尼古丁抑制人牙髓干细胞增殖和分化

目的探讨尼古丁的刺激对人牙髓干细胞增殖、分化的影响。方法培养人牙髓干细胞,流式细胞计量术鉴定细胞表面抗原;用不同浓度的尼古丁(10-4、10-3和10-2 mol/L)刺激牙髓干细胞,培养0、1、2、3和4 d后,CCK8法检测细胞增殖能力;茜素红染色法检测细胞分化过程中矿化结节形成,RT-qPCR和免疫印迹(Western blot)检测牙本质涎磷蛋白(DSPP)、碱性磷酸酶(ALP)、骨桥素(OPN)及细胞外信号调节激酶(ERK)、c-Jun氨基末端激酶(JNK)、p38(p-ERK、p-JNK、p-p38)等MAPK通路相关蛋白表达。结果培养第3、4天时,与对照组相比,尼古丁刺激时A值显著降低(P<0.05);与对照组相比,尼古丁刺激时矿化结节形成数、DSPP、ALP、OPN mRNA和蛋白、p-ERK、p-JNK、p-p38蛋白表达显著降低(P<0.05)。结论尼古丁抑制人牙髓干细胞增殖、成骨分化能力。     

牙髓干细胞培养及分化的研究进展

干细胞是未分化的细胞,具有自我更新、高度增殖及多向分化等特性。牙髓干细胞(dental pulp stem cell,DPSC)不仅具有干细胞的上述特性,而且具有取材方便、易于培养、易于冷藏等优点。本文就DPSC与其他三种干细胞在培养多向分化潜能、分化诱导因素、向诱导性多功能干细胞(induced pluripotent stem cell,i PSC)的分化潜能以及在组织工程学中的应用进行比较,并讨论DPSC的培养及分化优势。     

FGF8辅助牙源性上皮诱导hDPSCs分化为成牙本质细胞及牙髓细胞

目的:研究成纤维细胞生长因子8(FGF8)对成人牙髓干细胞(hDPSCs)定向分化为成牙本质细胞及牙髓组织的影响。方法:首先分离、克隆培养hDPSCs,通过流式细胞术检测细胞表面标志物鉴定hDPSCs;矿化液中添加50μg/L的FGF8诱导hDPSCs分化,通过real-time PCR检测分化后的细胞中牙本质涎磷蛋白(DSPP)、碱性磷酸酶(ALP)、骨涎蛋白(BSP)和核心结合因子α1(Cbfa-1)在mRNA水平的表达;E11.5小鼠牙源性上皮联合FGF8与hDPSCs细胞团重组,再将组织块种植于裸鼠肾囊膜下培养,通过DNA原位杂交鉴定成牙本质细胞及牙髓细胞的来源。结果:成功分离培养hDPSCs,其表面标志物CD29和CD90呈阳性表达;经FGF8诱导的hDPSCs形成较明显的矿化结节,并且牙本质特异性蛋白DSPP、BSP及Cbfa-1表达量上调;E11.5小鼠牙源性上皮联合FGF8可以诱导hDPSCs分化为成牙本质细胞及牙髓细胞。结论:FGF8能够辅助牙源性上皮定向诱导hDPSCs分化为成牙本质细胞及牙髓细胞,并形成牙本质及牙髓腔结构。     

Effect of cyclic uniaxial compressive stress on human dental pulp cells in vitro

Purpose: Teeth are exposed to various forces during functional and parafunctional movements. These processes inevitably affect the dental pulp, and the mechanism of these influences has been the subject of many previous studies using different apparatuses and obtaining different results. In this study, we aimed to investigate the effects of compressive stress on the proliferation and differentiation of human dental pulp cells (hDPCs).

Materials and Methods: A four-point bending strain system was adopted to apply low-density cyclic uniaxial compressive stress (2000 microstrain, 0.5 Hz) to hDPCs for 1.5, 3, 6, 12, and 24 h. The cell cycle progression and mRNA expression of differentiation-related genes (BMP2, ALP, DMP1, DSPP, COL I) were then examined to investigate the proliferation and differentiation of hDPCs.

Results: The results showed that cyclic compressive stress changed the morphology of hDPCs after 12 and 24 h of mechanical loading; cell cycle progression was promoted, especially in the 24-h group (p < 0.05). The expression of BMP2 was significantly upregulated after 3 and 6 h of mechanical loading but declined in the 12- and 24-h groups, whereas the expression levels of DMP1 and DSPP were significantly upregulated in the 12- and 24-h loading groups (p < 0.05).

Conclusions: Dental pulp cells were sensitive to compressive stress, especially after 12 and 24 h of applied force. Proliferation and odontogenic differentiation were significantly promoted in this in vitro model.     

