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Abstract
Dental pulp stem cells (DPSCs) are a unique precursor population isolated from postnatal human dental pulp and have the ability to regenerate a reparative dentin-like complex. Canonical Wnt signaling plays a critical role in tooth development and stem cell self-renewal through beta-catenin. In this study, the regulation of odontoblast-like differentiation of DPSCs by canonical Wnt signaling was examined. DPSCs were stably transduced with canonical Wnt-1 or the active form of beta-catenin, with retrovirus-mediated infection. Northern blot analysis found that Wnt-1 strongly induced the expression of matricellular protein osteopontin, and modestly enhanced the expression of type I collagen in DPSCs. Unexpectedly, Wnt-1 inhibited alkaline phosphatase (ALP) activity and the formation of mineralized nodules in DPSCs. Moreover, over-expression of beta-catenin was also sufficient to suppress the differentiation and mineralization of DPSCs. In conclusion, our results suggest that canonical Wnt signaling negatively regulates the odontoblast-like differentiation of DPSCs.
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Jing W, Wu L, Lin Y, Liu L, Tang W, Tian W. Odontogenic differentiation of adipose-derived stem cells for tooth regeneration: necessity, possibility, and strategy. Med Hypotheses 2008; 70:540-2. [PMID: 17703893 DOI: 10.1016/j.mehy.2007.07.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2007] [Accepted: 07/11/2007] [Indexed: 01/03/2023]
Abstract
Tooth regeneration using tissue engineering concepts is a promising biological approach to solving problems of tooth loss in elderly patients. The seeding cells, however, for tooth regeneration such as odontoblasts from dental germ, stem cells from dental pulp and deciduous teeth, and ectomesenchymal cells from the first branchial arch are difficult, even impossible to harvest in clinic. Bone marrow mesenchymal stem cells have odontogenic capacity, but their differentiation abilities significantly decrease with the increasing age of the donors. Therefore, the cells mentioned above are not practical in the clinical application of tooth regeneration in the old. Adipose derived stem cells have many clinical advantages over bone marrow mesenchymal stem cells, and their differentiation potential can be maintained with aging. Here we propose the hypothesis that adipose derived stem cells could be induced into odontogenic lineage and might be used as suitable seeding cells for tooth regeneration to replace the lost tooth of elderly patients.
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Téclès O, Laurent P, Aubut V, About I. Human tooth culture: A study model for reparative dentinogenesis and direct pulp capping materials biocompatibility. J Biomed Mater Res B Appl Biomater 2008; 85:180-7. [PMID: 17853422 DOI: 10.1002/jbm.b.30933] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In a previous work, based on an in vitro entire tooth culture model of human immature third molars, we demonstrated that perivascular progenitor cells can proliferate and migrate to the injury site after pulp exposure. In this work, we investigated the differentiation of cells after direct capping with biomaterials classically used in restorative dentistry. Histological staining after direct pulp capping with Calcium Hydroxide XR(R) or MTA revealed early and progressive mineralized foci formation containing BrdU-labeled sequestered cells. The molecular characterization of the matrix and the sequestered cells by immunohistochemistry (Collagene type I, Dentin sialoprotein, and Nestin) clearly demonstrates that these areas share common characteristics of the mineralized matrix of reparative dentin formed by odontoblast-like cells. This reproduces some features of the pulp responses after applying these materials in vivo and demonstrates that the entire tooth culture model reproduces a part of the early steps of dentin regeneration in vivo. Its future development may be useful in studying the effects of biomaterials on this process.
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Abstract
Pain serves as a warning of impending injury, triggering appropriate protective responses. Emotional and cognitive processing in the brain is involved in the sensation of pain. As Ca(2+) waves in keratinocytes are mediated by the release of extracellular molecules such as signaling molecules, this may also affect the activity of surrounding cells such as sensory neurons. Although no junctions have been found between keratinocytes and sensory termini, ultrastructural studies have shown that keratinocytes come into contact with dorsal root ganglion neurons through membrane-membrane apposition. There is also indirect evidence that keratinocytes communicate with sensory neurons via extracellular molecules. Sensory neurons themselves sense various external stimuli, but there may also be skin-derived regulatory mechanisms by which sensory signaling is modulated.First, we will give a general outline of the subject: 1) Progress in identifying cortical loci that process pain messages is needed. 2) Far greater advances have been made in understanding the molecular mechanisms whereby primary sensory neurons detect pain-producing stimuli. 3) Genetic studies have facilitated the identification and functional characterization of molecules. 4) Now, the relationship between sensory and ion channels has become clear.
