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Gary E. Wise - One of the best experts on this subject based on the ideXlab platform.
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chronological gene expression of parathyroid hormone related protein pthrp in the Stellate reticulum of the rat implications for tooth eruption
Archives of Oral Biology, 2007Co-Authors: Shaomian Yao, Fenghui Pan, Gary E. WiseAbstract:Abstract Objective Tooth eruption is a localized event that requires the expression of certain molecules at precise times to regulate bone resorption and bone formation. Parathyroid hormone-related protein (PTHrP) may be one of those molecules. Although PTHrP is produced in the Stellate reticulum (SR) of the tooth and exerts its effect on the adjacent dental follicle, its expression pattern in the SR is unknown. Thus, it was the objectives of this study to determine the chronology of expression of PTHrP, and then to determine its effect on vascular endothelial growth factor (VEGF) expression for osteoclastogenesis and on bone morphogenetic protein-2 (BMP-2) for bone growth. Design Laser capture microdissection and RT-PCR were used to determine the chronological expression of PTHrP in vivo. In vitro, dental follicle cells were incubated with PTHrP and RT-PCR was conducted to determine its effect on VEGF and BMP-2 gene expression. Results PTHrP was maximally expressed at day 7 postnatally in the SR with the level of expression still high at day 9. In vitro, PTHrP upregulated VEGF120 and VEGF164 expression after 4 h of incubation with a maximum effect at 6 h. PTHrP upregulated BMP-2 gene expression with a maximal effect at 2 h. Conclusions Because the secondary burst of osteoclastogenesis needed for eruption occurs around day 10, it is possible that PTHrP is stimulating this osteoclastogenesis by upregulating VEGF. Concurrently, the upregulation of BMP-2 by PTHrP may stimulate bone growth at the base of the bony crypt to promote eruption.
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Chronological gene expression of parathyroid hormone-related protein (PTHrP) in the Stellate reticulum of the rat—Implications for tooth eruption
Archives of Oral Biology, 2007Co-Authors: Shaomian Yao, Fenghui Pan, Gary E. WiseAbstract:Abstract Objective Tooth eruption is a localized event that requires the expression of certain molecules at precise times to regulate bone resorption and bone formation. Parathyroid hormone-related protein (PTHrP) may be one of those molecules. Although PTHrP is produced in the Stellate reticulum (SR) of the tooth and exerts its effect on the adjacent dental follicle, its expression pattern in the SR is unknown. Thus, it was the objectives of this study to determine the chronology of expression of PTHrP, and then to determine its effect on vascular endothelial growth factor (VEGF) expression for osteoclastogenesis and on bone morphogenetic protein-2 (BMP-2) for bone growth. Design Laser capture microdissection and RT-PCR were used to determine the chronological expression of PTHrP in vivo. In vitro, dental follicle cells were incubated with PTHrP and RT-PCR was conducted to determine its effect on VEGF and BMP-2 gene expression. Results PTHrP was maximally expressed at day 7 postnatally in the SR with the level of expression still high at day 9. In vitro, PTHrP upregulated VEGF120 and VEGF164 expression after 4 h of incubation with a maximum effect at 6 h. PTHrP upregulated BMP-2 gene expression with a maximal effect at 2 h. Conclusions Because the secondary burst of osteoclastogenesis needed for eruption occurs around day 10, it is possible that PTHrP is stimulating this osteoclastogenesis by upregulating VEGF. Concurrently, the upregulation of BMP-2 by PTHrP may stimulate bone growth at the base of the bony crypt to promote eruption.
