Authorship：Lead author,　Corresponding author   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.jds.2023.11.019

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Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

DOI： 10.1016/j.jds.2024.05.028

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Publishing type：Research paper (scientific journal)   Publisher：MDPI AG  

Periodontal ligament-associated protein 1 (PLAP-1), also known as Asporin, is an extracellular matrix protein expressed in the periodontal ligament and plays a crucial role in periodontal tissue homeostasis. Our previous research demonstrated that PLAP-1 may inhibit TLR2/4-mediated inflammatory responses, thereby exerting a protective function against periodontitis. However, the precise roles of PLAP-1 in the periodontal ligament (PDL) and its relationship to periodontitis have not been fully explored. In this study, we employed PLAP-1 knockout mice to investigate its roles and contributions to PDL tissue and function in a ligature-induced periodontitis model. Mandibular bone samples were collected from 10-week-old male C57BL/6 (WT) and PLAP-1 knockout (KO) mice. These samples were analyzed through micro-computed tomography (μCT) scanning, hematoxylin and eosin (HE) staining, picrosirius red staining, and fluorescence immunostaining using antibodies targeting extracellular matrix proteins. Additionally, the structure of the PDL collagen fibrils was examined using transmission electron microscopy (TEM). We also conducted tooth extraction and ligature-induced periodontitis models using both wild-type and PLAP-1 KO mice. PLAP-1 KO mice did not exhibit any changes in alveolar bone resorption up to the age of 10 weeks, but they did display an enlarged PDL space, as confirmed by μCT and histological analyses. Fluorescence immunostaining revealed increased expression of extracellular matrix proteins, including Col3, BGN, and DCN, in the PDL tissues of PLAP-1 KO mice. TEM analysis demonstrated an increase in collagen diameter within the PDL of PLAP-1 KO mice. In line with these findings, the maximum stress required for tooth extraction was significantly lower in PLAP-1 KO mice in the tooth extraction model compared to WT mice (13.89 N ± 1.34 and 16.51 N ± 1.31, respectively). In the ligature-induced periodontitis model, PLAP-1 knockout resulted in highly severe alveolar bone resorption, with a higher number of collagen fiber bundle tears and significantly more osteoclasts in the periodontium. Our results demonstrate that mice lacking PLAP-1/Asporin show alteration of periodontal ligament structures and acceleration of bone loss in periodontitis. This underscores the significant role of PLAP-1 in maintaining collagen fibrils in the PDL and suggests the potential of PLAP-1 as a therapeutic target for periodontal diseases.

DOI： 10.3390/ijms242115989

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DOI： 10.1016/j.jds.2023.09.027

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Authorship：Lead author,　Corresponding author   Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

Abstract

Dental pulp stem cells (DPSC) usually remain quiescent in the dental pulp tissue; however, once the dental pulp tissue is injured, DPSCs potently proliferate and migrate into the injury microenvironment and contribute to immuno-modulation and tissue repair. However, the key molecules that physiologically support the potent proliferation and migration of DPSCs have not been revealed. In this study, we searched publicly available transcriptome raw data sets, which contain comparable (i.e., equivalently cultured) DPSC and mesenchymal stem cell data. Three data sets were extracted from the Gene Expression Omnibus database and then processed and analyzed. MXRA5 was identified as the predominant DPSC-enriched gene associated with the extracellular matrix. MXRA5 is detected in human dental pulp tissues. Loss of MXRA5 drastically decreases the proliferation and migration of DSPCs, concomitantly with reduced expression of the genes associated with the cell cycle and microtubules. In addition to the known full-length isoform of MXRA5, a novel splice variant of MXRA5 was cloned in DPSCs. Recombinant MXRA5 coded by the novel splice variant potently induced the haptotaxis migration of DPSCs, which was inhibited by microtubule inhibitors. Collectively, MXRA5 is a key extracellular matrix protein in dental pulp tissue for maintaining the proliferation and migration of DPSCs.

DOI： 10.1038/s41598-023-42684-z

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Authorship：Lead author,　Corresponding author   Language：Japanese   Publishing type：Research paper (scientific journal)  

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Due to their multi-differentiation potential, periodontal ligament fibroblasts (PDLF) play pivotal roles in periodontal tissue regeneration in vivo. Several in vitro studies have suggested that PDLFs can transmit mechanical stress into favorable basic cellular functions. However, the application of mechanical force for periodontal regeneration therapy is not expected to exhibit an effective prognosis since mechanical forces, such as traumatic occlusion, also exacerbate periodontal tissue degeneration and loss. Herein, we established a standardized murine periodontal regeneration model and evaluated the regeneration process associated with cementum remodeling. By administering a kinase inhibitor of YAP/TAZ suppressor molecules, such as large tumor suppressor homolog 1/2 (LATS1/2), we found that the activation of YAP/TAZ, a key downstream effector of mechanical signals, accelerated periodontal tissue regeneration due to the activation of PDLF cell proliferation. Mechanistically, among six kinds of MAP4Ks previously reported as upstream kinases that suppressed YAP/TAZ transcriptional activity through LATS1/2 in various types of cells, MAP4K4 was identified as the predominant MAP4K in PDLF and contributed to cell proliferation and differentiation depending on its kinase activity. Ultimately, pharmacological activation of YAP/TAZ by inhibiting upstream inhibitory kinase in PDLFs is a valuable strategy for improving the clinical outcomes of periodontal regeneration therapies.

DOI： 10.3390/ijms24020970

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

Periodontitis is characterized by irreversible destruction of periodontal tissue. At present, the accepted etiology of periodontitis is based on a three-factor theory including pathogenic bacteria, host factors, and acquired factors. Periodontitis development usually takes a decade or longer and is therefore called chronic periodontitis (CP). To search for genetic factors associated with CP, several genome-wide association study (GWAS) analyses were conducted; however, polymorphisms associated with CP have not been identified. Epigenetics, on the other hand, involves acquired transcriptional regulatory mechanisms due to reversibly altered chromatin accessibility. Epigenetic status is a condition specific to each tissue and cell, mostly determined by the responses of host cells to stimulations by local factors, like bacterial inflammation, and systemic factors such as nutrition status, metabolic diseases, and health conditions. Significantly, epigenetic status has been linked with the onset and progression of several acquired diseases. Thus, epigenetic factors in periodontal tissues are attractive targets for periodontitis diagnosis and treatments. In this review, we introduce accumulating evidence to reveal the epigenetic background effects related to periodontitis caused by genetic factors, systemic diseases, and local environmental factors, such as smoking, and clarify the underlying mechanisms by which epigenetic alteration influences the susceptibility of periodontitis.