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Scheven BA, Millard JL, Cooper PR, Lea SC, Walmsley AD, Smith AJ. Short-term in vitro effects of low frequency ultrasound on odontoblast-like cells. ULTRASOUND IN MEDICINE & BIOLOGY 2007; 33:1475-82. [PMID: 17531373 DOI: 10.1016/j.ultrasmedbio.2007.03.010] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2006] [Revised: 03/13/2007] [Accepted: 03/21/2007] [Indexed: 05/15/2023]
Abstract
In this study, the effects of low frequency ultrasound (US) were examined on odontoblasts, the primary cell responsible for dentinogenesis and dentine repair. An established odontoblast-like cell line, MDPC-23, was subjected to 30 kHz ultrasound at three different power settings. US induced a marginal level of cell death (3% to 4%) at lower amplitudes rising to 25% cell death at the highest power tested. The latter was reflected in a 30% decrease in cell attachment after 4 to 24 h of culture, while the number of adherent cells was reduced by approximately 10% to 15% in the lower power groups. Cell replication after 24 h, as measured by BrdU incorporation, showed no significant changes in the US-treated groups. Gene expression analyses demonstrated a moderate dose-dependent increase in the expression of GAPDH (glyseraldehyde-3-phosphate dehydrogenase)-normalised collagen type I, osteopontin (OPN), transforming growth factor-beta1 (TGFbeta1) and the heat shock protein (hsp) 70. The greatest change was found in the expression of the small hsp 25/27, which showed a two- to six-fold increase following US treatment. No significant effects were observed for alkaline phosphatase (ALP) and core-binding factor A1 (CBFA1/Runx2) expression levels. This is the first report describing US effects on odontoblasts. Further studies are warranted to elucidate US effects on odontoblast function and to evaluate US as a therapeutic application in dentine repair.
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Iejima D, Sumita Y, Kagami H, Ando Y, Ueda M. Odontoblast marker gene expression is enhanced by a CC-chemokine family protein MIP-3alpha in human mesenchymal stem cells. Arch Oral Biol 2007; 52:924-31. [PMID: 17532291 DOI: 10.1016/j.archoralbio.2007.04.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2006] [Revised: 04/05/2007] [Accepted: 04/06/2007] [Indexed: 01/09/2023]
Abstract
OBJECTIVE Macrophage inflammatory protein-3 alpha (MIP-3alpha) is a major CC-chemokine family protein, which serves as a differentiation factor for mesenchymal cells, including osteoblasts and dental pulp cells. The purpose of this study was to investigate the influence of MIP-3alpha on human mesenchymal stem cell differentiation in vitro. DESIGN Human mesenchymal stem cells were maintained in Dulbecco's modified Eagle's medium in the presence or absence of MIP-3alpha and the presence or absence of osteogenic factors (dexamethasone, beta-glycerophoshate and ascorbic acid). Alkaline phosphatase (ALP) activity was measured, and expression of odontoblast and osteoblast markers were examined by RT-PCR and Western blotting. RESULTS MIP-3alpha alone did not increase ALP activity, as compared to controls. The combination of MIP-3alpha and osteogenic factors increased ALP activity beyond increases observed with osteogenic factors alone. mRNA expression of the odontoblast marker dspp was only detectable when MIP-3alpha was added together with osteogenic factors at day 7 in three out of four samples. DSP protein level was increased only in the samples treated with both MIP-3alpha and osteogenic factors until day 5. In contrast, MIP-3alpha did not influence levels of the osteoblast markers CBFA1 or BSP. CONCLUSIONS The present study demonstrated that MIP-3alpha enhanced gene expression and protein levels of odontoblast-related genes, without affecting levels of the osteogenic proteins CBFA1 or BSP.
