Enhanced adipogenic differentiation and reduced collagen synthesis induced by human periodontal ligament stem cells might underlie the negative effect of recombinant human bone morphogenetic protein-2 on periodontal regeneration

Song D‐S, Park J‐C, Jung I‐H, Choi S‐H, Cho K‐S, Kim C‐K, Kim C‐S. Enhanced adipogenic differentiation and reduced collagen synthesis induced by human periodontal ligament stem cells might underlie the negative effect of recombinant human bone morphogenetic protein‐2 on periodontal regeneration. J Periodont Res 2011; 46: 193–203. © 2010 John Wiley & Sons A/S Background and Objective: Recombinant human bone morphogenetic protein‐2 (rhBMP‐2) is a potent inducer for the regeneration of mineralized tissue, but has a limited effect on the regeneration of cementum and periodontal ligament (PDL). The aim of the present study was to determine the effects of rhBMP‐2 on the in vitro and in vivo biologic activity of well‐characterized human PDL stem cells (hPDLSCs) and to elucidate the underlying mechanism of minimal periodontal regeneration by rhBMP‐2. Material and Methods: hPDLSCs were isolated and cultured, and then transplanted into an ectopic subcutaneous mouse model using a carrier treated either with or without rhBMP‐2. Comprehensive histologic, histometric and immunohistochemical analyses were performed after an 8‐wk healing period. The effects of rhBMP‐2 on the adipogenic and osteogenic/cementogenic differentiation of hPDLSCs were also evaluated. The effect of rhBMP‐2 on both soluble and insoluble collagen synthesis was analyzed, and the expression of mRNA and protein for collagen types I, II, III and V was assessed. Results: In the present study, rhBMP‐2 promoted both adipogenic and osteogenic/cementogenic differentiation of hPDLSCs in vitro, and the in vivo potential of hPDLSCs to form mineralized cementum and organized PDL tissue was down‐regulated following treatment with rhBMP‐2. Collagen synthesis, which plays a crucial role in the regeneration of cementum and the periodontal attachment, was significantly reduced, with associated modification of the relevant mRNA and protein expression profiles. Conclusion: In summary, the findings of the present study suggest that enhanced adipogenic differentiation and inhibition of collagen synthesis by hPDLSCs appear to be partly responsible for the minimal effect of rhBMP‐2 on cementum and PDL tissue regeneration by hPDLSCs.     

Dose- and time-dependent effects of recombinant human bone morphogenetic protein-2 on the osteogenic and adipogenic potentials of alveolar bone-derived stromal cells

Park J‐C, Kim J.C, Kim B‐K, Cho K‐S, Im G‐I, Kim B‐S, Kim C‐S. Dose‐ and time‐dependent effects of recombinant human bone morphogenetic protein‐2 on the osteogenic and adipogenic potentials of alveolar bone‐derived stromal cells. J Periodont Res 2012; 47: 645–654. © 2012 John Wiley & Sons A/S Background and Objective: Recombinant human bone morphogenetic protein‐2 (rhBMP‐2) is a well‐known growth factor that can induce robust bone formation, and recent studies have shown that rhBMP‐2‐induced osteogenesis is closely related to adipogenesis. The aim of the present study was to determine the dose‐ and time‐dependent effects of rhBMP‐2 on the osteogenic and adipogenic differentiation of human alveolar bone‐derived stromal cells (hABCs) in vivo and in vitro. Material and Methods: hABCs were isolated and cultured, and then transplanted using a carrier treated either with or without rhBMP‐2 (100 μg/mL) into an ectopic subcutaneous mouse model. Comprehensive histologic and histometric analyses were performed after an 8‐wk healing period. To further understand the dose‐dependent (0, 10, 50, 200, 500 and 1000 ng/mL) and time‐dependent (0, 3, 5, 7 and 14 d) effects of rhBMP‐2 on osteogenic and adipogenic differentiation, in vitro osteogenic and adipogenic differentiation of hABCs were evaluated, and the expression of related mRNAs, including those for alkaline phosphatase, osteocalcin, bone sialoprotein, peroxisome‐proliferator‐activated receptor gamma‐2 and lipoprotein lipase, were assessed using quantitative RT‐PCR. Results: rhBMP‐2 significantly promoted the osteogenic and adipogenic differentiation of hABCs in vivo, and gradually increased both the osteogenic and adipogenic potential in a dose‐ and time‐dependent manner with minimal deviation in vitro. The expression of osteogenesis‐ and adipogenesis‐associated mRNAs were concomitantly up‐regulated by rhBMP‐2. Conclusion: The findings of the present study showed that rhBMP‐2 significantly enhanced the adipogenic as well as the osteogenic potential of hABCs in dose‐ and time‐dependent manner. The control of adipogenic differentiation of hABCs should be considered when regenerating the alveolar bone using rhBMP‐2.     