DOI： 10.1016/j.jdsr.2022.06.001

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Authorship：Corresponding author   Publishing type：Research paper (scientific journal)   Publisher：SAGE Publications  

Enforced enrichment of the active promoter marks trimethylation of histone H3 lysine 4 (H3K4me3) and acetylation of histone H3 lysine 27 (H3K27ac) by inhibiting histone demethylases and deacetylases is positively associated with hard tissue formation through the induction of osteo/odontogenic differentiation. However, the key endogenous epigenetic modulator of odontoblasts to regulate the expression of genes coding dentin extracellular matrix (ECM) proteins has not been identified. We focused on nuclear factor (NF)–κB inhibitor ζ (IκBζ), which was originally identified as the transcriptional regulator of NF-κB and recently regarded as the NF-κB–independent epigenetic modulator, and found that IκBζ null mice exhibit a thicker dentin width and narrower pulp chamber, with aged mice having more marked phenotypes. At 6 mo of age, dentin fluorescent labeling revealed significantly accelerated dentin synthesis in the incisors of IκBζ null mice. In the molars of IκBζ null mice, marked tertiary dentin formation adjacent to the pulp horn was observed. Mechanistically, the expression of COL1A2 and COL1A1 collagen genes increased more in the odontoblast-rich fraction of IκBζ null mice than in wild type in vivo, similar to human odontoblast-like cells transfected with small interfering RNA for IκBζ compared with cells transfected with control siRNA in vitro. Furthermore, the direct binding of IκBζ to the COL1A2 promoter suppressed COL1A2 expression and the local active chromatin status marked by H3K4me3. Based on whole-genome identification of H3K4me3 enrichment, ECM and ECM organization–related gene loci were selectively activated by the knockdown of IκBζ, which consistently resulted in the upregulation of these genes. Collectively, this study suggested that IκBζ is the key negative regulator of dentin formation in odontoblasts by inhibiting dentin ECM- and ECM organization–related gene expression through an altered local chromatin status marked by H3K4me3. Therefore, IκBζ is a potential target for epigenetically improving the clinical outcomes of dentin regeneration therapies such as pulp capping.

DOI： 10.1177/00220345221075968

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Frontiers Media SA  

Cementum resorption, unlike bone resorption, is clinically known to occur only with limited pathological stimuli, such as trauma, orthodontic forces, and large apical periodontitis; however, the molecular mechanisms that control osteoclast formation on the cementum surface remain unclear. In this study, we focused on extracellular vesicles (EVs) secreted by cementoblasts and analyzed their effects on osteoclast differentiation. EVs were extracted from the conditioned medium (CM) of the mouse cementoblast cell line OCCM-30. Transmission electron microscopy (TEM) analysis confirmed the presence of EVs with a diameter of approximately 50–200 nm. The effect of the EVs on osteoclast differentiation was examined using the mouse osteoclast progenitor cell line RAW 264.7 with recombinant receptor activator of nuclear factor (NF)-κB ligand (rRANKL) stimulation. EVs enhanced the formation of tartrate-resistant acid phosphatase (TRAP) activity-positive cells upon rRANKL stimulation. EVs also enhanced the induction of osteoclast-associated gene and protein expression in this condition, as determined by real-time PCR and Western blotting, respectively. On the other hand, no enhancing effect of EVs was observed without rRANKL stimulation. A Western blot analysis revealed no expression of receptor activator of NF-κB ligand (RANKL) in EVs themselves. The effect on rRANKL-induced osteoclast differentiation was examined using the CM of cementoblasts in terms of TRAP activity-positive cell formation and osteoclast-associated gene expression. The conditioned medium partly inhibited rRANKL-induced osteoclast differentiation and almost completely suppressed its enhancing effect by EVs. These results indicate that cementoblasts secreted EVs, which enhanced RANKL-induced osteoclast differentiation, and simultaneously produced soluble factors that neutralized this enhancing effect of EVs, implicating this balance in the regulation of cementum absorption. A more detailed understanding of this crosstalk between cementoblasts and osteoclasts will contribute to the development of new therapies for pathological root resorption.

DOI： 10.3389/fphys.2022.825596

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Publishing type：Research paper (scientific journal)   Publisher：Public Library of Science (PLoS)  

Amelogenins, major extra cellular matrix proteins of developing tooth enamel, are predominantly expressed by ameloblasts and play significant roles in the formation of enamel. Recently, amelogenin has been detected in various epithelial and mesenchymal tissues, implicating that it might have distinct functions in various tissues. We have previously reported that leucine rich amelogenin peptide (LRAP), one of the alternate splice forms of amelogenin, regulates receptor activator of NF-kappa B ligand (RANKL) expression in cementoblast/periodontal ligament cells, suggesting that the amelogenins, especially LRAP, might function as a signaling molecule in bone metabolism. The objective of this study was to identify and define LRAP functions in bone turnover. We engineered transgenic (TgLRAP) mice using a murine 2.3kb α1(I)-collagen promoter to drive expression of a transgene consisting of LRAP, an internal ribosome entry site (IRES) and enhanced green fluorescent protein (EGFP) to study functions of LRAP in bone formation and resorption. Calvarial cell cultures from the TgLRAP mice showed increased alkaline phosphatase (ALP) activity and increased formation of mineralized nodules compared to the cells derived from wild-type (WT) mice. The TgLRAP calvarial cells also showed an inhibitory effect on osteoclastogenesis <italic>in vitro</italic>. Gene expression comparison by quantitative polymerase chain reaction (Q-PCR) in calvarial cells indicated that bone formation makers such as <italic>Runx2</italic>, <italic>Alp</italic>, and <italic>osteocalcin</italic> were increased in TgLRAP compared to the WT cells. Meanwhile, <italic>Rankl</italic> expression was decreased in the TgLRAP cells <italic>in vitro</italic>. The ovariectomized (OVX) TgLRAP mice resisted bone loss induced by ovariectomy resulting in higher bone mineral density in comparison to OVX WT mice. The quantitative analysis of calcein intakes indicated that the ovariectomy resulted in increased bone formation in both WT and TgLRAP mice; OVX TgLRAP appeared to show the most remarkably increased bone formation. The parameters for bone resorption in tissue sections showed increased number of osteoclasts in OVX WT, but not in OVX TgLRAP over that of sham operated WT or TgLRAP mice, supporting the observed bone phenotypes in OVX mice. This is the first report identifying that LRAP, one of the amelogenin splice variants, affects bone turnover <italic>in vivo</italic>.

DOI： 10.1371/journal.pone.0259966

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The periodontal ligament is a soft connective tissue embedded between the alveolar bone and cementum, the surface hard tissue of teeth. Periodontal ligament fibroblasts (PDLF) actively express osteo/cementogenic genes, which contribute to periodontal tissue homeostasis. However, the key factors maintaining the osteo/cementogenic abilities of PDLF remain unclear. We herein demonstrated that PPARγ was expressed by in vivo periodontal ligament tissue and its distribution pattern correlated with alkaline phosphate enzyme activity. The knockdown of PPARγ markedly reduced the osteo/cementogenic abilities of PDLF in vitro, whereas PPARγ agonists exerted the opposite effects. PPARγ was required to maintain the acetylation status of H3K9 and H3K27, active chromatin markers, and the supplementation of acetyl-CoA, a donor of histone acetylation, restored PPARγ knockdown-induced decreases in the osteo/cementogenic abilities of PDLF. An RNA-seq/ChIP-seq combined analysis identified four osteogenic transcripts, RUNX2, SULF2, RCAN2, and RGMA, in the PPARγ-dependent active chromatin region marked by H3K27ac. Furthermore, RUNX2-binding sites were selectively enriched in the PPARγ-dependent active chromatin region. Collectively, these results identified PPARγ as the key transcriptional factor maintaining the osteo/cementogenic abilities of PDLF and revealed that global H3K27ac modifications play a role in the comprehensive osteo/cementogenic transcriptional alterations mediated by PPARγ.

