Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.1.3.1 (alkaline phosphatase)
47,916 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Rat incisors grow continuously throughout life. Producing a variety of dental epithelial cells is performed by stem cells located in the cervical loop of the incisor apex. To study the mechanisms for cell differentiation, we established a dental epithelial cell line (HAT-7) originating from a cervical loop epithelium of a rat incisor. Immunochemical studies showed that HAT-7 produced the cells expressing amelogenin, ameloblastin, or alkaline phosphatase (ALP). To illustrate a role of Notch signaling in the determinant of the cell fate, we examined expression patterns of Notch1 and Jagged1 in HAT-7 density dependently. At lower cell density, Notch1- or Jagged1-expressing cells were not seen. However, when they were fully confluent, cells began to express Notch1 or Jagged1 strongly. Some ALP-positive cells were almost consistent with Notch1-expressing cells but not Jagged1-expressing cells. These results suggested that the determinant of direction of differentiation was associated with Notch signaling pathway.
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PMID:Establishment of dental epithelial cell line (HAT-7) and the cell differentiation dependent on Notch signaling pathway. 1248 91

We examined the effects of basic fibroblast growth factor (FGF-2) on cultured lower molar tooth germ at the differentiative (bell) stage. Although FGF-2 has been detected in odontogenesis, its roles in biological activities, such as cell proliferation, differentiation and extracellular matrix mineralization are unclear. We assayed mRNA levels of the differentiation markers, dentine sialophosphoprotein (DSPP), amelogenin and alkaline phosphatase (ALP) using reverse transcription-polymerase chain reaction (RT-PCR), and histological methods. Tooth germs dissected from 17-day-old embryonic mice were cultured for 4 days with either recombinant human FGF-2 or specific antisense phosphorothioate oligodeoxynucleotide (antisense ODN) for FGF-2. Exogenous FGF-2 decreased the gene expression of differentiation markers in molars at the bell stage. Abrogation of endogenous FGF-2 by antisense ODN increased the gene expression of differentiation markers, and also significantly enhanced enamel and dentine formation. This histological change was recovered by adding exogeneous FGF-2. These findings suggest that FGF-2 at the bell stage regulates cell differentiation and matrix secretion.
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PMID:Fgf-2 regulates enamel and dentine formation in mouse tooth germ. 1295 98

Dental epithelial progenitor cells differentiate into various cell types during development of tooth germs. To study this mechanism, we produced immortalized dental epithelial progenitor cells derived from the cervical-loop epithelium of a rat lower incisor. The expression patterns of cytokeratin 14, nerve growth factor receptor p75, amelogenin, Notch2, and alkaline phosphatase were examined by immunohistochemistry in both lower and higher cell densities. The patterns of each were compared in the dental epithelium of rat lower incisors. The results demonstrated that these cells could produce ameloblast lineage cells, stratum intermedium cells, stellate reticulum, and outer enamel epithelium. Furthermore, fibroblast growth factor 10 stimulated proliferation of dental progenitor cells and subsequently increased the number of cells expressing alkaline phosphatase. These results suggest that fibroblast growth factor 10 plays a role in coupling mitogenesis of the cervical-loop cells and the production of stratum intermedium cells in rat incisors.
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PMID:Characterization of dental epithelial progenitor cells derived from cervical-loop epithelium in a rat lower incisor. 1474 50

Osteoblast differentiation and extracellular matrix production are pivotal processes for implant osseointegration or bone tissue engineering. We hypothesized that a biomimetic coating on titanium surfaces, consisting of apatite and amelogenin, would promote such processes. Human Embryonic Palatal Mesenchymal pre-osteoblasts were used as a model for the evaluation of cell adhesion and spreading patterns, as well as mRNA expression of certain osteoblastic gene products. Real-time PCR showed significant (p < 0.05) increase in expression of type I collagen, alkaline phosphatase, and osteocalcin from cells grown on titanium with an apatite/amelogenin composite, as compared with that from cells grown on a pure titanium or apatite coating only. Osteocalcin expression was specifically stimulated by amelogenin added to the culture media. Enhanced attachment and cell spreading were also observed. The biomimetic coating promoting cell adhesion and osteoblast differentiation may have great potential for future dental and biomedical applications.
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PMID:Apatite/amelogenin coating on titanium promotes osteogenic gene expression. 1624 44

