Effects of Alginate Hydrogels and TGF-β1 on Human Dental Pulp Repair In Vitro

The objective of this study was to investigate the use of alginate hydrogels to present either exogenous or endogenous transforming growth factor (TGF)- &#103 1 to the dentin-pulp complex to signal reparative processes. Hydrogels were prepared, applied to cultured human tooth slices and the effects on tertiary dentinogenesis examined histologically. Both TGF- &#103 1-containing and acid-treated alginate hydrogels, but not untreated hydrogels, upregulated dentin matrix secretion and induced odontoblast-like cell differentiation with subsequent secretion of regular tubular dentin matrix on cut pulpal surfaces. It is concluded that TGF- &#103 1 can signal both induction of odontoblast-like cell differentiation and upregulation of their matrix secretion in the human dentin-pulp complex. Alginate hydrogels provide an appropriate matrix in which dental regeneration can take place and may also be useful for delivery of growth factors, including TGF- &#103 s, to enhance the natural regenerative capacity of the dental pulp.     

Human dental pulp cell culture and cell transplantation with an alginate scaffold

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.     

Isolated rat dental pulp cell culture and transplantation with an alginate scaffold

Many studies have been conducted on tissue stem cells in the field of regenerative medicine, and cultured dental pulp mesenchymal cells have been reported to secrete dentin matrix. In the present study we used alginate as a scaffold to transplant subcultured rat dental-pulp-derived cells subcutaneously into the back of nude mice. We found that when beta-glycerophosphate was added to the culture medium, the mRNA of the dentin sialophosphoprotein (DSPP) gene coding dentin sialoprotein (DSP) and dentin phosphoprotein (DPP) was expressed, and an increase in alkaline phosphatase, an early marker of odontoblast differentiation, was also demonstrated. Six weeks after implantation, subcutaneous formation of radiopaque 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, and isolated odontoblast-like cells began to form dentin-like hard tissue formation. Scattered autolyzing apoptotic cells were also observed in the transplants. The study showed that subcultured rat dental-pulp-derived cells actively differentiate into odontoblast-like cells and induce calcification in an alginate scaffold.     

A histochemical study of the regeneration process after injury by pulsed Nd:YAG laser irradiation of root canals

Histological changes of rat dental pulp cells were followed after injury. The regeneration process after 3, 6 and 10 days was monitored. Mandibular incisors were irradiated with a pulsed Nd:YAG laser at 2 W and 20 pulses per sec (pps) for 5 sec and the pulp was examined histologically and immunohistochemically for TGF-beta1. Eruption of the developing tooth was disturbed for a short period only. Rapid formation of osteodentin was observed. After 3 days, a zone of fibrodentin matrix as well as newly formed vessels were found. Afterwards, regenerative dentin formation was observed accompanied by the formation of a layer of odontoblast-like cells in the damaged area. Immunohistochemical staining of TGF-beta1 showed that positivity was present in small tissue areas beneath the mantle dentin, the zone of fibrodentin matrix and odontoblast-like cells. These results indicate that pulsed Nd:YAG laser irradiation of rat incisor pulp induces formation of osteodentin, and TGF-beta1 plays a role during regeneration.     

Natural mineralized scaffolds promote the dentinogenic potential of dental pulp stem cells via the mitogen-activated protein kinase signaling pathway

The selection of a suitable scaffold material is important for dentin tissue regeneration, as the characteristics of biomaterials can potentially influence cell proliferation and differentiation. We compared the effects of different scaffolds on dentin regeneration based on dental pulp stem cells (DPSCs) and investigated the regulatory mechanisms of odontogenic differentiation of DPSCs by these scaffolds. Five different scaffolds were tested: demineralized dentin matrix (DDM), ceramic bovine bone (CBB), small intestinal submucosa (SIS), poly-L-lactate-co-glycolate, and collagen-chondroitin sulfate-hyaluronic acid. DPSCs cultured on DDM and CBB exhibited higher levels of alkaline phosphatase (ALP) activity and mRNA expression of bone sialoprotein, osteocalcin, dentin sialophosphoprotein (DSPP), and dentin matrix protein-1 (DMP-1) than those cultured on the other three scaffolds. Further, the phosphorylation levels of mitogen-activated protein kinase (MAPK) ERK1/2 and p38 in DPSCs cultured on DDM and CBB were also significantly enhanced compared with the other three scaffolds, and their inhibitors significantly inhibited odontogenic differentiation as assessed by ALP activity and mRNA expression of DSPP and DMP-1. The implantation experiment confirmed these results and showed a large amount of regular-shaped dentin-pulp complex tissues, including dentin, predentin, and odontoblasts only in the DDM and CBB groups. The results indicated that natural mineralized scaffolds (DDM and CBB) have potential as attractive scaffolds for dentin tissue-engineering-promoted odontogenic differentiation of DPSCs through the MAPK signaling pathway.     