DOI： 10.3390/ijms22168646

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Publishing type：Research paper (scientific journal)   Publisher：Frontiers Media {SA}  

<jats:p>Loeys–Dietz syndrome (LDS) is a syndromic connective tissue disorder caused by a heterozygous missense mutation in genes that encode transforming growth factor (TGF)-β receptor (<jats:italic>TGFBR</jats:italic>) <jats:italic>1</jats:italic> and <jats:italic>2</jats:italic>. We encountered a patient with LDS, who had severe periodontal tissue destruction indicative of aggressive periodontitis. The patient had a missense mutation in the glycine and serine-rich domain of <jats:italic>TGFBR1</jats:italic> exon 3. This G-to-T mutation at base 563 converted glycine to valine. We established an LDS model knock-in mouse that recapitulated the LDS phenotype. Homozygosity of the mutation caused embryonic lethality and heterozygous knock-in mice showed distorted and ruptured elastic fibers in the aorta at 24 weeks of age and died earlier than wildtype (WT) mice. We stimulated mouse embryonic fibroblasts (MEFs) from the knock-in mouse with TGF-β and examined their responses. The knock-in MEFs showed downregulated <jats:italic>Serpine 1</jats:italic> mRNA expression and phosphorylation of Smad2 to TGF-β compared with WT MEFs. To clarify the influence of TGF-β signaling abnormalities on the pathogenesis or progression of periodontitis, we performed pathomolecular analysis of the knock-in mouse. There were no structural differences in periodontal tissues between WT and LDS model mice at 6 or 24 weeks of age. Micro-computed tomography revealed no significant difference in alveolar bone resorption between WT and knock-in mice at 6 or 24 weeks of age. However, TGF-β-related gene expression was increased significantly in periodontal tissues of the knock-in mouse compared with WT mice. Next, we assessed a mouse periodontitis model in which periodontal bone loss was induced by oral inoculation with the bacterial strain <jats:italic>Porphyromonas gingivalis</jats:italic> W83. After inoculation, we collected alveolar bone and carried out morphometric analysis. <jats:italic>P. gingivalis</jats:italic>-induced alveolar bone loss was significantly greater in LDS model mice than in WT mice. Peritoneal macrophages isolated from <jats:italic>Tgfbr1<jats:sup><jats:italic>G</jats:italic>188V/+</jats:sup></jats:italic> mice showed upregulation of inflammatory cytokine mRNA expression induced by <jats:italic>P. gingivalis</jats:italic> lipopolysaccharide compared with WT macrophages. In this study, we established an LDS mouse model and demonstrated that LDS model mice had elevated susceptibility to <jats:italic>P. gingivalis</jats:italic>-induced periodontitis, probably through TGF-β signal dysfunction. This suggests that TGF-β signaling abnormalities accelerate the pathogenesis or progression of periodontitis.</jats:p>

DOI： 10.3389/fphys.2021.715687

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Accumulating evidence suggests that specific non-coding RNAs exist in many types of malignant tissues, and are involved in cancer invasion and metastasis. However, little is known about the precise roles of non-coding RNAs in squamous cell carcinoma (SQCC) invasion and migration. Recently, the dentin matrix protein-1 (DMP-1) gene locus was identified as a transcriptionally active site in squamous cell carcinoma (SQCC) tissue and cells. However, it is unclear whether RNA associated with cell migration exist at the DMP-1 gene locus in SQCC cells. We identified a novel promoter-associated non-coding RNA in the antisense strand of DMP-1 gene locus, promoter-associated non-coding RNA (panRNA)-DMP-1, by the RACE method in SQCC cells and tissues, and characterized the functions of panRNA-DMP-1 in EGF-driven SQCC cell migration. The inhibition of endogenous panRNA-DMP-1 expression by specific siRNAs and exogenous over-expression of panRNA-DMP-1 resulted in increased and suppressed cellular migration toward EGF in SQCC cells, respectively, and nuclear expression of panRNA-DMP-1 was induced by EGF stimulation. Mechanistically, suppression of panRNA-DMP-1 expression increased EGFR nuclear localization upon EGF treatment and nuclear panRNA-DMP-1 physically interacted with EGFR, which was confirmed by RNA immunoprecipitation assay using a bacteriophage-delivered PP7 RNA labeling system. Furthermore, co-immunoprecipitation assay revealed that suppression of panRNA-DMP-1 stabilized EGFR interaction with STAT3, a known co-transcription factors of EGFR, to induce migratory properties in many cancer cells. Based on these findings, panRNA-DMP-1 is an EGFR-associating RNA that inhibits the EGF-induced migratory properties of SQCC possibly by regulating EGFR nuclear localization and EGFR binding to STAT3.

DOI： 10.1007/s11010-020-04046-5

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

<title>Abstract</title>Apical periodontitis (AP) is an acute or chronic inflammatory disease caused by complex interactions between infected root canal and host immune system. It results in the induction of inflammatory mediators such as chemokines and cytokines leading to periapical tissue destruction. To understand the molecular pathogenesis of AP, we have investigated inflammatory-related genes that regulate AP development. We found here that macrophage-derived CXCL9, which acts through CXCR3, is recruited by progressed AP. The inhibition of CXCL9 by a CXCR3 antagonist reduced the lesion size in a mouse AP model with decreasing IL-1β, IL-6 and TNFα expression. The treatment of peritoneal macrophages with CXCL9 and LPS induced the transmigration and upregulation of osteoclastogenic cytokines such as IL-1β, IL-6 and matrix metalloprotease 2, a marker of activated macrophages. This suggests that the CXCL9-CXCR3 axis plays a crucial role in the development of AP, mediated by the migration and activation of macrophages for periapical tissue destruction. Our data thus show that CXCL9 regulates the functions of macrophages which contribute to AP pathogenesis, and that blocking CXCL9 suppresses AP progression. Knowledge of the principal factors involved in the progression of AP, and the identification of related inflammatory markers, may help to establish new therapeutic strategies.

DOI： 10.1038/s41598-021-82167-7

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The spread of root canal infection to surrounding periodontal tissue through accessory root canals reduces the success rate of endodontic treatment. In this case, cone-beam computed tomography revealed a lesion (4 mm from the apex) resulting from an accessory root canal of the maxillary left central incisor. First, non-surgical endodontic treatment was conducted but the sinus tract remained. Surgical preparation of the root cavity was then conducted to remove potentially infected dentin surrounding the accessory root canal. The cavity was filled and the foramen was sealed with resin containing bioactive surface pre-reacted glass (S-PRG) filler. The photopolymerized resin was then contoured and polished. In combination with subsequent supportive non-surgical endodontic treatment, a good clinical outcome with the disappearance of the sinus tract and clinical symptoms such as discomfort and pressure pain and the regeneration of the alveolar bone hanging over the cavity was obtained. In this case, the good clinical outcome may have been due to the dentin-adhesive property and durability of the pre-adhesive system and composite resin. The better biocompatibility of S-PRG fillers presumably facilitated periodontal tissue healing.

DOI： 10.3390/dj8040131

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Pro-inflammatory cytokines prevent bone regeneration in vivo and activation of nuclear factor-κB (NF-κB) signaling has been proposed to lead to suppression of bone morphogenetic protein (BMP)-induced osteogenesis via direct binding of p65 to Smad4 in vitro. Application of a small nuclear acidic protein (MTI-II) and its delivered peptide, MPAID (MTI-II peptide anti-inflammatory drug) has been described to elicit therapeutic potential via strong anti-inflammatory action following the physical association of MTI-II and MPAID with p65. However, it is unclear whether MTI-II attenuates tumor necrosis factor (TNF)-α inhibition of BMP-induced osteogenesis. Herein, we found that TNF-α-mediated suppression of responses associated with BMP4-induced osteogenesis, including expression of the osteocalcin encoding gene Ocn, Smad binding element (SBE)-dependent luciferase activity, alkaline phosphatase activity, and alizarin red S staining were largely restored by MTI-II and MPAID in MC3T3-E1 cells. Mechanistically, MTI-II and MPAID did not inhibit nuclear translocation of p65 or disassociate Smad4 from p65. Further, results from chromatin immunoprecipitation (ChIP) analyses revealed that Smad4 enrichment in cells over-expressing MTI-II and treated with TNF-α was equivalent to that in cells without TNF-α treatment. Alternatively, Smad4 enrichment was considerably decreased following TNF-α treatment in control cells. Moreover, p65 enrichment in the Id-1 promoter SBE was detected only when cells over-expressing MTI-II were stimulated with TNF-α. Overall, our study concludes that MTI-II restored TNF-α-inhibited suppression of BMP-Smad-induced osteogenic differentiation by enhancing accessibility of the Smad4-p65 complex to the SBE rather than by liberating Smad4 from p65.