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Effect of epidermal growth factor on expression of transforming growth factor-β1 mRNA in Stellate reticulum cells of rat mandibular molars
Developmental Dynamics, 1993Co-Authors: Fan Lin, Gary E. WiseAbstract:Cultured Stellate reticulum cells isolated from rat mandibular molars respond to incubation in EGF by increasing their level of expression of TGF-beta 1 mRNA. Northern blots showed that incubation in EGF for 6 hours stimulated over a two-fold increase in TGF-beta 1 mRNA in the cells. In contrast, incubating the cells in TGF-beta 1 did not enhance the expression of TGF-beta 1 mRNA in the cells, indicating that TGF-beta 1 does not have an autocrine effect on these cells. Immunocytochemistry showed that EGF receptor was present on the surface of many but not all of the cultured Stellate reticulum cells. Because EGF does stimulate premature eruption of teeth, it is possible that its effect on the Stellate reticulum region of the enamel organ would be to stimulate synthesis of TGF-beta 1 mRNA which, in turn, could lead to increased synthesis of TGF-beta 1 by these cells. The cells do contain the TGF-beta 1 protein as revealed by immunocytostaining. The newly synthesized TGF-beta 1 may exert its effect on the adjacent dental follicle to either initiate the onset of the cellular events of tooth eruption or to increase the secretion of extracellular matrix proteins by the follicle for formation of the periodontal ligament.
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Isolation of granule proteins from cells of the dental follicle and Stellate reticulum of rat mandibular molars
Archives of Oral Biology, 1992Co-Authors: Fan Lin, Wei Fan, Gary E. WiseAbstract:The presence of a dental follicle is required for eruption of teeth of limited eruption but it is uncertain if any molecules indigenous to the follicle regulate this eruption. However, electron-dense granules of unknown composition and function are present in the fibroblasts of the dental follicle of rat molars, as well as the adjacent Stellate reticulum, before and during tooth eruption. Here the granules have been isolated; two proteins, of 167 and 200 kDa, have been determined by biochemical and immunological methods to be major components of the granules.
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Granule proteins of the dental follicle and Stellate reticulum inhibit tooth eruption and eyelid opening in postnatal rats.
Archives of Oral Biology, 1992Co-Authors: Fan Lin, Wei Fan, Gary E. WiseAbstract:Electron-dense granules within cells of the dental follicle and Stellate reticulum of rat mandibular molars can be isolated; their major components are 167 and 200 kDa proteins. Injecting these granule proteins into postnatal rats results in a delay of incisor eruption and eyelid separation. These inhibitory effects were most pronounced with the 167 kDa protein (a delay of 3 days in incisor eruption and of 2 days in eyelid opening) and were opposite to the stimulatory effects of epidermal growth factor. Thus, these granules may play an inhibitory part in tooth eruption.
Takashi Saku - One of the best experts on this subject based on the ideXlab platform.
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Reciprocal expressions between α-dystroglycan and integrin β1, perlecan receptors, in the murine enamel organ development.
Gene Expression Patterns, 2013Co-Authors: Hiroko Ida-yonemochi, Hidemitsu Harada, Hayato Ohshima, Takashi SakuAbstract:Signals of perlecan, an extracellular matrix molecule, which accumulates within the intercellular spaces of the Stellate reticulum of the enamel organ, are mediated by at least two receptors, dystroglycan (DG) and integrin β1, in a case-dependent manner in various events in embryogenesis and pathogenesis. This study aims to understand the expression profiles of these two perlecan receptors at both protein and gene levels in murine enamel organ development. Before birth, α-DG was immunolocalized in Stellate reticulum cells, in which perlecan was colocalized, while integrin β1 was mainly distributed in the peripheral enamel organ cells as well as the dental mesenchymal cells. On and after postnatal Day 1, the expression of α-DG was dramatically decreased in the Stellate reticulum, while integrin β1 was enhanced around blood vessels within the enamel organ. Furthermore, biosyntheses of α-DG and integrin β1 by dental epithelial and pulp mesenchymal cells were confirmed in vitro by using immunofluorescence and reverse-transcriptase polymerase chain reaction. The results suggest that DG is a perlecan receptor that specifically functions in the Stellate reticulum of the embryonic stage, but that dental epithelial and mesenchymal cells are maturated by capturing perlecan signals differentially through integrin β1.
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Differential expression profiles between α-dystroglycan and integrin β1 in ameloblastoma: two possible perlecan signalling pathways for cellular growth and differentiation.