1,25-Dihydroxyvitamin D3 stimulates odontoblastic differentiation of human dental pulp-stem cells in vitro

Background: 1,25-Dihydroxyvitamin D₃ (1,25-OH D₃) plays an important role in mineralized tissue metabolism, including teeth. However, few studies have addressed its role in odontoblastic differentiation of human dental pulp-stem cells (hDPSCs). Aim: This study aimed to understand the influence of various concentrations of 1,25-OH D₃ on the proliferation capacity and early dentinogenesis responses of hDPSCs. Materials and Methods: hDPSCs were obtained from the impacted third molar teeth. Monolayer cultured cells were incubated with a differentiation medium containing different concentrations of 1,25-OH D₃ (0.001, 0.01, and 0.1 µM). All groups were evaluated by S-phase rate [immunohistochemical (IHC) bromodeoxyuridine (BrdU) staining], STRO-1 and dentin sialoprotein (DSP)+ levels (IHC), and alkaline phosphatase (ALP, enzyme-linked immunosorbent assay (ELISA)) levels. Results: The number of cells that entered the S-phase was determined to be the highest and lowest in the control and 0.001 µM 1,25-OH D₃ groups, respectively. The 0.1 µM vitamin D₃ group had the highest increase in DSP+ levels. The highest Stro-1 levels were detected in the control and 0.1 µM 1,25-OH D₃ groups, respectively. The 0.1 µM 1,25-OH D₃ induced a mild increase in ALP activity. Conclusions: This study demonstrated that 1,25-OH D₃ stimulated odontoblastic differentiation of hDPSCs in vitro in a dose-dependent manner. The high DSP + cell number and a mild increase in ALP activity suggest that DPSCs treated with 0.1 μM 1,25-OH D₃ are in the later stage of odontoblastic differentiation. The results confirm that 1,25-OH D₃-added cocktail medium provides a sufficient microenvironment for the odontoblastic differentiation of hDPSCs in vitro.     

牙乳头细胞对大鼠牙髓干细胞中Notch信号的影响

目的探讨大鼠牙乳头细胞对牙髓干细胞增殖作用的影响过程中,相关牙齿发育信号通路的机制。方法原代培养大鼠牙髓干细胞和牙乳头细胞,建立牙髓干细胞和牙乳头细胞的分层共培养体系。共培养5d后,应用反转录聚合酶链反应(RT-PCR)和Western blot方法检测Notch信号通路中Notch2、Hes1 mRNA与蛋白的表达。结果 RT-PCR和Western blot结果显示牙髓干细胞和牙乳头细胞分层共培养组中Notch2、Hes1 mRNA和蛋白表达水平较单纯牙髓干细胞培养组显著增强(P<0.01)。结论牙乳头细胞促进大鼠牙髓干细胞增殖可能与牙乳头细胞促进牙髓干细胞中Notch信号分子的表达有关。     

Differential effects of growth differentiation factor-5 on porcine dental papilla- and follicle-derived cells

In this study, the effect of growth differentiation factor-5 (GDF-5) on the growth and differentiation of porcine dental papilla- and follicle-derived cells was investigated. Furthermore, the effect was compared with that of BMP-2. Recombinant mouse GDF-5 (rmGDF-5) enhanced alkaline phosphatase (ALP) activity in dental papilla-derived cells in a dose-dependent manner, while ALP activity in dental follicle-derived cells was reduced. In rmGDF-5 stimulated dental papilla-derived cells, the expressions of odontoblast-marker genes were up-regulated. Conversely, recombinant human BMP-2 (rhBMP-2) enhanced ALP activity dose-dependently in both dental papilla- and follicle-derived cells. When combined, GDF-5 did not further enhance BMP-2-induced ALP activities. Rather, GDF-5 reduced BMP-2-induced ALP activities in both dental papilla- and follicle-derived cells. This suggests that affinity of GDF-5 to the shared receptors may be higher than that of BMP-2 in both cell types. These observations indicate that GDF-5 regulates differentiation of both dental papilla and follicle during odontogenesis, co-operatively with other growth factors such as BMP-2.     

