Morphostructural analysis of human follicular stem cells on highly porous bone hydroxyapatite scaffold

In this study we investigated the in vitro behaviour, morphostructure and extracellular matrix synthesis of human dental follicular stem cells (hDFSCs) isolated from human dental bud, which resulted to be positive for mesenchymal markers (CD29, CD90, CD146 and CD166) by FACS analysis. Cells were analysed by light and electronic microscopy to evaluate their biological response either at week 1, that is before differentiation, or at weeks 3-6, when they had been cultured in osteogenic medium onto a highly porous natural scaffold material (Bio-Oss). Microscopy analysis of primary culture cells showed they had a mesenchymal stem cell-like morphostructure, spindle shaped, similar to the culture of mesenchymal stem cells derived from adult bone marrow. Also, after osteogenic differentiation, these analyses indicate typical osteoblast morphostructure and reveale a tri-dimensional organization of the cells and deposition of extracellular matrix (ECM) in close contact with biomaterial. This approach would allow to personalize the scaffold for bone tissue engineering in order to accelerate the process of osteogenesis.     

Microsphere-based drug releasing scaffolds for inducing osteogenesis of human mesenchymal stem cells in vitro

In this study, in vitro osteogenesis was successfully achieved in human mesenchymal stem cells (hMSCs) by controlled release of the osteogenesis-inducing drugs dexamethasone, ascorbic acid (AA) and β-glycerophosphate (GP) from poly(lactic-co-glycolic acid) (PLGA) sintered microsphere scaffolds (SMS). We investigated the osteogenesis of human MSCs (hMSCs) on dexamethasone laden PLGA-SMS (PLGA-Dex-SMS), and dexamethasone, AA and GP laden PLGA-SMS (PLGA-Com-SMS). hMSCs cultured on the microsphere systems, which act as drug release vehicles and also promote cell growth/tissue formation—displayed a strong osteogenic commitment locally. The osteogenic commitment of hMSCs on the scaffolds were verified by alkaline phosphatase (ALP) activity assay, calcium secretion assay, real-time PCR and immunohistochemistry analysis. The results indicated hMSCs cultured on PLGA-Com-SMS exhibited superior osteogenic differentiation owing to significantly high phenotypic expression of typical osteogenic genes—osteocalcin (OC), type I collagen, alkaline phosphatase (ALP), and Runx-2/Cbfa-1, and protein secretion of bone-relevant markers such as osteoclast and type I collagen when compared with PLGA-Dex-SMS. In conclusion, by promoting osteogenic development of hMSCs in vitro, this newly designed controlled release system opens a new door to bone reparation and regeneration.     

Differentiation of human osteoprogenitor cells increases after treatment with pulsed electromagnetic fields

Human mesenchymal stem cells (hMSC) have become an important resource in developing strategies for regenerative medicine and tissue engineering, owing to their ability to renew and their potential for differentiation into cells of various types of tissues. Pulsed electromagnetic field (PEMF) stimulation has been used for several years in the treatment of fracture healing, with clinical beneficial effects, and several studies have demonstrated its capacity to increase bone tissue regeneration. In the present study, stromal cells of human bone marrow (BMSC), obtained from healthy donors, were appropriately expanded and underwent PEMF stimulation eight hours a day for fourteen days. Parameters such as proliferation and differentiation ability were evaluated on stimulated cultures. The evaluation of the marker expression was performed by RT-PCR for osteocalcin, by alkaline phosphatase quantitation and by histochemical stains. The results we obtained showed that BMSC treated with PEMF begin differentiation earlier than untreated BMSC, as shown by the markers used. The data show that PEMF is able to increase the osteogenic differentiation potential in adult mesenchymal cells isolated from young patients.     

Assessing the effect of triethyleneglycol dimethacrylate on tissue repair in 3D organotypic cultures

