotic entry in human ‘adrenal’ germ cells until W22. By contrast, ‘ovarian’ germ cells at W22 showed a pronounced asynchronous meiotic entry. Interestingly, we observed that immature POU5F1+ germ cells in both first and second trimester ovaries still expressed the neural crest marker TUBB3, reminiscent of their migratory phase. Our findings highlight species-specific differences in early gametogenesis between mice and humans. We report the presence of a population of ectopic germ cells in the human adrenals during development. PMID:26834021

  13. Neonatal line as a linear evidence of live birth: Estimation of postnatal survival of a new born from primary tooth germs.

    PubMed

    Janardhanan, Mahija; Umadethan, B; Biniraj, Kr; Kumar, Rb Vinod; Rakesh, S

    2011-01-01

    The presence of neonatal line indicates live birth and it is possible to estimate the exact period of survival of the infant in days by measuring the amount of postnatal hard tissue formation, and thus can be an evidence to the brutal act of infanticide. Primary tooth germs of both the arches were removed from the sockets of an infant who died few days after birth. Ground sections were made with hard tissue microtome. Decalcified sections were made from the crown of primary right mandibular canine and the sections were stained with hematoxylin and eosin. To visualize the neonatal line, the sections were subjected to light mocroscopy, polarized microscopy and scanning electron microscopy. A developing permanent molar from a one and a half year old boy and ten fully developed deciduous molars were used as controls. The ground sections of all the developing tooth germs showed the presence of neonatal line and the analysis of enamel showed six distinct cross striations along the enamel rod length indicating the period of survival of the baby to be six days which was later confirmed with the hospital records. Neonatal line could be used as an evidence of infanticide. Accurate detection of neonatal line with advanced techniques could rewrite this supplementary evidence of infanticide into substantial evidence.

  14. Tissue Interactions Regulating Tooth Development and Renewal.

    PubMed

    Balic, Anamaria; Thesleff, Irma

    2015-01-01

    Reciprocal interactions between epithelial and mesenchymal tissues play a fundamental role in the morphogenesis of teeth and regulate all aspects of tooth development. Extensive studies on mouse tooth development over the past 25 years have uncovered the molecular details of the signaling networks mediating these interactions (reviewed by Jussila & Thesleff, 2012; Lan, Jia, & Jiang, 2014). Five conserved signaling pathways, namely, the Wnt, BMP, FGF, Shh, and Eda, are involved in the mediation of the successive reciprocal epithelial-mesenchymal cross talk which follows the general principle of morphogenetic interactions (Davidson, 1993). The pathways regulate the expression of transcription factors which confer the identity of dental epithelium and mesenchyme. The signals and transcription factors are integrated in complex signaling networks whose fine-tuning allows the generation of the variation in tooth morphologies. In this review, we describe the principles and molecular mechanisms of the epithelial-mesenchymal interactions regulating successive stages of tooth formation: (i) the initiation of tooth development, with special reference to the shift of tooth-forming potential from epithelium to mesenchyme; (ii) the morphogenesis of the tooth crown, focusing on the roles of epithelial signaling centers; (iii) the differentiation of odontoblasts and ameloblasts, which produce dentin and enamel, respectively; and (iv) the maintenance of dental stem cells, which support the continuous growth of teeth. © 2015 Elsevier Inc. All rights reserved.

  15. Coordination of tooth morphogenesis and neuronal development through tissue interactions: lessons from mouse models.

    PubMed

    Luukko, Keijo; Kettunen, Päivi

    2014-07-15

    In addition to being an advantageous model to investigate general molecular mechanisms of organ formation, the tooth is a distinct target organ for peripheral nerve innervation. These nerves are required for the function and protection of the teeth and, as shown in fish, also for their regeneration. This review focuses on recent findings of the local tissue interactions and molecular signaling mechanisms that regulate the early nerve arrival and patterning of mouse mandibular molar tooth sensory innervation. Dental sensory nerve growth and patterning is a stepwise process that is intimately linked to advancing tooth morphogenesis. In particular, nerve growth factor and semaphorin 3A serve as essential functions during and are iteratively used at different stages of tooth innervation. The tooth germ controls development of its own nerve supply, and similar to the development of the tooth organ proper, tissue interactions between dental epithelial and mesenchymal tissues control the establishment of tooth innervation. Tgf-β, Wnt, and Fgf signaling, which regulate tooth formation, are implicated to mediate these interactions. Therefore, tissue interactions mediated by conserved signal families may constitute key mechanism for the integration of tooth organogenesis and development of its peripheral nerve supply. Copyright © 2014 Elsevier Inc. All rights reserved.

  16. Human tooth germ stem cell response to calcium-silicate based endodontic cements

    PubMed Central

    PAMUKÇU GÜVEN, Esra; YALVAÇ, Mehmet Emir; KAYAHAN, Mehmet Baybora; SUNAY, Hakkı; ŞAHİN, Fikrettin; BAYIRLI, Gündüz

    2013-01-01

    Objective The aim of this study was to compare the cytotoxic effects of endodontic cements on human tooth germ stem cells (hTGSCs). MTA Fillapex, a mineral trioxide aggregate (MTA)-based, salicylate resin containing root canal sealer, was compared with iRoot SP, a bioceramic sealer, and AH Plus Jet, an epoxy resin-based root canal sealer. Material and Methods To evaluate cytotoxicity, all materials were packed into Teflon rings (4 mmµ3 mm) and co-cultured with hTGSCs with the aid of 24-well Transwell permeable supports, which had a pore size of 0.4 µm. Coverslips were coated with MTA Fillapex, iRoot SP and AH Plus Jet and each coverslip was placed onto the bottom of one well of a six-well plate for scanning electron microscopy (SEM) analysis. Before the cytotoxicity and SEM analysis, all samples were stored at 37ºC and at 95% humidity and 5% CO2 for 24 hours to set. The cellular viability was analyzed using MTS test (3-(4,5-dimethyl-thiazol-2-yl)-5-(3-carboxy-methoxy-phenyl)-2-(4-sulfo-phenyl)-2H-tetrazolium). The cytotoxic effects and SEM visualization of the tested materials were analyzed at 24-hour, 72-hour, one-week and two-week periods. Results On the 1st day, only MTA Fillapex caused cytotoxicity compared to negative control (NC) group (p<0.008). No significant difference was observed between the other tested materials at this period (p>0.05). After 14 days of incubation with the test materials, MTA Fillapex exhibited significantly higher cytotoxicity compared with iRoot SP, AH Plus Jet and the NC group (P<0.008). In the SEM analysis, the highest levels of cell attachment were observed for iRoot SP and the control group. After 24 hours, MTA Fillapex reduced the number of cells attached to the surface. Conclusions Within the limitations of this study, sealers exerted different cytotoxic effects on hTGSCs. Although all materials have exerted cellular toxicity, iRoot SP and AH Plus Jet may promote better attachment to hTGSCs. PMID:24037075

  17. Morphological study of tooth development in podoplanin-deficient mice

    PubMed Central

    Takara, Kenyo; Maruo, Naoki; Oka, Kyoko; Kaji, Chiaki; Hatakeyama, Yuji; Sawa, Naruhiko; Kato, Yukinari; Yamashita, Junro; Kojima, Hiroshi; Sawa, Yoshihiko

    2017-01-01

    Podoplanin is a mucin-type highly O-glycosylated glycoprotein identified in several somatyic cells: podocytes, alveolar epithelial cells, lymphatic endothelial cells, lymph node stromal fibroblastic reticular cells, osteocytes, odontoblasts, mesothelial cells, glia cells, and others. It has been reported that podoplanin-RhoA interaction induces cytoskeleton relaxation and cell process stretching in fibroblastic cells and osteocytes, and that podoplanin plays a critical role in type I alveolar cell differentiation. It appears that podoplanin plays a number of different roles in contributing to cell functioning and growth by signaling. However, little is known about the functions of podoplanin in the somatic cells of the adult organism because an absence of podoplanin is lethal at birth by the respiratory failure. In this report, we investigated the tooth germ development in podoplanin-knockout mice, and the dentin formation in podoplanin-conditional knockout mice having neural crest-derived cells with deficiency in podoplanin by the Wnt1 promoter and enhancer-driven Cre recombinase: Wnt1-Cre;PdpnΔ/Δmice. In the Wnt1-Cre;PdpnΔ/Δmice, the tooth and alveolar bone showed no morphological abnormalities and grow normally, indicating that podoplanin is not critical in the development of the tooth and bone. PMID:28222099

  18. Morphological study of tooth development in podoplanin-deficient mice.

    PubMed

    Takara, Kenyo; Maruo, Naoki; Oka, Kyoko; Kaji, Chiaki; Hatakeyama, Yuji; Sawa, Naruhiko; Kato, Yukinari; Yamashita, Junro; Kojima, Hiroshi; Sawa, Yoshihiko

    2017-01-01

    Podoplanin is a mucin-type highly O-glycosylated glycoprotein identified in several somatyic cells: podocytes, alveolar epithelial cells, lymphatic endothelial cells, lymph node stromal fibroblastic reticular cells, osteocytes, odontoblasts, mesothelial cells, glia cells, and others. It has been reported that podoplanin-RhoA interaction induces cytoskeleton relaxation and cell process stretching in fibroblastic cells and osteocytes, and that podoplanin plays a critical role in type I alveolar cell differentiation. It appears that podoplanin plays a number of different roles in contributing to cell functioning and growth by signaling. However, little is known about the functions of podoplanin in the somatic cells of the adult organism because an absence of podoplanin is lethal at birth by the respiratory failure. In this report, we investigated the tooth germ development in podoplanin-knockout mice, and the dentin formation in podoplanin-conditional knockout mice having neural crest-derived cells with deficiency in podoplanin by the Wnt1 promoter and enhancer-driven Cre recombinase: Wnt1-Cre;PdpnΔ/Δmice. In the Wnt1-Cre;PdpnΔ/Δmice, the tooth and alveolar bone showed no morphological abnormalities and grow normally, indicating that podoplanin is not critical in the development of the tooth and bone.

  19. (/sup 35/S)autoradiographic study of sulfated GAG accumulation and turnover in embryonic mouse tooth germs

    SciTech Connect

    Lau, E.C.; Boukari, A.; Arechaga, J.; Osman, M.; Ruch, J.V.

    1983-01-01

    The accumulation of sulfated glycosaminoglycans(GAG) in embryonic mouse molars before, during, and after terminal differentiation of odontoblasts was localized by (/sup 35/S)autoradiography combined with the use of chondroitin ABC lyase. Much more sulfated GAG were accumulated in the dental papilla than in the dental epithelium. High incorporation of (/sup 35/S)sulfate occurred at the epithelio-mesenchymal junction, which is the site of dental basement membrane and predentin. Before terminal differentiation of odontoblasts, the distribution of sulfated GAG was uniform at the basement membrane. After the onset of terminal differentiation of odontoblasts, much more sulfated GAG accumulated at the tip of principal cusps than at the apical (inferior) parts of cusps, and sulfated GAG were then found to be degraded more rapidly at the epithelio-mesenchymal junction than at other parts of the tooth germ. Thus regional variation in the rate of degradation of GAG exists in the tooth germs. Trypsin-isolated dental epithelia cultured in vitro synthesized a new basement membrane that could be labeled with (/sup 3/H)glucosamine but not with /sup 35/SO4(-2). The epithelial-derived basal lamina contains little or no sulfatated GAG.

  20. Origin and development of the germ line in sea stars.

    PubMed

    Wessel, Gary M; Fresques, Tara; Kiyomoto, Masato; Yajima, Mamiko; Zazueta, Vanesa

    2014-05-01

    This review summarizes and integrates our current understanding of how sea stars make gametes. Although little is known of the mechanism of germ line formation in these animals, recent results point to specific cells and to cohorts of molecules in the embryos and larvae that may lay the ground work for future research efforts. A coelomic outpocketing forms in the posterior of the gut in larvae, referred to as the posterior enterocoel (PE), that when removed, significantly reduces the number of germ cell later in larval growth. This same PE structure also selectively accumulates several germ-line associated factors-vasa, nanos, piwi-and excludes factors involved in somatic cell fate. Since its formation is relatively late in development, these germ cells may form by inductive mechanisms. When integrated into the morphological observations of germ cells and gonad development in larvae, juveniles, and adults, the field of germ line determination appears to have a good model system to study inductive germ line determination to complement the recent work on the molecular mechanisms in mice. We hope this review will also guide investigators interested in germ line determination and regulation of the germ line into how these animals can help in this research field. The review is not intended to be comprehensive-sea star reproduction has been studied for over 100 years and many reviews are comprehensive in their coverage of, for example, seasonal growth of the gonads in response to light, nutrient, and temperature. Rather the intent of this review is to help the reader focus on new experimental results attached to the historical underpinnings of how the germ cell functions in sea stars with particular emphasis to clarify the important areas of priority for future research. © 2014 Wiley Periodicals, Inc.

  1. Origin and development of the germ line in sea stars

    PubMed Central

    Wessel, Gary M.; Fresques, Tara; Kiyomoto, Masato; Yajima, Mamiko; Zazueta, Vanesa

    2014-01-01

    This review summarizes and integrates our current understanding of how sea stars make gametes. Although little is known of the mechanism of germ line formation in these animals, recent results point to specific cells and to cohorts of molecules in the embryos and larvae that may lay the ground work for future research efforts. A coelomic outpocketing forms in the posterior of the gut in larvae, referred to as the posterior enterocoel (PE), that when removed, significantly reduces the number of germ cell later in larval growth. This same PE structure also selectively accumulates several germ-line associated factors – vasa, nanos, piwi – and excludes factors involved in somatic cell fate. Since its formation is relatively late in development, these germ cells may form by inductive mechanisms. When integrated into the morphological observations of germ cells and gonad development in larvae, juveniles, and adults, the field of germ line determination appears to have a good model system to study inductive germ line determination to complement the recent work on the molecular mechanisms in mice. We hope this review will also guide investigators interested in germ line determination and regulation of the germ line in how these animals can help in this research field. The review is not intended to be comprehensive – sea star reproduction has been studied over 100 years and many reviews are comprehensive in their coverage of, for example, seasonal growth of the gonads in response to light, nutrient, and temperature. Rather the intent of this review is to help the reader focus on new experimental results attached to the historical underpinnings of how the germ cell functions in sea stars with particular emphasis to clarify the important areas of priority for future research. PMID:24648114

  2. Differential expression of decorin and biglycan genes during mouse tooth development

    NASA Technical Reports Server (NTRS)

    Matsuura, T.; Duarte, W. R.; Cheng, H.; Uzawa, K.; Yamauchi, M.

    2001-01-01

    Small leucine-rich proteoglycans (SLRPs) have a number of biological functions and some of them are thought to regulate collagen mineralizaton in bone and tooth. We have previously identified and immunolocalized two members of the SLRPs family, decorin and biglycan, in bovine tooth/periodontium. To investigate their potential roles in tooth development, we examined the mRNA expression patterns of decorin, biglycan and type I collagen in newborn (day 19) mice tooth germs by in situ hybridization. At this developmental stage, the first maxillary and mandibular molars include stages before and after secretion of the predentin matrix, respectively. The expression of decorin mRNA coincided with that of type I collagen mRNA and was mostly observed in secretory odontoblasts, while the biglycan mRNA was expressed throughout the tooth germ, including pre-secretory odontoblasts/ameloblasts, dental papilla and stellate reticulum. However, its signal in secretory odontoblasts was not as evident as that of decorin. In mandibular incisors, where a significant amount of predentin matrix and a small amount of enamel matrix were already secreted, a similar differential expression pattern was observed. In secretory ameloblasts the biglycan mRNA expression was apparent, while that of decorin was not. These differential expression patterns suggest the distinct roles of biglycan and decorin in the process of tooth development.

  3. Differential expression of decorin and biglycan genes during mouse tooth development

    NASA Technical Reports Server (NTRS)

    Matsuura, T.; Duarte, W. R.; Cheng, H.; Uzawa, K.; Yamauchi, M.

    2001-01-01

    Small leucine-rich proteoglycans (SLRPs) have a number of biological functions and some of them are thought to regulate collagen mineralizaton in bone and tooth. We have previously identified and immunolocalized two members of the SLRPs family, decorin and biglycan, in bovine tooth/periodontium. To investigate their potential roles in tooth development, we examined the mRNA expression patterns of decorin, biglycan and type I collagen in newborn (day 19) mice tooth germs by in situ hybridization. At this developmental stage, the first maxillary and mandibular molars include stages before and after secretion of the predentin matrix, respectively. The expression of decorin mRNA coincided with that of type I collagen mRNA and was mostly observed in secretory odontoblasts, while the biglycan mRNA was expressed throughout the tooth germ, including pre-secretory odontoblasts/ameloblasts, dental papilla and stellate reticulum. However, its signal in secretory odontoblasts was not as evident as that of decorin. In mandibular incisors, where a significant amount of predentin matrix and a small amount of enamel matrix were already secreted, a similar differential expression pattern was observed. In secretory ameloblasts the biglycan mRNA expression was apparent, while that of decorin was not. These differential expression patterns suggest the distinct roles of biglycan and decorin in the process of tooth development.

  4. Meiosis and retrotransposon silencing during germ cell development in mice.

    PubMed

    Ollinger, Rupert; Reichmann, Judith; Adams, Ian R

    2010-03-01

    In mammals, germ cells derive from the pluripotent cells that are present early in embryogenesis, and then differentiate into male sperm or female eggs as development proceeds. Fusion between an egg and a sperm at fertilization allows genetic information from both parents to be transmitted to the next generation, and produces a pluripotent zygote to initiate the next round of embryogenesis. Meiosis is a central event in this self-perpetuating cycle that creates genetic diversity by generating new combinations of existing genetic alleles, and halves the number of chromosomes in the developing male and female germ cells to allow chromosome number to be maintained through successive generations. The developing germ cells also help to maintain genetic and chromosomal stability through the generations by protecting the genome from excessive de novo mutation. Several mouse mutants have recently been characterised whose germ cells exhibit defects in silencing the potentially mutagenic endogenous retroviruses and other retrotransposons that are prevalent in mammalian genomes, and these germ cells also exhibit defects in progression through meiosis. Here we review how mouse germ cells develop and proceed through meiosis, how mouse germ cells silence endogenous retroviruses and other retrotransposons, and discuss why silencing of endogenous retroviruses and other retrotransposons may be required for meiotic progression in mice.

  5. Hedgehog signaling is required at multiple stages of zebrafish tooth development

    PubMed Central

    2010-01-01

    Background The accessibility of the developing zebrafish pharyngeal dentition makes it an advantageous system in which to study many aspects of tooth development from early initiation to late morphogenesis. In mammals, hedgehog signaling is known to be essential for multiple stages of odontogenesis; however, potential roles for the pathway during initiation of tooth development or in later morphogenesis are incompletely understood. Results We have identified mRNA expression of the hedgehog ligands shha and the receptors ptc1 and ptc2 during zebrafish pharyngeal tooth development. We looked for, but did not detect, tooth germ expression of the other known zebrafish hedgehog ligands shhb, dhh, ihha, or ihhb, suggesting that as in mammals, only Shh participates in zebrafish tooth development. Supporting this idea, we found that morphological and gene expression evidence of tooth initiation is eliminated in shha mutant embryos, and that morpholino antisense oligonucleotide knockdown of shha, but not shhb, function prevents mature tooth formation. Hedgehog pathway inhibition with the antagonist compound cyclopamine affected tooth formation at each stage in which we applied it: arresting development at early stages and disrupting mature tooth morphology when applied later. These results suggest that hedgehog signaling is required continuously during odontogenesis. In contrast, over-expression of shha had no effect on the developing dentition, possibly because shha is normally extensively expressed in the zebrafish pharyngeal region. Conclusion We have identified previously unknown requirements for hedgehog signaling for early tooth initiation and later morphogenesis. The similarity of our results with data from mouse and other vertebrates suggests that despite gene duplication and changes in the location of where teeth form, the roles of hedgehog signaling in tooth development have been largely conserved during evolution. PMID:21118524

  6. Hedgehog signaling is required at multiple stages of zebrafish tooth development.

    PubMed

    Jackman, William R; Yoo, James J; Stock, David W

    2010-11-30

    The accessibility of the developing zebrafish pharyngeal dentition makes it an advantageous system in which to study many aspects of tooth development from early initiation to late morphogenesis. In mammals, hedgehog signaling is known to be essential for multiple stages of odontogenesis; however, potential roles for the pathway during initiation of tooth development or in later morphogenesis are incompletely understood. We have identified mRNA expression of the hedgehog ligands shha and the receptors ptc1 and ptc2 during zebrafish pharyngeal tooth development. We looked for, but did not detect, tooth germ expression of the other known zebrafish hedgehog ligands shhb, dhh, ihha, or ihhb, suggesting that as in mammals, only Shh participates in zebrafish tooth development. Supporting this idea, we found that morphological and gene expression evidence of tooth initiation is eliminated in shha mutant embryos, and that morpholino antisense oligonucleotide knockdown of shha, but not shhb, function prevents mature tooth formation. Hedgehog pathway inhibition with the antagonist compound cyclopamine affected tooth formation at each stage in which we applied it: arresting development at early stages and disrupting mature tooth morphology when applied later. These results suggest that hedgehog signaling is required continuously during odontogenesis. In contrast, over-expression of shha had no effect on the developing dentition, possibly because shha is normally extensively expressed in the zebrafish pharyngeal region. We have identified previously unknown requirements for hedgehog signaling for early tooth initiation and later morphogenesis. The similarity of our results with data from mouse and other vertebrates suggests that despite gene duplication and changes in the location of where teeth form, the roles of hedgehog signaling in tooth development have been largely conserved during evolution.

  7. Epigenetic transitions in germ cell development and meiosis.

    PubMed

    Kota, Satya K; Feil, Robert

    2010-11-16

    Germ cell development is controlled by unique gene expression programs and involves epigenetic reprogramming of histone modifications and DNA methylation. The central event is meiosis, during which homologous chromosomes pair and recombine, processes that involve histone alterations. At unpaired regions, chromatin is repressed by meiotic silencing. After meiosis, male germ cells undergo chromatin remodeling, including histone-to-protamine replacement. Male and female germ cells are also differentially marked by parental imprints, which contribute to sex determination in insects and mediate genomic imprinting in mammals. Here, we review epigenetic transitions during gametogenesis and discuss novel insights from animal and human studies.

  8. Development, differentiation and manipulation of chicken germ cells.

    PubMed

    Nakamura, Yoshiaki; Kagami, Hiroshi; Tagami, Takahiro

    2013-01-01

    Germ cells are the only cell type capable of transmitting genetic information to the next generation. During development, they are set aside from all somatic cells of the embryo. In many species, germ cells form at the fringe of the embryo proper and then traverse through several developing somatic tissues on their migration to the emerging gonads. Primordial germ cells (PGCs) are the only cells in developing embryos with the potential to transmit genetic information to the next generation. Unlike other species, in avian embryos, PGCs use blood circulation for transport to the future gonadal region. This unique accessibility of avian PGCs during early development provides an opportunity to collect and transplant PGCs. The recent development of methods for production of germline chimeras by transfer of PGCs, and long-term cultivation methods of chicken PGCs without losing their germline transmission ability have provided important breakthroughs for the preservation of germplasm , for the production of transgenic birds and study the germ cell system. This review will describe the development, migration, differentiation and manipulation of germ cells, and discuss the prospects that germ cell technologies offer for agriculture, biotechnology and academic research. © 2013 The Authors Development, Growth & Differentiation © 2013 Japanese Society of Developmental Biologists.

  9. Control of male germ-cell development in flowering plants.

    PubMed

    Singh, Mohan B; Bhalla, Prem L

    2007-11-01

    Plant reproduction is vital for species survival, and is also central to the production of food for human consumption. Seeds result from the successful fertilization of male and female gametes, but our understanding of the development, differentiation of gamete lineages and fertilization processes in higher plants is limited. Germ cells in animals diverge from somatic cells early in embryo development, whereas plants have distinct vegetative and reproductive phases in which gametes are formed from somatic cells after the plant has made the transition to flowering and the formation of the reproductive organs. Recently, novel insights into the molecular mechanisms underlying male germ-line initiation and male gamete development in plants have been obtained. Transcriptional repression of male germ-line genes in non-male germ-line cells have been identified as a key mechanism for spatial and temporal control of male germ-line development. This review focuses on molecular events controlling male germ-line development especially, on the nature and regulation of gene expression programs operating in male gametes of flowering plants.

  10. Topology of the germ plasm and development of primordial germ cells in inverted amphibian eggs

    NASA Technical Reports Server (NTRS)

    Wakahara, M.; Neff, A. W.; Malacinski, G. M.

    1984-01-01

    Inverted Xenopus eggs have reduced numbers of primordial germ cells (PGCs). The extent of the reduction varies from spawning to spawning. Histologic examination revealed that PGC counts were lowest in inverted eggs which displayed the greatest amount of shift in the vegetal mass of large yolk platelets, although the germ plasm itself always remained localized in the egg's original vegetal hemisphere. Even at blastulation the germ plasm continued to be localized in the egg's original vegetal hemisphere. In many cases, however, it was confined to the periphery of the embryo, which probably accounts for the reduced PGC number in some tadpoles. In other cases it may have been dispersed and therefore not detectable in histologic analyses. Although the altered site of involution in inverted embryos did not influence PGC development, subsequent cell movement patterns apparently did. Those embryos which displayed the largest degree of pattern reversal at the tail-bud stage also exhibited the most extreme reduction in PGC numbers. A brief cold shock (4 degrees C, 10 min) prior to first cleavage leads to a further reduction in PGC numbers in inverted embryos, probably as a result of the displacement of the germ plasm away from its original vegetal pole location.

  11. Topology of the germ plasm and development of primordial germ cells in inverted amphibian eggs

    NASA Technical Reports Server (NTRS)

    Wakahara, M.; Neff, A. W.; Malacinski, G. M.

    1984-01-01

    Inverted Xenopus eggs have reduced numbers of primordial germ cells (PGCs). The extent of the reduction varies from spawning to spawning. Histologic examination revealed that PGC counts were lowest in inverted eggs which displayed the greatest amount of shift in the vegetal mass of large yolk platelets, although the germ plasm itself always remained localized in the egg's original vegetal hemisphere. Even at blastulation the germ plasm continued to be localized in the egg's original vegetal hemisphere. In many cases, however, it was confined to the periphery of the embryo, which probably accounts for the reduced PGC number in some tadpoles. In other cases it may have been dispersed and therefore not detectable in histologic analyses. Although the altered site of involution in inverted embryos did not influence PGC development, subsequent cell movement patterns apparently did. Those embryos which displayed the largest degree of pattern reversal at the tail-bud stage also exhibited the most extreme reduction in PGC numbers. A brief cold shock (4 degrees C, 10 min) prior to first cleavage leads to a further reduction in PGC numbers in inverted embryos, probably as a result of the displacement of the germ plasm away from its original vegetal pole location.

  12. Functional tooth regenerative therapy: tooth tissue regeneration and whole-tooth replacement.

    PubMed

    Oshima, Masamitsu; Tsuji, Takashi

    2014-07-01

    Oral and general health is compromised by irreversible dental problems, including dental caries, periodontal disease and tooth injury. Regenerative therapy for tooth tissue repair and whole-tooth replacement is currently considered a novel therapeutic concept with the potential for the full recovery of tooth function. Several types of stem cells and cell-activating cytokines have been identified in oral tissues. These cells are thought to be candidate cell sources for tooth tissue regenerative therapies because they have the ability to differentiate into tooth tissues in vitro and in vivo. Whole-tooth replacement therapy is regarded as an important model for the development of an organ regenerative concept. A novel three-dimensional cell-manipulation method, designated the organ germ method, has been developed to recapitulate organogenesis. This method involves compartmentalisation of epithelial and mesenchymal cells at a high cell density to mimic multicellular assembly conditions and epithelial-mesenchymal interactions. A bioengineered tooth germ can generate a structurally correct tooth in vitro and erupt successfully with the correct tooth structure when transplanted into the oral cavity. We have ectopically generated a bioengineered tooth unit composed of a mature tooth, periodontal ligament and alveolar bone, and that tooth unit was successfully engrafted into an adult jawbone through bone integration. Such bioengineered teeth were able to perform normal physiological tooth functions, such as developing a masticatory potential in response to mechanical stress and a perceptive potential for noxious stimuli. In this review, we describe recent findings and technologies underpinning tooth regenerative therapy.

  13. Tooth Decay

    MedlinePlus

    You call it a cavity. Your dentist calls it tooth decay or dental caries. They're all names for a hole in your tooth. The cause of tooth decay is plaque, a sticky substance in your mouth made up mostly of germs. Tooth decay starts in the outer layer, called the enamel. Without ...

  14. Dynamic expression of Six family genes in the dental mesenchyme and the epithelial ameloblast stem/progenitor cells during murine tooth development.

    PubMed

    Nonomura, Koji; Takahashi, Masanori; Wakamatsu, Yoshio; Takano-Yamamoto, Teruko; Osumi, Noriko

    2010-01-01

    Six family transcription factor genes play multiple and crucial roles in the development of the vertebrate sensory system including the eye, olfactory epithelium and otic vesicle, and these genes are highly expressed in the neural crest-derived cranial mesenchymal cells in the mouse embryo. However, expression patterns have yet to be determined for the Six family genes in the developing tooth germ. In this study, we examined expression of six members of the Six family genes in the dental mesenchyme and the dental epithelium of the developing tooth germs in mice by in situ hybridization. We found dynamic expression patterns for Six1, Six2, Six4 and Six5 in the oral epithelium and mesenchymal cells with distinct expression patterns at the early stage before invagination of the dental epithelium. In addition, expression of Six1 and Six4 was observed in the inner enamel epithelium of the incisor and molar tooth germs at the cap stage. Expression of Six5 was maintained in the bell stage tooth germs, and intense expression of Six1 and Six4 was detected not only in the mesenchyme-derived dental follicle but also in the proliferating inner enamel epithelium of the labial cervical loop of the incisor tooth germ. Taken together, our results suggest that dynamic expression of Six family genes represents specific stages of the developing tooth germ. This dynamic expression is embodied in changes in both space and over time, and these changes in expression suggest that Six family genes may participate in tooth germ morphogenesis and the proliferation and/or differentiation of the incisor ameloblast stem/progenitor cells.

  15. Introduction to Germ Cell Development in C. elegans

    PubMed Central

    Pazdernik, Nanette; Schedl, Tim

    2013-01-01

    A central feature of the continuum of life in sexually reproducing metazoans is the cycle of the germline from one generation to the next. This volume describes the cycle of the germline for Caenorhabditis elegans, through chapters that are focused on distinct aspects or processes in germ cell development. Topics include sequential and dependent processes such as specification of germ cells as distinct from somatic cells, sex determination, stem cell proliferative fate versus meiotic development decision, recombination/ progression through meiotic prophase, contemporaneous processes such as gametogenesis, meiotic development and apoptosis, and continuing the cycle into the next generation through fertilization and the oocyte-to-embryo-transition. Throughout germ cell development, translational control and epigenetic mechanisms play prominent roles. These different aspects of germ cell development are seamlessly integrated under optimal conditions and are modified in the different reproductive strategies that are employed by C. elegans under harsh environmental conditions. In this chapter we set the stage by providing a brief background on the C. elegans system and germ cell development, indicating processes in the cycle of the germline that are covered in each chapter. PMID:22872472

  16. Spatiotemporal expression of caveolin-1 and EMMPRIN during mouse tooth development.

    PubMed

    Shi, Lu; Li, Lingyun; Wang, Ding; Li, Shu; Chen, Zhi; An, Zhengwen

    2016-06-01

    Caveolin-1 is a scaffolding protein involved in the formation of cholesterol-rich caveolae lipid rafts within the plasma membrane and is capable of collecting signaling molecules into the caveolae and regulating their activity, including extracellular matrix metalloproteinase inducer (EMMPRIN). However, detailed expression patterns of caveolin-1 and EMMPRIN in the developing dental germ are largely unknown. The present study investigated the expression patterns of caveolin-1 and EMMPRIN in the developing mouse tooth germ by immunohistochemistry and real-time polymerase chain reaction. At the bud stage, caveolin-1 expression was initiated in the epithelium bud and mesenchymal cells, while EMMPRIN was weakly expressed at this stage. At the cap stage, caveolin-1 protein was located in the lingual part of the tooth germ; however, EMMPRIN protein was located in the labial part. From the bell stage to 2 days postnatal, caveolin-1 expression was detected in the ameloblasts and cervical loop area; with EMMPRIN expression in the ameloblasts and odontoblasts. Real-time polymerase chain reaction results showed that both caveolin-1 and EMMPRIN mRNA levels increased gradually with progression of developmental stages, and peaked at day two postnatal. The current finding suggests that both caveolin-1 and EMMPRIN take part in mouse tooth development, especially in the differentiation and organization of odontogenic tissues.

  17. Hormonal control of germ cell development and spermatogenesis.

    PubMed

    O'Shaughnessy, Peter J

    2014-05-01

    Spermatogenesis is completely dependent on the pituitary hormone follicle-stimulating hormone (FSH) and androgens locally produced in response to luteinising hormone (LH). This dual control has been known since the 1930s and 1940s but more recent work, particularly using transgenic mice, has allowed us to determine which parts of the spermatogenic pathway are regulated by each hormone. During the first spermatogenic cycle after puberty both FSH and androgen act to limit the massive wave of germ cell apoptosis which occurs at this time. The established role of FSH in all cycles is to increase spermatogonial and subsequent spermatocyte numbers with a likely effect also on spermiation. Mice lacking FSH or its receptor are fertile, albeit with reduced germ cell numbers, and so this hormone is not an essential regulator of spermatogenesis but acts to optimise germ cell production Androgens also appear to regulate spermatogonial proliferation but, crucially, they are also required to allow spermatocytes to complete meiosis and form spermatids. Animals lacking androgen receptors fail to generate post-meiotic germ cells, therefore, and are infertile. There is also strong evidence that androgens act to ensure appropriate spermiation of mature spermatids. Androgen regulation of spermatogenesis is dependent upon action on the Sertoli cell but recent studies have shown that androgenic stimulation of the peritubular myoid cells is also essential for normal germ cells development. While FSH or androgen alone will both stimulate germ cell development, together they act synergistically to maximise germ cell number. The other hormones/local factors which can regulate spermatogenesis include activins and estrogens although their role in normal physiological regulation of this process needs to be more clearly established. Regulation of spermatogenesis in primates appears to be similar to that in rodents although the role of FSH may be greater. While our knowledge of hormone function

  18. An evolutionary view on tooth development and replacement in wild Atlantic salmon (Salmo salar L.).

    PubMed

    Huysseune, A; Witten, P E

    2008-01-01

    To gain an insight into the evolution of tooth replacement mechanisms, we studied the development of first-generation and replacement teeth on the dentary of wild Atlantic salmon (Salmo salar L.), a protacanthopterygian teleost, using serially sectioned heads of early posthatching stages as well as adults. First-generation teeth develop within the oral epithelium. The anlage of the replacement tooth is first seen as a placode-like thickening of the outer dental epithelium of the predecessor, at its lingual and caudal side. Ongoing development of the replacement tooth germ is characterized by the elaboration of a population of epithelial cells, termed here the middle dental epithelium, apposed to the inner dental epithelium on the lingual side of the tooth germ. Before the formation of the new successor, a single-layered outer dental epithelium segregates from the middle dental epithelium. The dental organs of the predecessor and the successor remain broadly interconnected. The absence of a discrete successional dental lamina in salmon stands in sharp contrast to what is observed in other teleosts, even those that share with salmon the extraosseous formation of replacement teeth. The mode of tooth replacement in Atlantic salmon displays several characters similar to those observed in the shark Squalus acanthias. To interpret similarities in tooth replacement between Atlantic salmon and chondrichthyans as a case of convergence, or to see them as a result of a heterochronic shift, requires knowledge on the replacement process in more basal actinopterygian lineages. The possibility that the middle dental epithelium functionally substitutes for a successional lamina, and could be a source of stem cells, whose descendants subsequently contribute to the placode of the new replacement tooth, needs to be explored.

  19. Distribution of amelotin in mouse tooth development.

    PubMed

    Gao, Yuguang; Wang, Wanchun; Sun, Yan; Zhang, Juanjuan; Li, Dongliang; Wei, Yahong; Han, Tingting

    2010-01-01

    Amelotin is expressed and secreted by ameloblasts in tooth development, but amelotin distribution during enamel development is not clear. In this report, we first investigated amelotin expression in developing teeth by immunohistochemistry. Amelotin was detected in the enamel matrix at the secretion and maturation stages of enamel development. Amelotin was also observed at Tomes' processes on the apical ends of secretory ameloblasts. We then compared amelotin gene expression with those of amelogenin, enamelin, and ameloblastin in the mandibles of postnatal mice by RT-PCR. The expression of amelotin was detected as early as in postnatal day 0 mandibles and amelotin was coexpressed with amelogenin, ameloblastin, and enamelin during tooth development. These data strongly suggest that amelotin is an enamel matrix protein expressed at the secretion and maturation stages of enamel development. (c) 2009 Wiley-Liss, Inc.

  20. Etoposide damages female germ cells in the developing ovary.

    PubMed

    Stefansdottir, Agnes; Johnston, Zoe C; Powles-Glover, Nicola; Anderson, Richard A; Adams, Ian R; Spears, Norah

    2016-08-11

    As with many anti-cancer drugs, the topoisomerase II inhibitor etoposide is considered safe for administration to women in the second and third trimesters of pregnancy, but assessment of effects on the developing fetus have been limited. The purpose of this research was to examine the effect of etoposide on germ cells in the developing ovary. Mouse ovary tissue culture was used as the experimental model, thus allowing us to examine effects of etoposide on all stages of germ cell development in the same way, in vitro. Fetal ovaries from embryonic day 13.5 CD1 mice or neonatal ovaries from postnatal day 0 CD1 mice were cultured with 50-150 ng ml(-1) or 50-200 ng ml(-1) etoposide respectively, concentrations that are low relative to that in patient serum. When fetal ovaries were treated prior to follicle formation, etoposide resulted in dose-dependent damage, with 150 ng ml(-1) inducing a near-complete absence of healthy follicles. In contrast, treatment of neonatal ovaries, after follicle formation, had no effect on follicle numbers and only a minor effect on follicle health, even at 200 ng ml(-1). The sensitivity of female germ cells to etoposide coincided with topoisomerase IIα expression: in the developing ovary of both mouse and human, topoisomerase IIα was expressed in germ cells only prior to follicle formation. Exposure of pre-follicular ovaries, in which topoisomerase IIα expression was germ cell-specific, resulted in a near-complete elimination of germ cells prior to follicle formation, with the remaining germ cells going on to form unhealthy follicles by the end of culture. In contrast, exposure to follicle-enclosed oocytes, which no longer expressed topoisomerase IIα in the germ cells, had no effect on total follicle numbers or health, the only effect seen specific to transitional follicles. Results indicate the potential for adverse effects on fetal ovarian development if etoposide is administered to pregnant women when germ cells are not yet

  1. Developing a biomimetic tooth bud model.

    PubMed

    Smith, Elizabeth E; Zhang, Weibo; Schiele, Nathan R; Khademhosseini, Ali; Kuo, Catherine K; Yelick, Pamela C

    2017-01-08

    A long-term goal is to bioengineer, fully functional, living teeth for regenerative medicine and dentistry applications. Biologically based replacement teeth would avoid insufficiencies of the currently used dental implants. Using natural tooth development as a guide, a model was fabricated using post-natal porcine dental epithelial (pDE), porcine dental mesenchymal (pDM) progenitor cells, and human umbilical vein endothelial cells (HUVEC) encapsulated within gelatin methacrylate (GelMA) hydrogels. Previous publications have shown that post-natal DE and DM cells seeded onto synthetic scaffolds exhibited mineralized tooth crowns composed of dentin and enamel. However, these tooth structures were small and formed within the pores of the scaffolds. The present study shows that dental cell-encapsulated GelMA constructs can support mineralized dental tissue formation of predictable size and shape. Individually encapsulated pDE or pDM cell GelMA constructs were analysed to identify formulas that supported pDE and pDM cell attachment, spreading, metabolic activity, and neo-vasculature formation with co-seeded endothelial cells (HUVECs). GelMa constructs consisting of pDE-HUVECS in 3% GelMA and pDM-HUVECs within 5% GelMA supported dental cell differentiation and vascular mineralized dental tissue formation in vivo. These studies are the first to demonstrate the use of GelMA hydrogels to support the formation of post-natal dental progenitor cell-derived mineralized and functionally vascularized tissues of specified size and shape. These results introduce a novel three-dimensional biomimetic tooth bud model for eventual bioengineered tooth replacement teeth in humans. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

  2. Estimation of gestational age from tooth germs: Biometric study of DentaScan images.

    PubMed

    Lalys, Loïc; Ruquet, Michel; Tardivo, Delphine; Laibi, Salim; Bartoli, Christophe; Adalian, Pascal; Panuel, Michel; Leonetti, Georges; Foti, Bruno

    2011-01-01

    The few available studies on fetal age estimation concern very small samples, and statistical analysis is sometimes inadequate. In this survey, we used germs of deciduous teeth to estimate fetal age. Forty-nine fetuses and 40 mandibles were scanned, and observations and measurements were made on DentaScan images. After checking their repeatability and reproducibility (analysis of variance), we defined thresholds using Fisher's linear discriminant analysis to calculate the probability that a fetus was over or below a predefined age threshold. The forensic threshold which is of particular interest in France is 22 weeks amenorrhea. Relationships between fetal age and deciduous germ measurements were then sought by multiple linear regression. The thresholds gave very good results: 91.84% of good probability for the threshold of 22 weeks amenorrhea with no chance of error. The most precise age evaluation obtained nevertheless gave a range of ±4.6 weeks amenorrhea, so greater accuracy is still needed. © 2010 American Academy of Forensic Sciences.

  3. Antagonistic Functions of USAG-1 and RUNX2 during Tooth Development

    PubMed Central

    Togo, Yumiko; Takahashi, Katsu; Saito, Kazuyuki; Kiso, Honoka; Tsukamoto, Hiroko; Huang, Boyen; Yanagita, Motoko; Sugai, Manabu; Harada, Hidemitsu; Komori, Toshihisa; Shimizu, Akira; MacDougall, Mary; Bessho, Kazuhisa

    2016-01-01

    Supernumerary teeth and tooth agenesis are common morphological anomalies in humans. We previously obtained evidence that supernumerary maxillary incisors form as a result of the successive development of the rudimentary maxillary incisor tooth germ in Usag-1 null mice. The development of tooth germs is arrested in Runx2 null mice, and such mice also exhibit lingual epithelial buds associated with the upper molars and incisors. The aim of this study is to investigate the potential crosstalk between Usag-1 and Runx2 during tooth development. In the present study, three interesting phenomena were observed in double null Usag-1-/-/Runx2-/- mice: the prevalence of supernumerary teeth was lower than in Usag-1 null mice; tooth development progressed further compared than in Runx2 null mice; and the frequency of molar lingual buds was lower than in Runx2 null mice. Therefore, we suggest that RUNX2 and USAG-1 act in an antagonistic manner. The lingual bud was completely filled with odontogenic epithelial Sox2-positive cells in the Usag-1+/+/Runx2-/- mice, whereas almost no odontogenic epithelial Sox2-positive cells contributed to supernumerary tooth formation in the rudimentary maxillary incisors of the Usag-1-/-/Runx2+/+ mice. Our findings suggest that RUNX2 directly or indirectly prevents the differentiation and/or proliferation of odontogenic epithelial Sox2-positive cells. We hypothesize that RUNX2 inhibits the bone morphogenetic protein (BMP) and/or Wnt signaling pathways regulated by USAG-1, whereas RUNX2 expression is induced by BMP signaling independently of USAG-1. PMID:27518316

  4. Essential roles of G9a in cell proliferation and differentiation during tooth development.

    PubMed

    Kamiunten, Taichi; Ideno, Hisashi; Shimada, Akemi; Arai, Yoshinori; Terashima, Tatsuo; Tomooka, Yasuhiro; Nakamura, Yoshiki; Nakashima, Kazuhisa; Kimura, Hiroshi; Shinkai, Yoichi; Tachibana, Makoto; Nifuji, Akira

    2017-08-15

    Teeth develop through interactions between epithelial and mesenchymal tissues mediated by a signaling network comprised of growth factors and transcription factors. However, little is known about how epigenetic modifiers affect signaling pathways and thereby regulate tooth formation. We previously reported that the histone 3 lysine 9 (H3K9) methyltransferase (MTase) G9a is specifically enriched in the tooth mesenchyme during mouse development. In this study, we investigated the functions of G9a in tooth development using G9a conditional knockout (KO) mice. We used Sox9-Cre mice to delete G9a in the tooth mesenchyme because Sox9 is highly expressed in the mesenchyme derived from the cranial neural crest. Immunohistochemical analyses revealed that G9a expression was significantly decreased in the mesenchyme of Sox9-Cre;G9afl/fl (G9a cKO) mice compared with that in Sox9-Cre;G9a fl/+(control) mice. Protein levels of the G9a substrate H3K9me2 were also decreased in the tooth mesenchyme. G9a cKO mice showed smaller tooth germ after embryonic day (E) 16.5 and E17.5, but not at E15.5. The developing cusp tips, which were visible in control mice, were absent in G9a cKO mice at E17.5. At 3 weeks after birth, small first molars with smaller cusps and unseparated roots were formed. Organ culture of tooth germs derived from E15.5 cKO mouse embryos showed impaired tooth development, suggesting that tooth development per se is affected independently of skull development. BrdU labeling experiments revealed that the proliferation rates were decreased in the mesenchyme in G9a cKO mice at E17.5. In addition, the proliferation rates in the tooth inner enamel epithelium were also decreased. In situ hybridization revealed altered localization of genes associated with tooth development. In cKO mice, intensively localized expression of mRNAs encoding bone morphogenic protein (Bmp2 and Bmp4) was observed in the tooth mesenchyme at E17.5, similar to the expression patterns observed in

  5. Expression of Sox genes in tooth development.

    PubMed

    Kawasaki, Katsushige; Kawasaki, Maiko; Watanabe, Momoko; Idrus, Erik; Nagai, Takahiro; Oommen, Shelly; Maeda, Takeyasu; Hagiwara, Nobuko; Que, Jianwen; Sharpe, Paul T; Ohazama, Atsushi

    2015-01-01

    Members of the Sox gene family play roles in many biological processes including organogenesis. We carried out comparative in situ hybridization analysis of seventeen sox genes (Sox1-14, 17, 18, 21) during murine odontogenesis from the epithelial thickening to the cytodifferentiation stages. Localized expression of five Sox genes (Sox6, 9, 13, 14 and 21) was observed in tooth bud epithelium. Sox13 showed restricted expression in the primary enamel knots. At the early bell stage, three Sox genes (Sox8, 11, 17 and 21) were expressed in pre-ameloblasts, whereas two others (Sox5 and 18) showed expression in odontoblasts. Sox genes thus showed a dynamic spatio-temporal expression during tooth development.

  6. Expression of Sox genes in tooth development

    PubMed Central

    KAWASAKI, KATSUSHIGE; KAWASAKI, MAIKO; WATANABE, MOMOKO; IDRUS, ERIK; NAGAI, TAKAHIRO; OOMMEN, SHELLY; MAEDA, TAKEYASU; HAGIWARA, NOBUKO; QUE, JIANWEN; SHARPE, PAUL T.; OHAZAMA, ATSUSHI

    2017-01-01

    Members of the Sox gene family play roles in many biological processes including organogenesis. We carried out comparative in situ hybridization analysis of seventeen sox genes (Sox1-14, 17, 18, 21) during murine odontogenesis from the epithelial thickening to the cytodifferentiation stages. Localized expression of five Sox genes (Sox6, 9, 13, 14 and 21) was observed in tooth bud epithelium. Sox13 showed restricted expression in the primary enamel knots. At the early bell stage, three Sox genes (Sox8, 11, 17 and 21) were expressed in pre-ameloblasts, whereas two others (Sox5 and 18) showed expression in odontoblasts. Sox genes thus showed a dynamic spatio-temporal expression during tooth development. PMID:26864488

  7. Expression of HMGB1 during tooth development.

    PubMed

    Sugars, R; Karlström, E; Christersson, C; Olsson, M-L; Wendel, M; Fried, K

    2007-03-01

    High mobility group box 1 (HMGB1) is a nuclear and cytosolic protein that can act as a transcription factor, a growth factor, or a cytokine. To elucidate a possible role for HMGB1 in tooth development, we have studied the expression of HMGB1 and its receptor RAGE (receptor for advanced glycation end-products) during the late fetal and early postnatal period of rat by using light- and electron-microscopic immunohistochemistry. Low HMGB1 protein expression was observed during fetal and newborn stages of tooth development. However, from postnatal day 5 (P5) onward, a marked increase occurred in the levels of the protein in most dental cell types. Expression was particularly high in ameloblasts and odontoblasts at regions of ongoing mineralization. Although most HMGB1 immunoreactivity was confined to cell nuclei, it was also present in odontoblast cytoplasm. At P5, ameloblasts and odontoblasts also showed RAGE immunoreactivity, and reverse transcription-polymerase chain reaction demonstrated both HMGB1 and RAGE mRNA in human dental pulp cells in vitro. Immunoblots performed on extracts from bovine dentin demonstrated a principal band at approximately 27 kDa, indicating that HMGB1 participates in tooth mineralization. The expression of both ligand and receptor suggests an autocrine/paracrine HMGB1 signalling axis in odontoblasts.

  8. A functional genomic screen in planarians identifies novel regulators of germ cell development.

    PubMed

    Wang, Yuying; Stary, Joel M; Wilhelm, James E; Newmark, Phillip A

    2010-09-15

    Germ cells serve as intriguing examples of differentiated cells that retain the capacity to generate all cell types of an organism. Here we used functional genomic approaches in planarians to identify genes required for proper germ cell development. We conducted microarray analyses and in situ hybridization to discover and validate germ cell-enriched transcripts, and then used RNAi to screen for genes required for discrete stages of germ cell development. The majority of genes we identified encode conserved RNA-binding proteins, several of which have not been implicated previously in germ cell development. We also show that a germ cell-specific subunit of the conserved transcription factor CCAAT-binding protein/nuclear factor-Y is required for maintaining spermatogonial stem cells. Our results demonstrate that conserved transcriptional and post-transcriptional mechanisms regulate germ cell development in planarians. These findings suggest that studies of planarians will inform our understanding of germ cell biology in higher organisms.

  9. A functional genomic screen in planarians identifies novel regulators of germ cell development

    PubMed Central

    Wang, Yuying; Stary, Joel M.; Wilhelm, James E.; Newmark, Phillip A.

    2010-01-01

    Germ cells serve as intriguing examples of differentiated cells that retain the capacity to generate all cell types of an organism. Here we used functional genomic approaches in planarians to identify genes required for proper germ cell development. We conducted microarray analyses and in situ hybridization to discover and validate germ cell-enriched transcripts, and then used RNAi to screen for genes required for discrete stages of germ cell development. The majority of genes we identified encode conserved RNA-binding proteins, several of which have not been implicated previously in germ cell development. We also show that a germ cell-specific subunit of the conserved transcription factor CCAAT-binding protein/nuclear factor-Y is required for maintaining spermatogonial stem cells. Our results demonstrate that conserved transcriptional and post-transcriptional mechanisms regulate germ cell development in planarians. These findings suggest that studies of planarians will inform our understanding of germ cell biology in higher organisms. PMID:20844018

  10. The non-canonical BMP and Wnt/β-catenin signaling pathways orchestrate early tooth development.

    PubMed

    Yuan, Guohua; Yang, Guobin; Zheng, Yuqian; Zhu, Xiaojing; Chen, Zhi; Zhang, Zunyi; Chen, YiPing

    2015-01-01

    BMP and Wnt signaling pathways play a crucial role in organogenesis, including tooth development. Despite extensive studies, the exact functions, as well as if and how these two pathways act coordinately in regulating early tooth development, remain elusive. In this study, we dissected regulatory functions of BMP and Wnt pathways in early tooth development using a transgenic noggin (Nog) overexpression model (K14Cre;pNog). It exhibits early arrested tooth development, accompanied by reduced cell proliferation and loss of odontogenic fate marker Pitx2 expression in the dental epithelium. We demonstrated that overexpression of Nog disrupted BMP non-canonical activity, which led to a dramatic reduction of cell proliferation rate but did not affect Pitx2 expression. We further identified a novel function of Nog by inhibiting Wnt/β-catenin signaling, causing loss of Pitx2 expression. Co-immunoprecipitation and TOPflash assays revealed direct binding of Nog to Wnts to functionally prevent Wnt/β-catenin signaling. In situ PLA and immunohistochemistry on Nog mutants confirmed in vivo interaction between endogenous Nog and Wnts and modulation of Wnt signaling by Nog in tooth germs. Genetic rescue experiments presented evidence that both BMP and Wnt signaling pathways contribute to cell proliferation regulation in the dental epithelium, with Wnt signaling also controlling the odontogenic fate. Reactivation of both BMP and Wnt signaling pathways, but not of only one of them, rescued tooth developmental defects in K14Cre;pNog mice, in which Wnt signaling can be substituted by transgenic activation of Pitx2. Our results reveal the orchestration of non-canonical BMP and Wnt/β-catenin signaling pathways in the regulation of early tooth development.

  11. The non-canonical BMP and Wnt/β-catenin signaling pathways orchestrate early tooth development

    PubMed Central

    Yuan, Guohua; Yang, Guobin; Zheng, Yuqian; Zhu, Xiaojing; Chen, Zhi; Zhang, Zunyi; Chen, YiPing

    2015-01-01

    BMP and Wnt signaling pathways play a crucial role in organogenesis, including tooth development. Despite extensive studies, the exact functions, as well as if and how these two pathways act coordinately in regulating early tooth development, remain elusive. In this study, we dissected regulatory functions of BMP and Wnt pathways in early tooth development using a transgenic noggin (Nog) overexpression model (K14Cre;pNog). It exhibits early arrested tooth development, accompanied by reduced cell proliferation and loss of odontogenic fate marker Pitx2 expression in the dental epithelium. We demonstrated that overexpression of Nog disrupted BMP non-canonical activity, which led to a dramatic reduction of cell proliferation rate but did not affect Pitx2 expression. We further identified a novel function of Nog by inhibiting Wnt/β-catenin signaling, causing loss of Pitx2 expression. Co-immunoprecipitation and TOPflash assays revealed direct binding of Nog to Wnts to functionally prevent Wnt/β-catenin signaling. In situ PLA and immunohistochemistry on Nog mutants confirmed in vivo interaction between endogenous Nog and Wnts and modulation of Wnt signaling by Nog in tooth germs. Genetic rescue experiments presented evidence that both BMP and Wnt signaling pathways contribute to cell proliferation regulation in the dental epithelium, with Wnt signaling also controlling the odontogenic fate. Reactivation of both BMP and Wnt signaling pathways, but not of only one of them, rescued tooth developmental defects in K14Cre;pNog mice, in which Wnt signaling can be substituted by transgenic activation of Pitx2. Our results reveal the orchestration of non-canonical BMP and Wnt/β-catenin signaling pathways in the regulation of early tooth development. PMID:25428587

  12. Plakophilin-1, a Novel Wnt Signaling Regulator, Is Critical for Tooth Development and Ameloblast Differentiation

    PubMed Central

    Arai, Chieko; Yamada, Aya; Saito, Kan; Ishikawa, Masaki; Xue, Han; Funada, Keita; Haruyama, Naoto; Yamada, Yoshihiko; Fukumoto, Satoshi; Takahashi, Ichiro

    2016-01-01

    Tooth morphogenesis is initiated by reciprocal interactions between the ectoderm and neural crest-derived mesenchyme, and the Wnt signaling pathway is involved in this process. We found that Plakophilin (PKP)1, which is associated with diseases such as ectodermal dysplasia/skin fragility syndrome, was highly expressed in teeth and skin, and was upregulated during tooth development. We hypothesized that PKP1 regulates Wnt signaling via its armadillo repeat domain in a manner similar to β-catenin. To determine its role in tooth development, we performed Pkp1 knockdown experiments using ex vivo organ cultures and cell cultures. Loss of Pkp1 reduced the size of tooth germs and inhibited dental epithelial cell proliferation, which was stimulated by Wnt3a. Furthermore, transfected PKP1-emerald green fluorescent protein was translocated from the plasma membrane to the nucleus upon stimulation with Wnt3a and LiCl, which required the PKP1 N terminus (amino acids 161 to 270). Localization of PKP1, which is known as an adhesion-related desmosome component, shifted to the plasma membrane during ameloblast differentiation. In addition, Pkp1 knockdown disrupted the localization of Zona occludens 1 in tight junctions and inhibited ameloblast differentiation; the two proteins were shown to directly interact by immunoprecipitation. These results implicate the participation of PKP1 in early tooth morphogenesis as an effector of canonical Wnt signaling that controls ameloblast differentiation via regulation of the cell adhesion complex. PMID:27015268

  13. The differentiation potential of gingival mesenchymal stem cells induced by apical tooth germ cell-conditioned medium

    PubMed Central

    Chen, Yan; Liu, Hongwei

    2016-01-01

    Gingival-derived mesenchymal stem cells (GMSCs) have recently been harvested; however, the use of GMSCs in periodontal tissue engineering requires further study. The present study established an indirect co-culture system between rat apical tooth germ-conditioned medium (APTG-CM) and GMSCs, in order to determine the effects on periodontal tissue differentiation in vitro and in vivo. Using the limiting dilution technique, single-colony derived human GMSCs and periodontal ligament stem cells (PDLSCs) were isolated and expanded to obtain homogeneous populations. PDLSCs were used as a positive control group. Cell cycle distribution, alkaline phosphatase (ALP) activity, mineralization behavior, expression of genes associated with a cementoblast phenotype (osteocalcin, bone sialoprotein, ALP, type I collagen, cementum-derived protein 23), and in vivo differentiation capacities of GMSCs/PDLSCs co-cultured with APTG-CM were evaluated. Flow cytometry indicated that GMSCs and PDLSCs were positive for STRO-1 and CD105, whereas CD45 expression was negative. The cell types were capable of forming colonies, and of osteogenic and adipogenic differentiation in response to appropriate stimuli. The induced GMSCs and PDLSCs exhibited numerous characteristics associated with cementoblast lineages, as indicated by increased proliferation and ALP activity, and upregulated expression of cementum-associated genes in vitro. In vivo, cementum/periodontal ligament-like structures were shown to form along the dentin surface and ceramic bovine bone in GMSCs and PDLSCs induced by APTG-CM group. Conversely, vertical fibers could not insert in the control group, which was not co-cultured with APTG-CM. In conclusion, GMSCs are likely to have a role in periodontal tissue regeneration. In addition, APTG-CM was able to provide a cementogenic microenvironment and promote differentiation of GMSCs along the cementoblastic lineage. PMID:27600358

  14. Expression of clock proteins in developing tooth.

    PubMed

    Zheng, Li; Papagerakis, Silvana; Schnell, Santiago D; Hoogerwerf, Willemijntje A; Papagerakis, Petros

    2011-01-01

    Morphological and functional changes during ameloblast and odontoblast differentiation suggest that enamel and dentin formation is under circadian control. Circadian rhythms are endogenous self-sustained oscillations with periods of 24h that control diverse physiological and metabolic processes. Mammalian clock genes play a key role in synchronizing circadian functions in many organs. However, close to nothing is known on clock genes expression during tooth development. In this work, we investigated the expression of four clock genes during tooth development. Our results showed that circadian clock genes Bmal1, clock, per1, and per2 mRNAs were detected in teeth by RT-PCR. Immunohistochemistry showed that clock protein expression was first detected in teeth at the bell stage (E17), being expressed in EOE and dental papilla cells. At post-natal day four (PN4), all four clock proteins continued to be expressed in teeth but with different intensities, being strongly expressed within the nucleus of ameloblasts and odontoblasts and down-regulated in dental pulp cells. Interestingly, at PN21 incisor, expression of clock proteins was down-regulated in odontoblasts of the crown-analogue side but expression was persisting in root-analogue side odontoblasts. In contrast, both crown and root odontoblasts were strongly stained for all four clock proteins in first molars at PN21. Within the periodontal ligament (PDL) space, epithelial rests of Malassez (ERM) showed the strongest expression among other PDL cells. Our data suggests that clock genes might be involved in the regulation of ameloblast and odontoblast functions, such as enamel and dentin protein secretion and matrix mineralization. Copyright © 2010 Elsevier B.V. All rights reserved.