Differential response of adult and embryonic mesenchymal progenitor cells to mechanical compression in hydrogels

Cells in the musculoskeletal system can respond to mechanical stimuli, supporting tissue homeostasis and remodeling. Recent studies have suggested that mechanical stimulation also influences the differentiation of MSCs, whereas the effect on embryonic cells is still largely unknown. In this study, we evaluated the influence of dynamic mechanical compression on chondrogenesis of bone marrow-derived MSCs and embryonic stem cell-derived (human embryoid body-derived [hEBd]) cells encapsulated in hydrogels and cultured with or without transforming growth factor beta-1 (TGF-beta1). Cells were cultured in hydrogels for up to 3 weeks and exposed daily to compression for 1, 2, 2.5, and 4 hours in a bioreactor. When MSCs were cultured, mechanical stimulation quantitatively increased gene expression of cartilage-related markers, Sox-9, type II collagen, and aggrecan independently from the presence of TGF-beta1. Extracellular matrix secretion into the hydrogels was also enhanced. When hEBd cells were cultured without TGF-beta1, mechanical compression inhibited their differentiation as determined by significant downregulation of cartilage-specific genes. However, after initiation of chondrogenic differentiation by administration of TGF-beta1, the hEBd cells quantitatively increased expression of cartilage-specific genes when exposed to mechanical compression, similar to the bone marrow-derived MSCs. Therefore, when appropriately directed into the chondrogenic lineage, mechanical stimulation is beneficial for further differentiation of stem cell tissue engineered constructs.     

儿童乳牙牙髓干细胞顺硬度基质表面延展和向牙本质分化的潜能

文题释义： 组织相容性：是一组被称为人类白细胞抗原(HLA)的基因具有相同或足够相似的等位基因的特性。与整个器官、组织或干细胞移植有关的主题最相关。人类6号染色体6p21.3处每个HLA位点存在大量等位基因,这些基因是共显性表达的,意味着每个个体都表达每个遗传的等位基因,包括父系和母系,导致每个个体都有不同类型的MHC蛋白的混合物。一个人的HLA等位基因的相似或差异,以及MHC蛋白与另一个人的相似或不同,是使组织相容或不相容的原因。 牙髓干细胞：2000年GRONTHOS等发现一种与骨髓间充质干细胞有着相似的免疫表型及形成矿化结节能力的梭形成纤维状细胞。这类细胞可自我更新和多向分化,并有着较强的克隆能力,经过不同细胞因子的诱导,能够分化为脂肪、骨、软骨、肌肉、血管内皮、肝、神经等细胞系类型,在牙组织工程中具有重要研究价值。 背景：牙髓干细胞在适宜诱导条件下能够向牙本质分化,是牙齿组织工程的重要种子细胞。然而,以往所使用的诱导剂多为化学制剂,不利于体内应用。近来有报道称间充质干细胞能够顺材质硬度分化,这种由物理特性诱导的细胞分化研究报道较少。 目的：观察人源性乳牙牙髓干细胞在硬介质表面的延展特点及向牙本质分化潜能,为牙组织工程提供参考。 方法：原代分离培养和鉴定儿童自然脱落的乳牙牙髓干细胞;使用低熔点琼脂糖配制弹性模量为(9.12±0.94),(27.18±3.55),(59.37±4.05)和(86.45±5.33) kPa 4个梯度的固体凝胶基质,二维克隆形成实验和划痕实验检测第4代乳牙牙髓干细胞在上述硬基质表面的延展能力,Western blot方法检测牙本质基质蛋白1、牙本质磷蛋白、牙本质涎蛋白的表达。 结果与结论：当人乳牙牙髓干细胞接种于极低和低等硬度凝胶介质表面时,乳牙牙髓干细胞几乎均以边缘整齐的细胞克隆存在,很少见细胞平铺和延展现象;但是当将其接种于中等和高等硬度凝胶介质表面时,乳牙牙髓干细胞克隆边缘则表现出明显的平铺和延展,表现为细胞胞体变大,细胞边缘外伸明显。相似的现象也经细胞划痕实验所验证。人源性乳牙牙髓干细胞在中等和高等弹性模量介质表面培养时,表达较高水平的牙本质基质蛋白1、牙本质磷蛋白、牙本质涎蛋白。结果表明,人源性乳牙牙髓干细胞随着培养基质硬度的增加其延展性及成牙本质分化能力逐渐增强,为未来牙组织工程提供方法借鉴。 ORCID: 0000-0002-5640-4472(刘晓智) 中国组织工程研究杂志出版内容重点：干细胞;骨髓干细胞;造血干细胞;脂肪干细胞;肿瘤干细胞;胚胎干细胞;脐带脐血干细胞;干细胞诱导;干细胞分化;组织工程     

