特异性多能转录因子及其作用的研究进展

将自胚胎干细胞中筛选出的oct-4、sox一2、c-mye、klf-4四种基因组合转入体细胞,可获得与胚胎干细胞类似的诱导性多能干细胞.牙髓干细胞取材简单,尝试利用特异性多能转录因子将其重编程为与胚胎干细胞类似的诱导性多能干细胞,可为牙组织工程提供优质的种子细胞.本文就特异性多能转录因子的结构和功能、在体细胞去分化中的...     

诱导性多能干细胞在牙周组织重建领域的应用进展

把特定的细胞因子负载到病毒上,再导入成熟体细胞,可将已分化的细胞重编程为诱导性多能干细胞(Induced pluripotent stem cells,iPS cells),iPS细胞能够快速增殖同时长期保持未分化状态,并可被诱导形成多种成熟体细胞、组织及器官。可通过组织工程的方法,将iPS细胞与特定细胞因子联合培养,与合适的细胞支架结合,通过细胞的增殖、分化、矿化沉淀,启动成骨及成血管过程,修复缺损的牙周组织。本文对iPS细胞的来源、培养方法,组织工程相关的细胞因子、细胞支架,及iPS细胞在牙周组织重建领域的应用进展作一系统综述。     

低氧对人牙囊细胞生物学特性的影响

目的 研究低氧对人牙囊细胞（hDFCs）生物学特性的影响。方法 利用组织块酶消化法从年轻恒牙中分离培养hDFCs;采用免疫荧光技术检测细胞表面标志物,多向诱导实验检测细胞多向分化潜能;模拟体外低氧微环境,将细胞分为常氧组（20%O₂）和低氧组（2%O₂）,分别对两组细胞行Transwell小室试验检测低氧对细胞迁移的影响,采用CCK-8法检测低氧对细胞增殖的影响。通过实时定量聚合酶链反应（qRT-PCR）和Western blot分别从基因和蛋白水平检测hDFCs多能性相关标志物于不同氧体积分数下的表达;分别对两组细胞进行成骨诱导,qRT-PCR检测成骨相关基因,茜素红染色评估矿化结节的形成。结果 hDFCs具有较强的干细胞特征,具有成骨、成脂及成神经多向分化能力,符合间充质干细胞基本标准,能够满足牙组织工程构建对种子细胞的需求。低氧有利于hDFCs多能性的保持,同时促进了hDFCs的迁移和增殖。hDFCs于低氧中进行诱导时,其成骨分化能力得到增强。结论 低氧微环境对维持hDFCs多能性,促进hDFCs增殖、迁移和分化有重要作用。     

猪牙胚细胞条件培养基可诱导人牙髓干细胞的牙向分化

牙源性干细胞的分化受其所处的局部微环境所调控。以往研究表明牙胚细胞条件培养基可诱导牙髓干细胞向成牙的细胞谱系分化。然而，采用人牙胚细胞条件培养基诱导在实际操作中不可行，所以推测异种的牙胚细胞条件培养基可能对人牙髓干细胞产生类似的效应。本研究采用猪的牙胚细胞条件培养基（pTGC-cM）来诱导人牙髓干细胞，评估其诱导前后的细胞形态学、集落形成、体外多向分化、与成牙相关的蛋白和基因表达、体内分化能力等。     

代谢重编程在间充质干细胞功能调控中的作用及机制

间充质干细胞(MSCs)是一类具有自我更新和多向分化潜能的多能干细胞,可以分化为多种体细胞,在损伤组织修复再生和细胞治疗方面显示出巨大的应用前景.改变MSCs的能量代谢模式可以调控其细胞状态与功能,使其在不同条件下更好地发挥功能作用是疾病治疗的关键.MSCs在能量代谢方面有较强的可塑性:在常氧条件下,糖酵解与氧化磷酸化同时存在;而在乏氧条件下则转变为以糖酵解代谢为主.因此,代谢重编程的调控在MSCs的干性维持、分化控制与免疫调节中具有重要的作用.     