  15. Deletion of Osr2 Partially Rescues Tooth Development in Runx2 Mutant Mice.

    PubMed

    Kwon, H J E; Park, E K; Jia, S; Liu, H; Lan, Y; Jiang, R

    2015-08-01

    Tooth organogenesis depends on genetically programmed sequential and reciprocal inductive interactions between the dental epithelium and neural crest-derived mesenchyme. Previous studies showed that the Msx1 and Runx2 transcription factors are required for activation of odontogenic signals, including Bmp4 and Fgf3, in the early tooth mesenchyme to drive tooth morphogenesis through the bud-to-cap transition and that Runx2 acts downstream of Msx1 to activate Fgf3 expression. Recent studies identified Osr2 as a repressor of tooth development and showed that inactivation of Osr2 rescued molar tooth morphogenesis in the Msx1(-/-) mutant mice as well as in mice with neural crest-specific inactivation of Bmp4. Here we show that Runx2 expression is expanded in the tooth bud mesenchyme in Osr2(-/-) mutant mouse embryos and is partially restored in the tooth mesenchyme in Msx1(-/-)Osr2(-/-) mutants in comparison with Msx1(-/-) and wild-type embryos. Whereas mandibular molar development arrested at the bud stage and maxillary molar development arrested at the bud-to-cap transition in Runx2(-/-) mutant mice, both mandibular and maxillary molar tooth germs progressed to the early bell stage, with rescued expression of Msx1 and Bmp4 in the dental papilla as well as expression of Bmp4, p21, and Shh in the primary enamel knot in the Osr2(-/-)Runx2(-/-) compound mutants. In contrast to the Msx1(-/-)Osr2(-/-) compound mutants, which exhibit nearly normal first molar morphogenesis, the Osr2(-/-)Runx2(-/-) compound mutant embryos failed to activate the expression of Fgf3 and Fgf10 in the dental papilla and exhibited significant deficit in cell proliferation in both the dental epithelium and mesenchyme in comparison with the control embryos. These data indicate that Runx2 synergizes with Msx1 to drive tooth morphogenesis through the bud-to-cap transition and that Runx2 controls continued tooth growth and morphogenesis beyond the cap stage through activation of Fgf3 and Fgf10 expression

  16. Deletion of Osr2 Partially Rescues Tooth Development in Runx2 Mutant Mice

    PubMed Central

    Kwon, H.J.E.; Park, E.K.; Jia, S.; Liu, H.; Lan, Y.

    2015-01-01

    Tooth organogenesis depends on genetically programmed sequential and reciprocal inductive interactions between the dental epithelium and neural crest–derived mesenchyme. Previous studies showed that the Msx1 and Runx2 transcription factors are required for activation of odontogenic signals, including Bmp4 and Fgf3, in the early tooth mesenchyme to drive tooth morphogenesis through the bud-to-cap transition and that Runx2 acts downstream of Msx1 to activate Fgf3 expression. Recent studies identified Osr2 as a repressor of tooth development and showed that inactivation of Osr2 rescued molar tooth morphogenesis in the Msx1-/- mutant mice as well as in mice with neural crest–specific inactivation of Bmp4. Here we show that Runx2 expression is expanded in the tooth bud mesenchyme in Osr2-/- mutant mouse embryos and is partially restored in the tooth mesenchyme in Msx1-/-Osr2-/- mutants in comparison with Msx1-/- and wild-type embryos. Whereas mandibular molar development arrested at the bud stage and maxillary molar development arrested at the bud-to-cap transition in Runx2-/- mutant mice, both mandibular and maxillary molar tooth germs progressed to the early bell stage, with rescued expression of Msx1 and Bmp4 in the dental papilla as well as expression of Bmp4, p21, and Shh in the primary enamel knot in the Osr2-/-Runx2-/- compound mutants. In contrast to the Msx1-/-Osr2-/- compound mutants, which exhibit nearly normal first molar morphogenesis, the Osr2-/-Runx2-/- compound mutant embryos failed to activate the expression of Fgf3 and Fgf10 in the dental papilla and exhibited significant deficit in cell proliferation in both the dental epithelium and mesenchyme in comparison with the control embryos. These data indicate that Runx2 synergizes with Msx1 to drive tooth morphogenesis through the bud-to-cap transition and that Runx2 controls continued tooth growth and morphogenesis beyond the cap stage through activation of Fgf3 and Fgf10 expression in the dental

  17. Selective accumulation of germ-line associated gene products in early development of the sea star and distinct differences from germ-line development in the sea urchin

    PubMed Central

    Fresques, Tara; Zazueta-Novoa, Vanesa; Reich, Adrian; Wessel, Gary M.

    2014-01-01

    Background Echinodermata is a diverse Phylum, a sister group to chordates, and contains diverse organisms that may be useful to understand varied mechanisms of germ-line specification. Results We tested 23 genes in development of the sea star Patiria miniata that fall into five categories: 1) Conserved germ-line factors; 2) Genes involved in the inductive mechanism of germ-line specification; 3) Germ-line associated genes; 4) Molecules involved in left-right asymmetry; and 5) Genes involved in regulation and maintenance of the genome during early embryogenesis. Overall, our results support the contention that the posterior enterocoel is a source of the germ line in the sea star P. miniata. Conclusion The germ line in this organism appears to be specified late in embryogenesis, and in a pattern more consistent with inductive interactions amongst cells. This is distinct from the mechanism seen in sea urchins, a close relative of the sea star clad. We propose that P. miniata may serve as a valuable model to study inductive mechanisms of germ-cell specification and when compared to germ-line formation in the sea urchin S. purpuratus may reveal developmental transitions that occur in the evolution of inherited and inductive mechanisms of germ-line specification. PMID:24038550

  18. Ultrastructural visualisation of proteoglycans in early unmineralised dentine of rat tooth germs stained with cuprolinic blue.

    PubMed Central

    Tenorio, D; Reid, A R; Katchburian, E

    1990-01-01

    The ultrastructural distribution and localisation of proteoglycans (PGs) of early developing rat dentine were examined using cuprolinic blue in a critical electrolyte concentration procedure. Results show that the cuprolinic blue method produces images of higher morphological quality than other cationic dyes. PGs appeared as ribbon-like electron-opaque precipitates of various sizes, ranging between 1.4 and 0.2 microns in length, distributed throughout the matrix and in close association with well preserved matrix vesicles and collagen fibrils. Matrix vesicles revealed tightly packed PG filaments which appeared to be attached to their membrane. It is possible that the close association of PG filaments with matrix vesicles and collagen indicates that PGs are related to the process of mineralisation of dentine. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 7 Fig. 8 PMID:2384338

  19. Sonic hedgehog expression during early tooth development in Suncus murinus.

    PubMed

    Miyado, Mami; Ogi, Hidenao; Yamada, Gen; Kitoh, Junzo; Jogahara, Takamichi; Oda, Sen-Ichi; Sato, Iwao; Miyado, Kenji; Sunohara, Masataka

    2007-11-16

    Tooth development is a highly organized process characterized by reciprocal interactions between epithelium and mesenchyme. However, the expression patterns and functions of molecules involved in mouse tooth development are unclear from the viewpoint of explaining human dental malformations and anomalies. Here, we show the expression of sonic hedgehog (Shh), a potent initiator of morphogenesis, during the early stages of tooth development in Suncus murinus. Initially, symmetrical, elongated expression of suncus Shh (sShh) was observed in the thin layer of dental epithelial cells along the mesial-distal axis of both jaws. As the dental epithelium continued to develop, sShh was strictly restricted to the predicted leading parts of the growing, invaginating epithelium corresponding to tooth primordia and enamel knots. We propose that some aspects of Shh function in tooth development are widely conserved in mammalian phylogeny.

  20. Tooth development in a model reptile: functional and null generation teeth in the gecko Paroedura picta.

    PubMed

    Zahradnicek, Oldrich; Horacek, Ivan; Tucker, Abigail S

    2012-09-01

    This paper describes tooth development in a basal squamate, Paroedura picta. Due to its reproductive strategy, mode of development and position within the reptiles, this gecko represents an excellent model organism for the study of reptile development. Here we document the dental pattern and development of non-functional (null generation) and functional generations of teeth during embryonic development. Tooth development is followed from initiation to cytodifferentiation and ankylosis, as the tooth germs develop from bud, through cap to bell stages. The fate of the single generation of non-functional (null generation) teeth is shown to be variable, with some teeth being expelled from the oral cavity, while others are incorporated into the functional bone and teeth, or are absorbed. Fate appears to depend on the initiation site within the oral cavity, with the first null generation teeth forming before formation of the dental lamina. We show evidence for a stratum intermedium layer in the enamel epithelium of functional teeth and show that the bicuspid shape of the teeth is created by asymmetrical deposition of enamel, and not by folding of the inner dental epithelium as observed in mammals.

  1. Tooth development in a model reptile: functional and null generation teeth in the gecko Paroedura picta

    PubMed Central

    Zahradnicek, Oldrich; Horacek, Ivan; Tucker, Abigail S

    2012-01-01

    This paper describes tooth development in a basal squamate, Paroedura picta. Due to its reproductive strategy, mode of development and position within the reptiles, this gecko represents an excellent model organism for the study of reptile development. Here we document the dental pattern and development of non-functional (null generation) and functional generations of teeth during embryonic development. Tooth development is followed from initiation to cytodifferentiation and ankylosis, as the tooth germs develop from bud, through cap to bell stages. The fate of the single generation of non-functional (null generation) teeth is shown to be variable, with some teeth being expelled from the oral cavity, while others are incorporated into the functional bone and teeth, or are absorbed. Fate appears to depend on the initiation site within the oral cavity, with the first null generation teeth forming before formation of the dental lamina. We show evidence for a stratum intermedium layer in the enamel epithelium of functional teeth and show that the bicuspid shape of the teeth is created by asymmetrical deposition of enamel, and not by folding of the inner dental epithelium as observed in mammals. PMID:22780101

  2. Presence of Germ Cells in Disorders of Sex Development: Implications for Fertility Potential and Preservation

    PubMed Central

    Finlayson, Courtney; Fritsch, Michael K.; Johnson, Emilie K.; Rosoklija, Ilina; Gosiengfiao, Yasmin; Yerkes, Elizabeth; Madonna, Mary Beth; Woodruff, Teresa K.; Cheng, Earl

    2017-01-01

    Purpose We sought to determine the presence of germ cells in the gonads of patients with disorders of sex development to establish whether preservation of germ cells for future fertility potential is possible. We hypothesized that germ cells are present but vary by age and diagnosis. Materials and Methods We reviewed histology from patients with disorders of sex development who underwent gonadectomy/biopsy from 2002 to 2014 at a single institution for pathological classification of the gonad, composition of gonadal stroma and germ cell presence. Results A total of 44 patients were identified and germ cells were present in 68%. The presence and average number of germ cells per mm2 were analyzed by gonad type and diagnosis. By gonad type all ovotestes, most testes, ovaries and dysgenetic testes, and 15% of streak gonads had germ cells present. By diagnosis germ cells were present in all patients with complete androgen insensitivity syndrome, Denys-Drash syndrome, SRY mutation, mixed gonadal dysgenesis, ovotesticular conditions and StAR (steroid acute regulatory protein) deficiency, in some patients with persistent müllerian duct syndrome, XO/XY Turner syndrome and disorders of sex development not otherwise specified, and in none with complete or partial gonadal dysgenesis. Germ cells were present in the gonads of 88% of patients 0 to 3 years old, 50% of those 4 to 11 years old and 43% of those older than 12 years. Conclusions Germ cells were present in the majority of our cohort and the presence decreased with age. This novel, fertility driven evaluation of germ cell quantity in a variety of disorders of sex development suggests that fertility potential may be greater than previously thought. Further studies must be done to evaluate a larger population and examine germ cell quality to determine the viability of these germ cells. PMID:27840018

  3. Presence of Germ Cells in Disorders of Sex Development: Implications for Fertility Potential and Preservation.

    PubMed

    Finlayson, Courtney; Fritsch, Michael K; Johnson, Emilie K; Rosoklija, Ilina; Gosiengfiao, Yasmin; Yerkes, Elizabeth; Madonna, Mary Beth; Woodruff, Teresa K; Cheng, Earl

    2017-03-01

    We sought to determine the presence of germ cells in the gonads of patients with disorders of sex development to establish whether preservation of germ cells for future fertility potential is possible. We hypothesized that germ cells are present but vary by age and diagnosis. We reviewed histology from patients with disorders of sex development who underwent gonadectomy/biopsy from 2002 to 2014 at a single institution for pathological classification of the gonad, composition of gonadal stroma and germ cell presence. A total of 44 patients were identified and germ cells were present in 68%. The presence and average number of germ cells per mm(2) were analyzed by gonad type and diagnosis. By gonad type all ovotestes, most testes, ovaries and dysgenetic testes, and 15% of streak gonads had germ cells present. By diagnosis germ cells were present in all patients with complete androgen insensitivity syndrome, Denys-Drash syndrome, SRY mutation, mixed gonadal dysgenesis, ovotesticular conditions and StAR (steroid acute regulatory protein) deficiency, in some patients with persistent müllerian duct syndrome, XO/XY Turner syndrome and disorders of sex development not otherwise specified, and in none with complete or partial gonadal dysgenesis. Germ cells were present in the gonads of 88% of patients 0 to 3 years old, 50% of those 4 to 11 years old and 43% of those older than 12 years. Germ cells were present in the majority of our cohort and the presence decreased with age. This novel, fertility driven evaluation of germ cell quantity in a variety of disorders of sex development suggests that fertility potential may be greater than previously thought. Further studies must be done to evaluate a larger population and examine germ cell quality to determine the viability of these germ cells. Copyright © 2017 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

  4. Isolation and characterization of stem cells derived from human third molar tooth germs of young adults: implications in neo-vascularization, osteo-, adipo- and neurogenesis.

    PubMed

    Yalvac, M E; Ramazanoglu, M; Rizvanov, A A; Sahin, F; Bayrak, O F; Salli, U; Palotás, A; Kose, G T

    2010-04-01

    A number of studies have reported in the last decade that human tooth germs contain multipotent cells that give rise to dental and peri-odontal structures. The dental pulp, third molars in particular, have been shown to be a significant stem cell source. In this study, we isolated and characterized human tooth germ stem cells (hTGSCs) from third molars and assessed the expression of developmentally important transcription factors, such as oct4, sox2, klf4, nanog and c-myc, to determine their pluri-potency. Flow-cytometry analysis revealed that hTGSCs were positive for CD73, CD90, CD105 and CD166, but negative for CD34, CD45 and CD133, suggesting that these cells are mesenchymal-like stem cells. Under specific culture conditions, hTGSCs differentiated into osteogenic, adipogenic and neurogenic cells, as well as formed tube-like structures in Matrigel assay. hTGSCs showed significant levels of expression of sox2 and c-myc messenger RNA (mRNA), and a very high level of expression of klf4 mRNA when compared with human embryonic stem cells. This study reports for the first time that hTGSCs express developmentally important transcription factors that could render hTGSCs an attractive candidate for future somatic cell re-programming studies to differentiate germs into various tissue types, such as neurons and vascular structures. In addition, these multipotential hTGSCs could be important stem cell sources for autologous transplantation.

  5. [Clinical consequences of dioxins exposure during tooth development].

    PubMed

    Maurin, J C; Bleicher, F; Magloire, H

    2005-11-01

    Commonly designed by the term "dioxins", polychlorinated aromatic hydrocarbons are environmental pollutants leading to several toxic effects during development and growth in embryo and child. The general consequences of dioxin exposure are particularly well-documented whereas only few data are mentioned by the experts concerning tooth development. However, studies performed in rodents have shown many disruptions during odontogenesis and enamel mineralisation. Moreover, recent epidemiological studies have demonstrated in human the incidence of dioxin exposure on enamel hypomineralisation and hypodontia. The aim of this review is to report recent data about consequences of dioxin exposure on tooth development, tooth being considered as a biological marker of potential dioxin poisoning.

  6. The Molecular Circuit Regulating Tooth Development in Crocodilians.

    PubMed

    Tsai, S; Abdelhamid, A; Khan, M K; Elkarargy, A; Widelitz, R B; Chuong, C M; Wu, P

    2016-12-01

    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. © International & American Associations for Dental Research 2016.

  7. Insights into female germ cell biology: from in vivo development to in vitro derivations

    PubMed Central

    Jung, Dajung; Kee, Kehkooi

    2015-01-01

    Understanding the mechanisms of human germ cell biology is important for developing infertility treatments. However, little is known about the mechanisms that regulate human gametogenesis due to the difficulties in collecting samples, especially germ cells during fetal development. In contrast to the mitotic arrest of spermatogonia stem cells in the fetal testis, female germ cells proceed into meiosis and began folliculogenesis in fetal ovaries. Regulations of these developmental events, including the initiation of meiosis and the endowment of primordial follicles, remain an enigma. Studying the molecular mechanisms of female germ cell biology in the human ovary has been mostly limited to spatiotemporal characterizations of genes or proteins. Recent efforts in utilizing in vitro differentiation system of stem cells to derive germ cells have allowed researchers to begin studying molecular mechanisms during human germ cell development. Meanwhile, the possibility of isolating female germline stem cells in adult ovaries also excites researchers and generates many debates. This review will mainly focus on presenting and discussing recent in vivo and in vitro studies on female germ cell biology in human. The topics will highlight the progress made in understanding the three main stages of germ cell developments: namely, primordial germ cell formation, meiotic initiation, and folliculogenesis. PMID:25652637

  8. Insights into female germ cell biology: from in vivo development to in vitro derivations.

    PubMed

    Jung, Dajung; Kee, Kehkooi

    2015-01-01

    Understanding the mechanisms of human germ cell biology is important for developing infertility treatments. However, little is known about the mechanisms that regulate human gametogenesis due to the difficulties in collecting samples, especially germ cells during fetal development. In contrast to the mitotic arrest of spermatogonia stem cells in the fetal testis, female germ cells proceed into meiosis and began folliculogenesis in fetal ovaries. Regulations of these developmental events, including the initiation of meiosis and the endowment of primordial follicles, remain an enigma. Studying the molecular mechanisms of female germ cell biology in the human ovary has been mostly limited to spatiotemporal characterizations of genes or proteins. Recent efforts in utilizing in vitro differentiation system of stem cells to derive germ cells have allowed researchers to begin studying molecular mechanisms during human germ cell development. Meanwhile, the possibility of isolating female germline stem cells in adult ovaries also excites researchers and generates many debates. This review will mainly focus on presenting and discussing recent in vivo and in vitro studies on female germ cell biology in human. The topics will highlight the progress made in understanding the three main stages of germ cell developments: namely, primordial germ cell formation, meiotic initiation, and folliculogenesis.

  9. FHL2 mediates tooth development and human dental pulp cell differentiation into odontoblasts, partially by interacting with Runx2.

    PubMed

    Du, Jianxin; Wang, Qiang; Yang, Pishan; Wang, Xiaoying

    2016-04-01

    The differentiation of mesenchymal cells in tooth germ and dental pulp cells into odontoblasts is crucial for dentin formation, and the transcription factor runt-related transcription factor (Runx2) is necessary for odontoblast differentiation. Our previous study demonstrated that four and a half LIM domains 2 (FHL2) may play an important role in tooth development and human dental pulp cell differentiation. This study aimed to determine whether FHL2 mediated the mesenchymal cells in tooth development and human dental pulp cell differentiation into odontoblasts by interacting with Runx2. The expression patterns of FHL2 and Runx2 were examined at the early stages of mouse molar development using double immunofluorescence staining. Western blot analysis and co-immunoprecipitation (Co-IP) were conducted for the preliminary study of the relationship between FHL2 and Runx2 in human dental pulp cell differentiation into odontoblasts. Results of double immunofluorescence staining showed that FHL2 and Runx2 exhibited similar expression patterns at the early stages of tooth development. Western blot analysis indicated that the expression patterns of FHL2 and Runx2 were synchronized on day 7 of induction, whereas those on day 14 differed. Co-IP analysis revealed positive bands of protein complexes, revealing the interaction of FHL2 and Runx2 on days 0, 7 and 14 of induction. Our data suggested that FHL2 might interact with Runx2 to mediate mesenchymal cell differentiation at the early stages of tooth development and human dental pulp cell differentiation.

  10. Chemerin-ChemR23 Signaling in Tooth Development

    PubMed Central

    Ohira, T.; Spear, D.; Azimi, N.; Andreeva, V.; Yelick, P.C.

    2012-01-01

    Our long-term goal is to identify and characterize molecular mechanisms regulating tooth development, including those mediating the critical dental epithelial-dental mesenchymal (DE-DM) cell interactions required for normal tooth development. The goal of this study was to investigate Chemerin (Rarres2)/ChemR23(Cmklr1) signaling in DE-DM cell interactions in normal tooth development. Here we present, for the first time, tissue-specific expression patterns of Chemerin and ChemR23 in mouse tooth development. We show that Chemerin is expressed in cultured DE progenitor cells, while ChemR23 is expressed in cultured DM cells. Moreover, we demonstrate that ribosomal protein S6 (rS6) and Akt, downstream targets of Chemerin/ChemR23 signaling, are phosphorylated in response to Chemerin/ChemR23 signaling in vitro and are expressed in mouse tooth development. Together, these results suggest roles for Chemerin/ChemR23-mediated DE-DM cell signaling during tooth morphogenesis. PMID:23053848

  11. nanos function is essential for development and regeneration of planarian germ cells.

    PubMed

    Wang, Yuying; Zayas, Ricardo M; Guo, Tingxia; Newmark, Phillip A

    2007-04-03

    Germ cells are required for the successful propagation of sexually reproducing species. Understanding the mechanisms by which these cells are specified and how their totipotency is established and maintained has important biomedical and evolutionary implications. Freshwater planarians serve as fascinating models for studying these questions. They can regenerate germ cells from fragments of adult tissues that lack reproductive structures, suggesting that inductive signaling is involved in planarian germ cell specification. To study the development and regeneration of planarian germ cells, we have functionally characterized an ortholog of nanos, a gene required for germ cell development in diverse organisms, from Schmidtea mediterranea. In the hermaphroditic strain of this species, Smed-nanos mRNA is detected in developing, regenerating, and mature ovaries and testes. However, it is not detected in the vast majority of newly hatched planarians or in small tissue fragments that will ultimately regenerate germ cells, consistent with an epigenetic origin of germ cells. We show that Smed-nanos RNA interference (RNAi) results in failure to develop, regenerate, or maintain gonads in sexual planarians. Unexpectedly, Smed-nanos mRNA is also detected in presumptive testes primordia of asexual individuals that reproduce strictly by fission. These presumptive germ cells are lost after Smed-nanos RNAi, suggesting that asexual planarians specify germ cells, but their differentiation is blocked downstream of Smed-nanos function. Our results reveal a conserved function of nanos in germ cell development in planarians and suggest that these animals will serve as useful models for dissecting the molecular basis of epigenetic germ cell specification.

  12. Expression of fibroblast growth factors (Fgfs) in murine tooth development.

    PubMed

    Porntaveetus, Thantrira; Otsuka-Tanaka, Yoko; Basson, M Albert; Moon, Anne M; Sharpe, Paul T; Ohazama, Atsushi

    2011-05-01

    Fgf signalling is known to play critical roles in tooth development. Twenty-two Fgf ligands have been identified in mammals, but expression of only 10 in molars and three in the incisor loop stem cell region have been documented in murine tooth development. Our understanding of Fgf signalling in tooth development thus remains incomplete and we therefore carried out comparative in situ hybridisation analysis of unexamined Fgf ligands (eight in molars and 15 in cervical loops of incisors; Fgf11-Fgf14 were excluded from this analysis because they are not secreted and do not activate Fgf receptors) during tooth development. To identify where Fgf signalling is activated, we also examined the expression of Etv4 and Etv5, considered to be transcriptional targets of the Fgf signalling pathway. In molar tooth development, the expression of Fgf15 and Fgf20 was restricted to the primary enamel knots, whereas Etv4 and Etv5 were expressed in cells surrounding the primary enamel knots. Fgf20 expression was observed in the secondary enamel knots, whereas Fgf15 showed localised expression in the adjacent mesenchyme. Fgf16, Etv4 and Etv5 were strongly expressed in the ameloblasts of molars. In the incisor cervical loop stem cell region, Fgf17, Fgf18, Etv4 and Etv5 showed a restricted expression pattern. These molecules thus show dynamic temporo-spatial expression in murine tooth development. We also analysed teeth in Fgf15(-/-) and Fgf15(-/-) ;Fgf8(+/-) mutant mice. Neither mutant showed significant abnormalities in tooth development, indicating likely functional redundancy. © 2011 The Authors. Journal of Anatomy © 2011 Anatomical Society of Great Britain and Ireland.

  13. Expression of fibroblast growth factors (Fgfs) in murine tooth development

    PubMed Central

    Porntaveetus, Thantrira; Otsuka-Tanaka, Yoko; Albert Basson, M; Moon, Anne M; Sharpe, Paul T; Ohazama, Atsushi

    2011-01-01

    Fgf signalling is known to play critical roles in tooth development. Twenty-two Fgf ligands have been identified in mammals, but expression of only 10 in molars and three in the incisor loop stem cell region have been documented in murine tooth development. Our understanding of Fgf signalling in tooth development thus remains incomplete and we therefore carried out comparative in situ hybridisation analysis of unexamined Fgf ligands (eight in molars and 15 in cervical loops of incisors; Fgf11–Fgf14 were excluded from this analysis because they are not secreted and do not activate Fgf receptors) during tooth development. To identify where Fgf signalling is activated, we also examined the expression of Etv4 and Etv5, considered to be transcriptional targets of the Fgf signalling pathway. In molar tooth development, the expression of Fgf15 and Fgf20 was restricted to the primary enamel knots, whereas Etv4 and Etv5 were expressed in cells surrounding the primary enamel knots. Fgf20 expression was observed in the secondary enamel knots, whereas Fgf15 showed localised expression in the adjacent mesenchyme. Fgf16, Etv4 and Etv5 were strongly expressed in the ameloblasts of molars. In the incisor cervical loop stem cell region, Fgf17, Fgf18, Etv4 and Etv5 showed a restricted expression pattern. These molecules thus show dynamic temporo-spatial expression in murine tooth development. We also analysed teeth in Fgf15−/− and Fgf15−/−;Fgf8+/− mutant mice. Neither mutant showed significant abnormalities in tooth development, indicating likely functional redundancy. PMID:21332717

  14. Germ cells influence cord formation and Leydig cell gene expression during mouse testis development.

    PubMed

    Rios-Rojas, Clarissa; Spiller, Cassy; Bowles, Josephine; Koopman, Peter

    2016-04-01

    It is widely accepted that, during the development of testes in the mammalian embryo, male germ cells are influenced by signals from the surrounding somatic cells, but not vice versa, so that germ cells are dispensable for the formation of testes. We now demonstrate that development of the mouse fetal testis is compromised in the absence of germ cells. Using two- and three-dimensional imaging techniques, we reveal that W(e)/W(e) mutant testes devoid of germ cells have misshapen and poorly organized cords. We also found that mutant gonads have fewer Sertoli cells than normal and that the Leydig cells express key markers at higher than normal levels. These observations point to the existence of germ cell-derived signals that directly or indirectly affect the Sertoli and Leydig cell populations, and provide a new paradigm for the organogenesis of the mammalian testes. © 2015 Wiley Periodicals, Inc.

  15. Specific variants of general transcription factors regulate germ cell development in diverse organisms

    PubMed Central

    Freiman, Richard N.

    2009-01-01

    Through the reductive divisions of meiosis, sexually reproducing organisms have gained the ability to produce specialized haploid cells called germ cells that fuse to establish the diploid genome of the resulting progeny. The totipotent nature of these germ cells is highlighted by their ability to provide a single fertilized egg cell with all the genetic information necessary to develop the complete repertoire of cell types of the future organism. Thus, the production of these germ cells must be tightly regulated to ensure the continued success of the germ line in future generations. One surprising germ cell development mechanism utilizes variation of the global transcriptional machinery, such as TFIID and TFIIA. Like histone variation, general transcription factor variation serves to produce gonadal-restricted or -enriched expression of selective transcriptional regulatory factors required for establishing and/or maintaining the germ line of diverse organisms. This strategy is observed among invertebrates and vertebrates, and perhaps plants, suggesting that a common theme in germ cell evolution is the diversification of selective promoter initiation factors to regulate critical gonadal-specific programs of gene expression required for sexual reproduction. This review discusses the identification and characterization of a subset of these specialized general transcription factors in diverse organisms that share a common goal of germ line regulation through transcriptional control at its most fundamental level. PMID:19437618

  16. Fibroblast growth factor signaling in mammalian tooth development.

    PubMed

    Li, Chun-Ying; Prochazka, Jan; Goodwin, Alice F; Klein, Ophir D

    2014-01-01

    In this review, we discuss the central role of fibroblast growth factor (FGF) signaling in mammalian tooth development. The FGF family consists of 22 members, most of which bind to four different receptor tyrosine kinases, which in turn signal through a cascade of intracellular proteins. This signaling regulates a number of cellular processes, including proliferation, differentiation, cell adhesion and cell mobility. FGF signaling first becomes important in the presumptive dental epithelium at the initiation stage of tooth development, and subsequently, it controls the invagination of the dental epithelium into the underlying mesenchyme. Later, FGFs are critical in tooth shape formation and differentiation of ameloblasts and odontoblasts, as well as in the development and homeostasis of the stem cell niche that fuels the continuously growing mouse incisor. In addition, FGF signaling is critical in human teeth, as mutations in genes encoding FGF ligands or receptors result in several congenital syndromes characterized by alterations in tooth number, morphology or enamel structure. The parallel roles of FGF signaling in mouse and human tooth development demonstrate the conserved importance of FGF signaling in mammalian odontogenesis.

  17. Tooth tissue engineering: optimal dental stem cell harvest based on tooth development.

    PubMed

    Duailibi, Monica Talarico; Duailibi, Silvio Eduardo; Duailibi Neto, Eduardo Felippe; Negreiros, Renata Matalon; Jorge, Waldyr Antonio; Ferreira, Lydia Masako; Vacanti, Joseph Phillip; Yelick, Pamela Crotty

    2011-07-01

    Our long-term objective is to devise reliable methods to generate biological replacement teeth exhibiting the physical properties and functions of naturally formed human teeth. Previously, we demonstrated the successful use of tissue engineering approaches to generate small, bioengineered tooth crowns from harvested pig and rat postnatal dental stem cells (DSCs). To facilitate characterizations of human DSCs, we have developed a novel radiographic staging system to accurately correlate human third molar tooth developmental stage with anticipated harvested DSC yield. Our results demonstrated that DSC yields were higher in less developed teeth (Stages 1 and 2), and lower in more developed teeth (Stages 3, 4, and 5). The greatest cell yields and colony-forming units (CFUs) capability was obtained from Stages 1 and 2 tooth dental pulp. We conclude that radiographic developmental staging can be used to accurately assess the utility of harvested human teeth for future dental tissue engineering applications. © 2011, Copyright the Authors. Artificial Organs © 2011, International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

  18. The development of complex tooth shape in reptiles

    PubMed Central

    Zahradnicek, Oldrich; Buchtova, Marcela; Dosedelova, Hana; Tucker, Abigail S.

    2014-01-01

    Reptiles have a diverse array of tooth shapes, from simple unicuspid to complex multicuspid teeth, reflecting functional adaptation to a variety of diets and eating styles. In addition to cusps, often complex longitudinal labial and lingual enamel crests are widespread and contribute to the final shape of reptile teeth. The simplest shaped unicuspid teeth have been found in piscivorous or carnivorous ancestors of recent diapsid reptiles and they are also present in some extant carnivores such as crocodiles and snakes. However, the ancestral tooth shape for squamate reptiles is thought to be bicuspid, indicating an insectivorous diet. The development of bicuspid teeth in lizards has recently been published, indicating that the mechanisms used to create cusps and crests are very distinct from those that shape cusps in mammals. Here, we introduce the large variety of tooth shapes found in lizards and compare the morphology and development of bicuspid, tricuspid, and pentacuspid teeth, with the aim of understanding how such tooth shapes are generated. Next, we discuss whether the processes used to form such morphologies are conserved between divergent lizards and whether the underlying mechanisms share similarities with those of mammals. In particular, we will focus on the complex teeth of the chameleon, gecko, varanus, and anole lizards using SEM and histology to compare the tooth crown morphology and embryonic development. PMID:24611053

  19. The development of complex tooth shape in reptiles.

    PubMed

    Zahradnicek, Oldrich; Buchtova, Marcela; Dosedelova, Hana; Tucker, Abigail S

    2014-01-01

    Reptiles have a diverse array of tooth shapes, from simple unicuspid to complex multicuspid teeth, reflecting functional adaptation to a variety of diets and eating styles. In addition to cusps, often complex longitudinal labial and lingual enamel crests are widespread and contribute to the final shape of reptile teeth. The simplest shaped unicuspid teeth have been found in piscivorous or carnivorous ancestors of recent diapsid reptiles and they are also present in some extant carnivores such as crocodiles and snakes. However, the ancestral tooth shape for squamate reptiles is thought to be bicuspid, indicating an insectivorous diet. The development of bicuspid teeth in lizards has recently been published, indicating that the mechanisms used to create cusps and crests are very distinct from those that shape cusps in mammals. Here, we introduce the large variety of tooth shapes found in lizards and compare the morphology and development of bicuspid, tricuspid, and pentacuspid teeth, with the aim of understanding how such tooth shapes are generated. Next, we discuss whether the processes used to form such morphologies are conserved between divergent lizards and whether the underlying mechanisms share similarities with those of mammals. In particular, we will focus on the complex teeth of the chameleon, gecko, varanus, and anole lizards using SEM and histology to compare the tooth crown morphology and embryonic development.

  20. Control over the morphology and segregation of Zebrafish germ cell granules during embryonic development

    PubMed Central

    Strasser, Markus J; Mackenzie, Natalia C; Dumstrei, Karin; Nakkrasae, La-Iad; Stebler, Jürg; Raz, Erez

    2008-01-01

    Background Zebrafish germ cells contain granular-like structures, organized around the cell nucleus. These structures share common features with polar granules in Drosophila, germinal granules in Xenopus and chromatoid bodies in mice germ cells, such as the localization of the zebrafish Vasa, Piwi and Nanos proteins, among others. Little is known about the structure of these granules as well as their segregation in mitosis during early germ-cell development. Results Using transgenic fish expressing a fluorescently labeled novel component of Zebrafish germ cell granules termed Granulito, we followed the morphology and distribution of the granules. We show that whereas these granules initially exhibit a wide size variation, by the end of the first day of development they become a homogeneous population of medium size granules. We investigated this resizing event and demonstrated the role of microtubules and the minus-end microtubule dependent motor protein Dynein in the process. Last, we show that the function of the germ cell granule resident protein the Tudor domain containing protein-7 (Tdrd7) is required for determination of granule morphology and number. Conclusion Our results suggest that Zebrafish germ cell granules undergo a transformation process, which involves germ cell specific proteins as well as the microtubular network. PMID:18507824

  1. Development of the vestigial tooth primordia as part of mouse odontogenesis.

    PubMed

    Peterková, R; Peterka, M; Viriot, L; Lesot, H

    2002-01-01

    The mouse functional dentition comprises one incisor separated from three molars by a toothless diastema in each dental quadrant. Between the incisor and molars, the embryonic tooth pattern also includes vestigial dental primordia, which undergo regression involving apoptosis in their epithelium. Apoptosis appears to play an important role in achieving the specific tooth pattern in the mouse. We documented similarities in the folding mechanism allowing the formation of the dental lamina in mice as well as in reptiles. While further budding on this dental lamina gives rise to many individual simple tooth primordia in crocodiles and lizards, budding morphogenesis of several simple tooth primordia appears to be integrated in the mouse, giving rise to enamel organs of a complex nature. The differentiation of a mammalian tooth germ during both ontogeny and phylogeny might thus include the concrescence (connation) of more primordia, putatively corresponding to simple teeth in mammalian ancestors.

  2. The biology of germ cell tumors in disorders of sex development.

    PubMed

    Hersmus, Remko; van Bever, Yolande; Wolffenbuttel, Katja P; Biermann, Katharina; Cools, Martine; Looijenga, Leendert H J

    2017-02-01

    Development of a malignant germ cell tumor, i.e., germ cell cancer (GCC) in individuals with disorders of sex development (DSD) depends on a number of (epi-)genetic factors related to early gonadal- and germ cell development, possibly related to genetic susceptibility. Fetal development of germ cells is orchestrated by strict processes involving specification, migration and the development of a proper gonadal niche. In this review we will discuss the early (epi-)genetic events in normal and aberrant germ cell and gonadal development. Focus will be on the formation of the precursor lesions of GCC in individuals who have DSD. In our view, expression of the different embryonic markers in, and epigenetic profile of the precursor lesions reflects the developmental stage in which these cells are blocked in their maturation. Therefore, these are not a primary pathogenetic driving force. Progression later in life towards a full blown cancer likely depends on additional factors such as a changed endocrine environment in a susceptible individual. Genetic susceptibility is, as evidenced by the presence of specific risk genetic variants (SNPs) in patients with a testicular GCC, related to genes involved in early germ cell and gonadal development.

  3. Management of Developing Anterior Malocclusion due to SupernumeraryTooth with Preventive and Intercep-tive Approach: A 1½ Year Case Study

    PubMed Central

    Kambalimath, HV; Banda, Naveen Reddy

    2010-01-01

    ABSTRACT Variety of clinical complications occurs due to the presence of supernumerary teeth, especially mesiodens. It may result in impaction of one or both central incisors which in turn may lead to a variety of malocclusions. Timely intervention not only prevents malocclusion but also the time taken for corrective orthodontics. A complete case report of developing mesiodens’ tooth germ resulting in malocclusion including treatment in 1½ year period is presented. PMID:27507922

  4. [Reconsidering the roles of female germ cells in ovarian development and folliculogenesis].

    PubMed

    Guigon, Céline J; Cohen-Tannoudji, Michel

    2011-01-01

    The production of fertilizable ova is the consequence of multiple events that start as soon as ovarian development and culminate at the time of ovulation. Throughout their development, germ cells are associated with companion somatic cells, which ensure germ cell survival, growth and maturation. Data obtained in vitro and in vivo on several animal models of germ cell depletion have led to uncover the many roles of germ cells on both ovarian development and folliculogenesis. During ovarian development, germ cells become progressively enclosed within epithelial structures called "ovigerous cords" constituted by pregranulosa cells, lined by a basement membrane. At the end of ovarian development, ovigerous cords fragment into primordial follicles, which are epithelial units constituted by an oocyte surrounded by a single layer of granulosa cells. Germ cells are necessary for the fragmentation of ovigerous cords into follicles, since in their absence, no follicle will form. Germ cells also ensure the differentiation of the ovarian somatic lineage, and they may inhibit the testis-differentiating pathway by preventing the conversion of pregranulosa cells into Sertoli cells, their counterpart in the testis. Regularly, primordial follicles are recruited into the growing follicle pool and initiate their growth. They develop through primary, preantral, antral and preovulatory stages before being ovulated. Interestingly, the action of the oocyte on companion somatic cells tightly depends on the follicular stage. In primordial follicles, the oocyte prevents the transdifferentiation of granulosa cells into cells resembling Sertoli cells. By contrast, as soon as the follicle enters growth, the oocyte regulates the functional differentiation of granulosa cells and at the latest stages, it prevents their premature maturation into luteal cells. Overall, these data demonstrate that the female germ cell act on companion somatic cells to regulate ovarian development and

  5. Administration of the bisphosphonate zoledronic acid during tooth development inhibits tooth eruption and formation and induces dental abnormalities in rats.

    PubMed

    Hiraga, Toru; Ninomiya, Tadashi; Hosoya, Akihiro; Nakamura, Hiroaki

    2010-06-01

    Bisphosphonates (BPs) are potent inhibitors of osteoclastic bone resorption and widely used for the treatment of osteoporosis and metastatic bone diseases. Recently, BPs have also been shown to benefit children with primary and secondary osteoporosis, including osteogenesis imperfecta; however, their long-term safety has not been established yet. Clinical and experimental studies have demonstrated that BPs delay or inhibit tooth eruption. The failure of tooth eruption causes several dental abnormalities. In this study, to determine the effects of BPs on tooth formation, the BP zoledronic acid (ZOL) was injected into 7- and 14-day-old rats, and the development of the mandibular teeth was examined. X-ray analysis demonstrated that ZOL inhibited the eruption of both incisors and molars and their formation, especially in the molar roots. Histological examination showed that, in ZOL-treated animals, alveolar bone remained unresorbed around tooth crowns, which injured ameloblasts and enamel matrix, leading to defects of the enamel. Furthermore, haphazard proliferation of odontogenic epithelium and mesenchyme associated with primitive tooth structures, which resembles human odontomas, was induced at the basal end of incisors but not around the molars. Tooth ankylosis to alveolar bone was occasionally observed in molars. These results suggest that administration of BPs during tooth development has the potential to inhibit tooth eruption and formation and to induce several types of dental abnormalities, which may be attributed to the altered osteoclastic activities.

  6. DAZ Family Proteins, Key Players for Germ Cell Development.

    PubMed

    Fu, Xia-Fei; Cheng, Shun-Feng; Wang, Lin-Qing; Yin, Shen; De Felici, Massimo; Shen, Wei

    2015-01-01

    DAZ family proteins are found almost exclusively in germ cells in distant animal species. Deletion or mutations of their encoding genes usually severely impair either oogenesis or spermatogenesis or both. The family includes Boule (or Boll), Dazl (or Dazla) and DAZ genes. Boule and Dazl are situated on autosomes while DAZ, exclusive of higher primates, is located on the Y chromosome. Deletion of DAZ gene is the most common causes of infertility in humans. These genes, encoding for RNA binding proteins, contain a highly conserved RNA recognition motif and at least one DAZ repeat encoding for a 24 amino acids sequence able to bind other mRNA binding proteins. Basically, Daz family proteins function as adaptors for target mRNA transport and activators of their translation. In some invertebrate species, BOULE protein play a pivotal role in germline specification and a conserved regulatory role in meiosis. Depending on the species, DAZL is expressed in primordial germ cells (PGCs) and/or pre-meiotic and meiotic germ cells of both sexes. Daz is found in fetal gonocytes, spermatogonia and spermatocytes of adult testes. Here we discuss DAZ family genes in a phylogenic perspective, focusing on the common and distinct features of these genes, and their pivotal roles during gametogenesis evolved during evolution.

  7. Germ cells of the centipede Strigamia maritima are specified early in embryonic development.

    PubMed

    Green, Jack E; Akam, Michael

    2014-08-15

    We provide the first systematic description of germ cell development with molecular markers in a myriapod, the centipede Strigamia maritima. By examining the expression of Strigamia vasa and nanos orthologues, we find that the primordial germ cells are specified from at least the blastoderm stage. This is a much earlier embryonic stage than previously described for centipedes, or any other member of the Myriapoda. Using these genes as markers, and taking advantage of the developmental synchrony of Strigamia embryos within single clutches, we are able to track the development of the germ cells throughout embryogenesis. We find that the germ cells accumulate at the blastopore; that the cells do not internalize through the hindgut, but rather through the closing blastopore; and that the cells undergo a long-range migration to the embryonic gonad. This is the first evidence for primordial germ cells displaying these behaviours in any myriapod. The myriapods are a phylogenetically important group in the arthropod radiation for which relatively little developmental data is currently available. Our study provides valuable comparative data that complements the growing number of studies in insects, crustaceans and chelicerates, and is important for the correct reconstruction of ancestral states and a fuller understanding of how germ cell development has evolved in different arthropod lineages.

  8. Characterization of the secretome of human tooth germ stem cells (hTGSCs) reveals neuro-protection by fine-tuning micro-environment.

    PubMed

    Yalvaç, Mehmet Emir; Yarat, Aysen; Mercan, Dilek; Rizvanov, Albert A; Palotás, András; Şahin, Fikrettin

    2013-08-01

    Bone-marrow-derived mesenchymal stem cells (MSCs) demonstrate neuro-protective effects in several disease models. By producing growth-factors, cytokines and chemokines, they promote survival of neurons in damaged brain areas. Alternative MSC sources, such as human tooth germ stem cells (hTGSCs), have been investigated for their neuro-protective properties. They ameliorate effects of neuro-toxic agents by paracrine mechanisms, however these secreted bio-active molecules are not yet characterized. Therefore, the current study aimed to provide a detailed analysis of the secretome of hTGSCs. Brain cells were exposed to various toxic materials, including Alzheimer's β-amyloid peptide (β-AP) and 6-hydroxy-dopamine (6-OHDA). When co-cultured with hTGSCs, the activity of a number of anti-oxidant enzymes (catalase, glutathione-s-transferase, glutathione-peroxidase, superoxide-dismutase) was increased and neuronal death/apoptosis was subsequently reduced. The composition of the secreted bio-active materials is influenced by various pre-existing factors such as oxygen and glucose deprivation and the age of cells (passage number). This report reveals for the first time that the neuro-protective secretome of hTGSCs and the micro-environment of cells have a mutual and dynamic impact on one another.

  9. Whole Tooth Regeneration as a Future Dental Treatment.

    PubMed

    Oshima, Masamitsu; Tsuji, Takashi

    2015-01-01

    Dental problems caused by dental caries, periodontal disease and tooth injury compromise the oral and general health issues. Current advances for the development of regenerative therapy have been influenced by our understanding of embryonic development, stem cell biology, and tissue engineering technology. Tooth regenerative therapy for tooth tissue repair and whole tooth replacement is currently expected a novel therapeutic concept with the full recovery of tooth physiological functions. Dental stem cells and cell-activating cytokines are thought to be candidate approach for tooth tissue regeneration because they have the potential to differentiate into tooth tissues in vitro and in vivo. Whole tooth replacement therapy is considered to be an attractive concept for next generation regenerative therapy as a form of bioengineered organ replacement. For realization of whole tooth regeneration, we have developed a novel three-dimensional cell manipulation method designated the "organ germ method". This method involves compartmentalisation of epithelial and mesenchymal cells at a high cell density to mimic multicellular assembly conditions and epithelial-mesenchymal interactions in organogenesis. The bioengineered tooth germ generates a structurally correct tooth in vitro, and erupted successfully with correct tooth structure when transplanted into the oral cavity. We have ectopically generated a bioengineered tooth unit composed of a mature tooth, periodontal ligament and alveolar bone, and that tooth unit was engrafted into an adult jawbone through bone integration. Bioengineered teeth were also able to perform physiological tooth functions such as mastication, periodontal ligament function and response to noxious stimuli. In this review, we describe recent findings and technologies underpinning whole tooth regenerative therapy.

  10. An Nfic-hedgehog signaling cascade regulates tooth root development

    PubMed Central

    Liu, Yang; Feng, Jifan; Li, Jingyuan; Zhao, Hu; Ho, Thach-Vu; Chai, Yang

    2015-01-01

    Coordination between the Hertwig's epithelial root sheath (HERS) and apical papilla (AP) is crucial for proper tooth root development. The hedgehog (Hh) signaling pathway and Nfic are both involved in tooth root development; however, their relationship has yet to be elucidated. Here, we establish a timecourse of mouse molar root development by histological staining of sections, and we demonstrate that Hh signaling is active before and during root development in the AP and HERS using Gli1 reporter mice. The proper pattern of Hh signaling activity in the AP is crucial for the proliferation of dental mesenchymal cells, because either inhibition with Hh inhibitors or constitutive activation of Hh signaling activity in transgenic mice leads to decreased proliferation in the AP and shorter roots. Moreover, Hh activity is elevated in Nfic−/− mice, a root defect model, whereas RNA sequencing and in situ hybridization show that the Hh attenuator Hhip is downregulated. ChIP and RNAscope analyses suggest that Nfic binds to the promoter region of Hhip. Treatment of Nfic−/− mice with Hh inhibitor partially restores cell proliferation, AP growth and root development. Taken together, our results demonstrate that an Nfic-Hhip-Hh signaling pathway is crucial for apical papilla growth and proper root formation. This discovery provides insight into the molecular mechanisms regulating tooth root development. PMID:26293299

  11. Spatial signalling mediated by the transforming growth factor-β signalling pathway during tooth formation

    PubMed Central

    He, Xin-Yu; Sun, Ke; Xu, Ruo-Shi; Tan, Jia-Li; Pi, Cai-Xia; Wan, Mian; Peng, Yi-Ran; Ye, Ling; Zheng, Li-Wei; Zhou, Xue-Dong

    2016-01-01

    Tooth development relies on sequential and reciprocal interactions between the epithelial and mesenchymal tissues, and it is continuously regulated by a variety of conserved and specific temporal-spatial signalling pathways. It is well known that suspensions of tooth germ cells can form tooth-like structures after losing the positional information provided by the epithelial and mesenchymal tissues. However, the particular stage in which the tooth germ cells start to form tooth-like structures after losing their positional information remains unclear. In this study, we investigated the reassociation of tooth germ cells suspension from different morphological stages during tooth development and the phosphorylation of Smad2/3 in this process. Four tooth morphological stages were designed in this study. The results showed that tooth germ cells formed odontogenic tissue at embryonic day (E) 14.5, which is referred to as the cap stage, and they formed tooth-like structures at E16.5, which is referred to as the early bell stage, and E18.5, which is referred to as the late bell stage. Moreover, the transforming growth factor-β signalling pathway might play a role in this process. PMID:27982023

  12. Spatial signalling mediated by the transforming growth factor-β signalling pathway during tooth formation.

    PubMed

    He, Xin-Yu; Sun, Ke; Xu, Ruo-Shi; Tan, Jia-Li; Pi, Cai-Xia; Wan, Mian; Peng, Yi-Ran; Ye, Ling; Zheng, Li-Wei; Zhou, Xue-Dong

    2016-12-16

    Tooth development relies on sequential and reciprocal interactions between the epithelial and mesenchymal tissues, and it is continuously regulated by a variety of conserved and specific temporal-spatial signalling pathways. It is well known that suspensions of tooth germ cells can form tooth-like structures after losing the positional information provided by the epithelial and mesenchymal tissues. However, the particular stage in which the tooth germ cells start to form tooth-like structures after losing their positional information remains unclear. In this study, we investigated the reassociation of tooth germ cells suspension from different morphological stages during tooth development and the phosphorylation of Smad2/3 in this process. Four tooth morphological stages were designed in this study. The results showed that tooth germ cells formed odontogenic tissue at embryonic day (E) 14.5, which is referred to as the cap stage, and they formed tooth-like structures at E16.5, which is referred to as the early bell stage, and E18.5, which is referred to as the late bell stage. Moreover, the transforming growth factor-β signalling pathway might play a role in this process.

  13. Pathogenesis of germ cell neoplasia in testicular dysgenesis and disorders of sex development.

    PubMed

    Jørgensen, Anne; Lindhardt Johansen, Marie; Juul, Anders; Skakkebaek, Niels E; Main, Katharina M; Rajpert-De Meyts, Ewa

    2015-09-01

    Development of human gonads is a sex-dimorphic process which evolved to produce sex-specific types of germ cells. The process of gonadal sex differentiation is directed by the action of the somatic cells and ultimately results in germ cells differentiating to become functional gametes through spermatogenesis or oogenesis. This tightly controlled process depends on the proper sequential expression of many genes and signalling pathways. Disturbances of this process can be manifested as a large spectrum of disorders, ranging from severe disorders of sex development (DSD) to - in the genetic male - mild reproductive problems within the testicular dysgenesis syndrome (TDS), with large overlap between the syndromes. These disorders carry an increased but variable risk of germ cell neoplasia. In this review, we discuss the pathogenesis of germ cell neoplasia associated with gonadal dysgenesis, especially in individuals with 46,XY DSD. We summarise knowledge concerning development and sex differentiation of human gonads, with focus on sex-dimorphic steps of germ cell maturation, including meiosis. We also briefly outline the histopathology of germ cell neoplasia in situ (GCNIS) and gonadoblastoma (GDB), which are essentially the same precursor lesion but with different morphological structure dependent upon the masculinisation of the somatic niche. To assess the risk of germ cell neoplasia in different types of DSD, we have performed a PubMed search and provide here a synthesis of the evidence from studies published since 2006. We present a model for pathogenesis of GCNIS/GDB in TDS/DSD, with the risk of malignancy determined by the presence of the testis-inducing Y chromosome and the degree of masculinisation. The associations between phenotype and the risk of neoplasia are likely further modulated in each individual by the constellation of the gene polymorphisms and environmental factors. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. Proliferating cell nuclear antigen (PCNA) expression in tooth primordia in the field vole (Microtus agrestis, Rodentia).

    PubMed

    Matulová, P; Witter, K; Mísek, I

    2002-01-01

    Cell proliferation in developing tooth germs has been studied particularly using bromodeoxyuridine (BrdU) incorporation into growing tooth primordia and by counting and three-dimensional (3D) reconstruction of mitoses in serial sections of developing teeth. PCNA has been proposed as an alternative marker of proliferation activity. The aim of our study was to detect immunohistochemically locations of PCNA-positive cells in developing tooth germs of Microtus agrestis (Rodentia). PCNA expression could be distinguished in oral epithelium and mesenchyme before first signs of dental lamina elevation. During bud, cap, and bell stages, positive immunostaining could be observed at defined sites in enamel organ, tooth papilla, and dental follicle. Rudimental tooth germs of the upper diastema, enamel knots, and inner enamel epithelium at day of ontogeny 18 and 19 showed negative reaction. PCNA marks cycling and early G0 cells and can be used successfully as a proliferation marker even in collection material.

  15. Expression of Clu and Tgfb1 during murine tooth development: effects of in-vivo transfection with anti-miR-214.

    PubMed

    Khan, Qalb-E-Saleem; Sehic, Amer; Khuu, Cuong; Risnes, Steinar; Osmundsen, Harald

    2013-08-01

    Expression of clusterin (Clu) in the murine first molar tooth germ was markedly increased at postnatal developmental stages. The time-course of expression of this gene paralleled those of other genes encoding proteins involved during the secretory phase of odontogenesis, as described previously. Immunohistochemical studies of clusterin in murine molar tooth germs suggested this protein to be located in outer enamel epithelium, regressing enamel organ, secretory ameloblasts, and the dental epithelium connecting the tooth to the oral epithelium at an early eruptive stage. Immunolabelling of transforming growth factor beta-1 (TGF-β1) revealed it to be located close to clusterin. The levels of expression of Clu and Tgfb1 were markedly decreased following in-vivo transfection with anti-miR-214. In contrast, the expression of several genes associated with regulation of growth and development were increased by this treatment. We suggest that clusterin has functions during secretory odontogenesis and the early eruptive phase. Bioinformatic analysis after treatment with anti-miR-214 suggested that, whilst cellular activities associated with tooth mineralization and eruption were inhibited, activities associated with an alternative developmental activity (i.e. biosynthesis of contractile proteins) appeared to be stimulated. These changes probably occur through regulation mediated by a common cluster of transcription factors and support suggestions that microRNAs (miRNAs) are highly significant as regulators of differentiation during odontogenesis. © 2013 Eur J Oral Sci.

  16. AZFa protein DDX3Y is differentially expressed in human male germ cells during development and in testicular tumours: new evidence for phenotypic plasticity of germ cells.

    PubMed

    Gueler, B; Sonne, S B; Zimmer, J; Hilscher, B; Hilscher, W; Græm, N; Rajpert-De Meyts, E; Vogt, P H

    2012-06-01

    DDX3Y (DBY), located within AZoospermia Factor a (AZFa) region of the human Y chromosome (Yq11), encodes a conserved DEAD-box RNA helicase expressed only in germ cells and with a putative function at G1-S phase of the cell cycle. Deletion of AZFa results most often in germ cell aplasia, i.e. Sertoli-cell-only syndrome. To investigate the function of DDX3Y during human spermatogenesis, we examined its expression during development and maturation of the testis and in several types of testicular germ cell tumours (TGCTs), including the pre-invasive carcinoma in situ (CIS) precursor cells which are believed to originate from fetal gonocytes. DDX3Y protein expression was analysed during development in different tissues by western blotting. The localization of DDX3Y in normal fetal and prepubertal testis tissue of different ages as well as in a series of distinct TGCT tissue samples (CIS, classical seminoma, spermatocytic seminoma, teratoma and embryonal carcinoma) was performed by immunohistochemistry. Germ cell-specific expression of DDX3Y protein was revealed in fetal prospermatogonia but not in gonocytes and not before the 17th gestational week. After birth, DDX3Y was expressed at first only in the nuclei of Ap spermatogonia, then also in the cytoplasm similarly to that seen after puberty. In CIS cells, DDX3Y was highly expressed and located predominantly in the nuclei. In invasive TGCT, significant DDX3Y expression was found in seminomas of the classical and spermatocytic type, but not in somatically differentiated non-seminomas, consistent with its germ-cell specific function. The fetal germ cell DDX3Y expression suggests a role in early spermatogonial proliferation and implies that, in men with AZFa deletion, germ cell depletion may begin prenatally. The strong expression of DDX3Y in CIS cells, but not in gonocytes, indicates phenotypic plasticity of CIS cells and suggests partial maturation to spermatogonia, likely due to their postpubertal microenvironment.