Influence of Substrate Nature and Immobilization of Implanted Dentin Matrix Components During Induction of Reparative Dentinogenesis

The biological effects of isolated soluble dentin extracellular matrix components on the induction of reparative dentinogenesis in exposed cavities in ferret canine teeth have been shown to be blocked by immobilizing the extracellular matrix components on nitrocellulose or Millipore membranes during implantation. This contrasts with the picture of induction of odontoblast-like cell differentiation and reparative dentin deposition on existing insoluble dentin matrix of the exposure walls when the extracellular matrix components are implanted in lyophilized form. These data indicate the importance of an existing insoluble dentin matrix in providing a substrate to potentiate the growth factor-like activity of soluble isolated dentin extracellular matrix components in the induction of reparative dentinogenesis.     

Cryopreserved dentin matrix as a scaffold material for dentin-pulp tissue regeneration

Cryopreservation has been identified as an efficient approach to preserve tissue engineered products for a long term. Our prior studies have suggested that the treated dentin matrix (TDM) could be an ideal bioactive scaffold for dental tissue regeneration. In this study, we hypothesize that the cryopreservation could effectively maintain the survival and viability of dentinogenesis-related proteins of TDM and the cryopreserved dentin matrix (CDM) would provide the suitable biological scaffold and inductive microenvironment for the regeneration of dentin-pulp like tissue. CDM-3 and CDM-6 were prepared by cryopreserving TDM in liquid nitrogen (−196 °C) with cryoprotectant for 3 months and 6 months, respectively. Various biological characteristics of CDM, including mechanical properties, cell proliferation, and odontogenesis ability, were investigated. To further evaluate the inductive capacity of CDM, human dental follicle cells were encapsulated within CDM, and implanted the scaffold into a mouse model for 8 weeks, and the grafts were harvested and assessed histologically. The CDM showed superior mechanical properties than TDM. Compared to TDM, CDM can release more dentinogenesis-related proteins due to the larger pore diameter. Cell proliferation with the addition of CDM extract liquid was similar to that of TDM in the first five days. Human dental follicle cells, under the effect of CDM extract liquid, highly expressed bone sialoprotein, collagen-1, alkaline phosphatase, indicating that CDM, regarded as the inductive microenvironment, plays an important role in odontogenesis. Most importantly, in vivo, CDM could induce dental follicle cells to regenerate new dentin-pulp like tissues, such as dentinal tubules, predentin, collagen fibers, nerves, and blood vessels which were positive for dentin sialophosphoprotein, dental matrix protein-1, Tubulin, and collagen-1. In conclusion, CDM is an ideal biological scaffold material for human dentin-pulp like tissue regeneration. These findings indicated that TDM could be preserved as the tissue engineering scaffold that is readily available for patient treatments. Furthermore, the success of cryopreservation of TDM may also provide an insight into preserving other bioactive scaffold materials of tissue engineering.     