小鼠胚胎干细胞向成牙本质样细胞的诱导分化

目的探讨胚胎干细胞(ES细胞)向成牙本质样细胞诱导分化的方法。方法首先通过悬浮培养的方式,将ES细胞诱导分化形成拟胚体,然后将拟胚体细胞与牙髓成纤维细胞通过Transwell培养系统共培养,研究拟胚体细胞向成牙本质样细胞的分化情况。结果RT-PCR结果显示,拟胚体细胞与牙髓成纤维细胞共培养10d后,可检测到成牙本质细胞的特征性分子——牙本质涎磷蛋白(DSPP)的表达;共培养15d后,表达有所增强。而单独培养的拟胚体细胞,则始终未检测到DSPP的表达。结论通过与牙髓成纤维细胞共培养,可以促进胚胎干细胞向成牙本质样细胞分化。     

英文文摘

1.猪牙胚细胞条件培养基可诱导人牙髓干细胞的牙向分化(英)/Wang YX…//J Tissue Eng Regen Med.-2011,5(5).-354～362牙源性干细胞的分化受其所处的局部微环境所调控。以往研究表明牙胚细胞条件培养基可诱导牙髓干细胞向成牙的细胞谱系分化。然而,采用人牙胚细胞条件培养基诱导在实际操作中不可行,所以推测异种的牙胚细胞条件培养基可能对人牙髓干细胞产生类似的效应。本研究采用猪的牙胚细胞条件培养基(pTGC-CM)来诱导人牙髓干细胞,评估其诱导前后的     

诱导性多能干细胞在口腔医学中的应用研究

诱导性多潜能干细胞（induced pluripotent stem cells, iPSC）是将特定的限定因子导入动物体细胞内,使其重编程为具有胚胎干细胞特性的iPSC,这一成果揭开了干细胞研究的新篇章。各国研究者们就如何提高体细胞重编程效率及安全性,进而推动细胞在临床领域的应用展开了广泛研究。 iPSC在口腔医学领域的研究也备受关注,牙髓、牙周及黏膜等口腔组织来源细胞被诱导形成iPSC,而其他组织来源的iPSC也成功诱导向牙齿、牙周特定细胞分化,有望为口腔组织再生提供足量、可靠的细胞来源,展示出广阔的临床应用前景。     

牙髓干细胞与牙本质再生相关性的研究进展

牙髓中存在具备自我更新和多向分化潜能的牙髓干细胞.这些细胞经诱导可向成牙本质细胞分化并形成牙本质样结构,有望成为牙本质再生的种子细胞.本文就牙髓干细胞的来源、生物学特性及其在牙本质再生中的应用作一综述.     

牙髓干细胞与牙本质再生相关性的研究进展

牙髓中存在具备自我更新和多向分化潜能的牙髓干细胞。这些细胞经诱导可向成牙本质细胞分化并形成牙本质样结构，有望成为牙本质再生的种子细胞。本文就牙髓干细胞的来源、生物学特性及其在牙本质再生中的应用作一综述。     

Dental pulp stem cells, niches, and notch signaling in tooth injury

Stem cells guarantee tissue repair and regeneration throughout life. The decision between cell self-renewal and differentiation is influenced by a specialized microenvironment called the 'stem cell niche'. In the tooth, stem cell niches are formed at specific anatomic locations of the dental pulp. The microenvironment of these niches regulates how dental pulp stem cell populations participate in tissue maintenance, repair, and regeneration. Signaling molecules such as Notch proteins are important regulators of stem cell function, with various capacities to induce proliferation or differentiation. Dental injuries often lead to odontoblast apoptosis, which triggers activation of dental pulp stem cells followed by their proliferation, migration, and differentiation into odontoblast-like cells, which elaborate a reparative dentin. Better knowledge of the regulation of dental pulp stem cells within their niches in pathological conditions will aid in the development of novel treatments for dental tissue repair and regeneration.     