  17. Development of interspecies testicular germ-cell transplantation in flatfish.

    PubMed

    Pacchiarini, Tiziana; Sarasquete, Carmen; Cabrita, Elsa

    2014-06-01

    Interspecific testicular germ cell (TGC) transplantation was investigated in two commercial flatfish species. Testes from donor species (Senegalese sole) were evaluated using classical histological techniques (haematoxylin-eosin staining and haematoxylin-light green-orange G-acid fuchsine staining), in situ hybridisation and immunohistochemical analysis. Both Ssvasa1-2 mRNAs and SsVasa protein allowed the characterisation of TGCs, confirming the usefulness of the vasa gene in the detection of Senegalese sole TGCs. Xenogenic transplants were carried out using TGCs from one-year-old Senegalese sole into turbot larvae. Propidium iodide-SYBR-14 and 4',6'-diamidino-2-phenylindole (DAPI) staining showed that 87.98% of the extracted testicular cells were viable for microinjection and that 15.63% of the total recovered cells were spermatogonia. The vasa gene was characterised in turbot recipients using cDNA cloning. Smvasa mRNA was confirmed as a germ cell-specific molecular marker in this species. Smvasa expression analysis during turbot ontogeny was carried out before Senegalese sole TGC transplants into turbot larvae. Turbot larvae at 18 days after hatching (DAH) proved to be susceptible to manipulation procedures. High survival rates (83.75±15.90-100%) were obtained for turbot larvae at 27, 34 and 42 DAH. These data highlight the huge potential of this species for transplantation studies. Quantitative PCR was employed to detect Senegalese sole vasa mRNAs (Ssvasa1-2) in the recipient turbot larvae. The Ssvasa mRNAs showed a significant increase in relative expression in 42-DAH microinjected larvae three weeks after treatment, showing the proliferation of Senegalese sole spermatogonia in transplanted turbot larvae.

  18. Light microscopy and computer three-dimensional reconstruction of the blood capillaries of the enamel organ of rat molar tooth germs

    PubMed Central

    Cerri, Paulo Sérgio; de Faria, Flávio Paulo; Villa, Ricardo Gazoni; Katchburian, Eduardo

    2004-01-01

    We performed a light microscope and a computer three-dimensional reconstruction study of serial sections of the molar enamel organ of 3- and 5-day-old rats perfused with Indian ink through the arterial system. The tooth germs were fixed in Bouin's solution, embedded in paraffin, sectioned and stained with haematoxylin and eosin. For the three-dimensional reconstruction, light micrographs of the serial sections were digitized, and aligned using the serial EM Align software downloaded from http://synapses.bu.edu/tools/. After alignment, the boundaries of the India-ink-filled blood vessels were manually traced with a mouse using the software IGL trace (version 1.26b), also downloaded from the above website. After tracing, a three-dimensional representation of the blood vessel contours was generated in a VRML format and visualized with the help of the software Cortona Web3D viewer (version 4.0) downloaded from http://www.parallelgraphics.com/products/cortona/. Our results showed that in regions where ameloblasts are polarized the capillaries are arranged in three distinct levels: (1) penetrating and leaving capillaries in relation to the outer enamel epithelium; (2) capillaries crossing and branching inside the stellate reticulum; and (3) capillaries branching and anastomosing profusely within the stratum intermedium, thereby forming an extensive capillary plexus intimately associated with the cells of the stratum intermedium. The existence of a conspicuous capillary plexus intermingled with cells of the stratum intermedium, as shown in our results, suggests that some molecules produced by cells of the stratum intermedium could be released into the capillary plexus and thereafter carried to the dental follicle. PMID:15032908

  19. Effect of dental materials calcium hydroxide-containing cement, mineral trioxide aggregate, and enamel matrix derivative on proliferation and differentiation of human tooth germ stem cells.

    PubMed

    Guven, Esra Pamukcu; Yalvac, Mehmet Emir; Sahin, Fikrettin; Yazici, Munevver M; Rizvanov, Albert A; Bayirli, Gunduz

    2011-05-01

    Biocompatibility of pulp capping materials is important for successful use in dentistry. These materials should be nontoxic and permissive for proliferation and induction of odontogenic differentiation of pulp cells. The aim of our study was to evaluate the effects of enamel matrix derivative (EMD), mineral trioxide aggregate (MTA), and calcium hydroxide-containing cement (DYCAL) on proliferation and odontogenic differentiation of human tooth germ stem cells (hTGSCs) in which cells belonging to both pulp tissue and dental follicle exist. The 96-well plates, 24-well plates, and special chamber slides were coated with biomaterials for cell proliferation, differentiation, and scanning electron microscopy analysis. Odontogenic differentiation of hTGSCs was evaluated by analyzing mRNA expression of dentin sialophosphoprotein (DSPP) by real-time polymerase chain reaction expression analysis, measurement of alkaline phosphatase activity, and visualization of calcium depositions by von Kossa staining. Our results demonstrate that EMD is the best material in terms of inducing differentiation and proliferation of hTGSCs. DYCAL was found to be toxic to hTGSCs; however, EMD-coated DYCAL showed less toxicity. EMD-coated MTA was not efficient at inducing proliferation and differentiation. Pulp capping materials come in direct contact with dental pulp cells; thus, they require comprehensive evaluation of interactions between cells and biomaterials. Therefore, we cultured hTGSCs, capable of odontogenic differentiation, on pulp capping materials directly. Our results suggest that combination of capping materials with EMD would increase the quality of capping by increasing biocompatibility of capping materials. Copyright © 2011 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  20. Human germ-line therapy: the case for its development and use.

    PubMed

    Zimmerman, B K

    1991-12-01

    The rationale for pursuing the development and use of germ-line selection and modification techniques is examined in this essay. The argument is put forth that it is the moral obligation of the medical profession to make available to the public any technology that can cure or prevent pathology leading to death and disability, in both the present and future generations. Society should pursue the development of strategies for preventing or correcting, at the germ-line level, genetic features that will lead to, or enhance, pathological conditions. Because prenatal screening and even early embryo screening and selection can prevent only a subset of known genetic disorders, direct genetic intervention is the only way in which certain couples can exercise their rights to reproductive health. Finally, the arguments most often raised against the pursuit of and use of methods for germ-line intervention shall be discussed.

  1. Primary Cilia Integrate Hedgehog and Wnt Signaling during Tooth Development

    PubMed Central

    Liu, B.; Chen, S.; Cheng, D.; Jing, W.; Helms, J.A.

    2014-01-01

    Many ciliopathies have clinical features that include tooth malformations but how these defects come about is not clear. Here we show that genetic deletion of the motor protein Kif3a in dental mesenchyme results in an arrest in odontogenesis. Incisors are completely missing, and molars are enlarged in Wnt1Cre+Kif3afl/fl embryos. Although amelogenesis and dentinogenesis initiate in the molar tooth bud, both processes terminate prematurely. We demonstrate that loss of Kif3a in dental mesenchyme results in loss of Hedgehog signaling and gain of Wnt signaling in this same tissue. The defective dental mesenchyme then aberrantly signals to the dental epithelia, which prompts an up-regulation in the Hedgehog and Wnt responses in the epithelia and leads to multiple attempts at invagination and an expanded enamel organ. Thus, the primary cilium integrates Hedgehog and Wnt signaling between dental epithelia and mesenchyme, and this cilia-dependent integration is required for proper tooth development. PMID:24659776

  2. Primary cilia integrate hedgehog and Wnt signaling during tooth development.

    PubMed

    Liu, B; Chen, S; Cheng, D; Jing, W; Helms, J A

    2014-05-01

    Many ciliopathies have clinical features that include tooth malformations but how these defects come about is not clear. Here we show that genetic deletion of the motor protein Kif3a in dental mesenchyme results in an arrest in odontogenesis. Incisors are completely missing, and molars are enlarged in Wnt1(Cre+)Kif3a(fl/fl) embryos. Although amelogenesis and dentinogenesis initiate in the molar tooth bud, both processes terminate prematurely. We demonstrate that loss of Kif3a in dental mesenchyme results in loss of Hedgehog signaling and gain of Wnt signaling in this same tissue. The defective dental mesenchyme then aberrantly signals to the dental epithelia, which prompts an up-regulation in the Hedgehog and Wnt responses in the epithelia and leads to multiple attempts at invagination and an expanded enamel organ. Thus, the primary cilium integrates Hedgehog and Wnt signaling between dental epithelia and mesenchyme, and this cilia-dependent integration is required for proper tooth development.

  3. DDX4 (VASA) is conserved in germ cell development in marsupials and monotremes.

    PubMed

    Hickford, Danielle E; Frankenberg, Stephen; Pask, Andrew J; Shaw, Geoff; Renfree, Marilyn B

    2011-10-01

    DDX4 (VASA) is an RNA helicase expressed in the germ cells of all animals. To gain greater insight into the role of this gene in mammalian germ cell development, we characterized DDX4 in both a marsupial (the tammar wallaby) and a monotreme (the platypus). DDX4 is highly conserved between eutherian, marsupial, and monotreme mammals. DDX4 protein is absent from tammar fetal germ cells but is present from Day 1 postpartum in both sexes. The distribution of DDX4 protein during oogenesis and spermatogenesis in the tammar is similar to eutherians. Female tammar germ cells contain DDX4 protein throughout all stages of postnatal oogenesis. In males, DDX4 is in gonocytes, and during spermatogenesis it is present in spermatocytes and round spermatids. A similar distribution of DDX4 occurs in the platypus during spermatogenesis. There are several DDX4 isoforms in the tammar, resulting from both pre- and posttranslational modifications. DDX4 in marsupials and monotremes has multiple splice variants and polyadenylation motifs. Using in silico analyses of genomic databases, we found that these previously unreported splice variants also occur in eutherians. In addition, several elements implicated in the control of Ddx4 expression in the mouse, including RGG (arginine-glycine-glycine) and dimethylation of arginine motifs and CpG islands within the Ddx4 promoter, are also highly conserved. Collectively these data suggest that DDX4 is essential for the regulation of germ cell proliferation and differentiation across all three extant mammalian groups-eutherians, marsupials, and monotremes.

  4. Temporal germ cell development strategy during continuous spermatogenesis within the montane lizard, Sceloporus bicanthalis (Squamata; Phrynosomatidae).

    PubMed

    Gribbins, Kevin; Anzalone, Marla; Collier, Matthew; Granados-González, Gisela; Villagrán-Santa Cruz, Maricela; Hernández-Gallegos, Oswaldo

    2011-10-01

    Sceloporus bicanthalis is a viviparous lizard that lives at higher elevations in Mexico. Adult male S. bicanthalis were collected (n = 36) from the Nevado de Toluca, Mexico (elevation is 4200 m) during August to December, 2007 and January to July, 2008. Testes were extracted, fixed in Trumps, and dehydrated in a graded series of ethanol. Tissues were embedded, sectioned (2 μm), stained, and examined via a light microscope to determine the spermatogenic developmental strategy of S. bicanthalis. In all months examined, the testes were spermiogenically active; based on this, plus the presence of sperm in the lumina of seminiferous tubules, we inferred that S. bicanthalis had year-round or continuous spermatogenesis, unlike most reptiles that occupy a temperate or montane habitat. It was recently reported that seasonally breeding reptiles had a temporal germ cell development strategy similar to amphibians, where germ cells progress through spermatogenesis as a single population, which leads to a single spermiation event. This was much different than spatial development within the testis of other derived amniotes. We hypothesized that germ cell development was temporal in S. bicanthalis. Therefore, we wanted to determine whether reptiles that practice continuous spermatogenesis have a mammalian-like spatial germ cell development, which is different than the typical temperate reptile exhibiting a temporal development. In the present study, S. bicanthalis had a temporal development strategy, despite its continuous spermatogenic cycle, making them similar to tropical anoles.

  5. The function and regulation of vasa-like genes in germ-cell development

    PubMed Central

    Raz, Erez

    2000-01-01

    The vasa gene, essential for germ-cell development, was originally identified in Drosophila, and has since been found in other invertebrates and vertebrates. Analysis of these vasa homologs has revealed a highly conserved role for Vasa protein among different organisms, as well as some important differences in its regulation. PMID:11178242

  6. Germ cell development in the scleractinian coral Euphyllia ancora (Cnidaria, Anthozoa).

    PubMed

    Shikina, Shinya; Chen, Chieh-Jhen; Liou, Jhe-Yu; Shao, Zi-Fan; Chung, Yi-Jou; Lee, Yan-Horn; Chang, Ching-Fong

    2012-01-01

    Sexual reproduction of scleractinian coral is among the most important means of establishing coral populations. However, thus far, little is known about the mechanisms underlying coral gametogenesis. To better understand coral germ cell development, we performed a histological analysis of gametogenesis in Euphyllia ancora and characterized the coral homolog of the Drosophila germline marker gene vasa. The histological analysis revealed that E. ancora gametogenesis occurs in the mesenterial mesoglea between the mesenterial filaments and the retractor muscle bands. The development of germ cells takes approximately one year in females and half a year in males. Staining of tissue sections with an antibody against E. ancora Vasa (Eavas) revealed anti-Eavas immunoreactivity in the oogonia, early oocyte, and developing oocyte, but only faint or undetectable reactivity in developing oocytes that were >150 µm in diameters. In males, Eavas could be detected in the spermatogonia and primary spermatocytes but was only faintly detectable in the secondary spermatocytes, spermatids, and sperms. Furthermore, a reverse transcription-polymerase chain reaction analysis and Western blotting analysis of unfertilized mature eggs proved the presence of Eavas transcripts and proteins, suggesting that Eavas may be a maternal factor. Vasa may represent a germ cell marker for corals, and would allow us to distinguish germ cells from somatic cells in coral bodies that have no distinct organs.

  7. Germ Cell Development in the Scleractinian Coral Euphyllia ancora (Cnidaria, Anthozoa)

    PubMed Central

    Shikina, Shinya; Chen, Chieh-Jhen; Liou, Jhe-Yu; Shao, Zi-Fan; Chung, Yi-Jou; Lee, Yan-Horn; Chang, Ching-Fong

    2012-01-01

    Sexual reproduction of scleractinian coral is among the most important means of establishing coral populations. However, thus far, little is known about the mechanisms underlying coral gametogenesis. To better understand coral germ cell development, we performed a histological analysis of gametogenesis in Euphyllia ancora and characterized the coral homolog of the Drosophila germline marker gene vasa. The histological analysis revealed that E. ancora gametogenesis occurs in the mesenterial mesoglea between the mesenterial filaments and the retractor muscle bands. The development of germ cells takes approximately one year in females and half a year in males. Staining of tissue sections with an antibody against E. ancora Vasa (Eavas) revealed anti-Eavas immunoreactivity in the oogonia, early oocyte, and developing oocyte, but only faint or undetectable reactivity in developing oocytes that were >150 µm in diameters. In males, Eavas could be detected in the spermatogonia and primary spermatocytes but was only faintly detectable in the secondary spermatocytes, spermatids, and sperms. Furthermore, a reverse transcription-polymerase chain reaction analysis and Western blotting analysis of unfertilized mature eggs proved the presence of Eavas transcripts and proteins, suggesting that Eavas may be a maternal factor. Vasa may represent a germ cell marker for corals, and would allow us to distinguish germ cells from somatic cells in coral bodies that have no distinct organs. PMID:22848529

  8. Cellular and molecular mechanisms of tooth root development.

    PubMed

    Li, Jingyuan; Parada, Carolina; Chai, Yang

    2017-02-01

    The tooth root is an integral, functionally important part of our dentition. The formation of a functional root depends on epithelial-mesenchymal interactions and integration of the root with the jaw bone, blood supply and nerve innervations. The root development process therefore offers an attractive model for investigating organogenesis. Understanding how roots develop and how they can be bioengineered is also of great interest in the field of regenerative medicine. Here, we discuss recent advances in understanding the cellular and molecular mechanisms underlying tooth root formation. We review the function of cellular structure and components such as Hertwig's epithelial root sheath, cranial neural crest cells and stem cells residing in developing and adult teeth. We also highlight how complex signaling networks together with multiple transcription factors mediate tissue-tissue interactions that guide root development. Finally, we discuss the possible role of stem cells in establishing the crown-to-root transition, and provide an overview of root malformations and diseases in humans. © 2017. Published by The Company of Biologists Ltd.

  9. Dental development and tooth agenesis in children with velocardiofacial syndrome.

    PubMed

    Heliövaara, Arja; Rantanen, Irma; Arte, Sirpa

    2011-11-01

    BACKGROUND. Variations in dental development and tooth agenesis have been reported in children with velocardiofacial syndrome (VCFS). AIM. The aim was to evaluate the dental development and missing permanent teeth in children with VCFS. DESIGN. Forty-five children (23 girls) with VCFS who had visited the cleft palate and craniofacial centre were studied retrospectively from orthopantomograms taken at the mean age of 7.9 years (range 5.8-12.9). Thirteen of the children with VCFS had palatal clefts. The deletion of 22q11 was verified by FISH techniques. The dental stages were assessed by the method of Demirjian, and the dental age was calculated according to the Finnish dental maturity reference values. A paired Student's t-test was used in the statistical analysis. RESULTS. Eight children (17%), four with palatal clefts, had tooth agenesis. Four children (9%) had agenesis of mandibular incisors. The missing teeth (n = 19) were mainly mandibular incisors (n = 6), maxillary lateral incisors (n = 2), and maxillary second premolars (n = 4). The dental age of the children with VCFS was not different from their chronological age, but there was great individual variation. CONCLUSIONS. A high prevalence of missing permanent teeth, especially mandibular incisors, was observed. The need for thorough clinical and radiological dental examination in children with VCFS is emphasized. © 2011 The Authors. International Journal of Paediatric Dentistry © 2011 BSPD, IAPD and Blackwell Publishing Ltd.

  10. Expression of dynamin II in odontoblast during mouse tooth development.

    PubMed

    Oh, Jong-Hwa; Choi, Baik-Dong; Park, Jin-Ju; Jeong, Soon-Jeong; Kim, Jin-Soo; Kim, Jae-Duk; Lim, Do-Seon; Kim, Byung-Hoon; Cho, Yong-Ick; Jeong, Moon-Jin

    2011-08-01

    Odontoblasts secrete a collagen-based matrix and release numerous membrane-bound matrix vesicles, which are involved in dentin formation during tooth development. Dynamin II is a GTPase protein that contributes a variety of vesicular budding events, such as endocytotic membrane fission, caveolae internalization and protein trafficking in the Golgi apparatus. However, the expression and function of dynamin II in odontoblasts has not been reported. Therefore, this study examined the expression and possible role of dynamin II in odontoblasts during tooth development and mineralization. The levels of mRNA and protein expression in MDPC23 cells were significantly high at the early stages of differentiation and then decreased gradually thereafter. Immunohistochemistry showed that dynamin II was not expressed near the region of the odontoblasts at embryonic day 17 (E17) and E21. However, dynamin II was expressed strongly in the odontoblast layer at postnatal day 1 (PN1) and decreased gradually at PN3 and PN5. In addition, at PN15 in the functional stage, the dynamin II protein was also expressed in the odontoblast process as well as adjacent to the nuclear region. In conclusion, dynamin II may be involved in the transport of vesicles containing collageneous and non-collageneous proteins for dentin formation in odontoblast, suggesting that it is a good nanomolecule as a candidate to regulate the secretion of collagen on the bone and other nano material.

  11. Pulp Vascularization during Tooth Development, Regeneration, and Therapy.

    PubMed

    Rombouts, C; Giraud, T; Jeanneau, C; About, I

    2017-02-01

    The pulp is a highly vascularized tissue situated in an inextensible environment surrounded by rigid dentin walls, with the apical foramina being the only access. The pulp vascular system is not only responsible for nutrient supply and waste removal but also contributes actively to the pulp inflammatory response and subsequent regeneration. This review discusses the underlying mechanisms of pulp vascularization during tooth development, regeneration, and therapeutic procedures, such as tissue engineering and tooth transplantation. Whereas the pulp vascular system is established by vasculogenesis during embryonic development, sprouting angiogenesis is the predominant process during regeneration and therapeutic processes. Hypoxia can be considered a common driving force. Dental pulp cells under hypoxic stress release proangiogenic factors, with vascular endothelial growth factor being one of the most potent. The benefit of exogenous vascular endothelial growth factor application in tissue engineering has been well demonstrated. Interestingly, dental pulp stem cells have an important role in pulp revascularization. Indeed, recent studies show that dental pulp stem cell secretome possesses angiogenic potential that actively contributes to the angiogenic process by guiding endothelial cells and even by differentiating themselves into the endothelial lineage. Although considerable insight has been obtained in the processes underlying pulp vascularization, many questions remain relating to the signaling pathways, timing, and influence of various stress conditions.

  12. Gonadal status of male recipient mice influences germ cell development in immature buffalo testis tissue xenograft.

    PubMed

    Reddy, Niranjan; Mahla, Ranjeet Singh; Thathi, Revanth; Suman, Sanjay Kumar; Jose, Jedy; Goel, Sandeep

    2012-01-01

    Growth and development of immature testis xenograft from various domestic mammals has been shown in mouse recipients; however, buffalo testis xenografts have not been reported to date. In this study, small fragments of testis tissue from 8-week-old buffalo calves were implanted subcutaneously onto the back of immunodeficient male mouse recipients, which were either castrated or left intact (non-castrated). The xenografts were retrieved and analyzed 12 and 24 weeks later. The grafted tissue survived and grew in both types of recipient with a significant increase in weight and seminiferous tubule diameter. Recovery of grafts from intact recipients 24 weeks post-grafting was significantly lower than that from the castrated recipients. Seminal vesicle indices and serum testosterone levels were lower in castrated recipients at both collection time points in comparison to the intact recipients and non-grafted intact mouse controls. Pachytene spermatocytes were the most advanced germ cells observed in grafts recovered from castrated recipients 24 weeks post-grafting. Complete spermatogenesis, as indicated by the presence of elongated spermatids, was present only in grafts from intact recipients collected 24 weeks post-grafting. However, significant number of germ cells with DNA damage was also detected in these grafts as indicated by TUNEL assay. The complete germ cell differentiation in xenografts from intact recipients may be attributed to efficient Sertoli cell maturation. These results suggest that germ cell differentiation in buffalo testis xenograft can be completed by altering the recipient gonadal status.

  13. Arginine methylation of SmB is required for Drosophila germ cell development.

    PubMed

    Anne, Joël

    2010-09-01

    Sm proteins constitute the common core of spliceosomal small nuclear ribonucleoproteins. Although Sm proteins are known to be methylated at specific arginine residues within the C-terminal arginine-glycine dipeptide (RG) repeats, the biological relevance of these modifications remains unknown. In this study, a tissue-specific function of arginine methylation of the SmB protein was identified in Drosophila. Analysis of the distribution of SmB during oogenesis revealed that this protein accumulates at the posterior pole of the oocyte, a cytoplasmic region containing the polar granules, which are necessary for the formation of primordial germ cells. The pole plasm localisation of SmB requires the methylation of arginine residues in its RG repeats by the Capsuléen-Valois methylosome complex. Functional studies showed that the methylation of these arginine residues is essential for distinct processes of the germline life cycle, including germ cell formation, migration and differentiation. In particular, the methylation of a subset of these arginine residues appears essential for the anchoring of the polar granules at the posterior cortex of the oocyte, whereas the methylation of another subset controls germ cell migration during embryogenesis. These results demonstrate a crucial role of arginine methylation in directing the subcellular localisation of SmB and that this modification contributes specifically to the establishment and development of germ cells.

  14. Germ line determinants are not localized early in sea urchin development, but do accumulate in the small micromere lineage.

    PubMed

    Juliano, Celina E; Voronina, Ekaterina; Stack, Christie; Aldrich, Maryanna; Cameron, Andrew R; Wessel, Gary M

    2006-12-01

    Two distinct modes of germ line determination are used throughout the animal kingdom: conditional-an inductive mechanism, and autonomous-an inheritance of maternal factors in early development. This study identifies homologs of germ line determinants in the sea urchin Strongylocentrotus purpuratus to examine its mechanism of germ line determination. A list of conserved germ-line associated genes from diverse organisms was assembled to search the S. purpuratus genome for homologs, and the expression patterns of these genes were examined during embryogenesis by whole mount in situ RNA hybridization and QPCR. Of the 14 genes tested, all transcripts accumulate uniformly during oogenesis and Sp-pumilio, Sp-tudor, Sp-MSY, and Sp-CPEB1 transcripts are also uniformly distributed during embryonic development. Sp-nanos2, Sp-seawi, and Sp-ovo transcripts, however, are enriched in the vegetal plate of the mesenchyme blastula stage and Sp-vasa, Sp-nanos2, Sp-seawi, and Sp-SoxE transcripts are localized in small micromere descendents at the tip of the archenteron during gastrulation and are then enriched in the left coelomic pouch of larvae. The results of this screen suggest that sea urchins conditionally specify their germ line, and support the hypothesis that this mechanism is the basal mode of germ line determination amongst deuterostomes. Furthermore, accumulation of germ line determinants selectively in small micromere descendents supports the hypothesis that these cells contribute to the germ line.

  15. Dynamic changes in DNA modification states during late gestation male germ line development in the rat

    PubMed Central

    2014-01-01

    Background Epigenetic reprogramming of fetal germ cells involves the genome-wide erasure and subsequent re-establishment of DNA methylation. Mouse studies indicate that DNA demethylation may be initiated at embryonic day (e) 8 and completed between e11.5 and e12.5. In the male germline, DNA remethylation begins around e15 and continues for the remainder of gestation whilst this process occurs postnatally in female germ cells. Although 5-methylcytosine (5mC) dynamics have been extensively characterised, a role for the more recently described DNA modifications (5-hydroxymethylcytosine (5hmC), 5-formylcytosine (5fC) and 5-carboxylcytosine (5caC)) remains unclear. Moreover, the extent to which the developmental dynamics of 5mC reprogramming is conserved across species remains largely undetermined. Here, we sought to describe this process during late gestation in the male rat. Results Using immunofluorescence, we demonstrate that 5mC is re-established between e18.5 and e21.5 in the rat, subsequent to loss of 5hmC, 5fC and 5caC, which are present in germ cells between e14.5 and e16.5. All of the evaluated DNA methyl forms were expressed in testicular somatic cells throughout late gestation. 5fC and 5caC can potentially be excised through Thymine DNA Glycosylase (TDG) and repaired by the base excision repair (BER) pathway, implicating 5mC oxidation in active DNA demethylation. In support of this potential mechanism, we show that TDG expression is coincident with the presence of 5hmC, 5fC and 5caC in male germ cell development. Conclusion The developmental dependent changes in germ cell DNA methylation patterns suggest that they are linked with key stages of male rat germline progression. PMID:25225576

  16. Easy assessment of ES cell clone potency for chimeric development and germ-line competency by an optimized aggregation method.

    PubMed

    Kondoh, G; Yamamoto, Y; Yoshida, K; Suzuki, Y; Osuka, S; Nakano, Y; Morita, T; Takeda, J

    1999-05-13

    Production of germ-line competent chimeric mice from embryonic stem (ES) cells is an inevitable step in establishing gene-manipulated mouse lineages. A common method used for creating chimeric mice is the injection of ES cells into the blastocoelic cavity (blastocyst injection). The aggregation method is an alternative way to introduce ES cells to the host embryo which is less difficult than blastocyst injection. Here we re-examined the condition of embryo-ES cell coculture on the aggregation method and found improvement of germ-line competent chimeric production by a simple modification of the coculture medium. Moreover, R1 ES cell and its 10 gene-manipulated subclones were tested by this method. Although all ES cell clones showed good morphology and a normal karyotype, the efficiency of chimeric development and germ-line transmission varied among clones and were classified into three grades according to germ-line competency. In the first group (class A), both the incidence of chimera with high ES cell contribution and the rate of germ-line transmission were fairly high. Germ-line competent chimeras were obtained but with rather low efficiency in the second group (class B), while another group (class C) showed an absence of high ES cell-contributed chimeras and no germ-line transmission. These results suggest the usefulness of this modified aggregation method to predict the potency of ES cell clones for germ-line competency.

  17. Germline development in amniotes: A paradigm shift in primordial germ cell specification

    PubMed Central

    2016-01-01

    In the field of germline development in amniote vertebrates, primordial germ cell (PGC) specification in birds and reptiles remains controversial. Avians are believed to adopt a predetermination or maternal specification mode of PGC formation, contrary to an inductive mode employed by mammals and, supposedly, reptiles. Here, we revisit and review some key aspects of PGC development that channelled the current subdivision, and challenge the position of birds and reptiles as well as the ‘binary’ evolutionary model of PGC development in vertebrates. We propose an alternative view on PGC specification where germ plasm plays a role in laying the foundation for the formation of PGC precursors (pPGC), but not necessarily of PGCs. Moreover, inductive mechanisms may be necessary for the transition from pPGCs to PGCs. Within this framework, the implementation of data from birds and reptiles could provide new insights on the evolution of PGC specification in amniotes. PMID:27273724

  18. [Role of GAGA Factor in Drosophila Primordial Germ Cell Migration and Gonad Development].

    PubMed

    Dorogova, N V; Khrushcheva, A S; Fedorova, E V; Ogienko, A A; Baricheva, E M

    2016-01-01

    The GAGA protein of drosophila is a factor involved in epigenetic transcription regulation of a large gene group controlling developmental processes. In this paper, the role of GAGA factor in germ cell migration is demonstrated as well as its effect on the gonad development in drosophila embryogenesis. Mutations in the Trl gene, encoding GAGA factor, prematurely induces the active migration program and relocation of the primordial cells inward the embryo before the beginning of gastrulation. The germ cells that prematurely separated from the main group migrate ectopically, lose orientation, and stay out of gonad development. Expression pattern of the Trl gene suggests its activity in epithelial cells of the embryonic blastoderm, part of which contact primordial cells. Thus, GAGA factor influences migration of these cells in an indirect manner via their somatic environment.

  19. Critical period of nonpromoter DNA methylation acquisition during prenatal male germ cell development.

    PubMed

    Niles, Kirsten M; Chan, Donovan; La Salle, Sophie; Oakes, Christopher C; Trasler, Jacquetta M

    2011-01-01

    The prenatal period of germ cell development is a key time of epigenetic programming in the male, a window of development that has been shown to be influenced by maternal factors such as dietary methyl donor supply. DNA methylation occurring outside of promoter regions differs significantly between sperm and somatic tissues and has recently been linked with the regulation of gene expression during development as well as successful germline development. We examined DNA methylation at nonpromoter, intergenic sequences in purified prenatal and postnatal germ cells isolated from wildtype mice and mice deficient in the DNA methyltransferase cofactor DNMT3L. Erasure of the parental DNA methylation pattern occurred by 13.5 days post coitum (dpc) with the exception of approximately 8% of loci demonstrating incomplete erasure. For most loci, DNA methylation acquisition occurred between embryonic day 13.5 to 16.5 indicating that the key phase of epigenetic pattern establishment for intergenic sequences in male germ cells occurs prior to birth. In DNMT3L-deficient germ cells at 16.5 dpc, average DNA methylation levels were low, about 30% of wildtype levels; however, by postnatal day 6, about half of the DNMT3L deficiency-specific hypomethylated loci had acquired normal methylation levels. Those loci normally methylated earliest in the prenatal period were the least affected in the DNMT3L-deficient mice, suggesting that some loci may be more susceptible than others to perturbations occurring prenatally. These results indicate that the critical period of DNA methylation programming of nonpromoter, intergenic sequences occurs in male germline progenitor cells in the prenatal period, a time when external perturbations of epigenetic patterns could result in diminished fertility.

  20. Development of a multi-layered virtual tooth model for the haptic dental training system.

    PubMed

    Yoshida, Yoshinori; Yamaguchi, Satoshi; Kawamoto, Yusuke; Noborio, Hiroshi; Murakami, Shinya; Sohmura, Taiji

    2011-01-01

    A virtual reality (VR) haptic dental training system could be a promising tool for future dental education. One major challenge is to develop a virtual tooth model which similarly reflected a real tooth having multiple layers with different mechanical hardness in each layer. The multi-layered virtual tooth model was successfully constructed in our virtual system. The constructed model allows us to feel tooth cutting which is similar to that with a real tooth. Through a cutting experiment by using the real tooth, a spring coefficient and a damping coefficient of a dental hard tissue were determined 0.8 N/mm and 1.79 Nsec/mm respectively. The feedback force smoothly altered when crossing the border of regions having different mechanical hardnesses. The constructed model introduced in this study could be a promising tool for acquiring dental hand skills in a virtual learning system.

  1. Beta-Catenin and Plakoglobin Expression during Zebrafish Tooth Development and Replacement.

    PubMed

    Verstraeten, Barbara; van Hengel, Jolanda; Huysseune, Ann

    2016-01-01

    We analyzed the protein distribution of two cadherin-associated molecules, plakoglobin and β-catenin, during the different stages of tooth development and tooth replacement in zebrafish. Plakoglobin was detected at the plasma membrane already at the onset of tooth development in the epithelial cells of the tooth. This pattern remained unaltered during further tooth development. The mesenchymal cells only showed plakoglobin from cytodifferentiation onwards. Plakoglobin 1a morpholino-injected embryos showed normal tooth development with proper initiation and differentiation. Although plakoglobin is clearly present during normal odontogenesis, the loss of plakoglobin 1a does not influence tooth development. β-catenin was found at the cell borders of all cells of the successional lamina but also in the nuclei of surrounding mesenchymal cells. Only membranous, not nuclear, β-catenin, was found during morphogenesis stage. However, during cytodifferentiation stage, both nuclear and membrane-bound β-catenin was detected in the layers of the enamel organ as well as in the differentiating odontoblasts. Nuclear β-catenin is an indication of an activated Wnt pathway, therefore suggesting a possible role for Wnt signalling during zebrafish tooth development and replacement.

  2. Beta-Catenin and Plakoglobin Expression during Zebrafish Tooth Development and Replacement

    PubMed Central

    Verstraeten, Barbara; van Hengel, Jolanda; Huysseune, Ann

    2016-01-01

    We analyzed the protein distribution of two cadherin-associated molecules, plakoglobin and β-catenin, during the different stages of tooth development and tooth replacement in zebrafish. Plakoglobin was detected at the plasma membrane already at the onset of tooth development in the epithelial cells of the tooth. This pattern remained unaltered during further tooth development. The mesenchymal cells only showed plakoglobin from cytodifferentiation onwards. Plakoglobin 1a morpholino-injected embryos showed normal tooth development with proper initiation and differentiation. Although plakoglobin is clearly present during normal odontogenesis, the loss of plakoglobin 1a does not influence tooth development. β-catenin was found at the cell borders of all cells of the successional lamina but also in the nuclei of surrounding mesenchymal cells. Only membranous, not nuclear, β-catenin, was found during morphogenesis stage. However, during cytodifferentiation stage, both nuclear and membrane-bound β-catenin was detected in the layers of the enamel organ as well as in the differentiating odontoblasts. Nuclear β-catenin is an indication of an activated Wnt pathway, therefore suggesting a possible role for Wnt signalling during zebrafish tooth development and replacement. PMID:26938059

  3. Development of transplanted pulp tissue containing epithelial sheath into a tooth-like structure.

    PubMed

    Lyaruu, D M; van Croonenburg, E J; van Duin, M A; Bervoets, T J; Wöltgens, J H; de Blieck-Hogervorst, J M

    1999-08-01

    The aim of these studies was to find out whether intact neonatal pulp tissue containing residual epithelial cells can induce the development of a tooth-like structure in situ. First maxillary neonatal hamster molar pulps containing adhering undifferentiated epithelial cells were transplanted submucosally in the oral cavity of recipient mothers for periods ranging from 2-8 weeks and the tissues were then processed for light microscopy. Developing tooth-like structures containing mineralised tubular dentine, predentine and a vascularised pulp-like chamber lined with functional odontoblast-like cells were observed in the specimens within 2 weeks of transplantation. Enamel and root formation were not observed. These data indicate that neonatal dental pulp tissues containing epithelial cell remnants have the capacity to develop into tooth-like structures and that this could be the explanation for the development of tooth-like structures sometimes observed in infants after extraction of a natal tooth.

  4. Continuous spermatogenesis and the germ cell development strategy within the testis of the Jamaican Gray Anole, Anolis lineatopus.

    PubMed

    Gribbins, K M; Rheubert, J L; Poldemann, E H; Collier, M H; Wilson, B; Wolf, K

    2009-09-01

    Testicular tissues from Anolis lineatopus were examined histologically to determine testicular structure, germ cell morphologies, and the germ cell development strategy employed during spermatogenesis. Anoles (N=36) were collected from southern Jamaica from October 2004 to September 2005. Testes were extracted and fixed in Trump's fixative, dehydrated, embedded in Spurr's plastic, sectioned, and stained with basic fuchsin/toluidine blue. The testes of Jamaican Anoles were composed of seminiferous tubules lined with seminiferous epithelia, similar to birds and mammals, and were spermatogenically active during every month of the year. However, spermatogenic activity fluctuated based on morphometric data for February, May and June, and September-December. Sequential increases for these months and decreases in between months in tubular diameters and epithelial heights were due to fluctuations in number of elongating spermatids and spermiation events. Cellular associations were not observed during spermatogenesis in A. lineatopus, and three or more spermatids coincided with mitotic and meiotic cells within the seminiferous epithelium. Although the germ cell generations were layered within the seminiferous epithelium, similar to birds and mammals, the actual temporal development of germ cells and bursts of sperm release more closely resembled that reported recently for other reptilian taxa. All of these reptiles were temperate species that showed considerable seasonality in terms of testis morphology and spermatogenesis. The Jamaican Gray Anole has continuous spermatogenesis yet maintains this temporal germ cell development pattern. Thus, a lack of seasonal spermatogenesis in this anole seems to have no influence on the germ cell development strategy employed during sperm development.

  5. Development of in vitro tooth staining model and usage of catalysts to elevate the effectiveness of tooth bleaching.

    PubMed

    Lee, Bor-Shiunn; Huang, Shih-Hao; Chiang, Yu-Chih; Chien, Yu-Shan; Mou, Chung-Yuan; Lin, Chun-Pin

    2008-01-01

    Whole blood or tea was frequently used to stain the teeth for measuring the effectiveness of different bleaching materials. However, the components of blood or tea cannot be quantitatively determined and variability might exist among different brands of tea. The purpose of this study was to develop a reproducible in vitro tooth-staining model to simulate the intrinsic discoloration of teeth and evaluate the ability of two catalysts to enhance the bleaching activity of H(2)O(2). Rhodamine B, Orange II, Fe(III) phthalocyanine, and tea were used to stain the tooth specimens for 4-72 h and subsequently bleached by H(2)O(2) for 4-72 h. The process was photographed using a digital stereoscopic microscope and a digital camera. The image was transformed to get L*, a*, b* values of CIE Lab system with image processing software. The catalytic ability of light irradiation plus addition of Fe/Sodium-Y or Mn/Sodium-Y for specimens stained by Orange II was evaluated in test tubes and in extracted tooth model. The color of specimens stained by Rhodamine B could not be sufficiently recovered after bleaching by H(2)O(2). In addition, the reaction of Fe(III) phthalocyanine with H(2)O(2) in test tubes was too fast to be monitored. Light activation plus use of Fe/Sodium-Y or Mn/Sodium-Y could significantly accelerate the bleaching efficiency of H(2)O(2). Orange II was the most appropriate dye for tooth staining among the dyes used in this study. Addition of Fe/Sodium-Y or Mn/Sodium-Y plus light irradiation could elevate the bleaching efficacy of H(2)O(2) for those specimens stained by Orange II.

  6. Fully functional bioengineered tooth replacement as an organ replacement therapy

    PubMed Central

    Ikeda, Etsuko; Morita, Ritsuko; Nakao, Kazuhisa; Ishida, Kentaro; Nakamura, Takashi; Takano-Yamamoto, Teruko; Ogawa, Miho; Mizuno, Mitsumasa; Kasugai, Shohei; Tsuji, Takashi

    2009-01-01

    Current approaches to the development of regenerative therapies have been influenced by our understanding of embryonic development, stem cell biology, and tissue engineering technology. The ultimate goal of regenerative therapy is to develop fully functioning bioengineered organs which work in cooperation with surrounding tissues to replace organs that were lost or damaged as a result of disease, injury, or aging. Here, we report a successful fully functioning tooth replacement in an adult mouse achieved through the transplantation of bioengineered tooth germ into the alveolar bone in the lost tooth region. We propose this technology as a model for future organ replacement therapies. The bioengineered tooth, which was erupted and occluded, had the correct tooth structure, hardness of mineralized tissues for mastication, and response to noxious stimulations such as mechanical stress and pain in cooperation with other oral and maxillofacial tissues. This study represents a substantial advance and emphasizes the potential for bioengineered organ replacement in future regenerative therapies. PMID:19666587

  7. Fully functional bioengineered tooth replacement as an organ replacement therapy.

    PubMed

    Ikeda, Etsuko; Morita, Ritsuko; Nakao, Kazuhisa; Ishida, Kentaro; Nakamura, Takashi; Takano-Yamamoto, Teruko; Ogawa, Miho; Mizuno, Mitsumasa; Kasugai, Shohei; Tsuji, Takashi

    2009-08-11

    Current approaches to the development of regenerative therapies have been influenced by our understanding of embryonic development, stem cell biology, and tissue engineering technology. The ultimate goal of regenerative therapy is to develop fully functioning bioengineered organs which work in cooperation with surrounding tissues to replace organs that were lost or damaged as a result of disease, injury, or aging. Here, we report a successful fully functioning tooth replacement in an adult mouse achieved through the transplantation of bioengineered tooth germ into the alveolar bone in the lost tooth region. We propose this technology as a model for future organ replacement therapies. The bioengineered tooth, which was erupted and occluded, had the correct tooth structure, hardness of mineralized tissues for mastication, and response to noxious stimulations such as mechanical stress and pain in cooperation with other oral and maxillofacial tissues. This study represents a substantial advance and emphasizes the potential for bioengineered organ replacement in future regenerative therapies.

  8. Germ cell differentiation and proliferation in the developing testis of the South American plains viscacha, Lagostomus maximus (Mammalia, Rodentia).

    PubMed

    Gonzalez, C R; Muscarsel Isla, M L; Fraunhoffer, N A; Leopardo, N P; Vitullo, A D

    2012-08-01

    Cell proliferation and cell death are essential processes in the physiology of the developing testis that strongly influence the normal adult spermatogenesis. We analysed in this study the morphometry, the expression of the proliferation cell nuclear antigen (PCNA), cell pluripotency marker OCT-4, germ cell marker VASA and apoptosis in the developing testes of Lagostomus maximus, a rodent in which female germ line develops through abolished apoptosis and unrestricted proliferation. Morphometry revealed an increment in the size of the seminiferous cords with increasing developmental age, arising from a significant increase of PCNA-positive germ cells and a stable proportion of PCNA-positive Sertoli cells. VASA showed a widespread cytoplasmic distribution in a great proportion of proliferating gonocytes that increased significantly at late development. In the somatic compartment, Leydig cells increased at mid-development, whereas peritubular cells showed a stable rate of proliferation. In contrast to other mammals, OCT-4 positive gonocytes increased throughout development reaching 90% of germ cells in late-developing testis, associated with a conspicuous increase in circulating FSH from mid- to late-gestation. TUNEL analysis was remarkable negative, and only a few positive cells were detected in the somatic compartment. These results show that the South American plains viscacha displays a distinctive pattern of testis development characterized by a sustained proliferation of germ cells throughout development, with no signs of apoptosis cell demise, in a peculiar endocrine in utero ambiance that seems to promote the increase of spermatogonial number as a primary direct effect of FSH.

  9. RNA Granules in Germ Cells

    PubMed Central

    Voronina, Ekaterina; Seydoux, Geraldine; Sassone-Corsi, Paolo; Nagamori, Ippei

    2011-01-01

    Germ granules” are cytoplasmic, nonmembrane-bound organelles unique to germline. Germ granules share components with the P bodies and stress granules of somatic cells, but also contain proteins and RNAs uniquely required for germ cell development. In this review, we focus on recent advances in our understanding of germ granule assembly, dynamics, and function. One hypothesis is that germ granules operate as hubs for the posttranscriptional control of gene expression, a function at the core of the germ cell differentiation program. PMID:21768607

  10. A perspective on the evolution of germ-cell development and germinal mosaics of deleterious mutations.

    PubMed

    Woodruff, Ronny C; Balinski, Michael A; Bouzat, Juan L

    2015-10-01

    In many animals a small number of primordial germ cells (PGCs) are set aside early in development, mitosis and mitochondrial DNA syntheses are arrested, transcription is stopped or reduced, and the PGCs migrate later to the emerging gonads and become germ cells. What could be the evolutionary advantage of sequestering non-dividing PGCs early in development? A commonly cited advantage is a reduction in the number of new deleterious mutations that would occur if there were additional divisions in PGCs early in development. We would like to add to this advantage the fact that these additional mutations in PGCs give rise to germinal mosaics (i.e., premeiotic clusters of mutation) in multiple progeny of the same individual, thus having a larger detrimental effect on the evolutionary fitness of their carriers. Here, we reviewed published studies providing evidence that germinal mosaics of deleterious mutant alleles are not rare, occur for all types of genetic damage, and have been observed in all tested organisms and in nature. We propose the hypothesis that PGC sequestration during early animal development may have evolved in part in response to selection for preventing the occurrence of premeiotic clusters of deleterious mutant alleles, and describe a series of predictions that would allow the assessment of the potential role of germinal mosaics on the evolution of PGC sequestration.

  11. From primordial germ cells to primordial follicles: a review and visual representation of early ovarian development in mice.

    PubMed

    Wear, Hannah M; McPike, Matthew J; Watanabe, Karen H

    2016-06-21

    Normal development of reproductive organs is crucial for successful reproduction. In mice the early ovarian developmental process occurs during the embryonic and postnatal period and is regulated through a series of molecular signaling events. Early ovarian development in mice is a seventeen-day process that begins with the rise of six primordial germ cells on embryonic day five (E5) and ends with the formation of primordial follicles on postnatal day two (P2). We reviewed the current literature and created a visual representation of early ovarian development that depicts the important molecular events and associated phenotypic outcomes based on primary data. The visual representation shows the timeline of key signaling interactions and regulation of protein expression in different cells involved in ovarian development. The major developmental events were divided into five phases: 1) origin of germ cells and maintenance of pluripotency; 2) primordial germ cell migration; 3) sex differentiation; 4) formation of germ cell nests; and 5) germ cell nest breakdown and primordial follicle formation. This review and visual representation provide a summary of the current scientific understanding of the key regulation and signaling during ovarian development and highlights areas needing further study. The visual representation can be used as an educational resource to link molecular events with phenotypic outcomes; serves as a tool to generate new hypotheses and predictions of adverse reproductive outcomes due to perturbations at the molecular and cellular levels; and provides a comprehendible foundation for computational model development and hypothesis testing.

  12. Observations on germ band development in the cellar spider Pholcus phalangioides.

    PubMed

    Turetzek, Natascha; Prpic, Nikola-Michael

    2016-11-01

    Most recent studies of spider embryonic development have focused on representatives of the species-rich group of entelegyne spiders (over 80 % of all extant species). Embryogenesis in the smaller spider groups, however, is less well studied. Here, we describe the development of the germ band in the spider species Pholcus phalangioides, a representative of the haplogyne spiders that are phylogenetically the sister group of the entelegyne spiders. We show that the transition from radially symmetric embryonic anlage to the bilaterally symmetric germ band involves the accumulation of cells in the centre of the embryonic anlage (primary thickening). These cells then disperse all across the embryonic anlage. A secondary thickening of cells then appears in the centre of the embryonic anlage, and this thickening expands and forms the segment addition zone. We also confirm that the major part of the opisthosoma initially develops as a tube shaped structure, and its segments are then sequentially folded down on the yolk during inversion. This special mode of opisthosoma formation has not been reported for entelegyne spiders, but a more comprehensive sampling of this diverse group is necessary to decide whether this peculiarity is indeed lacking in the entelegyne spiders.

  13. Molecular and biological aspects of early germ cell development in interspecies hybrids between chickens and pheasants.

    PubMed

    Kang, Seok Jin; Sohn, Sea Hwan; Kang, Kyung Soo; Lee, Hyung Chul; Lee, Seul Ki; Choi, Jin Won; Han, Jae Yong

    2011-03-01

    Interspecific hybrids provide insights into fundamental genetic principles, and may prove useful for biotechnological applications and as tools for the conservation of endangered species. In the present study, interspecies hybrids were generated between the Korean ring-necked pheasant (Phasianus colchicus) and the White Leghorn chicken (Gallus gallus domesticus). We determined whether these hybrids were good recipients for the production of germline chimeric birds. PCR-based species-specific amplification and karyotype analyses showed that the hybrids inherited genetic material from both parents. Evaluation of biological function indicated that the growth rates of hybrids during the exponential phase (body weight/week) were similar to those of the pheasant but not the chicken, and that the incubation period for hatching was significantly different from that of both parents. Primordial germ cells (PGCs) of hybrids reacted with a pheasant PGC-specific antibody and circulated normally in blood vessels. The peak time of hybrid PGC migration was equivalent to that of the pheasant. In late embryonic stages, germ cells were detected by the QCR1 antibody on 15 d male gonads and were normally localized in the seminiferous cords. We examined the migration ability and developmental localization of exogenous PGCs transferred into the blood vessels of 63 h hybrid embryos. Donor-derived PGCs reacted with a donor-specific antibody were detected on 7 d gonads and the seminiferous tubules of hatchlings. Therefore, germ cell transfer into developing embryos of an interspecies hybrid can be efficiently used for the conservation of threatened animals and endangered species, and many biotechnological applications. Copyright © 2011 Elsevier Inc. All rights reserved.

  14. Tooth development in a scincid lizard, Chalcides viridanus (Squamata), with particular attention to enamel formation.

    PubMed

    Delgado, Sidney; Davit-Béal, Tiphaine; Allizard, Françoise; Sire, Jean-Yves

    2005-01-01

    Comparative analysis of tooth development in the main vertebrate lineages is needed to determine the various evolutionary routes leading to current dentition in living vertebrates. We have used light, scanning and transmission electron microscopy to study tooth morphology and the main stages of tooth development in the scincid lizard, Chalcides viridanus, viz., from late embryos to 6-year-old specimens of a laboratory-bred colony, and from early initiation stages to complete differentiation and attachment, including resorption and enamel formation. In C. viridanus, all teeth of a jaw have a similar morphology but tooth shape, size and orientation change during ontogeny, with a constant number of tooth positions. Tooth morphology changes from a simple smooth cone in the late embryo to the typical adult aspect of two cusps and several ridges via successive tooth replacement at every position. First-generation teeth are initiated by interaction between the oral epithelium and subjacent mesenchyme. The dental lamina of these teeth directly branches from the basal layer of the oral epithelium. On replacement-tooth initiation, the dental lamina spreads from the enamel organ of the previous tooth. The epithelial cell population, at the dental lamina extremity and near the bone support surface, proliferates and differentiates into the enamel organ, the inner (IDE) and outer dental epithelium being separated by stellate reticulum. IDE differentiates into ameloblasts, which produce enamel matrix components. In the region facing differentiating IDE, mesenchymal cells differentiate into dental papilla and give rise to odontoblasts, which first deposit a layer of predentin matrix. The first elements of the enamel matrix are then synthesised by ameloblasts. Matrix mineralisation starts in the upper region of the tooth (dentin then enamel). Enamel maturation begins once the enamel matrix layer is complete. Concomitantly, dental matrices are deposited towards the base of the

  15. Essential Role for NFI-C/CTF Transcription-Replication Factor in Tooth Root Development

    PubMed Central

    Steele-Perkins, George; Butz, Kenneth G.; Lyons, Gary E.; Zeichner-David, Margarita; Kim, Heung-Joong; Cho, Moon-Il; Gronostajski, Richard M.

    2003-01-01

    The mammalian tooth forms by a series of reciprocal epithelial-mesenchymal interactions. Although several signaling pathways and transcription factors have been implicated in regulating molar crown development, relatively little is known about the regulation of root development. Four genes encoding nuclear factor I (NFI) transcription-replication proteins are present in the mouse genome: Nfia, Nfib, Nfic, and Nfix. In order to elucidate its physiological role(s), we disrupted the Nfic gene in mice. Heterozygous animals appear normal, whereas Nfic−/− mice have unique tooth pathologies: molars lacking roots, thin and brittle mandibular incisors, and weakened abnormal maxillary incisors. Feeding in Nfic−/− mice is impaired, resulting in severe runting and premature death of mice reared on standard laboratory chow. However, a soft-dough diet mitigates the feeding impairment and maintains viability. Although Nfic is expressed in many organ systems, including the developing tooth, the tooth root development defects were the prominent phenotype. Indeed, molar crown development is normal, and well-nourished Nfic−/− animals are fertile and can live as long as their wild-type littermates. The Nfic mutation is the first mutation described that affects primarily tooth root formation and should greatly aid our understanding of postnatal tooth development. PMID:12529411

  16. Altered tooth morphogenesis after silencing the planar cell polarity core component, Vangl2.

    PubMed

    Wu, Zhaoming; Epasinghe, Don Jeevanie; He, Jinquan; Li, Liwen; Green, David W; Lee, Min-Jung; Jung, Han-Sung

    2016-12-01

    Vangl2, one of the core components of the planar cell polarity (PCP) pathway, has an important role in the regulation of morphogenesis in several tissues. Although the expression of Vangl2 has been detected in the developing tooth, its role in tooth morphogenesis is not known. In this study, we show that Vangl2 is expressed in the inner dental epithelium (IDE) and in the secondary enamel knots (SEKs) of bell stage tooth germs. Inhibition of Vangl2 expression by siRNA treatment in in vitro-cultured tooth germs resulted in retarded tooth germ growth with deregulated cell proliferation and apoptosis. After kidney transplantation of Vangl2 siRNA-treated tooth germs, teeth were observed to be small and malformed. We also show that Vangl2 is required to maintain the proper pattern of cell alignment in SEKs, which maybe important for the function of SEKs as signaling centers. These results suggest that Vangl2 plays an important role in the morphogenesis of teeth.

  17. Expression of Ki-67, Oct-4, γ-tubulin and α-tubulin in human tooth development.

    PubMed

    Kero, Darko; Novakovic, Josip; Vukojevic, Katarina; Petricevic, Josko; Kalibovic Govorko, Danijela; Biocina-Lukenda, Dolores; Saraga-Babic, Mirna

    2014-11-01

    To analyze factors controlling cell proliferation and differentiation, and appearance of primary cilia during the cap and bell stages of incisor or/and canine human enamel organs. Qualitative and quantitative analysis of proliferating Ki-67 positive cells and expression of γ-tubulin, α-tubulin and Oct-4 was immunohistochemically analyzed in the cap an bell stages of 10 developing human incisor and canine germs, 8-21 weeks old. During the analyzed period, ratio of Ki-67 positive cells changed in outer enamel epithelium from 48.86% to 24.52%, in inner enamel epithelium increased from 56.11% to 60.06% and then dropped to 44.24%. While in dental papilla proliferation first increased from 46.26% to 55.45%, and then dropped to 22.08%, a constant decrease of proliferation characterized enamel reticulum (from 46.26% to 15.49%). Strong cytoplasmic Oct-4 expression characterized epithelial parts of enamel organ, particularly the differentiating ameloblasts. During further development, Oct-4 expression shifted to both nuclear and cytoplasmic expression in mesenchymal tooth components. Primary cilia characterized most of the cells in developing enamel organ. While non-ciliated (proliferating) cells mainly contained two centrioles (γ-tubulin), the primary cilia (α-tubulin) were arising from basal bodies (γ-tubulin) of non-proliferating cells. We suggest that increase in cell proliferation enables growth of enamel organ, while its selective decrease leads to disintegration of some tooth parts. Drop of proliferation coincided with initiation of ameloblast and odontoblast differentiation. Additionally, cell differentiation was accompanied by increased expression of Oct-4 and probably by signalling via primary cilia, both regulating processes of cell proliferation and differentiation. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. The Sirt6 gene: Does it play a role in tooth development?

    PubMed Central

    Liao, Xueyang; Feng, Bo; Zhang, Demao; Liu, Peng; Zhou, Xuedong; Li, Ruimin; Ye, Ling

    2017-01-01

    Dental Mesenchymal Cells (DMCs) are known to play a role in tooth development as well as in the repair and regeneration of dental tissue. A large number of signaling molecules regulate the proliferation and differentiation of DMC, though the underlying mechanisms are still not fully understood. Sirtuin-6 (SIRT6), a key regulator of aging, can exert an impact on embryonic stem cell (ESC) differentiation. The experimental deletion of Sirt6 in mouse bone marrow cells has been found to have an inhibiting impact on the bone mineral density and the osteogenic differentiation of these cells. The possible role of Sirt6 in tooth development, however, has at present remained largely unexplored. In the present study, we found that SIRT6 had no effect on tooth development before birth. However, Sirt6 gene deletion in knockout mice did have two post-natal impacts: a delay in tooth eruption and sluggishness in the development of dental roots. We propose an explanation of the possible molecular basis of the changes observed in Sirt6-/- mice. SIRT6 is expressed in mouse odontoblasts. Sirt6 deletion enhanced the proliferation of DMCs, as well as their capacity for adipogenic differentiation. On the other hand, it inhibited their capacity for in vitro osteogenic/chondrogenic differentiation. Further studies suggested that other factors may mediate the role of Sirt6 in odontogenesis. These include the nuclear factor kappa B (NF-κB), p38 mitogen-activated protein kinase (p38-MAPK), extracellular regulated MAP kinase (ERK) pathways and the mitochondrial energy. We demonstrated that Sirt6 plays a role in tooth root formation and confirmed that SIRT6 is necessary for DMC differentiation as well as for the development of the tooth root and for eventual tooth eruption. These results establish a new link between SIRT6 and tooth development. PMID:28355287

  19. The Sirt6 gene: Does it play a role in tooth development?

    PubMed

    Liao, Xueyang; Feng, Bo; Zhang, Demao; Liu, Peng; Zhou, Xuedong; Li, Ruimin; Ye, Ling

    2017-01-01

    Dental Mesenchymal Cells (DMCs) are known to play a role in tooth development as well as in the repair and regeneration of dental tissue. A large number of signaling molecules regulate the proliferation and differentiation of DMC, though the underlying mechanisms are still not fully understood. Sirtuin-6 (SIRT6), a key regulator of aging, can exert an impact on embryonic stem cell (ESC) differentiation. The experimental deletion of Sirt6 in mouse bone marrow cells has been found to have an inhibiting impact on the bone mineral density and the osteogenic differentiation of these cells. The possible role of Sirt6 in tooth development, however, has at present remained largely unexplored. In the present study, we found that SIRT6 had no effect on tooth development before birth. However, Sirt6 gene deletion in knockout mice did have two post-natal impacts: a delay in tooth eruption and sluggishness in the development of dental roots. We propose an explanation of the possible molecular basis of the changes observed in Sirt6-/- mice. SIRT6 is expressed in mouse odontoblasts. Sirt6 deletion enhanced the proliferation of DMCs, as well as their capacity for adipogenic differentiation. On the other hand, it inhibited their capacity for in vitro osteogenic/chondrogenic differentiation. Further studies suggested that other factors may mediate the role of Sirt6 in odontogenesis. These include the nuclear factor kappa B (NF-κB), p38 mitogen-activated protein kinase (p38-MAPK), extracellular regulated MAP kinase (ERK) pathways and the mitochondrial energy. We demonstrated that Sirt6 plays a role in tooth root formation and confirmed that SIRT6 is necessary for DMC differentiation as well as for the development of the tooth root and for eventual tooth eruption. These results establish a new link between SIRT6 and tooth development.

