牙髓干细胞诱导iPS细胞的无饲养细胞培养条件研究

目的研究适合牙髓干细胞诱导iPS细胞的无饲养细胞培养条件与方法。方法分离牙髓干细胞,慢病毒介导Lin28、Nanog、Oct4和Sox2因子重编程获得iPS细胞。在不同浓度及不同处理时间的基质胶（Matrigel）上传代培养iPS,检验iPS的单细胞生长密度,比较不同基质胶培养方法对iPS生长的影响。结果 DPSC iPS在60ug/cm^2浓度的基质胶上生长密度最高;基质胶覆盖2小时后应用可以获得最好的DPSC iPS生长密度。。结论应用60ug/cm^2浓度的基质胶覆盖培养板2小时是DPSC iPS无饲养细胞培养的最佳条件。     

人乳牙牙髓干细胞和恒牙牙髓干细胞的蛋白质组学比较

目的 采用蛋白质组学方法研究人乳牙牙髓干细胞（SHED）和恒牙牙髓干细胞（DPSC）中的蛋白表达差异.方法 应用双向凝胶电泳技术分离SHED和DPSC的细胞总蛋白.通过比较两种细胞的蛋白组学图谱,确定差异表达的蛋白点,而后对差异点进行基质辅助激光解析电离飞行时间质谱分析和蛋白数据库信息检索,对差异蛋白进行功能分类.结果 建立了SHED和DPSC的蛋白质组图谱,经软件分析出45个差异蛋白点,其中26个表达上调,19个表达下调,再经质谱鉴定出48种蛋白,其生物学功能涉及细胞周期、代谢等.结论 SHED与DPSC中蛋白的差异表达体现了两种细胞在结构和功能上的异同性,为进一步研究SHED和DPSC在增殖、分化中的差异,以及牙齿相关干细胞在组织工程和再生医学研究中的应用提供参考.     

人乳牙牙髓干细胞在干细胞治疗中的应用

乳牙牙髓干细胞（SHED）是牙源性干细胞的一种,属外胚间充质干细胞。作为一种理想的干细胞来源,SHED在干细胞治疗中有良好的应用前景。本文阐述了SHED的生物学特征及其在干细胞治疗中的优势,探讨了SHED在组织再生和修复中发挥的多向分化潜能、细胞分泌功能和免疫调节功能等方面的功能作用。此外,本文还介绍了SHED在各系统、器官疾病治疗中的临床应用,重点阐述了用SHED进行干细胞移植在牙髓—牙本质再生、颌骨再生、神经系统疾病治疗和免疫系统疾病治疗方面的研究进展。     

多样本人腮腺间充质干细胞诱导iPS细胞的对比研究

目的研究比较不同样本腮腺间充质干细胞(hPMSCs)生成诱导多潜能干细胞(iPSCs)的效果。方法分别分离培养3个患者的h PMSCs,应用游离质粒混合因子(OCT3/4、SOX2、KLF4、c-MYC、LIN28、TP53 shRNA)电转导法重编程诱导获得iPS细胞(h PMSC-iPSCs)。比较在相同条件下3个不同供体来源腮腺细胞诱导iPS细胞的差异。结果 3个不同样本人腮腺间充质干细胞都成功诱导iPSCs,形成率分别为0.11%、0.10%、0.09%,无显著性差异(P>0.05);诱导形成iPS克隆时间有差异(P<0.05);形成iPSCs后维持培养倍增时间无差异(P>0.05)。结论不同患者可分离获得hPMSCs后成功诱导hPMSC-iPSCs,诱导效率无差异,诱导时间有差异。     

体外成牙环境对牙髓干细胞和外胚间充质干细胞分化的影响

目的利用牙胚细胞（TGC）作为诱导成牙环境,将牙髓干细胞（DPSC）、外胚间充质干细胞（EMSC）分别与其共培养,观察DPSC和EMSC的分化能力。方法利用出生后4 d的大鼠TGC作为诱导成牙环境,将培养的DPSC、EMSC使用BrdU标记及鉴定后与其共培养,免疫荧光双标检测标记细胞表面抗原牙本质涎蛋白（DSP）的表达和碱性磷酸酶（ALP）活性的变化,免疫组化染色鉴定及图像分析DPSC、EMSC在成牙环境中的分化能力。结果共培养7 d后,EMSC共培养组DSP阳性细胞的转化率高于DPSC共培养组（P<0.05）。免疫组化染色图像分析结果表明共培养7 d后,共培养组与TGC单独培养组差异显著（P<0.05）。共培养组3、7 d后ALP活性明显增高,EMSC共培养组较DPSC共培养组ALP活性高。结论混合培养的TGC作为诱导细胞分化的微环境与DPSC、EMSC共培养后,能够诱导细胞向成牙本质细胞分化,EMSC分化能力高于DPSC。     

