The aging effect of chemotherapy on cultured human mesenchymal stem cells

Various agents, including chemotherapeutic drugs, can induce cell senescence. However, the mechanisms involved in the aging pathway, particularly the stress that chemotherapy imposes on telomeres, are still undefined. To address these issues, human mesenchymal stem cells (MSCs) were assessed as target cells to investigate the initiation of the aging process by chemotherapy. The MSCs were obtained from bone marrow (BM) cells from normal adults and grown in the presence of platelet lysates. Cultured MSCs were identified for immunophenotype, and for growth and differentiation properties. The MSCs were exposed to 10 nM doxorubicin and 500 ng/mL etoposide, sublethal doses that induce DNA double-stranded breaks. Telomere length (TL) was assessed by flow-fluorescence in situ hybridization and Southern blotting. Initial TL shortening was detectable in MSCs at 5 days after drug exposure, with progressive reduction compared with untreated cells at 7, 14, 21, and 28 days in culture. After a single exposure, MSCs were unable to regain the lost telomere sequences for up to 28 days in culture. The ATM phosphorylation was documented early after drug exposure, while no telomerase activation was observed. Chemotherapy-induced TL shortening was associated with reduced clonogenic activity in?vitro and accelerated adipose differentiation. Analogous behavior in the differentiation pattern was observed in naturally aged MSCs. These results indicate that cultured MSCs represent a useful cellular model to investigate novel drugs that may favor or, conversely, might prevent TL loss in human stem cells. The TL shortening is a permanent signature of previous chemotherapy-mediated DNA?damage, and predicts impaired proliferative and differentiation potential.     

骨髓间充质干细胞的培养及低氧条件对其影响

目的 骨髓间充质干细胞(BMMSC)的体外培养和低氧对于BMMSC增殖作用的影响.方法 成年雄性SD大鼠断颈处死后于75％酒精中浸泡5 min.用全骨髓贴壁法培养细胞,选取生长状态良好的第3代细胞进行鉴定.以单克隆抗体CD45、CD90行流式细胞术鉴定大鼠BMMSC.用四甲基偶氮唑蓝(MTT)法测定第3代BMMSC以及低氧处理的第3代BMMSC的增殖情况.结果 用全骨髓贴壁法分离并培养SD大鼠BMMSC;流式细胞仪检测显示:第3代BMMSC表面特异性标志CD90表达率为96.0％,而非BMMSC表面标志CD45仅为2.5％.MTT结果显示低氧条件下的BMMSC比常氧条件下增殖速率高,并且光镜下观察到细胞状态均一,折光性更好.结论 用全骨髓贴壁法可以在体外分离、培养出纯度较高的SD大鼠来源BMMSC,低氧环境可以刺激BMMSC的增殖.     

In vitro hepatic differentiation of human mesenchymal stem cells

This study examined whether mesenchymal stem cells (MSCs), which are stem cells originated from embryonic mesoderm, are able to differentiate into functional hepatocyte-like cells in vitro. MSCs were isolated from human bone marrow and umbilical cord blood, and the surface phenotype and the mesodermal multilineage differentiation potentials of these cells were characterized and tested. To effectively induce hepatic differentiation, we designed a novel 2-step protocol with the use of hepatocyte growth factor and oncostatin M. After 4 weeks of induction, cuboidal morphology, which is characteristic of hepatocytes, was observed, and cells also expressed marker genes specific of liver cells in a time-dependent manner. Differentiated cells further demonstrated in vitro functions characteristic of liver cells, including albumin production, glycogen storage, urea secretion, uptake of low-density lipoprotein, and phenobarbital-inducible cytochrome P450 activity. In conclusion, human MSCs from different sources are able to differentiate into functional hepatocyte-like cells and, hence, may serve as a cell source for tissue engineering and cell therapy of hepatic tissues. Furthermore, the broad differentiation potential of MSCs indicates that a revision of the definition may be required.     