DOI： 10.1007/s11010-020-03734-6

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© 2019 Elsevier Ltd Objective: The objective of this study was to investigate the effects of dentin phosphoprotein (DPP) on lipopolysaccharide-induced inflammatory responses of macrophages in vitro. Design: Wildtype and mutant recombinant dentin phosphoprotein (rDPP) proteins were generated using a mammalian expression system. Macrophages, phorbol 12-myristate 13-acetate-differentiated THP-1 cells, were stimulated with lipopolysaccharide in the absence or presence of rDPP proteins. After the 24-hr incubation, the inflammatory gene expression levels were examined by quantitative reverse-transcription polymerase chain reaction and the amount of secreted TNF-α protein was evaluated by enzyme-linked immunosorbent assay. Furthermore, the subcellular localization of exogenously added rDPP was examined by immunocytochemistry, and the direct binding of rDPP to lipopolysaccharide was quantified by solid-phase binding assay. Results: rDPP dose-dependently reduced the expression of lipopolysaccharide-induced inflammatory genes, such as TNFα, IL-1β, and IL-8, and TNF-α protein secretion from the macrophages. Furthermore, mutant rDPP having a shortened serine/aspartic acid-rich repeats (SDrr) was also able to inhibit lipopolysaccharide-induced inflammatory responses of macrophages. rDPP was localized adjacent to the cellular membrane rather than in the cytoplasm, and rDPP was able to bind to lipopolysaccharide. These results suggested that rDPP inhibited lipopolysaccharide-induced inflammatory responses by binding to lipopolysaccharide. Conclusions: In addition to the well-known functions of DPP for dentin mineralization that depend on the SDrr, we demonstrated that DPP possesses anti-inflammatory effects on lipopolysaccharide-stimulated macrophages that are independent of the SDrr.

DOI： 10.1016/j.archoralbio.2019.104634

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It is well known that dental pulp tissue can evoke some of the most severe acute inflammation observed in the human body. We found that dental pulp cells secrete a factor that induces tumor necrosis factor-α production from macrophages, and designated this factor, dental pulp cell-derived powerful inducer of TNF-α (DPIT). DPIT was induced in dental pulp cells and transported to recipient cells via microvesicles. Treatment of dental pulp cells with a PKR inhibitor markedly suppressed DPIT activity, and weak interferon signals were constitutively activated inside the cells. In recipient macrophages, stimulation with DPIT-containing supernatants from pulp cells resulted in activation of both nuclear factor-κB and MAP kinases like JNK and p38. Proteomics analyses revealed that many stress granule-related proteins were present in supernatants from dental pulp cells as well as microvesicle marker proteins like GAPDH, β-actin, HSPA8, HSPB1, HSPE1, and HSPD1. Furthermore, giant molecule AHNAK and PKR were detected in microvesicles derived from dental pulp cells, and gene silencing of AHNAK in dental pulp cells led to reduced DPIT activity. Thus, it appeared that the core protein of DPIT was PKR, and that PKR was maintained in an active state in stress granule aggregates with AHNAK and transported via microvesicles. The activity of DPIT for TNF-α induction was far superior to that of gram-negative bacterial endotoxin. Therefore, we, report for the first time, that active PKR is transported via microvesicles as stress granule aggregates and induces powerful inflammatory signals in macrophages.

DOI： 10.1038/s41598-019-40046-2

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© 2019 International Endodontic Journal. Published by John Wiley & Sons Ltd Aim: To investigate whether glycosaminoglycans (GAGs) binding to high-dose LL37 eliminates its cytotoxicity to dental pulp cells (hDPCs) whilst retaining undiminished antimicrobial and LPS-neutralizing abilities. Methodology: hDPCs were stimulated with varying concentrations of LL37, and their cell viability was analysed by MTT. Then, high-dose LL37 (10 μmol L−1) was bound to varying concentrations of three GAGs, heparin, chondroitin sulphate and hyaluronic acid, and their cytotoxic effects on hDPCs and antimicrobial effects were evaluated and compared. Furthermore, the LPS-neutralizing ability of heparin (5 μg mL−1)–LL37 (10 μmol L−1) complexes, which were found to be less cytotoxic for hDPCs with undiminished antimicrobial ability, was investigated. Statistical analysis was performed using one-way analysis of variance (anova), followed by Dunnett's test. P values below 0.05 were considered significant. Results: LL37 significantly reduced the cell viability of hDPCs in a dose-dependent manner (P < 0.01). LL37 (10 μmol L−1) binding to heparin within a limited concentration range (2~6 μg mL−1) eliminated the cytotoxicity for hDPCs (P < 0.01) whilst exerting potent antimicrobial effects against Streptococcus mutans, Streptococcus sobrinus, Streptococcus salivarius, Aggegatibacter actinomycetemcomitans and Escherichia coli. LL37 (10 μmol L−1) binding to chondroitin sulphate exhibited similar functions (P < 0.01); however, the effective chondroitin sulphate concentration was highly restricted (3 μg mL−1). LL37 (10 μmol L−1) binding to hyaluronic acid was unable to abrogate the cytotoxicity of LL37 even at higher concentrations (10 and 100 μg mL−1). Moreover, exogenous addition of LPS dose-dependently reduced the amount of LL37 precipitated with the heparin–LL37 agarose beads (P < 0.01), and the released LL37 simultaneously neutralized the pro-inflammatory ability of LPS in macrophages (P < 0.01). Conclusions: Heparin–LL37 complexes generated at suitable concentration ratios are easy to make, are less cytotoxic and are broad-range antimicrobial materials that can neutralize LPS by providing LL37 in accordance with the amount of free LPS. They may be a potential treatment to save dental pulp tissue from the acute inflammation exacerbated by invading bacteria and the LPS they release.

DOI： 10.1111/iej.13130

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In the oral mechanical environment, periodontal ligament cells (PDL cells) contribute to maintaining periodontal tissue homeostasis. Recent studies showed that exosomes, which are small vesicles secreted by various types of cells, play a pivotal role in cell-to-cell communication in biological processes. We examined the secretion of exosomes from PDL cells stimulated with cyclic stretch and their role in the inflammatory response of macrophages using the human macrophage cell line THP-1 and human primary monocytes/macrophages. We prepared supernatants from human PDL cells (PDL-sup) stimulated with cyclic stretch. The treatment of macrophages with PDL-sup, but not PDL-sup from unstimulated PDL cells, inhibited the production of IL-1β in LPS/nigericin-stimulated macrophages. The pretreatment of PDL cells with GW4869, an inhibitor of exosome secretion, or siRNA for Rab27B, which controls exosome secretion, abrogated the inhibitory effects of PDL-sup. A transmission electron microscopy analysis demonstrated the existence of exosomes with diameters ranging between 30 and 100 nm in PDL-sup, suggesting that exosomes in PDL-sup contribute to this inhibition. An immunofluorescence microscopy analysis revealed that exosomes labeled with PKH67, a fluorescent dye, were incorporated by macrophages as early as 2 h after the addition of exosomes. Purified exosomes inhibited IL-1β production in LPS/nigericin-stimulated macrophages and the nuclear translocation of NF-κB as well as NF-κB p65 DNA-binding activity in LPS-stimulated macrophages, suggesting that exosomes suppress IL-1β production by inhibiting the NF-κB signaling pathway. Our results indicate that PDL cells in mechanical environments contribute to the maintenance of periodontal immune/inflammatory homeostasis by releasing exosomes.