Numerous studies have demonstrated the effect of shear stress on osteoblasts, but its effect on odontogenic cells has never been reported. In this study, we focused on the effect of shear stress on facilitating tissue-engineered odontogenesis by dissociated single cells. Cells were harvested from the porcine third molar tooth at the early stage of crown formation, and the isolated heterogeneous cells were seeded on a biodegradable polyglycolic acid fiber mesh. Then, cell-polymer constructs with and without exposure to shear stress were evaluated by in vitro and in vivo studies. In in vitro studies, the expression of both epithelial and mesenchymal odontogenic-related mRNAs was significantly enhanced by shear stress for 2 h. At 12 h after exposure to shear stress, the expression of amelogenin, bone sialoprotein and vimentin protein was significantly enhanced compared with that of control. Moreover, after 7 days, alkaline phosphatase activity exhibited a significant increase without any significant effect on cell proliferation in vitro. In vivo, enamel and dentin tissues formed after 15 weeks of in vivo implantation in constructs exposure to in vitro shear stress for 12 h. Such was not the case in controls. We concluded that shear stress facilitates odontogenic cell differentiation in vitro as well as the process of tooth tissue engineering in vivo.
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PMID:Shear stress facilitates tissue-engineered odontogenesis. 1646 51

The purpose of this study was to identify the periodontal regeneration factors of enamel protein extracts that induce cementum and bone regeneration in vivo. Cementum regeneration, one aspect of periodontal ligament regeneration, was examined using a buccal dehiscence model of dogs. Enamel matrix protein fractions were prepared from developing porcine incisors. Cementum-regeneration activity was found to reside in a protein aggregate composed of amelogenins and sheath proteins extracted from newly formed secretory enamel. Cementum-regeneration activity was not observed in protein fractions containing only amelogenin or its derivatives. The sheath proteins were purified to homogeneity and tested for alkaline phosphatase (ALP)-inducing activity on human periodontal ligament (HPDL) cells. The induction of ALP was observed following application of the 17-kDa sheath protein but not of the lower-molecular-weight sheath proteins. Although transforming growth factor-beta1 also shows ALP-inducing activity, contamination with growth factors was excluded because synthetic peptides (based on the sheath protein's sequence) also showed ALP-inducing activity. The 17-kDa sheath protein showed both cytodifferentiation and cementum-regeneration activity, but it is unclear whether its cementum-regeneration activity is derived from its ALP-inducing activity on HPDL cells.
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PMID:Porcine sheath proteins show periodontal ligament regeneration activity. 1667 88

Amelogenins are a group of heterogenous proteins first identified in developing tooth enamel and reported to be present in odontoblasts. The objective of this study was to elucidate the expression and function of amelogenins in the human dentin-pulp complex. Developing human tooth buds were immunostained for amelogenin, and mRNA was detected by in situ hybridization. The effects of recombinant amelogenins on pulp and papilla cell proliferation were measured by Brd U immunoassay, and differentiation was monitored by alkaline phosphatase expression. Amelogenin protein was found in the forming dentin matrix, and amelogenin mRNA was localized in the dentin, presumably in the odontoblast processes. Proliferation of papilla cells was enhanced by recombinant human amelogenin rH72 (LRAP+ exon 4), while pulp cells responded to both rH72 and rH58 (LRAP), with no effect by rH174. These studies suggest that odontoblasts actively synthesize and secrete amelogenin protein during human tooth development, and that low-molecular-weight amelogenins can enhance pulp cell proliferation.
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PMID:Amelogenins in human developing and mature dental pulp. 1693 63