Induced migration of dental pulp stem cells for in vivo pulp regeneration

Dental pulp has intrinsic capacity for self-repair. However, it is not clear whether dental pulp cells can be recruited endogenously for regenerating pulp tissues, including mineralizing into dentin. This work is based on a hypothesis that dental pulp stem/progenitor cells can be induced to migrate by chemotactic cytokines and act as endogenous cell sources for regeneration and mineralization. Dental stem cells (DSCs) were isolated from adult human tooth pulp and seeded on the surfaces of 3D collagen gel cylinders that were incubated in chemically defined media with stromal-derived factor-1α (SDF1), basic fibroblast growth factor (bFGF), or bone morphogenetic protein-7 (BMP7). Significantly more cells were recruited into collagen gel by SDF1 or bFGF than without cytokines in 7 days, whereas BMP7 had little effect on cell recruitment. BMP7, however, was highly effective, equally to dexamethasone, in orchestrating mineralization of cultured DSCs. Cell membrane receptors for SDF1, bFGF, and BMP7 were up-regulated in treated DSCs. Upon in vivo delivery, bFGF induced re-cellularization and re-vascularization in endodontically treated human teeth implanted into the dorsum of rats. Thus, endogenous dental pulp cells, including stem/progenitor cells, may be recruited and subsequently differentiated by chemotaxis of selective cytokines in the regeneration of dental pulp.     

牙髓干细胞分化过程中L型钙离子通道羧基末端的表达

目的:探讨牙髓干细胞(DPSCs)分化过程中L型钙离子通道羧基末端的表达。方法:利用酶消化法体外分离、培养大鼠牙髓干细胞;吉姆萨染色法检测大鼠牙髓干细胞的克隆形成能力;神经诱导体系下诱导牙髓干细胞向神经样细胞分化,免疫荧光染色检测细胞分化后胶质纤维酸蛋白(glial fibrillary acidic pro-tein,GFAP)的表达和细胞分化前后L型钙离子通道Cav 1.2及羧基末端的表达。结果:牙髓干细胞的克隆形成能力为每1 000个细胞形成2～17个克隆;免疫荧光染色检测诱导后细胞GFAP表达阳性;免疫荧光染色检测显示:牙髓干细胞分化前L型钙离子通道Cav 1.2羧基末端表达于细胞膜上,细胞分化后羧基末端同时表达于细胞膜上和细胞核中。结论:L型钙离子通道Cav 1.2羧基末端在牙髓干细胞分化过程中发生核转位,羧基末端可能在牙髓干细胞的分化过程中发挥着一定的作用。     

Somatic stem cells for regenerative dentistry

Complex human tissues harbour stem cells and/or precursor cells, which are responsible for tissue development or repair. Recently, dental tissues such as periodontal ligament (PDL), dental papilla or dental follicle have been identified as easily accessible sources of undifferentiated cells. The dental stem cell biology might provide meaningful insights into the development of dental tissues and cellular differentiation processes. Dental stem cells could also be feasible tools for dental tissue engineering. Constructing complex structures like a periodontium, which provides the functional connection between a tooth or an implant and the surrounding jaw, could effectively improve modern dentistry. Dental precursor cells are attractive for novel approaches to treat diseases like periodontitis, dental caries or to improve dental pulp healing and the regeneration of craniofacial bone and teeth. These cells are easily accessible and, in contrast to bone-marrow-derived mesenchymal stem cells, are more closely related to dental tissues. This review gives a short overview of stem cells of dental origin.     