DOI： 10.3389/fimmu.2019.01310

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Authorship：Corresponding author   Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：(NPO)日本歯周病学会  

非翻訳長鎖RNA(IncRNA)はエピジェネティクスな遺伝子発現調節機構を担う主要な制御因子であると認識されてきている。炎症性疾患では特徴的なIncRNAが同定されており、歯周炎においてもいくつかの歯周炎関連遺伝子座を近傍または遠隔に制御するIncRNAの存在が推定される。IncRNAと歯周炎、歯周組織恒常性維持責任遺伝子座であるSIB-LINGs、unspliced DMP-1による近傍遺伝子発現制御について概説した。

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© 2017 Elsevier Inc. Chromatin-enriched noncoding RNAs (ncRNAs) have emerged as key molecules in epigenetic processes by interacting with chromatin-associated proteins. Recently, protein-coding mRNA genes have been reported to be chromatin-tethered, similar with ncRNA. However, very little is known about whether chromatin-enriched mRNA is involved in the chromatin modification process. Here, we comprehensively examined chromatin-enriched RNA in squamous cell carcinoma (SQCC) cells by RNA subcellular localization analysis, which was a combination of RNA fractionation and RNA-seq. We identified 11 mRNAs as highly chromatin-enriched RNAs. Among these, we focused on the dentin matrix protein-1 (DMP-1) gene because its expression in SQCC cells has not been reported. Furthermore, we clarified that DMP-1 mRNA was retained in chromatin in its unspliced form in SQCC in vitro and in vivo. As the inhibition of the unspliced DMP-1 mRNA (unspDMP-1) expression resulted in decreased cellular proliferation in SQCC cells, we performed ChIP-qPCR to identify cell cycle-related genes whose expression was epigenetically modified by unspDMP-1, and found that the CDKN1B promoter became active in SQCC cells by inhibiting unspDMP-1 expression. This result was further validated by the increased CDKN1B gene expression in the cells treated with siRNA for unspDMP-1 and by restoration of the decreased cellular proliferation rate by simultaneously inhibiting CDKN1B expression in SQCC cells. Further, to examine whether unspDMP-1 was able to associate with the CDKN1B promoter region, SQCC cells stably expressing PP7-mCherry fusion protein were transiently transfected with the unspDMP-1 fused to 24 repeats of the PP7 RNA stem loop (unspDMP-1-24xPP7) and we found that unspDMP-1-24xPP7 was efficiently precipitated with the antibody against mCherry and was significantly enriched in the CDKN1B promoter region. Thus, unspDMP-1 is a novel chromatin-enriched RNA that epigenetically regulates cellular proliferation of SQCC.

DOI： 10.1016/j.bbrc.2017.12.136

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCI LTD  

Background and aims: Epicatechin (EC) intake has been suggested to be beneficial for the prevention of cardiovascular disorders, and it is well known that adipose tissue inflammation is one of the major risk factors for coronary heart diseases. The purpose of the present study was to determine the in vitro and in vivo effects of EC on adipose tissue inflammation and obesity.
Methods and results: DNA microarray analysis was performed to evaluate the effects of EC on gene expression in adipocytes co-cultured with bacterial endotoxin-stimulated macrophages. To determine the in vivo effects of the catechin, C57BL/6 mice were fed either a high-fat diet (HFD) or HFD combined with EC, and metabolic changes were observed EC suppressed the expression of many inflammatory genes in the adipocytes co-cultured with endotoxinstimulated macrophages. Specifically, EC markedly suppressed chemokine (C-C motif) ligand 19 (CCL19) expression. The target cell of EC appeared to macrophages. The in vivo study indicated that mice fed the EC-supplemented HFD were protected from diet-induced obesity and insulin resistance. Accordingly, the expression levels of genes associated with inflammation in adipose tissue and in the liver were downregulated in this group of mice.
Conclusions: EC exerts beneficial effects for the prevention of adipose tissue inflammation and insulin resistance. Since we previously reported that mice deficient in the CCL19 receptor were protected from diet-induced obesity and insulin resistance, it can be concluded that the beneficial effects of EC could be mediated, at least in part, by marked suppression of CCL19 expression. (C) 2016 The Italian Society of Diabetology, the Italian Society for the Study of Atherosclerosis, the Italian Society of Human Nutrition, and the Department of Clinical Medicine and Surgery, Federico II University. Published by Elsevier B.V. All rights reserved.

DOI： 10.1016/j.numecd.2016.11.008

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Authorship：Lead author,　Corresponding author   Language：English   Publisher：Japanese Association for Oral Biology  

Background Dentin sialophosphoprotein (DSPP) belongs to the family of small integrin-binding ligand N-linked glycoproteins (SIBLINGs), which share common biochemical features such as an arginine-glycine-aspartic acid (RGD) integrin-binding site. However, amino acid sequence analyses suggest that DSPP has lost some common features, but acquired other unique features, such as repeat sequences of serine-serine-aspartic acid (SDrr) that are not observed in other SIBLINGs proteins. Highlight We review the biochemical features of DSPP using genetically modified mice and proteomic analyses. DSPP of some species lack the RGD sites unlike other SIBLING proteins such as dentin matrix protein-1 (DMP-1) and bone sialoprotein (BSP). We previously identified that mouse and human RGD domains in DSPP required the cleavage of an Ala-Ser peptide bond, next to the RGD domains, to become active. Other species such as bovine, sheep, and bears, possess a Thr-Ser bond next to the RGD domain, which is intrinsically unable to sequester the ability of the RGD domain. To predict the functional importance of certain proteins/domains based on evolutionary conservation rates, the RGD domain of DSPP did not appear to have pivotal roles compared to other SIBLINGs. However, upon investigating the peptide bond next to the RGD domains of DSPP in 37 species, we found most catarrhini, in which humans are classified, possess the Ala-Ser bond. Conclusion The functions of DSPP for integrin-mediated signaling possibly arize from the proteolytic cleavage of the peptide bonds close to the RGD domain and induce reactionary dentinogenesis in vivo.

DOI： 10.1016/j.job.2016.08.002

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

DOI： 10.1016/j.bbrep.2016.04.004

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Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

Objective: Phosphophoryn (PP) is generated from the proteolytic cleavage of dentin sialophosphoprotein (DSPP). PP which contains tandem serine/asparatic acid rich repeats (SDrr) is known to enhance dentin mineralization. The nucleotide sequences coding SDrr are identified in the DSPP genes of toothed animals and the length variations of SDrr between intra- and inter-species have been reported. However, it remains unknown about the relationship between the length variations in SDrr and the functions of PP in matrix mineralization.
Design: By utilizing a mammalian expression system, we generated several recombinant PP proteins (rPP) containing SDrr of different lengths and analyzed their effects on the precipitation of calcium phosphate with an in vitro gel diffusion system.
Results: rPP-Delta 37.6 SDrr and rPP-Delta 63.5 SDrr, which possessed shortened SDrr that accounted for 62.4 and 36.5% the length of SDrr in full-length rPP (rPP-full), respectively, induced the precipitation of calcium phosphate similar to that of rPP-full at the same molar concentration, whereas rPP-Delta SDrr, in which SDrr were flipped, did not. Furthermore, rPP-Delta 63.5 SDrr significantly increased the accumulation of calcium compared with rPP-full at adjusted concentrations so that the same amounts of SDrr were embedded. The results of an ELISA analysis indicated that the amounts of rPP-Delta 37.6 SDrr and rPP-Delta 63.5 SDrr secreted from transfected cells were 5.2- and 7.1-fold greater than that of rPP-full, respectively.
Conclusions: The generated rPP-Delta 63.5 SDrr which can be substituted for rPP-full may be a candidate for a therapeutic molecule to facilitate hard tissue generation such as reparative dentin formation. (C) 2015 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.archoralbio.2015.05.013