  20. Temporal germ cell development strategy during spermatogenesis within the testis of the Ground Skink, Scincella lateralis (Sauria: Scincidae).

    PubMed

    Rheubert, J L; McHugh, H H; Collier, M H; Sever, D M; Gribbins, K M

    2009-07-01

    Ground Skink (Scincella lateralis) testes were examined histologically to determine the testicular organization and germ cell development strategy employed during spermatogenesis. Testicular tissues were collected from 19 ground skinks from Aiken County, South Carolina during the months of March-June, August, and October. The testes consisted of seminiferous tubules lined with germinal epithelia in which germ cells matured in close association with Sertoli cells. As germ cells matured, they migrated away from the basal lamina of the epithelia towards the lumina of the seminiferous tubules. The testes were spermatogenically active during the months of March, April, May, June, and October (largest seminiferous tubule diameters and epithelial heights), but entered a quiescent period in August (smallest seminiferous tubule diameter and epithelial height) where only spermatogonia type A and B and early spermatocytes were present in low numbers within the seminiferous epithelium. Although the testicular organization was similar to other amniotes, a temporal germ cell development strategy was employed during spermatogenesis within Ground Skinks, similar to that of anamniotes. Thus, this skink's germ cell development strategy, which also has been recently reported in all other major reptilian clades, may represent an evolutionary intermediate in terms of testicular organization between anamniotes and birds and mammals.

  1. On the role of germ cells in mammalian gonad development: quiet passengers or back-seat drivers?

    PubMed

    Rios-Rojas, Clarissa; Bowles, Josephine; Koopman, Peter

    2015-04-01

    In addition to their role as endocrine organs, the gonads nurture and protect germ cells, and regulate the formation of gametes competent to convey the genome to the following generation. After sex determination, gonadal somatic cells use several known signalling pathways to direct germ cell development. However, the extent to which germ cells communicate back to the soma, the molecular signals they use to do so and the significance of any such signalling remain as open questions. Herein, we review findings arising from the study of gonadal development and function in the absence of germ cells in a range of organisms. Most published studies support the view that germ cells are unimportant for foetal gonadal development in mammals, but later become critical for stabilisation of gonadal function and somatic cell phenotype. However, the lack of consistency in the data, and clear differences between mammals and other vertebrates and invertebrates, suggests that the story may not be so simple and would benefit from more careful analysis using contemporary molecular, cell biology and imaging tools. © 2015 Society for Reproduction and Fertility.

  2. PCPH expression is an early event in the development of testicular germ cell tumors.

    PubMed

    Regadera, Javier; Blánquez, María José; González-Peramato, Pilar; Nistal, Manuel; Miller, Jennifer C; Tirado, Oscar M; Notario, Vicente

    2006-03-01

    Testicular germ cell tumors (TGCTs) include various malignancies with distinct pathologies that share a common precursor lesion (intratubular germ cell neoplasia, unclassified, ITGCNU, or carcinoma in situ, CIS). TGCTs, as a whole, represent a highly curable tumor paradigm, with high sensitivity to radiotherapy and, especially, to cisplatin-based chemotherapy. However, a percentage of cases display therapeutic resistance, and the molecular mechanisms underlying such resistant phenotype remain to be elucidated. We put forward the notion that expression of oncogenic forms of the PCPH gene, which are known to confer resistance to radiation and chemotherapeutic drugs, including cisplatin, may be expressed in TGCTs, and thus contribute to the development of therapeutic resistance. To begin testing this concept, we studied PCPH expression in human TGCT cell lines and in 54 solid tumors by RT-PCR, western immunoblot and immunohistochemistry. The results demonstrated that: i) PCPH is expressed in TGCT cell lines and tumors, including CIS; ii) its expression levels vary among different TGCT pathologies, being generally higher in well differentiated regions and lower in areas of predominant proliferation; iii) PCPH expression is substantially increased in tumors relative to matched normal testicular tissue; iv) tumor samples express PCPH polypeptides of low molecular mass, consistent with the known size of the PCPH oncoprotein, that are either absent from, or markedly reduced in, matched normal tissue. Collectively, these results positively identify PCPH as a good early molecular marker for testicular neoplasms, and strongly indicate that immunodetection of truncated PCPH polypeptides may be a useful diagnostic tool for TGCT.

  3. Development of fertile mouse oocytes from mitotic germ cells in vitro.

    PubMed

    Morohaku, Kanako; Hirao, Yuji; Obata, Yayoi

    2017-09-01

    Mammalian fetal ovaries contain numerous primordial germ cells (PGCs), although few mature oocytes are obtained from females, owing to apoptosis and follicle atresia. The regulatory mechanisms underlying oogenesis/folliculogenesis remain unknown. Development of methods for obtaining mature oocytes from PGCs in fetal ovaries in vitro could contribute to clarifying these mechanisms. The failure of follicle assembly has been found to be the most challenging aspect in conventional culture conditions. Recently, we established novel culture conditions that enable successful follicle assembly, sustaining interactions between the oocyte and somatic cells, and, in turn, promoting oocyte growth and maturation. Mature oocytes were differentiated from PGCs after a 1-month culture period. A hundred mouse offspring were obtained from approximately a thousand mature oocytes, indicating that oocytes that were differentiated from PGCs in vitro acquired totipotency after fertilization. Here we provide a detailed protocol for using this in vitro system. This in vitro system will potentially provide a novel platform for studying oogenesis and preservation of female germ cells.

  4. Pharmacotherapeutic treatment of germ cell tumors: standard of care and recent developments.

    PubMed

    Oing, Christoph; Seidel, Christoph; von Amsberg, Gunhild; Oechsle, Karin; Bokemeyer, Carsten

    2016-01-01

    Testicular germ cell tumors are the most common malignancy among men aged 40 and less. Since the introduction of cisplatin-based combination chemotherapy, germ cell tumors are among the most curable solid tumors with cure rates of 95% in all patients and > 80% in metastatic disease. Current standards and future developments in GCT treatment, including adjuvant chemotherapy, first line treatment for metastatic disease, and salvage regimens in case of relapse and refractory disease. Maintaining therapeutic success while further reducing treatment-related toxicity is paramount. Cancer-specific survival in localized disease approximates 100%. Therefore, orchidectomy followed by active surveillance is the preferred approach for all seminomas and non-seminomas lacking lymphovascular invasion. Non-seminomas with lymphovascular invasion should be offered adjuvant treatment with one cycle of bleomycin, etoposide and cisplatin (BEP). The BEP regimen remains standard of care for metastatic disease, while the role of primary high-dose chemotherapy in case of inadequate tumor-marker decline or presence of high-risk features (i.e. mediastinal origin, non-pulmonary visceral metastases) remains to be elucidated. Several curative salvage chemotherapy combinations are available, i.e. TIP, VeIP, GIP or high-dose carboplatin and etoposide. GOP is the current option of choice in cisplatin-refractory patients. Novel targeted agents failed to improve treatment outcome so far.

  5. A simple rule governs the evolution and development of hominin tooth size.

    PubMed

    Evans, Alistair R; Daly, E Susanne; Catlett, Kierstin K; Paul, Kathleen S; King, Stephen J; Skinner, Matthew M; Nesse, Hans P; Hublin, Jean-Jacques; Townsend, Grant C; Schwartz, Gary T; Jernvall, Jukka

    2016-02-25

    The variation in molar tooth size in humans and our closest relatives (hominins) has strongly influenced our view of human evolution. The reduction in overall size and disproportionate decrease in third molar size have been noted for over a century, and have been attributed to reduced selection for large dentitions owing to changes in diet or the acquisition of cooking. The systematic pattern of size variation along the tooth row has been described as a 'morphogenetic gradient' in mammal, and more specifically hominin, teeth since Butler and Dahlberg. However, the underlying controls of tooth size have not been well understood, with hypotheses ranging from morphogenetic fields to the clone theory. In this study we address the following question: are there rules that govern how hominin tooth size evolves? Here we propose that the inhibitory cascade, an activator-inhibitor mechanism that affects relative tooth size in mammals, produces the default pattern of tooth sizes for all lower primary postcanine teeth (deciduous premolars and permanent molars) in hominins. This configuration is also equivalent to a morphogenetic gradient, finally pointing to a mechanism that can generate this gradient. The pattern of tooth size remains constant with absolute size in australopiths (including Ardipithecus, Australopithecus and Paranthropus). However, in species of Homo, including modern humans, there is a tight link between tooth proportions and absolute size such that a single developmental parameter can explain both the relative and absolute sizes of primary postcanine teeth. On the basis of the relationship of inhibitory cascade patterning with size, we can use the size at one tooth position to predict the sizes of the remaining four primary postcanine teeth in the row for hominins. Our study provides a development-based expectation to examine the evolution of the unique proportions of human teeth.

  6. Molecular characterization of dental development in a toothed archosaur, the American alligator Alligator mississippiensis.

    PubMed

    Weeks, Olivia; Bhullar, Bhart-Anjan S; Abzhanov, Arhat

    2013-01-01

    Few skeletal structures are as informative of the adaptive natural history of vertebrate animals as their teeth. Understanding principles of tooth development is key to understanding evolution of the vertebrate dentition in general and emergence of multiple specialized tooth types in particular. Morphological and phylogenetic considerations suggest that crocodilians have the most primitive mode of dentition within extant tetrapods, displaying simple, conical, socketed, and continuously replaced teeth. Previous histological studies revealed several dental fates, including functional and non-functional teeth (rudiments) in the developing alligator embryos. We analyze expression of key odontogenic regulators and markers to better characterize the molecular patterning of crocodilian dentition. Importantly, we demonstrate that the morphologically distinct tooth types in Alligator mississippiensis are distinguishable by differences in their developmental programs. We also present evidence showing that tooth maturation is accompanied by dynamic gene expression in the epithelial and mesenchymal cells involved in tooth development. Our data reveal a significant morphological and genetic variation in early dental fates. We believe that this underlying developmental variation reflects modularity, or the ability of teeth to develop semi-autonomously along the alligator jaw. We propose that such modularity may have been a crucial for adaptive evolution within Amniota, allowing for the progressive modifications to tooth replacement, number, and shape.

  7. Transcriptome analysis reveals differentially expressed genes associated with germ cell and gonad development in the Southern bluefin tuna (Thunnus maccoyii).

    PubMed

    Bar, Ido; Cummins, Scott; Elizur, Abigail

    2016-03-10

    Controlling and managing the breeding of bluefin tuna (Thunnus spp.) in captivity is an imperative step towards obtaining a sustainable supply of these fish in aquaculture production systems. Germ cell transplantation (GCT) is an innovative technology for the production of inter-species surrogates, by transplanting undifferentiated germ cells derived from a donor species into larvae of a host species. The transplanted surrogates will then grow and mature to produce donor-derived seed, thus providing a simpler alternative to maintaining large-bodied broodstock such as the bluefin tuna. Implementation of GCT for new species requires the development of molecular tools to follow the fate of the transplanted germ cells. These tools are based on key reproductive and germ cell-specific genes. RNA-Sequencing (RNA-Seq) provides a rapid, cost-effective method for high throughput gene identification in non-model species. This study utilized RNA-Seq to identify key genes expressed in the gonads of Southern bluefin tuna (Thunnus maccoyii, SBT) and their specific expression patterns in male and female gonad cells. Key genes involved in the reproductive molecular pathway and specifically, germ cell development in gonads, were identified using analysis of RNA-Seq transcriptomes of male and female SBT gonad cells. Expression profiles of transcripts from ovary and testis cells were compared, as well as testis germ cell-enriched fraction prepared with Percoll gradient, as used in GCT studies. Ovary cells demonstrated over-expression of genes related to stem cell maintenance, while in testis cells, transcripts encoding for reproduction-associated receptors, sex steroids and hormone synthesis and signaling genes were over-expressed. Within the testis cells, the Percoll-enriched fraction showed over-expression of genes that are related to post-meiosis germ cell populations. Gonad development and germ cell related genes were identified from SBT gonads and their expression patterns in

  8. Tooth-bone morphogenesis during postnatal stages of mouse first molar development.

    PubMed

    Lungová, Vlasta; Radlanski, Ralf J; Tucker, Abigail S; Renz, Herbert; Míšek, Ivan; Matalová, Eva

    2011-06-01

    The first mouse molar (M1) is the most common model for odontogenesis, with research particularly focused on prenatal development. However, the functional dentition forms postnatally, when the histogenesis and morphogenesis of the tooth is completed, the roots form and the tooth physically anchors into the jaw. In this work, M1 was studied from birth to eruption, assessing morphogenesis, proliferation and apoptosis, and correlating these with remodeling of the surrounding bony tissue. The M1 completed crown formation between postnatal (P) days 0-2, and the development of the tooth root was initiated at P4. From P2 until P12, cell proliferation in the dental epithelium reduced and shifted downward to the apical region of the forming root. In contrast, proliferation was maintained or increased in the mesenchymal cells of the dental follicle. At later stages, before tooth eruption (P20), cell proliferation suddenly ceased. This withdrawal from the cell cycle correlated with tooth mineralization and mesenchymal differentiation. Apoptosis was observed during all stages of M1 postnatal morphogenesis, playing a role in the removal of cells such as osteoblasts in the mandibular region and working together with osteoclasts to remodel the bone around the developing tooth. At more advanced developmental stages, apoptotic cells and bodies accumulated in the cell layers above the tooth cusps, in the path of eruption. Three-dimensional reconstruction of the developing postnatal tooth and bone indicates that the alveolar crypts form by resorption underneath the primordia, whereas the ridges form by active bone growth between the teeth and roots to form a functional complex.

  9. Tooth-bone morphogenesis during postnatal stages of mouse first molar development

    PubMed Central

    Lungová, Vlasta; Radlanski, Ralf J; Tucker, Abigail S; Renz, Herbert; Míšek, Ivan; Matalová, Eva

    2011-01-01

    The first mouse molar (M1) is the most common model for odontogenesis, with research particularly focused on prenatal development. However, the functional dentition forms postnatally, when the histogenesis and morphogenesis of the tooth is completed, the roots form and the tooth physically anchors into the jaw. In this work, M1 was studied from birth to eruption, assessing morphogenesis, proliferation and apoptosis, and correlating these with remodeling of the surrounding bony tissue. The M1 completed crown formation between postnatal (P) days 0–2, and the development of the tooth root was initiated at P4. From P2 until P12, cell proliferation in the dental epithelium reduced and shifted downward to the apical region of the forming root. In contrast, proliferation was maintained or increased in the mesenchymal cells of the dental follicle. At later stages, before tooth eruption (P20), cell proliferation suddenly ceased. This withdrawal from the cell cycle correlated with tooth mineralization and mesenchymal differentiation. Apoptosis was observed during all stages of M1 postnatal morphogenesis, playing a role in the removal of cells such as osteoblasts in the mandibular region and working together with osteoclasts to remodel the bone around the developing tooth. At more advanced developmental stages, apoptotic cells and bodies accumulated in the cell layers above the tooth cusps, in the path of eruption. Three-dimensional reconstruction of the developing postnatal tooth and bone indicates that the alveolar crypts form by resorption underneath the primordia, whereas the ridges form by active bone growth between the teeth and roots to form a functional complex. PMID:21418206

  10. Complex patterns of tooth replacement revealed in the fruit bat (Eidolon helvum).

    PubMed

    Popa, Elena M; Anthwal, Neal; Tucker, Abigail S

    2016-12-01

    How teeth are replaced during normal growth and development has long been an important question for comparative and developmental anatomy. Non-standard model animals have become increasingly popular in this field due to the fact that the canonical model laboratory mammal, the mouse, develops only one generation of teeth (monophyodonty), whereas the majority of mammals possess two generations of teeth (diphyodonty). Here we used the straw-coloured fruit bat (Eidolon helvum), an Old World megabat, which has two generations of teeth, in order to observe the development and replacement of tooth germs from initiation up to mineralization stages. Our morphological study uses 3D reconstruction of histological sections to uncover differing arrangements of the first and second-generation tooth germs during the process of tooth replacement. We show that both tooth germ generations develop as part of the dental lamina, with the first generation detaching from the lamina, leaving the free edge to give rise to a second generation. This separation was particularly marked at the third premolar locus, where the primary and replacement teeth become positioned side by side, unconnected by a lamina. The position of the replacement tooth, with respect to the primary tooth, varied within the mouth, with replacements forming posterior to or directly lingual to the primary tooth. Development of replacement teeth was arrested at some tooth positions and this appeared to be linked to the timing of tooth initiation and the subsequent rate of development. This study adds an additional species to the growing body of non-model species used in the study of tooth replacement, and offers a new insight into the development of the diphyodont condition. © 2016 Anatomical Society.

  11. Spatiotemporal expression of NGFR during pre-natal human tooth development.

    PubMed

    Becktor, K B; Hansen, B F; Nolting, D; Kjaer, I

    2002-05-01

    The relation between nerve growth factor receptor (NGFR) in the human pre-natal tooth buds and the dental follicle was investigated. In particular, we sought to determine if there is a specific pattern of p75NGFR expression in developing human tooth buds and their surrounding tissue. The Department of Orthodontics at Copenhagen University, Denmark. Histological sections from 11 fetuses, aged 11-21 gestational weeks. The sections were studied by conventional immunohistochemistry. Specific spatiotemporal patterns of p75NGFR reactions were observed in the tooth buds and dental follicle: Before matrix production by the ameloblasts, the entire inner enamel epithelium and the entire dental follicle display p75NGFR immunoreactivity; after matrix production is initiated, the immunoreactivity of the matrix producing cells is lost, as is that of the dental follicle adjacent to these matrix-producing cells. A unique spatiotemporal distribution of NGFR in the pre-eruptive human tooth bud was demonstrated.

  12. Differences between appressoria formed by germ tubes and appressorium-like structures developed by hyphal tips in Magnaporthe oryzae.

    PubMed

    Kong, Ling-An; Li, Guo-Tian; Liu, Yun; Liu, Mei-Gang; Zhang, Shi-Jie; Yang, Jun; Zhou, Xiao-Ying; Peng, You-Liang; Xu, Jin-Rong

    2013-07-01

    Melanized appressoria are highly specialized infection structures formed by germ tubes of the rice blast fungus Magnaporthe oryzae for plant infection. M. oryzae also forms appressorium-like structures on hyphal tips. Whereas appressorium formation by conidial germ tubes has been well characterized, formation of appressorium-like structures by hyphal tips is under-investigated. In a previous study, we found that the chs7 deletion mutant failed to form appressoria on germ tubes but were normal in the development of appressorium-like structures on artificial hydrophobic surfaces. In this study, we compared the differences between the formation of appressoria by germ tubes and appressorium-like structures by hyphal tips in M. oryzae. Structurally, both appressoria and appressorium-like structures had a melanin layer that was absent in the pore region. In general, the latters were 1.4-fold larger in size but had lower turgor pressure than appressoria, which is consistent with its lower efficiency in plant penetration. Treatments with cAMP, IBMX, or a cutin monomer efficiently induced appressorium formation but not the development of appressorium-like structures. In contrast, coating surfaces with waxes stimulated the formation of both infection structures. Studies with various signaling mutants indicate that Osm1 and Mps1 are dispensable but Pmk1 is essential for both appressorium formation and development of appressorium-like structures on hyphal tips. Interestingly, the cpkA mutant was reduced in the differentiation of appressorium-like structures but not appressorium formation. We also observed that the con7 mutant generated in our lab failed to form appressorium-like structures on hyphal tips but still produced appressoria by germ tubes on hydrophobic surfaces. Con7 is a transcription factor regulating the expression of CHS7. Overall, these results indicate that the development of appressorium-like structures by hyphal tips and formation of appressoria by germ

  13. Characterization of glycosaminoglycans during tooth development and mineralization in the axolotl, Ambystoma mexicanum.

    PubMed

    Wistuba, J; Völker, W; Ehmcke, J; Clemen, G

    2003-10-01

    Glycosaminoglycans (GAGs) involved in the formation of the teeth of Ambystoma mexicanum were located and characterized with the cuprolinic blue (CB) staining method and transmission electron microscopy (TEM). Glycosaminoglycan-cuprolinic blue precipitates (GAGCB) were found in different compartments of the mineralizing tissue. Various populations of elongated GAGCB could be discriminated both according to their size and their preferential distribution in the extracellular matrix (ECM). GAGCB populations that differ in their composition could be attributed not only to the compartments of the ECM but also to different zones and to different tooth types (early-larval and transformed). Larger precipitates were only observed within the dentine matrix of the shaft of the early-larval tooth. The composition of the populations differed significantly between the regions of the transformed tooth: pedicel, shaft and dividing zone. In later stages of tooth formation, small-sized GAGCBs were seen as intracellular deposits in the ameloblasts. It is concluded that the composition of GAGCB populations seems to play a role in the mineralization processes during tooth development in A. mexicanum and influence qualitative characteristics of the mineral in different tooth types and zones, and it is suggested that GAGs might be resorbed by the enamel epithelium during the late phase of enamel formation.

  14. Wnt/beta-catenin signaling plays an essential role in activation of odontogenic mesenchyme during early tooth development.

    PubMed

    Chen, Jianquan; Lan, Yu; Baek, Jin-A; Gao, Yang; Jiang, Rulang

    2009-10-01

    Classical tissue recombination studies demonstrated that initiation of tooth development depends on activation of odontogenic potential in the mesenchyme by signals from the presumptive dental epithelium. Although several members of the Wnt family of signaling molecules are expressed in the presumptive dental epithelium at the beginning of tooth initiation, whether Wnt signaling is directly involved in the activation of the odontogenic mesenchyme has not been characterized. In this report, we show that tissue-specific inactivation of beta-catenin, a central component of the canonical Wnt signaling pathway, in the developing tooth mesenchyme caused tooth developmental arrest at the bud stage in mice. We show that mesenchymal beta-catenin function is required for expression of Lef1 and Fgf3 in the developing tooth mesenchyme and for induction of primary enamel knot in the developing tooth epithelium. Expression of Msx1 and Pax9, two essential tooth mesenchyme transcription factors downstream of Bmp and Fgf signaling, respectively, were not altered in the absence of beta-catenin in the tooth mesenchyme. Moreover, we found that constitutive stabilization of beta-catenin in the developing palatal mesenchyme induced aberrant palatal epithelial invaginations that resembled early tooth buds both morphologically and in epithelial molecular marker expression, but without activating expression of Msx1 and Pax9 in the mesenchyme. Together, these results indicate that activation of the mesenchymal odontogenic program during early tooth development requires concerted actions of Bmp, Fgf and Wnt signaling from the presumptive dental epithelium to the mesenchyme.

  15. Exploring embryonic germ line development in the water flea, Daphnia magna, by zinc-finger-containing VASA as a marker.

    PubMed

    Sagawa, Kazunori; Yamagata, Hideo; Shiga, Yasuhiro

    2005-06-01

    VASA is an ATP-dependent RNA helicase belonging to the DEAD-box family that, in many organisms, is specifically expressed in germ line cells throughout the life cycle, making it a powerful molecular marker to study germ line development. To obtain further information on germ line development in crustaceans, we cloned VASA cDNAs from three branchiopod species: water fleas Daphnia magna and Moina macrocopa, and brine shrimp Artemia franciscana. RNA helicase domains in branchiopod VASA were highly conserved among arthropod classes. However, N-terminal RNA-binding domains in branchiopod VASA were highly diverged and, unlike other arthropod VASA reported so far, possessed repeats of retroviral-type zinc finger (CCHC) motifs. Raising specific antibodies against Daphnia VASA revealed that the primordial germ cells (PGCs) in this organism segregate at a very early cleavage stage of embryogenesis in parthenogenetic and sexual eggs. Clusters of PGCs then start to migrate inside the embryo and finally settle at both sides of the intestine, the site of future gonad development. RNA analyses suggested that maternally supplied vasa mRNA was responsible for early VASA expression, while zygotic expression started during blastodermal stage of development.

  16. Wnt5a regulates growth, patterning, and odontoblast differentiation of developing mouse tooth

    PubMed Central

    Lin, Minkui; Li, Lu; Liu, Chao; Liu, Hongbing; He, Fenglei; Yan, Fuhua; Zhang, Yanding; Chen, YiPing

    2011-01-01

    Wnt/β-catenin signaling is essential for tooth development beyond the bud stage, but little is known about the role of non-canonical Wnt signaling in odontogenesis. Here we compared the expression of Wnt5a, a representative of noncanonical Wnts, with that of Ror2, the Wnt5a receptor for non-canonical signaling, in the developing tooth, and analyzed tooth phenotype in Wnt5a mutants. Wnt5a deficient mice exhibit retarded tooth development beginning from E16.5, leading to the formation of smaller and abnormally patterned teeth with a delayed odontoblast differentiation at birth. These defects are associated with upregulated Axin2 and Shh expression in the dental epithelium and reduced levels of cell proliferation in the dental epithelium and mesenchyme. Retarded tooth development and defective odontoblast differentiation were also observed in Ror2 mutant mice. Our results suggest that Wnt5a regulates growth, patterning, and odontoblast differentiation during odontogenesis, at least partially by modulating Wnt/β-catenin canonical signaling. PMID:21246660

  17. Dental Age Estimation (DAE): Data management for tooth development stages including the third molar. Appropriate censoring of Stage H, the final stage of tooth development.

    PubMed

    Roberts, Graham J; McDonald, Fraser; Andiappan, Manoharan; Lucas, Victoria S

    2015-11-01

    The final stage of dental development of third molars is usually helpful to indicate whether or not a subject is aged over 18 years. A complexity is that the final stage of development is unlimited in its upper border. Investigators usually select an inappropriate upper age limit or censor point for this tooth development stage. The literature was searched for appropriate data sets for dental age estimation and those that provided the count (n), the mean (x¯), and the standard deviation (sd) for each of the tooth development stages. The Demirjian G and Demirjian H were used for this study. Upper and lower limits of the Stage G and Stage H data were calculated limiting the data to plus or minus three standard deviations from the mean. The upper border of Stage H was limited by appropriate censoring at the maximum value for Stage G. The maximum age at attainment from published data, for Stage H, ranged from 22.60 years to 34.50 years. These data were explored to demonstrate how censoring provides an estimate for the correct maximum age for the final stage of Stage H as 21.64 years for UK Caucasians. This study shows that confining the data array of individual tooth developments stages to ± 3sd provides a reliable and logical way of censoring the data for tooth development stages with a Normal distribution of data. For Stage H this is inappropriate as it is unbounded in its upper limit. The use of a censored data array for Stage H using Percentile values is appropriate. This increases the reliability of using third molar Stage H alone to determine whether or not an individual is over 18 years old. For Stage H, individual ancestral groups should be censored using the same technique. Copyright © 2015 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.

  18. Functional cues in the development of osseous tooth support in the pig, Sus scrofa.

    PubMed

    Popowics, T; Yeh, K; Rafferty, K; Herring, S

    2009-08-25

    Alveolar bone supports teeth during chewing through a ligamentous interface with tooth roots. Although tooth loads are presumed to direct the development and adaptation of these tissues, strain distribution in the alveolar bone at different stages of tooth eruption and periodontal development is unknown. This study investigates the biomechanical effects of tooth loading on developing alveolar bone as a tooth erupts into occlusion. Mandibular segments from miniature pigs, Sus scrofa, containing M(1) either erupting or in functional occlusion, were loaded in compression. Simultaneous recordings were made from rosette strain gages affixed to the lingual alveolar bone and the M(2) crypt. Overall, specimens with erupting M(1)s were more deformable than specimens with occluding M(1)s (mean stiffness of 246 vs. 944 MPa, respectively, p=0.004). The major difference in alveolar strain between the two stages was in orientation. The vertically applied compressive loads were more directly reflected in the alveolar bone strains of erupting M(1)s, than those of occluding M(1)s, presumably because of the mediation of a more mature periodontal ligament (PDL) in the latter. The PDL interface between occluding teeth and alveolar bone is likely to stiffen the system, allowing transmission of occlusal loads. Alveolar strains may provide a stimulus for bone growth in the alveolar process and crest.

  19. Germ cell cancer presenting as gastrointestinal bleeding and developing brain metastases: case report and review of the literature.

    PubMed

    Fu, Shuang; Avezbakiyev, Boris; Zhi, Wanqing; Kodali, Sreenath; Rizvon, Kaleem; Alaverdian, Artur; Freedman, Lester; Mejia, Jose; Shahzad, Ghulamullah; Gotlieb, Vladimir

    2012-11-01

    This paper describes a rare case of germ cell cancer with duodenum, brain and lung metastases. The patient presented with melena and left testicle enlargement. Orchiectomy revealed mixed germ cell cancer, enteroscopy revealed duodenal choriocarcinoma, and chest x-ray and computed tomography (CT) showed bilateral lung metastases. The patient received and tolerated cisplatinum-based chemotherapy, and responded well. However, he developed seizures 3 months later. MRI showed brain metastases and he was treated with whole-brain radiation. One month later, he developed progressive dyspnea. Chest CT showed worsening lung metastases. He received second-line chemotherapy, but died due to multiorgan failure. Germ cell cancer with nonpulmonary metastases has poor prognosis and the management of these patients requires a multimodal approach. Head CT should be considered as routine screening for all germ cell cancer patients on initial diagnosis and brain MRI should be considered for high-risk patients (with an embryo- or choriocarcinoma histology, dramatically elevated β-human chorionic gonadotropin and lung involvement).

  20. Fate of developing tooth buds located in relation to mandibular fractures in three infancy cases.

    PubMed

    Yamamoto, Kazuhiko; Matsusue, Yumiko; Murakami, Kazuhiro; Horita, Satoshi; Matsubara, Yuri; Kuraki, Miho; Kurihara, Miyako; Imai, Yuichiro; Sugiura, Tsutomu; Kirita, Tadaaki

    2010-08-01

    The fate of developing tooth buds located in relation to mandibular fractures was investigated in three infancy cases. Three infants, 2 girls and a boy, aged from 1 year and 5-months old to 2 years and 6-months old, were treated for dislocated mandibular fracture in the symphyseal region by manual reduction and fixation with a thermoforming splint and circumferential wiring under general anesthesia. Fracture healing was uneventful in all cases. A few years later, no obvious deformity of the jaw or malocclusion was observed; however, malformation of the crown was found in one of the permanent teeth on the fracture line in the first case. In the second case, no abnormality was observed in one of the permanent teeth on the fracture line, but the effect on the other tooth could not be evaluated due to abnormality of the tooth probably not related to the injury. In the third case, root formation was arrested in one of the permanent teeth on the fracture line and the tooth was lost early after eruption. The development of tooth buds on the fracture line is not predictable and therefore, should be monitored by regular follow up.

  1. A model of growth restraints to explain the development and evolution of tooth shapes in mammals.

    PubMed

    Osborn, Jeffrey W

    2008-12-07

    The problem investigated here is control of the development of tooth shape. Cells at the growing soft tissue interface between the ectoderm and mesoderm in a tooth anlage are observed to buckle and fold into a template for the shape of the tooth crown. The final shape is created by enamel secreted onto the folds. The pattern in which the folds develop is generally explained as a response to the pattern in which genes are locally expressed at the interface. This congruence leaves the problem of control unanswered because it does not explain how either pattern is controlled. Obviously, cells are subject to Newton's laws of motion so that mechanical forces and constraints must ultimately cause the movements of cells during tooth morphogenesis. A computer model is used to test the hypothesis that directional resistances to growth of the epithelial part of the interface could account for the shape into which the interface folds. The model starts with a single epithelial cell whose growth is constrained by 4 constant directional resistances (anterior, posterior, medial and lateral). The constraints force the growing epithelium to buckle and fold. By entering into the model different values for these constraints the modeled epithelium is induced to buckle and fold into the different shapes associated with the evolution of a human upper molar from that of a reptilian ancestor. The patterns and sizes of cusps and the sequences in which they develop are all correctly reproduced. The model predicts the changes in the 4 directional constraints necessary to develop and evolve from one tooth shape into another. I conclude more generally expressed genes that control directional resistances to growth, not locally expressed genes, may provide the information for the shape into which a tooth develops.

  2. Fertility facts: male and female germ cell development requires translational control by CPEB.

    PubMed

    Gebauer, F; Hentze, M W

    2001-08-01

    In the August issue of Developmental Cell, Tay and Richter examine the consequences of eliminating CPEB function in mice. Their studies reveal an important role for this translational regulator at the pachytene stage of germ cell differentiation.

  3. Development of space-fertilized eggs and formation of primordial germ cells in the embryos of medaka fish

    NASA Astrophysics Data System (ADS)

    Ijiri, K.

    In the second International Microgravity Laboratory (IML-2) mission in 1994, four small Japanese killifish (Medaka, Oryzias latipes) made a space travel of 15 days aboard a space shuttle. These four adult Medaka fish successfully mated in space for the first time among vertebrate animals. Moreover, the eggs they laid developed normally, at least in their external appearance, hatching as fry (baby fish) in space. Fish mated and laid eggs every day during the first week. Near the end of the mission most of the eggs had a well-developed body with two pigmented eyes. In total, 43 eggs were laid (detected), out of which 8 fry hatched in space, as truly `space-originated' babies. A further 30 fry hatched within 3 days after landing. This is the normal hatching rate, compared with the ground-based data. Among the 8 space-originated fry, four were killed for histological sections, and germ cells at the gonadal region were counted for each fry. Their numbers were in the range of the germ cells of the normal control fry (ground-kept samples). Thus, as embryos developed normally in their external appearance, inside the embryos the formation of primordial germ cells took place normally in space, and their migration to the genital ridges was not hindered by microgravity. The two of the remaining space-originated fry have grown up and been creating their offspring in the laboratory. This proved that the primordial germ cells formed in space were also normal from a functional point of view. The four space-travelled adult fish re-started mating and laying eggs on the 7th day after landing and continued to do so every day afterward. Fertilization rate and hatchability of these eggs were as high as the eggs laid by the laboratory-kept fish. This fact implies that in gametogenesis of adult fish, there are no specific stages of germ cells extremely susceptible to microgravity.

  4. Analgesic exposure in pregnant rats affects fetal germ cell development with inter-generational reproductive consequences

    PubMed Central

    Dean, Afshan; van den Driesche, Sander; Wang, Yili; McKinnell, Chris; Macpherson, Sheila; Eddie, Sharon L.; Kinnell, Hazel; Hurtado-Gonzalez, Pablo; Chambers, Tom J.; Stevenson, Kerrie; Wolfinger, Elke; Hrabalkova, Lenka; Calarrao, Ana; Bayne, Rosey AL; Hagen, Casper P.; Mitchell, Rod T.; Anderson, Richard A.; Sharpe, Richard M.

    2016-01-01

    Analgesics which affect prostaglandin (PG) pathways are used by most pregnant women. As germ cells (GC) undergo developmental and epigenetic changes in fetal life and are PG targets, we investigated if exposure of pregnant rats to analgesics (indomethacin or acetaminophen) affected GC development and reproductive function in resulting offspring (F1) or in the F2 generation. Exposure to either analgesic reduced F1 fetal GC number in both sexes and altered the tempo of fetal GC development sex-dependently, with delayed meiotic entry in oogonia but accelerated GC differentiation in males. These effects persisted in adult F1 females as reduced ovarian and litter size, whereas F1 males recovered normal GC numbers and fertility by adulthood. F2 offspring deriving from an analgesic-exposed F1 parent also exhibited sex-specific changes. F2 males exhibited normal reproductive development whereas F2 females had smaller ovaries and reduced follicle numbers during puberty/adulthood; as similar changes were found for F2 offspring of analgesic-exposed F1 fathers or mothers, we interpret this as potentially indicating an analgesic-induced change to GC in F1. Assuming our results are translatable to humans, they raise concerns that analgesic use in pregnancy could potentially affect fertility of resulting daughters and grand-daughters. PMID:26813099

  5. Peripheral developing odontoma in newborn. Report of two cases and literature review.

    PubMed

    Silva, Alan-Roger S; Carlos-Bregni, Roman; Vargas, Pablo-Agustin; de Almeida, Oslei-Paes; Lopes, Marcio-Ajudarte

    2009-11-01

    Extra-osseous odontogenic tumors are rarely observed. However, it is widely accepted that the remains of odontogenic epithelium entrapped in the oral soft tissues may be a possible source for peripheral odontogenic tumors differentiation. Peripheral developing odontoma is considered exceptionally rare, since few similar cases are described in the English-related literature under diverse nomenclature, such as irregular eruption, ectopic tooth, ectopic soft-tissue mesiodens, ectopic odontoma and extra-osseous tooth germ. Previously reported cases invariably affected children and surgical exploration revealed tooth germs exclusively embedded in the soft tissue without bone involvement. Microscopically, all these cases exhibited developing tooth germs composed of ameloblasts, enamel matrix, odontoblastic layer, dentin and dental papilla and the morphological findings seem to depend on the developmental stage of each tooth germ at discovery. Thus, we believe that it is relevant to report two additional cases that were recently diagnosed in Brazil and Guatemala, focusing on their nomenclature, correct diagnosis and further treatment.

  6. Roles of Bmp4 during tooth morphogenesis and sequential tooth formation

    PubMed Central

    Jia, Shihai; Zhou, Jing; Gao, Yang; Baek, Jin-A; Martin, James F.; Lan, Yu; Jiang, Rulang

    2013-01-01

    Previous studies have suggested that Bmp4 is a key Msx1-dependent mesenchymal odontogenic signal for driving tooth morphogenesis through the bud-to-cap transition. Whereas all tooth germs were arrested at the bud stage in Msx1–/– mice, we show that depleting functional Bmp4 mRNAs in the tooth mesenchyme, through neural crest-specific gene inactivation in Bmp4f/f;Wnt1Cre mice, caused mandibular molar developmental arrest at the bud stage but allowed maxillary molars and incisors to develop to mineralized teeth. We found that expression of Osr2, which encodes a zinc finger protein that antagonizes Msx1-mediated activation of odontogenic mesenchyme, was significantly upregulated in the molar tooth mesenchyme in Bmp4f/f;Wnt1Cre embryos. Msx1 heterozygosity enhanced maxillary molar developmental defects whereas Osr2 heterozygosity partially rescued mandibular first molar morphogenesis in Bmp4f/f;Wnt1Cre mice. Moreover, in contrast to complete lack of supernumerary tooth initiation in Msx1–/–Osr2–/– mice, Osr2–/–Bmp4f/f;Wnt1Cre compound mutant mice exhibited formation and subsequent arrest of supernumerary tooth germs that correlated with downregulation of Msx1 expression in the tooth mesenchyme. In addition, we found that the Wnt inhibitors Dkk2 and Wif1 were much more abundantly expressed in the mandibular than maxillary molar mesenchyme in wild-type embryos and that Dkk2 expression was significantly upregulated in the molar mesenchyme in Bmp4f/f;Wnt1Cre embryos, which correlated with the dramatic differences in maxillary and mandibular molar phenotypes in Bmp4f/f;Wnt1Cre mice. Together, these data indicate that Bmp4 signaling suppresses tooth developmental inhibitors in the tooth mesenchyme, including Dkk2 and Osr2, and synergizes with Msx1 to activate mesenchymal odontogenic potential for tooth morphogenesis and sequential tooth formation. PMID:23250216

  7. Hippo pathway/Yap regulates primary enamel knot and dental cusp patterning in tooth morphogenesis.

    PubMed

    Kwon, Hyuk-Jae Edward; Li, Liwen; Jung, Han-Sung

    2015-11-01

    The shape of an individual tooth crown is primarily determined by the number and arrangement of its cusps, i.e., cusp patterning. Enamel knots that appear in the enamel organ during tooth morphogenesis have been suggested to play important roles in cusp patterning. Animal model studies have shown that the Hippo pathway effector Yap has a critical function in tooth morphogenesis. However, the role of the Hippo pathway/Yap in cusp patterning has not been well documented and its specific roles in tooth morphogenesis remain unclear. Here, we provide evidence that Yap is a key mediator in tooth cusp patterning. We demonstrate a correlation between Yap localization and cell proliferation in developing tooth germs. We also show that, between the cap stage and bell stage, Yap is crucial for the suppression of the primary enamel knot and for the patterning of secondary enamel knots, which are the future cusp regions. When Yap expression is stage-specifically knocked down during the cap stage, the activity of the primary enamel knot persists into the bell-stage tooth germ, leading to ectopic cusp formation. Our data reveal the importance of the Hippo pathway/Yap in enamel knots and in the proper patterning of tooth cusps.

  8. Spatial and temporal expression of KLF4 and KLF5 during murine tooth development.

    PubMed

    Chen, Zhuo; Couble, Marie-Lise; Mouterfi, Nassima; Magloire, Henry; Chen, Zhi; Bleicher, Françoise

    2009-05-01

    KLF4 and KLF5, members of the Krüppel-like factor (KLF) family, play key roles in proliferation, differentiation and apoptosis during development. In order to determine if these transcription factors are associated with tooth development, we examined the expression pattern of KLF4 and KLF5 during murine tooth development. In situ hybridization and immunohistochemistry were performed to detect the expression pattern of KLF4 and KLF5 from E12.5 to PN3 during murine tooth development. In situ hybridization analysis revealed that Klf4 was specifically expressed in polarizing odontoblasts from E16.5 (incisor) or E18.5 (first molar) to PN3. Immunohistochemistry staining showed that KLF4 was specifically expressed in both polarizing odontoblasts and ameloblasts at the same stages. KLF5 was mainly expressed from E18.5 to PN3 in secretory ameloblasts when enamel mineralization occurs and in secretory odontoblasts. However, an expression of KLF5 was also observed at earlier stages (E14.5 and E16.5) mainly in proliferating epithelial cells. These results suggest that the expression of KLF4 is closely correlated to the growth-arrest and the first step of odontoblast and ameloblast differentiation. Furthermore, KLF5 maybe involved in proliferation at the early stages of tooth development and related to mineralization of both enamel and dentin matrices at later stages.

  9. The dynamics of supernumerary tooth development are differentially regulated by Sprouty genes.

    PubMed

    Lagronova-Churava, Svatava; Spoutil, Frantisek; Vojtechova, Simona; Lesot, Herve; Peterka, Miroslav; Klein, Ophir D; Peterkova, Renata

    2013-07-01

    In mice, a toothless diastema separates the single incisor from the three molars in each dental quadrant. In the prospective diastema of the embryo, small rudimentary buds are found that are presumed to be rudiments of suppressed teeth. A supernumerary tooth occurs in the diastema of adult mice carrying mutations in either Spry2 or Spry4. In the case of Spry2 mutants, the origin of the supernumerary tooth involves the revitalization of a rudimentary tooth bud (called R2), whereas its origin in the Spry4 mutants is not known. In addition to R2, another rudimentary primordium (called MS) arises more anteriorly in the prospective diastema. We investigated the participation of both rudiments (MS and R2) in supernumerary tooth development in Spry2 and Spry4 mutants by comparing morphogenesis, proliferation, apoptosis, size and Shh expression in the dental epithelium of MS and R2 rudiments. Increased proliferation and decreased apoptosis were found in MS and R2 at embryonic day (ED) 12.5 and 13.5 in Spry2(-/-) embryos. Apoptosis was also decreased in both rudiments in Spry4(-/-) embryos, but the proliferation was lower (similar to WT mice), and supernumerary tooth development was accelerated, exhibiting a cap stage by ED13.5. Compared to Spry2(-/-) mice, a high number of Spry4(-/-) supernumerary tooth primordia degenerated after ED13.5, resulting in a low percentage of supernumerary teeth in adults. We propose that Sprouty genes were implicated during evolution in reduction of the cheek teeth in Muridae, and their deletion can reveal ancestral stages of murine dental evolution. Copyright © 2013 Wiley Periodicals, Inc.

  10. The effect of fluoride on the developing tooth.

    PubMed

    Robinson, C; Connell, S; Kirkham, J; Brookes, S J; Shore, R C; Smith, A M

    2004-01-01

    This review aims to outline the effects of fluoride on the biological processes involved in the formation of tooth tissues, particularly dental enamel. Attention has been focused on mechanisms which, if compromised, could give rise to dental fluorosis. The literature is extensive and often confusing but a much clearer picture is emerging based on recent more detailed knowledge of odontogenesis. Opacity, characteristic of fluorotic enamel, results from incomplete apatite crystal growth. How this occurs is suggested by other changes brought about by fluoride. Matrix proteins, associated with the mineral phase, normally degraded and removed to permit final crystal growth, are to some extent retained in fluorotic tissue. Fluoride and magnesium concentrations increase while carbonate is reduced. Crystal surface morphology at the nano-scale is altered and functional ameloblast morphology at the maturation stage also changes. Fluoride incorporation into enamel apatite produces more stable crystals. Local supersaturation levels with regard to the fluoridated mineral will also be elevated facilitating crystal growth. Such changes in crystal chemistry and morphology, involving stronger ionic and hydrogen bonds, also lead to greater binding of modulating matrix proteins and proteolytic enzymes. This results in reduced degradation and enhanced retention of protein components in mature tissue. This is most likely responsible for porous fluorotic tissue, since matrix protein removal is necessary for unimpaired crystal growth. To resolve the outstanding problems of the role of cell changes and the precise reasons for protein retention more detailed studies will be required of alterations to cell function, effect on specific protein species and the nano-chemistry of the apatite crystal surfaces.

  11. Glucose uptake mediated by glucose transporter 1 is essential for early tooth morphogenesis and size determination of murine molars.

    PubMed

    Ida-Yonemochi, Hiroko; Nakatomi, Mitsushiro; Harada, Hidemitsu; Takata, Hiroki; Baba, Otto; Ohshima, Hayato

    2012-03-01

    Glucose is an essential source of energy for body metabolism and is transported into cells by glucose transporters (GLUTs). Well-characterized class I GLUT is subdivided into GLUTs1-4, which are selectively expressed depending on tissue glucose requirements. However, there is no available data on the role of GLUTs during tooth development. This study aims to clarify the functional significance of class I GLUT during murine tooth development using immunohistochemistry and an in vitro organ culture experiment with an inhibitor of GLUTs1/2, phloretin, and Glut1 and Glut2 short interfering RNA (siRNA). An intense GLUT1-immunoreaction was localized in the enamel organ of bud-stage molar tooth germs, where the active cell proliferation occurred. By the bell stage, the expression of GLUT1 in the dental epithelium was dramatically decreased in intensity, and subsequently began to appear in the stratum intermedium at the late bell stage. On the other hand, GLUT2-immunoreactivity was weakly observed in the whole tooth germs throughout all stages. The inhibition of GLUTs1/2 by phloretin in the bud-stage tooth germs induced the disturbance of primary enamel knot formation, resulting in the developmental arrest of the explants and the squamous metaplasia of dental epithelial cells. Furthermore, the inhibition of GLUTs1/2 in cap-to-bell-stage tooth germs reduced tooth size in a dose dependent manner. These findings suggest that the expression of GLUT1 and GLUT2 in the dental epithelial and mesenchymal cells seems to be precisely and spatiotemporally controlled, and the glucose uptake mediated by GLUT1 plays a crucial role in the early tooth morphogenesis and tooth size determination. Copyright © 2011 Elsevier Inc. All rights reserved.

  12. Tooth development in Ambystoma mexicanum: phosphatase activities, calcium accumulation and cell proliferation in the tooth-forming tissues.

    PubMed

    Wistuba, Joachim; Ehmcke, Jens; Clemen, Günter

    2003-06-01

    Prerequisites of tooth formation, cell proliferation in the tooth-forming tissues, calcium accumulation and the enzymatic activities of alkaline (ALP) and acid phosphatases (ACP) were investigated by immunohistochemical and histochemical methods in various developmental stages of the Mexican Axolotl, Ambystoma mexicanum. During the growth of replacement teeth, the tooth-forming tissues continually recruit cells from the surrounding regions. The basal layer of the oral epithelium, the dental lamina and sometimes even the outer enamel epithelium provide cells for the differentiated inner enamel epithelium, in which the active ameloblasts are localized. The differentiating odontoblasts are derived from proliferating cells situated basally to the replacement teeth in the mesenchymal tissue. When differentiation has started and the cells have become functional, proliferative activity can no longer be observed. Calcium is accumulated close to the site of mineralization in the inner enamel epithelium and in the odontoblasts as it is in mammals, elasmobranchii and teleostei. The activities of ACP and ALP related to the mineralization of the replacement teeth are separated spatially and not sequentially as they are in mammals. However, the results indicate a similar function of these enzymatic components in relation to tooth formation and maturation of mineral deposition. Most of the substantial processes related to tooth formation reported from other vertebrates occur in a manner similar to that in Ambystoma mexicanum, but there also seem to be basic mechanisms present that are realised in a unique way in this urodele.

  13. RNA-binding protein TIAR is essential for primordial germ cell development.

    PubMed

    Beck, A R; Miller, I J; Anderson, P; Streuli, M

    1998-03-03

    Primordial germ cells (PGCs) give rise to both eggs and sperm via complex maturational processes that require both cell migration and proliferation. However, little is known about the genes controlling gamete formation during the early stages of PGC development. Although several mutations are known to severely reduce the number of PGCs reaching and populating the genital ridges, the molecular identity of only two of these genes is known: the c-kit receptor protein tyrosine kinase and the c-kit ligand (the steel factor). Herein, we report that mutant mice lacking TIAR, an RNA recognition motif/ribonucleoprotein-type RNA-binding protein highly expressed in PGCs, fail to develop spermatogonia or oogonia. This developmental defect is a consequence of reduced survival of PGCs that migrate to the genital ridge around embryonic day 11.5 (E11.5). The numbers of PGCs populating the genital ridge in TIAR-deficient embryos are severely reduced compared to wild-type embryos by E11.5 and in the mutants PGCs are completely absent at E13.5. Furthermore, TIAR-deficient embryonic stem cells do not proliferate in the absence of exogenous leukemia inhibitory factor in an in vitro methylcellulose culture assay, supporting a role for TIAR in regulating cell proliferation. Because the development of PGCs relies on the action of several growth factors, these results are consistent with a role for TIAR in the expression of a survival factor or survival factor receptor that is essential for PGC development. TIAR-deficient mice thus provide a model system to study molecular mechanisms of PGC development and possibly the basis for some forms of idiopathic infertility.

  14. Risk factors for developing tooth sensitivity and gingival irritation associated with nightguard vital bleaching.

    PubMed

    Leonard, R H; Haywood, V B; Phillips, C

    1997-08-01

    The purpose of this study was to determine risk factors in the development of tooth sensitivity and gingival irritation associated with the nightguard vital bleaching technique. The potential risk factors evaluated (sex, age, reported allergy, whitening solution, number of times the solution was changed daily [its usage pattern], and dental arch) were collected from the daily log form turned in by each of the 64 participants after completion of the 6-week lightening process. Also evaluated for each participant, from color slides, were tooth characteristics such as gingival recession, defective restorations, abfraction lesions, enamel-cementum abrasion, etc, and reported side effects. The generalized Mantel-Haenszel statistic was used to assess the association between the potential risk factors and the development of tooth sensitivity and/or gingival irritation. No statistical relationship existed between age, sex, allergy, tooth characteristics, or the dental arch lightened and the development of side effects. Initially, a statistically significant association existed between side effects and the whitening solution used. However, when the analysis was controlled for usage pattern, this relationship disappeared. Patients who changed the whitening solution more than once a day reported statistically significantly more side effects than did those who did not change the whitening solution during their usage time.

  15. Growth and development of permanent teeth germ of transplacental Yu-Cheng babies in Taiwan

    SciTech Connect

    Lan, Shoujen; Yen, Yeayin; Ko, Yingchin; Chen, Engrin )

    1989-06-01

    This paper is intended to present a study of transplacental Yu-Cheng babies in Taiwan. The focus of the study is to demonstrate how a contaminated food source can affect the growth and development of permanent teeth germ in children. A sporadic outbreak of a peculiar skin disease was reported in Japan in October of 1968. An epidemiological study revealed the outbreak of this disease was caused by contaminated Kanemi rice oil. This episode of rice oil poisoned with polychlorinated biphenyls (PCB) was the first reported outbreak of PCB poisoning in the world. A second episode occurred in central Taiwan eleven years after the Japanese episode. Registered data from the Taiwan Provincial Government Health Department reported 1,843 cases in 1980. Of this group, more than 800 women were child-bearing age and most of these women would or soon would be married and pregnant. The offsprings of these women were in danger, because it has been proven that PCB intoxication could affect the fetus. These babies, only contaminated through the placenta, are called PCB transplacental Yusho babies in Japan and PCB transplacental Yu-Cheng babies in Taiwan. Babies with PCB poisoning could have Fetal PCB syndrome (FPS) and may have retarded eruption of permanent teeth and other anomalies such as reduced numbers of teeth and abnormal shaped roots. The study of transplacental Yu-Cheng babies is an important public health issue for Taiwan. Although there may be other issues, this study focuses only on the growth and development of permanent teeth of those babies affected by PCB transplacental contamination.

  16. Rad54 is required for the normal development of male and female germ cells and contributes to the maintainance of their genome integrity after genotoxic stress

    PubMed Central

    Messiaen, S; Le Bras, A; Duquenne, C; Barroca, V; Moison, D; Déchamps, N; Doussau, M; Bauchet, A-L; Guerquin, M-J; Livera, G; Essers, J; Kanaar, R; Habert, R; Bernardino-Sgherri, J

    2013-01-01

    Rad54 is an important factor in the homologous recombination pathway of DNA double-strand break repair. However, Rad54 knockout (KO) mice do not exhibit overt phenotypes at adulthood, even when exposed to radiation. In this study, we show that in Rad54 KO mouse the germline is actually altered. Compared with the wild-type (WT) animals, these mice have less premeiotic germ cells. This germ cell loss is found as early as in E11.5 embryos, suggesting an early failure during mutant primordial germ cells development. Both testicular and ovarian KO germ cells exhibited high radiation sensitivity leading to a long-term gametogenesis defect at adulthood. The KO female germline was particularly affected displaying decreased litter size or sterility. Spermatogenesis recovery after irradiation was slower and incomplete in Rad54 KO mice compared with that of WT mice, suggesting that loss of germ stem cell precursors is not fully compensated along the successive rounds of spermatogenesis. Finally, spermatogenesis recovery after postnatal irradiation is in part regulated by glial-cell-line-derived neurotrophic factor (GDNF) in KO but not in irradiated WT mice, suggesting that Sertoli cell GDNF production is stimulated upon substantial germ cell loss only. Our findings suggest that Rad54 has a key function in maintaining genomic integrity of the developing germ cells. PMID:23949223

  17. Rad54 is required for the normal development of male and female germ cells and contributes to the maintainance of their genome integrity after genotoxic stress.

    PubMed

    Messiaen, S; Le Bras, A; Duquenne, C; Barroca, V; Moison, D; Déchamps, N; Doussau, M; Bauchet, A L; Guerquin, M J; Livera, G; Essers, J; Kanaar, R; Habert, R; Bernardino-Sgherri, J

    2013-08-15

    Rad54 is an important factor in the homologous recombination pathway of DNA double-strand break repair. However, Rad54 knockout (KO) mice do not exhibit overt phenotypes at adulthood, even when exposed to radiation. In this study, we show that in Rad54 KO mouse the germline is actually altered. Compared with the wild-type (WT) animals, these mice have less premeiotic germ cells. This germ cell loss is found as early as in E11.5 embryos, suggesting an early failure during mutant primordial germ cells development. Both testicular and ovarian KO germ cells exhibited high radiation sensitivity leading to a long-term gametogenesis defect at adulthood. The KO female germline was particularly affected displaying decreased litter size or sterility. Spermatogenesis recovery after irradiation was slower and incomplete in Rad54 KO mice compared with that of WT mice, suggesting that loss of germ stem cell precursors is not fully compensated along the successive rounds of spermatogenesis. Finally, spermatogenesis recovery after postnatal irradiation is in part regulated by glial-cell-line-derived neurotrophic factor (GDNF) in KO but not in irradiated WT mice, suggesting that Sertoli cell GDNF production is stimulated upon substantial germ cell loss only. Our findings suggest that Rad54 has a key function in maintaining genomic integrity of the developing germ cells.

  18. Development of a behavior model of pain induced by experimental tooth movement in rats.

    PubMed

    Yang, Zhi; Luo, Wei; Hou, Jingqiu; Zhao, Zhihe; Jian, Fan; Wamalwa, Peter; Lai, Wenli; Wang, Jing; Wang, Yan; Liao, Zhenyu

    2009-08-01

    The mechanism of orthodontic pain and discomfort is poorly understood partly because of the limited number of animal behavioral models for pain assessment. This study aimed to develop a behavioral model for assessment of tooth-movement pain in rats using directed face-grooming activity. Male Sprague-Dawley rats weighing 200-300 g were used. They were videotaped on days 1, 3, 5, 7, and 14 after experimental tooth movement and their directed face-grooming behavior was evaluated. In addition, we also evaluated behavioral responses to the application of a progressively higher magnitude force and to multiple applications of an equal magnitude force. Finally, the effects of peripherally and systemically administered morphine and of the N-methyl-d-aspartate (NMDA) receptor antagonist, MK-801, on the behavioral responses were evaluated. The results indicated that time spent on directed face-grooming activity increased dramatically after initiating experimental tooth movement. The change concurred with the initial orthodontic pain response. This behavioral change was reproducible and was related to force magnitude. Application of both systemic and peripheral morphine and MK-801 could exert an analgesic effect on this pain model. These results suggest that directed face-grooming behavior can be a reliable measure for tooth-movement pain in rats, which could be widely used in investigating the orthodontic pain mechanism.