RNA复制子诱导人牙源性多潜能干细胞的研究

目的研究一种高效安全的人诱导性多潜能干细胞(Induced pluripotent stem cells,i PSCs)重编程新体系,为牙源性组织再生提供安全的干细胞来源。方法体外培养人根尖乳头干细胞(Stem cells from apical papilla,SCAP),Simplicon RNA复制子为载体,人重组玻连蛋白作为底物,将人SCAP重编程为i PSCs。免疫荧光染色检测i PSCs特异性标记物的表达,畸胎瘤形成实验检测i PSCs分化能力,RT-PCR确认其外源性基因序列的沉默。计算人SCAP-i PSCs的重编程效率。结果人SCAPi PSCs具备典型的ES样克隆形态,Oct4、Nanog、Sox2、SSEA-4均为染色阳性。i PSCs植入SCID小鼠体内6周形成畸胎瘤,HE染色显示包含所有三胚层来源组织,RT-PCR显示人SCAP-i PSCs特异性表达干细胞标记物,不再表达外源性基因序列。重编程效率为0.17%~0.20%。结论结果得到的人SCAP-i PSCs安全性能和诱导效率较高,是理想的牙源性组织再生的干细胞来源。     

釉质基质蛋白对乳牙牙髓干细胞体外增殖、分化能力的影响

目的：研究釉质基质蛋白（enamel matrix proteins,EMPs）对人脱落乳牙牙髓干细胞（stem cells from hu—man exfoliated dediduous teeth,SHED）体外增殖分化能力的影响。方法：利用酶消化法联合组织块法获得脱落乳牙牙髓干细胞,并进行形态学观察。三氯乙酸法制备EMPs,用不同浓度的EMPs对SHED进行诱导,利用四唑盐比色法（MTT）检测并分析诱导后的SHED增殖活性的变化,检测经诱导后的培养液中碱性磷酸酶（ALP）。RT—PCR检测牙本质涎磷蛋白（dentin sialophosphoprotein,DSPP）及牙本质基质蛋白1（dentin matrix protein1,DMP-1）的mRNA表达。结果：人脱落乳牙牙髓干细胞呈集落生长,并且在体外具有一定的自我增殖能力。EMPs对乳牙牙髓干细胞的增殖无明显影响,而能够显著提高ALP的活性,并呈现一定的剂量依赖性。经EMPs诱导后,细胞相对高表达DSPP、DMP-1mRNA。结论：EMPs对于SHED向成牙本质样分化具有积极作用。     

促丝裂原激活蛋白激酶在牙髓干细胞向成牙本质细胞分化和牙髓损伤修复中的作用

通过诱导牙髓干细胞（DPSC）向成牙本质细胞方向分化,龋源性牙髓炎的治疗将不再局限于根管治疗这一临床选择,修复治疗也不再成为缺失牙治疗的唯一方案。促丝裂原激活蛋白激酶（MAPK）,尤其是P38MAPK通过直接或间接磷酸化特定的转录因子,将细胞外刺激信号转导至细胞及其核内,从而引起一系列细胞生物学反应,如细胞增殖、分化、转化和程序性死亡。骨形态发生蛋白-2、矿物三氧化物聚合体和Biodentine皆可诱导DPSC向成牙本质细胞分化,而三者正是通过MAPK信号转导通路发挥作用的。在组织工程支架诱导DPSC分化过程中,支架材料通过激活P38MAPK信号转导通路促进了DPSC的分化。此外,MAPK信号转导通路参与牙髓损伤修复中DPSC的迁移、黏附和分化,参与牙髓损伤修复中牙本质的形成。由于MAPK信号转导通路在细胞增殖、分化和生存等过程中都起着十分关键的作用,因此,深入研究其反应分子、作用底物和作用机制有着重要的理论和临床意义。     

人牙源性多能干细胞重编程前后微小RNAs差异表达谱系分析

目的 对比研究两种人牙源性多能干细胞重编程前后微小RNAs（miRNAs）差异表达,交集分析、筛选特异性miRNAs。方法 利用仙台病毒将人牙髓干细胞（DPSCs）和根尖乳头干细胞（SCAP）重编程为诱导性多潜能干细胞（iPSCs）,提取总RNA,miRNAs标记、杂交,扫描芯片、读取图像,筛选差异表达miRNAs,交集分析。结果 人DPSCs和SCAP均可重编程为iPSCs。miRNAs芯片分析结果显示人DPSCs重编程后有68个差异表达miRNAs（倍数>10）,其中37个表达上调,31个表达下调;人SCAP重编程后有107个差异表达miRNAs（倍数>10）,其中68个表达上调,39个表达下调。二者取交集,均上调的有miR-302e,下调的有miR-29b-3p、miR-181b-5p、miR-4328、miR-22-5p、miR-145-5p、miR-4324、let-7b-5p、miR-181a-5p、miR-27b-3p（倍数>10）。结论 人DPSCs和SCAP重编程为iPSCs过程中有多种miRNAs参与,多数与细胞周期、上皮-间充质转化、转化生长因子β信号通路等相关。     