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-BLACKWELL  

Wnt proteins are lipid-modified, short-range signals that control stem cell self-renewal and tissue regeneration. We identified a population of Wnt responsive cells in the pulp cavity, characterized their function, and then created a pulp injury. The repair response was evaluated over time using molecular, cellular, and quantitative assays. We tested how healing was impacted by wound environments in which Wnt signaling was amplified. We found that a Wnt-amplified environment was associated with superior pulp healing. Although cell death was still rampant, the number of cells undergoing apoptosis was significantly reduced. This resulted in significantly better survival of injured pulp cells, and resulted in the formation of more tertiary dentin. We engineered a liposome-reconstituted form of WNT3A then tested whether this biomimetic compound could activate cells in the injured tooth pulp and stimulate dentin regeneration. Pulp cells responded to the elevated Wnt stimulus by differentiating into secretory odontoblasts. Thus, transiently amplifying the body's natural Wnt response resulted in improved pulp vitality. These data have direct clinical implications for treating dental caries, the most prevalent disease affecting mankind. (c) 2015 American Society for Bone and Mineral Research.

DOI： 10.1002/jbmr.2444

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Authorship：Lead author,　Corresponding author   Publishing type：Research paper (scientific journal)   Publisher：Public Library of Science (PLoS)  

Phosphophoryn (PP) is generated from the proteolytic cleavage of dentin sialophosphoprotein (DSPP). Gene duplications in the ancestor dentin matrix protein-1 (DMP-1) genomic sequence created the DSPP gene in toothed animals. PP and DMP-1 are phosphorylated extracellular matrix proteins that belong to the family of small integrin-binding ligand N-linked glycoproteins (SIBLINGs). Many SIBLING members have been shown to evoke various cell responses through the integrinbinding Arg-Gly-Asp (RGD) domain; however, the RGD-dependent function of PP is not yet fully understood. We demonstrated that recombinant PP did not exhibit any obvious cell adhesion ability, whereas the simultaneously purified recombinant DMP-1 did. A cell adhesion inhibitory analysis was performed by pre-incubating human osteosarcoma MG63 cells with various PP peptides before seeding onto vitronectin. The results obtained revealed that the incorporation of more than one amino acid on both sides of the PP-RGD domain was unable to inhibit the adhesion of MG63 cells onto vitronectin. Furthermore, the inhibitory activity of a peptide containing the PP-RGD domain with an open carboxyl-terminal side (H-463SDESDTNSESANESGSRGDA482-OH) was more potent than that of a peptide containing the RGD domain with an open amino-terminal side (H-478SRGDASYTSDESSDDDNDSDSH499-OH). This phenomenon was supported by the potent cell adhesion and migration abilities of the recombinant truncated PP, which terminated with Ala482. Furthermore, various point mutations in Ala482 and/or Ser483 converted recombinant PP into cell-adhesive proteins. Therefore, we concluded that the Ala482-Ser483 flanking sequence, which was detected in primates and mice, was the key peptide bond that allowed the PPRGD domain to be sequestered. The differential abilities of PP and DMP-1 to act on integrin imply that DSPP was duplicated from DMP-1 to serve as a crucial extracellular protein for tooth development rather than as an integrin-mediated signaling molecule.

DOI： 10.1371/journal.pone.0112490

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BackgroundChronic kidney disease (CKD) is an important risk factor for coronary heart disease, and previous studies indicated the involvement of low-grade inflammation in the pathogenesis of CKD.MethodsThe study was designed to (i) identify and confirm genes and their products upregulated in mesangial cells cocultured with endotoxin-stimulated macrophages and (ii) determine the clinical relevance of genes and proteins upregulated in mesangial cells under inflammatory conditions by an epidemiological approach.ResultsDNA microarray analysis revealed upregulated expression of many genes and their products including several cytokines and chemokines, as well as the inflammatory marker, lipocalin 2 gene. The gene expression and protein upregulation of lipocalin 2 were synergistically affected by endotoxin and tumor necrosis factor (TNF)-α stimulation. In human studies, lipocalin 2 level was significantly associated with creatinine (r = 0.419, P < 0.001) and negatively associated with eGFR (r = -0.365, P < 0.001). Multiple logistic regression analysis revealed a significant association between lipocalin 2 and soluble tumor necrosis factor receptor 2 (sTNF-R2), eGFR and uric acid in general subjects attending regular annual medical check-up (n = 420). When subjects with diabetes were excluded from the analysis, lipocalin 2 remained associated with sTNF-R2, eGFR and uric acid.ConclusionsSince an activated TNF system, as demonstrated by elevated sTNF-R2, and elevated uric acid were recently implicated in an elevated CKD risk, we conclude that inflammation could play an important role in the pathogenesis of CKD, and that lipocalin 2 is a potential universal marker for impaired kidney function. Furthermore, the results obtained by the current microarray analysis could improve the understanding of gene profiles associated with the pathophysiology of CKD under inflammatory conditions. © 2013 © The Author 2013. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved.

DOI： 10.1093/ndt/gft449

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Authorship：Lead author,　Corresponding author   Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japanese Society of Conservative Dentistry  

Purpose: Matrix trioxide aggregate (MTA) has been used for direct pulp-capping as well as perforation repair due to its potent ability to induce hard tissue regeneration. Pulp exposure, usually caused by tooth fracture and carious tooth treatment, involves the physical damage of pulp extracellular matrix. Therefore, when cells invade the damaged space from surrounding tissue, the existence of an adhesive substrate to aid cell proliferation and differentiation of invading cells is the key factor influencing the prognosis of pulp-capping treatment. In this study, we examined the effects of MTA on the adhesion, proliferation and apoptosis of human dental pulp cells (hDPCs) by comparison with composite resin (CR) and glass ionomer cement (GIC).<br> Materials and methods: Ninety-six-well plates were coated with MTA, CR, GIC and fibronectin. Cells were suspended in serum-free medium and then seeded onto coated wells. After 1.5-hr incubation at 37°C, the wells were rinsed to remove non-adherent cells. The number of adherent cells was quantified using the Cell Titer Glo Luminescent Cell Viability Assay Kit. For proliferation assay, these cells were seeded onto MTA, CR and GIC and attached cells were quantified. After 1.5-hr incubation, serum-free medium was replaced with 10% serum medium and cells were cultured onto these substrates for 72 hrs. The ability to induce apoptosis was evaluated by caspase 3/7 activity.<br> Result: MTA facilitated the adhesion of hDPCs, while CR and GIC did not. However, the adhesive effect of MTA was much weaker than that of fibronectin. hDPCs could attach onto MTA but not CR or GIC, even 72 hrs after seeding, although the number of attached cells gradually decreased during the culture period. These observations suggest that MTA could be used as a substrate for the adhesion, but not a scaffold for the proliferation, of hDPCs. A drastic increase of caspase 3/7 activity was observed when hDPCs were cultured onto CR and GIC. In contrast, MTA did not induce it.<br> Conclusions: Compared with CR and GIC, MTA is a good substrate for hDPC adhesion. These differential adhesive effects may be explained by the differential abilities for inducing pro-apoptotic signals in hDPCs. However, the effect of MTA as a cell adhesion substrate was much weaker than that of fibronectin. More importantly, MTA was unable to induce the proliferation of hDPCs on it. Thus, the co-addition of MTA with other adhesive and migratory proteins such as fibronectin may induce better wound healing and pulp tissue regeneration in vivo.