Histopathology, 2011Co-Authors: Hiroko Ida-yonemochi, Shahidul Ahsan, Takashi SakuAbstract:Ida-Yonemochi H, Ahsan M S & Saku T (2011) Histopathology58, 234–245 Differential expression profiles between α-dystroglycan and integrin β1 in ameloblastoma: two possible perlecan signalling pathways for cellular growth and differentiation Aims: Intercellular deposition of perlecan, an extracellular matrix molecule, results in characteristic Stellate reticulum-like structures in ameloblastomas. The aims of this study were to elucidate which types of perlecan receptors function within any particular type of tissue architecture of ameloblastoma. Methods and results: Protein and gene expression profiles for α-dystroglycan and integrin β1 were examined comparatively with those of their ligands in ameloblastoma using surgical specimens and cells in primary culture. In the follicular-type tumour cell foci, α-dystroglycan was localized uniformly over the Stellate reticulum-like cells, while integrin β1 was restricted mainly to peripheral cells facing the stroma with the interface of the basement membrane, which was also rich in perlecan. In the plexiform-type, mRNA and protein signals for α-dystroglycan were enhanced in the periphery of tumour cell foci, especially in their invading fronts. Integrin β1 was also immunolocalized in the basal cell zone, which was considered to be the proliferation centre of ameloblastoma cells. Furthermore, biosynthesis of α-dystroglycan and integrin β1 by ameloblastoma cells was confirmed in vitro using immunofluorescence and reverse transcriptase–polymerase chain reaction. Conclusions: Ameloblastoma cells proliferate and are differentiated by capturing perlecan differentially with α-dystroglycan and integrin β1, respectively.
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Heparanase, heparan sulfate and perlecan distribution along with the vascular penetration during Stellate reticulum retraction in the mouse enamel organ.
Archives of Oral Biology, 2010Co-Authors: Hiroko Ida-yonemochi, Motowo Nakajima, Takashi SakuAbstract:Abstract Objective Immunohistochemical and gene expression profiles of heparanase were determined in murine molar tooth germs from their embryonic to postnatal stages, paying special attention to neovascularization within the enamel organ, which is poorly vascularized before birth. Design Protein and gene expression profiles of heparanase, heparan sulfate (HS), vascular endothelial growth factor (VEGF), transforming growth factor-β1 (TGF-β1), and perlecan were comparatively examined by immunohistochemistry and in-situ hybridization, respectively, in mouse mandibular molar tooth germs from embryonic day 11.5 to postnatal day 6. At the same time, their mRNA expression levels were also confirmed by reverse transcriptase-polymerase chain reaction using laser-captured microdissection of enamel organ tissues. Results Stellate reticulum cells highly expressed perlecan but only slightly expressed heparanase and HS in their embryonic days. On and after postnatal day 1, the expressions of heparanase became dramatically higher in the Stellate reticulum, while HS disappeared leaving the immunopositivity for perlecan core protein. Immunohistochemically, HS was enhanced around blood vessels which were newly formed after birth within the enamel organs, whose volume was also regressive. Similar expression patterns were obtained for VEGF and TGF-β1. Conclusions Such synchronized expression modes among the HS metabolism-related molecules suggested that heparanase plays an important role in degradation of HS chains, which is closely related to vascular penetration into the Stellate reticulum, which may be one of the driving forces for the postnatal regression of the enamel organ.