  19. Repression of the soma-specific transcriptome by Polycomb-repressive complex 2 promotes male germ cell development

    PubMed Central

    Mu, Weipeng; Starmer, Joshua; Fedoriw, Andrew M.; Yee, Della; Magnuson, Terry

    2014-01-01

    Polycomb-repressive complex 2 (PRC2) catalyzes the methylation of histone H3 Lys27 (H3K27) and functions as a critical epigenetic regulator of both stem cell pluripotency and somatic differentiation, but its role in male germ cell development is unknown. Using conditional mutagenesis to remove the core PRC2 subunits EED and SUZ12 during male germ cell development, we identified a requirement for PRC2 in both mitotic and meiotic germ cells. We observed a paucity of mutant spermatogonial stem cells (SSCs), which appears independent of repression of the known cell cycle inhibitors Ink4a/Ink4b/Arf. Moreover, mutant spermatocytes exhibited ectopic expression of somatic lamins and an abnormal distribution of SUN1 proteins on the nuclear envelope. These defects were coincident with abnormal chromosome dynamics, affecting homologous chromosome pairing and synapsis. We observed acquisition of H3K27me3 on stage-specific genes during meiotic progression, indicating a requirement for PRC2 in regulating the meiotic transcriptional program. Together, these data demonstrate that transcriptional repression of soma-specific genes by PRC2 facilitates homeostasis and differentiation during mammalian spermatogenesis. PMID:25228648

  20. Development and evolution of dentition pattern and tooth order in the skates and rays (batoidea; chondrichthyes).

    PubMed

    Underwood, Charlie J; Johanson, Zerina; Welten, Monique; Metscher, Brian; Rasch, Liam J; Fraser, Gareth J; Smith, Moya Meredith

    2015-01-01

    Shark and ray (elasmobranch) dentitions are well known for their multiple generations of teeth, with isolated teeth being common in the fossil record. However, how the diverse dentitions characteristic of elasmobranchs form is still poorly understood. Data on the development and maintenance of the dental patterning in this major vertebrate group will allow comparisons to other morphologically diverse taxa, including the bony fishes, in order to identify shared pattern characters for the vertebrate dentition as a whole. Data is especially lacking from the Batoidea (skates and rays), hence our objective is to compile data on embryonic and adult batoid tooth development contributing to ordering of the dentition, from cleared and stained specimens and micro-CT scans, with 3D rendered models. We selected species (adult and embryonic) spanning phylogenetically significant batoid clades, such that our observations may raise questions about relationships within the batoids, particularly with respect to current molecular-based analyses. We include developmental data from embryos of recent model organisms Leucoraja erinacea and Raja clavata to evaluate the earliest establishment of the dentition. Characters of the batoid dentition investigated include alternate addition of teeth as offset successional tooth rows (versus single separate files), presence of a symphyseal initiator region (symphyseal tooth present, or absent, but with two parasymphyseal teeth) and a restriction to tooth addition along each jaw reducing the number of tooth families, relative to addition of successor teeth within each family. Our ultimate aim is to understand the shared characters of the batoids, and whether or not these dental characters are shared more broadly within elasmobranchs, by comparing these to dentitions in shark outgroups. These developmental morphological analyses will provide a solid basis to better understand dental evolution in these important vertebrate groups as well as the

  1. Development and Evolution of Dentition Pattern and Tooth Order in the Skates And Rays (Batoidea; Chondrichthyes)

    PubMed Central

    Underwood, Charlie J.; Johanson, Zerina; Welten, Monique; Metscher, Brian; Rasch, Liam J.; Fraser, Gareth J.; Smith, Moya Meredith

    2015-01-01

    Shark and ray (elasmobranch) dentitions are well known for their multiple generations of teeth, with isolated teeth being common in the fossil record. However, how the diverse dentitions characteristic of elasmobranchs form is still poorly understood. Data on the development and maintenance of the dental patterning in this major vertebrate group will allow comparisons to other morphologically diverse taxa, including the bony fishes, in order to identify shared pattern characters for the vertebrate dentition as a whole. Data is especially lacking from the Batoidea (skates and rays), hence our objective is to compile data on embryonic and adult batoid tooth development contributing to ordering of the dentition, from cleared and stained specimens and micro-CT scans, with 3D rendered models. We selected species (adult and embryonic) spanning phylogenetically significant batoid clades, such that our observations may raise questions about relationships within the batoids, particularly with respect to current molecular-based analyses. We include developmental data from embryos of recent model organisms Leucoraja erinacea and Raja clavata to evaluate the earliest establishment of the dentition. Characters of the batoid dentition investigated include alternate addition of teeth as offset successional tooth rows (versus single separate files), presence of a symphyseal initiator region (symphyseal tooth present, or absent, but with two parasymphyseal teeth) and a restriction to tooth addition along each jaw reducing the number of tooth families, relative to addition of successor teeth within each family. Our ultimate aim is to understand the shared characters of the batoids, and whether or not these dental characters are shared more broadly within elasmobranchs, by comparing these to dentitions in shark outgroups. These developmental morphological analyses will provide a solid basis to better understand dental evolution in these important vertebrate groups as well as the

  2. The development of a "Green" aqueous enzymatic process to extract corn oil from corn germ

    USDA-ARS?s Scientific Manuscript database

    Approximately 2.4 million tons of commercial corn oil were produced worldwide in 2012, compared to 2012 world production of palm oil (53.3 MT) and soybean oil (43.1 MT) according to FAS, USDA. Most commercial corn oil (~90%) is produced from corn germ that is expeller pressed and/or hexane extracte...

  3. The development of dentotropic micelles with biodegradable tooth-binding moieties.

    PubMed

    Chen, Fu; Jia, Zhenshan; Rice, Kelly C; Reinhardt, Richard A; Bayles, Kenneth W; Wang, Dong

    2013-11-01

    Development of dentotropic (tooth-binding) micelle formulations to improved efficacy and safety of antimicrobial therapy for dental plaque prevention and treatment. Because of their excellent biocompatibility and biodegradability, diphosphoserine peptide and pyrophosphate were selected as the tooth-binding moieties to replace alendronate, which was used previously. Diphosphoserine peptide was conjugated to Pluronic P123 using "click" chemistry, whereas pyrophosphate was attached to P123 through an ester bond. The tooth-binding micelles (TBMs) were prepared by self-assembly of the modified P123 with the antimicrobial agent triclosan. The influence of human saliva and/or its components on TBMs' drug-releasing profile, tooth-binding potential and binding stability was evaluated in vitro. S. mutans UA159 biofilm formed on hydroxyapatite (HA) discs was used to evaluate the TBMs' therapeutic potential. Saliva does not affect triclosan release from TBMs. More than 60% of TBMs' HA binding capacity was maintained in the presence of saliva. Less than 5% of TBMs bound to HA was released over 24 h in human saliva, protease or phosphatase, suggesting the retention properties of the TBMs will not be compromised due to the biodegradable nature of the binding moieties. In both in vitro biofilm prevention and treatment studies, the TBM treated group showed significantly lower CFU per HA disc compared to the controls (2-log reduction, p < 0.05). The data from these studies suggest that the novel dentotropic micelle formulations bearing biodegradable tooth-binding moieties can be used as an effective and safe delivery tool for antimicrobials to improve dental plaque prevention and treatment.

  4. [Development of a screening scale for children at risk of baby bottle tooth decay].

    PubMed

    Khadra-Eid, J; Baudet, D; Fourny, M; Sellier, E; Brun, C; François, P

    2012-03-01

    Baby bottle tooth decay is a severe form of early childhood caries. This study aims to elaborate a screening tool for at risk children in order to facilitate primary prevention. A case-control study was conducted among children suffering from baby bottle tooth decay and children with no dental caries. Cases were children aged 5 years or less at diagnosis who experienced at least four caries with one or more affecting maxillary incisors. Controls were children matched for age and sex. Parents were interviewed by phone about their child's exposure to potential risk factors. We included 88 children suffering from baby bottle tooth decay and 88 children with no dental caries. In multivariate analysis, low social class (OR 6.39 [95% CI, 1.45-28.11]), prolonged bottle feeding or bedtime feeding (OR 153.2 [95% CI, 11.77-1994.96]), and snacking (OR 5.94 [95% CI, 1.35-26.2]) were significantly associated with baby bottle tooth decay. Regular dental visits were a significant protecting factor (OR 0.13 [95% CI, 0.02-0.77]). A score was developed using these significant risk factors and tested on the survey population. The mean score was 13/20 for cases and 4/20 for controls. These results are in accordance with the literature, except for brushing teeth, which was not significantly associated with baby bottle tooth decay in our study. A screening scale with a score of 20 points was proposed. Future validation is required. Pediatricians and general practitioners should encourage parents to change their habits. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

  5. Signaling through the TGF Beta-Activin Receptors ALK4/5/7 Regulates Testis Formation and Male Germ Cell Development

    PubMed Central

    Stringer, Jessica M.; van den Bergen, Jocelyn A.; Wilhelm, Dagmar; Sinclair, Andrew H.; Western, Patrick S.

    2013-01-01

    The developing testis provides an environment that nurtures germ cell development, ultimately ensuring spermatogenesis and fertility. Impacts on this environment are considered to underlie aberrant germ cell development and formation of germ cell tumour precursors. The signaling events involved in testis formation and male fetal germ cell development remain largely unknown. Analysis of knockout mice lacking single Tgfβ family members has indicated that Tgfβ's are not required for sex determination. However, due to functional redundancy, it is possible that additional functions for these ligands in gonad development remain to be discovered. Using FACS purified gonadal cells, in this study we show that the genes encoding Activin's, TGFβ's, Nodal and their respective receptors, are expressed in sex and cell type specific patterns suggesting particular roles in testis and germ cell development. Inhibition of signaling through the receptors ALK4, ALK5 and ALK7, and ALK5 alone, demonstrated that TGFβ signaling is required for testis cord formation during the critical testis-determining period. We also show that signaling through the Activin/NODAL receptors, ALK4 and ALK7 is required for promoting differentiation of male germ cells and their entry into mitotic arrest. Finally, our data demonstrate that Nodal is specifically expressed in male germ cells and expression of the key pluripotency gene, Nanog was significantly reduced when signaling through ALK4/5/7 was blocked. Our strategy of inhibiting multiple Activin/NODAL/TGFβ receptors reduces the functional redundancy between these signaling pathways, thereby revealing new and essential roles for TGFβ and Activin signaling during testis formation and male germ cell development. PMID:23342175

  6. bmp2b and bmp4 are dispensable for zebrafish tooth development.

    PubMed

    Wise, Sarah B; Stock, David W

    2010-10-01

    Bone morphogenetic protein (Bmp) signaling has been shown to play important roles in tooth development at virtually all stages from initiation to hard tissue formation. The specific ligands involved in these processes have not been directly tested by loss-of-function experiments, however. We used morpholino antisense oligonucleotides and mutant analysis in the zebrafish to reduce or eliminate the function of bmp2b and bmp4, two ligands known to be expressed in zebrafish teeth and whose mammalian orthologs are thought to play important roles in tooth development. Surprisingly, we found that elimination of function of these two genes singly and in combination did not prevent the formation of mature, attached teeth. The mostly likely explanation for this result is functional redundancy with other Bmp ligands, which may differ between the zebrafish and the mouse.

  7. Mechanism of cadmium induced crystal defects in developing rat tooth enamel.

    PubMed

    Kakei, Mitsuo; Sakae, Toshiro; Yoshikawa, Masayoshi

    2009-01-01

    It is well known that exposure to environmental cadmium causes itai-itai (ouch-ouch) disease. However, the exact mechanism underlying this bone disease remains unresolved. By focusing on the calcification mechanism, we examined developing tooth enamel in rats exposed to cadmium to test the hypothesis that cadmium exposure may cause defects in crystal formation. Electron microscopy revealed the presence of perforated crystals in developing tooth enamel, indicating that the process of crystal nucleation may have been interrupted by cadmium exposure. Furthermore, biochemical analyses revealed that the catalytic activity of carbonic anhydrase in the immature enamel matrix declined remarkably despite the fact that quantitative reduction of this enzyme was insignificant, suggesting that the decline of catalytic activity may have resulted from the replacement of zinc with cadmium ions. Therefore, we concluded that the poor catalytic activity of cadmium-binding carbonic anhydrase might hinder the nucleation process, leading to an impairment in mineralization that causes itai-itai disease.

  8. Mechanism of cadmium induced crystal defects in developing rat tooth enamel

    PubMed Central

    Kakei, Mitsuo; Sakae, Toshiro; Yoshikawa, Masayoshi

    2009-01-01

    It is well known that exposure to environmental cadmium causes itai-itai (ouch-ouch) disease. However, the exact mechanism underlying this bone disease remains unresolved. By focusing on the calcification mechanism, we examined developing tooth enamel in rats exposed to cadmium to test the hypothesis that cadmium exposure may cause defects in crystal formation. Electron microscopy revealed the presence of perforated crystals in developing tooth enamel, indicating that the process of crystal nucleation may have been interrupted by cadmium exposure. Furthermore, biochemical analyses revealed that the catalytic activity of carbonic anhydrase in the immature enamel matrix declined remarkably despite the fact that quantitative reduction of this enzyme was insignificant, suggesting that the decline of catalytic activity may have resulted from the replacement of zinc with cadmium ions. Therefore, we concluded that the poor catalytic activity of cadmium-binding carbonic anhydrase might hinder the nucleation process, leading to an impairment in mineralization that causes itai-itai disease. PMID:20009383

  9. Impairment of Bony Crypt Development Associated With Hexavalent Chromium Exposure During Tooth Eruption.

    PubMed

    Sánchez, Luciana M; Lewicki, Marianela; De Lucca, Romina C; Ubios, Ángela M

    2015-12-01

    Improperly treated hexavalent chromium-containing industrial wastes contaminate drinking water, potentially affecting children taking breast milk or baby bottles prepared with infant formula. Thus, the aim of the present work was to determine the effect of this toxic on bone activity in the developing alveolus during tooth eruption of suckling Wistar rats intoxicated with potassium dichromate. Experimental animals received a daily dose of 12.5mg/kg body weight of potassium dichromate by gavage for 10 days; controls received an equivalent volume of saline solution. Histologic and histomorphometric studies of the mandible were performed. The data were statistically analyzed using Student's t test; statistical significance was set at a value of p <0.05. Experimental animals exhibited delayed tooth eruption, decreased periodontal width and bone volume, a lower percentage of bone formation surfaces, and higher percentage of quiescent surfaces (p<0.05) compared to controls. The delay in tooth eruption observed after exposure to hexavalent chromium is the result of a lower rate of bone remodeling in the developing alveolus. The obtained results show the importance of controlling toxic substances in drinking water, since their effects may alter the growth and development of subjects who were exposed during early infancy.

  10. Dental Stem Cell in Tooth Development and Advances of Adult Dental Stem Cell in Regenerative Therapies.

    PubMed

    Tan, Jiali; Xu, Xin; Lin, Jiong; Fan, Li; Zheng, Yuting; Kuang, Wei

    2015-01-01

    Stem cell-based therapies are considered as a promising treatment for many clinical usage such as tooth regeneration, bone repairation, spinal cord injury, and so on. However, the ideal stem cell for stem cell-based therapy still remains to be elucidated. In the past decades, several types of stem cells have been isolated from teeth, including dental pulp stem cells (DPSCs), stem cells from human exfoliated deciduous teeth (SHED), periodontal ligament stem cells (PDLSCs), dental follicle progenitor stem cells (DFPCs) and stem cells from apical papilla (SCAP), which may be a good source for stem cell-based therapy in certain disease, especially when they origin from neural crest is considered. In this review, the specific characteristics and advantages of the adult dental stem cell population will be summarized and the molecular mechanisms of the differentiation of dental stem cell during tooth development will be also discussed.

  11. Highly variable recessive lethal or nearly lethal mutation rates during germ-line development of male Drosophila melanogaster.

    PubMed

    Gao, Jian-Jun; Pan, Xue-Rong; Hu, Jing; Ma, Li; Wu, Jian-Min; Shao, Ye-Lin; Barton, Sara A; Woodruff, Ronny C; Zhang, Ya-Ping; Fu, Yun-Xin

    2011-09-20

    Each cell of higher organism adults is derived from a fertilized egg through a series of divisions, during which mutations can occur. Both the rate and timing of mutations can have profound impacts on both the individual and the population, because mutations that occur at early cell divisions will affect more tissues and are more likely to be transferred to the next generation. Using large-scale multigeneration screening experiments for recessive lethal or nearly lethal mutations of Drosophila melanogaster and recently developed statistical analysis, we show for male D. melanogaster that (i) mutation rates (for recessive lethal or nearly lethal) are highly variable during germ cell development; (ii) first cell cleavage has the highest mutation rate, which drops substantially in the second cleavage or the next few cleavages; (iii) the intermediate stages, after a few cleavages to right before spermatogenesis, have at least an order of magnitude smaller mutation rate; and (iv) spermatogenesis also harbors a fairly high mutation rate. Because germ-line lineage shares some (early) cell divisions with somatic cell lineage, the first conclusion is readily extended to a somatic cell lineage. It is conceivable that the first conclusion is true for most (if not all) higher organisms, whereas the other three conclusions are widely applicable, although the extent may differ from species to species. Therefore, conclusions or analyses that are based on equal mutation rates during development should be taken with caution. Furthermore, the statistical approach developed can be adopted for studying other organisms, including the human germ-line or somatic mutational patterns.

  12. Identification of Potential Germ-Cell Mutagens

    EPA Science Inventory

    The existence of agents that can induce germ-cell mutations in experimental systems has been recognized since 1927 with the discovery of the ability of X-rays to induce such mutations in Drosophila. Various rodent-based germ-cell mutation assays have been developed, and ~50 germ...

  13. Extraction and characterization of corn germ proteins

    USDA-ARS?s Scientific Manuscript database

    Our study was conducted to develop methods to extract corn germ protein economically and characterize and identify potential applications of the recovered protein. Protein was extracted from both wet germ and finished (dried) germ using 0.1M NaCl as solvent. The method involved homogenization, sti...

  14. Identification of Potential Germ-Cell Mutagens

    EPA Science Inventory

    The existence of agents that can induce germ-cell mutations in experimental systems has been recognized since 1927 with the discovery of the ability of X-rays to induce such mutations in Drosophila. Various rodent-based germ-cell mutation assays have been developed, and ~50 germ...

  15. Switching of dominant retrotransposon silencing strategies from posttranscriptional to transcriptional mechanisms during male germ-cell development in mice

    PubMed Central

    Inoue, Kota; Fukuda, Kei; Sasaki, Hiroyuki

    2017-01-01

    Mammalian genomes harbor millions of retrotransposon copies, some of which are transpositionally active. In mouse prospermatogonia, PIWI-interacting small RNAs (piRNAs) combat retrotransposon activity to maintain the genomic integrity. The piRNA system destroys retrotransposon-derived RNAs and guides de novo DNA methylation at some retrotransposon promoters. However, it remains unclear whether DNA methylation contributes to retrotransposon silencing in prospermatogonia. We have performed comprehensive studies of DNA methylation and polyA(+) RNAs (transcriptome) in developing male germ cells from Pld6/Mitopld and Dnmt3l knockout mice, which are defective in piRNA biogenesis and de novo DNA methylation, respectively. The Dnmt3l mutation greatly reduced DNA methylation levels at most retrotransposons, but its impact on their RNA abundance was limited in prospermatogonia. In Pld6 mutant germ cells, although only a few retrotransposons exhibited reduced DNA methylation, many showed increased expression at the RNA level. More detailed analysis of RNA sequencing, nascent RNA quantification, profiling of cleaved RNA ends, and the results obtained from double knockout mice suggest that PLD6 works mainly at the posttranscriptional level. The increase in retrotransposon expression was larger in Pld6 mutants than it was in Dnmt3l mutants, suggesting that RNA degradation by the piRNA system plays a more important role than does DNA methylation in prospermatogonia. However, DNA methylation had a long-term effect: hypomethylation caused by the Pld6 or Dnmt3l mutation resulted in increased retrotransposon expression in meiotic spermatocytes. Thus, posttranscriptional silencing plays an important role in the early stage of germ cell development, then transcriptional silencing becomes important in later stages. In addition, intergenic and intronic retrotransposon sequences, in particular those containing the antisense L1 promoters, drove ectopic expression of nearby genes in both

  16. Melatonin promotes development of haploid germ cells from early developing spermatogenic cells of Suffolk sheep under in vitro condition.

    PubMed

    Deng, Shou-Long; Chen, Su-Ren; Wang, Zhi-Peng; Zhang, Yan; Tang, Ji-Xin; Li, Jian; Wang, Xiu-Xia; Cheng, Jin-Mei; Jin, Cheng; Li, Xiao-Yu; Zhang, Bao-Lu; Yu, Kun; Lian, Zheng-Xing; Liu, Guo-Shi; Liu, Yi-Xun

    2016-05-01

    Promotion of spermatogonial stem cell (SSC) differentiation into functional sperms under in vitro conditions is a great challenge for reproductive physiologists. In this study, we observed that melatonin (10(-7) M) supplementation significantly enhanced the cultured SSCs differentiation into haploid germ cells. This was confirmed by the expression of sperm special protein, acrosin. The rate of SSCs differentiation into sperm with melatonin supplementation was 11.85 ± 0.93% which was twofold higher than that in the control. The level of testosterone, the transcriptions of luteinizing hormone receptor (LHR), and the steroidogenic acute regulatory protein (StAR) were upregulated with melatonin treatment. At the early stage of SSCs culture, melatonin suppressed the level of cAMP, while at the later stage, it promoted cAMP production. The similar pattern was observed in testosterone content. Expressions for marker genes of meiosis anaphase, Dnmt3a, and Bcl-2 were upregulated by melatonin. In contrast, Bax expression was downregulated. Importantly, the in vitro-generated sperms were functional and they were capable to fertilize oocytes. These fertilized oocytes have successfully developed to the blastula stage.

  17. Involvement of doublesex and mab-3-related transcription factors in human female germ cell development demonstrated by xenograft and interference RNA strategies.

    PubMed

    Poulain, Marine; Frydman, Nelly; Tourpin, Sophie; Muczynski, Vincent; Mucsynski, Vincent; Souquet, Benoit; Benachi, Alexandra; Habert, René; Rouiller-Fabre, Virginie; Livera, Gabriel

    2014-10-01

    We identified three doublesex and mab-3-related transcription factors (DMRT) that were sexually differentially expressed in human fetal gonads and present in the ovaries at the time of meiotic initiation. These were also identified in murine embryonic female germ cells. Among these, we focused on DMRTA2 (DMRT5), whose function is unknown in the developing gonads, and clarified its role in human female fetal germ cells, using an original xenograft model. Early human fetal ovaries (8-11 weeks post-fertilization) were grafted into nude mice. Grafted ovaries developed normally, with no apparent overt changes, when compared with ungrafted ovaries at equivalent developmental stages. Appropriate germ cell density, mitotic/meiotic transition, markers of meiotic progression and follicle formation were evident. Four weeks after grafting, mice were treated with siRNA, specifically targeting human DMRTA2 mRNA. DMRTA2 inhibition triggered an increase in undifferentiated FUT4-positive germ cells and a decrease in the percentage of meiotic γH2AX-positive germ cells, when compared with mice that were injected with control siRNA. Interestingly, the expression of markers associated with pre-meiotic germ cell differentiation was also impaired, as was the expression of DMRTB1 (DMRT6) and DMRTC2 (DMRT7). This study reveals, for the first time, the requirement of DMRTA2 for normal human female embryonic germ cell development. DMRTA2 appears to be necessary for proper differentiation of oogonia, prior to entry into meiosis, in the human species. Additionally, we developed a new model of organ xenografting, coupled with RNA interference, which provides a useful tool for genetic investigations of human germline development. © The Author 2014. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  18. Extragonadal Germ Cell Cancer (EGC)

    MedlinePlus

    ... germ cells are first seen outside of the embryo in the yolk sac. At about 4 to ... weeks of development, these cells migrate into the embryo where they populate the developing testes or ovaries. ...

  19. Expression of Oct-4, SOX-2, and MYC in dental papilla cells and dental follicle cells during in-vivo tooth development and in-vitro co-culture.

    PubMed

    Peng, Zhengjun; Liu, Lu; Wei, Xi; Ling, Junqi

    2014-08-01

    During tooth development, the special structure of dental follicle and dental papilla enables dental papilla cells (DPCs) and dental follicle cells (DFCs) to make contact with each other. Octamer-binding transcription factor 4 (Oct-4), sex determining region Y box-2 (SOX-2), and cellular homologue of avian myelocytomatosis virus oncogene (MYC) (OSM) are associated with reprogramming and pluripotency. However, whether the expression of OSM could be activated through cell-cell communication is not known. In this study, the distribution of OSM in rat tooth germ was investigated by immunohistochemical staining. An in-vitro co-culture system of DPCs and DFCs was established. Cell proliferation, cell apoptosis, cell cycle stages, and expression of OSM were investigated by Cell Counting Kit 8 (CCK8) analysis, flow cytometry, real-time PCR, and immunohistochemical staining. We found that Oct-4 and SOX-2 were strongly expressed in tooth germ on days 7 and 9 after birth, whereas MYC was expressed only on day 9. Cell proliferation and apoptosis were inhibited, the cell cycle was arrested in the G0/G1 phase, and the propidium iodide (PI) value was downregulated. Expression of Oct-4 and SOX-2 was significantly elevated in both cell types after 3 d of co-culture, whereas expression of MYC was not significantly elevated until day 5. These results indicate that the optimized microenvironment with cell-cell communication enhanced the expression of reprogramming markers associated with reprogramming capacity in DPCs and DFCs, both in vivo and in vitro. © 2014 Eur J Oral Sci.

  20. Analysis of SOX2 expression in developing human testis and germ cell neoplasia.

    PubMed

    Sonne, Si B; Perrett, Rebecca M; Nielsen, John E; Baxter, Melissa A; Kristensen, David M; Leffers, Henrik; Hanley, Neil A; Rajpert-De-Meyts, Ewa

    2010-01-01

    The transcriptional regulators of pluripotency, POU5F1 (OCT4), NANOG and SOX2, are highly expressed in embryonal carcinoma (EC). In contrast to OCT4 and NANOG, SOX2 has not been demonstrated in the early human germ cell lineage or carcinoma in situ (CIS), the precursor for testicular germ cell tumours (TGCTs). Here, we have analysed SOX2 expression in CIS and overt TGCTs, as well as normal second and third trimester fetal, prepubertal and adult testes by in situ hybridisation and immunohistochemistry using three different antibodies. In contrast to earlier studies, we detected SOX2 mRNA in most CIS cells. We also detected speckled nuclear SOX2 immunoreactivity in CIS cells with one primary antibody, which was not apparent with other primary antibodies. The results demonstrate SOX2 gene expression in CIS for the first time and raise the possibility of post-transcriptional regulation, most likely sumoylation as a mechanism for limiting SOX2 action in these cells.

  1. Altered miRNA Signature of Developing Germ-cells in Infertile Patients Relates to the Severity of Spermatogenic Failure and Persists in Spermatozoa.

    PubMed

    Muñoz, Xavier; Mata, Ana; Bassas, Lluís; Larriba, Sara

    2015-12-09

    The aim of this study was to assess the cellular miRNA expression behaviour in testes with spermatogenic failure (SpF). We performed a high-throughput screen of 623 mature miRNAs by a quantitative RT-qPCR-based approach in histologically well-defined testicular samples with spermatogenic disruption at different germ-cell stages, which revealed altered patterns of miRNA expression. We focussed on the differentially expressed miRNAs whose expression correlated with the number of testicular mature germ-cells and described the combined expression values of a panel of three miRNAs (miR-449a, miR-34c-5p and miR-122) as a predictive test for the presence of mature germ-cells in testicular biopsy. Additionally, we determined decreased cellular miRNA content in developing germ-cells of SpF testis; this was more noticeable the earlier the stage of germ-cell differentiation was affected by maturation failure. Furthermore, we showed that the miRNA expression profile in mature sperm from mild SpF patients was widely altered. Our results suggest that the cellular miRNA content of developed germ-cells depends heavily on the efficacy of the spermatogenic process. What is more, spermatozoa that have fulfilled the differentiation process still retain the dysregulated miRNA pattern observed in the developing SpF germ-cells. This altered miRNA molecular signature may have functional implications for the male gamete.

  2. Changes in levels of plasminogen activator activity in normal and germ-cell-depleted testes during development.

    PubMed

    Lacroix, M; Smith, F E; Fritz, I B

    1982-05-01

    Levels of plasminogen activator activity were determined in testes obtained from normal and irradiated rats in various ages. During normal development, plasminogen activator activity per g testis increased rapidly between 40 and 60 days of age, but a comparable rise did not occur in germ-cell depleted testes of irradiated rats. Levels of enzyme in various populations of testicular cells were highest in Sertoli (varying between 1800 and 6300 units/mg protein in cell maintained under different culture conditions), and lowest in peritubular myoid cells (about 1 unit/mg protein), with intermediate levels in germinal cells (ranging between 147 and 560 units/Mg protein in residual bodies, spermatocytes and spermatids). No protease inhibitor could be detected in germ-cell extracts. The addition to the medium in which Sertoli cells were in culture of particles which can be phagocytosed (autoclaved E. coli) resulted in an increased formation of plasminogen activator activity by Sertoli cells. A synergistic enhancement of enzyme production resulted following the addition of submaximal quantities of dibutyryl cyclic AMP and autoclaved bacteria to sertoli cells in culture. On the basis of these data, we suggest that the presence of advanced germinal cells during gonadal development may stimulate the synthesis of plasminogen activator by Sertoli cells, mediated in part by the phagocytosis of residual bodies by sertoli cells which occurs prior to spermiation.

  3. Tooth structure studied using the atomic force microscope

    NASA Astrophysics Data System (ADS)

    Kasas, Sandor; Berdal, Ariane; Celio, Marco R.

    1993-06-01

    We used the atomic force microscope (AFM) to observe structure of the tooth, both rat and human. The rigidity and the surface flatness of thin sections of this mineralized tissue, allow us to attain good resolution with the AFM. As enamel contains uniquely large crystals of hydroxyapatite it can be investigated at high resolution. Tooth enamel and thin slices of undecalcified developing tooth germs from 2 - 12 day old rats were observed, embedded in acrylic resin (Lowicryl K4M). In addition, as orthophosphoric acid is widely used clinically to etch tooth enamel before restoring with composites, we studied its action at pH2 on the tooth surface during 1 hour of exposition. Hydroxyapatite crystals and collagen fibers were seen in the tooth slices observed in air, and the classical structure of the enamel was visible. The etched enamel surface under liquid, showed dramatic differences to that imaged in air. Modifications to the surface were also seen during exposure to the acid.

  4. Multiplex shRNA Screening of Germ Cell Development by in Vivo Transfection of Mouse Testis

    PubMed Central

    Ho, Nicholas R. Y.; Usmani, Abul R.; Yin, Yan; Ma, Liang; Conrad, Donald F.

    2016-01-01

    Spermatozoa are one of the few mammalian cell types that cannot be fully derived in vitro, severely limiting the application of modern genomic techniques to study germ cell biology. The current gold standard approach of characterizing single-gene knockout mice is slow as generation of each mutant line can take 6–9 months. Here, we describe an in vivo approach to rapid functional screening of germline genes based on a new nonsurgical, nonviral in vivo transfection method to deliver nucleic acids into testicular germ cells. By coupling multiplex transfection of short hairpin RNA (shRNA) constructs with pooled amplicon sequencing as a readout, we were able to screen many genes for spermatogenesis function in a quick and inexpensive experiment. We transfected nine mouse testes with a pilot pool of RNA interference (RNAi) against well-characterized genes to show that this system is highly reproducible and accurate. With a false negative rate of 18% and a false positive rate of 12%, this method has similar performance as other RNAi screens in the well-described Drosophila model system. In a separate experiment, we screened 26 uncharacterized genes computationally predicted to be essential for spermatogenesis and found numerous candidates for follow-up studies. Finally, as a control experiment, we performed a long-term selection screen in neuronal N2a cells, sampling shRNA frequencies at five sequential time points. By characterizing the effect of both libraries on N2a cells, we show that our screening results from testis are tissue-specific. Our calculations indicate that the current implementation of this approach could be used to screen thousands of protein-coding genes simultaneously in a single mouse testis. The experimental protocols and analysis scripts provided will enable other groups to use this procedure to study diverse aspects of germ cell biology ranging from epigenetics to cell physiology. This approach also has great promise as an applied tool for

  5. Stages and transitions in the development of tooth brushing skills in children of Mexican immigrant families: a qualitative study.

    PubMed

    Benadof, Dafna; Polk, Deborah; Documet, Patricia

    2015-01-01

    Compared with white children, the oral health of Latino children in the United States is much worse. One factor contributing to oral health is tooth brushing. Few studies have addressed the formation of the tooth brushing habit in children, and only one of them studied a Latino population. The purpose of this study is to explore the development of the tooth brushing habit in children of Mexican immigrant families and develop hypothesis based on its results. This is an exploratory qualitative study, with a case study design based on 20 in-depth interviews. Participants were Mexican immigrant mothers living in Pittsburgh and Philadelphia, PA. Participants had at least one child six-years-old or younger. Interviews were recorded, transcribed verbatim, and analyzed using qualitative analysis procedures. Four stages were identified in the tooth brushing learning process: initiation and entirely dependent tooth brushing, assisted tooth brushing, road to tooth brushing independence, and independent tooth brushing. Two factors influenced parents' teaching approaches: parents' perceptions of their child's achievement of physical, cognitive, and motor developmental milestones and parents' knowledge about oral hygiene. We identified four distinct stages and found evidence to hypothesize that transitions from one stage to the next are triggered not by the age of the child but by parents' knowledge about oral hygiene and their perceptions of their child's achievement of physical, cognitive, and motor developmental milestones. Future quantitative research studies should be conducted to test this hypothesis in larger groups of Latinos as well as other ethnic groups. © 2015 American Association of Public Health Dentistry.

  6. The role of evolutionarily conserved germ-line DH sequence in B-1 cell development and natural antibody production.

    PubMed

    Vale, Andre M; Nobrega, Alberto; Schroeder, Harry W

    2015-12-01

    Because of N addition and variation in the site of VDJ joining, the third complementarity-determining region of the heavy chain (CDR-H3) is the most diverse component of the initial immunoglobulin antigen-binding site repertoire. A large component of the peritoneal cavity B-1 cell component is the product of fetal and perinatal B cell production. The CDR-H3 repertoire is thus depleted of N addition, which increases dependency on germ-line sequence. Cross-species comparisons have shown that DH gene sequence demonstrates conservation of amino acid preferences by reading frame. Preference for reading frame 1, which is enriched for tyrosine and glycine, is created both by rearrangement patterns and by pre-BCR and BCR selection. In previous studies, we have assessed the role of conserved DH sequence by examining peritoneal cavity B-1 cell numbers and antibody production in BALB/c mice with altered DH loci. Here, we review our finding that changes in the constraints normally imposed by germ-line-encoded amino acids within the CDR-H3 repertoire profoundly affect B-1 cell development, especially B-1a cells, and thus natural antibody immunity. Our studies suggest that both natural and somatic selection operate to create a restricted B-1 cell CDR-H3 repertoire.

  7. Locus- and domain-dependent control of DNA methylation at mouse B1 retrotransposons during male germ cell development.

    PubMed

    Ichiyanagi, Kenji; Li, Yufeng; Li, Yungfeng; Watanabe, Toshiaki; Ichiyanagi, Tomoko; Fukuda, Kei; Kitayama, Junko; Yamamoto, Yasuhiro; Kuramochi-Miyagawa, Satomi; Nakano, Toru; Yabuta, Yukihiro; Seki, Yoshiyuki; Saitou, Mitinori; Sasaki, Hiroyuki

    2011-12-01

    In mammals, germ cells undergo striking dynamic changes in DNA methylation during their development. However, the dynamics and mode of methylation are poorly understood for short interspersed elements (SINEs) dispersed throughout the genome. We investigated the DNA methylation status of mouse B1 SINEs in male germ cells at different developmental stages. B1 elements showed a large locus-to-locus variation in methylation; loci close to RNA polymerase II promoters were hypomethylated, while most others were hypermethylated. Interestingly, a mutation that eliminates Piwi-interacting RNAs (piRNAs), which are involved in methylation of long interspersed elements (LINEs), did not affect the level of B1 methylation, implying a piRNA-independent mechanism. Methylation at B1 loci in SINE-poor genomic domains showed a higher dependency on the de novo DNA methyltransferase DNMT3A but not on DNMT3B, suggesting that DNMT3A plays a major role in methylation of these domains. We also found that many genes specifically expressed in the testis possess B1 elements in their promoters, suggesting the involvement of B1 methylation in transcriptional regulation. Taken altogether, our results not only reveal the dynamics and mode of SINE methylation but also suggest how the DNA methylation profile is created in the germline by a pair of DNA methyltransferases.

  8. Osteoadherin Accumulates in the Predentin towards the Mineralization Front in the Developing Tooth

    PubMed Central

    Nikdin, Hero; Olsson, Marie-Louise; Hultenby, Kjell; Sugars, Rachael V.

    2012-01-01

    Background Proteoglycans (PG) are known to be involved in the organization and assembly of the extracellular matrix (ECM) prior to mineral deposition. Osteoadherin (OSAD), a keratan sulphate PG is a member of the small leucine-rich (SLRP) family of PGs and unlike other SLRPs, OSAD expression is restricted to mineralized tissues. It is proposed to have a high affinity for hydroxyapatite and has been shown to be expressed by mature osteoblasts but its exact role remains to be elucidated. Methodology/Principal Findings We investigated the protein distribution of OSAD in the developing mouse tooth using immunohistochemistry and compared its expression with other SLRPs, biglycan (BGN), decorin (DCN) and fibromodulin (FMD). OSAD was found to be specifically localized in the predentin layer of the tooth and focused at the mineralization front. These studies were confirmed at the ultrastructural level using electron microscopy (iEM), where the distribution of immunogold labeled OSAD particles were quantified and significant amounts were found in the predentin, forming a gradient towards the mineralization front. In addition, iEM results revealed OSAD to lie in close association with collagen fibers, further suggesting an important role for OSAD in the organization of the ECM. The expression profile of mineralization-related SLRP genes by rat dental pulp cells exposed to mineralization inducing factors, showed an increase in all SLRP genes. Indeed, OSAD expression was significantly increased during the mineralization process, specifically following, matrix maturation, and finally mineral deposition. Alizarin Red S staining for calcium deposition showed clear bone-like nodules, which support matrix maturation and mineralization. Conclusions These studies provide new evidence for the role of OSAD in the mineralization process and its specific localization in the predentin layer accumulating at the mineralization front highlighting its role in tooth development. PMID:22355375

  9. Roles of RNA-binding Proteins and Post-transcriptional Regulation in Driving Male Germ Cell Development in the Mouse.

    PubMed

    Licatalosi, Donny D

    Tissue development and homeostasis are dependent on highly regulated gene expression programs in which cell-specific combinations of regulatory factors determine which genes are expressed and the post-transcriptional fate of the resulting RNA transcripts. Post-transcriptional regulation of gene expression by RNA-binding proteins has critical roles in tissue development-allowing individual genes to generate multiple RNA and protein products, and the timing, location, and abundance of protein synthesis to be finely controlled. Extensive post-transcriptional regulation occurs during mammalian gametogenesis, including high levels of alternative mRNA expression, stage-specific expression of mRNA variants, broad translational repression, and stage-specific activation of mRNA translation. In this chapter, an overview of the roles of RNA-binding proteins and the importance of post-transcriptional regulation in male germ cell development in the mouse is presented.

  10. mRNA translation during oocyte maturation plays a key role in development of primordial germ cells in Xenopus embryos.

    PubMed

    Zeynali, Bahman; Dixon, Keith E

    2004-09-01

    It is believed that cytoplasmic localization in the egg is necessary for development of primordial germ cells (PGCs) in Xenopus embryos. In this study, we sought to determine if translation of maternal mRNA during oocyte maturation is involved in the development of PGCs. Donor oocytes were collected from both stimulated (those who receive gonadotropin) and unstimulated females, artificially matured and fertilized using a host transfer technique. Using chloramphenicol (50 microM and 500 microM RNA), RNA translation was inhibited during oocyte maturation. Our results showed that in unstimulated embryos treated with 50 microM chloramphenicol, there was a significant reduction in the number of PGCs reaching genital ridges. In stimulated embryos, however, the number of PGCs was unchanged unless a higher concentration (500 microM) of chloramphenicol was used. From these results it is suggested that maternal mRNA translation during oocyte maturation plays a key role in development of PGCs.

  11. Tooth development and histology patterns in lamniform sharks (Elasmobranchii, Lamniformes) revisited.

    PubMed

    Schnetz, Lisa; Pfaff, Cathrin; Kriwet, Jürgen

    2016-12-01

    The dentition of lamniforme sharks exhibits several characters that have been used extensively to resolve the phylogenetic relationships of extant taxa, yet some uncertainties remain. Also, the development of different teeth of a tooth file within the jaws of most extant lamniforms has not been documented to date. High-resolution micro-computed tomography is used here to re-evaluate the importance of two dental characters within the order Lamniformes, which were considered not to be phylogenetically informative, the histotype and the number of teeth per tooth file. Additionally, the development and mineralization patterns of the teeth of the two osteodont lamniforms Lamna nasus and Alopias superciliosus were compared. We discuss the importance of these dental characters for phylogenetic interpretations to assess the quality of these characters in resolving lamniform relationships. The dental characters suggest that (1) Lamniformes are the only modern-level sharks exhibiting the osteodont histotype, (2) the osteodont histotype in lamniform sharks is a derived state in modern-level sharks (Elasmobranchii), (3) the osteodont type, conversely is convergently achieved when the clade Chondrichthyes is considered and thus might comprise a functional rather than a phylogenetic signal, and (4) there is an increase in the number of teeth per file throughout lamniform phylogeny. Structural development of the teeth of L. nasus and A. superciliosus is congruent with a previous investigation of the lamniform shark Carcharodon carcharias. J. Morphol. 277:1584-1598, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  12. Laser capture microdissection enables cellular and molecular studies of tooth root development

    PubMed Central

    Sun, Jian-Xun; Horst, Orapin V; Bumgarner, Roger; Lakely, Bryce; Somerman, Martha J; Zhang, Hai

    2012-01-01

    Epithelial–mesenchymal interactions (EMIs) are critical for tooth development. Molecular mechanisms mediating these interactions in root formation is not well understood. Laser capture microdissection (LCM) and subsequent microarray analyses enable large scale in situ molecular and cellular studies of root formation but to date have been hindered by technical challenges of gaining intact histological sections of non-decalcified mineralized teeth or jaws with well-preserved RNA. Here,we describe a new method to overcome this obstacle that permits LCM of dental epithelia,adjacent mesenchyme,odontoblasts and cementoblasts from mouse incisors and molars during root development. Using this method,we obtained RNA samples of high quality and successfully performed microarray analyses. Robust differences in gene expression,as well as genes not previously associated with root formation,were identified. Comparison of gene expression data from microarray with real-time reverse transcriptase polymerase chain reaction (RT-PCR) supported our findings. These genes include known markers of dental epithelia,mesenchyme,cementoblasts and odontoblasts,as well as novel genes such as those in the fibulin family. In conclusion,our new approach in tissue preparation enables LCM collection of intact cells with well-preserved RNA allowing subsequent gene expression analyses using microarray and RT-PCR to define key regulators of tooth root development. PMID:22422086

  13. Twist1 Is Essential for Tooth Morphogenesis and Odontoblast Differentiation*

    PubMed Central

    Meng, Tian; Huang, Yanyu; Wang, Suzhen; Zhang, Hua; Dechow, Paul C.; Wang, Xiaofang; Qin, Chunlin; Shi, Bing; D'Souza, Rena N.; Lu, Yongbo

    2015-01-01

    Twist1 is a basic helix-loop-helix-containing transcription factor that is expressed in the dental mesenchyme during the early stages of tooth development. To better delineate its roles in tooth development, we generated Twist1 conditional knockout embryos (Twist2Cre/+;Twist1fl/fl) by breeding Twist1 floxed mice (Twist1fl/fl) with Twist2-Cre recombinase knockin mice (Twist2Cre/+). The Twist2Cre/+;Twist1fl/fl embryos formed smaller tooth germs and abnormal cusps during early tooth morphogenesis. Molecular and histological analyses showed that the developing molars of the Twist2Cre/+;Twist1fl/fl embryos had reduced cell proliferation and expression of fibroblast growth factors 3, 4, 9, and 10 and FGF receptors 1 and 2 in the dental epithelium and mesenchyme. In addition, 3-week-old renal capsular transplants of embryonic day 18.5 Twist2Cre/+;Twist1fl/fl molars showed malformed crowns and cusps with defective crown dentin and enamel. Immunohistochemical analyses revealed that the implanted mutant molars had defects in odontoblast differentiation and delayed ameloblast differentiation. Furthermore, in vitro ChIP assays demonstrated that Twist1 was able to bind to a specific region of the Fgf10 promoter. In conclusion, our findings suggest that Twist1 plays crucial roles in regulating tooth development and that it may exert its functions through the FGF signaling pathway. PMID:26487719

  14. Twist1 Is Essential for Tooth Morphogenesis and Odontoblast Differentiation.

    PubMed

    Meng, Tian; Huang, Yanyu; Wang, Suzhen; Zhang, Hua; Dechow, Paul C; Wang, Xiaofang; Qin, Chunlin; Shi, Bing; D'Souza, Rena N; Lu, Yongbo

    2015-12-04

    Twist1 is a basic helix-loop-helix-containing transcription factor that is expressed in the dental mesenchyme during the early stages of tooth development. To better delineate its roles in tooth development, we generated Twist1 conditional knockout embryos (Twist2(Cre) (/+);Twist1(fl/fl)) by breeding Twist1 floxed mice (Twist1(fl/fl)) with Twist2-Cre recombinase knockin mice (Twist2(Cre) (/+)). The Twist2(Cre) (/+);Twist1(fl/fl) embryos formed smaller tooth germs and abnormal cusps during early tooth morphogenesis. Molecular and histological analyses showed that the developing molars of the Twist2(Cre) (/+);Twist1(fl/fl) embryos had reduced cell proliferation and expression of fibroblast growth factors 3, 4, 9, and 10 and FGF receptors 1 and 2 in the dental epithelium and mesenchyme. In addition, 3-week-old renal capsular transplants of embryonic day 18.5 Twist2(Cre) (/+);Twist1(fl/fl) molars showed malformed crowns and cusps with defective crown dentin and enamel. Immunohistochemical analyses revealed that the implanted mutant molars had defects in odontoblast differentiation and delayed ameloblast differentiation. Furthermore, in vitro ChIP assays demonstrated that Twist1 was able to bind to a specific region of the Fgf10 promoter. In conclusion, our findings suggest that Twist1 plays crucial roles in regulating tooth development and that it may exert its functions through the FGF signaling pathway. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  15. Technique: imaging earliest tooth development in 3D using a silver-based tissue contrast agent.

    PubMed

    Raj, Muhammad T; Prusinkiewicz, Martin; Cooper, David M L; George, Belev; Webb, M Adam; Boughner, Julia C

    2014-02-01

    Looking in microscopic detail at the 3D organization of initiating teeth within the embryonic jaw has long-proved technologically challenging because of the radio-translucency of these tiny un-mineralized oral tissues. Yet 3D image data showing changes in the physical relationships among developing tooth and jaw tissues are vital to understand the coordinated morphogenesis of vertebrate teeth and jaws as an animal grows and as species evolve. Here, we present a new synchrotron-based scanning solution to image odontogenesis in 3D and in histological detail using a silver-based contrast agent. We stained fixed, intact wild-type mice aged embryonic (E) day 10 to birth with 1% Protargol-S at 37°C for 12-32 hr. Specimens were scanned at 4-10 µm pixel size at 28 keV, just above the silver K-edge, using micro-computed tomography (µCT) at the Canadian Light Source synchrotron. Synchrotron µCT scans of silver-stained embryos showed even the earliest visible stages of tooth initiation, as well as many other tissue types and structures, in histological detail. Silver stain penetration was optimal for imaging structures in intact embryos E15 and younger. This silver stain method offers a powerful yet straightforward approach to visualize at high-resolution and in 3D the earliest stages of odontogenesis in situ, and demonstrates the important of studying the tooth organ in all three planes of view. Copyright © 2013 Wiley Periodicals, Inc.

  16. The Geochemical Earth Reference Model (GERM)

    SciTech Connect

    Staudigel, H.; Albarede, F.; Shaw, H.; McDonough, B.; White, W.

    1996-12-01

    The Geochemical Earth Reference Model (GERM) initiative is a grass- roots effort with the goal of establishing a community consensus on a chemical characterization of the Earth, its major reservoirs, and the fluxes between them. Long term goal of GERM is a chemical reservoir characterization analogous to the geophysical effort of the Preliminary Reference Earth Model (PREM). Chemical fluxes between reservoirs are included into GERM to illuminate the long-term chemical evolution of the Earth and to characterize the Earth as a dynamic chemical system. In turn, these fluxes control geological processes and influence hydrosphere-atmosphere-climate dynamics. While these long-term goals are clearly the focus of GERM, the process of establishing GERM itself is just as important as its ultimate goal. The GERM initiative is developed in an open community discussion on the World Wide Web (GERM home page is at http://www-ep.es.llnl. gov/germ/germ-home.html) that is mediated by a series of editors with responsibilities for distinct reservoirs and fluxes. Beginning with the original workshop in Lyons (March 1996) GERM is continued to be developed on the Internet, punctuated by workshops and special sessions at professional meetings. It is planned to complete the first model by mid-1997, followed by a call for papers for a February 1998 GERM conference in La Jolla, California.

  17. Disruption of Wnt/β-catenin signaling in odontoblasts and cementoblasts arrests tooth root development in postnatal mouse teeth.

    PubMed

    Zhang, Ran; Yang, Guan; Wu, Ximei; Xie, Jing; Yang, Xiao; Li, Tiejun

    2013-01-01

    Tooth development undergoes a series of complex reciprocal interactions between dental epithelium and the underlying mesenchymal cells. Compared with the study in tooth crown formation, little is known about the molecular mechanism underlying the development of tooth roots. In the present study, we conditionally knock out β-catenin gene (Ctnnb1) within developing odontoblasts and cementoblasts during the development of tooth roots, and observed rootless molars as well as incomplete incisors. Histological analyses revealed intact structure of molar crown and labial side of incisor, however, as for the molar roots and the lingual portion of incisor, the formation of dentin and periodontal tissues were greatly hampered. In situ hybridization experiments using probes of odontoblastic marker genes collagen type I, alpha 1 (Col1a1), osteocalcin (OC) and dentin sialophosphoprotein (Dspp) manifested striking undifferentiation of root odontoblasts in which Ctnnb1 was eliminated. Bromodeoxyuridine (BrdU) labeling and proliferating cell nuclear antigen (PCNA) immunohistochemical experiments also showed retarded proliferation of pre-odontoblasts in mutant mice. However, cell apoptosis was not affected. Additionally, a disrupted formation of cementoblasts, suggested by the absence of transcripts of bone sialoprotein (Bsp) in follicle mesenchyme, was also evident in mutant mice. Our study provides strong in vivo evidence to confirm that Wnt/β-catenin signaling is functionally significant to root odontogenesis and cementogenesis during the tooth root development.

  18. Disruption of Wnt/β-catenin Signaling in Odontoblasts and Cementoblasts Arrests Tooth Root Development in Postnatal Mouse Teeth

    PubMed Central

    Zhang, Ran; Yang, Guan; Wu, Ximei; Xie, Jing; Yang, Xiao; Li, Tiejun

    2013-01-01

    Tooth development undergoes a series of complex reciprocal interactions between dental epithelium and the underlying mesenchymal cells. Compared with the study in tooth crown formation, little is known about the molecular mechanism underlying the development of tooth roots. In the present study, we conditionally knock out β-catenin gene (Ctnnb1) within developing odontoblasts and cementoblasts during the development of tooth roots, and observed rootless molars as well as incomplete incisors. Histological analyses revealed intact structure of molar crown and labial side of incisor, however, as for the molar roots and the lingual portion of incisor, the formation of dentin and periodontal tissues were greatly hampered. In situ hybridization experiments using probes of odontoblastic marker genes collagen type I, alpha 1 (Col1a1), osteocalcin (OC) and dentin sialophosphoprotein (Dspp) manifested striking undifferentiation of root odontoblasts in which Ctnnb1 was eliminated. Bromodeoxyuridine (BrdU) labeling and proliferating cell nuclear antigen (PCNA) immunohistochemical experiments also showed retarded proliferation of pre-odontoblasts in mutant mice. However, cell apoptosis was not affected. Additionally, a disrupted formation of cementoblasts, suggested by the absence of transcripts of bone sialoprotein (Bsp) in follicle mesenchyme, was also evident in mutant mice. Our study provides strong in vivo evidence to confirm that Wnt/β-catenin signaling is functionally significant to root odontogenesis and cementogenesis during the tooth root development. PMID:23494738

  19. Differential spatiotemporal expression of E- and P-cadherin during mouse tooth development.

    PubMed

    Palacios, J; Benito, N; Berraquero, R; Pizarro, A; Cano, A; Gamallo, C

    1995-08-01

    Changes in E- and P-cadherin (E- and P-CD) expression during embryonic mouse first molar development were analyzed by immunohistochemistry. During the induction and morphogenesis stages (bud, cap and early bell stages), E-CD was expressed in the cells of the invaginating epithelial tooth bud and in the cells of the outer enamel epithelium, stellate reticulum and stratum intermedium, suggesting a role for this molecule in the maintenance of enamel organ architecture. On the other hand, P-CD was strongly expressed in the inner enamel epithelium suggesting its participation in the processes of mesenchymal induction. during the cytodifferentiation stage (late bell stage), E-CD was expressed in polarizing preameloblasts, but cadherin expression was restricted to the basal and apical poles of differentiated secretory ameloblasts, where the zonula adherens type of cell-cell junctions is located. The present study demonstrates for the first time the spatiotemporal expression of cadherins during tooth development and suggests differential and specific roles for E-CD and P-CD during the morphogenesis and cytodifferentiation processes of this organ.

  20. Development of In Vivo Tooth EPR for Individual Radiation Dose Estimation and Screening

    PubMed Central

    Williams, Benjamin B.; Dong, Ruhong; Kmiec, Maciej; Burke, Greg; Demidenko, Eugene; Gladstone, David; Nicolalde, Roberto J; Sucheta, Artur; Lesniewski, Piotr; Swartz, Harold M

    2009-01-01

    The development of in vivo EPR has made it feasible to perform tooth dosimetry measurements in situ, greatly expanding the potential for using this approach for immediate screening after radiation exposures. The ability of in vivo tooth dosimetry to provide estimates of absorbed dose has been established through a series of experiments using unirradiated volunteers with specifically irradiated molar teeth placed in situ within gaps in their dentition and in natural canine teeth of patients who have completed courses of radiation therapy for head and neck cancers. Multiple measurements in patients who have received radiation therapy demonstrate the expected heterogeneous dose distributions. Dose response curves have been generated using both populations and, using the current methodology and instrument, the standard error of prediction based on single 4.5 minute measurements is approximately 1.5 Gy for inserted molar teeth and between 2.0 and 2.5 Gy in the more irregularly shaped canine teeth. Averaging of independent measurements can reduce this error significantly to values near 1 Gy. Developments to reduce these errors are underway, focusing on geometric optimization of the resonators, detector positioning techniques, and optimal data averaging approaches. In summary, it seems plausible that the EPR dosimetry techniques will have an important role in retrospective dosimetry for exposures involving large numbers of individuals. PMID:20065702

  1. Limb, tooth, beak: three modes of development and evolutionary innovation of form.

    PubMed

    Linde-Medina, Marta; Newman, Stuart A

    2014-04-01

    The standard model of evolutionary change of form, deriving from Darwin's theory via the Modern Synthesis, assumes a gradualistic reshaping of anatomical structures, with major changes only occurring by many cycles of natural selection for marginal adaptive advantage. This model, with its assertion that a single mechanism underlies both micro- and macroevolutionary change, contains an implicit notion of development which is only applicable in some cases. Here we compare the embryological processes that shape the vertebrate limb bud, the mammalian tooth and the avian beak. The implied notion of development in the standard evolutionary picture is met only in the case of the vertebrate limb, a single-primordium organ with morphostatic shaping, in which cells rearrange in response to signalling centres which are essentially unchanged by cell movement. In the case of the tooth, a single-primordium organ with morphodynamic shaping in which the strengths and relationships between signalling centres is influenced by the cell and tissue movements they induce, and the beak, in which the final form is influenced by the collision and rearrangement of multiple tissue primordia, abrupt appearance of qualitatively different forms (i.e. morphological novelties) can occur with small changes in system parameters induced by a genetic change, or by an environmental factor whose effects can be subsequently canalized genetically. Bringing developmental mechanisms and, specifically, the material properties of tissues as excitable media into the evolutionary picture, demonstrates that gradualistic change for incremental adaptive advantage is only one of the possible modes of morphological evolution.

  2. Orthodontic force accelerates dentine mineralization during tooth development in juvenile rats.

    PubMed

    Kong, Xiangwei; Cao, Meng; Ye, Ruidong; Ding, Yin

    2010-08-01

    Malocclusion, the improper positioning of the teeth and jaws, is among the most important global oral health burdens. People with malocclusion may require orthodontic treatment to correct the problem. Orthodontic treatment is a way of straightening or moving teeth, to improve the appearance of the teeth and how they work. It is generally best carried out in children aged 9 to 12 years, whose teeth are mainly young permanent teeth with incomplete root formation. However, the relationship between orthodontic force and tooth development has not been fully understood. In this study, we sought to investigate the effects of orthodontic force on dentine formation and mineralization during the development of young permanent teeth. Standardized orthodontic tooth movement was performed with the orthodontic appliance in five-week-old rats. To obtain longitudinal assessment of dentine formation, tetracycline was administered on the operation day and 1, 3, 7, 14 or 21 days afterward. We found that the distance between two tetracycline stripes, which indicates the amount of dentine formation during orthodontic treatment, increased with time. Importantly, no significant difference was detected in dentine formation between treated and control rats. In contrast, immunohistochemical analysis showed that the expression of dentin sialoprotein, a marker of odontoblast differentiation and mineral apposition, was significantly elevated in crown and root dentine after orthodontic treatment. In conclusion, orthodontic treatment does not affect the dentine formation of young permanent teeth, but it promotes the activation of odontoblasts and accelerates the dentine mineralization. These results suggest the safety of early orthodontic treatment.

  3. New developed cylindrical TM010 mode EPR cavity for X-band in vivo tooth dosimetry.

    PubMed

    Junwang, Guo; Qingquan, Yuan; Jianbo, Cong; Lei, Ma; Guofu, Dong; Guoshan, Yang; Ke, Wu

    2014-01-01

    EPR tooth in vivo dosimetry is an attractive approach for initial triage after unexpected nuclear events. An X-band cylindrical TM010 mode resonant cavity was developed for in vivo tooth dosimetry and used in EPR applications for the first time. The cavity had a trapezoidal measuring aperture at the exact position of the cavity's cylindrical wall where strong microwave magnetic field H1 concentrated and weak microwave electric field E1 distributed. Theoretical calculations and simulations were used to design and optimize the cavity parameters. The cavity features were evaluated by measuring DPPH sample, intact incisor samples embed in a gum model and the rhesus monkey teeth. The results showed that the cavity worked at designed frequency and had the ability to make EPR spectroscopy in relative high sensitivity. Sufficient modulation amplitude and microwave power could be applied into the aperture. Radiation induced EPR signal could be observed remarkably from 1 Gy irradiated intact incisor within only 30 seconds, which was among the best in scan time and detection limit. The in vivo spectroscopy was also realized by acquiring the radiation induced EPR signal from teeth of rhesus monkey whose teeth was irradiated by dose of 2 Gy. The results suggested that the cavity was sensitive to meet the demand to assess doses of significant level in short time. This cavity provided a very potential option for the development of X-band in vivo dosimetry.