乏氧微环境下机械应力对人牙周膜干细胞成骨分化的影响

人牙周膜干细胞是牙周组织中具有自我更新和多向分化潜能的一类成体干细胞,在特定诱导条件下可以成骨分化。牙周膜处于一个相对乏氧的环境,人牙周膜干细胞在牙周膜中承载着多种机械应力。探讨乏氧环境下机械应力对人牙周膜干细胞成骨分化的影响更接近于体内环境,更有助于获得真实的牙周组织改建的实验室资料。该文对乏氧微环境下机械应力对人牙周膜干细胞成骨分化的影响做一系统性回顾。     

基质细胞衍生因子-1对炎症和正常来源的 人牙周膜干细胞成骨分化能力的影响

目的 通过体外培养炎症来源的人牙周膜干细胞（iPDLSCs）和正常来源的人牙周膜干细胞（hPDLSCs）,比较基质细胞衍生因子-1（SDF-1）对于两种来源细胞的成骨分化作用。方法 采用组织块酶消化法原代培养iPDLSCs 和hPDLSCs,经有限稀释法纯化,通过流式细胞仪对干细胞表面标记物检测鉴定后,对其进行成骨诱导;MTT法检测并比较SDF-1对两种来源的细胞增殖能力的影响;茜素红染色检测SDF-1作用于两种来源的细胞后钙化骨量的表达;碱性磷酸酶法比较SDF-1作用于两者的成骨分化能力;逆转录聚合酶链反应（RT-PCR）法检测SDF-1作用于两种牙周膜干细胞前后成骨相关基因表达水平的变化。结果 两种来源的牙周膜细胞经纯化后均阳性表达干细胞标记物。hPDLSCs较iPDLSCs增殖能力高;两种细胞经SDF-1成骨诱导培养后,成骨相关基因的表达水平均较诱导前明显上调（P<0.05）,SDF-1在50、200 ng·mL ^-1时分别对iPDLSCs和hPDLSCs细胞成骨分化作用最明显（P<0.05）。结论 正常来源和炎症来源的人牙周膜干细胞均具有成骨分化能力,SDF-1可增强两种来源的牙周膜干细胞的成骨分化能力。     

基质细胞衍生因子-1对炎症和正常来源的人牙周膜干细胞成骨分化能力的影响

目的 通过体外培养炎症来源的人牙周膜干细胞（iPDLSCs）和正常来源的人牙周膜干细胞（hPDLSCs）,比较基质细胞衍生因子-1（SDF-1）对于两种来源细胞的成骨分化作用。方法 采用组织块酶消化法原代培养iPDLSCs 和hPDLSCs,经有限稀释法纯化,通过流式细胞仪对干细胞表面标记物检测鉴定后,对其进行成骨诱导;MTT法检测并比较SDF-1对两种来源的细胞增殖能力的影响;茜素红染色检测SDF-1作用于两种来源的细胞后钙化骨量的表达;碱性磷酸酶法比较SDF-1作用于两者的成骨分化能力;逆转录聚合酶链反应（RT-PCR）法检测SDF-1作用于两种牙周膜干细胞前后成骨相关基因表达水平的变化。结果 两种来源的牙周膜细胞经纯化后均阳性表达干细胞标记物。hPDLSCs较iPDLSCs增殖能力高;两种细胞经SDF-1成骨诱导培养后,成骨相关基因的表达水平均较诱导前明显上调（P<0.05）,SDF-1在50、200 ng·mL ^-1时分别对iPDLSCs和hPDLSCs细胞成骨分化作用最明显（P<0.05）。结论 正常来源和炎症来源的人牙周膜干细胞均具有成骨分化能力,SDF-1可增强两种来源的牙周膜干细胞的成骨分化能力。     

Alveolar Bone Resorption Induced by CD4+CD45RB High‐Density T‐Cell Transfer in Immunocompromised Mice