人乳牙牙髓干细胞体外表达和分泌胶质细胞源性神经营养因子的研究

目的 研究人乳牙牙髓干细胞(SHED)表达和分泌胶质细胞源性神经营养因子(GDNF)的能力及规律,为进一步探讨SHED治疗帕金森病的作用机制提供依据.方法 通过酶消化法体外分离培养人乳牙牙髓中的干细胞,当传代至第3代时,加入神经干细胞的特殊培养基Neurobasal A和细胞因子进行神经球诱导培养,通过Real-Ti...     

人乳牙牙髓干细胞和成人牙髓干细胞研究进展

近年来,成体干细胞不断地从不同的组织中被分离出来,该类细胞具有多向分化潜能、较强的增殖能力和持久的自我更新能力,具备充当组织工程种子细胞的天然优势。2000年和2003年,研究者先后从成人牙髓组织和人乳牙牙髓组织中分离出具有干细胞特征的细胞,这两种细胞的发现对牙组织工程将产生重要的意义。现就这两种成体干细胞的研究进展做一综述,并展望其应用前景。     

牙源性干细胞及牙髓再生的研究进展

牙髓组织中含有细胞、血管、神经和纤维等,是一个复杂的3D结构系统。随着干细胞生物学和组织工程学的相互结合和促进,牙髓再生逐渐成为可能。牙体组织中分离出的多种干细胞,如牙髓干细胞、脱落乳牙牙髓干细胞、根尖牙乳头干细胞、牙囊干细胞等,都具有再生牙髓的潜能。文章就牙源性干细胞及以牙源性干细胞为基础的牙髓再生的研究进展做一综述。     

Differentiation of stem cells from human deciduous and permanent teeth into spiral ganglion neuron-like cells

ObjectiveStem cells from pulp tissue are a promising cell-based therapy for neurodegenerative patients based on their origin in the neural crest. The aim of this study was to differentiate and evaluate the ability of human dental pulp stem cells from permanent teeth (DPSC) and stem cells from human exfoliated deciduous teeth (SHED) to differentiate into spiral ganglion neurons.DesignAfter isolation and characterization of mesenchymal stem cell properties, DPSC and SHED were treated with the neurotrophins brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3), and glial cell-derived neurotrophic factor (GDNF). The differentiation was identified by immunostaining and qRT-PCR analysis of neuronal markers and measuring intracellular calcium activity.ResultsAfter 2 weeks of induction, morphological changes were observed in both DPSC and SHED. The differentiated cells expressed neuron-specific class III beta-tubulin, GATA binding protein 3 (GATA3) and tropomyosin receptor kinase B, protein markers of spiral ganglion neurons. These cells also showed upregulation of the genes encoding these proteins, namely GATA3 and neurotrophic receptor tyrosine kinase 2. Intracellular calcium dynamics that reflect neurotransmitter release were observed in differentiated DPSC and SHED.ConclusionThese results demonstrate that dental pulp stem cells from permanent and deciduous teeth can differentiate into spiral ganglion neuron-like cells.     

The efficacy of mesenchymal stem cells to regenerate and repair dental structures

OBJECTIVES: Identification, characterization, and potential application of mesenchymal stem cells (MSC) derived from human dental tissues. METHODS: Dental pulp and periodontal ligament were obtained from normal human impacted third molars. The tissues were digested in collagenase/dispase to generate single cell suspensions. Cells were cultured in alpha-MEM supplemented with 20% fetal bovine serum, 2 mM l-glutamine, 100 microM l-ascorbate-2-phosphate. Magnetic and fluorescence activated cell sorting were employed to characterize the phenotype of freshly isolated and ex vivo expanded cell populations. The developmental potential of cultured cells was assessed following co-transplantation with hydroxyapetite/tricalcium phosphate (HA/TCP) particles into immunocompromised mice for 8 weeks. RESULTS: MSC were identified in adult human dental pulp (dental pulp stem cells, DPSC), human primary teeth (stem cells from human exfoliated deciduous teeth, SHED), and periodontal ligament (periodontal ligament stem cells, PDLSC) by their capacity to generate clongenic cell clusters in culture. Ex vivo expanded DPSC, SHED, and PDLSC populations expressed a heterogeneous assortment of makers associated with MSC, dentin, bone, smooth muscle, neural tissue, and endothelium. PDLSC were also found to express the tendon specific marker, Scleraxis. Xenogeneic transplants containing HA/TCP with either DPSC or SHED generated donor-derived dentin-pulp-like tissues with distinct odontoblast layers lining the mineralized dentin-matrix. In parallel studies, PDLSC generated cementum-like structures associated with PDL-like connective tissue when transplanted with HA/TCP into immunocompromised mice. CONCLUSION: Collectively, these data revealed the presence of distinct MSC populations associated with dental structures with the potential of stem cells to regenerate living human dental tissues in vivo.     