DOI： 10.11471/shikahozon.57.547

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Other Link： http://search.jamas.or.jp/link/ui/2015182150

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.2174/978160805465711202010221

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

Dentin sialophosphoprotein (DSPP) and dentin matrix protein-1 (DMP-1) are highly phosphorylated proteins that belong to the family of small integrin-binding ligand N-linked glycoproteins (SIBLINGs), and are essential for proper development of hard tissues such as teeth and bones. In order to understand how they contribute to tissue organization, DSPP and DMP-1 have been analyzed for over a decade using both in vivo and in vitro techniques. Among the five SIBLINGs, the DSPP and DMP-1 genes are located next to each other and their gene and protein structures are most similar. In this review we examine the phenotypes of the genetically engineered mouse models of DSPP and DMP-1 and also introduce complementary in vitro studies into the molecular mechanisms underlying these phenotypes. DSPP affects the mineralization of dentin more profoundly than DMP-1. In contrast, DMP-1 significantly affects bone mineralization and importantly controls serum phosphate levels by regulating serum FGF-23 levels, whereas DSPP does not show any systemic effects. DMP-1 activates integrin signalling and is endocytosed into the cytoplasm whereupon it is translocated to the nucleus. In contrast, DSPP only activates integrin-dependent signalling. Thus it is now clear that both DSPP and DMP-1 contribute to hard tissue mineralization and the tissues affected by each are different presumably as a result of their different expression levels. In fact, in comparison with DMP-1, the functional analysis of cell signalling by DSPP remains relatively unexplored. (C) 2012 Elsevier LtdElsevier Ltd. All rights reserved.

DOI： 10.1016/j.archoralbio.2012.03.005

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：BIOMED CENTRAL LTD  

Background: The effect of smoking on leptin regulation is controversial. Smoking may induce low-grade inflammation. Recent series of studies indicated the critical role of macrophage migration in the establishment of adipose tissue inflammation. In this study, we aimed to see the effects of smoking and inflammation on leptin regulation both at cellular and epidemiological levels.
Methods: We compared the concentration of inflammatory markers and serum leptin levels among Japanese male subjects. Additionally, leptin and intercellular adhesion molecule (ICAM) -1 gene expression was assessed in adipocytes co-cultured with or without macrophages in the presence or absence of nicotine and/or lipopolysaccharide (LPS).
Results: In subjects with BMI below 25 kg/m(2), both WBC counts and soluble-ICAM-1 levels are significantly higher in smokers than in non-smokers. However, leptin concentration did not differ according to smoking status. However, in subjects with BMI over 25 kg/m(2), smokers exhibited significantly lower serum leptin level as well as higher WBC counts and s-ICAM-1 concentration as compared with non-smokers. Leptin gene expression was markedly suppressed in adipocytes co-cultured with macrophages than in adipocyte culture alone. Furthermore, nicotine further suppressed leptin gene expression. ICAM-1 gene expression was markedly up-regulated in adipocytes co-cultured with macrophages when stimulated with LPS.
Conclusions: Adipose tissue inflammation appears to down-regulate leptin expression in adipose tissues. Nicotine further suppresses leptin expression. Thus, both smoking and inflammation may diminish leptin effect in obese subjects. Therefore, obese, but not normal weight, smokers might be more resistant to weight loss than nonsmokers.

DOI： 10.1186/1617-9625-10-3

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<jats:p>Tooth and bone specimen require extensive demineralization for careful analysis of cell morphology, as well as gene and protein expression levels. The LacZ gene, which encodes the ß-galactosidase enzyme, is often used as a reporter gene to study gene-structure function, tissue-specific expression by a promoter, cell lineage and fate. This reporter gene is particularly useful for analyzing the spatial and temporal gene expression pattern, by expressing the LacZ gene under the control of a promoter of interest. To analyze LacZ activity, and the expression of other genes and their protein products in teeth and bones, it is necessary to carry out a complete demineralization of the specimen before cutting sections. However, strong acids, such as formic acid used for tooth demineralization, destroy the activities of enzymes including those of ß-galactosidase. Therefore, most protocols currently use mild acids such as 0.1 M ethylene diamine tetra-acetic acid (EDTA) for demineralization of tooth and bone specimen, which require a longer period of treatment for complete demineralization. A method by which hard tissue specimens such as teeth and bones can be rapidly, but gently, decalcified is necessary to save time and effort. Here, we report a suitable method for rapid demineralization of mouse teeth in 0.1M EDTA at 42˚C without any loss of ß-galactosidase activity.</jats:p>

DOI： 10.2174/1874210601004010223

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Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：ACADEMIC PRESS INC ELSEVIER SCIENCE  

Transforming growth factor-beta 1 (TGF-beta 1) is secreted as a latent complex, which consists of latency-associated peptide (LAP) and the mature ligand. The release of the mature ligand from LAP usually occurs through conformational change of the latent complex and is therefore considered to be the first step in the activation of the TGF-beta signaling pathway. So far, factors such as heat, pH changes, and proteolytic cleavage are reportedly involved in this activation process, but the precise molecular mechanism is still far from clear. Identification and characterization of the cell surface proteins that bind to LAP are important to our understanding of the latent TGF-beta activation process. In this study, we have identified heat shock protein 90 beta (HSP90 beta) from the cell surface of the MG63 osteosarcoma cell line as a LAP binding protein. We have also found that MG63 cells secrete HSP90 beta into extracellular space which inhibits the activation of latent TGF-beta 1, and that there is a subsequent decrease in cell proliferation. TGF-beta 1 -mediated stimulation of MG63 cells resulted in the increased cell surface expression of HSP90 beta. Thus, extracellular HSP90 beta is a negative regulator for the activation of latent TGF-beta 1 modulating TGF-beta signaling in the extracellular domain. Published by Elsevier Inc.

DOI： 10.1016/j.bbrc.2010.06.112

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DOI： 10.11471/shikahozon.53.73

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Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

Dentin sialophosphoprotein (DSPP), a major non-collagenous matrix protein of odontoblasts, is proteolytically cleaved into dentin sialoprotein (DSP) and dentin phosphoprotein (DPP). Our previous studies revealed that DSPP null mice display a phenotype similar to human autosomal dominant dentinogenesis imperfecta. in which teeth have widened predentin and irregular dentin mineralization resulting in sporadic unmineralized areas in dentin and frequent pulp exposure. Earlier in vitro studies suggested that DPP, but not DSP, plays a significant role in initiation and maturation of dentin mineralization. However, the precise in vivo roles of DSP and DPP are far from clear. Here we report the generation of DPPcKO mice, in which only DSP is expressed in a DSPP null background, resulting in a conditional DPP knockout. DPPcKO teeth show a partial rescue of the DSPP null phenotype with the restored predentin width, an absence of irregular unmineralized areas in dentin, and less frequent pulp exposure. Micro-computed tomography (micro-CT) analysis of DPPcKO molars further confirmed this partial rescue with a significant recovery in the dentin volume, but not in the dentin mineral density. These results indicate distinct roles of DSP and DPP in dentin mineralization, with DSP regulating initiation of dentin mineralization, and DPP being involved in the maturation of mineralized dentin. Published by Elsevier B.V.