Differentiation of dental pulp stem cells into regular-shaped dentin-pulp complex induced by tooth germ cell conditioned medium

Investigations of the odontoblast phenotype are hindered by obstacles such as the limited number of odontoblasts within the dental pulp and the difficulty in purification of these cells. Therefore, it is necessary to develop a cell culture system in which the local environment is inductive and can promote dental pulp stem cells (DPSCs) to differentiate into odontoblast lineage. In this study, we investigated the effect of conditioned medium from developing tooth germ cells (TGCs) on the differentiation and dentinogenesis of DPSCs both in vitro and in vivo. DPSCs were enzymatically isolated from the lower incisors of 4-week-old Sprague-Dawley rats and co-cultured with TGC conditioned medium (TGC-CM). The cell phenotype of induced DPSCs presents many features of odontoblasts, as assessed by the morphologic appearance, cell cycle modification, increased alkaline phosphatase level, synthesis of dentin sialoprotein, type I collagen and several other noncollagenous proteins, expression of the dentin sialophosphoprotein and dentin matrix protein 1 genes, and the formation of mineralized nodules in vitro. The induced DPSC pellets in vivo generated a regular-shaped dentin-pulp complex containing distinct dentinal tubules and predentin, while untreated pellets spontaneously differentiated into bone-like tissues. To our knowledge, this is the first study to mimic the dentinogenic microenvironment from TGCs in vitro, and our data suggest that TGC-CM creates the most odontogenic microenvironment, a feature essential and effective for the regular dentinogenesis mediated by DPSCs.     

Hydrogel effects on bone marrow stromal cell response to chondrogenic growth factors

The aim of this study was to investigate the effects of alginate and agarose on the response of bone marrow stromal cells (BMSCs) to chondrogenic stimuli. Rat BMSCs were expanded in monolayer culture with or without FGF-2 supplementation. Cells were then seeded in 2% alginate and agarose gels and cultured in media with or without TGF-beta1 or dexamethasone (Dex). Sulfated glycosaminoglycans (sGAGs), collagen type II, and aggrecan were expressed in all groups that received TGF-beta1 treatment during hydrogel culture. Expansion of rat BMSCs in the presence of FGF-2 increased production of sGAG in TGF-beta1-treated groups over those cultures that were treated with TGF-beta1 alone in alginate cultures. However, in agarose, cells exposed to FGF-2 during expansion produced less sGAG within TGF-beta1-supplemented groups over those cultures treated with TGF-beta1 alone. Dex was required for optimal matrix synthesis in both hydrogels, but was found to decrease cell viability in agarose constructs. These results indicate that the response of BMSCs to a chondrogenic growth factor regimen is scaffold dependent.     

A Journey from Dental Pulp Stem Cells to a Bio-tooth

The ultimate goal of tooth regeneration is to replace the lost teeth. Stem cell-based tooth engineering is deemed as a promising approach to the making of a biological tooth (bio-tooth). Dental pulp stem cells (DPSCs) represent a kind of adult cell colony which has the potent capacity of self-renewing and multilineage differentiation. The exact origin of DPSCs has not been fully determined and these stem cells seem to be the source of odontoblasts that contribute to the formation of dentin-pulp complex. Recently, achievements obtained from stem cell biology and tooth regeneration have enabled us to contemplate the potential applications of DPSCs. Some studies have proved that DPSCs are capable of producing dental tissues in vivo including dentin, pulp, and crown-like structures. Whereas other investigations have shown that these stem cells can bring about the formation of bone-like tissues. Theoretically, a bio-tooth made from autogenous DPSCs should be the best choice for clinical tooth reconstruction. This review will focus on the location, origin, and current isolation approaches of these stem cells. Their odontoblastic differentiation and potential utilizations in the reconstruction of dentin-pulp complex and bio-tooth will be extensively discussed.     

