人骨髓基质细胞的长期培养及其对病毒的敏感性

为了长期培养骨髓基质细胞和研究其对病毒的敏感性,我们采用静置贴壁培养法,体外长期培养了胎儿、儿童和成人骨髓基质细胞,并将传至５代以上的肌样骨髓基质细胞采用微量细胞病变（ＣＰＥ）法,开展了对５种病毒的敏感性试验。结果表明,人骨髓基质肌样细胞对滤泡性口腔炎病毒,脊髓灰质炎病毒、Ⅰ型和Ⅱ型单纯疱疹病毒均敏感,能产生明显的ＣＰＥ,其效价（ＴＣＩＤ５０）可达１０＾－３～１０＾－４,其中胎儿骨髓基质肌样细胞对     

人体骨髓长期培养中粘壁层的基质细胞

应用免疫荧光技术对人体骨髓长期培养(HLTBMC)粘壁层细胞作了研究,发现在不同的基质细胞中有着下列表面标记:基质成纤维细胞CD 10~+,FIB 86.3~+,CD 13~+,CD 71~+;脂肪细胞CD 10~+,FIB 86.3~+,CD 13~+,CD71~+/-,CD 14~+,CD 33~+,CD 25~+,HLA-DR~+,CD 19~+,CD 5~+,基质成纤维细胞的标记与两次传代的骨髓成纤维细胞以及皮肤和脾脏的成纤维细胞相似。HLTBMC中的成纤维细胞较之非巨噬细胞的小圆形造血细胞,数量上占很大的优势,加之镀银染色发现网状纤维增多,提示HLTBMC后期造血活性的消失可能与临床上的骨髓纤维化有着相似的机理。     

人骨髓基质细胞体外分离及定向培养内皮细胞

用Ficoll(比重1.077 g/ml)从正常成人骨髓中分离骨髓基质细胞(BMSCs),DMEM-HG 培养基内含20?S、GM-CSF(100 u/ml)、VEGF(10 ng/ml)、FGF(5 ng/ml)、L-谷氨酰胺(2mmol/ L)、肝素(90 u/ml),以及抗生素液进行定向培养和扩增其中的内皮细胞(ECs),Ⅷ因子相关抗原的免疫组化法和透射电镜观察(TEM)鉴定其细胞的性质。结果5.0×105个BMSCs在体外经定向ECs 培养和扩增8代后,获得了6.0×109个ECs,扩增了约1.2×104倍。70%-80%的细胞对Ⅷ因子相关抗原免疫组化呈阳性反应;光镜下细胞呈典型的“鹅卵石”样;TEM下可观察到胞浆内有Weible- palade小体,证实为内皮细胞。实验表明,BMSCs在体外分离和定向培养的ECs,经扩增后可能是心血管组织工程所需种子细胞的又一个重要来源。     

人骨髓基质细胞对精原干细胞体外增殖的影响研究

精原干细胞是精子形成的原始细胞,在睾丸组织中的含量极低,而体外有效扩增方法的选择对其移植治疗和抗生育研究十分重要。本实验选用人骨髓基质细胞代替传统饲养层培养人精原干细胞,探讨精原干细胞能否在该饲养层上增殖的可能机制,为人精原干细胞培养提供实验方法和技术指导。骨髓基质饲养层的制备：无菌分离流产5～8月胎儿股骨,     

大鼠骨髓基质细胞的培养及生物学特性鉴定

目的:分离、培养大鼠MSCs,对其生物学特性进行鉴定.方法:取大鼠长骨中的骨髓组织,以贴壁法培养分离大鼠MSCs,经多次传代得到较纯的MSCs,倒置相差显微镜下观察细胞形态,应用免疫细胞化学方法对细胞的表面抗原标志进行检测.取3代MSCs,B-ME诱导6小时候后,倒置相差显微镜下观察细胞形态,应用免疫细胞化学方法鉴定诱导后细胞的表型特征.结果:倒置相差显微镜观察发现,接种后24h,细胞开始贴壁.培养3代以后,细胞呈梭形或多角形,折光性好,核为圆形、居中.免疫细胞化学检测细胞表面抗原显示:CD34-、CD45-、CD29+、CD44+、CD90+.诱导后细胞发出突起,逐渐生长延伸并彼此相连,形态学上具有神经细胞的明显特征.免疫细胞化学显示诱导后细胞NSE(神经元特异性烯醇化酶)阳性.结论:所采用的细胞分离培养方法简便可行,所获得的细胞其表型特征与文献报道一致,且具有向神经细胞分化的潜能.     