Leachables from dental restoratives induce toxicity in gingival and pulp tissues and affect tissue regeneration/healing. Appropriate testing of these materials requires a platform that mimics the in vivo environment and allows the architectural self‐assembly of cells into tissue constructs. In this study, we employ a new 3D model to assess the impact of triethyleneglycol dimethacrylate (TEGDMA) on early organization and advanced recruitment/accumulation of immortalized mouse gingival fibroblasts (GFs) and dental papilla mesenchymal cells (DPMCs) in extracellular matrix. We hypothesize that TEGDMA (1) interferes with the developmental architecture of GFs and DPMCs, and (2) inhibits the deposition of mineral. To test these hypotheses, GFs and DPMCs were incubated with the soluble TEGDMA at concentrations (0‐2.5) mmol/L. Diameter and thickness of the constructs were determined by microscopic analysis. Cell differentiation was assessed by immunocytochemistry and the secreted mineral detected by alizarin‐red staining. TEGDMA interfered with the development of GFs and/or DPMCs microtissues in a dose‐dependent manner by inhibiting growth of inter‐spherical cell layers and decreasing spheroid size (four to six times). At low/moderate TEGDMA levels, GFs organoids retained their structures while reducing thickness up to 21%. In contrast, at low TEGDMA doses, architecture of DPMC organoids was altered and thickness decreased almost twofold. Overall, developmental ability of TEGDMA‐exposed GFs and DPMCs depended on TEGDMA level. GFs constructs were more resistant to structural modifications. The employed 3D platform was proven as an efficient tool for quantifying the effects of leachables on tissue repair capacities of gingiva and dental pulp.     

合成成骨生长肽对人骨髓间充质干细胞的促成骨作用

目的研究合成成骨生长肽（sOGP）对人骨髓间充质干细胞（BMSCs）分化的影响。方法分离BMscs进行体外培养,加入不同浓度的sOGP,观察细胞形态变化,RT-PCR法检测3种主要成骨标志物[碱性磷酸酶（ALP）、Ⅰ型胶原、骨钙素]的表达,组织化学染色检测ALP、Ⅰ型胶原的表达及钙质的沉积并进行图像分析。结果sOGP在mRNA和蛋白水平均能促进各成骨标志物的表达,定量分析结果显示,sOGP在10^-9mol／L浓度组促成骨的作用最强。结论sOGP能促进入BMSCs向成骨方向转化。这种促成骨能力与其浓度密切相关,以10^-9mol／L浓度促成骨能力最强。     

BoneCeramic和Bio-Oss骨粉对狗骨髓间充质干细胞体外成骨分化能力影响的比较研究

目的比较BoneCeramic和Bio-Oss骨粉对狗骨髓间充质干细胞(DBMSCs)的增殖、黏附和体外成骨分化能力的影响。方法体外分离培养DBMSCs并进行成骨、成脂分化鉴定;CCK-8检测BoneCeramic和Bio-Oss两种骨粉浸提原液对DBMSCs活力的影响;SEM观察细胞在骨粉表面的黏附情况;ALP定量检测细胞在骨粉表面的成骨分化能力,RT-PCR检测OPN、OCN、RUNX-2和ALP基因的相对表达情况。结果从狗骨髓中分离培养的细胞符合间充质干细胞的特征;CCK-8结果显示两种骨粉浸提液均对DBMSCs没有明显的细胞毒性作用;SEM结果显示,与Bio-Oss相比,DBMSCs在BoneCeramic的表面分布更广;ALP定量检测显示DBMSCs在BoneCeramic表面比Bio-Oss更有利于其成骨分化,同时使OPN、OCN、RUNX-2和ALP基因的表达升高。结论体外研究表明,Bio-Oss和BoneCeramic均具有良好的生物相容性,与Bio-Oss骨粉相比,BoneCeramic更加有利于DBMSCs的成骨分化。     

Icariin regulates miR-23a-3p-mediated osteogenic differentiation of BMSCs via BMP-2/Smad5/Runx2 and WNT/β-catenin pathways in osteonecrosis of the femoral head

Icariin is commonly used for the clinical treatment of osteonecrosis of the femoral head (ONFH). miR-23a-3p plays a vital role in regulating the osteogenic differentiation of bone marrow-derived mesenchymal stem cells (BMSCs). The present study aimed to investigate the roles of icariin and miR-23a-3p in the osteogenic differentiation of BMSCs and an ONFH model. BMSCs were isolated and cultured in vitro using icariin-containing serum at various concentrations, and BMSCs were also transfected with a miR-23a inhibitor. The alkaline phosphatase (ALP) activity and cell viability as well as BMP-2/Smad5/Runx2 and WNT/β-catenin pathway-related mRNA and protein expression were measured in BMSCs. Additionally, a dual-luciferase reporter assay and pathway inhibitors were used to verify the relationship of icariin treatment/miR-23a and the above pathways. An ONFH rat model was established in vivo, and a 28-day gavage treatment and lentivirus transfection of miR-23a-3p inhibitor were performed. Then, bone biochemical markers (ELISA kits) in serum, femoral head (HE staining and Digital Radiography, DR) and the above pathway-related proteins were detected. Our results revealed that icariin treatment/miR-23a knockdown promoted BMSC viability and osteogenic differentiation as well as increased the mRNA and protein expression of BMP-2, BMP-4, Runx2, p-Smad5, Wnt1 and β-catenin in BMSCs and ONFH model rats. In addition, icariin treatment/miR-23a knockdown increased bone biochemical markers (ACP-5, BAP, NTXI, CTXI and OC) and improved ONFH in ONFH model rats. In addition, a dual-luciferase reporter assay verified that Runx2 was a direct target of miR-23a-3p. These data indicated that icariin promotes BMSC viability and osteogenic differentiation as well as improves ONFH by decreasing miR-23a-3p levels and regulating the BMP-2/Smad5/Runx2 and WNT/β-catenin pathways.     