  4. Development of in vivo tooth EPR for individual radiation dose estimation and screening.

    PubMed

    Williams, Benjamin B; Dong, Ruhong; Kmiec, Maciej; Burke, Greg; Demidenko, Eugene; Gladstone, David; Nicolalde, Roberto J; Sucheta, Artur; Lesniewski, Piotr; Swartz, Harold M

    2010-02-01

    The development of in vivo EPR has made it feasible to perform tooth dosimetry measurements in situ, greatly expanding the potential for using this approach for immediate screening after radiation exposures. The ability of in vivo tooth dosimetry to provide estimates of absorbed dose has been established through a series of experiments using unirradiated volunteers with specifically irradiated molar teeth placed in situ within gaps in their dentition and in natural canine teeth of patients who have completed courses of radiation therapy for head and neck cancers. Multiple measurements in patients who have received radiation therapy demonstrate the expected heterogeneous dose distributions. Dose-response curves have been generated using both populations and, using the current methodology and instrument, the standard error of prediction based on single 4.5-min measurements is approximately 1.5 Gy for inserted molar teeth and between 2.0 and 2.5 Gy in the more irregularly shaped canine teeth. Averaging of independent measurements can reduce this error significantly to values near 1 Gy. Developments to reduce these errors are underway, focusing on geometric optimization of the resonators, detector positioning techniques, and optimal data averaging approaches. In summary, it seems plausible that the EPR dosimetry techniques will have an important role in retrospective dosimetry for exposures involving large numbers of individuals.

  5. New Developed Cylindrical TM010 Mode EPR Cavity for X-Band In Vivo Tooth Dosimetry

    PubMed Central

    Junwang, Guo; Qingquan, Yuan; Jianbo, Cong; Lei, Ma; Guofu, Dong; Guoshan, Yang; Ke, Wu

    2014-01-01

    EPR tooth in vivo dosimetry is an attractive approach for initial triage after unexpected nuclear events. An X-band cylindrical TM010 mode resonant cavity was developed for in vivo tooth dosimetry and used in EPR applications for the first time. The cavity had a trapezoidal measuring aperture at the exact position of the cavity’s cylindrical wall where strong microwave magnetic field H1 concentrated and weak microwave electric field E1 distributed. Theoretical calculations and simulations were used to design and optimize the cavity parameters. The cavity features were evaluated by measuring DPPH sample, intact incisor samples embed in a gum model and the rhesus monkey teeth. The results showed that the cavity worked at designed frequency and had the ability to make EPR spectroscopy in relative high sensitivity. Sufficient modulation amplitude and microwave power could be applied into the aperture. Radiation induced EPR signal could be observed remarkably from 1 Gy irradiated intact incisor within only 30 seconds, which was among the best in scan time and detection limit. The in vivo spectroscopy was also realized by acquiring the radiation induced EPR signal from teeth of rhesus monkey whose teeth was irradiated by dose of 2 Gy. The results suggested that the cavity was sensitive to meet the demand to assess doses of significant level in short time. This cavity provided a very potential option for the development of X-band in vivo dosimetry. PMID:25222483

  6. Identification of a germ-line pro-B cell subset that distinguishes the fetal/neonatal from the adult B cell development pathway.

    PubMed

    Lu, Li-Sheng; Tung, James; Baumgarth, Nicole; Herman, Ometa; Gleimer, Michael; Herzenberg, Leonard A; Herzenberg, Leonore A

    2002-03-05

    Studies presented here show that the expression of CD4, MHC class II (Ia,) and B220 cleanly resolves a major and a minor subset within the earliest pro-B cell population (germ-line pro-B) in adult bone marrow (BM). The major subset expresses intermediate B220 and low CD4 levels. The minor subset, which constitutes roughly 20% of the adult germ-line pro-B, expresses very low B220 levels and does not express CD4. Ia is clearly detectable at low levels on the major germ-line pro-B subset, both in wild-type adult mice and in gene-targeted mice (RAG2-/- and microMT), in which B cell development terminates before the pre-B cell stage. A small proportion of cells in the more mature pro-B cell subsets (Hardy Fractions B and C) also express Ia at this level. In contrast, Ia levels on the minor subset are barely above (or equal to) background. Surprisingly, the major germ-line pro-B cell subset found in adults is missing in fetal and neonatal animals. All of the germ-line pro-B in these immature animals express a phenotype (very low B220, no CD4, or Ia) similar to that of the minor pro-B cell subset in adult BM. Because B cell development in fetal/neonatal animals principally results in B-1 cells, these findings demonstrate that the B-1 development pathway does not include the major germ-line pro-B subset found in adult BM and hence identify a very early difference between the B-1 and -2 development pathways.

  7. Different expression patterns of Lin28 and Lin28b in mouse molar development.

    PubMed

    Dong, Ning; Liu, Yan; Zhang, Tiantian; Zhao, Lin; Tian, Jiangang; Ruan, Jianping

    2017-10-01

    The RNA-binding proteins Lin28 and Lin28b are expressed in many developing tissues and are involved in the biosynthesis of the microRNA let-7 family and embryogenesis processes. However, their roles in mammalian tooth development remain ill-defined. The spatiotemporal expressions of Lin28 and Lin28b during mouse molar odontogenesis from day E11.5 to P21 were examined through immunohistochemistry and western blot analysis. Both Lin28 and Lin28b were initially expressed in dental epithelium, but the expression patterns varied thereafter. Lin28 was expressed in tooth germ from early embryonic stages and was consistently expressed in the ameloblasts and odontoblasts throughout all stages of tooth development. However, positive staining of Lin28b gradually faded out with tooth germ development, before finally disappearing in tooth organ cells after birth. These results indicate that Lin28 was spatiotemporally expressed in tooth germ throughout tooth development progression and may play an active role in ameloblast and odontoblast differentiation, as well as matrix secretion and the mineralization of enamel and dentin. Its paralogue Lin28b may have a distinct function in tooth germ formation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Defining properties of neural crest-derived progenitor cells from the apex of human developing tooth.

    PubMed

    Degistirici, Ozer; Jaquiery, Claude; Schönebeck, Bodo; Siemonsmeier, Jürgen; Götz, Werner; Martin, Ivan; Thie, Michael

    2008-02-01

    The connective tissue of the human tooth arises from cells that are derived from the cranial neural crest and, thus, are termed as "ectomesenchymal cells." Here, cells being located in a pad-like tissue adjacent to the apex of the developing tooth, which we designated the third molar pad, were separated by the microexplant technique. When outgrowing from the explant, dental neural crest-derived progenitor cells (dNC-PCs) adhered to plastic, proliferated steadily, and displayed a fibroblast-like morphology. At the mRNA level, dNC-PCs expressed neural crest marker genes like Sox9, Snail1, Snail2, Twist1, Msx2, and Dlx6. Cytofluorometric analysis indicated that cells were positive for CD49d (alpha4 integrin), CD56 (NCAM), and PDGFRalpha, while negative for CD31, CD34, CD45, and STRO-1. dNC-PCs could be differentiated into neurogenic, chondrogenic, and osteogenic lineages and were shown to produce bone matrix in athymic mice. These results demonstrate that human third molar pad possesses neural crest-derived cells that represent multipotent stem/progenitor cells. As a rather large amount of dNC-PCs could be obtained from each single third molar, cells may be used to regenerate a wide range of tissues within the craniofacial region of humans.

  9. Accuracy of developing tooth length as an estimate of age in human skeletal remains: the deciduous dentition.

    PubMed

    Cardoso, Hugo F V

    2007-10-02

    Dental age assessments are widely used to estimate age of immature skeletal remains. Most methods have relied on fractional stages of tooth emergence and formation, particularly of the permanent dentition, for predicting the age of infants and very young children. In this study, the accuracy of regression equations of developing deciduous tooth length for age estimation (Liversidge et al.) is tested on a sample of 30 Portuguese subadult skeletons of known age at death. Overall the method shows high accuracy and the average difference between estimated and chronological age is between 0.20 and -0.14 years when using single teeth, and 0.06 years, when using all available teeth. However, there is a tendency for the deciduous molars to provide overestimates of chronological age. Results show that age estimates can be obtained within +/-0.10 years with a 95% confidence interval when several teeth are used. Overall between-tooth agreement in age estimates decreases with increasing age but there is less variability of estimates with more teeth contributing to overall mean age. One seemingly limitation of this method may be the fact that it was developed by combining the maxillary and mandibular teeth. The other is related to the accuracy with which radiographic tooth length can be used as a valid surrogate for actual tooth length. Nevertheless, the advantages of this metric method surpass the limitations of chronologies based on stages of dental development.

  10. Development of the adverse outcome pathway "alkylation of DNA in male premeiotic germ cells leading to heritable mutations" using the OECD's users' handbook supplement.

    PubMed

    Yauk, Carole L; Lambert, Iain B; Meek, M E Bette; Douglas, George R; Marchetti, Francesco

    2015-12-01

    The Organisation for Economic Cooperation and Development's (OECD) Adverse Outcome Pathway (AOP) programme aims to develop a knowledgebase of all known pathways of toxicity that lead to adverse effects in humans and ecosystems. A Users' Handbook was recently released to provide supplementary guidance on AOP development. This article describes one AOP-alkylation of DNA in male premeiotic germ cells leading to heritable mutations. This outcome is an important regulatory endpoint. The AOP describes the biological plausibility and empirical evidence supporting that compounds capable of alkylating DNA cause germ cell mutations and subsequent mutations in the offspring of exposed males. Alkyl adducts are subject to DNA repair; however, at high doses the repair machinery becomes saturated. Lack of repair leads to replication of alkylated DNA and ensuing mutations in male premeiotic germ cells. Mutations that do not impair spermatogenesis persist and eventually are present in mature sperm. Thus, the mutations are transmitted to the offspring. Although there are some gaps in empirical support and evidence for essentiality of the key events for certain aspects of this AOP, the overall AOP is generally accepted as dogma and applies broadly to any species that produces sperm. The AOP was developed and used in an iterative process to test and refine the Users' Handbook, and is one of the first publicly available AOPs. It is our hope that this AOP will be leveraged to develop other AOPs in this field to advance method development, computational models to predict germ cell effects, and integrated testing strategies.

  11. SKAP, an outer kinetochore protein, is required for mouse germ cell development

    PubMed Central

    Grey, Corinne; Espeut, Julien; Ametsitsi, Rachel; Kumar, Rajeev; Luksza, Malgorzata; Brun, Christine; Verlhac, Marie-Hélene; Suja, José Angél; de Massy, Bernard

    2016-01-01

    In sexually reproducing organisms, accurate gametogenesis is crucial for the transmission of genetic material from one generation to the next. This requires the faithful segregation of chromosomes during mitotic and meiotic divisions. One of the main players in this process is the kinetochore, a large multi-protein complex that forms at the interface of centromeres and microtubules. Here, we analyzed the expression profile and function of small kinetochore-associated protein (SKAP) in the mouse. We found that two distinct SKAP isoforms are specifically expressed in the germline: a smaller isoform, which is detected in spermatogonia and spermatocytes and localized in the outer mitotic and meiotic kinetochores from metaphase to telophase, and a larger isoform, which is expressed in the cytoplasm of elongating spermatids. We generated SKAP-deficient mice and found that testis size and sperm production were severely reduced in mutant males. This phenotype was partially caused by defects during spermatogonia proliferation before entry into meiosis. We conclude that mouse SKAP, while being dispensable for somatic cell divisions, has an important role in the successful outcome of male gametogenesis. In germ cells, analogous to what has been suggested in studies using immortalized cells, SKAP most likely stabilizes the interaction between kinetochores and microtubules, where it might be needed as an extra safeguard to ensure the correct segregation of mitotic and meiotic chromosomes. PMID:26667018

  12. A set of genes critical to development is epigenetically poised in mouse germ cells from fetal stages through completion of meiosis.

    PubMed

    Lesch, Bluma J; Dokshin, Gregoriy A; Young, Richard A; McCarrey, John R; Page, David C

    2013-10-01

    In multicellular organisms, germ cells carry the hereditary material from one generation to the next. Developing germ cells are unipotent gamete precursors, and mature gametes are highly differentiated, specialized cells. However, upon gamete union at fertilization, their genomes drive a totipotent program, giving rise to a complete embryo as well as extraembryonic tissues. The biochemical basis for the ability to transition from differentiated cell to totipotent zygote is unknown. Here we report that a set of developmentally critical genes is maintained in an epigenetically poised (bivalent) state from embryonic stages through the end of meiosis. We performed ChIP-seq and RNA-seq analysis on flow-sorted male and female germ cells during embryogenesis at three time points surrounding sexual differentiation and female meiotic initiation, and then extended our analysis to meiotic and postmeiotic male germ cells. We identified a set of genes that is highly enriched for regulators of differentiation and retains a poised state (high H3K4me3, high H3K27me3, and lack of expression) across sexes and across developmental stages, including in haploid postmeiotic cells. The existence of such a state in embryonic stem cells has been well described. We now demonstrate that a subset of genes is maintained in a poised state in the germ line from the initiation of sexual differentiation during fetal development and into postmeiotic stages. We propose that the epigenetically poised condition of these developmental genes is a fundamental property of the mammalian germ-line nucleus, allowing differentiated gametes to unleash a totipotent program following fertilization.

  13. A set of genes critical to development is epigenetically poised in mouse germ cells from fetal stages through completion of meiosis

    PubMed Central

    Lesch, Bluma J.; Dokshin, Gregoriy A.; Young, Richard A.; McCarrey, John R.; Page, David C.

    2013-01-01

    In multicellular organisms, germ cells carry the hereditary material from one generation to the next. Developing germ cells are unipotent gamete precursors, and mature gametes are highly differentiated, specialized cells. However, upon gamete union at fertilization, their genomes drive a totipotent program, giving rise to a complete embryo as well as extraembryonic tissues. The biochemical basis for the ability to transition from differentiated cell to totipotent zygote is unknown. Here we report that a set of developmentally critical genes is maintained in an epigenetically poised (bivalent) state from embryonic stages through the end of meiosis. We performed ChIP-seq and RNA-seq analysis on flow-sorted male and female germ cells during embryogenesis at three time points surrounding sexual differentiation and female meiotic initiation, and then extended our analysis to meiotic and postmeiotic male germ cells. We identified a set of genes that is highly enriched for regulators of differentiation and retains a poised state (high H3K4me3, high H3K27me3, and lack of expression) across sexes and across developmental stages, including in haploid postmeiotic cells. The existence of such a state in embryonic stem cells has been well described. We now demonstrate that a subset of genes is maintained in a poised state in the germ line from the initiation of sexual differentiation during fetal development and into postmeiotic stages. We propose that the epigenetically poised condition of these developmental genes is a fundamental property of the mammalian germ-line nucleus, allowing differentiated gametes to unleash a totipotent program following fertilization. PMID:24043772

  14. Persistent Requirement and Alteration of the Key Targets of PRDM1 During Primordial Germ Cell Development in Mice.

    PubMed

    Yamashiro, Chika; Hirota, Takayuki; Kurimoto, Kazuki; Nakamura, Tomonori; Yabuta, Yukihiro; Nagaoka, So I; Ohta, Hiroshi; Yamamoto, Takuya; Saitou, Mitinori

    2016-01-01

    Primordial germ cells (PGCs) are the foundation of totipotency and vital for reproduction and heredity. PGCs in mice arise from the epiblast around Embryonic Day (E) 7.0, migrate through the hindgut endoderm, and colonize and proliferate in the embryonic gonads until around E13.5 prior to their differentiation either into prospermatogonia or oogonia. PRDM1, a transcriptional repressor, plays an essential role in PGC specification that includes robustly repressing a somatic mesodermal program. Using an inducible conditional knockout system, we show here that PRDM1 is critically required throughout PGC development. When Prdm1 was deleted in migrating PGCs at E9.5 or E10.5, or in male gonadal PGCs at E11.5, PGCs were eliminated by apoptosis from around E10.5, E11.5, or E13.5, respectively. When Prdm1 was deleted in female gonadal PGCs at E11.5, PGCs progressed into the first meiotic prophase in an apparently normal fashion, but the oogonia exhibited an aberrant pachytene phenotype, undergoing abrupt apoptosis from around E16.5. The escape of a fraction of PGCs (∼10%) from the Prdm1 deletion was sufficient to recover fairly normal germ cell pools, both in male and female adults. The key targets of PRDM1 in migrating and/or gonadal PGCs, including genes for development, apoptosis, and prospermatogonial differentiation, showed only a modest overlap with those upon PGC specification, and were enriched with histone H3 lysine 27 trimethylation (H3K27me3). Our findings provide critical insight into the mechanism for maintaining the transcriptional integrity of PGCs. © 2016 by the Society for the Study of Reproduction, Inc.

  15. Radiographic study of delayed tooth development in patients with dental agenesis.

    PubMed

    Ruiz-Mealin, Erika V; Parekh, Susan; Jones, Steven P; Moles, David R; Gill, Daljit S

    2012-03-01

    The aims of this study were to compare the radiographic development of permanent teeth in a group of children affected by dental agenesis with an unaffected control group and to determine the effects of confounding factors including the severity of the dental agenesis, age, sex, ethnicity, and the number of stages used to estimate dental age. A single-center retrospective cross-sectional study of dental panoramic tomographs was undertaken between July 2007 and April 2008 in a postgraduate teaching school. A total of 139 patients (aged 9-18 years) were recruited from the orthodontic clinic on the basis of predetermined inclusion and exclusion criteria to either a dental agenesis group or a control group. Dental panoramic tomograms were assessed, and the stages of development of the permanent teeth in the left maxillary and left mandibular regions were scored by using the 12 stages of Haavikko and the 8 stages of Demirjian and Goldstein. For each tooth scored, the mean dental age and standard error were determined by using the dental age assessment method, and an estimated dental age for each subject was derived by using the weighted average method. A statistically significant delay in dental age was found in the patients with dental agenesis compared with the control group. The dental age assessment method of Haavikko showed a delay of 1.20 years (SD, 1.74), and the method of Demirjian and Goldstein showed a delay of 1.64 years (SD, 1.75). It was also observed that older patients with dental agenesis had greater delays in tooth formation (P <0.001). With the Haavikko method, for every year of chronologic age, the delay in dental age increased by 0.53 year; with the Demirjian and Goldstein method, the delay increased by 0.48 year. A significant association was seen between the severity of dental agenesis and the delay in dental age (P <0.01). With both methods, for each additional developmentally absent tooth, the dental age was delayed by 0.13 year (lower confidence

  16. Exceptionally prolonged tooth formation in elasmosaurid plesiosaurians

    PubMed Central

    Kear, Benjamin P.; Larsson, Dennis; Lindgren, Johan; Kundrát, Martin

    2017-01-01

    Elasmosaurid plesiosaurians were globally prolific marine reptiles that dominated the Mesozoic seas for over 70 million years. Their iconic body-plan incorporated an exceedingly long neck and small skull equipped with prominent intermeshing ‘fangs’. How this bizarre dental apparatus was employed in feeding is uncertain, but fossilized gut contents indicate a diverse diet of small pelagic vertebrates, cephalopods and epifaunal benthos. Here we report the first plesiosaurian tooth formation rates as a mechanism for servicing the functional dentition. Multiple dentine thin sections were taken through isolated elasmosaurid teeth from the Upper Cretaceous of Sweden. These specimens revealed an average of 950 daily incremental lines of von Ebner, and infer a remarkably protracted tooth formation cycle of about 2–3 years–other polyphyodont amniotes normally take ~1–2 years to form their teeth. Such delayed odontogenesis might reflect differences in crown length and function within an originally uneven tooth array. Indeed, slower replacement periodicity has been found to distinguish larger caniniform teeth in macrophagous pliosaurid plesiosaurians. However, the archetypal sauropterygian dental replacement system likely also imposed constraints via segregation of the developing tooth germs within discrete bony crypts; these partly resorbed to allow maturation of the replacement teeth within the primary alveoli after displacement of the functional crowns. Prolonged dental formation has otherwise been linked to tooth robustness and adaption for vigorous food processing. Conversely, elasmosaurids possessed narrow crowns with an elongate profile that denotes structural fragility. Their apparent predilection for easily subdued prey could thus have minimized this potential for damage, and was perhaps coupled with selective feeding strategies that ecologically optimized elasmosaurids towards more delicate middle trophic level aquatic predation. PMID:28241059

  17. Lef1 expression is activated by BMP-4 and regulates inductive tissue interactions in tooth and hair development.

    PubMed

    Kratochwil, K; Dull, M; Farinas, I; Galceran, J; Grosschedl, R

    1996-06-01

    Targeted inactivation of the murine gene encoding the transcription factor LEF-1 abrogates the formation of organs that depend on epithelial-mesenchymal tissue interactions. In this study we have recombined epithelial and mesenchymal tissues from normal and LEF-1-deficient embryos at different stages of development to define the LEF-1-dependent steps in tooth and whisker organogenesis. At the initiation of organ development, formation of the epithelial primordium of the whisker but not tooth is dependent on mesenchymal Lef1 gene expression. Subsequent formation of a whisker and tooth mesenchymal papilla and completion of organogenesis require transient expression of Lef1 in the epithelium. These experiments indicate that the effect of Lef1 expression is transmitted from one tissue to the other. In addition, the finding that the expression of Lef1 can be activated by bone morphogenetic protein 4 (BMP-4) suggests a regulatory role of this transcription factor in BMP-mediated inductive tissue interactions.

  18. Integration of tooth morphogenesis and innervation by local tissue interactions, signaling networks, and semaphorin 3A

    PubMed Central

    Luukko, Keijo; Kettunen, Päivi

    2016-01-01

    ABSTRACT The tooth, like many other organs, develops from both epithelial and mesenchymal tissues, and has proven to be a valuable tool with which to investigate organ formation and peripheral innervation. Tooth formation is regulated by local epithelial-mesenchymal tissue interactions, and is closely integrated with stereotypic dental nerve navigation and patterning. Recent analyses of the function and regulation of semaphorin 3A (SEMA3A) have shed light on the regulatory mechanisms that coordinate organogenesis and innervation at the tissue and molecular levels. In the tooth, SEM3A acts as a developmentally regulated secretory chemo-repellent, that controls tooth innervation during embryonic and postnatal development. The tooth germ governs its own innervation by a combination of local tissue interactions and SEMA3A expression. SEMA3A signaling, in turn, is controlled by a number of conserved signaling effectors, including TGF-β superfamily members, FGF, and WNT; all function in embryo and organ development, and are essential for tooth histo-morphogenesis. Thus, SEMA3A driven axon guidance is integrated into key odontogenic signaling networks, establishing this protein as a critical molecular tether between 2 distinct developmental processes (morphogenesis and sensory innervation), both of which are required to obtain a functional tooth. PMID:27715429

  19. Tooth Disorders

    MedlinePlus

    ... include eating, speaking and even smiling. But tooth disorders are nothing to smile about. They include problems ... your teeth. Fortunately, you can prevent many tooth disorders by taking care of your teeth and keeping ...

  20. Tooth anatomy

    MedlinePlus

    ... page: //medlineplus.gov/ency/article/002214.htm Tooth anatomy To use the sharing features on this page, ... upper jawbone is called the maxilla. Images Tooth anatomy References Lingen MW. Head and neck. In: Kumar ...

  1. Method development and validation for isoflavones in soy germ pharmaceutical capsules using micellar electrokinetic chromatography.

    PubMed

    Micke, Gustavo Amadeu; Fujiya, Neide Mitsue; Tonin, Fernando Gustavo; de Oliveira Costa, Ana Carolina; Tavares, Marina Franco Maggi

    2006-08-28

    The separation of six soy isoflavones (Glycitein, Daidzein, Genistein, Daidzin, Glycitin and Genistin) was approached by a 3(2) factorial design studying MEKC electrolyte components at the following levels: methanol (MeOH; 0-10%) and sodium dodecylsulfate (SDS; 20-70 mmol L(-1)); sodium tetraborate buffer (STB) concentration was kept constant at 10 mmol L(-1). Nine experiments were performed and the apparent mobility of each isoflavone was computed as a function of the electrolyte composition. A novel response function (RF) was formulated based on the production of the mobility differences, mobility of the first and last eluting peaks and the electrolyte conductance. The inspection of the response surface indicated an optimum electrolyte composition as 10 mmol L(-1) STB (pH 9.3) containing 40 mmol L(-1) SDS and 1% MeOH promoting baseline separation of all isoflavones in less than 7.5 min. The proposed method was applied to the determination of total isoflavones in soy germ capsules from four different pharmaceutical laboratories. A 2h extraction procedure with 80% (v/v) MeOH under vortexing at room temperature was employed. Peak assignment of unknown isoflavones in certain samples was assisted by hydrolysis procedures, migration behavior and UV spectra comparison. Three malonyl isoflavone derivatives were tentatively assigned. A few figures of merit for the proposed method include: repeatability (n=6) better than 0.30% CV (migration time) and 1.7% CV (peak area); intermediate precision (n=18) better than 6.2% CV (concentration); recoveries at two concentration levels, 20 and 50 microg mL(-1), varied from 99.1 to 103.6%. Furthermore, the proposed method exhibited linearity in the concentration range of 1.6-50 microg mL(-1) (r(2)>0.9999) with LOQ varying from 0.67 to 1.2 microg mL(-1). The capsules purity varied from 93.3 to 97.6%.

  2. Development of a risk stratification system to guide treatment for female germ cell tumors.

    PubMed

    Meisel, Jane L; Woo, Kaitlin M; Sudarsan, Nora; Eng, Jana; Patil, Sujata; Jacobsen, Erin P; Murali, Rajmohan; Gardner, Ginger J; Bosl, George J; Aghajanian, Carol; Feldman, Darren R

    2015-09-01

    Due to their rarity, little is known about prognostic factors in female germ cell tumors (GCTs) or outcomes following systemic therapy. Management is largely based on studies of male GCT and epithelial ovarian cancer. Chart review was performed for all females with GCT seen at Memorial Sloan Kettering Cancer Center (MSKCC) from 1990 to 2012. Patients receiving chemotherapy were stratified using a modification of the male IGCCCG risk system, and the classifier was correlated with outcome. Of 93 patients, 92 (99%) underwent primary surgery and 85 (92%) received chemotherapy. Modified IGCCCG classification was significantly associated with progression-free survival (PFS) and overall survival (OS), both when applied preoperatively and pre-chemotherapy (p<0.001 for all four analyses). Progression after initial chemotherapy (n=29) was detected by imaging in 14 (48%) patients, by serum tumor markers in 6 (21%) patients, and by multiple methods in the rest. Seven (29%) of 24 patients treated with salvage chemotherapy achieved long-term PFS, including 4/6 who received high-dose chemotherapy (HDCT) as initial salvage versus 3/16 treated with other initial salvage regimens. The estimated 3-year OS rate was 84% (95% CI, 76-92%), with a trend favoring dysgerminoma over non-dysgerminoma histologies (p=0.12). Modified IGCCCG classification was prognostic for female GCT patients in this cohort and identified a poor-risk group who may benefit from more intensive first-line chemotherapy. Both imaging and tumor marker evaluation were important in identifying relapses after first-line chemotherapy. The majority of long-term remissions with salvage therapy were achieved with initial salvage HDCT. Copyright © 2015 Elsevier Inc. All rights reserved.

  3. Immunolocalization of fibroblast growth factor-2 (FGF-2) in the developing root and supporting structures of the murine tooth.

    PubMed

    Madan, A K; Kramer, Beverley

    2005-03-01

    Epithelio-mesenchymal interactions are active during the development of the root of the tooth and are regulated by a variety of growth factors, such as fibroblast growth factors. FGF-2, 3, 4, and 8 have all been shown to play a role in the development of the crown of the tooth, but less is known about the factors that govern root formation, particularly FGF-2. The aim of this study was thus to elucidate the spatial and temporal expression of FGF-2 in the root of the developing tooth, as this growth factor is believed to be a mediator of epithelio-mesenchymal interactions. Parasagittal sections of the maxillary and mandibular arches of post-natal mice were utilized and the roots of the molar teeth were studied. Immunocytochemistry utilizing an antibody to FGF-2 was performed on sections of teeth at various stages of development. Intense immunostaining for FGF-2 was observed in differentiating odontoblasts at the apical end of the tooth and in the furcation zone of the developing root at all the stages examined. FGF-2 localization was also observed in cementoblasts on post-natal days 16, 20 and 24. The pattern of localization of FGF-2 in the developing root suggests that this growth factor may participate in the signaling network associated with root development.

  4. Transcription factor Sp3 is essential for post-natal survival and late tooth development.

    PubMed

    Bouwman, P; Göllner, H; Elsässer, H P; Eckhoff, G; Karis, A; Grosveld, F; Philipsen, S; Suske, G

    2000-02-15

    Sp3 is a ubiquitously expressed transcription factor closely related to Sp1 (specificity protein 1). We have disrupted the mouse Sp3 gene by homologous recombination. Sp3-deficient embryos are growth retarded and invariably die at birth of respiratory failure. The cause for the observed breathing defect remains obscure since only minor morphological alterations were observed in the lung, and surfactant protein expression is indistinguishable from that in wild-type mice. Histological examinations of individual organs in Sp3(-/-) mice show a pronounced defect in late tooth formation. In Sp3 null mice, the dentin/enamel layer of the developing teeth is impaired due to the lack of ameloblast-specific gene products. Comparison of the Sp1 and Sp3 knockout phenotype shows that Sp1 and Sp3 have distinct functions in vivo, but also suggests a degree of functional redundancy.

  5. Role of Osterix and MicroRNAs in Bone Formation and Tooth Development

    PubMed Central

    Wang, Chuan; Liao, Haiqing; Cao, Zhengguo

    2016-01-01

    Osterix (Osx) is an osteoblast-specific transcription factor that is essential for bone formation. MicroRNAs (miRNAs) are ~22-nucleotide-long noncoding RNAs that play important regulatory roles in animals and plants by targeting mRNAs for cleavage or translational repression. They can also control osteoblast-mediated bone formation and osteoclast-related bone remodeling. The vital roles of Osx and miRNAs during bone formation have been well studied, but very few studies have discussed their co-functions and the relationships between them. In this review, we outline the significant functions of Osx and miRNAs on certain cell types during osteogenesis and illustrate their roles during tooth development. More importantly, we discuss the relationship between Osx and miRNAs, which we believe could lead to a new treatment for skeletal and periodontal diseases. PMID:27543160

  6. Development of a composite resin disclosing agent based on the understanding of tooth staining mechanisms.

    PubMed

    Abdallah, Mohamed-Nur; Light, Nathan; Amin, Wala M; Retrouvey, Jean-Marc; Cerruti, Marta; Tamimi, Faleh

    2014-06-01

    To characterize the surface composition of dental enamel and composite resin, assess the ability of dyes with different affinities to stain these surfaces, and use this information to develop a disclosing agent that stains composite resin more than dental enamel. One hundred and ten sound extracted teeth were collected and 60 discs of composite resin, 9 mm diameter and 3 mm thick, were prepared. X-ray photoelectron spectroscopy (XPS) was employed to determine the elemental composition on the different surfaces. A tooth shade spectrophotometer was used to assess the change in shade after staining the surfaces with different dyes. XPS analysis revealed that surfaces of both outer dental enamel and composite resin contained relatively high amounts of carbon, specifically hydrocarbons. Both dental enamel and composite surfaces were stainable with the hydrophobic dye (p<0.05); however, the composite resin was stained more than the dental enamel (p<0.05). The hydrophobic surface of dental enamel and composite resin might explain their high affinity to be stained by food and beverages containing hydrophobic molecules. The composite resin is more stainable by hydrophobic dyes than dental enamel. We used this information to develop an agent for disclosing composite resins that could be used to visualize composite resins that need to be removed. Removal of composite resin can be problematic, time consuming and stressful to the dental practitioner. A composite disclosing agent would help the dental practitioner identify the composite resin and facilitate its removal without damaging the adjacent healthy tooth tissues. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Varanoid Tooth Eruption and Implantation Modes in a Late Cretaceous Mosasaur

    PubMed Central

    Liu, Min; Reed, David A.; Cecchini, Giancarlo M.; Lu, Xuanyu; Ganjawalla, Karan; Gonzales, Carol S.; Monahan, Richard; Luan, Xianghong

    2016-01-01

    Erupting teeth are some of the oldest witnesses of developmental processes in the vertebrate fossil record and provide an important resource for vertebrate cladistics. Here, we have examined a mosasaur jaw fragment from central Texas using ultrathin ground section histology and 3D tomographic imaging to assess features critical for the cladistic placement of mosasaurs among varanoids vs. snakes: (i) the orientation of replacement teeth compared to the major tooth axis, (ii) the occurrence of resorption pits, and (iii) the mode of tooth implantation/attachment to the tooth bearing element (TBE). The replacement tooth studied here developed in an inclined position slightly distal of the deciduous parent tooth, similar to another varanoid squamate, the Gila monster Heloderma suspectum. Ground sections and tomographs also demonstrated that the replacement tooth attachment apparatus was entirely intact and that there was no evidence of mechanical deformation. Sections and tomographs further illustrated that the replacement tooth was located within a bony crypt and the inclination of the crypt matched the inclination of the replacement tooth. These preparations also revealed the presence of a resorption pit within the boundaries of the deciduous tooth that surrounded the developing replacement tooth. This finding suggests that developing mosasaur teeth developed within the walls of resorption pits similar to varanoid tooth germs and unlike developing snake teeth which are surrounded by fibrous connective tissue integuments. Finally, mosasaurs featured pseudo-thecodont tooth implantation with teeth anchored within a socket of mineralized tissue by means of a mineralized periodontal ligament. Together, these data indicate that the moderate inclination of the erupting mosasaur tooth studied here is neither a result of postmortem displacement nor a character representative of snakes, but rather a shared character between Mosasaurs and other varanoids such as Heloderma. In

  8. Varanoid Tooth Eruption and Implantation Modes in a Late Cretaceous Mosasaur.

    PubMed

    Liu, Min; Reed, David A; Cecchini, Giancarlo M; Lu, Xuanyu; Ganjawalla, Karan; Gonzales, Carol S; Monahan, Richard; Luan, Xianghong; Diekwisch, Thomas G H

    2016-01-01

    Erupting teeth are some of the oldest witnesses of developmental processes in the vertebrate fossil record and provide an important resource for vertebrate cladistics. Here, we have examined a mosasaur jaw fragment from central Texas using ultrathin ground section histology and 3D tomographic imaging to assess features critical for the cladistic placement of mosasaurs among varanoids vs. snakes: (i) the orientation of replacement teeth compared to the major tooth axis, (ii) the occurrence of resorption pits, and (iii) the mode of tooth implantation/attachment to the tooth bearing element (TBE). The replacement tooth studied here developed in an inclined position slightly distal of the deciduous parent tooth, similar to another varanoid squamate, the Gila monster Heloderma suspectum. Ground sections and tomographs also demonstrated that the replacement tooth attachment apparatus was entirely intact and that there was no evidence of mechanical deformation. Sections and tomographs further illustrated that the replacement tooth was located within a bony crypt and the inclination of the crypt matched the inclination of the replacement tooth. These preparations also revealed the presence of a resorption pit within the boundaries of the deciduous tooth that surrounded the developing replacement tooth. This finding suggests that developing mosasaur teeth developed within the walls of resorption pits similar to varanoid tooth germs and unlike developing snake teeth which are surrounded by fibrous connective tissue integuments. Finally, mosasaurs featured pseudo-thecodont tooth implantation with teeth anchored within a socket of mineralized tissue by means of a mineralized periodontal ligament. Together, these data indicate that the moderate inclination of the erupting mosasaur tooth studied here is neither a result of postmortem displacement nor a character representative of snakes, but rather a shared character between Mosasaurs and other varanoids such as Heloderma. In

  9. The effects of periradicular inflamation and infection on a primary tooth and permanent successor.

    PubMed

    Cordeiro, Mabel Mariela Rodriguez; Rocha, Maria Jose de Carvalho

    2005-01-01

    Primary teeth and the permanent successors must be understood as interdependent units, where each one of them interacts with and depends on each other. Pulpal inflammation/infection of a primary tooth and the spread of this condition over the periradicular tissues can lead to alterations in the dental germ of the permanent successor and to the surrounding structures if no therapy is done, i.e. endodontics or extraction. This work will present cases of permanent teeth that showed alteration in eruption and / or in development, as a consequence of inflammation / infection of the preceding primary teeth, such as: hypoplasia, morphological alteration on the dental crown or total arrest of. radicular formation. The teeth analysed in this study belong to patients who attended the Universidade Federal de Santa Catarina Children's Dentistry Clinic. The earlier these lesions are diagnosed, the less were the destructive effects and the consequences on the primary tooth/permanent germ unit.

  10. The role of APCDD1 in epithelial rearrangement in tooth morphogenesis.

    PubMed

    Neupane, Sanjiv; Sohn, Wern-Joo; Gwon, Gi-Jeong; Kim, Ki-Rim; Lee, Sanggyu; An, Chang-Hyeon; Suh, Jo-Young; Shin, Hong-In; Yamamoto, Hitoshi; Cho, Sung-Won; Lee, Youngkyun; Kim, Jae-Young

    2015-10-01

    Adenomatosis polyposis coli downregulated 1 (APCDD1), a negative regulator of Wnt signaling, was examined to understand detailed mechanisms underlying Wnt signaling tooth development. In situ hybridization showed that Apcdd1 was expressed in the condensed mesenchyme at the bud stage, and in the inner enamel epithelium (IEE), including enamel knot (EK) at the cap stage. In vitro organ cultivation by using Apcdd1 antisense oligodeoxynucleotides was performed at E13.5 for 2 days to define the developmental functions of APCDD1 during tooth development. Analysis of histogenesis and cellular events such as cell adhesion, proliferation, apoptosis and epithelial rearrangement after Apcdd1 knockdown showed altered morphogenesis of the tooth germ with decreased cell proliferation and altered localization of cell adhesion molecules. Actin filament staining and 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (DiI) labeling of IEE cells showed that Apcdd1 knockdown enhanced epithelial rearrangement in the IEE and EK. To understand the precise signaling regulations of Apcdd1, we evaluated the altered expression patterns of signaling molecules, related with Wnt and enamel knot signalings using RT-qPCR. Tooth germs at cap stage were transplanted into the kidney capsules and were allowed to develop into calcified teeth for 3 weeks. Apcdd1 knockdown increased the number of ectopic cusps on the mesial side of the tooth. Our results suggested that APCDD1 modulates the gene expression of Wnt- and EK-related signaling molecules at the cap stage of tooth development, and is involved in tooth cusp patterning by modulating the epithelial rearrangement in the IEE.

  11. Bone morphogenetic protein-2 gene controls tooth root development in coordination with formation of the periodontium

    PubMed Central

    Rakian, Audrey; Yang, Wu-Chen; Gluhak-Heinrich, Jelica; Cui, Yong; Harris, Marie A; Villarreal, Demitri; Feng, Jerry Q; MacDougall, Mary; Harris, Stephen E

    2013-01-01

    Formation of the periodontium begins following onset of tooth-root formation in a coordinated manner after birth. Dental follicle progenitor cells are thought to form the cementum, alveolar bone and Sharpey's fibers of the periodontal ligament (PDL). However, little is known about the regulatory morphogens that control differentiation and function of these progenitor cells, as well as the progenitor cells involved in crown and root formation. We investigated the role of bone morphogenetic protein-2 (Bmp2) in these processes by the conditional removal of the Bmp2 gene using the Sp7-Cre-EGFP mouse model. Sp7-Cre-EGFP first becomes active at E18 in the first molar, with robust Cre activity at postnatal day 0 (P0), followed by Cre activity in the second molar, which occurs after P0. There is robust Cre activity in the periodontium and third molars by 2 weeks of age. When the Bmp2 gene is removed from Sp7+ (Osterix+) cells, major defects are noted in root, cellular cementum and periodontium formation. First, there are major cell autonomous defects in root-odontoblast terminal differentiation. Second, there are major alterations in formation of the PDLs and cellular cementum, correlated with decreased nuclear factor IC (Nfic), periostin and α-SMA+ cells. Third, there is a failure to produce vascular endothelial growth factor A (VEGF-A) in the periodontium and the pulp leading to decreased formation of the microvascular and associated candidate stem cells in the Bmp2-cKOSp7-Cre-EGFP. Fourth, ameloblast function and enamel formation are indirectly altered in the Bmp2-cKOSp7-Cre-EGFP. These data demonstrate that the Bmp2 gene has complex roles in postnatal tooth development and periodontium formation. PMID:23807640

  12. [Tooth-pick? Picking the Right Tooth].

    PubMed

    Apicella, Lysann; Cassis, Paola Rodoni; Balestra, Brenno

    2016-01-20

    We report about an 80-year-old patient, who underwent the extraction of an upper molar tooth because of facial pain. In the course of time the patient developed a maxillary sinusitis in presence of an ectopic tooth. Given that the patient got fever, neck pain and -stiffness, a purulent meningitis was first suspected. The liquor analysis was normal and the CT-scan showed a calcification around the dens axis. We finally diagnosed a “Crowned Dens”-syndrome.

  13. Wnt signaling during tooth replacement in zebrafish (Danio rerio): pitfalls and perspectives

    PubMed Central

    Huysseune, Ann; Soenens, Mieke; Elderweirdt, Fien

    2014-01-01

    The canonical (β-catenin dependent) Wnt signaling pathway has emerged as a likely candidate for regulating tooth replacement in continuously renewing dentitions. So far, the involvement of canonical Wnt signaling has been experimentally demonstrated predominantly in amniotes. These studies tend to show stimulation of tooth formation by activation of the Wnt pathway, and inhibition of tooth formation when blocking the pathway. Here, we report a strong and dynamic expression of the soluble Wnt inhibitor dickkopf1 (dkk1) in developing zebrafish (Danio rerio) tooth germs, suggesting an active repression of Wnt signaling during morphogenesis and cytodifferentiation of a tooth, and derepression of Wnt signaling during start of replacement tooth formation. To further analyse the role of Wnt signaling, we used different gain-of-function approaches. These yielded disjunct results, yet none of them indicating enhanced tooth replacement. Thus, masterblind (mbl) mutants, defective in axin1, mimic overexpression of Wnt, but display a normally patterned dentition in which teeth are replaced at the appropriate times and positions. Activating the pathway with LiCl had variable outcomes, either resulting in the absence, or the delayed formation, of first-generation teeth, or yielding a regular dentition with normal replacement, but no supernumerary teeth or accelerated tooth replacement. The failure so far to influence tooth replacement in the zebrafish by perturbing Wnt signaling is discussed in the light of (i) potential technical pitfalls related to dose- or time-dependency, (ii) the complexity of the canonical Wnt pathway, and (iii) species-specific differences in the nature and activity of pathway components. Finally, we emphasize the importance of in-depth knowledge of the wild-type pattern for reliable interpretations. It is hoped that our analysis can be inspiring to critically assess and elucidate the role of Wnt signaling in tooth development in polyphyodonts. PMID

  14. [Tooth regeneration in the guinea pig (Cavia porcellus)].

    PubMed

    Stephan, F; Artis, J P; Lanot, R

    1977-01-01

    The first inferior molar has been extracted, a part of its being reimplanted or not. A new molar of normal form regenerated, apparently from the apex of the tooth germ, in all cases in which the alveolus was left free or implanted with a tooth freagment deprived of pulpa.

  15. Inhibition of NOS-NO System Prevents Autoimmune Orchitis Development in Rats: Relevance of NO Released by Testicular Macrophages in Germ Cell Apoptosis and Testosterone Secretion

    PubMed Central

    Jarazo Dietrich, Sabrina; Fass, Mónica Irina; Jacobo, Patricia Verónica; Sobarzo, Cristian Marcelo Alejandro; Lustig, Livia; Theas, María Susana

    2015-01-01

    Background Although the testis is considered an immunoprivileged organ it can orchestrate immune responses against pathological insults such as infection and trauma. Experimental autoimmune orchitis (EAO) is a model of chronic inflammation whose main histopathological features it shares with human orchitis. In EAO an increased number of macrophages infiltrate the interstitium concomitantly with progressive germ cell degeneration and impaired steroidogenesis. Up-regulation of nitric oxide (NO)-NO synthase (NOS) system occurs, macrophages being the main producers of NO. Objective The aim of our study was to evaluate the role of NO-NOS system in orchitis development and determine the involvement of NO released by testicular macrophages on germ cell apoptosis and testosterone secretion. Method and Results EAO was induced in rats by immunization with testicular homogenate and adjuvants (E group) and a group of untreated normal rats (N) was also studied. Blockage of NOS by i.p. injection of E rats with a competitive inhibitor of NOS, L-NAME (8mg/kg), significantly reduced the incidence and severity of orchitis and lowered testicular nitrite content. L-NAME reduced germ cell apoptosis and restored intratesticular testosterone levels, without variations in serum LH. Co-culture of N testicular fragments with testicular macrophages obtained from EAO rats significantly increased germ cell apoptosis and testosterone secretion, whereas addition of L-NAME lowered both effects and reduced nitrite content. Incubation of testicular fragments from N rats with a NO donor DETA-NOnoate (DETA-NO) induced germ cell apoptosis through external and internal apoptotic pathways, an effect prevented by N-acetyl-L-cysteine (NAC). DETA-NO inhibited testosterone released from Leydig cells, whereas NAC (from 2.5 to 15 mM) did not prevent this effect. Conclusions We demonstrated that NO-NOS system is involved in the impairment of testicular function in orchitis. NO secreted mainly by testicular

  16. The regulation of tooth morphogenesis is associated with epithelial cell proliferation and the expression of Sonic hedgehog through epithelial-mesenchymal interactions

    SciTech Connect

    Ishida, Kentaro; Murofushi, Mayumi; Nakao, Kazuhisa; Morita, Ritsuko; Ogawa, Miho; Tsuji, Takashi

    2011-02-18

    Research highlights: {yields} Bioengineered teeth regulated the contact area of epithelium and mesenchyme. {yields} The crown width is regulated by the contact area of the epithelium and mesenchyme. {yields} This regulation is associated with cell proliferation and Sonic hedgehog expression. {yields} The cusp number is correlated with the crown width of the bioengineered tooth. {yields} Cell proliferation and Shh expression areas regulate the tooth morphogenesis. -- Abstract: Ectodermal organs, such as the tooth, salivary gland, hair, and mammary gland, develop through reciprocal epithelial-mesenchymal interactions. Tooth morphologies are defined by the crown width and tooth length (macro-morphologies), and by the number and locations of the cusp and roots (micro-morphologies). In our current study, we report that the crown width of a bioengineered molar tooth, which was reconstructed using dissociated epithelial and mesenchymal cells via an organ germ method, can be regulated by the contact area between epithelial and mesenchymal cell layers. We further show that this is associated with cell proliferation and Sonic hedgehog (Shh) expression in the inner enamel epithelium after the germ stage has formed a secondary enamel knot. We also demonstrate that the cusp number is significantly correlated with the crown width of the bioengineered tooth. These findings suggest that the tooth micro-morphology, i.e. the cusp formation, is regulated after the tooth width, or macro-morphology, is determined. These findings also suggest that the spatiotemporal patterning of cell proliferation and the Shh expression areas in the epithelium regulate the crown width and cusp formation of the developing tooth.

  17. New developments in Charcot-Marie-Tooth neuropathy and related diseases.

    PubMed

    Pareyson, Davide; Saveri, Paola; Pisciotta, Chiara

    2017-10-01

    Charcot-Marie-Tooth disease (CMT) and related neuropathies represent a heterogeneous group of hereditary disorders. The present review will discuss the most recent advances in the field. Knowledge of CMT epidemiology and frequency of the main associated genes is increasing, with an overall prevalence estimated at 10-28/100 000. In the last years, the huge number of newly uncovered genes, thanks to next-generation sequencing techniques, is challenging the current classification of CMT. During the last 18 months other genes have been associated with CMT, such as PMP2, MORC2, NEFH, MME, and DGAT2. For the most common forms of CMT, numerous promising compounds are under study in cellular and animal models, mainly targeting either the protein degradation pathway or the protein overexpression. Consequently, efforts are devoted to develop responsive outcome measures and biomarkers for this overall slowly progressive disorder, with quantitative muscle MRI resulting the most sensitive-to-change measure. This is a rapidly evolving field where better understanding of pathophysiology is paving the way to develop potentially effective treatments, part of which will soon be tested in patients. Intense research is currently devoted to prepare clinical trials and develop responsive outcome measures.

  18. Age estimation in Portuguese population: The application of the London atlas of tooth development and eruption.

    PubMed

    Pavlović, Strahinja; Palmela Pereira, Cristiana; Vargas de Sousa Santos, Rui Filipe

    2017-03-01

    Chronological age estimation from the dental parameters is becoming increasingly important. The London atlas of tooth development is the most recent developed method and represents a modification of the previous older methods. The aim of this study was to evaluate the accuracy of the London atlas for the dental age estimation in the Portuguese population. The study sample included 736 radiographic images (498 females and 238 males) of Portuguese origin, patients of Dental Clinic of Superior Institute of Health Sciences Egas Moniz and Dental Medicine Faculty, University of Lisbon. The age range of the individuals was between 3 and 24 years. Estimated age was compared with the chronological age using the paired t-test. The results showed that there was no statistically significant difference between left and right side of the jaw (p>0.05). Both sides showed an average overestimation of age by one month approximately. Moreover, the significant difference between chronological and estimated age was not observed in the females. However, the significant difference was observed in a sample coming from males (right: p=0.008; left: p=0.003). Our results showed that the London atlas can be potentially used as a tool for age estimation. However, the difference between sexes clearly suggests that separate charts should be made for each sex. Further studies, which will have as a final goal the development of a new method for age estimation using dental parameters, are needed.

  19. Risk of developing BRONJ among patients exposed to intravenous bisphosphonates following tooth extraction.

    PubMed

    Sanchis, Jose María; Bagán, Jose Vicente; Murillo, Judith; Díaz, Jose María; Asensio, Lucía

    2014-10-01

    A study was designed to measure of the incidence of bisphosphonate-related osteonecrosis of the jaws (BRONJ) following tooth extraction in patients receiving or who have received intravenous bisphosphonates (Zometa, zoledronic acid). A prospective cohort study was made of 36 patients subjected to 62 tooth extractions. All these 36 patients had been treated or were receiving treatment with zoledronic acid. The incidence of BRONJ following 62 tooth extractions in patients treated with zoledronic acid 4 months after extraction was 14.5%. No statistically significant associations were found with patient age, sex, hygiene index, total treatment time, surgical difficulty, or extraction site. However, the factors that significantly influenced the final presence of osteonecrosis were related to tooth extractions in the absence of periodontal disease, and if sockets remained unhealed at the month of extraction.

  20. Development of a new approach for targeted gene editing in primordial germ cells using TALENs in Xenopus

    PubMed Central

    Nakajima, Keisuke; Yaoita, Yoshio

    2015-01-01

    ABSTRACT A gene of interest can be efficiently modified using transcription activator-like effector nucleases (TALENs) (Christian et al., 2010;Li et al., 2011). However, if a target gene is essential for development, growth and fertility, use of TALENs with high mutagenic activity in F0 frogs could result in developmental disorders or sterility, which would reduce the number of F1 progeny and make F1 phenotypical analysis difficult. We used the 3′ untranslated region of DEADSouth gene (DS-3′) of Xenopus tropicalis to solve this problem, because the addition of the DS-3′ to mRNA is known to induce primordial germ cell (PGC)-specific expression and reduce the stability in somatic cells of mRNA in Xenopus laevis. At first, we inserted the X. tropicalis DS-3′ downstream of the EGFP termination codon and confirmed that the EGFP expression was specifically detected in PGCs for three weeks. Therefore, we inserted the DS-3′ downstream of the termination codon of the TALEN coding sequence. The tyrosinase gene was selected as the target gene for TALEN because the bi-allelic mutation of this gene is easily discernible by the albino phenotype. When fertilized eggs were microinjected with TALEN mRNAs fused to the DS-3′, their sperm and oocytes had a high rate (84–100%) of target-gene modification in contrast to the lower rate (0–45%) of nucleotide alteration observed in somatic cells. PMID:25661867

  1. Interaction between NANOS2 and the CCR4-NOT deadenylation complex is essential for male germ cell development in mouse.

    PubMed

    Suzuki, Atsushi; Saba, Rie; Miyoshi, Kei; Morita, Yoshinori; Saga, Yumiko

    2012-01-01

    Nanos is one of the evolutionarily conserved proteins implicated in germ cell development and we have previously shown that it interacts with the CCR4-NOT deadenylation complex leading to the suppression of specific RNAs. However, the molecular mechanism and physiological significance of this interaction have remained elusive. In our present study, we identify CNOT1, a component of the CCR4-NOT deadenylation complex, as a direct factor mediating the interaction with NANOS2. We find that the first 10 amino acids (AAs) of NANOS2 are required for this binding. We further observe that a NANOS2 mutant lacking these first 10 AAs (NANOS2-ΔN10) fails to rescue defects in the Nanos2-null mouse. Our current data thus indicate that the interaction with the CCR4-NOT deadenylation complex is essential for NANOS2 function. In addition, we further demonstrate that NANOS2-ΔN10 can associate with specific mRNAs as well as wild-type NANOS2, suggesting the existence of other NANOS2-associated factor(s) that determine the specificity of RNA-binding independently of the CCR4-NOT deadenylation complex.

  2. Development of a new approach for targeted gene editing in primordial germ cells using TALENs in Xenopus.

    PubMed

    Nakajima, Keisuke; Yaoita, Yoshio

    2015-02-06

    A gene of interest can be efficiently modified using transcription activator-like effector nucleases (TALENs) (Christian et al., 2010;Li et al., 2011). However, if a target gene is essential for development, growth and fertility, use of TALENs with high mutagenic activity in F0 frogs could result in developmental disorders or sterility, which would reduce the number of F1 progeny and make F1 phenotypical analysis difficult. We used the 3' untranslated region of DEADSouth gene (DS-3') of Xenopus tropicalis to solve this problem, because the addition of the DS-3' to mRNA is known to induce primordial germ cell (PGC)-specific expression and reduce the stability in somatic cells of mRNA in Xenopus laevis. At first, we inserted the X. tropicalis DS-3' downstream of the EGFP termination codon and confirmed that the EGFP expression was specifically detected in PGCs for three weeks. Therefore, we inserted the DS-3' downstream of the termination codon of the TALEN coding sequence. The tyrosinase gene was selected as the target gene for TALEN because the bi-allelic mutation of this gene is easily discernible by the albino phenotype. When fertilized eggs were microinjected with TALEN mRNAs fused to the DS-3', their sperm and oocytes had a high rate (84-100%) of target-gene modification in contrast to the lower rate (0-45%) of nucleotide alteration observed in somatic cells.

  3. GERM as a tool for space station documentation

    NASA Technical Reports Server (NTRS)

    Crouse, Ken; Hardwick, Charles

    1990-01-01

    GERM as a tool for space station documentation is presented in the form of viewgraphs. The following subject areas are covered: problem statement, hypermedia as a tool for documentation, description of GERM, technical approach, application development, and results and conclusions.

  4. Over-expression of thymosin beta 4 promotes abnormal tooth development and stimulation of hair growth.

    PubMed

    Cha, Hee-Jae; Philp, Deborah; Lee, Soo-Hyun; Moon, Hye-Sung; Kleinman, Hynda K; Nakamura, Takashi

    2010-01-01

    Thymosin beta 4 has multi-functional roles in cell physiology. It accelerates wound healing, hair growth and angiogenesis, and increases laminin-5 expression in corneal epithelium. Furthermore, thymosin beta 4 stimulates tumor growth and metastasis by induction of cell migration and vascular endothelial growth factor-mediated angiogenesis. Using a construct on the skin-specific keratin-5 promoter, we have developed thymosin beta 4 over-expressing transgenic mice to further study its functional roles. Thymosin beta 4 in adult skin and in embryonic stages of the transgenic mouse was analyzed by both Western blot and immunohistochemistry. The over-expression of thymosin beta 4 was observed especially around hair follicles and in the teeth in the transgenic mice. We examined the phenotype of the thymosin beta 4 over-expressing mice. Hair growth was accelerated. In addition, the transgenic mice had abnormally-shaped white teeth and dull incisors. We found that the expression of laminin-5 was up-regulated in the skin of the transgenic mice. We conclude that thymosin beta 4 has an important physiological role in hair growth and in tooth development.

  5. Expression of Intermediate Filaments and Germ Cell Markers in the Developing Bovine Ovary: An Immunohistochemical and Laser-Assisted Microdissection Study.

    PubMed

    Kenngott, Rebecca Anna-Maria; Sauer, Ulrich; Vermehren, Margarete; Sinowatz, Fred

    2014-01-01

    In the present investigation, bovine ovary prenatal development was studied using immunohistochemistry and laser-assisted microdissection (LAM). A major aim of this study was to evaluate the protein expression pattern of intermediate filaments (IF) and distinguish S100 protein (S100 alpha and S100 beta protein) isoforms during prenatal follicle differentiation, subsequently correlating them with germ cell marker expression. A development-specific expression pattern of different keratins as well as vimentin was detected in the prenatal bovine ovary; K18-specific expression was found during all developmental stages (i.e. in surface epithelium, germ cell cord somatic cells, and follicle cells), and keratins 5, 7, 8, 14, and 19 and vimentin had a stage-specific expression pattern in the different cell populations of the prenatal ovaries. Additionally, our results represent new data on the expression pattern of germ cell markers during bovine ovary prenatal development. S100 alpha and beta protein was localized to oocyte cytoplasm of different follicle stages, and S100 alpha staining could be observed in granulosa cells. Furthermore, through isolation of characteristic ovary cell populations using LAM, specific confirmation of some genes of interest (KRT8, KRT18, S100 alpha, S100 beta, and OCT4, DDX4) could be obtained by RT-PCR in single cell groups of the developing bovine ovary. © 2015 S. Karger AG, Basel.

  6. [Development of prospective diapause-germs (Bombyx mori L.) in vitro without dormancy : II. Medium with foreign proteins (LYS) and extraembryonic deposits from different phases of egg diapause].