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Liu J, Jin T, Chang S, Ritchie HH, Smith AJ, Clarkson BH. Matrix and TGF-β-related gene expression during human dental pulp stem cell (DPSC) mineralization. In Vitro Cell Dev Biol Anim 2007; 43:120-8. [PMID: 17516126 DOI: 10.1007/s11626-007-9022-8] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2007] [Accepted: 04/02/2007] [Indexed: 10/23/2022]
Abstract
We have recently reported the induction of dental pulp stem cells (DPSCs) into dentin-secreting odontoblast-like cells after stimulation by isolated dentin matrix components, thus mimicking the nature of tissue regeneration seen after tooth disease and injury. After confluency, the cells were further cultured for 21 d in the 10% fetal bovine serum (FBS) Dulbecco's modified Eagle's medium (DMEM) (control), and in this medium, with the addition of dentin extract (DE) and the mineralization supplement (MS) of ascorbic acid and beta-glycerophosphate (treatment). To identify genes associated with this process, specimens were analyzed with a HG-U133A human gene chip and Arrayassist software. A total of 425 genes, among them 21 matrix and eight TGF-beta-related genes, were either up- or downregulated in the experimental group in which the cells showed odontoblast-like differentiation and mineralization. Expression of selected genes was further confirmed by real-time polymerase chain reaction (PCR) analysis. Of the extracellular matrix (ECM)-related genes, two types of collagen genes were upregulated and seven others downregulated. Other ECM-related genes, for example fibulin-1, tenascin C, and particularly thrombospondin 1, were upregulated, and fibulin-2 was downregulated. Most noticeably, the matrix metalloproteinase 1 was induced by the treatment. In the TGF-beta superfamily, upregulation of the type II receptor, endoglin, and growth/differentiation factor 5 was coordinated with the downregulation of activin A, TGF-beta2, and TGF-beta1 itself. This study identifies the matrix and TGF-beta-related gene profiles during the DPSC cell mineralization in which several genes are reported for the first time to be associated with this process, thus greatly expanding our molecular knowledge of the induced disease repair process.
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Li ZY, Chen L, Liu L, Lin YF, Li SW, Tian WD. Odontogenic potential of bone marrow mesenchymal stem cells. J Oral Maxillofac Surg 2007; 65:494-500. [PMID: 17307598 DOI: 10.1016/j.joms.2006.09.018] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2005] [Revised: 07/22/2006] [Accepted: 09/28/2006] [Indexed: 12/30/2022]
Abstract
PURPOSE This study aimed to investigate the odontogenic potential of bone marrow mesenchymal stem cells (BM-MSCs) for seeding in tooth regeneration. MATERIALS AND METHODS In this study, BM-MSCs were co-cultured with oral epithelial cells derived from rat embryos. Expression of the odontogenic genes Pax9, DMP1, and DSPP was detected by the reverse-transcription polymerase chain reaction (RT-PCR) technique. To further characterize the odontogenic potential of BM-MSCs, the gold standard in vivo transplantation system was used. RESULTS The results revealed that Pax9, DMP1, and DSPP expression was detected by RT-PCR only after co-culture of BM-MSCs and oral epithelial cells derived from embryos age E11.5. Histological analyses of the BM-MSCs/epithelial cell mass demonstrated the presence of tooth-like structures. CONCLUSIONS The series of experiments both in vitro and in vivo demonstrated that BM-MSCs can differentiate into functional odontoblast-like cells. This implies that BM-MSCs may become a novel source of cells for seeding in tooth regeneration research.