DOI： 10.1016/j.matbio.2009.03.006

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Targeted disruption of the dentin sialophosphoprotein (DSPP) gene in the mice (Dspp(-/-)) results in dentin mineralization defects with enlarged predentin phenotype similar to human dentinogenesis imperfecta type Ill. Using DSPP/biglycan (Dspp(-/-)Bgn(-/0)) and DSPP/decorin (Dspp(-/-)Dcn(-/-)) double knockout mice, here we determined that the enlarged predentin layer in Dspp(-/-) teeth is rescued in the absence of decorin, but not in the absence of biglycan. However, Fourier transform infrared (FTIR) spectroscopy analysis reveals similar hypomineralization of dentin in both Dspp(-/-)Bgn(-/0) and Dspp(-/-)Dcn(-/-) teeth. Atomic force microscopy (AFM) analysis of collagen fibrils in dentin shows subtle differences in the collagen fibril morphology in these genotypes. The reduction of enlarged predentin in Dspp(-/-)Dcn(-/-) mice suggests that the elevated level of decorin in Dspp(-/-) predentin interferes with the mineralization process at the dentin mineralization front. On the other hand, the lack of DSPP and biglycan leads to the increased number of calcospherites in Dspp(-/-)Bgn(-/0) predentin, suggesting that a failure in coalescence of calcospherites was augmented in Dspp(-/-)Bgn(-/0) teeth as compared to Dspp(-/-) teeth. These findings indicate that normal expression of small leucine rich proteoglycans, such as biglycan and decorin, plays an important role in the highly orchestrated process of dentin mineralization. Published by Elsevier B.V.

DOI： 10.1016/j.matbio.2009.01.005

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SAGE PUBLICATIONS INC  

Amelogenin and ameloblastin, the major enamel matrix proteins, are important for enamel mineralization. To identify their synergistic roles in enamel development, we generated Amel X(-/-)/Ambn(-/-) mice. These mice showed additional enamel defects in comparison with Amel X(-/-) or Ambn(-/-) mice. In 7-day-old Amel X(-/-)/Ambn(-/-) mice, not only was the ameloblast layer irregular and detached from the enamel surface, as in Ambn(-/-), but also, the enamel width was significantly reduced in the double-null mice as compared with Amel X(-/-) or Ambn(-/-) mice. Proteomic analysis of the double-null teeth revealed increased levels of RhoGDI (Arhgdia), a Rho-family-specific guanine nucleotide dissociation inhibitor, which is involved in important cellular processes, such as cell attachment. Both Amel X(-/-)/Ambn(-/-) mice and Ambn(-/-) mice displayed positive staining with RhoGDI antibody in the irregularly shaped ameloblasts detached from the matrix. Ameloblastin-regulated expression of RhoGDI suggests that Rho-mediated signaling pathway might play a role in enamel formation.

DOI： 10.1177/0022034509334749

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Language：Japanese   Publishing type：Research paper, summary (national, other academic conference)   Publisher：The Japanese Society of Conservative Dentistry  

Purpose: Matrix trioxide aggregate (MTA) has been used for direct pulp-capping as well as perforation repair due to its potent ability to induce hard tissue regeneration. Pulp exposure, usually caused by tooth fracture and carious tooth treatment, involves the physical damage of pulp extracellular matrix. Therefore, when cells invade the damaged space from surrounding tissue, the existence of an adhesive substrate to aid cell proliferation and differentiation of invading cells is the key factor influencing the prognosis of pulp-capping treatment. In this study, we examined the effects of MTA on the adhesion, proliferation and apoptosis of human dental pulp cells (hDPCs) by comparison with composite resin (CR) and glass ionomer cement (GIC).<br> Materials and methods: Ninety-six-well plates were coated with MTA, CR, GIC and fibronectin. Cells were suspended in serum-free medium and then seeded onto coated wells. After 1.5-hr incubation at 37°C, the wells were rinsed to remove non-adherent cells. The number of adherent cells was quantified using the Cell Titer Glo Luminescent Cell Viability Assay Kit. For proliferation assay, these cells were seeded onto MTA, CR and GIC and attached cells were quantified. After 1.5-hr incubation, serum-free medium was replaced with 10% serum medium and cells were cultured onto these substrates for 72 hrs. The ability to induce apoptosis was evaluated by caspase 3/7 activity.<br> Result: MTA facilitated the adhesion of hDPCs, while CR and GIC did not. However, the adhesive effect of MTA was much weaker than that of fibronectin. hDPCs could attach onto MTA but not CR or GIC, even 72 hrs after seeding, although the number of attached cells gradually decreased during the culture period. These observations suggest that MTA could be used as a substrate for the adhesion, but not a scaffold for the proliferation, of hDPCs. A drastic increase of caspase 3/7 activity was observed when hDPCs were cultured onto CR and GIC. In contrast, MTA did not induce it.<br> Conclusions: Compared with CR and GIC, MTA is a good substrate for hDPC adhesion. These differential adhesive effects may be explained by the differential abilities for inducing pro-apoptotic signals in hDPCs. However, the effect of MTA as a cell adhesion substrate was much weaker than that of fibronectin. More importantly, MTA was unable to induce the proliferation of hDPCs on it. Thus, the co-addition of MTA with other adhesive and migratory proteins such as fibronectin may induce better wound healing and pulp tissue regeneration in vivo.

DOI： 10.11471/shikahozon.57.547

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Publishing type：Research paper, summary (national, other academic conference)  

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Language：Japanese   Publishing type：Research paper, summary (national, other academic conference)   Publisher：(NPO)日本歯周病学会  

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Publishing type：Research paper, summary (national, other academic conference)  

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Publishing type：Research paper, summary (national, other academic conference)  

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Language：Japanese   Publisher：(NPO)日本歯周病学会  

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Publishing type：Research paper, summary (national, other academic conference)  

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Language：Japanese   Publishing type：Research paper, summary (international conference)   Publisher：JAPANESE SOCIETY OF PERIODONTOLOGY  

DOI： 10.14833/amjsp.2011s.0.23.0

CiNii Article

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Publishing type：Research paper, summary (international conference)  

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Publishing type：Research paper, summary (national, other academic conference)  

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Publishing type：Research paper, summary (national, other academic conference)  

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Publishing type：Research paper, summary (national, other academic conference)  

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Publishing type：Research paper, summary (national, other academic conference)  

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Publishing type：Research paper, summary (national, other academic conference)  

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Publishing type：Research paper, summary (international conference)  

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Publishing type：Research paper, summary (national, other academic conference)  

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Publishing type：Research paper, summary (international conference)  

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Language：Japanese  

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Publishing type：Research paper, summary (international conference)  

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Language：Japanese   Publisher：日本炎症・再生医学会  

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Language：Japanese  

DOI： 10.14833/amjsp.2006s.0.71.0

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Language：Japanese   Publisher：(NPO)日本歯周病学会  

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Language：Japanese   Publisher：日本炎症・再生医学会  

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Language：Japanese   Publisher：(NPO)日本歯周病学会  

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Publishing type：Research paper, summary (international conference)  

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Publishing type：Research paper, summary (international conference)  

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Language：Japanese   Publisher：(NPO)日本歯周病学会  

CiNii Article

CiNii Books

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Language：Japanese   Publisher：(NPO)日本歯周病学会  

CiNii Article

CiNii Books

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Language：Japanese   Publisher：(NPO)日本歯周病学会  

CiNii Article

CiNii Books

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Language：Japanese   Publisher：(NPO)日本歯周病学会  

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Language：Japanese   Publisher：(NPO)日本歯周病学会  

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Language：Japanese   Publisher：大阪大学歯学会  

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Language：English   Presentation type：Oral presentation (invited, special)  

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Language：English   Presentation type：Oral presentation (invited, special)  

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Language：Japanese   Presentation type：Oral presentation (invited, special)  

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Language：Japanese   Presentation type：Oral presentation (invited, special)  

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Language：English   Presentation type：Oral presentation (invited, special)  

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