    PubMed

    Krause, Gerhard; Krause, Johanna

    1972-06-01

    When extraembryonic egg material is placed apart from prospective diapause germ anlagen or early germ bands, it will stimulate their development without dormancy via the medium. This method of a bipartial systemin vitro (21° C) helps to analyze the regulatory mechanisms involved in the egg diapause ofBombyx mori. 1. In preliminary experiments, a culture medium free of egg extracts but containing foreign proteins (LYS) proved useful, since 100% of the test germs reached dormancy in the absence of stored egg material. Mitoses decrease and morphogenesis decelerates until the stage of the fully segmented germ-band is reached, which means the end of the prediapausal period. 2. When eggs were opened they developedin vitro without egg diapause. One may assume that the access of free oxygen activates some regulatory mechanisms permitting development without dormancy (nondormancy=Nd). In addition, the separate deposit of chorion, serosa and yolk cells (CDS Depot) will in any case prevent dormancy. Thus, the factors responsible for egg diapause must be sought in the extraembryonic egg system. A direct contact between the extraembryonic action-system and the embryonic reactionsystem is not a prerequisite. TheLYS medium without deposits offers sufficient oxygen to the test germ. Therefore the prospective diapause germ possesses a tendency to dormancy, according to its reaction norm. The potency to stimulateNd was tested with various depotmaterials (C, D, S, CS, DS, CDS) removed from eggs during prediapause (21° C), diapause (3° C) and post-diapause (returned to 21° C for 4 days). Each material produced a specificNd rate.In vitro, the test germs can progress in their organogenesis optimally to the stage of a small larva. The means of a collective effect in development are determined and related to one of the nine possibledegrees of organogenesis. 3. In comparison to serosa and chorion, yolk material has the highest mean both inNd rate (68 %,n=219) and degree of

  7. Dynamic expression of DNMT3a and DNMT3b isoforms during male germ cell development in the mouse.

    PubMed

    La Salle, Sophie; Trasler, Jacquetta M

    2006-08-01

    In the male germ line, sequence-specific methylation patterns are initially acquired prenatally in diploid gonocytes and are further consolidated after birth during spermatogenesis. It is still unclear how DNA methyltransferases are involved in establishing and/or maintaining these patterns in germ cells, or how their activity is regulated. We compared the temporal expression patterns of the postulated de novo DNA methyltransferases DNMT3a and DNMT3b in murine male germ cells. Mitotic, meiotic and post-meiotic male germ cells were isolated, and expression of various transcript variants and isoforms of Dnmt3a and Dnmt3b was examined using Quantitative RT-PCR and Western blotting. We found that proliferating and differentiating male germ cells were marked by distinctive expression profiles. Dnmt3a2 and Dnmt3b transcripts were at their highest levels in type A spermatogonia, decreased dramatically in type B spermatogonia and preleptotene spermatocytes and rose again in leptotene/zygotene spermatocytes, while Dnmt3a expression was mostly constant, except in type B spermatogonia where it increased. In all cases, expression declined as pachynema progressed. At the protein level, DNMT3a was the predominant isoform in type B spermatogonia, while DNMT3a2, DNMT3b2, and DNMT3b3 were expressed throughout most of spermatogenesis, except in pachytene spermatocytes. We also detected DNMT3a2 and DNMT3b2 in round spermatids. Taken together, these data highlight the tightly regulated expression of these genes during spermatogenesis and provide evidence that DNMTs may be contributing differentially to the establishment and/or maintenance of methylation patterns in male germ cells.

  8. Function of Secretory Leukocyte Protease Inhibitor (SLPI) in Odontoblast During Mouse Tooth Development.

    PubMed

    Jeong, Je-O; Wang, Guanlin; Jeong, Soon-Jeong; Choi, Baik-Dong; Lee, Hye-Yon; Jeong, Moon-Jin

    2015-01-01

    Secretory leuckocyte protease inhibitor (SLPI) is thought as a regulating protein on the synthesis and degradation of matrix proteins. But there was no report of expression and function of SLPI on the tooth development, especially on the odontoblasts. As observed by in-situ hybridization and immunohistochemical analysis, SLPI was expressed in odontoblasts and predentin on post-natal day 4 (PN4). On PN10, SLPI was observed under the dentin and apical region including odontoblasts processes. Further, on PN15, expression of SLPI was the same pattern compared to PN10. SLPI was expressed under layer of the odontoblasts and in odontoblasts on PN20. Matrix metalloproteinase-2 (MMP-2) and -9 levels in SLPI/MDPC-23 cells were higher than that of the MDPC-23 cells. The gene expression of SLPI, bone sialoprotein (BSP), osteocalcin (OCN), osteonectin (ON), and collagen type I (Col I) was higher in SLPI/MDPC-23 than that of MDPC-23 cells and the expression of dentin sialophosphoprotein (DSPP) was lower in SLPI/MDPC-23. Taken together, our results suggest that SLPI may be a MMP-2 and -9 regulating molecule in odontoblasts during dentin matrix formation and acts as a signaling molecule for dentin matrix related proteins during odontoblasts differentiation and mineralization.

  9. Immunohistochemical expression of fibrillin-1 and fibrillin-2 during tooth development.

    PubMed

    Kira-Tatsuoka, M; Oka, K; Tsuruga, E; Ozaki, M; Sawa, Y

    2015-12-01

    Oxytalan fibers are categorized as a microfibril assembly without elastin deposition, and are unique components in the periodontal ligament (PDL). However, little is known about their formation during PDL development. To clarify the mechanisms of oxytalan fiber formation in developing PDL, we performed immunohistochemical analysis to detect the direct expression of fibrillin-1 and fibrillin-2, which are major components of microfibrils. Frozen sections of lower molars from mice at several stages of growth were prepared without chemical fixation and decalcification using the film transfer method. Immunostaining was performed with anti-fibrillin-1 and -2, and anticytokeratin antibodies. Fibrillin-1 was not expressed in the dental follicle during the crown forming stage. At postneonatal day 9, fibrillin-1 expression started with meshwork appearance between the epithelial cells from Hertwig's epithelial root sheath at the root dentin surface. Fibirillin-2 was detected much earlier than fibrillin-1 expression. Fibrillin-2 was expressed with a liner appearance, running parallel to the root axis in PDL, and was partially co-expressed with cytokeratin 14 expression in Hertwig's epithelial root sheath. Furthermore, we detected both fibrillin-1 and fibrillin-2 expression in human PDL. Fibrillin-1 was detected in fibers with a vertically oriented root axis in PDL. Fibrillin-2 was widely expressed in PDL, including around the epithelial cell rests of Malassez. Fibrillin-1 and fibrillin-2 were clearly co-expressed in thick fiber structures in human PDL. Our results suggest that both fibrillin-1 and fibrillin-2 expression is required to form thick oxytalan fibers in PDL. Based on the expression patterns for fibrillin-1 and fibrillin-2, they have different functions during tooth root and PDL development. Early expression of fibrillin-2 may regulate dental epithelial cell behavior during root and PDL development. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  10. Tooth Problems

    MedlinePlus

    ... saved.Start OverDiagnosisYour pain may be from a FRACTURED, CRACKED or LOOSE TOOTH.Self CareSave any pieces of the tooth, wrap ... OverDiagnosisYour pain may be from TEMPOROMANDIBULAR JOINT (TMJ) syndrome, a condition that affects the jaw.Self CareTry ...

  11. Nanosecond Pulsed Electric Field Suppresses Development of Eyes and Germ Cells through Blocking Synthesis of Retinoic Acid in Medaka (Oryzias latipes)

    PubMed Central

    Shiraishi, Eri; Hosseini, Hamid; Kang, Dong K.; Kitano, Takeshi; Akiyama, Hidenori

    2013-01-01

    Application of nanosecond pulsed electric fields (nsPEFs) has attracted rising attention in various scientific fields including medical, pharmacological, and biological sciences, although its effects and molecular mechanisms leading to the effects remain poorly understood. Here, we show that a single, high-intensity (10–30 kV/cm), 60-ns PEF exposure affects gene expression and impairs development of eyes and germ cells in medaka (Oryzias latipes). Exposure of early blastula stage embryos to nsPEF down-regulated the expression of several transcription factors which are essential for eye development, causing abnormal eye formation. Moreover, the majority of the exposed genetic female embryos showed a fewer number of germ cells similar to that of the control (unexposed) genetic male at 9 days post-fertilization (dpf). However, all-trans retinoic acid (atRA) treatment following the exposure rescued proliferation of germ cells and resumption of normal eye development, suggesting that the phenotypes induced by nsPEF are caused by a decrease of retinoic acid levels. These results confirm that nsPEFs induce novel effects during embryogenesis in medaka. PMID:23936463

  12. [Destructive and protective factors in the development of tooth-wear].

    PubMed

    Máté, Jász; Gábor, Varga; Zsuzsanna, Tóth

    2006-12-01

    The experience of the past decade proves that tooth wear occurs in an increasing number of cases in general dental practice. Tooth wear may have physical (abrasion and attrition) and/or chemical (erosion) origin. The primary physical causes are inadequate dental hygienic activities, bad oral habits or occupational harm. As for dental erosion, it is accelerated by the highly erosive foods and drinks produced and sold in the past decades, and the number of cases is also boosted by the fact that bulimia, anorexia nervosa and gastro-oesophageal reflux disease prevalence have become more common. The most important defensive factor against tooth wear is saliva, which protects teeth from the effect of acids. Tertiary dentin formation plays an important role in the protection of the pulp. Ideally, destructive and protective factors are in balance. Both an increase in the destructive forces, and the insufficiency of defense factors result in the disturbance of the equilibrium. This results in tooth-wear, which means an irreversible loss of dental hard tissue. The rehabilitation of the lost tooth material is often very difficult, irrespectively of whether it is needed because of functional or esthetic causes. For that reason, the dentist should carry out primary and secondary dental care and prevention more often, i.e. dental recall is indispensable every 4-6 months.

  13. The cusp of evolution and development: a model of cichlid tooth shape diversity.

    PubMed

    Streelman, J T; Webb, J F; Albertson, R C; Kocher, T D

    2003-01-01

    Tooth shape is a hallmark of repeated evolutionary radiations among cichlid fishes from East Africa. Cusp shape and number vary both within populations and among closely related species with different feeding behaviors and ecologies. Here, we use histology and scanning electron microscopy to chart the developmental trajectory of tooth shape differences in fishes from Lake Malawi. We demonstrate that species with bi- or tricuspid adult (replacement) teeth initially possess a first-generation unicuspid dentition. Notably, the timing of turnover from first-generation to replacement teeth differs among species and is correlated with feeding ecology. Next, we use field data for cichlid species with adult unicuspid, bicuspid, and tricuspid teeth to demonstrate a strong and positive relationship between the number of teeth in a row and tooth shape. We discuss cichlid tooth ontogeny in the context of morphogenetic models designed to explain the developmental basis of tooth shape variation in mammals. We suggest that the dramatic differences in cichlid dentitions can be explained by variation in the expression of common activators and inhibitors acting at multiple stages of odontogenesis.

  14. Hedgehog signaling regulates dental papilla formation and tooth size during zebrafish odontogenesis

    PubMed Central

    Yu, Jeffrey C.; Fox, Zachary D.B.; Crimp, James L.; Littleford, Hana E.; Jowdry, Andrea L.; Jackman, William R.

    2015-01-01

    Background Intercellular communication by the hedgehog cell signaling pathway is necessary for tooth development throughout the vertebrates, but it remains unclear which specific developmental signals control cell behavior at different stages of odontogenesis. To address this issue, we have manipulated hedgehog activity during zebrafish tooth development and visualized the results using confocal microscopy. Results We first established that reporter lines for dlx2b, fli1, NF-κB, and prdm1a are markers for specific subsets of tooth germ tissues. We then blocked hedgehog signaling with cyclopamine and observed a reduction or elimination of the cranial neural crest derived dental papilla, which normally contains the cells that later give rise to dentin-producing odontoblasts. Upon further investigation we observed that the dental papilla begins to form and then regresses in the absence of hedgehog signaling, through a mechanism unrelated to cell proliferation or apoptosis. We also found evidence of an isometric reduction in tooth size that correlates with the time of earliest hedgehog inhibition. Conclusions We hypothesize that these results reveal a previously uncharacterized function of hedgehog signaling during tooth morphogenesis, regulating the number of cells in the dental papilla and thereby controlling tooth size. PMID:25645398

  15. Hedgehog signaling regulates dental papilla formation and tooth size during zebrafish odontogenesis.

    PubMed

    Yu, Jeffrey C; Fox, Zachary D; Crimp, James L; Littleford, Hana E; Jowdry, Andrea L; Jackman, William R

    2015-04-01

    Intercellular communication by the hedgehog cell signaling pathway is necessary for tooth development throughout the vertebrates, but it remains unclear which specific developmental signals control cell behavior at different stages of odontogenesis. To address this issue, we have manipulated hedgehog activity during zebrafish tooth development and visualized the results using confocal microscopy. We first established that reporter lines for dlx2b, fli1, NF-κB, and prdm1a are markers for specific subsets of tooth germ tissues. We then blocked hedgehog signaling with cyclopamine and observed a reduction or elimination of the cranial neural crest derived dental papilla, which normally contains the cells that later give rise to dentin-producing odontoblasts. Upon further investigation, we observed that the dental papilla begins to form and then regresses in the absence of hedgehog signaling, through a mechanism unrelated to cell proliferation or apoptosis. We also found evidence of an isometric reduction in tooth size that correlates with the time of earliest hedgehog inhibition. We hypothesize that these results reveal a previously uncharacterized function of hedgehog signaling during tooth morphogenesis, regulating the number of cells in the dental papilla and thereby controlling tooth size. © 2015 Wiley Periodicals, Inc.

  16. In vivo epigenomic profiling of germ cells reveals germ cell molecular signatures.

    PubMed

    Ng, Jia-Hui; Kumar, Vibhor; Muratani, Masafumi; Kraus, Petra; Yeo, Jia-Chi; Yaw, Lai-Ping; Xue, Kun; Lufkin, Thomas; Prabhakar, Shyam; Ng, Huck-Hui

    2013-02-11

    The limited number of in vivo germ cells poses an impediment to genome-wide studies. Here, we applied a small-scale chromatin immunoprecipitation sequencing (ChIP-seq) method on purified mouse fetal germ cells to generate genome-wide maps of four histone modifications (H3K4me3, H3K27me3, H3K27ac, and H2BK20ac). Comparison of active chromatin state between somatic, embryonic stem, and germ cells revealed promoters and enhancers needed for stem cell maintenance and germ cell development. We found the nuclear receptor Nr5a2 motif to be enriched at a subset of germ cell cis-regulatory regions, and our results implicate Nr5a2 in germ cell biology. Interestingly, in germ cells, the H3K27me3 histone modification occurs more frequently at regions that are enriched for retrotransposons and MHC genes, indicating that these loci are specifically silenced in germ cells. Together, our study provides genome-wide histone modification maps of in vivo germ cells and reveals the molecular chromatin signatures of germ cells. Copyright © 2013 Elsevier Inc. All rights reserved.

  17. Temporal and spatial expression of TGF-beta2 in tooth crown development in mouse first lower molar.

    PubMed

    Li, J Y; Hu, B; Wang, X J; Wang, S L

    2008-01-01

    Transforming Growth Factor beta2 (TGF-beta2) is involved in the regulation of many important cellular processes during tooth development. In this study we systematically characterized the expression pattern of TGF-beta2 in vivo and further analyzed its possible roles during different developmental stages of mouse first lower molar using immunofluorescence histochemical method with confocal microscopy. TGF-beta2 signaling was detected in different developing stages in both dental epithelium and surrounding dental mesenchyme. For the first time, we found that the basement membrane and epithelial cells in the basal layer showed no immunostaining from embryonic day 11 to 13; the primary enamel knot and secondary enamel knot exhibited pronounced immunostaining with different expression patterns at embryonic day 14 and 16. In addition, the mature ameloblast lost immunoreactivity, but the secretory ameloblast still exhibited positive immunoreaction at day 2 of postnatal development. Collectively, the temporospatial distribution patterns of TGF- beta2, especially in the basement membrane, epithelial cells in the basal layer, enamel knot, mature odontoblast and ameloblast, suggested a close association between TGF-beta2 signaling and tooth crown development, and indicated that TGF-beta2 might participate in tooth initiation, epithelial morphogenesis, formation of dentine matrix, and ameloblast differentiation.

  18. The checkpointkinase 2 (CHK2) 1100delC germ line mutation is not associated with the development of squamous cell carcinoma of the head and neck (SCCHN)

    PubMed Central

    2010-01-01

    Background The checkpointkinase 2 (CHK2) is part of the highly conserved ATM-CHK2 signaling pathway, which is activated in response to DNA damage, in particular after double strand breaks which can be caused by carcinogens like smoking. After induction of downstream targets, e.g. the tumor suppressor p53, its activation leads to cell cycle arrest and apoptosis. Recently, the presence of CHK2 germ line mutations, primarily the 1100delC variant, has been reported to be involved in carcinogenesis. The CHK2 1100delC variant results in a truncated protein which is instable and inactive. Carriers of this variant have been shown to have an increased risk to develop breast cancer and probably also other tumors. Our purpose was to investigate the role of CHK2 germ line mutations in patients with squamous cell carcinoma of the head and neck (SCCHN). Materials and Methods We investigated 91 patients suffering from SCCHN including all tumor sites (oropharynx, hypopharynx, larynx) for the presence of the germ line mutation 1100delC by direct sequence analysis. Patients were characterized by their tumor localization, tumor stage, age, the presence of additional malignant tumors and predisposing carcinogens (smoking, alcohol abuse). Results None of the patients, independently of the tumor site, age, the abuse of predisposing carcinogens, or the presence of other kinds of tumors, carried the CHK2 1100delC variant. Conclusions The germ line CHK2 1100delC variant does not seem to have a major impact on the development of SCCHN. PMID:21184685

  19. Interaction between Fibronectin and β1 Integrin Is Essential for Tooth Development

    PubMed Central

    Yamada, Aya; Yuasa, Kenji; Yoshizaki, Keigo; Iwamoto, Tsutomu; Saito, Masahiro; Nakamura, Takashi; Fukumoto, Satoshi

    2015-01-01

    The dental epithelium and extracellular matrix interact to ensure that cell growth and differentiation lead to the formation of teeth of appropriate size and quality. To determine the role of fibronectin in differentiation of the dental epithelium and tooth formation, we analyzed its expression in developing incisors. Fibronectin mRNA was expressed during the presecretory stage in developing dental epithelium, decreased in the secretory and early maturation stages, and then reappeared during the late maturation stage. The binding of dental epithelial cells derived from postnatal day-1 molars to a fibronectin-coated dish was inhibited by the RGD but not RAD peptide, and by a β1 integrin-neutralizing antibody, suggesting that fibronectin-β1 integrin interactions contribute to dental epithelial-cell binding. Because fibronectin and β1 integrin are highly expressed in the dental mesenchyme, it is difficult to determine precisely how their interactions influence dental epithelial differentiation in vivo. Therefore, we analyzed β1 integrin conditional knockout mice (Intβ1lox-/lox-/K14-Cre) and found that they exhibited partial enamel hypoplasia, and delayed eruption of molars and differentiation of ameloblasts, but not of odontoblasts. Furthermore, a cyst-like structure was observed during late ameloblast maturation. Dental epithelial cells from knockout mice did not bind to fibronectin, and induction of ameloblastin expression in these cells by neurotrophic factor-4 was inhibited by treatment with RGD peptide or a fibronectin siRNA, suggesting that the epithelial interaction between fibronectin and β1 integrin is important for ameloblast differentiation and enamel formation. PMID:25830530

  20. Interaction between fibronectin and β1 integrin is essential for tooth development.

    PubMed

    Saito, Kan; Fukumoto, Emiko; Yamada, Aya; Yuasa, Kenji; Yoshizaki, Keigo; Iwamoto, Tsutomu; Saito, Masahiro; Nakamura, Takashi; Fukumoto, Satoshi

    2015-01-01

    The dental epithelium and extracellular matrix interact to ensure that cell growth and differentiation lead to the formation of teeth of appropriate size and quality. To determine the role of fibronectin in differentiation of the dental epithelium and tooth formation, we analyzed its expression in developing incisors. Fibronectin mRNA was expressed during the presecretory stage in developing dental epithelium, decreased in the secretory and early maturation stages, and then reappeared during the late maturation stage. The binding of dental epithelial cells derived from postnatal day-1 molars to a fibronectin-coated dish was inhibited by the RGD but not RAD peptide, and by a β1 integrin-neutralizing antibody, suggesting that fibronectin-β1 integrin interactions contribute to dental epithelial-cell binding. Because fibronectin and β1 integrin are highly expressed in the dental mesenchyme, it is difficult to determine precisely how their interactions influence dental epithelial differentiation in vivo. Therefore, we analyzed β1 integrin conditional knockout mice (Intβ1lox-/lox-/K14-Cre) and found that they exhibited partial enamel hypoplasia, and delayed eruption of molars and differentiation of ameloblasts, but not of odontoblasts. Furthermore, a cyst-like structure was observed during late ameloblast maturation. Dental epithelial cells from knockout mice did not bind to fibronectin, and induction of ameloblastin expression in these cells by neurotrophic factor-4 was inhibited by treatment with RGD peptide or a fibronectin siRNA, suggesting that the epithelial interaction between fibronectin and β1 integrin is important for ameloblast differentiation and enamel formation.

  1. Tooth whitening today.

    PubMed

    Sarrett, David C

    2002-11-01

    Methods to improve the esthetics of the dentition by tooth whitening are of interest to dentists, their patients and the public. In the past 20 years, research on bleaching and other methods of removing tooth discolorations has dramatically increased. Dentist-supervised and over-the-counter products now are available to solve a variety of tooth discoloration problems without restorative intervention. The indications for appropriate use of tooth-whitening methods and products are dependent on correct diagnosis of the discoloration. Tooth-whitening methods include the use of peroxide bleaching agents to remove internal discolorations or abrasive products to remove external stains. Peroxide bleaching procedures are completed by the dentist in single or multiple appointments, or by the patient over a period of weeks to months using custom trays loaded with a bleaching agent. Both methods are safe and effective when supervised by the dentist. Microabrasion is indicated for the removal of isolated discolorations that often are associated with fluorosis. Whitening toothpastes remove surface stains only through the polishing effect of the abrasives they contain. Tooth whitening is a form of dental treatment and should be completed as part of a comprehensive treatment plan developed by a dentist after an oral examination. When used appropriately, tooth-whitening methods are safe and effective.

  2. Extraction and demulsification of oil from wheat germ, barley germ, and rice bran using an aqueous enzymatic method

    USDA-ARS?s Scientific Manuscript database

    An aqueous enzymatic method was developed to extract oil from wheat germ. The parameters that influence oil yield were investigated, including wheat germ pretreatment, comparison of various industrial enzymes, pH, ratio of wheat germ to water, reaction time and demulsification. Pretreatment at 180ºC...

  3. Recommendations to enable drug development for inherited neuropathies: Charcot-Marie-Tooth and Giant Axonal Neuropathy

    PubMed Central

    Sames, Lori; Moore, Allison; Arnold, Renee; Ekins, Sean

    2014-01-01

    Approximately 1 in 2500 Americans suffer from Charcot-Marie-Tooth (CMT) disease. The underlying disease mechanisms are unique in most forms of CMT, with many point mutations on various genes causing a toxic accumulation of misfolded proteins. Symptoms of the disease often present within the first two decades of life, with CMT1A patients having reduced compound muscle and sensory action potentials, slow nerve conduction velocities, sensory loss, progressive distal weakness, foot and hand deformities, decreased reflexes, bilateral foot drop and about 5% become wheelchair bound. In contrast, the ultra-rare disease Giant Axonal Neuropathy (GAN) is frequently described as a recessively inherited condition that results in progressive nerve death. GAN usually appears in early childhood and progresses slowly as neuronal injury becomes more severe and leads to death in the second or third decade. There are currently no treatments for any of the forms of CMTs or GAN. We suggest that further clinical studies should analyse electrical impedance myography as an outcome measure for CMT. Further, additional quality of life (QoL) assessments for these CMTs are required, and we need to identify GAN biomarkers as well as develop new genetic testing panels for both diseases. We propose that using the Global Registry of Inherited Neuropathy (GRIN) could be useful for many of these studies. Patient advocacy groups and professional organizations (such as the Hereditary Neuropathy Foundation (HNF), Hannah's Hope Fund (HHF), The Neuropathy Association (TNA) and the American Association of Neuromuscular and Electrodiagnostic Medicine (AANEM) can play a central role in educating clinicians and patients. Undertaking these studies will assist in the correct diagnosis of disease recruiting patients for clinical studies, and will ultimately improve the endpoints for clinical trials. By addressing obstacles that prevent industry investment in various forms of inherited neuropathies, we can

  4. The cracked tooth.

    PubMed

    Zuckerman, G R

    1998-01-01

    Fractured molars and premolars are very common. Fractures usually result from cracks that develop and slowly extend until the tooth separates into buccal and lingual fragments. Sometimes, as these cracks expand, the patient exhibits symptoms of what is commonly referred to as "cracked tooth syndrome" (CTS). When CTS occurs, an opportunity exists to diagnose and treat these patients, to relieve their discomfort and prevent sequelae that would require more extensive treatment.

  5. Tooth abscess

    MedlinePlus

    ... tissue swelling within the tooth. This causes a toothache . The toothache may stop if pressure is relieved. But the ... tissue. Symptoms The main symptom is a severe toothache. The pain is continuous. It does not stop. ...

  6. Dentistry and molecular biology: a promising field for tooth agenesis management.

    PubMed

    Boeira Junior, Breno Ramos; Echeverrigaray, Sergio

    2012-04-01

    Tooth agenesis is the failure of tooth bud development, causing definitive absence of the tooth. It is the most common dental anomaly, affecting up to one-quarter of the general population. The main cause is related to abnormal function of specific genes which play key roles during odontogenesis, particularly MSX1 and PAX9. MSX1 is a transcription factor highly expressed in the mesenchyme of developing tooth germs, whereas PAX9 is a transcription factor that shows a direct relationship with craniofacial development, particularly the formation of the palate and teeth. Despite the high frequency of tooth agenesis, there are as yet only a restricted number of mutations in MSX1 and PAX9 that have been associated with non-syndromic tooth agenesis. Thus, a deeper analysis of the gene networks underlying this anomaly is imperative. By means of a literature review based on Medline, PubMed, Lilacs, NCBI, and STRING, performed between 1991 and 2010 and focused on etiologically associated mutations, this work aimed to assess the latest advances in the genetic etiology of tooth agenesis and to offer an insight into how they can assist dental practice in the near future. A better knowledge of the genetic networks underlying tooth agenesis will lead to better treatment options and, perhaps, a tool for early diagnosis possibly related to DNA examination based on polymorphic variants. Such a test based on DNA analysis may be available to and accessible by clinicians, resulting in a more accurate diagnosis and allowing for a better approach to this anomaly.

  7. Potential toxicity of engineered nanoparticles in mammalian germ cells and developing embryos: treatment strategies and anticipated applications of nanoparticles in gene delivery.

    PubMed

    Das, Joydeep; Choi, Yun-Jung; Song, Hyuk; Kim, Jin-Hoi

    2016-09-01

    Engineered nanoparticles (ENPs) offer technological advantages for a variety of industrial and consumer products as well as show promise for biomedical applications. Recent progress in the field of nanotechnology has led to increased exposure to nanoparticles by humans. To date, little is known about the adverse effects of these ENPs on reproductive health, although interest in nanotechnology area is growing. A few biocompatible ENPs have a high loading capacity for exogenous substances, including drugs, DNA or proteins, and can selectively deliver molecular cargo into cells; however, they represent a potential tool for gene delivery into gametes and embryos. Understanding the reprotoxicological aspects of these ENPs is of the utmost importance to reliably estimate its potential impact on human health. In addition, a search for protective agents to combat ENP-mediated reproductive toxicity is warranted. Therefore, in this review we summarize the toxic effects of a few ENPs (metal and metal oxides, carbon-based nanoparticles, quantum dots and chitosan) in mammalian germ cells and developing embryos, and propose some treatment strategies that could mitigate nanoparticle-mediated toxicity. In addition, we outline the anticipated applications of ENPs in transgenic animal production in order to generate models for investigations into the mechanisms for human disease. A literature search was performed using the National Center for Biotechnology Information PubMed database up until March 2016 and relevant keywords were used to obtain information regarding mammalian germ cell-specific toxicity and embryotoxicity of ENPs, possible treatment strategies, as well as the anticipated applications of nanoparticles in gene delivery in germ cells and embryos. Only English language publications were included. Here, we demonstrate the toxicological effects of ENPs in mammalian germ cells and developing embryos by considering both in vitro and in vivo experimental models based on the

  8. Development and implementation of the Clinical Tooth Shade Differentiation Course – an evaluation over 3 years

    PubMed Central

    Olms, Constanze; Haak, Rainer; Jakstat, Holger A.

    2016-01-01

    Objective: Tooth shade differentiation concerns the identification and classification of tooth shades. The objective of this project was to implement the Clinical Tooth Shade Differentiation Course in the preclinical stage of studies and to evaluate the students' perspective over a period of 3 years. Methodology: The course is planned for a duration of 10 weeks with two 45-minute sessions per semester week. The entire attendance time was 10:15 h. 2 lectures of 90 minutes each, 2 seminars of 60 min each and 2 teaching units with the phantom head and role playing took place. In addition to the various parameters of tooth shade, changes in tooth shade and the basics of dental esthetics, clinical procedures for manual and digital tooth shade determination were explained and practiced. 96% (69 of 72) of the students participated in the first evaluation in 2012/2013 (T1), and 68% of these were women. In the following year, 2013/2014 (T2), 92% (45 of 48 students) took part; 62% of these were women and 38% men. The 2014/2015 evaluation (T3) comprised 94% (45 of 48 students). Of these, 67% were women. Results: In the evaluation, the students gave the course a positive grade. The questions in "General/Organization" were given a mean (M) of 1.5 (SD=0.7) in T1 and T2 , and 1.2 (SD=0.3) in T3. The "Overall Assessment" yielded MT1=1.6 (SD=0.6), MT2=1.5 (SD=0.5) and MT3=1.1 (SD=0.3). In T1 and T2, the item "The instructor actively involved the students in the course" was given a mean of 2.1 (SD=0.9), and in T3 a mean of 1.2 (SD=0.5). Conclusions: The course presented here conceptually shows how practical dental skills can be taught in a theoretical and clinical context. Educational objectives from the role of a dental expert were taken from the national competence-based catalog of educational objectives for dentistry and can also be supplemented. The objectives can be transferred to other dental faculties. PMID:26958650

  9. Migratory ability of gonadal germ cells (GGCs) isolated from Ciconia boyciana and Geronticus eremita embryos into the gonad of developing chicken embryos

    PubMed Central

    NAKAJIMA, Yuki; FUKUDA, Haruka; ONUMA, Manabu; MURATA, Koichi; UEDA, Miya; SUNAGA, Emi; SHIRAISHI, Toshirou; TAJIMA, Atsushi

    2016-01-01

    We conducted experiments to evaluate the ability of gonadal germ cells (GGCs), isolated from the embryonic gonads of Ciconia boyciana or Geronticus eremita, to migrate into the gonads of developing chicken embryos. Fluorescently labeled GGCs, isolated by the PBS (−) method, were transferred into the dorsal aorta of 2-day-old chicken embryos. Five days after transfer, fluorescent GGCs were detected in the gonads of recipient embryos. Our results indicate that GGCs from Ciconia boyciana and Geronticus eremita are capable of migrating into the gonads of developing chicken embryos. PMID:26922915

  10. Third molar development: evaluation of nine tooth development registration techniques for age estimations.

    PubMed

    Thevissen, Patrick W; Fieuws, Steffen; Willems, Guy

    2013-03-01

    Multiple third molar development registration techniques exist. Therefore the aim of this study was to detect which third molar development registration technique was most promising to use as a tool for subadult age estimation. On a collection of 1199 panoramic radiographs the development of all present third molars was registered following nine different registration techniques [Gleiser, Hunt (GH); Haavikko (HV); Demirjian (DM); Raungpaka (RA); Gustafson, Koch (GK); Harris, Nortje (HN); Kullman (KU); Moorrees (MO); Cameriere (CA)]. Regression models with age as response and the third molar registration as predictor were developed for each registration technique separately. The MO technique disclosed highest R(2) (F 51%, M 45%) and lowest root mean squared error (F 3.42 years; M 3.67 years) values, but differences with other techniques were small in magnitude. The amount of stages utilized in the explored staging techniques slightly influenced the age predictions. © 2013 American Academy of Forensic Sciences.

  11. Mathematical shape matching as a tool in tooth wear assessment--development and conduct.

    PubMed

    Mitchell, H L; Chadwick, R G

    1998-12-01

    The quantitative assessment of restoration and tooth wear usually requires fixed reference points from which measurements are made. In longitudinal patient follow-up the loss or erosion of such points may preclude measurement and an alternative approach is to seek regions of coincidence and conflict in digital models of before and after wear surfaces, with a continuous refinement of the parameters of the coordinate transformations, until the closest correspondence between them is found. A computer program has been written to implement the algorithm and assess the technique's capacity to find the match between surfaces both artificially generated and from tooth replicas recorded from patients at different epochs. The program was able to achieve the desired ends, demonstrating the utility of the technique in tooth wear assessment but identifying the need to refine the program further to enhance both its difference detection capabilities and level of automation. Examination of the theory and practical experience highlighted certain situations when user understanding is invaluable to ensure a satisfactory solution. This strengthened the investigators' resolve against reliance upon commercially based surface fitting programs whose basis may not be fully understood. Notwithstanding this surface matching is a powerful tool in the investigation of dental wear.

  12. Ectodysplasin regulates activator-inhibitor balance in murine tooth development through Fgf20 signaling

    PubMed Central

    Häärä, Otso; Harjunmaa, Enni; Lindfors, Päivi H.; Huh, Sung-Ho; Fliniaux, Ingrid; Åberg, Thomas; Jernvall, Jukka; Ornitz, David M.; Mikkola, Marja L.; Thesleff, Irma

    2012-01-01

    Uncovering the origin and nature of phenotypic variation within species is the first step in understanding variation between species. Mouse models with altered activities of crucial signal pathways have highlighted many important genes and signal networks regulating the morphogenesis of complex structures, such as teeth. The detailed analyses of these models have indicated that the balanced actions of a few pathways regulating cell behavior modulate the shape and number of teeth. Currently, however, most mouse models studied have had gross alteration of morphology, whereas analyses of more subtle modification of morphology are required to link developmental studies to evolutionary change. Here, we have analyzed a signaling network involving ectodysplasin (Eda) and fibroblast growth factor 20 (Fgf20) that subtly affects tooth morphogenesis. We found that Fgf20 is a major downstream effector of Eda and affects Eda-regulated characteristics of tooth morphogenesis, including the number, size and shape of teeth. Fgf20 function is compensated for by other Fgfs, in particular Fgf9 and Fgf4, and is part of an Fgf signaling loop between epithelium and mesenchyme. We showed that removal of Fgf20 in an Eda gain-of-function mouse model results in an Eda loss-of-function phenotype in terms of reduced tooth complexity and third molar appearance. However, the extra anterior molar, a structure lost during rodent evolution 50 million years ago, was stabilized in these mice. PMID:22833125

  13. Ectodysplasin regulates activator-inhibitor balance in murine tooth development through Fgf20 signaling.

    PubMed

    Häärä, Otso; Harjunmaa, Enni; Lindfors, Päivi H; Huh, Sung-Ho; Fliniaux, Ingrid; Åberg, Thomas; Jernvall, Jukka; Ornitz, David M; Mikkola, Marja L; Thesleff, Irma

    2012-09-01

    Uncovering the origin and nature of phenotypic variation within species is the first step in understanding variation between species. Mouse models with altered activities of crucial signal pathways have highlighted many important genes and signal networks regulating the morphogenesis of complex structures, such as teeth. The detailed analyses of these models have indicated that the balanced actions of a few pathways regulating cell behavior modulate the shape and number of teeth. Currently, however, most mouse models studied have had gross alteration of morphology, whereas analyses of more subtle modification of morphology are required to link developmental studies to evolutionary change. Here, we have analyzed a signaling network involving ectodysplasin (Eda) and fibroblast growth factor 20 (Fgf20) that subtly affects tooth morphogenesis. We found that Fgf20 is a major downstream effector of Eda and affects Eda-regulated characteristics of tooth morphogenesis, including the number, size and shape of teeth. Fgf20 function is compensated for by other Fgfs, in particular Fgf9 and Fgf4, and is part of an Fgf signaling loop between epithelium and mesenchyme. We showed that removal of Fgf20 in an Eda gain-of-function mouse model results in an Eda loss-of-function phenotype in terms of reduced tooth complexity and third molar appearance. However, the extra anterior molar, a structure lost during rodent evolution 50 million years ago, was stabilized in these mice.

  14. Germ line, stem cells, and epigenetic reprogramming.

    PubMed

    Surani, M A; Durcova-Hills, G; Hajkova, P; Hayashi, K; Tee, W W

    2008-01-01

    The germ cell lineage has the unique attribute of generating the totipotent state. Development of blastocysts from the totipotent zygote results in the establishment of pluripotent primitive ectoderm cells in the inner cell mass of blastocysts, which subsequently develop into epiblast cells in postimplantation embryos. The germ cell lineage in mice originates from these pluripotent epiblast cells of postimplantation embryos in response to specific signals. Pluripotent stem cells and unipotent germ cells share some fundamental properties despite significant phenotypic differences between them. Additionally, early primordial germ cells can be induced to undergo dedifferentiation into pluripotent embryonic germ cells. Investigations on the relationship between germ cells and pluripotent stem cells may further elucidate the nature of the pluripotent state. Furthermore, comprehensive epigenetic reprogramming of the genome in early germ cells, including extensive erasure of epigenetic modifications, is a critical step toward establishment of totipotency. The mechanisms involved may be relevant for gaining insight into events that lead to reprogramming of somatic cells into pluripotent stem cells.

  15. Specification of germ cell fate in mice.

    PubMed Central

    Saitou, Mitinori; Payer, Bernhard; Lange, Ulrike C; Erhardt, Sylvia; Barton, Sheila C; Surani, M Azim

    2003-01-01

    An early fundamental event during development is the segregation of germ cells from somatic cells. In many organisms, this is accomplished by the inheritance of preformed germ plasm, which apparently imposes transcriptional repression to prevent somatic cell fate. However, in mammals, pluripotent epiblast cells acquire germ cell fate in response to signalling molecules. We have used single cell analysis to study how epiblast cells acquire germ cell competence and undergo specification. Germ cell competent cells express Fragilis and initially progress towards a somatic mesodermal fate. However, a subset of these cells, the future primordial germ cells (PGCs), then shows rapid upregulation of Fragilis with concomitant transcriptional repression of a number of genes, including Hox and Smad genes. This repression may be a key event associated with germ cell specification. Furthermore, PGCs express Stella and other genes, such as Oct-4 that are associated with pluripotency. While these molecules are also detected in mature oocytes as maternally inherited factors, their early role is to regulate development and maintain pluripotency, and they do not serve the role of classical germline determinants. PMID:14511483

  16. Bcl11b regulates enamel matrix protein expression and dental epithelial cell differentiation during rat tooth development.

    PubMed

    Li, Ziyue; Chen, Guoqing; Yang, Yaling; Guo, Weihua; Tian, Weidong

    2017-01-01

    Amelogenesis, beginning with thickened epithelial aggregation and ending with highly mineralized enamel formation, is a process mediated by a complex signaling network that involves several molecules, including growth and transcription factors. During early tooth development, the transcription factor B‑cell CLL/lymphoma 11B (Bcl11b) participates in dental epithelial cell proliferation and differentiation. However, whether it affects the postnatal regulation of enamel matrix protein expression and ameloblast differentiation remains unclear. To clarify the role of Bcl11b in enamel development, the present study initially detected the protein expression levels of Bcl11b during tooth development using immunohistochemistry, from the embryonic lamina stage to the postnatal period, and demonstrated that Bcl11b is predominantly restricted to cervical loop epithelial cells at the cap and bell stages, whereas expression is reduced in ameloblasts. Notably, the expression pattern of Bcl11b during tooth development differed between rats and mice. Knockdown of Bcl11b by specific small interfering RNA attenuated the expression of enamel‑associated genes, including amelogenin, X‑linked (Amelx), ameloblastin (Ambn), enamelin (Enam), kallikrein related peptidase 4 (Klk4), matrix metallopeptidase 20 and Msh homeobox 2 (Msx2). Chromatin immunoprecipitation assay verified that Msx2 was a transcriptional target of Bcl11b. However, overexpression of Msx2 resulted in downregulation of enamel‑associated genes, including Ambn, Amelx, Enam and Klk4. The present study suggested that Bcl11b serves a potentially important role in the regulation of ameloblast differentiation and enamel matrix protein expression. In addition, a complex feedback regulatory network may exist between Bcl11b and Msx2.

  17. Simultaneous Gene Deletion of Gata4 and Gata6 Leads to Early Disruption of Follicular Development and Germ Cell Loss in the Murine Ovary1

    PubMed Central

    Padua, Maria B.; Fox, Shawna C.; Jiang, Tianyu; Morse, Deborah A.; Tevosian, Sergei G.

    2014-01-01

    ABSTRACT Granulosa cell formation and subsequent follicular assembly are important for ovarian development and function. Two members of the GATA family of transcription factors, GATA4 and GATA6, are expressed in ovarian somatic cells early in development, and their importance in adult ovarian function has been recently highlighted. In this study, we demonstrated that the embryonic loss of Gata4 and Gata6 expression within the ovary results in a strong down-regulation of genes involved in the ovarian developmental pathway (Fst and Irx3) as well as diminished expression of the pregranulosa and granulosa cell markers SPRR2 and FOXL2, respectively. Postnatal ovaries deficient in both Gata genes show impaired somatic cell proliferation and arrested follicular development at the primordial stage, where oocytes are either enclosed by one layer of squamous granulosa cells or remain in germ cell nests/clusters. Furthermore, germ cell nests and primordial follicles are predominantly localized to the central region of the Sf1Cre; Gata4flox/flox Gata6flox/flox ovaries, where the boundary between the medulla and cortex is almost nonexistent. Lastly, most of the oocytes are lost early in development in conditional double mutant ovaries, which confirms the importance of normally differentiated granulosa cells as supporting cells for oocyte survival. Thus, both GATA4 and GATA6 proteins are fundamental regulators of granulosa cell differentiation and proliferation, and consequently of proper follicular assembly during normal ovarian development and function. PMID:24899573

  18. Expression profile of critical genes involved in FGF signaling pathway in the developing human primary dentition.

    PubMed

    Huang, Feng; Hu, Xiaoxiao; Fang, Chunni; Liu, Hong; Lin, Chensheng; Zhang, Yanding; Hu, Xuefeng

    2015-11-01

    Mammalian tooth development is regulated by paracrine signal molecules of several conserved family interactions between epithelium and mesenchyme. The expression patterns and regulative roles of FGF signaling have been extensively studied in the mouse odontogenesis; however, that is not well known in human tooth development. In order to unveil the molecular mechanisms that regulate human tooth morphogenesis, we examined the expression patterns of the critical molecules involved in FGF signaling pathway in the developing human tooth germ by in situ hybridization, immunohistochemistry, and real-time RT-PCR, including FGF ligands, receptors, and intracellular transducer. We found overlapping but distinct expression pattern of FGF ligands and receptors in the different stages and components. Expression of FGF4, FGF7, FGF8, and FGF9 persists widespread in human tooth mesenchyme, which is quite different to that of in mouse. FGFR1 may be the major receptor in regulate mechanisms of FGF signals in human tooth development. Real-time RT-PCR indeed confirmed the results of in situ hybridization. Results of K-Ras, p-ERK1/2, p-p38, p-JNK, and p-PDK1 expression reveal spatial and temporal patterns of FGF signaling during morphogenesis and organogenesis of human tooth germ. Activity of the FGF signaling transducer protein in human tooth germ was much higher than that of in mouse. Our results provided important FGF singling information in the developing process, pinpoint to the domains where the downstream target genes of FGF signaling can be sought, and enlightened our knowledge about the nature of FGF signaling in human tooth germ.

  19. BmprIa is required in mesenchymal tissue and has limited redundant function with BmprIb in tooth and palate development.

    PubMed

    Li, Lu; Lin, Minkui; Wang, Ying; Cserjesi, Peter; Chen, Zhi; Chen, YiPing

    2011-01-15

    The BMP signaling plays a pivotal role in the development of craniofacial organs, including the tooth and palate. BmprIa and BmprIb encode two type I BMP receptors that are primarily responsible for BMP signaling transduction. We investigated mesenchymal tissue-specific requirement of BmprIa and its functional redundancy with BmprIb during the development of mouse tooth and palate. BmprIa and BmprIb exhibit partially overlapping and distinct expression patterns in the developing tooth and palatal shelf. Neural crest-specific inactivation of BmprIa leads to formation of an unusual type of anterior clefting of the secondary palate, an arrest of tooth development at the bud/early cap stages, and severe hypoplasia of the mandible. Defective tooth and palate development is accompanied by the down-regulation of BMP-responsive genes and reduced cell proliferation levels in the palatal and dental mesenchyme. To determine if BmprIb could substitute for BmprIa during tooth and palate development, we expressed a constitutively active form of BmprIb (caBmprIb) in the neural crest cells in which BmprIa was simultaneously inactivated. We found that substitution of BmprIa by caBmprIb in neural rest cells rescues the development of molars and maxillary incisor, but the rescued teeth exhibit a delayed odontoblast and ameloblast differentiation. In contrast, caBmprIb fails to rescue the palatal and mandibular defects including the lack of lower incisors. Our results demonstrate an essential role for BmprIa in the mesenchymal component and a limited functional redundancy between BmprIa and BmprIb in a tissue-specific manner during tooth and palate development. Copyright © 2010 Elsevier Inc. All rights reserved.

  20. BmprIa is required in mesenchymal tissue and has limited redundant function with BmprIb in tooth and palate development

    PubMed Central

    Li, Lu; Lin, Minkui; Wang, Ying; Cserjesi, Peter; Chen, Zhi; Chen, YiPing

    2010-01-01

    The BMP signaling plays a pivotal role in the development of craniofacial organs, including the tooth and palate. BmprIa and BmprIb encode two type I BMP receptors that are primarily responsible for BMP signaling transduction. We investigated mesenchymal tissue-specific requirement of BmprIa and its functional redundancy with BmprIb during the development of mouse tooth and palate. BmprIa and BmprIb exhibit partially overlapping and distinct expression patterns in the developing tooth and palatal shelf. Neural crest specific inactivation of BmprIa leads to formation of an unusual type of anterior clefting of the secondary palate, an arrest of tooth development at the bud/early cap stages, and severe hypoplasia of the mandible. Defective tooth and palate development is accompanied by the down-regulation of BMP responsive genes and reduced cell proliferation levels in the palatal and dental mesenchyme. To determine if BmprIb could substitute for BmprIa during tooth and palate development, we expressed a constitutively active form of BmprIb (caBmprIb) in the neural crest cells in which BmprIa was simultaneously inactivated. We found that substitution of BmprIa by caBmprIb in neural rest cells rescues the development of molars and maxillary incisor, but the rescued teeth exhibit a delayed odontoblast and ameloblast differentiation. In contrast, caBmprIb fails to rescue the palatal and mandibular defects including the lack of lower incisors. Our results demonstrate an essential role for BmprIa in the mesenchymal component and a limited functional redundancy between BmprIa and BmprIb in a tissue specific manner during tooth and palate development. PMID:21034733

  1. Germ cell specification and regeneration in planarians.

    PubMed

    Newmark, P A; Wang, Y; Chong, T

    2008-01-01

    In metazoans, two apparently distinct mechanisms specify germ cell fate: Determinate specification (observed in animals including Drosophila, Caenorhabditis elegans, zebra fish, and Xenopus) uses cytoplasmic factors localized to specific regions of the egg, whereas epigenetic specification (observed in many basal metazoans, urodeles, and mammals) involves inductive interactions between cells. Much of our understanding of germ cell specification has emerged from studies of model organisms displaying determinate specification. In contrast, our understanding of epigenetic/inductive specification is less advanced and would benefit from studies of additional organisms. Freshwater planarians--widely known for their remarkable powers of regeneration--are well suited for studying the mechanisms by which germ cells can be induced. Classic experiments showed that planarians can regenerate germ cells from body fragments entirely lacking reproductive structures, suggesting that planarian germ cells could be specified by inductive signals. Furthermore, the availability of the genome sequence of the planarian Schmidtea mediterranea, coupled with the animal's susceptibility to systemic RNA interference (RNAi), facilitates functional genomic analyses of germ cell development and regeneration. Here, we describe recent progress in studies of planarian germ cells and frame some of the critical unresolved questions for future work.

  2. Histological analysis of spermatogenesis and the germ cell development strategy within the testis of the male Western Cottonmouth Snake, Agkistrodon piscivorus leucostoma.

    PubMed

    Gribbins, Kevin M; Rheubert, Justin L; Collier, Matthew H; Siegel, Dustin S; Sever, David M

    2008-11-20

    Cottonmouth (Agkistrodon piscivorus leucostoma) testes were examined histologically to determine the germ cell development strategy employed during spermatogenesis. Testicular tissues from Cottonmouths were collected monthly from swamps around Hammond, Louisiana. Pieces of testis were fixed in Trump's fixative, dehydrated in ethanol, embedded in Spurr's plastic, sectioned with an ultramicrotome, and stained with toluidine blue and basic fuchsin. Spermatogenesis within Cottonmouths occurs in two independent events within a single calendar year. The testes are active during the months of March-June and August-October with spermiation most heavily observed during April-May and October. To our knowledge, this is the first study that describes bimodal spermatogenesis occurring in the same year within the subfamily Crotalinae. During spermatogenesis, no consistent spatial relationships are observed between germ cell generations. Typically, either certain cell types were missing (spermatocytes) or the layering of 3-5 spermatids and/or spermatocytes within the same cross-section of seminiferous tubule prevented consistent spatial stages from occurring. This temporal pattern of sperm development is different from the spatial development found within birds and mammals, being more reminiscent of that seen in amphibians, and has now been documented within every major clade of reptile (Chelonia, Serpentes, Sauria, Crocodylia). This primitive-like sperm development, within a testis structurally similar to mammals and birds, may represent an intermediate testicular model within the basally positioned (phylogenetically) reptiles that may be evolutionarily significant.

  3. RNA binding protein Musashi-1 directly targets Msi2 and Erh during early testis germ cell development and interacts with IPO5 upon translocation to the nucleus.

    PubMed

    Sutherland, Jessie M; Sobinoff, Alexander P; Fraser, Barbara A; Redgrove, Kate A; Davidson, Tara-Lynne; Siddall, Nicole A; Koopman, Peter; Hime, Gary R; McLaughlin, Eileen A

    2015-07-01

    Controlled gene regulation during gamete development is vital for maintaining reproductive potential. During the process of gamete development, male germ cells experience extended periods of inactive transcription despite requirements for continued growth and differentiation. Spermatogenesis therefore provides an ideal model to study the effects of posttranscriptional control on gene regulation. During spermatogenesis posttranscriptional regulation is orchestrated by abundantly expressed RNA-binding proteins. One such group of RNA-binding proteins is the Musashi family, previously identified as a critical regulator of testis germ cell development and meiosis in Drosophila and also shown to be vital to sperm development and reproductive potential in the mouse. We focus in depth on the role and function of the vertebrate Musashi ortholog Musashi-1 (MSI1). Through detailed expression studies and utilizing our novel transgenic Msi1 testis-specific overexpression model, we have identified 2 unique RNA-binding targets of MSI1 in spermatogonia, Msi2 and Erh, and have demonstrated a role for MSI1 in translational regulation. We have also provided evidence to suggest that nuclear import protein, IPO5, facilitates the nuclear translocation of MSI1 to the transcriptionally silenced XY chromatin domain in meiotic pachytene spermatocytes, resulting in the release of MSI1 RNA-binding targets. This firmly establishes MSI1 as a master regulator of posttranscriptional control during early spermatogenesis and highlights the significance of the subcellular localization of RNA binding proteins in relation to their function.

  4. Relationship between pre-natal factors, the perinatal environment, motor development in the first year of life and the timing of first deciduous tooth emergence.

    PubMed

    Żądzińska, Elżbieta; Sitek, Aneta; Rosset, Iwona

    2016-01-01

    The emergence of deciduous teeth, despite being genetically determined, shows significant correlation with the pre-natal environment, maternal factors, method of infant feeding and also family socioeconomic status. However, reported results are often contradictory and rarely concern healthy, full-term children. The objective of this study was to evaluate the influence of pre-natal and maternal factors as well as the method of infant feeding on the timing of first deciduous tooth emergence in healthy, full-term infants and to examine the relationship between the psychomotor development rate and the age at first tooth. The database contained 480 records for healthy, term-born children (272 boys and 208 girls born at 37-42 weeks of gestation) aged 9-54 months. Multiple regression analysis and multi-factor analysis of variance were used to identify significant explanatory variables for the age at first tooth. The onset of deciduous tooth emergence is negatively correlated with birth weight and maternal smoking during pregnancy and positively correlated with breastfeeding and the age at which the child begins to sit up unaided. These factors have an additive effect on the age at first tooth. An earlier onset of tooth emergence in children exposed to maternal smoking during pregnancy seems to provide further evidence for disturbed foetal development in a smoke-induced hypoxic environment.

  5. Evolutionary aspects of the development of teeth and baleen in the bowhead whale.

    PubMed

    Thewissen, J G M; Hieronymus, Tobin L; George, John C; Suydam, Robert; Stimmelmayr, Raphaela; McBurney, Denise

    2017-04-01

    In utero, baleen whales initiate the development of several dozens of teeth in upper and lower jaws. These tooth germs reach the bell stage and are sometimes mineralized, but toward the end of prenatal life they are resorbed and no trace remains after birth. Around the time that the germs disappear, the keratinous baleen plates start to form in the upper jaw, and these form the food-collecting mechanism. Baleen whale ancestors had two generations of teeth and never developed baleen, and the prenatal teeth of modern fetuses are usually interpreted as an evolutionary leftover. We investigated the development of teeth and baleen in bowhead whale fetuses using histological and immunohistochemical evidence. We found that upper and lower dentition initially follow similar developmental pathways. As development proceeds, upper and lower tooth germs diverge developmentally. Lower tooth germs differ along the length of the jaw, reminiscent of a heterodont dentition of cetacean ancestors, and lingual processes of the dental lamina represent initiation of tooth bud formation of replacement teeth. Upper tooth germs remain homodont and there is no evidence of a secondary dentition. After these germs disappear, the oral epithelium thickens to form the baleen plates, and the protein FGF-4 displays a signaling pattern reminiscent of baleen plates. In laboratory mammals, FGF-4 is not involved in the formation of hair or palatal rugae, but it is involved in tooth development. This leads us to propose that the signaling cascade that forms teeth in most mammals has been exapted to be involved in baleen plate ontogeny in mysticetes. © 2017 Anatomical Society.

  6. Coordination of Cellular Dynamics Contributes to Tooth Epithelium Deformations

    PubMed Central

    Morita, Ritsuko; Kihira, Miho; Nakatsu, Yousuke; Nomoto, Yohei; Ogawa, Miho; Ohashi, Kazumasa; Mizuno, Kensaku; Tachikawa, Tetsuhiko; Ishimoto, Yukitaka; Morishita, Yoshihiro; Tsuji, Takashi

    2016-01-01

    The morphologies of ectodermal organs are shaped by appropriate combinations of several deformation modes, such as invagination and anisotropic tissue elongation. However, how multicellular dynamics are coordinated during deformation processes remains to be elucidated. Here, we developed a four-dimensional (4D) analysis system for tracking cell movement and division at a single-cell resolution in developing tooth epithelium. The expression patterns of a Fucci probe clarified the region- and stage-specific cell cycle patterns within the tooth germ, which were in good agreement with the pattern of the volume growth rate estimated from tissue-level deformation analysis. Cellular motility was higher in the regions with higher growth rates, while the mitotic orientation was significantly biased along the direction of tissue elongation in the epithelium. Further, these spatio-temporal patterns of cellular dynamics and tissue-level deformation were highly correlated with that of the activity of cofilin, which is an actin depolymerization factor, suggesting that the coordination of cellular dynamics via actin remodeling plays an important role in tooth epithelial morphogenesis. Our system enhances the understanding of how cellular behaviors are coordinated during ectodermal organogenesis, which cannot be observed from histological analyses. PMID:27588418

  7. Interplay Between MMP-9 and TIMP-2 Regulates Ameloblastoma Behavior and Tooth Morphogenesis.

    PubMed

    Nunia, Kalpana; Urs, Aadithya B; Kumar, Priya

    2016-01-01

    Matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) have been implicated in the local invasiveness of ameloblastoma. This study aims to assess the role of MMP-9 and TIMP-2 in regulating tumor progression in ameloblastomas, taking tooth germs as control. Formalin-fixed, paraffin-embedded tissue sections of 4 tooth germs and 32 ameloblastomas were immunohistochemically examined using antibodies against MMP-9 and TIMP-2. Strong MMP-9 positivity was seen in the epithelial component in both controls and solid multicystic ameloblastoma. Statistically significant difference was observed in the mean stromal MMP-9 immunoscores between follicular, acanthomatous, and granular ameloblastoma when compared with the tooth germ (P=0.004). TIMP-2 expression in the epithelial and mesenchymal components of solid multicystic ameloblastoma and tooth germ was weak as compared with MMP-9 expression. Highest mean epithelial TIMP-2 immunoscore was observed in follicular ameloblastoma and the difference was statistically significant between follicular and granular ameloblastoma (P=0.05). The comparison of mean stromal TIMP-2 immunoscores showed statistically significant difference between follicular subtype and tooth germ (P=0.048), with tooth germ showing least expression among the groups studied. Strong stromal expression of MMP-9 in ameloblastoma compared with tooth germ mesenchyme indicated the possibility of tumor induction with release of growth factors and cytokines, resulting in invasiveness of ameloblastoma. Epithelial TIMP-2 expression was associated with the least and most aggressive behavior of follicular and granular cell ameloblastoma, respectively. Stromal TIMP-2 expression reflected its role in regulating tumor progression in ameloblastoma and in regulating developmental processes in tooth germs by their inhibitory effect on MMP-9.

  8. [Retinoic acid signal pathway regulation of zebra fish tooth development through manipulation of the differentiation of neural crest].

    PubMed

    Liu, Xin; Huang, Xing; Xu, Zhiyun; Yang, Deqin

    2016-04-01

    To investigate the mechanism of retinoic acid (RA) signal in dental evolution, RA is used to explore the influence of the mechanism on neural crest's migration during the early stage of zebra fish embryos. We divided embryos of wild type and transgenic line zebra fish into three groups. 1 x 10(-7) to 6 x 10(-7) mol x L(-1) RA and 1 x 10(-7) mo x L(-1) 4-diethylaminobenzaldehyde (DEAB) were added into egg water at 24 hpf for 9 h. Dimethyl sulfoxid (DMSO) with the concentration was used as control group. Then, antisense probes of dlx2a, dlx2b, and barxl were formulated to perform whole-mount in situ hybridization to check the expressions of the genes in 48 hpf to 72 hpf embryos. We observed fluorescence of transgenic line in 4 dpf embryos. We obtained three mRNA probes successfully. Compared with DMSO control group, a low concentration (1 x 10(-7) mol x L(-1)) of RA could up-regulate the expression of mRNA (barx1, dlx2a) in neural crest. Obvious migration trend was observed toward the pharyngeal arch in which teeth adhered. Transgenic fish had spreading fluorescence tendency in pharyngeal arch. However, a high concentration (4 x 10(-7) mol x L(-1)) of RA malformed the embryos and killed them after treatment. One third of the embryos of middle concentration (3 x 10(-7) mo x L(-1)) exhibited delayed development. DEAB resulted in neural crest dysplasia. The expression of barxl and dlx2a were suppressed, and the appearance of dlx2b in tooth was delayed. RA signal pathway can regulate the progenitors of tooth by controlling the growth of the neural crest and manipulating tooth development

  9. [Retroperitoneal germ cell tumor].