miR-21对绝经后骨质疏松骨髓间充质干细胞成骨能力影响的研究

目的 探讨miR-21对绝经后骨质疏松骨髓间充质干细胞（PMOP-hBMMSC）成骨能力影响.方法 分离培养正常人（H-hBMMSCs）和绝经后骨质疏松患者（PMOP-hBMMSCs）的骨髓间充质干细胞,并对两组细胞的成骨能力进行比较.转染上调PMOP-hBMMSCs中miR-21表达,观察分析其对成骨能力的影响.Real time RT-PCR和Western Blot比较miR-21在三组细胞间的表达差异,同时检测三组成骨标志性基因Runx2和Osterix的表达.结果 PMOP-hBMMSCs组中的miR-21表达水平、ALP的活性以及钙结节染色面积都高于PMOP组（P＜0.05）,与H-hBMMSCs正常对照组差异无统计学意义（P＞0.05）;RT-PCR和Western Blot结果显示成骨诱导7d后,转染后高表达Runx2和Osterix mRNA和蛋白水平均高于PMOP组（P＜0.05,P＜0.01）,与H-hBMMSCs正常对照组差异无统计学意义（P＞0.05）.结论 转染miR-21后的PMOP-hBMMSCs成骨能力增强.     

诱导人骨髓间充质干细胞向成骨细胞分化

目的探讨人骨髓间充质干细胞(mesenchymal stem cells，MSCs)向成骨细胞诱导分化的能力。方法选用不同代次的MSCs，使用条件培养基，观察细胞的形态变化，采用细胞化学和免疫组化的方法检测碱性磷酸酶、钙盐沉积及Ⅰ型胶原的表达。结果MSCs在条件培养基中，15d后可见细胞变为多边形，碱性磷酸酶和Ⅰ型胶原染色阳性，形成钙结节，表现成骨细胞分化特点。结论在一定培养条件下成功诱导人MSCs向成骨细胞分化。在骨组织工程学方面MSCs作为种子细胞具有潜在的应用价值。     

Biological characterization of long-term cultured human mesenchymal stem cells

Human mesenchymal stem cells (hMSCs) have generated a great deal of interest in clinical applications. The reason is that they may have the plasticity needed to differentiate into multiple lineages and the ability to expand ex vivo. For the therapeutic applications of hMSCs to be of practical use, it is crucial to assess the efficacy and safety of hMSCs in long-term ex vivo expansion. In this study, we cultured hMSCs by population doubling (PD) 60, and investigated their growth, osteogenic and adipogenic differential abilities, change of surface markers, telomerase activity, telomere length, and gene expression related to tumorigenesis. An in vivo tumorigenesis assay was also carried out. In long-term expanded hMSCs, the cells became aged above PD 30 and their adipogenic and osteogenic differentiation potential decreased. Telomerase activity unchanged whereas telomere length decreased and karyotypes were not changed. Gene expressions related to tumorigenesis decreased in proportion as the PD of hMSCs increased. In vivo transplantation of long-term cultured hMSCs to nude mice did not result in tumor formation. These findings suggest that diverse tests for cellular therapy should be considered during the ex vivo culture of hMSCs, particularly when a prolonged and extended propagation period is required.     

Icariin regulates miR-23a-3p-mediated osteogenic differentiation of BMSCs via BMP-2/Smad5/Runx2 and WNT/β-catenin pathways in osteonecrosis of the femoral head