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Perlecan, a Heparan Sulfate Proteoglycan, Is a Major Constituent of the Intraepithelial Stroma Functioning in Tooth Morphogenesis
Journal of Oral Biosciences, 2007Co-Authors: Hiroko Ida-yonemochi, Takashi SakuAbstract:Abstract Perlecan, a heparan sulfate proteoglycan, is one of the major basement membrane macromolecules, plays an important role in cellular growth, differentiation, adhesion,, motility by its interaction with growth factors, cytokines. Recently, perlecan has been localized within the epithelial space in various pathophysiological conditions. As the intraepithelial accumulation of perlecan results in widening of the intercellular space, the most characteristic example of such phenomena is the Stellate reticulum of the enamel organ of tooth germs, whose structure, function have been largely unknown. Stellate reticulumlike structures are also found in pathological conditions such as ameloblastoma or oral epithelial dysplasia. The biosynthesis of perlecan has been demonstrated in those epithelial cells,, such peculiar Stellate reticulum appearances are shown to be due to intercellular deposits of over-expressed perlecan. However, when perlecan is transgened into mouse epithelial tissue using the keratin 5 promoter, the tooth cannot be formed normally. Thus, a constant over-expression of perlecan interferes with normal development. The time schedule of the intraepithelial expression of perlecan seems to be controlled critically in the process of odontogenesis. In this review article, we address the current views on the structure, function of perlecan acting in the intraepithelial stromal space, with special attention to its role in tooth morphogenesis.
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Perlecan, a basement membrane-type heparan sulfate proteoglycan, in the enamel organ: its intraepithelial localization in the Stellate reticulum.
Journal of Histochemistry & Cytochemistry, 2005Co-Authors: Hiroko Ida-yonemochi, Kazufumi Ohshiro, Wael Swelam, Hamdy Metwaly, Takashi SakuAbstract:SUMMARY The localization and biosynthesis of perlecan, a basement membrane–type heparan sulfate proteoglycan, were studied in developing tooth germs by using murine molars in neonatal and postnatal stages and primary cultured cells of the enamel organ and dental papilla to demonstrate the role of perlecan in normal odontogenesis. Perlecan was immunolocalized mainly in the intercellular spaces of the enamel organ as well as in the dental papilla/pulp or in the dental follicle. By in situ hybridization, mRNA signals for perlecan core protein were intensely demonstrated in the cytoplasm of Stellate reticulum cells and in dental papilla/pulp cells, including odontoblasts and fibroblastic cells in the dental follicle. Furthermore, the in vitro biosyntheses of perlecan core protein by the enamel organ and dental papilla/pulp cells were confirmed by immunofluorescence, immunoprecipitation, and reverse transcriptase–polymerase chain reaction. The results indicate that perlecan is synthesized by the dental epithelial cells and is accumulated in their intercellular spaces to form the characteristic Stellate reticulum, whose function is still unknown. (J Histochem Cytochem 53:763–772, 2005)
Irma Thesleff - One of the best experts on this subject based on the ideXlab platform.
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Observations on continuously growing roots of the sloth and the K14‐Eda transgenic mice indicate that epithelial stem cells can give rise to both the ameloblast and root epithelium cell lineage creating distinct tooth patterns
Evolution & Development, 2008Co-Authors: Mark Tummers, Irma ThesleffAbstract:Root development is traditionally associated with the formation of Hertwig's epithelial root sheath (HERS), whose fragments give rise to the epithelial cell rests of Malassez (ERM). The HERS is formed by depletion of the core of Stellate reticulum cells, the putative stem cells, in the cervical loop, leaving only a double layer of the basal epithelium with limited growth capacity. The continuously growing incisor of the rodent is subdivided into a crown analog half on the labial side, with a cervical loop containing a large core of Stellate reticulum, and its progeny gives rise to enamel producing. The lingual side is known as the root analog and gives rise to ERM. We show that the lingual cervical loop contains a small core of Stellate reticulum cells and suggest that it acts as a functional stem cell niche. Similarly we show that continuously growing roots represented by the sloth molar and K14-Eda transgenic incisor maintain a cervical loop with a small core of Stellate reticulum cells around the entire circumference of the tooth and do not form a HERS, and still give rise to ERM. We propose that HERS is not a necessary structure to initiate root formation. Moreover, we conclude that crown vs. root formation, i.e. the production of enamel vs. cementum, and the differentiation of the epithelial cells into ameloblasts vs. ERM, can be regulated independently from the regulation of stem cell maintenance. This developmental flexibility may underlie the developmental and evolutionary diversity in tooth patterning.