脂多糖改变牙髓干细胞的生物学特性

背景:龋病发生时,包括细菌在内的各种刺激沿牙本质小管传导至牙髓,牙髓组织中的牙髓干细胞受到刺激后增殖迁移至受损的牙本质下方,形成修复性牙本质以补充和修复受损组织。在此过程中,脂多糖作为细菌的主要毒力因子,是否可以影响牙髓干细胞增殖、迁移及成牙本质向分化等生物学行为,还有待研究。目的:观察脂多糖对牙髓干细胞增殖能力、迁移能力和成牙本质向分化能力的影响。方法:组织块酶消化法培养牙髓干细胞,给予0,0.1,1,10 mg/L脂多糖刺激后,采用MTT法检测牙髓干细胞增殖情况,划痕实验和Transwell实验检测牙髓干细胞的迁移能力;给予1 mg/L脂多糖和矿化诱导液刺激21 d后,茜素红染色检测细胞矿化结节形成能力,RT-PCR检测成牙本质相关基因的表达。结果与结论:①0.1,1,10 mg/L脂多糖组的吸光度值在第1,3,5,7天4个时间点均低于0 mg/L脂多糖组(P<0.01),迁移能力均高于0 mg/L脂多糖组;②牙髓干细胞矿化诱导21 d后,1 mg/L脂多糖刺激组所形成的矿化结节数量和面积明显小于0 mg/L脂多糖组(P<0.01),成牙本质相关基因OCN、BSP、ALP表达量显著低于0 mg/L脂多糖组(P<0.01);③结果表明,脂多糖刺激牙髓干细胞后其增殖能力和成牙本质向分化能力降低,迁移能力明显增强。     

激活素A和骨形成蛋白-4诱导人羊膜上皮细胞转分化为心肌样细胞的实验研究

近年来羊膜上皮细胞(AECs)被认为是心肌细胞移植较好的种子细胞之一。研究表明,激活素A(ActivinA)和骨形成蛋白-4(BMP-4)能够诱导人胚胎干细胞向心肌细胞分化。本研究通过体外分离、培养并鉴定人AEC后,采用Activin A和BMP-4作为诱导剂,观察它们能否诱导AEC向心肌样细胞转分化。应用定量RT-PCR、Western blot、免疫细胞化学等方法来检测基因及蛋白表达变化。结果显示,人AEC能够表达上皮细胞特异性蛋白角蛋白19(CK19)。经Activin A和BMP-4共同诱导培养14d后,AEC心肌特异性转录因子Nkx2.5和特异性结构蛋白α-actinin的mRNA表达水平明显升高,同时α-actinin的蛋白表达水平亦明显增加。本实验提示,ActivinA和BMP-4在体外能够诱导人AEC向心肌样细胞转分化,同时该诱导方法可能成为诱导AEC向心肌样细胞转分化的一个新方法。     

CKIP-1 suppresses odontoblastic differentiation of dental pulp stem cells via BMP2 pathway and can interact with NRP1

Aim: Casein kinase 2 interacting protein-1 (CKIP-1) is a recently discovered intracellular regulator of bone formation, muscle cell differentiation, and tumor cell proliferation. Our study aims to identify the inhibition of BMP2-Smad1/5 signaling by CKIP-1 in odontoblastic differentiation of human dental pulp stem cells (DPSCs). Materials and Methods: DPSCs infected CKIP-1 siRNA or transfected CKIP-1 full-length plasmid were cultured in odontoblastic differentiation medium or added noggin (200 ng/mL) for 21 days. We examined the effects of CKIP-1 on odontoblastic differentiation, mineralized nodules formation, and interaction by western blot, real-time polymerase chain reaction (RT-PCR), alkaline phosphatase (ALP) staining, alizarin red S staining, and immunoprecipitation. Results: Firstly, we have demonstrated that CKIP-1 expression markedly decreased time-dependently along with cell odontoblastic differentiation. Indeed, the silence of CKIP-1 upregulated odontoblastic differentiation via BMP2-Smad1/5 signaling, while CKIP-1 over-expression had a negative effect on odontoblastic differentiation of DPSCs. Furthermore, CKIP-1 could interact with Neuropilin-1 (NRP1). Conclusions: This work provides data that advocates a novel perception on odontoblastic differentiation of DPSCs. Therefore, inhibiting the expression of CKIP-1 may be of great significance to the development of dental caries.     

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     

Effect of BMP-9 and its derived peptide on the differentiation of human white preadipocytes

Several studies have shown that bone morphogenetic proteins (BMPs) can influence adipogenic and osteogenic cell lineages. We have shown that a peptide derived from BMP-9 (pBMP-9) at 400 ng/ml inhibits the proliferation of preosteoblasts and induces differentiation. We have now determined the effects of pBMP-9 (400 ng/ml) and equimolar concentrations of BMP-2 (100 ng/ml), BMP-9 (84.6 ng/ml) and pBMP-9 (9.04 ng/ml) on human white preadipocytes (HWP). pBMP-9 dose dependently reduced the proliferation of HWP without affecting the number of apoptotic cells. Incubation of the cells for 1 h with BMP-2, BMP-9 or pBMP-9 activated the Smad1/5/8 pathway, while incubation for 7 days in adipocyte differentiation (AD) serum-free medium containing ciglitazone and equimolar concentrations of BMP-2, BMP-9 or pBMP-9 enhanced the levels of mRNA of the adipogenic markers aP2 and adipoQ and increased the number of lipid vesicles. Thus, pBMP-9, like BMP-9, can increase the AD of HWP in AD serum-free medium.     