Icariin is commonly used for the clinical treatment of osteonecrosis of the femoral head (ONFH). miR-23a-3p plays a vital role in regulating the osteogenic differentiation of bone marrow-derived mesenchymal stem cells (BMSCs). The present study aimed to investigate the roles of icariin and miR-23a-3p in the osteogenic differentiation of BMSCs and an ONFH model. BMSCs were isolated and cultured in vitro using icariin-containing serum at various concentrations, and BMSCs were also transfected with a miR-23a inhibitor. The alkaline phosphatase (ALP) activity and cell viability as well as BMP-2/Smad5/Runx2 and WNT/β-catenin pathway-related mRNA and protein expression were measured in BMSCs. Additionally, a dual-luciferase reporter assay and pathway inhibitors were used to verify the relationship of icariin treatment/miR-23a and the above pathways. An ONFH rat model was established in vivo, and a 28-day gavage treatment and lentivirus transfection of miR-23a-3p inhibitor were performed. Then, bone biochemical markers (ELISA kits) in serum, femoral head (HE staining and Digital Radiography, DR) and the above pathway-related proteins were detected. Our results revealed that icariin treatment/miR-23a knockdown promoted BMSC viability and osteogenic differentiation as well as increased the mRNA and protein expression of BMP-2, BMP-4, Runx2, p-Smad5, Wnt1 and β-catenin in BMSCs and ONFH model rats. In addition, icariin treatment/miR-23a knockdown increased bone biochemical markers (ACP-5, BAP, NTXI, CTXI and OC) and improved ONFH in ONFH model rats. In addition, a dual-luciferase reporter assay verified that Runx2 was a direct target of miR-23a-3p. These data indicated that icariin promotes BMSC viability and osteogenic differentiation as well as improves ONFH by decreasing miR-23a-3p levels and regulating the BMP-2/Smad5/Runx2 and WNT/β-catenin pathways.     

人牙龈成纤维细胞和牙周膜韧带细胞多向分化潜能的比较

目的 体外培养人牙周膜韧带细胞 （HPDLCs） 和人牙龈成纤维细胞 （HGFs）, 对比两者成骨、 成软骨以及成脂的多向分化潜能的差异。方法 运用酶消化结合组织块法体外培养 HPDLCs 和 HGFs, 选择生长状态良好的 3~4 代 HPDLCs 和 HGFs, 进行成骨、 成软骨、 成脂诱导, 未分化诱导的细胞作为对照组。分别用茜素红染色、 油红 O 染色以及阿利新蓝染色分别检测两种细胞的成骨、 成软骨及成脂分化能力。半定量逆转录聚合酶链反应 （RT-PCR） 检测 HPDLCs 和 HGFs 中相关标志基因骨钙素(OCN)、 Ⅰ型胶原蛋白 （Col 1）、 runt 相关转录因子 2 （RUNX2）、 过氧化物酶体增殖物激活受体γ2 （PPARγ2）、 X 型胶原蛋白 （Col 10） mRNA 的表达。结果 成骨诱导两种细胞培养至 28 d 时, 细胞周围均有红染钙结节形成, HPDLCs 形成的钙结节明显多于 HGFs; 成软骨诱导两种细胞 14 d 时均可见胞质蓝染的细胞, HGFs 较 HPDLCs 明显; 成脂诱导两种细胞 21 d 时, 可见红色脂肪滴形成, HPDLCs 形成的脂肪颗粒明显少于 HGFs。HGFs 和 HPDLCs 分化培养 7 d 和 14 d 后, 均有 OCN、 Col 1、 RUNX2、 PPARγ2 和 Col 10 的表达, 在 14 d 时的表达均高于 7 d; HPDLCs 中 OCN、 Col 1、 RUNX2 的表达高于 HGFs, PPARγ2、 Col 10 的表达低于 HGFs（均 P＜ 0.05）。结论 HPDLCs 的成骨能力较 HGFs 强, 成软骨和成脂能力较 HGFs 弱。     

Current topics in pharmacological research on bone metabolism: Promyelotic leukemia zinc finger (PLZF) and tumor necrosis factor-alpha-stimulated gene 6 (TSG-6) identified by gene expression analysis play roles in the pathogenesis of ossification of the posterior longitudinal ligament

To understand the molecular pathogenesis of ossification of the posterior longitudinal ligament of the spine (OPLL), an ectopic bone formation disease, we performed cDNA microarray analysis on cultured ligament cells from OPLL patients to understand the molecular pathogenesis of OPLL. We identified promyelotic leukemia zinc finger (PLZF) as one of up-regulated genes and tumor necrosis factor-alpha-stimulated gene 6 (TSG-6) as one of down-regulated gene during osteoblastic differentiation. We investigated the roles of PLZF in the regulation of osteoblastic differentiation of human mesenchymal stem cells (hMSCs) and C2C12 cells. siRNA-mediated gene-silencing of PLZF resulted in a reduction of the expression of osteoblast-specific genes such as the alkaline phosphatase, collagen 1A1, Runx2/CBFA1, and osteocalcin genes in the presence of osteogenic differentiation medium (OS) in hMSCs. The overexpression of PLZF induced CBFA1 induction, suggesting that PLZF is an upstream regulator of CBFA1 and thereby participates in promoting the ossification of spinal ligament cells in OPLL patients. Adenovirus-mediated TSG-6 overexpression in hMSCs resulted in suppression of osteoblastic differentiation induced by either BMP-2 or OS. TSG-6 can bind to BMP-2 directly and thereby could inhibit BMP-2 signaling. Taken together, these findings indicate that PLZF and TSG-6 play important roles in early osteoblastic differentiation.     