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Saeki K, Hilton JF, Alliston T, Habelitz S, Marshall SJ, Marshall GW, DenBesten P. Elevated TGF-beta2 signaling in dentin results in sex related enamel defects. Arch Oral Biol 2007; 52:814-21. [PMID: 17391645 PMCID: PMC2043093 DOI: 10.1016/j.archoralbio.2007.01.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2006] [Revised: 01/05/2007] [Accepted: 01/31/2007] [Indexed: 10/23/2022]
Abstract
UNLABELLED Initiation of enamel formation requires reciprocal signaling between epithelially and mesenchymally derived cells. OBJECTIVE In this study, we used a transgenic mouse model which drives overexpression of an activated form of TGF-beta2 under control of the osteocalcin promoter, to investigate the role of TGF-beta2 in the dental mesenchyme, on enamel formation. DESIGN Dentin and enamel were imaged by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Dentin mechanical properties were characterized for hardness and elasticity, following nanoindentation with a modified AFM. Pores found in enamel were quantified and compared using image analysis software (Scion Imagetrade mark). RESULTS The elastic modulus of dentin was significantly reduced in the male TGF-beta2 overexpressor mice as compared to male wildtype mice, with no significant differences between female mice. Similarly, there were significantly more pores in enamel of the male transgenic mice as compared to male wildtype mice, with no significant differences between female mice. In situ hybridization of the continuously erupting incisor confirmed that osteocalcin expression was limited to the odontoblast cell layer at all stages of tooth formation. CONCLUSION TGF-beta2 overexpression in the dentin matrix, results in sex-linked differences in dentin and enamel formation.
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Abstract
The dental pulp is a unique tissue and its importance in the long-term prognosis of the tooth is often ignored by clinicians. It is unique in that it resides in a rigid chamber which provides strong mechanical support and protection from the microbial rich oral environment. If this rigid shell loses its structural integrity, the pulp is under the threat of the adverse stimuli from the mouth, such as caries, cracks, fractures and open restoration margins, all of which provide pathways for micro-organisms and their toxins to enter the pulp. The pulp initially responds to irritation by becoming inflamed and, if left untreated, this will progress to pulp necrosis and infection. The inflammation will also spread to the surrounding alveolar bone and cause periapical pathosis. The magnitude of pulp-related problems should not be underestimated since their most serious consequence is oral sepsis, which can be life threatening, and hence correct diagnosis and management are essential. Clinicians must have a thorough understanding of the physiological and pathological features of the dental pulp as well as the biological consequences of treatment interventions.
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Huang GTJ, Shagramanova K, Chan SW. Formation of odontoblast-like cells from cultured human dental pulp cells on dentin in vitro. J Endod 2007; 32:1066-73. [PMID: 17055908 DOI: 10.1016/j.joen.2006.05.009] [Citation(s) in RCA: 134] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2006] [Revised: 05/15/2006] [Accepted: 05/17/2006] [Indexed: 01/09/2023]
Abstract
Recent characterization of human dental pulp stem cells has shed new light on the understanding of the odontoblastic lineage. The purpose of the study was to characterize human adult dental pulp cells isolated and cultured in vitro and to examine the cell differentiation potential grown on dentin. We observed that some pulp cells isolated with an enzyme-digestion approach proliferated at a similar rate as the immortal cell line NIH 3T3. Population doubling time (PDt) for pulp cells at passage 3 was 22.6 +/- 0.5 hours and for NIH 3T3 was 23.1 +/- 2.3 hours. The pulp cells formed mineral nodules stimulated with dexamethasone or dexamethasone plus 1,25-dihydroxyvitamin D3. Pulp cells, after being seeded onto mechanically and chemically treated dentin surface, appeared to establish an odontoblast-like morphology with a cytoplasmic process extending into a dentinal tubule revealed by scanning electron microscopy analysis. Our data demonstrated the formation of cells with odontoblastic morphologies on existing dentin, suggesting that isolated human pulp stem cells may differentiate into odontoblasts on dentin in vitro.
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Onyekwelu O, Seppala M, Zoupa M, Cobourne MT. Tooth development: 2. Regenerating Teeth in the Laboratory. ACTA ACUST UNITED AC 2007; 34:20-2, 25-6, 29. [PMID: 17348555 DOI: 10.12968/denu.2007.34.1.20] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Tooth loss can occur for a number of reasons and a variety of prosthetic tooth replacement solutions are available to the dental practitioner. This article discusses current approaches in the use of tissue engineering to replace teeth or repair dental tissues. These strategies will depend upon the manipulation of stem cells in the laboratory and, whilst much progress has recently been made, it is likely that successful human tooth regeneration is still some years ahead.