Odontogenic differentiation and dentin formation of dental pulp cells under nanobioactive glass induction

Bioactive glass (BG) has been widely used in bone regeneration; however, reports on the biological effects of BG on dental pulp cells are rare. This study aims to investigate the effects of nanoscale BG (n-BG) on odontogenic differentiation and dentin formation of dental pulp cells and to compare these effects with those of microscale BG (m-BG). Human dental pulp cells (hDPCs) from third molars were cultured directly with m-BG and n-BG in vitro. The cell proliferation increased at 0.1 mg ml⁻¹ BG, which also had a chemotactic effect on hDPCs. The mineralization capacity and expression of odontogenic-related proteins and genes (dentin sialophosphoprotein, dentin matrix protein 1 and collagen type I) of hDPCs were significantly up-regulated under BG induction, and were particularly higher in the n-BG group than in the control group. m-BG and n-BG combined with pulp tissues were transplanted into the dorsum of immunodeficient mice to observe their biological effects on dental pulp cells in vivo. A continuous layer of dentin-like tissue with uniform thickness, a well-organized dentinal tubule structure and polarizing odontoblast-like cells aligned along it was generated upon the n-BG layer, whereas some irregular sporadic osteodentin-like mineralized tissues were observed in the control group. This study reveals that BG, especially n-BG, induces the odontogenic differentiation and dentin formation of dental pulp cells and may serve as a potential material for pulp repair and dentin regeneration.     

Induction of Reparative Dentinogenesis In Vivo: A Synthesis of Experimental Observations

EDTA—and/or guanidine HCl—insoluble dentinal matrix, or demineralized dentin which had been treated with plasma fibronectin, or pieces of Millipore filters coated with a recombinant fibronectin-like engineered polymer, incorporating many RGD sequences, were implanted into central parenchymal sites of young dog molars, via mechanical pulp exposures. Furthermore demineralized dentin and Millipore filters coated with plasma ribronectin were placed into the central pulp of old animals. Histological analysis of buffered formalin-fixed tissues showed that: 1. The dentinogenic activity was retained in the EDTA—and/or guanidine-insoluble dentin matrix. 2. Implantation of Millipore filters supplemented with the recombinant polymer did not induce any odontoblast-like cell differentiation, indicating that the interactions of pulp cells with the exogenous ribronectin are not RGD-dependent. 3. Acid-insoluble dentin matrix or plasma ribronectin (both separately inducing dentinogenesis in dental pulp of young animals) did not show any dentinogenic activity when exposed in pulp sites of old animals. Acid-insoluble dentin matrix and plasma ribronectin also failed to induce dentinogenic activity in the young pulpal tissues, when both factors were combined before to their implantation. Synthesizing the present data with previous relevant information it could be suggested that in the mechanism initiating reparative dentinogenesis. Growth factors (endogenous or artificially implanted) and ribronectin are involved and this mechanism seems to be more complex than the simple immobilization of pulp cells onto an adhesion substratum.     

Odontogenic differentiation of human dental pulp stem cells induced by preameloblast-derived factors

The differentiation of odontoblasts is initiated by the organization of differentiating ameloblasts during tooth formation. However, the exact roles of ameloblast-derived factors in odontoblast differentiation have not yet been characterized. We investigated the effects of preameloblast-conditioned medium (PA-CM) on the odontogenic differentiation of human dental pulp stem cells (hDPSCs) in?vitro and in?vivo. Furthermore, we analyzed the PA-CM by liquid chromatography-mass spectrometry to identify novel factors that facilitate odontoblast differentiation. In the co-culture of MDPC-23 cells or hDPSCs with mouse apical bud cells (ABCs), ABCs promoted differentiation of odontoblastic MDPC-23 cells and facilitated odontoblast differentiation of hDPSCs. PA-CM, CM from ABCs after 3 days culture, was most effective in increasing the dentin sialophosphoprotein promoter activity of odontoblastic MDPC-23 cells. When PA-CM-treated hDPSCs were transplanted into immunocompromised mice, they generated pulp-like structures lined with human odontoblast-like cells showing typical odontoblast processes. However, during recombinant human bone morphogenenetic protein 2-treated hDPSCs transplantation, some of the cells were entrapped in mineralized matrix possessing osteocyte characteristics. After proteomic analyses, we identified 113 types of proteins in PA-CM, of which we characterized 23. The results show that preameloblast-derived factors induce the odontogenic differentiation of hDPSCs and promote dentin formation.     