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Observations on continuously growing roots of the sloth and the K14‐Eda transgenic mice indicate that epithelial stem cells can give rise to both the ameloblast and root epithelium cell lineage creating distinct tooth patterns
Evolution & Development, 2008Co-Authors: Mark Tummers, Irma ThesleffAbstract:Current address and address at time of work for both authors: Institute of Biotechnology, P.O. Box 56, FIN-00014 University of Helsinki, Finland. SUMMARY Root development is traditionally associated with the formation of Hertwig’s epithelial root sheath (HERS), whose fragments give rise to the epithelial cell rests of Malassez (ERM). The HERS is formed by depletion of the core of Stellate reticulum cells, the putative stem cells, in the cervical loop, leaving only a double layer of the basal epithelium with limited growth capacity. The continuously growing incisor of the rodent is subdivided into a crown analog half on the labial side, with a cervical loop containing a large core of Stellate reticulum, and its progeny gives rise to enamel producing. The lingual side is known as the root analog and gives rise to ERM. We show that the lingual cervical loop contains a small core of Stellate reticulum cells and suggest that it acts as a functional stem cell niche. Similarly we show that continuously growing roots represented by the sloth molar and K14-Eda transgenic incisor maintain a cervical loop with a small core of Stellate reticulum cells around the entire circumference of the tooth and do not form a HERS, and still give rise to ERM. We propose that HERS is not a necessary structure to initiate root formation. Moreover, we conclude that crown vs. root formation, i.e. the production of enamel vs. cementum, and the differentiation of the epithelial cells into ameloblasts vs. ERM, can be regulated independently from the regulation of stem cell maintenance. This developmental flexibility may underlie the developmental and evolutionary diversity in tooth patterning.
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Localization of Putative Stem Cells in Dental Epithelium and Their Association with Notch and Fgf Signaling
Journal of Cell Biology, 1999Co-Authors: Hidemitsu Harada, Han-sung Jung, Päivi Kettunen, Tuija Mustonen, Y. Alan Wang, Hidemitsu Harada, Irma ThesleffAbstract:The continuously growing mouse incisor is an excellent model to analyze the mechanisms for stem cell lineage. We designed an organ culture method for the apical end of the incisor and analyzed the epithelial cell lineage by 5-bromo-2′-deoxyuridine and DiI labeling. Our results indicate that stem cells reside in the cervical loop epithelium consisting of a central core of Stellate reticulum cells surrounded by a layer of basal epithelial cells, and that they give rise to transit-amplifying progeny differentiating into enamel forming ameloblasts. We identified slowly dividing cells among the Notch1-expressing Stellate reticulum cells in specific locations near the basal epithelial cells expressing lunatic fringe, a secretory molecule modulating Notch signaling. It is known from tissue recombination studies that in the mouse incisor the mesenchyme regulates the continuous growth of epithelium. Expression of Fgf-3 and Fgf-10 were restricted to the mesenchyme underlying the basal epithelial cells and the transit-amplifying cells expressing their receptors Fgfr1b and Fgfr2b. When FGF-10 protein was applied with beads on the cultured cervical loop epithelium it stimulated cell proliferation as well as expression of lunatic fringe. We present a model in which FGF signaling from the mesenchyme regulates the Notch pathway in dental epithelial stem cells via stimulation of lunatic fringe expression and, thereby, has a central role in coupling the mitogenesis and fate decision of stem cells.
Hiroko Ida-yonemochi - One of the best experts on this subject based on the ideXlab platform.
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Reciprocal expressions between α-dystroglycan and integrin β1, perlecan receptors, in the murine enamel organ development.