壳聚糖及其改性材料对骨髓基质细胞的作用

壳聚糖是一种广泛应用的生物可降解材料,该论文研究了几种与壳聚糖相关的材料对骨髓基质细胞生长和分化的作用,主要实验方法是在材料表面培养骨髓基质细胞并对其进行诱导促使其向成骨细胞方向分化。通过对细胞生长和分化情况的观察和测定,对几种材料与骨髓基质细胞的亲和性作出了评价。另外,通过ELISA法测定了细胞外基质分子在材料上的吸附量,测量了各材料的表面接触角以研究细胞在材料表面的铺展和增殖。结果表明尽管壳聚糖本身与骨髓基质细胞并不具有很好的亲和性,但通过与明胶混合,壳聚糖的生物相容性得到了明显提高,是很有应用前景的骨修复材料。     

骨髓基质细胞的辐射效应及其临床意义

小鼠骨髓基质细胞团在γ线照射后的Do值为2.40Gy,但其成灶能力损伤后持续时间较久。正常骨髓基质细胞能促进骨髓GM-CFU-C的生长;照射10-80Gy后的骨髓基质细胞失去这种促进作用。文中讨论了骨髓基质细胞的辐射效应及其临床意义,提出了谨慎选择放射治疗剂量的必要性。     

骨髓基质细胞的特征及其在细胞和基因治疗中的应用

骨髓基质细胞是一类独特的间质干细胞,可分化为多种非造血系的组织。骨髓基质细胞具有贴壁生长的特性,因而易于在体外分离和扩增;另外骨髓基质细胞可在体内外表达多种治疗性的外湖目的基因。因此,骨髓基质细胞被认为是一种理想的治疗性细胞的基因治疗中的靶细胞。本文对骨髓基质细胞的研究进展及其在细胞和基因治疗中的应用作一综述。     

逆转录病毒介导的人血小板生成素(TPO)在骨髓基质细胞中的表达

为探讨逆转录病毒介导的TPO基因在人骨髓基质细胞系HFCL中的表达,利用脂质体法将含TPO基因的逆转录病毒载体导入HF-CL细胞中,RT-PCR和基因组DNAPCR分析证实mRNA水平有表达,基因组中整合有Neo基因和TPO基因。TPO依赖细胞株TD-3检测生物学活性表明转染的骨髓基质细胞分泌TPO。上述结果为进一步研究转基因骨髓基质细胞对造血细胞的调控作用提供了必要的基础资料。     

The aggregate nature of human mesenchymal stromal cells in native bone marrow

Background aims. The clinical application of mesenchymal stromal cells (MSC) faces several obstacles, such as the lack of a standard method for direct isolation as well as a low frequency and concern about the safety of their in vitro expansion. Although the density-gradient separation technique is used as the first step in most methods of MSC isolation to enrich mononuclear cells, the efficiency of this method has not so far been examined. This study was designed to address this issue. Methods. Human bone marrow (BM) samples were laid over Ficoll-Paque, and after centrifugation the upper and lower fractions were cultured separately. Surface markers, differentiation potential and the number of emerged cells were determined. Results. The isolated cells from both the upper and lower fractions were characteristic of MSC. Although it is commonly believed that MSC are single suspending mononuclear cells and so are enriched in the upper fraction of Ficoll-Paque after density-gradient separation, our data showed that considerable numbers of these cells were accumulated in the lower fraction. Further data indicated that MSC were actually present as cell aggregates in BM and they could be enriched effectively by a simple filtration method. Conclusions. The aggregate nature of MSC in BM is in agreement with the concept that they are one of the main elements of the hematopoietic stem cell niche. In addition, the simple filtration method proposed here to isolate cell aggregates may provide opportunities for instant stem cell therapy without the need for extensive in vitro expansion.     