The organic material of our teeth consists of collagens and a number of calcium-binding phosphoproteins. Six of these phosphoproteins have recently been grouped in the family of the SIBLINGs (small integrin-binding ligand, N-linked glycoproteins), namely osteopontin, bone sialoprotein, dentin matrix protein (DMP1), dentin sialophosphoprotein (DSPP), matrix extracellular phosphoglycoprotein (MEPE) and enamelin. We prepared a cDNA library from rat incisors in order to identify the genes involved in tooth formation. The library was screened by subtractive hybridization with two probes; one specific for teeth, the other for bone. We found that the vast majority of the clones from our library were expressed at similar levels in bone and teeth, demonstrating the close relationship of the two tissues. Only 7% of all the clones were expressed in a tooth-specific fashion. These included clones for the enamel proteins; amelotin, amelogenin, ameloblastin and enamelin; for the dentin proteins DSPP and DMP1; and for the intermediate filament protein cytokeratin 13. Several typical bone proteins, including collagen I, osteocalcin, alkaline phosphatase and FATSO, were also expressed at significantly higher levels in teeth than in bone, probably due to the extreme growth rate of rat incisors. The amino acid sequence of rat amelotin showed 62% identity with the sequence from humans. It was expressed considerably later than the other enamel proteins, suggesting that amelotin may serve a function different from those of amelogenin, ameloblastin and enamelin.
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PMID:Expression of phosphoproteins and amelotin in teeth. 1714 47

Enamel matrix derivative (EMD) is widely considered useful to promote tissue regeneration during periodontal treatment. It has been reported that the main constituent of EMD is amelogenin and that the BMP-like and TGF-beta-like activity of EMD promotes osteogenesis. However, it remains unclear whether those activities are dependent on amelogenin or another growth factor contained in EMD. We performed two-dimensional SDS-PAGE analysis of EMD, as well as Western blot analyses using anti-amelogenin, anti-BMP2/4, and anti-TGF-beta1 antibodies, and amino acid sequencing. Our results revealed that a large number of splicing forms of amelogenin, BMP2/4, and other unknown molecules were involved in EMD, though TGF-beta1 was not. In addition, we have evaluated intracellular signaling of ERK1/2 and Smad1/5/8, binding potential and alkaline phosphatase activity and have explored the potential regulatory relationship between amelogenin and BMP. Amelogenin bound to BMP2 as well as heparin/heparan sulfate. Thus, it was suggested that BMP2/4 carried over in EMD during processing promote binding activity and phosphorylate Smad1/5/8 in osteoblasts. On the other hand, amelogenin did not phosphorylate Smad1/5/8, but rather ERK1/2. Further, high-density amelogenin reduced the inhibition of alkaline phosphatase activity by noggin, though amelogenin did not have antagonistic properties against BMP. Together with the above findings, our findings suggest that the BMP2/4 contaminated during the purification process of EMD because of the avidity of amelogenin plays an important role in signaling pathway of calcification.
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PMID:Amelogenin binds to both heparan sulfate and bone morphogenetic protein 2 and pharmacologically suppresses the effect of noggin. 1851 7

The selective serotonin re-uptake inhibitor (SSRI) fluoxetine is widely used in the treatment of depression in children and fertile women, but its effect on developing tissues has been sparsely investigated. The aim of this study was to investigate if enamel organs and ameloblast-derived cells express serotonin receptors that are affected by peripherally circulating serotonin or fluoxetine. Using RT-PCR and western blot analysis we found that enamel organs from 3-d-old mice and ameloblast-like cells (LS8 cells) express functional serotonin receptors, the rate-limiting enzyme in serotonin synthesis (Thp1), as well as the serotonin transporter (5HTT), indicating that enamel organs and ameloblasts are able to respond to serotonin and regulate serotonin availability. Fluoxetine and serotonin enhanced the alkaline phosphatase activity in the cell culture medium from cultured LS8 cells, whereas the expression of enamelin (Enam), amelogenin (Amel), and matrix metalloproteinase-20 (MMP-20) were all significantly down-regulated. The secretion of vascular endothelial growth factor (VEGF), monocyte chemotactic protein 1 (MCP-1), and interferon-inducible protein 10 (IP-10) was also reduced compared with controls. In conclusion, enamel organs and ameloblast-like cells express functional serotonin receptors. Reduced transcription of enamel proteins and secretion of vascular factors may indicate possible adverse effects of fluoxetine on amelogenesis.
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PMID:Serotonin and fluoxetine receptors are expressed in enamel organs and LS8 cells and modulate gene expression in LS8 cells. 2108 17


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