Background: The aims of this study are to determine whether the antigen‐inexperienced (naive, CD45RB high‐density) T‐cell (CD4⁺CD45RB^High T‐cell) transfer model is associated with alveolar bone resorption, to elucidate the local osteogenic/adipogenic potential of alveolar bone marrow stromal cells (ABCs) from T‐cell–transferred animals, and to investigate the systemic osteogenic potential by transplanting human periodontal ligament stem cells (hPDLSCs) into these animals. Methods: CD4⁺CD45RB^High and CD4⁺CD45RB^Low (antigen‐experienced [memory, CD45RB low‐density]) T cells were sorted and transferred into severe combined immunodeficiency (SCID) mice to induce inflammatory bowel disease–like syndrome (n = 8). hPDLSCs were transplanted into T‐cell–transferred SCID mice to examine ectopic cementum formation 8 weeks after T‐cell transfer. The mandibles and tibias of these mice were retrieved for microcomputed tomography (micro‐CT), histomorphometric analysis, and isolation of ABCs 16 weeks after T‐cell transfer. The in vitro osteogenic and adipogenic potentials of the ABCs were evaluated. Results: Histologic and micro‐CT analysis revealed that the transfer of CD4⁺CD45RB^High T‐cell subset was sufficient for alveolar bone resorption and affected the osteogenic/adipogenic potential of ABCs. Furthermore, it was found that CD4⁺CD45RB^High T‐cell–transferred animals have decreased systemic osteogenic potential, as evidenced using the in vivo ectopic hPDLSC transplantation model. Conclusion: CD4⁺CD45RB^High T‐cell transfer induced both alveolar bone resorption and reduced systemic osteogenic potential, with a concomitant downregulation of the osteogenic potential of ABCs.     

GAS5靶向miR-222-3p对牙周膜干细胞成骨分化的影响机制

成骨诱导hPDLSCs后,茜素红染色显示矿化增强GAS5表达升高(P<0.05),Runx2、ALP和OCN mRNA表达降低,miR-222-3p表达升高(P<0.05);miR-222-3p抑制剂可逆转GAS5低表达对hPDLSCs的作用(P<0.05).提示hPDLSCs成骨分化后GAS5表达上调,下调GAS5可...     

P2X7受体在人牙周膜干细胞成骨分化中的作用

目的：探讨P2X7受体（P2X7 receptor,P2X7r）在人牙周膜干细胞成骨分化中的作用。方法：选取就诊于贵州中医药大学第一附属医院的健康青年患者因正畸需要而拔除的前磨牙为实验材料,分离、培养人牙周膜干细胞（human periodontal ligament stem cells,hPDLSCs）。取第4代hPDLSCs,分为A、B、C、D 4组,A组用常规培养液培养,B组用成骨诱导液培养,C组用成骨诱导液+100 nmol/L三磷酸腺苷（adenosine triphosphate,ATP）溶液培养,D组用成骨诱导液+100 nmol/L P2X7受体特异性拮抗剂KN-62培养。7 d后,采用茜素红染色观察各组hPDLSCs成骨效果,采用实时荧光定量反转录PCR（RT-PCR）检测各组hPDLSCs成骨相关因子骨钙素（osteocalcin,OCN）、RUNX2 mRNA的表达量,采用RT-PCR检测各组hPDLSCs中P2X7r mRNA表达。采用SPSS 22.0软件包对结果进行统计学分析。结果：茜素红染色结果显示,B组和C组hPDLSCs细胞形态发生显著变化,逐渐由不规则形变为方形,出现灰白色钙化小结节。结节多呈板层状圆形或椭圆形团块,C组灰白色钙化小结节显著多于B组,而A组和D组钙结节量均很少。B、C组hPDLSCs中OCN、RUNX2、P2X7r mRNA表达量显著高于A组（P<0.05）,C组hPDLSCs中OCN、RUNX2、P2X7r mRNA表达量显著高于B组（P<0.05）,D组hPDLSCs中OCN、RUNX2、P2X7r mRNA表达量显著低于B、C组（P<0.05）,D组hPDLSCs中OCN、RUNX2、P2X7r mRNA表达量与A组相比,差异无统计学意义（P>0.05）。结论： P2X7受体在人牙周膜干细胞成骨分化中发挥正调节作用。P2X7受体被ATP激活后,可促进人牙周膜干细胞成骨分化,这为临床上治疗牙周炎提供了新的方向。     

