Role of bone morphogenetic protein 1/tolloid proteinase family in the development of teeth and bone

骨形态发生蛋白（BMP）1/tolloid（TLD）蛋白酶家族是一类重要的基质金属蛋白酶,可通过调控细胞外基质的生物合成而在组织、器官生长发育中发挥重要作用。临床报道发现BMP1/TLD蛋白酶家族的编码基因发生突变可导致伴有成骨发育不全的Ⅰ型牙本质发育不全,提示该蛋白酶家族在牙及骨等硬组织发育中具有重要作用。本文将BMP1/TLD蛋白酶家族在牙和骨组织发育中的作用及其机制所取得的研究进展作一综述。     

骨形成蛋白2在牙本质再生组织工程中的研究进展

骨形成蛋白2(BMP2)对牙胚发育、形态发生及细胞外基质的分泌有重要的调控作用,并且能刺激间充质干细胞向成骨细胞、成软骨细胞及成牙本质细胞的分化。近年来国内外就BMP2在牙本质再生组织工程中的作用进行了广泛的研究。本文将BMP2在牙本质再生组织工程中的诱导作用、分子机制及临床应用前景作一综述。     

牙齿与骨形成蛋白(BMP)的关系

本文回顾总结了多年来对于牙本质的骨诱导性的研究发现及发展过程,以及这种骨诱导性与骨形成蛋白(BMP)的关系,从而提出了牙本质骨形成蛋白(DBMP)这一概念。发现DBMP在牙齿及其发育形成过程中都有一定量的分布,体内、外实验中,DBMP对牙乳头和牙髓中的未分化间充质细胞都具有诱导分化并形成牙本质或(和)骨样牙本质的作用,从而提出了牙齿发育中诱导分化的新设想及BMP在其中的作用,进一步提出了微环境学说在BMP诱导未分化间充质细胞分化中的作用及其意义。     

人牙乳头细胞内Smad5蛋白表达的免疫组化研究

目的：观察Smad5蛋白在体外原代培养的人牙乳头细胞内的表达及其在转化生长因子－β超家族信号转导中的作用。方法：原代培养的人牙乳头细胞，分别以骨形成蛋白－2（bone morphogenetic protein-2,BMP－2）和转化生长因子－β1（transforming growth factor－β1，TGF－β1）刺激，免疫组化检测Smad5的表达，图像分析仪半定量。结果：人牙乳头细胞（空白对照组）胞浆内可见Smad5阳性表达，胞核内未见阳性表达；BMP－2实验组胞核内Smad5强阳性表达，胞浆内为弱阳性表达；TGF－β1实验组细胞胞浆Smad5阳性，胞核未见表达。结论：人牙乳头细胞内存在Smad5的表达，Smad5能转导BMP－2信号至核内发挥作用，但不能TGF－β1信号，提示BMP－2在牙齿发育过程中信号传递可能是通过Smad5的信号途径实现的。     

骨形态发生蛋白信号通路在牙根发育中的作用

骨形态发生蛋白（BMP）家族是调节细胞生命活动的重要因子,几乎参与了所有组织的发育。BMP介导的信号通路在牙发育过程中发挥十分重要的作用,而牙根发育是牙发育的一部分,是上皮和间充质相互作用的复杂过程。上皮和牙胚间充质中的BMP信号通路在牙根发育中的作用也有所不同,本文综述了BMP信号通路在牙根发育中作用的研究进展。     