    PubMed

    Borrell Palanca, A; García Garzón, J; Villamón Fort, R; Domenech Pérez, C; Martínez Lorente, A; Gunthner, S; García Sisamón, F

    1999-03-01

    We report a case of retroperitoneal extragonadal germ-cell tumor in an 17 years old patient who presented with aedema and pain in left inferior extremity asociated with hemopthysis caused by pulmonar metastasis, who was treated with chemotherapy and resection of residual mass and pulmonary nodes. Dyagnosis was stableshed by fine neadle aspiration biopsy of the wass. We comment on the difficult of stableshing differential dyagnosis between retroperitoneal extragonadal germ-cell tumor and metastasis of a testicular tumor. Dyagnosis is stableshed by the finding of a histologically malignant germ-cell tumor with normal testis. We considered physical examination and ecographyc exploration enough for a correct dyagnosis.

  10. The Biology of the Germ line in Echinoderms

    PubMed Central

    Wessel, Gary M.; Brayboy, Lynae; Fresques, Tara; Gustafson, Eric A.; Oulhen, Nathalie; Ramos, Isabela; Reich, Adrian; Swartz, S. Zachary; Yajima, Mamiko; Zazueta, Vanessa

    2014-01-01

    SUMMARY The formation of the germ line in an embryo marks a fresh round of reproductive potential. The developmental stage and location within the embryo where the primordial germ cells (PGCs) form, however, differs markedly among species. In many animals, the germ line is formed by an inherited mechanism, in which molecules made and selectively partitioned within the oocyte drive the early development of cells that acquire this material to a germ-line fate. In contrast, the germ line of other animals is fated by an inductive mechanism that involves signaling between cells that directs this specialized fate. In this review, we explore the mechanisms of germ-line determination in echinoderms, an early-branching sister group to the chordates. One member of the phylum, sea urchins, appears to use an inherited mechanism of germ-line formation, whereas their relatives, the sea stars, appear to use an inductive mechanism. We first integrate the experimental results currently available for germ line determination in the sea urchin, for which considerable new information is available, and then broaden the investigation to the lesser-known mechanisms in sea stars and other echinoderms. Even with this limited insight, it appears that sea stars, and perhaps the majority of the echinoderm taxon, rely on inductive mechanisms for germ-line fate determination. This enables a strongly contrasted picture for germ-line determination in this phylum, but one for which transitions between different modes of germ-line determination might now be experimentally addressed. PMID:23900765

  11. The biology of the germ line in echinoderms.

    PubMed

    Wessel, Gary M; Brayboy, Lynae; Fresques, Tara; Gustafson, Eric A; Oulhen, Nathalie; Ramos, Isabela; Reich, Adrian; Swartz, S Zachary; Yajima, Mamiko; Zazueta, Vanessa

    2014-08-01

    The formation of the germ line in an embryo marks a fresh round of reproductive potential. The developmental stage and location within the embryo where the primordial germ cells (PGCs) form, however, differs markedly among species. In many animals, the germ line is formed by an inherited mechanism, in which molecules made and selectively partitioned within the oocyte drive the early development of cells that acquire this material to a germ-line fate. In contrast, the germ line of other animals is fated by an inductive mechanism that involves signaling between cells that directs this specialized fate. In this review, we explore the mechanisms of germ-line determination in echinoderms, an early-branching sister group to the chordates. One member of the phylum, sea urchins, appears to use an inherited mechanism of germ-line formation, whereas their relatives, the sea stars, appear to use an inductive mechanism. We first integrate the experimental results currently available for germ-line determination in the sea urchin, for which considerable new information is available, and then broaden the investigation to the lesser-known mechanisms in sea stars and other echinoderms. Even with this limited insight, it appears that sea stars, and perhaps the majority of the echinoderm taxon, rely on inductive mechanisms for germ-line fate determination. This enables a strongly contrasted picture for germ-line determination in this phylum, but one for which transitions between different modes of germ-line determination might now be experimentally addressed.

  12. Regulation of germ cell function by SUMOylation

    PubMed Central

    Rodriguez, Amanda; Pangas, Stephanie A.

    2015-01-01

    Oogenesis and spermatogenesis are tightly regulated complex processes that are critical for fertility function. Germ cells undergo meiosis to generate haploid cells necessary for reproduction. Errors in meiosis, including the generation of chromosomal abnormalities, can result in reproductive defects and infertility. Meiotic proteins are regulated by post-translational modifications including SUMOylation, the covalent attachment of small ubiquitin-like modifier (SUMO) proteins. Here, we review the role of SUMO proteins in controlling germ cell development and maturation based on recent findings from mouse models. Several studies have characterized the localization of SUMO proteins in male and female germ cells. However, a deeper understanding of how SUMOylation regulates proteins with essential roles in oogenesis and spermatogenesis will provide useful insight into the underlying mechanisms of germ cell development and fertility. PMID:26374733

  13. Amoxicillin Use during Early Childhood and Fluorosis of Later Developing Tooth Zones

    PubMed Central

    Levy, Steven M.; Warren, John J.; Broffitt, Barbara

    2015-01-01

    Objectives Amoxicillin use has been reported to be associated with developmental defects on enamel surfaces. This analysis assessed the association between amoxicillin use and fluorosis on late-erupting permanent teeth. Methods As part of the Iowa Fluoride Study, subjects were followed from birth to 32 months with questionnaires every 3-4 months to gather information on fluoride intake and amoxicillin use (n=357 subjects for this analysis). Permanent tooth fluorosis on late-erupting zones was assessed by three trained dentists using the Fluorosis Risk Index (FRI) at approximately age 13. A case was defined as fluorosis if a subject had at least two FRI classification II zone scores of 2 or 3. Chi-square tests and logistic regression were used and relative risks and odds ratios were calculated. Results There were 113 cases and 244 controls. In bivariate analyses, amoxicillin use from 20-24 months significantly increased the risk of fluorosis on FRI classification II zones (44.2% vs 30.4%, RR=1.45, 95% CI 1.05-2.04), but other individual time periods did not. Multivariable logistic regression confirmed the increased risk of fluorosis for amoxicillin use from 20-24 months (OR=2.92, 95% CI=1.34-6.40), after controlling for otitis media, breast-feeding, and fluoride intake. Conclusions Amoxicillin use during early childhood could be a risk factor in the etiology of fluorosis on late-erupting permanent tooth zones, but further research is needed. PMID:21972463

  14. Ultrastructural Studies of Germ Cell Development and the Functions of Leydig Cells and Sertoli Cells associated with Spermatogenesis in Kareius bicoloratus (Teleostei, Pleuronectiformes, Pleuronectidae)

    PubMed Central

    Kang, Hee-Woong; Kim, Sung Hwan; Chung, Jae Seung

    2016-01-01

    The ultrastructures of germ cells and the functions of Leydig cells and Sertoli cells during spermatogenesis inmale Kareius bicoloratus (Pleuronectidae) were investigated by electron microscope observation. Each of the well-developed Leydig cells during active maturation division and before spermiation contained an ovoid vesicular nucleus, a number of smooth endoplasmic reticula, well-developed tubular or vesicular mitochondrial cristae, and several lipid droplets in the cytoplasm. It is assumed that Leydig cells are typical steroidogenic cells showing cytological characteristics associated with male steroidogenesis. No cyclic structural changes in the Leydig cells were observed through the year. However, although no clear evidence of steroidogenesis or of any transfer of nutrients from the Sertoli cells to spermatogenic cells was observed, cyclic structural changes in the Sertoli cells were observed over the year. During the period of undischarged germ cell degeneration after spermiation, the Sertoli cells evidenced a lysosomal system associated with phagocytic function in the seminiferous lobules. In this study, the Sertoli cells function in phagocytosis and the resorption of products originating from degenerating spermatids and spermatozoa after spermiation. The spermatozoon lacks an acrosome, as have been shown in all teleost fish spermatozoa. The flagellum or sperm tail of this species evidences the typical 9+2 array of microtubules. PMID:27294207

  15. Foodborne Germs and Illnesses

    MedlinePlus

    ... Germs Botulism Campylobacter Clostridium perfringens Cyclospora E. coli Listeria Norovirus Salmonella Shigella Vibrio For a more complete ... has a few surprising exceptions: Two foodborne bacteria, Listeria monocytogenes and Yersinia enterocolitica can actually grow at ...

  16. Fate mapping in embryos of Neoceratodus forsteri reveals cranial neural crest participation in tooth development is conserved from lungfish to tetrapods.

    PubMed

    Kundrát, Martin; Joss, Jean M P; Smith, Moya M

    2008-01-01

    Experimental evidence that the neural crest participates in tooth development in any osteichthyan fish has so far been lacking. Using vital dye cell-lineage tracking, we demonstrate that trigeminal stream neural crest cells contribute to the dental papilla of developing teeth in the Australian lungfish. Trigeminal neural crest cells labeled before migration have been traced during the earliest stages of tooth development. Neural crest cells from a single midbrain locus were relocated as ectomesenchyme in all developing teeth of the lungfish regardless of their topographical position in the dentition. These cells remain at the dental papilla interface and become cells committed to dentine production. Our findings provide the first cell-lineage evidence that cranial neural crest is fated to ectomesenchyme for tooth development and dentine production in the living sister-group to tetrapods. This shows that cranial neural crest contribution to teeth is conserved from this node on the tetrapod phylogeny.

  17. Smad4-Shh-Nfic signaling cascade-mediated epithelial-mesenchymal interaction is crucial in regulating tooth root development.

    PubMed

    Huang, Xiaofeng; Xu, Xun; Bringas, Pablo; Hung, Yee Ping; Chai, Yang

    2010-05-01

    Transforming growth factor beta (TGF-beta)/bone morphogenetic protein (BMP) signaling is crucial for regulating epithelial-mesenchymal interaction during organogenesis, and the canonical Smad pathway-mediated TGF-beta/BMP signaling plays important roles during development and disease. During tooth development, dental epithelial cells, known as Hertwig's epithelial root sheath (HERS), participate in root formation following crown development. However, the functional significance of HERS in regulating root development remains unknown. In this study we investigated the signaling mechanism of Smad4, the common Smad for TGF-beta/BMP signaling, in HERS in regulating root development. Tissue-specific inactivation of Smad4 in HERS results in abnormal enamel and dentin formation in K14-Cre;Smad4(fl/fl) mice. HERS enlarges but cannot elongate to guide root development without Smad4. At the molecular level, Smad4-mediated TGF-beta/BMP signaling is required for Shh expression in HERS and Nfic (nuclear factor Ic) expression in the cranial neural crest (CNC)-derived dental mesenchyme. Nfic is crucial for root development, and loss of Nfic results in a CNC-derived dentin defect similar to the one of K14-Cre;Smad4(fl/fl) mice. Significantly, we show that ectopic Shh induces Nfic expression in dental mesenchyme and partially rescues root development in K14-Cre;Smad4(fl/fl) mice. Taken together, our study has revealed an important signaling mechanism in which TGF-beta/BMP signaling relies on a Smad-dependent mechanism in regulating Nfic expression via Shh signaling to control root development. The interaction between HERS and the CNC-derived dental mesenchyme may guide the size, shape, and number of tooth roots.

  18. Specifying and protecting germ cell fate

    PubMed Central

    Strome, Susan; Updike, Dustin

    2015-01-01

    Germ cells are the special cells in the body that undergo meiosis to generate gametes and subsequently entire new organisms after fertilization, a process that continues generation after generation. Recent studies have expanded our understanding of the factors and mechanisms that specify germ cell fate, including the partitioning of maternally supplied ‘germ plasm’, inheritance of epigenetic memory and expression of transcription factors crucial for primordial germ cell (PGC) development. Even after PGCs are specified, germline fate is labile and thus requires protective mechanisms, such as global transcriptional repression, chromatin state alteration and translation of only germline-appropriate transcripts. Findings from diverse species continue to provide insights into the shared and divergent needs of these special reproductive cells. PMID:26122616

  19. Sex determination in mammalian germ cells

    PubMed Central

    Spiller, Cassy M; Bowles, Josephine

    2015-01-01

    Germ cells are the precursors of the sperm and oocytes and hence are critical for survival of the species. In mammals, they are specified during fetal life, migrate to the developing gonads and then undergo a critical period during which they are instructed, by the soma, to adopt the appropriate sexual fate. In a fetal ovary, germ cells enter meiosis and commit to oogenesis, whereas in a fetal testis, they avoid entry into meiosis and instead undergo mitotic arrest and mature toward spermatogenesis. Here, we discuss what we know so far about the regulation of sex-specific differentiation of germ cells, considering extrinsic molecular cues produced by somatic cells, as well as critical intrinsic changes within the germ cells. This review focuses almost exclusively on our understanding of these events in the mouse model. PMID:25791730

  20. Sex determination in mammalian germ cells.

    PubMed

    Spiller, Cassy M; Bowles, Josephine

    2015-01-01

    Germ cells are the precursors of the sperm and oocytes and hence are critical for survival of the species. In mammals, they are specified during fetal life, migrate to the developing gonads and then undergo a critical period during which they are instructed, by the soma, to adopt the appropriate sexual fate. In a fetal ovary, germ cells enter meiosis and commit to oogenesis, whereas in a fetal testis, they avoid entry into meiosis and instead undergo mitotic arrest and mature toward spermatogenesis. Here, we discuss what we know so far about the regulation of sex-specific differentiation of germ cells, considering extrinsic molecular cues produced by somatic cells, as well as critical intrinsic changes within the germ cells. This review focuses almost exclusively on our understanding of these events in the mouse model.

  1. Development of a quantitative method to monitor the effect of a tooth whitening agent.

    PubMed

    Amaechi, Bennett T; Higham, Susan M

    2002-01-01

    This study demonstrated a quantitative method for assessing the effect of a tooth whitening agent. Forty human teeth were stained with a tea solution, and randomly assigned to two groups (A, B) of twenty teeth. The teeth were subsequently treated with either sodium hypochlorite (NaOCL) or deionized distilled water (DDW) by intermittent immersion (60 seconds on each occasion) in a 1:10 dilution of NaOCL (group A) or DDW (group B). Prior to whitening and following each immersion, the color of the teeth at the stained spot was measured using ShadeEye-Ex Dental Chroma Meter and quantitative light-induced fluorescence (QLF). ShadeEye-Ex instantly gave a numerical value for the stain intensity, chroma (C), which is the average of three measurements taken automatically by the machine. QLF gave a quantitative value for the stain, delta Q (% mm2), following analysis of the fluorescence image of the tooth. Immersion was stopped after four readings when one specimen, in group A, was observed to have regained its natural color. There was a good correlation between C and delta Q with either NaOCL (Pearson correlation coefficient (r) = 0.974; p < 0.05) or DDW (r = 0.978; p < 0.05). With NaOCL, an inverse relationship observed between stain measurements, C (Linear fit correlation (R) = -0.982; p < 0.05) or delta Q (R = -0.988; p < 0.05) and exposure time correlated to a linear fit, but not with DDW. ANOVA showed a significant difference between the means (n = 20) of the reading at the measurement intervals (0, 60, 120 and 180 seconds) for both C (p < 0.001) and delta Q (p < 0.001) with NaOCL but not with DDW. In conclusion, the study highlighted the potential of ShadeEye-Ex Dental Chroma Meter as a tool for the quantitative assessment of the gradual change in shade of discolored teeth by tooth whitening products.

  2. Development and microstructure of tooth histotypes in the blue shark, Prionace glauca (Carcharhiniformes: Carcharhinidae) and the great white shark, Carcharodon carcharias (Lamniformes: Lamnidae).

    PubMed

    Moyer, Joshua K; Riccio, Mark L; Bemis, William E

    2015-07-01

    Elasmobranchs exhibit two distinct arrangements of mineralized tissues in the teeth that are known as orthodont and osteodont histotypes. Traditionally, it has been said that orthodont teeth maintain a pulp cavity throughout tooth development whereas osteodont teeth are filled with osteodentine and lack a pulp cavity when fully developed. We used light microscopy, scanning electron microscopy, and high-resolution micro-computed tomography to compare the structure and development of elasmobranch teeth representing the two histotypes. As an example of the orthodont histotype, we studied teeth of the blue shark, Prionace glauca (Carcharhiniformes: Carcharhinidae). For the osteodont histotype, we studied teeth of the great white shark, Carcharodon carcharias (Lamniformes: Lamnidae). We document similarities and differences in tooth development and the microstructure of tissues in these two species and review the history of definitions and interpretations of elasmobranch tooth histotypes. We discuss a possible correlation between tooth histotype and tooth replacement and review the history of histotype differentiation in sharks. We find that contrary to a long held misconception, there is no orthodentine in the osteodont teeth of C. carcharias.

  3. Biology of tooth replacement in amniotes

    PubMed Central

    Whitlock, John A; Richman, Joy M

    2013-01-01

    Tooth replacement is a common trait to most vertebrates, including mammals. Mammals, however, have lost the capacity for continuous tooth renewal seen in most other vertebrates, and typically have only 1–2 generations of teeth. Here, we review the mechanisms of tooth replacement in reptiles and mammals, and discuss in detail the current and historical theories on control of timing and pattern of tooth replacement and development. PMID:23788284

  4. Influence of tooth profile on the noncircular gear tooth contact

    NASA Astrophysics Data System (ADS)

    Cristescu, A.; Andrei, L.; Cristescu, B.

    2017-02-01

    With noncircular gears, the continuous modification of the tooth meshing, in terms of variation of the tooth profiles and the line of action position and inclination, makes difficult the implementation of a general standard procedure for the analysis of the noncircular gears tooth contact. In this paper, the authors present a graphical approach that enables the tooth contact static pattern to be produced and evaluated in case of a noncircular gear with complex geometry of the pitch curve. The study is virtually developed, in AutoCAD environment, by animating and investigating the gear solid models in mesh. The tooth static contact analysis enables the path of contact area and distribution to be evaluated in correlation with the following variable initial data: gear pitch curve geometry, tooth profile geometry, as a consequence of different generating procedures, and the gear pressure angle. It was found out that the noncircular gear tooth contact could be improved by choosing different procedures for the tooth flank generation in concave and convex zones and by increasing the gear pressure angle.

  5. Dissecting Germ Cell Metabolism through Network Modeling.

    PubMed

    Whitmore, Leanne S; Ye, Ping

    2015-01-01

    Metabolic pathways are increasingly postulated to be vital in programming cell fate, including stemness, differentiation, proliferation, and apoptosis. The commitment to meiosis is a critical fate decision for mammalian germ cells, and requires a metabolic derivative of vitamin A, retinoic acid (RA). Recent evidence showed that a pulse of RA is generated in the testis of male mice thereby triggering meiotic commitment. However, enzymes and reactions that regulate this RA pulse have yet to be identified. We developed a mouse germ cell-specific metabolic network with a curated vitamin A pathway. Using this network, we implemented flux balance analysis throughout the initial wave of spermatogenesis to elucidate important reactions and enzymes for the generation and degradation of RA. Our results indicate that primary RA sources in the germ cell include RA import from the extracellular region, release of RA from binding proteins, and metabolism of retinal to RA. Further, in silico knockouts of genes and reactions in the vitamin A pathway predict that deletion of Lipe, hormone-sensitive lipase, disrupts the RA pulse thereby causing spermatogenic defects. Examination of other metabolic pathways reveals that the citric acid cycle is the most active pathway. In addition, we discover that fatty acid synthesis/oxidation are the primary energy sources in the germ cell. In summary, this study predicts enzymes, reactions, and pathways important for germ cell commitment to meiosis. These findings enhance our understanding of the metabolic control of germ cell differentiation and will help guide future experiments to improve reproductive health.

  6. Evaluation of the non-functional tooth contact in patients with temporomandibular disorders by using newly developed electronic system.

    PubMed

    Funato, M; Ono, Y; Baba, K; Kudo, Y

    2014-03-01

    The aims of this study were to introduce a novel electronic system for reliable evaluation of the non-functional tooth contact in patients with temporomandibular disorders (TMDs) and investigate the possible associations between the non-functional tooth contact and some characteristics of the patients with TMD. We designed and installed a software program to send emails regarding the non-functional tooth contact to the subjects' preregistered cellular phones at intervals of 20 ± 9 min daily for 10 consecutive days. Twelve patients with TMD and 12 gender- and age-matched healthy subjects responded via emails to one of 3 choices: no tooth contact, tooth contact during oral functions or tooth contact not associated with oral functions. The influence of subjective stress, anxiety, depression, personality and daily activities on tooth contact was then assessed. The frequency of the non-functional tooth contact was significantly higher in the patients with TMD than in the healthy subjects (35·0% vs. 9·6%, P < 0·001), while no significant group difference was found for the frequency of functional tooth contact, the stress, anxiety, depression and personality.

  7. Evaluation of the non-functional tooth contact in patients with temporomandibular disorders by using newly developed electronic system

    PubMed Central

    Funato, M; Ono, Y; Baba, K; Kudo, Y

    2014-01-01

    The aims of this study were to introduce a novel electronic system for reliable evaluation of the non-functional tooth contact in patients with temporomandibular disorders (TMDs) and investigate the possible associations between the non-functional tooth contact and some characteristics of the patients with TMD. We designed and installed a software program to send emails regarding the non-functional tooth contact to the subjects' preregistered cellular phones at intervals of 20 ± 9 min daily for 10 consecutive days. Twelve patients with TMD and 12 gender- and age-matched healthy subjects responded via emails to one of 3 choices: no tooth contact, tooth contact during oral functions or tooth contact not associated with oral functions. The influence of subjective stress, anxiety, depression, personality and daily activities on tooth contact was then assessed. The frequency of the non-functional tooth contact was significantly higher in the patients with TMD than in the healthy subjects (35·0% vs. 9·6%, P < 0·001), while no significant group difference was found for the frequency of functional tooth contact, the stress, anxiety, depression and personality. PMID:24447128

  8. A case-control study of the association between tooth-development gene polymorphisms and non-syndromic hypodontia in the Chinese Han population.

    PubMed

    Liu, Haochen; Zhang, Jin; Song, Shujuan; Zhao, Hongshan; Han, Dong; Feng, Hailan

    2012-10-01

    Hypodontia is one of the most common anomalies of human dentition. Recent genetic studies provide information on a number of genes related to both syndromic and non-syndromic forms of hypodontia. Fifty putative single nucleotide polymorphisms (SNPs) in 20 genes that play important roles in tooth development were selected, and a case-control study was conducted in 273 subjects with hypodontia (cases) and 200 subjects without hypodontia (controls). DNA was obtained from samples of whole blood or saliva. Genotyping was performed by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS). A significant difference was observed, between subjects with non-syndromic hypodontia and controls, in the allele and genotype frequencies of two markers [rs929387 of GLI family zinc finger 3 (GLI3) and rs11001553 of Dickkopf-related protein 1 (DKK1)]. Similar results were observed in a subgroup analysis of test subjects (stratified by gender or missing tooth position). However, this analysis showed no significant difference in the haplotype distribution between the controls and the affected subjects. These data demonstrate an association between some SNPs in tooth development-associated genes and sporadic non-syndromic hypodontia in Chinese Han individuals. This information may provide further understanding of the molecular mechanisms of tooth agenesis. Furthermore, these genes can be regarded as candidates for mutation detection in individuals with tooth agenesis. © 2012 Eur J Oral Sci.

  9. Sex Specification and Heterogeneity of Primordial Germ Cells in Mice.

    PubMed

    Sakashita, Akihiko; Kawabata, Yukiko; Jincho, Yuko; Tajima, Shiun; Kumamoto, Soichiro; Kobayashi, Hisato; Matsui, Yasuhisa; Kono, Tomohiro

    2015-01-01

    In mice, primordial germ cells migrate into the genital ridges by embryonic day 13.5 (E13.5), where they are then subjected to a sex-specific fate with female and male primordial germ cells undergoing mitotic arrest and meiosis, respectively. However, the sex-specific basis of primordial germ cell differentiation is poorly understood. The aim of this study was to investigate the sex-specific features of mouse primordial germ cells. We performed RNA-sequencing (seq) of E13.5 female and male mouse primordial germ cells using next-generation sequencing. We identified 651 and 428 differentially expressed transcripts (>2-fold, P < 0.05) in female and male primordial germ cells, respectively. Of these, many transcription factors were identified. Gene ontology and network analysis revealed differing functions of the identified female- and male-specific genes that were associated with primordial germ cell acquisition of sex-specific properties required for differentiation into germ cells. Furthermore, DNA methylation and ChIP-seq analysis of histone modifications showed that hypomethylated gene promoter regions were bound with H3K4me3 and H3K27me3. Our global transcriptome data showed that in mice, primordial germ cells are decisively assigned to a sex-specific differentiation program by E13.5, which is necessary for the development of vital germ cells.

  10. Pneumomediastinum after Tooth Extraction

    PubMed Central

    Ocakcioglu, Ilhan; Koyuncu, Serhat; Kupeli, Mustafa; Bol, Oguzhan

    2016-01-01

    Pneumomediastinum is defined as the presence of air in mediastinum. Pneumomediastinum can sometimes occur after surgery. Pneumomediastinum seen after dental procedures is rare. We presented the case of subcutaneous emphysema developed in the neck and upper chest after tooth extraction and discussed the possible mechanisms of pneumomediastinum. PMID:26989552

  11. Lin28a regulates germ cell pool size and fertility

    PubMed Central

    Shinoda, Gen; de Soysa, T. Yvanka; Seligson, Marc T.; Yabuuchi, Akiko; Fujiwara, Yuko; Huang, Pei Yi; Hagan, John P.; Gregory, Richard I.; Moss, Eric G.; Daley, George Q.

    2013-01-01

    Overexpression of LIN28A is associated with human germ cell tumors and promotes primordial germ cell (PGC) development from embryonic stem cells in vitro and in chimeric mice. Knockdown of Lin28a inhibits PGC development in vitro, but how constitutional Lin28a deficiency affects the mammalian reproductive system in vivo remains unknown. Here, we generated Lin28a knockout (KO) mice and found that Lin28a deficiency compromises the size of the germ cell pool in both males and females by affecting PGC proliferation during embryogenesis. Interestingly however, in Lin28a KO males the germ cell pool partially recovers during postnatal expansion, while fertility remains impaired in both males and females mated to wild type mice. Embryonic overexpression of let-7, a microRNA negatively regulated by Lin28a, reduces the germ cell pool, corroborating the role of the Lin28a/let-7 axis in regulating the germ lineage. PMID:23378032

  12. Regulation of germ cell meiosis in the fetal ovary.

    PubMed

    Spiller, Cassy M; Bowles, Josephine; Koopman, Peter

    2012-01-01

    Fertility depends on correct regulation of meiosis, the special form of cell division that gives rise to haploid gametes. In female mammals, germ cells enter meiosis during fetal ovarian development, while germ cells in males avoid entering meiosis until puberty. Decades of research have shown that meiotic entry, and germ cell sex determination, are not initiated intrinsically within the germ cells. Instead, meiosis is induced by signals produced by the surrounding somatic cells. More recently, retinoic acid (RA), the active derivative of vitamin A, has been implicated in meiotic induction during fetal XX and postnatal XY germ cell development. Evidence for an intricate system of RA synthesis and degradation in the fetal ovary and testis has emerged, explaining past observations of infertility in vitamin A-deficient rodents. Here we review how meiosis is triggered in fetal ovarian germ cells, paying special attention to the role of RA in this process.

  13. [Testicular germ cell tumors].

    PubMed

    Dourthe, L M; Ouachet, M; Fizazi, K; Droz, J P

    1998-09-01

    Testicle germ cells tumors are the most common young men neoplasm. The incidence is maximal in Scandinavian countries. Cryptorchidism is a predisposing factor. Diagnosis is clinic, first treatment is radical orchidectomy by inguinal incision, after study of tumor markers. Histology shows seminoma or non seminomatous tumor. Carcinoma in situ is the precursor of invasive germ cell tumors. Germ cell tumors have no p53 mutation, and have isochrome of the short arm of chromosome 12 as a specific marker. With the results of histological, biochemical and radiographic evaluation, patient are classified as follows: good, intermediate and poor risk prognosis. Standard treatment of stage I seminoma is prophylactic irradiation. Stage II with less than 3 cm lymph node too. Other situations need a cisplatin based chemotherapy. In case of metastatic residuals masses more than 3 cm, surgery need to be discussed. Stage I non seminomatous germ cell tumors are treated by retroperitoneal lymphadenectomy, by surveillance or by two cycles of adjuvant chemotherapy with cisplatin, etoposide and bleomycin (BEP). Standard treatment of good prognosis stage II and III is three cycles of BEP, four for poor prognosis. Residual mass need surgery, adjuvant chemotherapy is necessary in presence of viable germ cell. Standard treatment for relapses is chemotherapy with cisplatin, ifosfamide and vinblastine with a 30% remission rate. The place of high dose chemotherapy with autologous stem cell transplantation is not yet standardised. New drugs, as paclitaxel, are under studies.

  14. The Biology Underlying Abnormalities of Tooth Number in Humans.

    PubMed

    Juuri, E; Balic, A

    2017-10-01

    In past decades, morphologic, molecular, and cellular mechanisms that govern tooth development have been extensively studied. These studies demonstrated that the same signaling pathways regulate development of the primary and successional teeth. Mutations of these pathways lead to abnormalities in tooth development and number, including aberrant tooth shape, tooth agenesis, and formation of extra teeth. Here, we summarize the current knowledge on the development of the primary and successional teeth in animal models and describe some of the common tooth abnormalities in humans.

  15. Finding their way: themes in germ cell migration

    PubMed Central

    Barton, Lacy J.; LeBlanc, Michelle G.; Lehmann, Ruth

    2016-01-01

    Embryonic germ cell migration is a vital component of the germline lifecycle. The translocation of germ cells from the place of origin to the developing somatic gonad involves several processes including passive movements with underlying tissues, transepithelial migration, cell adhesion dynamics, the establishment of environmental guidance cues and the ability to sustain directed migration. How germ cells accomplish these feats in established model organisms will be discussed in this review, with a focus on recent discoveries and themes conserved across species. PMID:27484857

  16. Age estimation and the developing third molar tooth: an analysis of an Australian population using computed tomography.

    PubMed

    Bassed, Richard B; Briggs, C; Drummer, Olaf H

    2011-09-01

    The third molar tooth is one of the few anatomical sites available for age estimation of unknown age individuals in the late adolescent years. Computed tomography (CT) images were assessed in an Australian population aged from 15 to 25 years for development trends, particularly concerning age estimation at the child/adult transition point of 18 years. The CT images were also compared to conventional radiographs to assess the developmental scoring agreement between the two and it was found that agreement of Demirjian scores between the two imaging modalities was excellent. The relatively wide age ranges (mean ± 2SD) indicate that the third molar is not a precise tool for age estimation (age ranges of 3-8 years) but is, however, a useful tool for discriminating the adult/child transition age of 18 years. In the current study 100% of females and 96% of males with completed roots were over 18 years of age.

  17. A variant c-KIT mutation, D816H, fundamental to the sequential development of an ovarian mixed germ cell tumor and systemic mastocytosis with chronic myelomonocytic leukemia.

    PubMed

    Mitchell, Sarah G; Bunting, Silvia T; Saxe, Debra; Olson, Thomas; Keller, Frank G

    2017-04-01

    An activating point mutation of the c-KIT tyrosine kinase receptor gene, D816H, has been described in germ cell tumors (GCTs). We report an adolescent diagnosed with an ovarian mixed GCT and systemic mastocytosis with chronic myelomonocytic leukemia (SM-CMML). The teratoma and dysgerminoma differed by copy number aberrations via single nucleotide polymorphism (SNP) microarray, but were inclusive of the same c-KIT D816H point mutation (c.2446G>C) also identified in blood and bone marrow mast cells. These findings indicate not only a clonal origin of the GCT and hematologic malignancy, but also suggest a rare KIT mutation may be playing a fundamental role in malignancy development.

  18. Histological observation of germ cell development and discovery of spermatophores in ovoviviparous black rockfish ( Sebastes schlegeli Hilgendorf) in reproductive season

    NASA Astrophysics Data System (ADS)

    Feng, Junrong; Liu, Liming; Jiang, Haibin; Wang, Maojian; Du, Rongbin

    2014-10-01

    Black rockfish ( Sebastes schlegeli) is an important species for culture; however, its reproductive characteristics have not been fully documented. In this study, we investigated the morphology and developmental process of germ cells in this ovoviviparous rockfish in reproductive season (October 2011-November 2012) with histological methods. We found that the gonad of mature fish showed notable seasonal changes in developmental characteristics and morphological structure. The sperm cells matured during a period lasting from October to December, significantly earlier than the oocytes did. A large number of spermatozoa and other cells occurred in testis at different developmental stages. Vitellogenesis in oocytes began in October, and gestation appeared in April next year. Spermatophores were discovered for the first time in Sebastes, which assembled in testis, main sperm duct, oviduct and genital tract, as well as ovarian cavity in October and April. These organs may serve either as production or hiding places for spermatophores and spermatozoa which were stored and transported in form of spermatophores. Testicular degeneration started from the distal part of testis in April, with spermatophores assembled in degenerating testis and waiting for transportation. The copulation probably lasted for a long period, during which the spermatozoa were discharged in batches as spermatophores. These spermatophores were coated with sticky materials secreted from the interstitial areas of testis and the main sperm duct, then transported into ovary.

  19. Microfluidics co-culture systems for studying tooth innervation

    PubMed Central

    Pagella, Pierfrancesco; Neto, Estrela; Jiménez-Rojo, Lucia; Lamghari, Meriem; Mitsiadis, Thimios A.

    2014-01-01

    Innervation plays a key role in the development and homeostasis of organs and tissues of the orofacial complex. Among these structures, teeth are peculiar organs as they are not innervated until later stages of development. Furthermore, the implication of neurons in tooth initiation, morphogenesis and differentiation is still controversial. Co-cultures constitute a valuable method to investigate and manipulate the interactions of nerve fibers with their target organs in a controlled and isolated environment. Conventional co-cultures between neurons and their target tissues have already been performed, but these cultures do not offer optimal conditions that are closely mimicking the in vivo situation. Indeed, specific cell populations require different culture media in order to preserve their physiological properties. In this study we evaluate the usefulness of a microfluidics system for co-culturing mouse trigeminal ganglia and developing teeth. This device allows the application of specific media for the appropriate development of both neuronal and dental tissues. The results show that mouse trigeminal ganglia and teeth survive for long culture periods in this microfluidics system, and that teeth maintain the attractive or repulsive effect on trigeminal neurites that has been observed in vivo. Neurites are repealed when co-cultured with embryonic tooth germs, while postnatal teeth exert an attractive effect to trigeminal ganglia-derived neurons. In conclusion, microfluidics system devices provide a valuable tool for studying the behavior of neurons during the development of orofacial tissues and organs, faithfully imitating the in vivo situation. PMID:25202282

  20. Differential expression of cxcl-14 during eruptive movement of rat molar germs.

    PubMed

    Yoo, H I; Kang, J H; Yang, S Y; Yong, J H; Moon, J S; Kim, M S; Jung, J Y; Koh, J T; Kim, W J; Oh, W M; Lee, E J; Kim, S H

    2011-09-15

    Tooth eruption at the early postnatal period is strictly controlled by the molecules secreted mainly from follicular tissues, which recruit monocytes for osteoclast formation. In this study, it was hypothesized that different molecules can be expressed according to the stages of tooth eruption. Rat molar germs together with follicles were extracted and DD-PCR was performed from the root formation stage 2nd molars germs (after eruptive movement) and cap stage 3rd molar germs (before movement) at postnatal day 9. Cxcl-14, a potent chemoattractant, was detected as one of the differentially expressed molecules from DD-PCR. Its expression increased significantly at the root formation stage, compared with the cap or crown formation stage at both transcription and translation levels. The expression patterns of cxcl-14 were consistent with those of MCP-1 and CSF-1, and opposite to OPG. Immunofluorescence showed that cxcl-14 was localized in the dental follicular tissues only at the root formation stage overlaying the proximo-occlusal region of the molar germs. Many osteoclasts appeared on the surface of the alveolar bone which overlayed the occlusal region of the root formation stage 2nd molar germs and underwent resorption. Cxcl-14 expression was reduced considerably at both the translation and transcription levels by an alendronate treatment. These results suggest that cxcl-14 may be implicated in the formation of the eruptive pathway of tooth germs via osteoclastogenesis. Copyright © 2011 Wiley-Liss, Inc., A Wiley Company.

  1. A Reappraisal of Developing Permanent Tooth Length as an Estimate of Age in Human Immature Skeletal Remains.

    PubMed

    Cardoso, Hugo F V; Spake, Laure; Liversidge, Helen M

    2016-09-01

    This study expands on existing juvenile age prediction models from tooth length by increasing sample size and using classical calibration. A sample of 178 individuals from two European known sex and age skeletal samples was used to calculate prediction formulae for each tooth for each sex separately and combined. Prediction errors, residuals, and percentage of individuals whose real age fell within the 95% prediction interval were calculated. An ANCOVA was used to test sex and sample differences. Tooth length for age does not differ between the samples except for the canine and second premolar, and no statistically significant sex differences were detected. The least prediction error was found in the incisors and the first molar, and the highest prediction error was found in the third molar. Age prediction formulae provided here can be easily used in a variety of contexts where tooth length is measured from any isolated tooth.

  2. Ovarian Germ Cell Tumors Treatment

    MedlinePlus

    ... Tube, & Primary Peritoneal Cancer Screening Research Ovarian Germ Cell Tumors Treatment (PDQ®)–Patient Version General Information About Ovarian Germ Cell Tumors Go to Health Professional Version Key Points ...

  3. A report of an impacted primary maxillary central incisor tooth.

    PubMed

    Anthonappa, Robert P; Ongtengco, Kristine L; King, Nigel M

    2013-10-01

    Primary tooth impaction is a rare phenomenon when compared to permanent teeth impaction. The purpose of this report is to present a 5-year-old Chinese girl who exhibited impaction of tooth 51, its unusual consequence on the permanent successor tooth and its comprehensive management. Her parents revealed that at 6 months of age, the patient had fallen from her bed and struck her face on the floor; however, there were no teeth present in the oral cavity. The intraoral examinations identified a bony-like projection on the buccal aspect of the alveolus in the 51 region. Radiographic examination revealed that tooth 51 exhibited an unfavourable orientation, with the crown directed towards the palate. Therefore, the impacted tooth 51 was surgically removed, and two years later tooth 11 erupted into the oral cavity with an indentation on its incisal aspect, which resembled the crown of the primary teeth, thus giving the appearance of a tooth within a tooth or 'dens in dente'. Subsequently, enameloplasty and composite resin build-up was performed on tooth 11 for aesthetic reasons. It is very unusual to have the clinical crowns of both primary and permanent teeth in such close proximity within the alveolar bone, and the present case is a good example to emphasize that trauma to the primary teeth is of considerable importance due to the close proximity of the primary teeth to permanent tooth germs. © 2013 John Wiley & Sons A/S.

  4. Connexin channels in Schwann cells and the development of the X-linked form of Charcot-Marie-Tooth disease.

    PubMed

    Ressot, C; Bruzzone, R

    2000-04-01

    Charcot-Marie-Tooth disease comprises a group of genetically heterogenous disorders of the peripheral nervous system. The X-linked form of Charcot-Marie-Tooth (CMTX) is associated with mutations in the gene encoding the gap junction protein connexin32 (Cx32), which is expressed in Schwann cells. Immunocytochemical evidence suggests that Cx32 is localized to the incisures of Schmidt-Lanterman and the paranodes of myelinating Schwann cells, where it appears to form reflexive gap junctions. It is currently thought that this cytoplasmic continuity provides a much shorter diffusion pathway for the transport of ions, metabolites and second messenger molecules through intracellular channels between the adaxonal and peri-nuclear regions of Schwann cells, across the myelin sheath. This review summarizes our current understanding of the role of connexins in Schwann cells and focuses on the lessons for channel function and disease pathophysiology derived from the functional analysis of Cx32 mutations. One of the most intriguing aspects emerging from this work is that several mutations retain functional competence, although the mutated channels exhibit altered gating properties. This suggests that partial and/or selective disruption of the radial communication pathway formed by Cx32 is sufficient to cause a functional deficit and lead to the development of CMTX. The next challenge will be to define, at the molecular level, the sequence of events involved in the disease process. The presence of a group of functional mutations should help understand the cellular basis of CMTX, by allowing the identification of the specific molecules that need to be exchanged through Cx32 channels, but are excluded from the mutated ones.

  5. Development of germ-line-specific CRISPR-Cas9 systems to improve the production of heritable gene modifications in Arabidopsis.

    PubMed

    Mao, Yanfei; Zhang, Zhengjing; Feng, Zhengyan; Wei, Pengliang; Zhang, Hui; Botella, José Ramón; Zhu, Jian-Kang

    2016-02-01

    The Streptococcus-derived CRISPR/Cas9 system is being widely used to perform targeted gene modifications in plants. This customized endonuclease system has two components, the single-guide RNA (sgRNA) for target DNA recognition and the CRISPR-associated protein 9 (Cas9) for DNA cleavage. Ubiquitously expressed CRISPR/Cas9 systems (UC) generate targeted gene modifications with high efficiency but only those produced in reproductive cells are transmitted to the next generation. We report the design and characterization of a germ-line-specific Cas9 system (GSC) for Arabidopsis gene modification in male gametocytes, constructed using a SPOROCYTELESS (SPL) genomic expression cassette. Four loci in two endogenous genes were targeted by both systems for comparative analysis. Mutations generated by the GSC system were rare in T1 plants but were abundant (30%) in the T2 generation. The vast majority (70%) of the T2 mutant population generated using the UC system were chimeras while the newly developed GSC system produced only 29% chimeras, with 70% of the T2 mutants being heterozygous. Analysis of two loci in the T2 population showed that the abundance of heritable gene mutations was 37% higher in the GSC system compared to the UC system and the level of polymorphism of the mutations was also dramatically increased with the GSC system. Two additional systems based on germ-line-specific promoters (pDD45-GT and pLAT52-GT) were also tested, and one of them was capable of generating heritable homozygous T1 mutant plants. Our results suggest that future application of the described GSC system will facilitate the screening for targeted gene modifications, especially lethal mutations in the T2 population. © 2015 Society for Experimental Biology, Association of Applied Biologists and John Wiley & Sons Ltd.

  6. Identifying a novel role for X-prolyl aminopeptidase (Xpnpep) 2 in CrVI-induced adverse effects on germ cell nest breakdown and follicle development in rats.

    PubMed

    Banu, Sakhila K; Stanley, Jone A; Sivakumar, Kirthiram K; Arosh, Joe A; Barhoumi, Rola; Burghardt, Robert C

    2015-03-01

    Environmental exposure to endocrine-disrupting chemicals (EDCs) is one cause of premature ovarian failure (POF). Hexavalent chromium (CrVI) is a heavy metal EDC widely used in more than 50 industries, including chrome plating, welding, wood processing, and tanneries. Recent data from U.S. Environmental Protection Agency indicate increased levels of Cr in drinking water from several American cities, which potentially predispose residents to various health problems. Recently, we demonstrated that gestational exposure to CrVI caused POF in F1 offspring. The current study was performed to identify the molecular mechanism behind CrVI-induced POF. Pregnant rats were treated with 25 ppm of potassium dichromate from Gestational Day (GD) 9.5 to GD 14.5 through drinking water, and the fetuses were exposed to CrVI through transplacental transfer. Ovaries were removed from the fetuses or pups on Embryonic Day (ED) 15.5, ED 17.5, Postnatal Day (PND) 1, PND 4, or PND 25, and various analyses were performed. Results showed that gestational exposure to CrVI: 1) increased germ cell/oocyte apoptosis and advanced germ cell nest (GCN) breakdown; 2) increased X-prolyl aminopeptidase (Xpnpep) 2, a POF marker in humans, during GCN breakdown; 3) decreased Xpnpep2 during postnatal follicle development; and 4) increased colocalization of Xpnpep2 with Col3 and Col4. We also found that Xpnpep2 inversely regulated the expression of Col1, Col3, and Col4 in all the developmental stages studied. Thus, CrVI advanced GCN breakdown and increased follicle atresia in F1 female progeny by targeting Xpnpep2. © 2015 by the Society for the Study of Reproduction, Inc.

  7. Cadmium increases human fetal germ cell apoptosis.

    PubMed

    Angenard, Gaëlle; Muczynski, Vincent; Coffigny, Hervé; Pairault, Catherine; Duquenne, Clotilde; Frydman, René; Habert, René; Rouiller-Fabre, Virginie; Livera, Gabriel

    2010-03-01

    Cadmium (Cd) is a common environmental pollutant and a major constituent of tobacco smoke. Adverse effects of this heavy metal on reproductive function have been identified in adults; however, no studies have examined its effects on human reproductive organs during development. Using our previously developed organ culture system, we investigated the effects of cadmium chloride on human gonads at the beginning of fetal life, a critical stage in the development of reproductive function. Human fetal gonads were recovered during the first trimester (711 weeks postconception) and cultured with or without Cd. We used different concentrations of Cd and compared results with those obtained with mouse fetal gonads at similar stages. Cd, at concentrations as low as 1 microM, significantly decreased the germ cell density in human fetal ovaries. This correlated with an increase in germ cell apoptosis, but there was no effect on proliferation. Similarly, in the human fetal testis, Cd (1 microM) reduced germ cell number without affecting testosterone secretion. In mouse fetal gonads, Cd increased only female germ cell apoptosis. This is the first experimental demonstration that Cd, at low concentrations, alters the survival of male and female germ cells in humans. Considering data demonstrating extensive human exposure, we believe that current environmental levels of Cd could be deleterious to early gametogenesis.

  8. In Vivo Functional Requirement of the Mouse Ifitm1 Gene for Germ Cell Development, Interferon Mediated Immune Response and Somitogenesis

    PubMed Central

    Klymiuk, Ingeborg; Kenner, Lukas; Adler, Thure; Busch, Dirk H.; Boersma, Auke; Irmler, Martin; Gailus-Durner, Valérie; Fuchs, Helmut; Leitner, Nicole; Müller, Mathias; Kühn, Ralf; Schlederer, Michaela; Treise, Irina; de Angelis, Martin Hrabě; Beckers, Johannes

    2012-01-01

    The mammalian Interferon induced transmembrane protein 1 (Ifitm1) gene was originally identified as a member of a gene family highly inducible by type I and type II interferons. Based on expression analyses, it was suggested to be required for normal primordial germ cell migration. The knockdown of Ifitm1 in mouse embryos provided evidence for a role in somitogenesis. We generated the first targeted knockin allele of the Ifitm1 gene to systematically reassess all inferred functions. Sperm motility and the fertility of male and female mutant mice are as in wild type littermates. Embryonic somites and the adult vertebral column appear normal in homozygous Ifitm1 knockout mice, demonstrating that Ifitm1 is not essential for normal segmentation of the paraxial mesoderm. Proportions of leucocyte subsets, including granulocytes, monocytes, B-cells, T-cells, NK-cells, and NKT-cells, are unchanged in mutant mice. Based on a normal immune response to Listeria monocytogenes infection, there is no evidence for a dysfunction in downstream IFNγ signaling in Ifitm1 mutant mice. Expression from the Ifitm1 locus from E8.5 to E14.5 is highly dynamic. In contrast, in adult mice, Ifitm1 expression is highly restricted and strong in the bronchial epithelium. Intriguingly, IFITM1 is highly overexpressed in tumor epithelia cells of human squamous cell carcinomas and in adenocarcinomas of NSCLC patients. These analyses underline the general importance of targeted in vivo studies for the functional annotation of the mammalian genome. The first comprehensive description of the Ifitm1 expression pattern provides a rational basis for the further examination of Ifitm1 gene functions. Based on our data, the fact that IFITM1 can function as a negative regulator of cell proliferation, and because the gene maps to chromosome band 11p15.5, previously associated with NSCLC, it is likely that IFITM1 in man has a key role in tumor formation. PMID:23115618

  9. Expression of a nonmyristylated variant of the catalytic subunit of protein kinase A during male germ-cell development.

    PubMed

    Desseyn, J L; Burton, K A; McKnight, G S

    2000-06-06

    The catalytic subunits of protein kinase A are transcribed in all mouse tissues from two distinct genes that code for the Calpha and Cbeta isoforms. Alternative promoters exist for the Cbeta gene that are used in a tissue-specific fashion and give rise to variants that differ in their amino-terminal sequences. We have characterized an alternative promoter that is present in the first intron of the Calpha gene and is transcriptionally active in male germ cells. Transcription from this promoter is coincident with the appearance of pachytene spermatocytes and leads to a Calpha protein (Calpha2) that contains a distinctive 7 amino acid amino-terminus differing from the 14 amino acid amino-terminus of Calpha1. The Calpha2 protein does not contain the myristylation signal present on Calpha1 and migrates at a lower molecular weight on SDS/PAGE gels. By Western blotting, we estimate that most or all of the Calpha protein present in mature sperm is Calpha2. The amino-terminal sequence of Calpha2 is similar to that of ovine sperm C as previously reported [San Agustin, J. T., Leszyk, J. D., Nuwaysir, L. M. & Witman, G. B. (1998) J. Biol. Chem. 273, 24874-24883], and we show by cDNA cloning that human sperm also express a highly related Calpha2 homolog. The Calpha2 subunit forms holoenzymes with either RIIalpha or RIalpha, and both activate at the same concentration of cyclic nucleotide. Because protein kinase A is thought to play a pivotal role in sperm motility and capacitation, the distinctive biochemical properties of the unmyristylated Calpha2 may be essential for fertility in the male.

  10. AiGERM: A logic programming front end for GERM

    NASA Technical Reports Server (NTRS)

    Hashim, Safaa H.

    1990-01-01

    AiGerm (Artificially Intelligent Graphical Entity Relation Modeler) is a relational data base query and programming language front end for MCC (Mission Control Center)/STP's (Space Test Program) Germ (Graphical Entity Relational Modeling) system. It is intended as an add-on component of the Germ system to be used for navigating very large networks of information. It can also function as an expert system shell for prototyping knowledge-based systems. AiGerm provides an interface between the programming language and Germ.

  11. Comparison of tooth development stage of the maxillary anterior teeth before and after secondary alveolar bone graft: Unilateral cleft lip and alveolus vs unilateral cleft lip and palate.

    PubMed

    Park, Heon-Mook; Han, Dong-Hun; Baek, Seung-Hak

    2014-11-01

    To compare the effect of secondary alveolar bone graft (SABG) on the tooth development stage of the maxillary central incisor (MXCI) and maxillary canine (MXC) in terms of the severity of unilateral cleft. The subjects consisted of 50 boys with unilateral cleft lip and alveolus (UCLA) or unilateral cleft lip, alveolus, and palate (UCLP). The age- and sex-matched subjects were divided into group 1 (UCLA, n = 25; 9.3 ± 0.8 years old) and group 2 (UCLP, n = 25; 9.4 ± 0.6 years old). In panoramic radiographs taken 1 month before (T0) and 1 year after SABG (T1), tooth development stage was evaluated according to the Nolla developmental (ND) stage. A panoramic radiograph taken 3 years after SABG was used as a reference for the final root length of individual tooth. In groups 1 and 2, the ND stage of the MXCI did not exhibit differences between the cleft and non-cleft sides at T0 and T1, respectively. However, although the ND stage of the MXC of group 2 was delayed on the cleft side compared with the non-cleft side at T0 (P < .05), the MXC on the cleft side developed faster than that on the non-cleft side after SABG (P < .01). In terms of tooth development speed, group 2 showed a higher rate of faster developed MXCs on the cleft side compared with the non-cleft side after SABG than group 1 (36.0% vs 8.0%, P < .05). SABG performed at approximately 9 years of age might increase tooth development speed of MXC in patients with UCLP compared with patients with UCLA.

  12. Identity of M2A (D2-40) antigen and gp36 (Aggrus, T1A-2, podoplanin) in human developing testis, testicular carcinoma in situ and germ-cell tumours.

    PubMed

    Sonne, Si Brask; Herlihy, Amy S; Hoei-Hansen, Christina E; Nielsen, John E; Almstrup, Kristian; Skakkebaek, Niels E; Marks, Alexander; Leffers, Henrik; Rajpert-De Meyts, Ewa

    2006-08-01

    Testicular germ-cell tumours of young adults are derived from a pre-invasive intratubular lesion, carcinoma in situ (CIS). In a recent genome-wide gene expression screening using cDNA microarrays, we found PDPN over-expressed in CIS compared to normal adult testis. PDPN encodes podoplanin (Aggrus, human gp36, T1A-2), a transmembrane glycoprotein expressed in lymphatic endothelium and various solid tumours. To examine a potential role for PDPN in testicular neoplasms and during testicular development, we investigated its expression pattern during the development of human testis and in a series of testicular CIS, gonadoblastoma and overt germ-cell tumours. We established by RT-PCR and by immunohistochemistry with a gp36 antibody that PDPN mRNA and the protein product were expressed in testes with germ-cell neoplasms but not in the normal adult testis. We also found gp36 expression in early foetal gonocytes and immature Sertoli cells, similar to the expression pattern of M2A antigen, a previously identified marker for CIS and seminoma. This reinforced our previous proposal that M2A (D2-40) antigen was identical to gp36 (podoplanin, Aggrus, T1A-2). Our findings also suggest that podoplanin has a function in developing testis, most likely at the level of cell-cell interactions among pre-meiotic germ cells and immature Sertoli cells.

  13. Novel human mutation and CRISPR/Cas genome-edited mice reveal the importance of C-terminal domain of MSX1 in tooth and palate development

    PubMed Central

    Mitsui, Silvia Naomi; Yasue, Akihiro; Masuda, Kiyoshi; Naruto, Takuya; Minegishi, Yoshiyuki; Oyadomari, Seiichi; Noji, Sumihare; Imoto, Issei; Tanaka, Eiji

    2016-01-01

    Several mutations, located mainly in the MSX1 homeodomain, have been identified in non-syndromic tooth agenesis predominantly affecting premolars and third molars. We identified a novel frameshift mutation of the highly conserved C-terminal domain of MSX1, known as Msx homology domain 6 (MH6), in a Japanese family with non-syndromic tooth agenesis. To investigate the importance of MH6 in tooth development, Msx1 was targeted in mice with CRISPR/Cas system. Although heterozygous MH6 disruption did not alter craniofacial development, homozygous mice exhibited agenesis of lower incisors with or without cleft palate at E16.5. In addition, agenesis of the upper third molars and the lower second and third molars were observed in 4-week-old mutant mice. Although the upper second molars were present, they were abnormally small. These results suggest that the C-terminal domain of MSX1 is important for tooth and palate development, and demonstrate that that CRISPR/Cas system can be used as a tool to assess causality of human disorders in vivo and to study the importance of conserved domains in genes. PMID:27917906

  14. Novel human mutation and CRISPR/Cas genome-edited mice reveal the importance of C-terminal domain of MSX1 in tooth and palate development.

    PubMed

    Mitsui, Silvia Naomi; Yasue, Akihiro; Masuda, Kiyoshi; Naruto, Takuya; Minegishi, Yoshiyuki; Oyadomari, Seiichi; Noji, Sumihare; Imoto, Issei; Tanaka, Eiji

    2016-12-05

    Several mutations, located mainly in the MSX1 homeodomain, have been identified in non-syndromic tooth agenesis predominantly affecting premolars and third molars. We identified a novel frameshift mutation of the highly conserved C-terminal domain of MSX1, known as Msx homology domain 6 (MH6), in a Japanese family with non-syndromic tooth agenesis. To investigate the importance of MH6 in tooth development, Msx1 was targeted in mice with CRISPR/Cas system. Although heterozygous MH6 disruption did not alter craniofacial development, homozygous mice exhibited agenesis of lower incisors with or without cleft palate at E16.5. In addition, agenesis of the upper third molars and the lower second and third molars were observed in 4-week-old mutant mice. Although the upper second molars were present, they were abnormally small. These results suggest that the C-terminal domain of MSX1 is important for tooth and palate development, and demonstrate that that CRISPR/Cas system can be used as a tool to assess causality of human disorders in vivo and to study the importance of conserved domains in genes.

  15. Black carp vasa identifies embryonic and gonadal germ cells.

    PubMed

    Xue, Ting; Yu, Miao; Pan, Qihua; Wang, Yizhou; Fang, Jian; Li, Lingyu; Deng, Yu; Chen, Kai; Wang, Qian; Chen, Tiansheng

    2017-07-01

    Identification of molecular markers is an essential step in the study of germ cells. Vasa is an RNA helicase and a well-known germ cell marker that plays a crucial role in germ cell development. Here, we identified the Vasa homolog termed Mpvasa as the first germ cell marker in black carp (Mylopharyngodon piceus). First, a 2819-bp full-length Mpvasa complementary DNA (cDNA) was cloned by PCR using degenerated primers of conserved sequences and gene-specific primers. The Mpvasa cDNA sequence encodes a 637-amino acid protein that contains eight conserved characteristic motifs of the DEAD box protein family, and shares high identity to grass carp (81%) and zebrafish (74%) vasa homologs. Second, Mpvasa expression was restricted to the gonad in adulthood by RT-PCR and Western blot analysis. The dynamic patterns of temporal-spatial expression of Mpvasa during gametogenesis were examined by in situ hybridization, and Mpvasa transcripts were strictly detected in gonadal germ cells throughout oogenesis, predominantly in immature oocytes (stage I, II, and III oocytes). Third, Mpvasa transcripts were highly detected in unfertilized eggs and early embryos, and the signal indicated a dynamic migration of the primordial germ cells during embryogenesis, suggesting that Mpvasa transcripts were maternally inherited and specifically distributed in germ cells. Taken together, these results demonstrated that Mpvasa is an applicable molecular marker for identification of gonadal and embryonic germ cells, which facilitates the isolation and utilization of germ cells in black carp.

  16. Dynamic Analysis of the Expression of the TGFβ/SMAD2 Pathway and CCN2/CTGF during Early Steps of Tooth Development

    PubMed Central

    Pacheco, Marcos S.; Reis, Alice H.; Aguiar, Diego P.; Lyons, Karen M.; Abreu, José G.

    2009-01-01

    Background/Aims CCN2 is present during tooth development. However, the relationship between CCN2 and the transforming growth factor β (TGFβ)/SMAD2/3 signaling cascade during early stages of tooth development is unclear. Here, we compare the expression of CCN2 and TGFβ/SMAD2/3 components during tooth development, and analyze the functioning of TGFβ/SMAD2/3 in wild-type (WT) and Ccn2 null (Ccn2−/−) mice. Methods Coronal sections of mice on embryonic day (E)11.5, E12.5, E13.5, E14.5 and E18.5 from WT and Ccn2−/− were immunoreacted to detect CCN2 and components of the TGFβ signaling pathway and assayed for 5′-bromo-2′-deoxyuridine immunolabeling and proliferating cell nuclear antigen immunostaining. Results CCN2 and TGFβ signaling components such as TGFβ1, TGFβ receptor II, SMADs2/3 and SMAD4 were expressed in inducer tissues during early stages of tooth development. Proliferation analysis in these areas showed that epithelial cells proliferate less than mesenchymal cells from E11.5 to E13.5, while at E14.5 they proliferate more than