经典Wnt信号通路与牙周膜干细胞成骨分化

牙周炎是口腔最常见的疾病之一,累及牙周支持组织,随着疾病的进展将引起附着丧失、牙周袋形成、牙槽骨吸收,最终导致牙齿松动脱落。因被牙周炎破坏吸收的牙槽骨自愈能力十分有限,所以牙周炎的治疗目标是在彻底清除菌斑生物膜的基础上,争取获得较多的牙周组织再生。牙周膜干细胞作为最适宜进行牙周组织再生的细胞,被广泛研究。Wnt信号通路分为经典Wnt通路和非经典Wnt信号通路,为十分复杂而高度保守的通路传导途径。该通路与牙周膜干细胞成骨分化的关系十分密切,牙周膜干细胞的成骨分化又对牙周组织再生有重要意义。该文对经典Wnt信号通路与牙周膜干细胞成骨分化的研究概况作一综述。     

人脐带Wharton's Jelly来源间充质干细胞与人牙周膜干细胞成骨分化能力的对比研究

目的:比较人脐带Wharton's Jelly来源间充质干细胞(human umbilical cord Wharton's Jelly-derived mesechymal stem ceils,hUCWJMSCs)与人牙周膜干细胞(periodontal mesenchymal stem cells,hPDLSCs)成骨分化能力.方法:体外培养hUC-WJMSCs和hPDLSCs.MTT法检测细胞增殖情况;成骨诱导后测定细胞的ALP活性,茜素红染色检测细胞矿化能力,Real-timePCR分析OPN和Runx2基因的表达.结果:hUCWJMSCs增殖能力高于hPDLSCs;经矿化诱导后hPDLSCs ALP表达、矿化结节形成高于hUCWJMSCs(P＜0.05);Runx2在hPDLSCs中表达高于hUCWJMSCs(P ＜0.05);而hUCWJMSCs中OPN表达高于hPDLSCs(P＜0.05).结论:hUCWJMSCs、hPDLSCs均具有成骨分化能力,hPDLSCs成骨分化能力较强.     

颌骨骨髓基质细胞与牙周膜细胞的生物学特性比较

目的:比较颌骨骨髓基质细胞与牙周膜细胞的基本生物学特性。方法:分离颌骨来源骨髓基质细胞和牙周膜细胞,进行改良体外原代培养。倒置显微镜观察细胞生长及克隆形成情况;CCK-8检测细胞生长曲线;免疫荧光染色检测STR0-1表达;成脂诱导后检测脂滴形成,矿化诱导后检测碱性磷酸酶的变化并用RT-PCR检测7、14 d成骨相关基因OCN的表达水平。结果:两种细胞体外培养均呈成纤维样细胞外形,能克隆生长,均具有活跃的增殖能力;两种细胞STR0-1表达阳性;成脂诱导后可见脂滴形成;矿化诱导后骨髓基质细胞的碱性磷酸酶活性较强,而且OCN基因表达较早且较强。结论:颌骨来源骨髓基质细胞具有较强的增殖及成骨分化能力,具有干细胞特性,可能是有较大临床应用潜力的组织工程种子细胞。     

The dynamic healing profile of human periodontal ligament stem cells: histological and immunohistochemical analysis using an ectopic transplantation model