Gene Expression Patterns, 2013Co-Authors: Hiroko Ida-yonemochi, Hidemitsu Harada, Hayato Ohshima, Takashi SakuAbstract:Signals of perlecan, an extracellular matrix molecule, which accumulates within the intercellular spaces of the Stellate reticulum of the enamel organ, are mediated by at least two receptors, dystroglycan (DG) and integrin β1, in a case-dependent manner in various events in embryogenesis and pathogenesis. This study aims to understand the expression profiles of these two perlecan receptors at both protein and gene levels in murine enamel organ development. Before birth, α-DG was immunolocalized in Stellate reticulum cells, in which perlecan was colocalized, while integrin β1 was mainly distributed in the peripheral enamel organ cells as well as the dental mesenchymal cells. On and after postnatal Day 1, the expression of α-DG was dramatically decreased in the Stellate reticulum, while integrin β1 was enhanced around blood vessels within the enamel organ. Furthermore, biosyntheses of α-DG and integrin β1 by dental epithelial and pulp mesenchymal cells were confirmed in vitro by using immunofluorescence and reverse-transcriptase polymerase chain reaction. The results suggest that DG is a perlecan receptor that specifically functions in the Stellate reticulum of the embryonic stage, but that dental epithelial and mesenchymal cells are maturated by capturing perlecan signals differentially through integrin β1.
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Differential expression profiles between α-dystroglycan and integrin β1 in ameloblastoma: two possible perlecan signalling pathways for cellular growth and differentiation.
Histopathology, 2011Co-Authors: Hiroko Ida-yonemochi, Shahidul Ahsan, Takashi SakuAbstract:Ida-Yonemochi H, Ahsan M S & Saku T (2011) Histopathology58, 234–245 Differential expression profiles between α-dystroglycan and integrin β1 in ameloblastoma: two possible perlecan signalling pathways for cellular growth and differentiation Aims: Intercellular deposition of perlecan, an extracellular matrix molecule, results in characteristic Stellate reticulum-like structures in ameloblastomas. The aims of this study were to elucidate which types of perlecan receptors function within any particular type of tissue architecture of ameloblastoma. Methods and results: Protein and gene expression profiles for α-dystroglycan and integrin β1 were examined comparatively with those of their ligands in ameloblastoma using surgical specimens and cells in primary culture. In the follicular-type tumour cell foci, α-dystroglycan was localized uniformly over the Stellate reticulum-like cells, while integrin β1 was restricted mainly to peripheral cells facing the stroma with the interface of the basement membrane, which was also rich in perlecan. In the plexiform-type, mRNA and protein signals for α-dystroglycan were enhanced in the periphery of tumour cell foci, especially in their invading fronts. Integrin β1 was also immunolocalized in the basal cell zone, which was considered to be the proliferation centre of ameloblastoma cells. Furthermore, biosynthesis of α-dystroglycan and integrin β1 by ameloblastoma cells was confirmed in vitro using immunofluorescence and reverse transcriptase–polymerase chain reaction. Conclusions: Ameloblastoma cells proliferate and are differentiated by capturing perlecan differentially with α-dystroglycan and integrin β1, respectively.
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Heparanase, heparan sulfate and perlecan distribution along with the vascular penetration during Stellate reticulum retraction in the mouse enamel organ.
Archives of Oral Biology, 2010Co-Authors: Hiroko Ida-yonemochi, Motowo Nakajima, Takashi SakuAbstract:Abstract Objective Immunohistochemical and gene expression profiles of heparanase were determined in murine molar tooth germs from their embryonic to postnatal stages, paying special attention to neovascularization within the enamel organ, which is poorly vascularized before birth. Design Protein and gene expression profiles of heparanase, heparan sulfate (HS), vascular endothelial growth factor (VEGF), transforming growth factor-β1 (TGF-β1), and perlecan were comparatively examined by immunohistochemistry and in-situ hybridization, respectively, in mouse mandibular molar tooth germs from embryonic day 11.5 to postnatal day 6. At the same time, their mRNA expression levels were also confirmed by reverse transcriptase-polymerase chain reaction using laser-captured microdissection of enamel organ tissues. Results Stellate reticulum cells highly expressed perlecan but only slightly expressed heparanase and HS in their embryonic days. On and after postnatal day 1, the expressions of heparanase became dramatically higher in the Stellate reticulum, while HS disappeared leaving the immunopositivity for perlecan core protein. Immunohistochemically, HS was enhanced around blood vessels which were newly formed after birth within the enamel organs, whose volume was also regressive. Similar expression patterns were obtained for VEGF and TGF-β1. Conclusions Such synchronized expression modes among the HS metabolism-related molecules suggested that heparanase plays an important role in degradation of HS chains, which is closely related to vascular penetration into the Stellate reticulum, which may be one of the driving forces for the postnatal regression of the enamel organ.