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Guven G, Gunhan O, Akbulut E, Cehreli ZC. Investigation of proliferative activity in the developing human tooth using Ki-67 immunostaining. Med Princ Pract 2007; 16:454-9. [PMID: 17917446 DOI: 10.1159/000107751] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2006] [Accepted: 02/18/2007] [Indexed: 12/30/2022] Open
Abstract
OBJECTIVE The aim of this study was to investigate the proliferation of the developing human tooth germ and its surrounding tissues using Ki-67 immunostaining. MATERIALS AND METHODS Sections of mandibular dental arch tissues collected from 4 cadaveric human fetuses of 13, 16, 21 and 30 weeks of gestation were used. The immunoreactivity of Ki-67 in the tissue sections was assessed visually under a light microscope. Immunohistochemical controls were performed by replacing the primary antibody with phosphate-buffered saline or normal rabbit lgG. RESULTS The control sections did not display Ki-67 immunoactivity. Specimens of 13 weeks of gestation revealed intense Ki-67 immunostaining throughout the entire developing mandibular primary molars. At 16 weeks of gestation, immunostaining was observed in the inner enamel epithelium and dental papilla, in conjunction with the dental lamina showing decreased immunostaining. At 21 weeks, Ki-67 immunostaining was observed only in the inner enamel epithelium and dental papilla. The immunoreactivity of active ameloblasts and odontoblasts decreased, along with the proliferation capacity of the dental lamina. At 30 weeks, both enamel and dentin formation was observed along the cusped aspect of the tooth germ. Ameloblasts and odontoblasts were no longer immunoreactive in this region, while both types of cells were immunoreactive at the cervical regions of the crown. Dental lamina cells showed disintegration and were totally Ki-67-negative at 30 weeks of gestation. CONCLUSION The Ki-67 immunoreactivity of the dental lamina decreased during intrauterine tooth development. Positive immunostaining was observed at specific sites in the enamel organ and dental papilla during the cap and bell stages.
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Nakashima M, Iohara K, Zheng L. Gene therapy for dentin regeneration with bone morphogenetic proteins. Curr Gene Ther 2006; 6:551-60. [PMID: 17073601 DOI: 10.2174/156652306778520665] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Recent advances in stem cell biology and gene therapy technology have provided the great potential of adult stem cells for therapeutic use in regeneration of lost tissue due to diseases including cancer, trauma, and even caries. Dental pulp tissues harbor mesenchymal stem/progenitor cells and have potential to regenerate and/or repair dentin-pulp complex after injury such as caries. There are two main methods, in vivo and ex vivo gene therapy. In in vivo gene therapy the healing potential of pulp tissue is enhanced by genes inducing dentin directly applied on the exposed/amputated dental pulp. In ex vivo gene therapy, pulp stem/progenitor cells transfected with some therapeutically proven genes to induce differentiation into odontoblasts which are transplanted on the exposed/amputated pulp. In the inflamed pulp under deep caries or trauma, possibly due to the limited supply of pulp stem/progenitor cells, it might be useful to apply cell-based ex vivo gene therapy compared to in vivo gene therapy. Before clinical use of ex vivo gene therapy for dentin regeneration in endodontics, there is a need for establishment of isolation, identification and expansion of the pulp stem cells. A safe and efficient gene delivery system also needs to be optimized. In this review we provide an overview of our current knowledge in the biology and function of adult pulp stem cells. This is followed by a discussion of the challenges of translating basic cellular and molecular biology of differentiation of pulp stem cells to safe and efficient gene therapy for dentin regeneration.