Kim Y‐T, Park J‐C, Choi S‐H, Cho K‐S, Im G‐I, Kim B‐S, Kim C‐S. The dynamic healing profile of human periodontal ligament stem cells: histological and immunohistochemical analysis using an ectopic transplantation model. J Periodont Res 2012; 47: 514–524. © 2012 John Wiley & Sons A/S Background and Objective: Human periodontal ligament stem cells (hPDLSCs) have been reported to play the pivotal role in periodontal regeneration. However, the dynamic cellular healing process initiated by hPDLSCs still remains to be elucidated. In the present study, the sequence of regeneration by hPDLSCs was assessed using histological and immunohistochemical observation in an ectopic transplantation model, which is a well‐standardized assessment tool that excludes the innate healing factors from the animals. Material and Methods: Human periodontal ligament stem cells that were isolated and characterized from teeth (n = 12) extracted for the purpose of orthodontic treatment were transplanted with carriers into ectopic subcutaneous pouches in immunocompromised mice (n = 20). Animals were killed after several different healing periods: 3 d (n = 4), 1 (n = 4), 2 (n = 4), 4 (n = 4) and 8 wk (n = 4). Histological analysis for regenerated tissues formed by hPDLSCs was conducted using hematoxylin and eosin, Masson’s trichrome and picrosirius red staining. In addition, immunohistochemical staining was performed to observe the sequential expression of osteogenic/cementogenic and periodontal ligament tissue‐specific markers associated with periodontal regeneration. Results: The whole healing process by transplanted hPDLSCs could be broadly divided into four distinctive phases. In the first phase, proliferated hPDLSCs migrated evenly all over the carrier, and collagenous tissues appeared in the form of amorphous collagen matrices. In the second phase, collagen fibers were well arranged among the carriers, and cementoid‐like tissues were observed. In the third phase, the formation of mature collagen fibers, resembling Sharpey’s fibers, was associated with active mineralization of cementum‐like tissues, and in the fourth phase, the maturation of cementum‐like tissues was observed on carrier surfaces. Various osteogenic/cementogenic markers related to the regeneration processes were expressed in a well‐orchestrated time order. Interestingly, well‐organized cementum‐like and periodontal ligament fiber‐like tissues and cells with early and late osteogenic/cementogenic markers were frequently observed in the secluded area of carrier surfaces. We termed this area the cell‐rich zone. Conclusion: The results from this study clearly demonstrated the sequential histological changes during periodontal tissue regeneration by hPDLSCs. Understanding of this process would potentially enable us to develop better cell‐based treatment techniques.     

煅烧牙粉影响人牙周膜干细胞体外矿化的自噬机制研究

目的 探讨自噬在煅烧牙粉调节牙周膜干细胞体外矿化中的作用,为牙周膜干细胞的定向诱导分化和牙周病的治疗提供参考。方法 选用成人完整的牙齿在300 ℃的条件下煅烧后,研磨成粉,与α-MEM混合制备成20 μg/mL牙粉条件培养基,与人牙周膜干细胞共培养。采用流式细胞技术检测其对牙周膜干细胞凋亡的影响,通过Western blot检测、免疫荧光染色、茜素红染色和ALP染色观察检测其对牙周膜干细胞自噬活性及体外矿化的影响。结果 流式细胞技术结果显示牙粉对牙周膜干细胞的凋亡无明显影响（P＞0.05）;Western blot结果显示煅烧牙粉显著上调人牙周膜干细胞的自噬相关蛋白Beclin1,ATG5的表达和LC3Ⅱ/LC3Ⅰ的比值,以及明显下调了P62的蛋白水平（P<0.05）;免疫荧光染色显示牙粉促进人牙周膜干细胞中LC3在胞质内点状聚集;茜素红染色显示牙粉促进牙周膜干细胞的体外矿化;ALP染色显示自噬活性抑制剂氯喹降低牙粉对牙周膜干细胞体外矿化的促进作用。结论 煅烧牙粉通过激活自噬调节牙周膜干细胞的体外矿化作用。     

低强度高频振动对人牙周膜干细胞成骨分化能力的影响

目的 研究低强度高频振动（low-magnitude high frequency vibration,LMHFV）对人牙周膜干细胞（human periodontal ligament stem cells,hPDLSCs）增殖、迁移、成骨分化能力的影响。方法 体外分离培养hPDLSCs;流式细胞术检测间充质干细胞表面标志物;加载LMHFV（加速度=0.3 g,频率=40 Hz,时间=15 min/24 h）刺激后,采用CCK-8试剂盒检测细胞增殖能力,通过细胞划痕实验检测细胞迁移能力;通过qRT-PCR、Western免疫印迹检测成骨相关基因、蛋白表达水平,通过茜素红染色检测细胞成骨分化能力。采用SPSS 21.0软件包对数据进行统计学分析。结果 加载振动刺激后,hPDLSCs的增殖能力增强,迁移能力上升;RUNX2、ALP、Col-1、OCN的mRNA表达量和蛋白表达量均上升,茜素红染色结果与qRT-PCR、Western免疫印迹结果一致。结论 LMHFV可提高hPDLSCs的增殖、迁移能力和成骨分化能力。     

长链非编码RNA钾离子电压门控通道亚家族Q成员1重叠转录本1通过靶向miR-24-3p调控人牙周膜干细胞增殖和成骨分化

探讨长链非编码RNA（lncRNA）钾离子电压门控通道亚家族Q成员1重叠转录本1（KCNQ1OT1）对人牙周膜干细胞（hPDLSCs）增殖和成骨分化的影响及分子机制。