Performance of electrospun poly(ε-caprolactone) fiber meshes used with mineral trioxide aggregates in a pulp capping procedure

Living dental pulp tissue exposed to the oral environment should be protected with an appropriate pulp capping material to support the dentinogenesis potential of the pulp cells. Mineral trioxide aggregate (MTA) is the material of choice for the treatment of pulp. However, due to cytotoxicity during the initial setting phase of MTA, a new material is required that can act as a barrier to direct contact but facilitate the favorable effect of MTA. This study examined the feasibility of using electrospun poly(ε-caprolactone) fiber (PCL-F) meshes in the MTA-based pulp capping procedures. An experimental pulp capping was performed on the premolars of beagle dogs, and the efficacy of the PCL-F meshes was evaluated after 8 weeks. PCL-F/MTA formed a dentin bridge that was approximately fourfold thicker than that formed by the MTA. Columnar polarized odontoblast-like cells with long processes and tubular dentin-like matrices were observed beneath the dentin bridge in the PCL-F/MTA. The cells were also intensely immunostained for dentin sialoprotein. In cell cultures, PCL-F/MTA reduced cell death to ~8% of that in the MTA group. The proliferation of the cells cultured on PCL-F/MTA was much greater than that of cells cultured on MTA. Furthermore, PCL-F/MTA promoted the differentiation of MDPC23 cells to odontoblast-like cells and biomineralization, as confirmed by the expression of alkaline phosphatase and dentin sialophosphoprotein, and by the deposition of calcium. Based on these histologic findings and the cell responses observed in this study, PCL-F may be used efficiently in the MTA-based dental pulp therapy.     

Differential expression of TGF-beta isoforms during differentiation of HaCaT human keratinocyte cells: implication for the separate role in epidermal differentiation

The three mammalian isoforms of transforming growth factor-beta(TGF-beta1, beta2, beta3) are potent regulators of cell growth, differentiation, and extracellular matrix deposition. To study their role in skin differentiation, we investigated the expression of TGF-beta isoforms on cell growth and differentiation induction of the human keratinocyte cell line, HaCaT by elevating the Ca(2+) concentration. An ELISA and RT-PCR assay revealed secreted TGF-beta 1 protein and TGF-beta 1 mRNA were increased during calcium-induced differentiation. In contrast, major differences were seen for TGF-beta 2 and TGF-beta 3 mRNA which were decreased during differentiation, but TGF-beta 2 and TGF-beta3 protein were not evident on an ELISA. These results suggest different functions for each TGF-beta isoforms in epidermal differentiation, such that TGF-beta 1 is associated with the more differentiated state, and TGF-beta 2 and TGF-beta 3 may be associated the more proliferated state.     

Differentiation ability of rat postnatal dental pulp cells in vitro

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.     

TGF-beta latency-associated peptides (LAPs) in human dentin matrix and pulp

Transforming growth factor (TGF)-beta s in dentin matrix provide a pool of bioactive molecules, but association with latency-associated peptides (LAPs) may influence their activity. We investigated TGF-beta 1, -beta 2, and -beta 3 LAP expression in sound and carious human teeth. Teeth were fixed and processed immediately following extraction prior to staining with rabbit polyclonal antibodies to the TGF-beta LAPs. A soluble dentin matrix fraction was prepared from dissected human dentin and sequential extraction of pulpal ECM was performed prior to purification. Fractions were Western blotted and probed with the LAP antibodies. All three LAPs were present in odontoblasts, cells of the pulp, and predentin; however, no staining of mineralized dentin matrix was seen. Similar patterns of expression were seen in carious tissue. Expression of TGF-beta LAPs in cells and pulpal matrix of healthy and carious teeth will be important in regulation of TGF-beta activity and may modulate the tissue response to injury.