Stem cell properties of human dental pulp stem cells

In this study, we characterized the self-renewal capability, multi-lineage differentiation capacity, and clonogenic efficiency of human dental pulp stem cells (DPSCs). DPSCs were capable of forming ectopic dentin and associated pulp tissue in vivo. Stromal-like cells were reestablished in culture from primary DPSC transplants and re-transplanted into immunocompromised mice to generate a dentin-pulp-like tissue, demonstrating their self-renewal capability. DPSCs were also found to be capable of differentiating into adipocytes and neural-like cells. The odontogenic potential of 12 individual single-colony-derived DPSC strains was determined. Two-thirds of the single-colony-derived DPSC strains generated abundant ectopic dentin in vivo, while only a limited amount of dentin was detected in the remaining one-third. These results indicate that single-colony-derived DPSC strains differ from each other with respect to their rate of odontogenesis. Taken together, these results demonstrate that DPSCs possess stem-cell-like qualities, including self-renewal capability and multi-lineage differentiation.     

Comparative characterization of stem cells from human exfoliated deciduous teeth and dental pulp stem cells

ObjectiveThis study focused on the characterization of stem cells from human exfoliated deciduous teeth (SHED) in comparison with dental pulp stem cells (DPSCs) to certify SHED as a key element in tissue engineering.MethodsIn the present study, SHED and DPSCs were assayed for their cell surface antigens and proliferation by measuring the cell cycles, growth rates, Ki67-positive efficiencies, and colony-forming units (CFUs). The evaluation of multi-differentiation was performed using alizarin red and oil red O and real-time PCR in vitro. The mineralization capability of the cells was examined in vivo by implanting with ceramic bovine bone (CBB) into subcutaneous of immunocompromised mice for 8 weeks. A three-dimensional pellet cultivation system is proposed for SHED and DPSCs to recreate the biological microenvironment that is similar to that of a regenerative milieu.ResultsSHED showed a higher proliferation rate and differentiation capability in comparison with DPSCs in vitro, and the results of the in vivo transplantation suggest that SHED have a higher capability of mineralization than the DPSCs. The mRNA expression levels of inflammatory cytokines, including matrix metalloproteinase-1 (MMP1), tissue inhibitors of metalloproteinase-1 (TIMP1), matrix metalloproteinase-2 (MMP2), tissue inhibitors of metalloproteinase-2 (TIMP2) and interleukin-6 (IL-6) were higher in SHED than that in DPSCs. In addition, the expression levels of Col I and proliferating cell nuclear antigen (PCNA) in SHED sheets were significantly higher than those in DPSCs sheets.ConclusionsThis study systematically demonstrated the differences in the growth and differentiation characteristics between SHED and DPSCs. Consequently, SHED may represent a suitable, accessible and potential alternative source for regenerative medicine and therapeutic applications.     

Characterization of the apical papilla and its residing stem cells from human immature permanent teeth: a pilot study

Mesenchymal stem cells (MSCs) have been isolated from the pulp tissue of permanent teeth (dental pulp stem cells or DPSCs) and deciduous teeth (stem cells from human exfoliated deciduous teeth). We recently discovered another type of MSCs in the apical papilla of human immature permanent teeth termed stem cells from the apical papilla (SCAP). Here, we further characterized the apical papilla tissue and stem cell properties of SCAP using histologic, immunohistochemical, and immunocytofluorescent analyses. We found that the apical papilla is distinctive to the pulp in terms of containing less cellular and vascular components than those in the pulp. Cells in the apical papilla proliferated 2- to 3-fold greater than those in the pulp in organ cultures. Both SCAP and DPSCs were as potent in osteo/dentinogenic differentiation as MSCs from bone marrows, whereas they were weaker in adipogenic potential. The immunophenotype of SCAP is similar to that of DPSCs on the osteo/dentinogenic and growth factor receptor gene profiles. Double-staining experiments showed that STRO-1 coexpressed with dentinogenic markers such as bone sialophosphoprotein, osteocalcin, and growth factors FGFR1 and TGFbetaRI in cultured SCAP. Additionally, SCAP express a wide variety of neurogenic markers such as nestin and neurofilament M upon stimulation with a neurogenic medium. We conclude that SCAP are similar to DPSCs but a distinct source of potent dental stem/progenitor cells. Their implications in root development and apexogenesis are discussed.