转化生长因子β1和骨形成蛋白2体外诱导成牙本质细胞分化

目的 观察转化生长因子β1（transforming growth factorβ1,TGF-β1）和骨形成蛋白2（bone morphogenetic protein2,BMP2)对体外培养的鼠牙乳头成牙本质细胞分化的影响。方法 取17d胎龄小鼠下颌第一磨牙牙胚，胰蛋白酶消化分离牙乳头，置半固态培养基培养6d，半固态培养基中加入重组TGF-β1或BMP2与肝素，组织学观察。结果 TGF-β1或BMP2加肝素可诱导牙乳头周边细胞发生极化，并分泌胞外基质。TGF-β1或BMP2单独加入时未见细胞极化，但基质分泌增加。结论 TGF-β1和BMP2均能诱导成牙本质细胞的细胞学分化和分泌功能。     

cbfa1反义核酸对体外培养小鼠牙胚发育的影响

目的：采用反义核酸技术，用特异的、与cbfa1 mRNA互补的AS—ODN，抑制cbfa1在体外培养牙胚的翻译，观察它对牙齿发育及矿化的影响，探讨其在牙齿发育中的作用。方法：设计合成cbfa1反义核酸，应用所建立的牙胚体外培养体系，用光镜和电镜观察小鼠牙胚被cbfa1反义核酸阻断表达后发育的情况。结果：在缺乏cbfa1情况下，与对照组相比，实验组牙胚在体外虽然可以继续生长发育至钟状晚期，但形成的基质较薄，且基质中胶原纤维排列稀疏，粗细不等，方向杂乱。此外，成釉细胞与成牙本质细胞的发育均显幼稚。结论：cbfa1可能不仅仅参与了牙齿的矿化，还在成牙本质细胞和成釉细胞的分化中起重要的作用。     

骨形成蛋白诱导异位成骨过程中细胞外基质的免疫组化研究

骨形成蛋白(BMP)诱导异位成骨是Urist等首先报告的,随着BMP分子生物学基因排序的进展,Wozney等现已将RMP1～8克隆化,其中,BMP-1具蛋白酶样结构,BMP2～8均属转化生长因子β(TGF-β)类,对细胞外基质(ECM)的成分如胶原(collagen)、     

金属蛋白酶解离素28在牙齿发育中的研究进展

金属蛋白酶解离素28（a disintegrin and metallo2 proteinase 28，ADAM28）是ADAM家族最近发现的一种分泌性糖蛋白，它同样具有ADAM家族的生理功能：参与细胞增殖，分化，胞外基质重建，裂解基质蛋白和细胞迁移等。研究显示，ADAM28基因参与了牙胚的发育过程，并在牙源性间充质细胞的增殖、分化和凋亡中发挥重要的调控作用。同时ADAM28基因具有金属蛋白酶活性，因而它对于细胞外基质的形成和蛋白的外功能区脱落有重要的调节作用。本文着重回顾了近年来国内外关于ADAM28生物学功能的研究及其在牙齿发育中的作用机制。     

大鼠正畸牙齿移动过程中Smad1的表达和意义

目的：探讨BMP超家族的细胞内信号转导分子Smad1蛋白在大鼠正畸牙齿移动过程中牙周组织的分布和表达。方法：用ABC免疫组织化学法，检测实验性大鼠正畸牙齿移动过程中牙周组织Smad1的表达。结果：Smad1在正畸牙齿加力各个时期存在的特异的分布模式，与BMP有相似之处。结论：Smad1参与了大鼠正畸牙齿移动过程，可能介导了BMP在正畸牙齿加力区的信号。     

Syndecan-1 and Wingless-type protein-1 in human ameloblastomas

BACKGROUND: Aberrant Wingless type 1 glycoprotein (Wnt) pathway in ameloblastomas and a role of syndecan-1 (SDC1) in activating Wnt signalling were perspected. SDC1 shifting from epithelium to stroma was reported in invasive non-odontogenic neoplasms. The aim of this study was to reveal the role of SDC1 and Wnt1 in intraosseous ameloblastomas (IA(s)). METHODS: SDC1 and Wnt1 expressions were investigated in 29 ameloblastoma subtypes and seven tooth buds. RESULTS: SDC1 immunostaining strongly depicted stromal cells, extracellular matrix (ECM) and basement membranes of ameloblastomas. It also showed epithelial tumour cells in the acanthomatous and plexiform subtypes, and it often occurred in stellate reticulum cells and basal ameloblasts of tooth buds. Parallel Wnt1 expression occurred in ameloblastomatous epithelial cells, but it was common in basal cells of tooth buds too. Statistically, a significant correlation was found between the percentage of IA(s)-bearing SDC1-positive stromal cells and ECM and the percentage of IA(s)-bearing Wnt1-positive epithelial cells. CONCLUSIONS: A role of SDC1 in stromal cells and ECM can be hypothesized as a critical factor for carcinogenesis and local invasiveness of IA(s).     