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Lu Y, Ye L, Yu S, Zhang S, Xie Y, McKee MD, Li Y, Kong J, Eick D, Dallas SL, Feng JQ. Rescue of odontogenesis in Dmp1-deficient mice by targeted re-expression of DMP1 reveals roles for DMP1 in early odontogenesis and dentin apposition in vivo. Dev Biol 2006; 303:191-201. [PMID: 17196192 PMCID: PMC2059935 DOI: 10.1016/j.ydbio.2006.11.001] [Citation(s) in RCA: 105] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2006] [Revised: 10/15/2006] [Accepted: 11/02/2006] [Indexed: 11/22/2022]
Abstract
Dentin matrix protein 1 (DMP1) is expressed in both pulp and odontoblast cells and deletion of the Dmp1 gene leads to defects in odontogenesis and mineralization. The goals of this study were to examine how DMP1 controls dentin mineralization and odontogenesis in vivo. Fluorochrome labeling of dentin in Dmp1-null mice showed a diffuse labeling pattern with a 3-fold reduction in dentin appositional rate compared to controls. Deletion of DMP1 was also associated with abnormalities in the dentinal tubule system and delayed formation of the third molar. Unlike the mineralization defect in Vitamin D receptor-null mice, the mineralization defect in Dmp1-null mice was not rescued by a high calcium and phosphate diet, suggesting a different effect of DMP1 on mineralization. Re-expression of Dmp1 in early and late odontoblasts under control of the Col1a1 promoter rescued the defects in mineralization as well as the defects in the dentinal tubules and third molar development. In contrast, re-expression of Dmp1 in mature odontoblasts, using the Dspp promoter, produced only a partial rescue of the mineralization defects. These data suggest that DMP1 is a key regulator of odontoblast differentiation, formation of the dentin tubular system and mineralization and its expression is required in both early and late odontoblasts for normal odontogenesis to proceed.
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Botero TM, Shelburne CE, Holland GR, Hanks CT, Nör JE. TLR4 Mediates LPS-Induced VEGF Expression in Odontoblasts. J Endod 2006; 32:951-5. [PMID: 16982271 DOI: 10.1016/j.joen.2006.03.018] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2006] [Revised: 03/10/2006] [Accepted: 03/17/2006] [Indexed: 11/20/2022]
Abstract
Lipopolysaccharide (LPS) from gram-negative bacteria cell walls such as Prevotella intermedia and Escherichia coli induce vascular endothelial growth factor (VEGF) expression in odontoblasts, but not in undifferentiated dental pulp cells. CD14 and TLR4 are responsible for LPS signaling in macrophages, but their expression levels and function in dental pulp cells are unknown. We showed here that murine odontoblast-like cells (MDPC-23) express CD14 and TLR4 by immunohistochemistry and flow cytometry. In contrast, undifferentiated dental pulp cells (OD-21) presented low or no expression of these two receptors. MDPC-23 cells showed CD14 and TLR4 up-regulation upon exposure to LPS, as determined by real time PCR. Dominant negative murine TLR4 (DN-mTLR4) transfected MDPC-23 cells did not show upregulated VEGF expression in response to LPS stimulation. These results demonstrate that odontoblast-like cells express CD14 and TLR4, and that LPS-induced VEGF expression is mediated, at least in part, by TLR4 signaling.
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Landini G. On dentinal innervation. Tissue Cell 2006; 38:277. [PMID: 16887161 DOI: 10.1016/j.tice.2006.06.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Ogawa R, Saito C, Jung HS, Ohshima H. Capacity of dental pulp differentiation after tooth transplantation. Cell Tissue Res 2006; 326:715-24. [PMID: 16865348 DOI: 10.1007/s00441-006-0242-0] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2006] [Accepted: 05/09/2006] [Indexed: 01/21/2023]
Abstract
Under pathological conditions, dental pulp elaborates both bone and dentin matrix in which the contribution of periodontal tissue cannot be excluded. This study has aimed to clarify the capability of dental pulp to deposit bone matrix in an auto-graft experiment by using (1) immunohistochemistry for 5-bromo-2'-deoxyuridine (BrdU) and nestin and (2) histochemistry for tartrate-resistant acid phosphatase (TRAP). Following the extraction of the molars of 3-week-old mice, the roots and pulp floor were resected and immediately transplanted into the sublingual region. On Days 5-7, tubular dentin formation commenced next to the pre-existing dentin at the pulp horn in which nestin-positive odontoblast-like cells were arranged. Up until Day 14, bone-like tissue formation occurred in the pulp chamber in which intense TRAP-positive cells appeared. These results suggest that odontoblast- and osteoblast-lineage cells reside in the dental pulp. Overall, specific dental pulp regeneration should provide fundamental knowledge for the realization of human tooth regeneration in the near future.