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Perlecan, a Heparan Sulfate Proteoglycan, Is a Major Constituent of the Intraepithelial Stroma Functioning in Tooth Morphogenesis
Journal of Oral Biosciences, 2007Co-Authors: Hiroko Ida-yonemochi, Takashi SakuAbstract:Abstract Perlecan, a heparan sulfate proteoglycan, is one of the major basement membrane macromolecules, plays an important role in cellular growth, differentiation, adhesion,, motility by its interaction with growth factors, cytokines. Recently, perlecan has been localized within the epithelial space in various pathophysiological conditions. As the intraepithelial accumulation of perlecan results in widening of the intercellular space, the most characteristic example of such phenomena is the Stellate reticulum of the enamel organ of tooth germs, whose structure, function have been largely unknown. Stellate reticulumlike structures are also found in pathological conditions such as ameloblastoma or oral epithelial dysplasia. The biosynthesis of perlecan has been demonstrated in those epithelial cells,, such peculiar Stellate reticulum appearances are shown to be due to intercellular deposits of over-expressed perlecan. However, when perlecan is transgened into mouse epithelial tissue using the keratin 5 promoter, the tooth cannot be formed normally. Thus, a constant over-expression of perlecan interferes with normal development. The time schedule of the intraepithelial expression of perlecan seems to be controlled critically in the process of odontogenesis. In this review article, we address the current views on the structure, function of perlecan acting in the intraepithelial stromal space, with special attention to its role in tooth morphogenesis.
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Perlecan, a basement membrane-type heparan sulfate proteoglycan, in the enamel organ: its intraepithelial localization in the Stellate reticulum.
Journal of Histochemistry & Cytochemistry, 2005Co-Authors: Hiroko Ida-yonemochi, Kazufumi Ohshiro, Wael Swelam, Hamdy Metwaly, Takashi SakuAbstract:SUMMARY The localization and biosynthesis of perlecan, a basement membrane–type heparan sulfate proteoglycan, were studied in developing tooth germs by using murine molars in neonatal and postnatal stages and primary cultured cells of the enamel organ and dental papilla to demonstrate the role of perlecan in normal odontogenesis. Perlecan was immunolocalized mainly in the intercellular spaces of the enamel organ as well as in the dental papilla/pulp or in the dental follicle. By in situ hybridization, mRNA signals for perlecan core protein were intensely demonstrated in the cytoplasm of Stellate reticulum cells and in dental papilla/pulp cells, including odontoblasts and fibroblastic cells in the dental follicle. Furthermore, the in vitro biosyntheses of perlecan core protein by the enamel organ and dental papilla/pulp cells were confirmed by immunofluorescence, immunoprecipitation, and reverse transcriptase–polymerase chain reaction. The results indicate that perlecan is synthesized by the dental epithelial cells and is accumulated in their intercellular spaces to form the characteristic Stellate reticulum, whose function is still unknown. (J Histochem Cytochem 53:763–772, 2005)
Enrico Gherlone - One of the best experts on this subject based on the ideXlab platform.
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Vascular endothelial growth factor and nitric oxide synthase expression in human tooth germ development.
Journal of biological regulators and homeostatic agents, 2016Co-Authors: Filiberto Mastrangelo, M. T. Sberna, Lucia Tettamanti, Giuseppe Cantatore, Angelo Tagliabue, Enrico GherloneAbstract: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.
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Vascular endothelial growth factor behavior in different stages of tooth germ development.
Minerva stomatologica, 2016Co-Authors: Filiberto Mastrangelo, M. T. Sberna, Lucia Tettamanti, Giuseppe Cantatore, Angelo Tagliabue, Raffaele Vinci, Giovanni Iaderosa, Enrico GherloneAbstract:BACKGROUND 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. METHODS 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. RESULTS 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. CONCLUSIONS 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.