Collagen analysis in human tooth germ papillae

The extracellular matrix (ECM) performs a very important role in growth regulation and tissue differentiation and organization. In view of this, the purpose of this study was to analyze the collagen, the major organic component of dental pulp ECM, in papillae of human tooth germs in different developmental phases. The maxillas and mandibles of 9 human fetuses ranging from 10 to 22 weeks of intrauterine life were removed and 16 tooth germs (1 in the cap stage, 8 in the early bell stage and 7 in the late bell stage) were obtained. The pieces were processed for histological analysis and stained with hematoxylin-eosin, Masson's Trichrome and picrosirius staining technique. Both types of collagen in the dental papilla were only detected by the picrosirius staining technique under polarized light microscopy. Type III collagen was detected in all specimens. Type I collagen was present in focal areas of the dental papilla only in some specimens. In conclusion, the findings of this study showed that type III collagen is a regular component of the papillae of human tooth germs whereas type I collagen is present in a significantly lesser amount.     

Essential Roles of Bone Morphogenetic Protein-1 and Mammalian Tolloid-like 1 in Postnatal Root Dentin Formation

Introduction

Mutations in the proteinase bone morphogenetic protein-1 (BMP1) were recently identified in patients with osteogenesis imperfecta, which can be associated with type 1 dentinogenesis imperfecta. BMP1 is co-expressed in various tissues and has overlapping activities with the closely related proteinase mammalian tolloid-like 1 (TLL1). In this study we investigated whether removing the overlapping activities of BMP1 and TLL1 affects the mineralization of tooth root dentin.

cbfa1反义核酸对体外培养小鼠牙胚发育与矿化的影响

目的:采用反义核酸技术,用特异的与cbfa1mRNA互补的AS ODN抑制cbfa1在体外培养牙胚的翻译,利用电镜及ALP、OC等指标观察其对牙齿发育及矿化的影响,探讨其在牙齿发育中的作用。方法:设计合成cbfa1反义核酸,应用所建立的牙胚体外培养系统,用电镜观察小鼠牙胚被cbfa1反义核酸阻断表达后发育的情况,并且检测ALP、OC表达量的变化。结果:在缺乏cbfa1的情况下,与对照组相比,形成的基质较薄,且基质中胶原纤维排列稀疏,粗细不等,方向杂乱,ALP、OC表达量均有明显变化。结论:cbfa1可能是通过调控ALP和OC等靶基因的表达参与了牙齿发育矿化过程。     

牙胚细胞与骨形态发生蛋白4转染的骨髓间充质干细胞相互诱导的体外实验研究

目的:探讨牙胚细胞和骨形态发生蛋白4(BMP4)转染的骨髓间充质干细胞(BMSCs)相互间的成牙诱导作用。方法:构建骨形态发生蛋白4慢病毒载体,转染SD大鼠骨髓间充质干细胞,并将骨髓间充质干细胞和BMP4转染的骨髓间充质干细胞分别与SD大鼠牙胚细胞按1∶1比例混合培养,同时将细胞分为5组,BMSCs组、BMP4/ BMSCs组、牙胚细胞组、BMSCs/牙胚细胞组(混合组1)、BMP4/ BMSCs/牙胚细胞组(混合组2),分别采用实时荧光定量PCR和western-blotting检测五组细胞Ⅰ型胶原蛋白、成釉蛋白、牙本质基质蛋白1、同源异型盒基因1成牙相关基因mRNA水平和蛋白水平相对表达量的变化。结果:与混合组1相比,混合组2Ⅰ型胶原蛋白、成釉蛋白、牙本质基质蛋白1、同源异型盒基因1 mRNA水平和蛋白水平表达量增多,差异有统计学意义(P<0.05)。结论:牙胚细胞与BMP4转染的骨髓间充质干细胞共培养,促进了成牙相关基因的表达,可作为组织工程牙的备选种子细胞。     