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Veerayutthwilai O, Luis NA, Crumpton RM, MacDonald GH, Byers MR. Peripherin- and CGRP-immunoreactive nerve fibers in rat molars have different locations and developmental timing. Arch Oral Biol 2006; 51:748-60. [PMID: 16720017 DOI: 10.1016/j.archoralbio.2006.03.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2005] [Revised: 03/10/2006] [Accepted: 03/16/2006] [Indexed: 10/24/2022]
Abstract
UNLABELLED Developing rat molars gain mature sensitivity to electric stimulation at 4-5 weeks after eruption, but the related mechanisms are incompletely understood. Preliminary studies showed weak co-localization of calcitonin gene-related peptide (CGRP) immunoreactivity (IR) with peripherin (PER) or neurofilament protein (NF) in rat molar nerve fibers, while the latter two co-localized extensively. OBJECTIVE Our goal was to compare timing and location of PER-IR and CGRP-IR innervation in rat first molars during tooth maturation. METHODS We used single and double immunocytochemistry to study molars of rats aged 10 days to 1 year. Neural patterns were compared with odontoblast maturation stages, dentinogenesis, formation of cell-free and cell-rich zones, and root closure. RESULTS Spatial and temporal patterns showed that most CGRP-IR and PER-IR have different terminal domains in teeth. PER-IR fibers were well established among immature odontoblasts prior to tooth eruption, but CGRP-IR fibers were absent. Two weeks after eruption of first molars, many CGRP-IR beaded fibers entered dentin, the larger PER-IR fibers began shifting away from odontoblasts towards the pulp, and the symmetrical PER-IR pulpal pattern was being established. The CGRP-IR fibers continued to increase their asymmetric dentinal innervation until root growth was completed, during which time odontoblasts matured, the cell-free and cell-rich zones appeared, and roots closed. CONCLUSIONS Sensory maturation of rat molars coincides with closed root apices, extensive innervation of dentin by CGRP-IR nerve fibers, and the appearance of the mature avascular odontoblast layer next to cell-free and cell-rich zones in the pulp horns.
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Murray PE, García-Godoy F. The outlook for implants and endodontics: a review of the tissue engineering strategies to create replacement teeth for patients. Dent Clin North Am 2006; 50:299-315, x. [PMID: 16530064 DOI: 10.1016/j.cden.2005.11.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Ideally, root canal therapy involves the removal of diseased pulp tissues and permanent replacement with healthy pulp to revitalize teeth. Rather than placing implants, the ideal solution is to grow new replacement teeth. Success rates of implants and endodontic treatments can exceed 90%, which presents a formidable challenge to tissue engineering researchers to ensure that future dental treatments are even more successful. The purpose of this article is to explain how tissue engineering can be used to create replacement teeth. The science of tissue engineering has evolved from growing simple tissues in cell culture incubators to a multistep process. Although the problems of introducing tissue engineering therapies as part of routine dental treatments are substantial, the potential benefits are equally ground breaking.
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Kumabe S, Nakatsuka M, Kim GS, Jue SS, Aikawa F, Shin JW, Iwai Y. Human dental pulp cell culture and cell transplantation with an alginate scaffold. Okajimas Folia Anat Jpn 2006; 82:147-55. [PMID: 16526573 DOI: 10.2535/ofaj.82.147] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Many studies on tissue stem cells have been conducted in the field of regenerative medicine, and some studies have indicated that cultured dental pulp mesenchymal cells secrete dentin matrix. In the present study we used alginate as a scaffold to transplant subcultured human dental pulp cells subcutaneously into the backs of nude mice. We found that when beta-glycerophosphate was added to the culture medium, dentin sialophosphoprotein mRNA coding dentin sialoprotein (DSP) was expressed. An increase in alkaline phosphatase, which is an early marker for odontoblast differentiation, was also demonstrated. At 6 weeks after implantation the subcutaneous formation of radio-opaque calcified bodies was observed in situ. Immunohistochemical and fine structure studies identified expression of type I collagen, type III collagen, and DSP in the mineralizing transplants. Isolated odontoblast-like cells initiated dentin-like hard tissue formation and scattered autolyzing apoptotic cells were also observed in the transplants. The study showed that subcultured dental pulp cells actively differentiate into odontoblast-like cells and induce calcification in an alginate scaffold.