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.     

人骨形态发生蛋白-2完整成熟肽基因的克隆

目的：克隆人骨形态发生蛋白－２（ｈＢＭＰ－２）完整肽基因。方法：依据Ｇｅｎｂａｎｋ中ｈＢＭＰ－２的序 化学合成两条引物,从人胎儿骨组织中提取得到的总ＲＮＡ中,通过反转录聚合酶链式反应（ＲＴ－ＰＣＲ）得到ｈＢＭＰ－２完整成熟肽基因。将所得的基因片段插入克隆载体ｐＵＣ－１９并转化大肠杆菌ＪＭ１０９,提取重组质粒,酶切并测序。结果：ＤＮＡ琼脂糖凝胶电泳显示：ＰＣＲ产物为一长约４００ｂｐ的带,阳性克隆质粒     

P38 MAPK信号通路参与BMP-13诱导C3H10T1/2细胞向心肌样细胞分化

 目的 探讨P38MAPK对BMP-13诱导C3H10T1/2细胞向心肌样细胞分化的影响。方法 实验4个部分分组如下：1.BMP-13腺病毒（Ad-BMP-13）对P38MAPK的作用：Ad-BMP-13转染组、Ad-GFP转染组和C3H10空白组。Western blot检测磷酸化P38MAPK（p-P38MAPK）和总P38MAPK（t-P38MAPK）的表达变化,免疫荧光技术定位p-P38MAPK;2.P38MAPK干扰腺病毒（Ad-si-P38）对P38MAPK的作用：si-P38干扰组、si-NC干扰对照组和C3H10空白组。Western blot检测t-P38MAPK的表达;3.Ad-si-P38阻断P38MAPK后对BMP-13诱导分化的影响：si-P38+Ad-BMP-13转染组、si-NC+Ad-BMP-13转染组、si-NC+Ad-GFP转染组和C3H10空白组。Western blot检测cTnT和Cx43的表达,荧光定量PCR检测GATA-4和MEF-2C的mRNA表达;4.SB203580阻断P38MAPK后对BMP-13诱导分化的影响： DMSO+Ad-BMP-13转染组、SB203580(2、5和10μmol/L)+Ad-BMP-13转染组 。荧光定量PCR检测GATA-4和MEF-2C的mRNA表达。结果 BMP-13促进P38MAPK的磷酸化。Ad-si-P38可以有效降低P38MAPK表达水平。Ad-si-P38阻断P38MAPK后BMP-13诱导组cTnT、Cx43表达有明显降低（P<0.05）,GATA-4和MEF-2C的表达也有显著降低（P<0.05）。随P38MAPK特异性抑制剂SB203580浓度增加,BMP-13诱导组GATA-4和MEF-2C的表达降低（P<0.05）。结论 Ad-BMP-13可以通过激活P38MAPK信号通路来调控C3H10T1/2细胞向心肌样细胞分化。     

A method for isolation of viable cells from human dental pulp

Summary A simple, reliable technique for establishing cultures of human pulpal fibroblasts is presented. The technique relies on a sequential digestion of minced pulpal tissue with collagenase and trypsin and produces confluent cultures in 7 to 10 d from four to five pulps.     

Heterodimeric BMP-2/7 exhibits different osteoinductive effects in human and murine cells

As robust osteoinductive cytokines, bone morphogenetic proteins (BMPs) play a significant role in bone tissue engineering. Constituted of two different polypeptides, heterodimeric BMPs are more effective than the homodimers in bone formation. While most studies focused on the murine cell lines, such as murine preosteoblasts MC3T3-E1, the role of heterodimeric BMPs in the osteogenic differentiation of human cells remains uncertain, which hinders their application to practical treatment. In this study, we compared the osteoinductive effects of BMP-2/7 heterodimer in human adipose-derived stem cells (hASCs) with their homodimers BMP-2 and BMP-7, in which MC3T3-E1 cells were utilized as a positive control. The results indicated that BMP-2/7 was not a stronger inducer during the osteogenic differentiation of hASCs as that for MC3T3-E1, and extracellular-signal-regulated kinase signaling played a role in the different effects of BMP-2/7 between hASCs and MC3T3-E1. Our study demonstrates the osteoinductive effects of heterodimeric BMP-2/7 present in a cell-specific pattern and cautions should be taken when applying heterodimeric BMP-2/7 to clinical practice.