Enhancing cell seeding and osteogenesis of MSCs on 3D printed scaffolds through injectable BMP2 immobilized ECM-Mimetic gel

ObjectiveDesign of bioactive scaffolds with osteogenic capacity is a central challenge in cell-based patient-specific bone tissue engineering. Efficient and spatially uniform seeding of (stem) cells onto such constructs is vital to attain functional tissues. Herein we developed heparin functionalized collagen gels supported by 3D printed bioceramic scaffolds, as bone extracellular matrix (ECM)-mimetic matrices. These matrices were designed to enhance cell seeding efficiency of mesenchymal stem cells (MSCs) as well as improve their osteogenic differentiation through immobilized bone morphogenic protein 2 (BMP2) to be used for personalized bone regeneration.MethodsA 3D gel based on heparin-conjugated collagen matrix capable of immobilizing recombinant human bone morphogenic protein 2 (BMP2) was synthesized. Isolated dental pulp Mesenchymal stem cells (MSCs) were then encapsulated into the bone ECM microenvironment to efficiently and uniformly seed a bioactive ceramic-based scaffold fabricated using additive manufacturing technique. The designed 3D cell-laden constructs were comprehensively investigated trough in vitro assays and in vivo study.ResultsIn-depth rheological characterizations of heparin-conjugated collagen gel revealed that elasticity of the matrix is significantly improved compared with freely incorporated heparin. Investigation of the MSCs laden collagen-heparin hydrogels revealed their capability to provide spatiotemporal bioavailability of BMP2 while suppressing the matrix contraction over time. The in vivo histology and real-time polymerase chain reaction (qPCR) analysis showed that the designed construct supported the osteogenic differentiation of MSCs and induced the ectopic bone formation in rat model.SignificanceThe presented hybrid constructs combine bone ECM chemical cues with mechanical function providing an ideal 3D microenvironment for patient-specific bone tissue engineering and cell therapy applications. The implemented methodology in design of ECM-mimetic 3D matrix capable of immobilizing BMP2 to improve seeding efficiency of customized scaffolds can be exploited for other bioactive molecules.     

Roles of Membrane-type 1 Matrix Metalloproteinase in Tumor Invasion and Progression

Membrane-type 1 matrix metalloproteinase (MT1-MMP) has been implicated in tumor invasion and metastasis. Degradation of the extracellular matrix (ECM) and cell migration are critical steps in tumor invasion. MT1-MMP stimulates a cascade for ECM degradation on the surface of tumor cells, and promotes cell migration and focal adhesion turnover by activating extracellular signal-regulated kinase (ERK) and by processing various biologically important cell-surface molecules. Moreover, MT1-MMP promotes tumor cell proliferation in the 3-dimensional (3-D) ECM but not in 2-D ECM culture system. Studying the biological function of MT1-MMP would appear to be important for better understanding of the mechanisms of tumor invasion and progression.     

Nel样1型分子对成骨细胞分化的分子调控机制

Nel样1型分子(Nell-1)是一种新的重要的生长因子,其基因主要在成骨细胞的分化和程序性死亡阶段发挥重要的作用。下面着重就nell-1基因与转化生长因子和成纤维细胞生长因子,nell-1基因在介导成骨细胞分化过程中的作用和相关分子信号途径,Nell-1蛋白对成骨细胞和成软骨细胞胞外基质蛋白的调控作用等作一综述。