Characterization of the in vitro stromal microenvironment of human bone marrow

Utilizing long-term in vitro culture techniques, we characterized the cellular composition and functional attributes of the human in vitro bone marrow stromal microenvironment. Morphologic, specific cytochemical and immunologic methods demonstrated that the marrow stromal adherent layer (AL) reached confluency at two to three weeks, and was comprised of 60%-70% fibroblastic cells, 10%-20% endothelial cells, 10%-20% monocyte/macrophages and 5%-10% fat-laden adherent cells. These proportions of cell types persisted for at least three months concomitant with proliferation of CFU-gm and BFU-e. In contrast, umbilical cord blood cells did not form a stromal AL despite persistence of hemopoietic progenitor cell proliferation. These findings provide a basis for improved understanding of cellular interactions regulating hemopoiesis.     

Real-time quantitative RT-PCR analysis of human bone marrow stromal cells during osteogenic differentiation in vitro

We developed and used real-time RT-PCR assays to investigate how the expression of typical osteoblast-related genes by human bone marrow stromal cells (BMSC) is regulated by (i) the culture time in medium inducing osteogenic differentiation and (ii) the previous expansion in medium enhancing cell osteogenic commitment. BMSC from six healthy donors were expanded in medium without (CTR) or with fibroblast growth factor-2 and dexamethasone (FGF/Dex; these factors are known to increase BMSC osteogenic commitment) and further cultivated for up to 20 days with ascorbic acid, beta-glycerophosphate and dexamethasone (these factors are typically used to induce BMSC osteogenic differentiation). Despite a high variability in the gene expression levels among different individuals, we identified the following statistically significant patterns. The mRNA levels of bone morphogenetic protein-2 (BMP-2), bone sialo protein-II (BSP), osteopontin (OP) and to a lower extent cbfa-1 increased with culture time in osteogenic medium (OM), both in CTR- and FGF/Dex-expanded BMSC, unlike levels of alkaline phosphatase, collagen type I, osteocalcin, and osteonectin. After 20 days culture in OM, BMP-2, BSP, and OP were more expressed in FGF/Dex than in CTR-expanded BMSC (mRNA levels were, respectively, 9.5-, 14.9-, and 5.8-fold higher), unlike all the other investigated genes. Analysis of single-colony-derived strains of BMSC further revealed that after 20 days culture in OM, only a subset of FGF/Dex-expanded clones expressed higher mRNA levels of BMP-2, BSP, and OP than CTR-expanded clones. In conclusion, we provide evidence that mRNA levels of BMP-2, BSP, and OP, quantified using real-time RT-PCR, can be used as markers to monitor the extent of BMSC osteogenic differentiation in vitro; using those markers, we further demonstrated that only a few subpopulations of BMSC display enhanced osteogenic differentiation following FGF/Dex expansion.     

Glucocorticoid receptor antagonist and siRNA prevent senescence of human bone marrow mesenchymal stromal cells in vitro

We investigate the effects mediated by glucocorticoid (GC) receptor (GR) blockage by using RU486, a GR antagonist and GR short interfering RNA (GR siRNA) on the proliferative and differentiation capabilities of human bone marrow mesenchymal stromal/stem cells (MSCs) and on their senescence and antioxidant levels during extended in vitro culture. Treatment with either RU486 or GR siRNA for a 7-day period significantly increased the proliferation of MSCs and their osteogenic capabilities, as reflected by an increase in alkaline phosphatase (ALP) levels after differentiation. Following 4 weeks of treatment, MSCs improved or maintained their proliferation rates, whereas control MSCs exhibited decreased proliferation. Although all MSCs exhibited reduced osteogenic potential after 4 weeks of in vitro culture, the MSCs treated with GR inhibitors showed higher ALP levels than untreated MSCs on being subjected to osteogenic differentiation. Such treatment also significantly down-regulated the adipogenic capabilities of MSCs. Telomere lengths and the activities of telomerase and superoxide dismutase of MSCs treated with either RU486 or GR siRNA appeared to be higher than those detected in controls. These results demonstrate that the blockage of effects mediated by the GCs normally found in fetal bovine serum might postpone senescence of these cells by up-regulating their antioxidant levels. Our data suggest that the blocking of the effects mediated by GCs might extend the lifespan of endogenous MSCs in patients who have elevated GC levels as a consequence of advancing age or estrogen depletion.     