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Ohazama A, Tucker A, Sharpe PT. Organized tooth-specific cellular differentiation stimulated by BMP4. J Dent Res 2005; 84:603-6. [PMID: 15972586 DOI: 10.1177/154405910508400704] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Mammalian teeth develop on the oral surface of the first pharyngeal arch by a series of reciprocal interactions between epithelial and mesenchymal cells. The embryonic first pharyngeal arch oral epithelium is able to induce tooth formation when combined with mesenchymal cells from the second pharyngeal arch, a region devoid of tooth development. Second pharyngeal arch mesenchyme is thus competent to form teeth if provided with the correct signals. First-arch oral epithelium expresses several signaling molecules that could be potential inducers of tooth development, including BMP4. The addition of BMP4 to intact second-arch explants resulted in the development of organized structures containing layers of cells that express marker genes of tooth-specific cells, odontoblasts and ameloblasts. Thus, although overt tooth development did not occur, BMP4 has the ability to stimulate organized differentiation of epithelial- and mesenchymal-derived dental-specific cells from non-dental primordia.
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Zhang W, Walboomers XF, Wolke JGC, Bian Z, Fan MW, Jansen JA. Differentiation ability of rat postnatal dental pulp cells in vitro. ACTA ACUST UNITED AC 2005; 11:357-68. [PMID: 15869416 DOI: 10.1089/ten.2005.11.357] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The current rapid progression in stem cell research has enhanced our knowledge of dental tissue regeneration. In this study, rat dental pulp cells were isolated and their differentiation ability was evaluated. First, dental pulp cells were obtained from maxillary incisors of male Wistar rats. Immunochemistry by stem cell marker STRO-1 proved the existence of stem cells or progenitors in the isolated cell population. The dissociated cells were then cultured both on smooth surfaces and on three-dimensional (3-D) scaffold materials in medium supplemented with beta-glycerophosphate, dexamethasone, and L-ascorbic acid. Cultures were analyzed by light and scanning electron microscopy and, on proliferation, alkaline phosphatase activity and calcium content were determined and the polymerase chain reaction was performed for dentin sialophosphoprotein, osteocalcin, and collagen type I. These cells showed the ability to differentiate into odontoblast-like cells and produced calcified nodules, which had components similar to dentin. In addition, we found that the "odontogenic" properties of the isolated cells were supported by three-dimensional calcium phosphate and titanium scaffolds equally well.
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Alliot-Licht B, Bluteau G, Magne D, Lopez-Cazaux S, Lieubeau B, Daculsi G, Guicheux J. Dexamethasone stimulates differentiation of odontoblast-like cells in human dental pulp cultures. Cell Tissue Res 2005; 321:391-400. [PMID: 15988617 DOI: 10.1007/s00441-005-1115-7] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2004] [Accepted: 03/08/2005] [Indexed: 01/09/2023]
Abstract
Regenerative dental pulp strategies require the identification of precursors able to differentiate into odontoblast-like cells that secrete reparative dentin after injury. Pericytes have the ability to give rise to osteoblasts, chondrocytes, and adipocytes, a feature that has led to the suggestion that odontoblast-like cells could derive from these perivascular cells. In order to gain new insights into this hypothesis, we investigated the effects of dexamethasone (Dex), a synthetic glucocorticoid employed to induce osteogenic differentiation in vitro, in a previously reported model of human dental pulp cultures containing pericytes as identified by their expression of smooth muscle actin (SMA) and their specific ultrastructural morphology. Our data indicated that Dex (10(-8) M) significantly inhibited cell proliferation and markedly reduced the proportion of SMA-positive cells. Conversely, Dex strongly stimulated alkaline phosphatase (ALP) activity and induced the expression of the transcript encoding the major odontoblastic marker, dentin sialophosphoprotein. Nevertheless, parathyroid hormone/parathyroid hormone-related peptide receptor, core-binding factor a1/osf 2, osteonectin, and lipoprotein lipase mRNA levels were not modified by Dex treatment. Dex also increased the proportion of cells expressing STRO-1, a marker of multipotential mesenchymal progenitor cells. These observations indicate that glucocorticoids regulate the commitment of progenitors derived from dental pulp cells to form odontoblast-like cells, while reducing the proportion of SMA-positive cells. These results provide new perspectives in deciphering the cellular and molecular mechanisms leading to reparative dentinogenesis.
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