Bone biomimetic microenvironment induces osteogenic differentiation of adipose tissue-derived mesenchymal stem cells

A critical strategy for tissue engineering is to provide the signals necessary for tissue regeneration by mimicking the tissue microenvironment. In this study, we mimicked (1) the bone chemical and the physical microenvironment by fabricating a three-dimensional nanocomposite scaffold composed of biphasic calcium phosphates (BCP) coated with a nanocomposite layer of polycaprolactone (PCL) and hydroxyapatite nanoparticles (nHA) (BCP/PCL-nHA)), and (2) the bone's biological microenvironment by co-culturing with primary human osteoblasts (HOBs), and then investigated their effects on osteogenic differentiation of adipose tissue-derived stem cells (ASCs). In comparison with the ASCs cultured alone on BCP scaffolds that were coated only with PCL, early osteogenic differentiation of ASCs was induced by either seeding ASCs on BCP/PCL-nHA scaffolds or by co-culturing with HOBs; the combination of BCP/PCL-nHA scaffold and HOBs resulted in the synergistic enhancement of osteogenic gene expression. Moreover, we found that BCP/PCL-nHA scaffolds induced early osteogenic differentiation of ASCs through integrin-α2 and an extracellular signal-regulated kinase (ERK) signaling pathway. FROM THE CLINICAL EDITOR: The authors mimicked the physico-chemical environment of bone by fabricating a nanocomposite scaffold, and then co-cultured it with human osteoblasts. Demonstrated enhancement of osteogenic gene expression and early osteogenic differentiation of adipose tissue derived stem cells were found using this approach.     

The changes of iNOS and NO in the osteogenic differentiation process of rat bone marrow stromal cells promoted by icariside II

This study is to investigate the effects on the expression of iNOS and production of NO in the osteogenic differentiation process of rat bone marrow stromal cells (rBMSCs) by icariside II. rBMSCs were cultured by adherence screening method. When the culture dishes were covered with 80% cells, the osteogenic induced cultures were adopted. Icariside II was supplemented into the culture at 1 x 10(-5) mol x L(-1). The activity of iNOS, content of NO and osteogenic differentiation markers including alkaline phosphatase (ALP) activity, CFU-FALP and mineralized bone nodules were compared among the icariside II-supplemented group, L-NMAE group, icariside II + L-NAME group and the control. Total RNA was isolated and the gene expression of iNOS, Osterix and Runx-2 was investigated by real-time PCR. Total protein was also isolated and the secretion of iNOS and collagen I was examined by Western blotting. Icariside II can significantly improved ALP activity, CFU-FALP amount and mineralized nodules. Besides, the mRNA level of factors related to the osteogenic differentiation includes Osterix and Runx-2 also enhanced. The secretion of collagen I also promoted significantly. But all of these effects can be inhibited by L-NAME which can specifically inhibit the activity of iNOS. Icariside II enhances the osteogenic differentiation of rBMSCs significantly, but if the activity of iNOS was blocked by L-NAME, the osteogenic differentiation markers decrease accompanied with iNOS and NO decrease, suggesting that icariside II stimulates the osteogenic differentiation via enhancing the activity of iNOS and promoting the generation of NO.     

Smad6信号干扰对MSCs骨向分化的影响

目的研究Smad6信号干扰对骨形态发生蛋白2（BMP-2）诱导的骨髓间充质干细胞（MSCs）骨向分化的促进效应。方法培养小鼠MSCs,用BMP-2诱导骨向分化。细胞分为3组：A组细胞用携带绿色荧光蛋白（GFP）的Smad6重组RNA干扰载体转染;B组细胞用空白载体转染;C组细胞作为对照。结果病毒转染后GFP在MSCs中有效表达,病毒转染效率达98．5％。与B组比较,Smad6RNA干扰显著提高了A组细胞AIP活性和骨钙素水平（P〈0．01）,而C组ALP活性和骨钙素水平均显著低于其他2组（P〈0．01）。茜素红染色显示,A组矿化结节数目显著多于B组（P〈0．05）,而c组无矿化结节形成。结论Smad6RNA干扰可有效促进BMP-2诱导的MSCs骨向分化,该研究为骨组织工程中骨缺损修复提供了一个极具价值的手段。