Adenovirus-mediated BMP2 expression in human bone marrow stromal cells

Recombinant adenoviral vectors have been shown to be potential new tools for a variety of musculoskeletal defects. Much emphasis in the field of orthopedic research has been placed on developing systems for the production of bone. This study aims to determine the necessary conditions for sustained production of high levels of active bone morphogenetic protein 2 (BMP2) using a recombinant adenovirus type 5 (Ad5BMP2) capable of eliciting BMP2 synthesis upon infection and to evaluate the consequences for osteoprogenitor cells. The results indicate that high levels (144 ng/ml) of BMP2 can be produced in non-osteoprogenitor cells (A549 cell line) by this method and the resultant protein appears to be three times more biologically active than the recombinant protein. Surprisingly, similar levels of BMP2 expression could not be achieved after transduction with Ad5BMP2 of either human bone marrow stromal cells or the mouse bone marrow stromal cell line W20-17. However, human bone marrow stromal cells cultured with 1 microM dexamethasone for four days, or further stimulated to become osteoblast-like cells with 50 microg/ml ascorbic acid, produced high levels of BMP2 upon Ad5BMP2 infection as compared to the undifferentiated cells. The increased production of BMP2 in adenovirus transduced cells following exposure to 1 microM dexamethasone was reduced if the cells were not given 50 microg/ml ascorbic acid. When bone marrow stromal cells were allowed to become confluent in culture prior to differentiation, BMP2 production in response to Ad5BMP2 infection was lost entirely. Furthermore, the increase in BMP2 synthesis seen during differentiation was greatly decreased when Ad5BMP2 was administered prior to dexamethasone treatment. In short, the efficiency of adenovirus mediated expression of BMP2 in bone marrow stromal cells appears to be dependent on the differentiation state of these cells.     

Receptor tyrosine kinase expression in human bone marrow stromal cells

Bone marrow stromal cells (BMSCs) are a heterogeneous population of cells derived from colony-forming units-fibroblastic (CFU-Fs). These cells reside in the bone marrow cavity and are capable of differentiating into several cell phenotypes including osteoblasts, chondroblasts, hematopoiesis-supporting stromal cells, and adipocytes. However, the factors that regulate the proliferation and differentiation of the BMSC population are for the most part unknown. Since many members of the receptor tyrosine kinase (RTK) family have been shown to participate in growth control of various mesenchymal cell populations, in this study we examined the expression and function of RTKs in the BMSC population. Degenerate oligonucleotides corresponding to two conserved catalytic domains of the RTK family and RT-PCR were used initially to determine which RTKs are expressed in the human BMSC (hBMSC) system. After subcloning the amplification product generated from mRNA of a multicolony-derived hBMSC strain, PDGF receptor (β), EGF receptor, FGF receptor 1, and Axl were identified by DNA sequencing of 26 bacterial colonies. Furthermore, PDGF and EGF were found to enhance BMSC growth in a dose-dependent manner and to induce tyrosine phosphorylation of intracellular molecules, including the PDGF and EGF receptors themselves, demonstrating the functionality of these receptors. On the other hand, bFGF was found to have little effect on proliferation or tyrosine phosphorylation. Since single colony-derived hBMSC strains are known to vary from one colony to another in colony habit (growth rate and colony structure) and the ability to form bone in vivo, the expression levels of these RTKs were determined in 18 hBMSC clonal strains by semiquantitative RT-PCR and were found to vary from one clonal strain to another. While not absolutely predictive of the osteogenic capacity of individual clonal strains, on average, relatively high levels of PDGF-receptor were found in bone-forming strains, while on average, nonbone-forming strains had relatively high levels of EGF-receptor. Taken together, these results indicate that RTKs play a role in the control of hBMSC proliferation, and that the differential pattern of RTK expression may be useful in correlating the biochemical properties of individual clonal strains with their ability to produce bone in vivo. J. Cell. Physiol. 177:426–438, 1998. © 1998 Wiley-Liss, Inc.     

Density of human bone marrow stromal cells regulates commitment to vascular lineages

Mechanisms underlying the vascular differentiation of human bone marrow stromal cells (HBMSCs) and their contribution to neovascularisation are poorly understood. We report the essential role of cell density-induced signals in directing HBMSCs along endothelial or smooth muscle lineages. Plating HBMSCs at high density rapidly induced Notch signaling, which initiated HBMSC commitment to a vascular progenitor cell population expressing markers for both vascular lineages. Notch also induced VEGF-A, which inhibited vascular smooth muscle commitment while consolidating differentiation to endothelial cells with cobblestone morphology and characteristic endothelial markers and functions. These mechanisms can be exploited therapeutically to regulate HBMSCs during neovascularisation.