体外培养牙髓细胞分化相关标记物的研究进展

体外培养的牙髓细胞在形态上同一般成纤维细胞相似,但在生物学特性上却表现出较高的分化能力。近年来的研究表明,牙髓细胞中存在未分化的间充质干细胞,属于成体干细胞,在不同的诱导条件下表现出多向分化能力。本文就牙髓细胞分化过程中的相关标记物如碱性磷酸酶活性、矿化结节以及牙本质涎磷蛋白(DSPP)等研究进展作一综述。     

Hypoxia-amplified Proliferation of Human Dental Pulp Cells

IntroductionPostnatal human dental pulp is a potentially promising source of progenitor cells. Sustaining and amplifying progenitor cell populations would be beneficial for basic science research with application in pulpal regeneration. Hypoxia has been observed to promote the undifferentiated cell state in various stem cell populations. The purpose of this study was to examine human dental pulp cells (DPCs) proliferation in normoxia and hypoxia.MethodsDental pulp cells were obtained from third molars of adult patients and cultured in alpha modification of Eagle's medium culture medium with 10% fetal bovine serum. For cell proliferation, DPCs were divided into two groups: (1) DPCs incubated in normoxic conditions (20% oxygen tension) and (2) DPC incubated in hypoxic conditions (3% oxygen tension). Cell proliferation assays were performed every 2 to 3 days from day 3 to day 14 by trypsinization and quantification of cells with a hemacytometer. Fluorescence-activated cell sorting analysis was completed to investigate stem cell markers, CD133, and STRO-1.ResultsDPCs proliferated significantly more in hypoxia than in normoxia (ie, two-fold throughout the experiment, p < 0.0001). The primitive stem cell marker, CD133, decreased in hypoxia, whereas the osteoprogenitor marker, STRO-1, increased by 8.5-fold.ConclusionsThis study suggested that hypoxia is an effective treatment to amplify numbers of progenitor cells from human dental pulp.     

Notch信号通路在牙髓干细胞增殖和分化中的调控作用

Notch信号通路是进化过程中高度保守的信号转导机制,通过细胞与细胞间的相互作用控制细胞的命运。牙髓干细胞是一种具有高度增殖和多向分化潜能的成体干细胞,在组织再生中发挥重要作用。该文就该信号通路的组成及其对牙髓干细胞调控的分子机制作一综述。     

牙髓干细胞分化的研究进展

牙髓干细胞(DPSC)是一种具有高度增生、自我更新能力和多相分化潜能的成体干细胞,在一定条件下可向特定的细胞类型分化,在牙髓修复和牙齿再生中发挥着重要的作用。本文主要就DPSC成骨向分化、成牙本质向分化的研究进展作一综述。     

干细胞和支架与牙髓再生及其血运重建

在牙髓再生中,获取干细胞的方法包括干细胞移植、细胞归巢和诱导出血。干细胞移植可产生异位的牙髓样组织,可控制移植细胞的数量并选择对牙髓再生潜在效能最佳的细胞亚种。细胞归巢是指利用信号分子招募宿主内源性干细胞至需治疗的牙体根管中增殖和分化,形成牙髓-牙本质样组织。诱导根尖出血进入根管为年轻恒牙牙髓再生的一个重要步骤。支架是细胞在合成组织时的支撑结构,可促进细胞黏附,为牙髓再生提供有利的环境。牙髓再生离不开血运重建或者血管再生,感染控制、根管预处理、冠方封闭等操作,可为牙髓再生包括其血运重建提供适宜的环境。总之,组织工程技术在牙髓领域的应用发展为牙髓再生带来了新的希望。     

Oct4调节成体干细胞多能性的研究进展

成体干细胞是存在于人和哺乳动物特定组织中的具有自我更新和一定分化潜能的未成熟细胞,参与成体组织的更新和创伤修复.牙髓干细胞是牙髓损伤修复的潜能所在,如何调控其生物学行为以促进牙髓修复再生是当前的研究热点.Oct4 在干细胞发育的基因调控网络中居核心地位,近年研究显示Oct4 具有维持成体干细胞多能性的功能.本文通过阐述Oct4 的结构和功能,揭示其在成体干细胞中的调节作用,为研究Oct4 对牙髓干细胞的调节作用提供理论基础.