人骨髓间充质干细胞体外分化为肝细胞样细胞

目的 探讨人骨髓间充质干细胞(MSCs)的体外培养及特异性诱导为肝细胞样细胞的能力。方法 骨髓标本来源于健康志愿者的胸骨,年龄2～35岁,采用淋巴细胞分离液(密度1.077)分离人MSCs,并分别采用HGF、FGF4、HGF FGF4以及无生长因子四种处理因素体外诱导第三代人MSC向肝细胞样细胞分化。通过流式细胞术分析鉴定.MSCs的纯度,于诱导培养的0、7、14、21、28天时留取细胞检测CK18、AFP和白蛋白的表达情况,同时进行糖原染色验证细胞功能。结果 用淋巴细胞分离液分离出的人MSCs纯度可达90％,采用HGF、FGF4及HGF FGF4三种处理因素均可在体外诱导人MSCs特异分化为具有肝细胞样细胞表型和功能的细胞。结论 人MSCs能在体外扩增并定向诱导为肝细胞样细胞。     

5-氮胞苷体外诱导骨髓间充质干细胞向心肌样细胞的分化

目的: 研究5-氮胞苷（5-Aza）对培养人骨髓间充质干细胞（MSC）的作用,并对分化后的心肌样细胞进行鉴定。方法: 采用密度梯度离心法分离到骨髓单个核细胞（MB-MNC）,用含200 ml/L胎牛血清的低糖型DMEM培养液进行培养。采用差速贴壁法纯化MSC,用流式细胞仪检测细胞表面抗原。以5-Aza诱导第3代MSC 24 h后继续培养。培养4周,用免疫细胞化学染色法检测肌系标记抗原:α-肌动蛋白（α-actin）及心肌细胞特异性标记抗原:肌钙蛋白T（cTnT）;在透射电镜下观察细胞的超微结构。结果: MSC经5-Aza诱导分化后,可表达α-actin和cTnT,未经诱导的同培养天数的MSC中均未见表达。透射电镜可观察到肌丝等心肌细胞的特异性结构。结论: 5-Aza可诱导MSC分化为心肌样细胞。     

米托坦逆转P-gP介导的人卵巢癌细胞的耐药作用及机制探讨

目的探讨米托坦对人卵巢癌细胞耐药的逆转作用及机制。方法采用10．0μM的阿霉素（ADM）体外高浓度反复间歇诱导法建立人卵巢癌细胞OVCAR-3／ADM耐药模型,观察其对紫杉醇、米托蒽醌、长春新碱、丝裂霉素、顺铂的耐药情况;MTT法检测不同浓度米托坦以及不同浓度米托坦联合ADM对OVCAR-3／ADM的生长抑制作用;Westernblot法检测OVCAR-3／ADM的P-gp蛋白表达情况。结果OVCAR-3的IC50为10．0μM;OVCAR．3／ADM的IC50为164．65μM,耐药指数为16．3。OVCAR-3／ADM对上述六种化疗药均产生了耐药性。10．0μM的ADM对OVCAR-3／ADM细胞的生长抑制率为4．78％。米托坦在高浓度时（≥30．0μM）时才表现出强的抑制肿瘤细胞生长作用,而米托坦与ADM联合应用时在米托坦浓度大于1μM时便可呈剂量依赖性抑制肿瘤细胞的生长,且抑制率明显高于单纯应用米托坦组及ADM组,100．0μM米托坦＋10．0斗MADM组细胞生长抑制率最高,达到50．24％,与ADM组比较,经米托坦处理过的OVCAR-3／ADM的P-gp蛋白表达下降。结论OVCAR-3／ADM为获得性多药耐药细胞系,米托坦可增强该细胞系对ADM的敏感性,其逆转耐药的机制可能与下调OVCAR-3／ADM的P-gp蛋白表达有关。     

Adipogenic effect of alcohol on human bone marrow-derived mesenchymal stem cells

BACKGROUND: In addition to a decrease in bone mass in alcoholics their osteopenic skeletons show an increase in bone marrow adiposity. Human bone marrow mesenchymal stem cells (hMSC) in vivo differentiate into several phenotypes including osteogenic and adipogenic cells, both of which remain as resident populations of bone marrow. In vitro, the lineage commitment and differentiation of hMSC toward the adipogenic pathway can be promoted by alcohol. METHODS: Human male and female mesenchymal stem cells from joint replacement surgery were cultured. Cells were grouped as: 1) Control (no additions to the culture medium), 2) EtOH (50 mm alcohol added to the culture medium), 3) OS (osteogenic inducers added to the culture medium), and 4) OS + EtOH (osteogenic inducers and 50 mm alcohol added to the culture medium). Cultures stained with Nile Red confirmed the development of differentiated adipocytes. Population analysis was performed using fluorescence-activated cell sorting. Gene expression of early, middle, late, and terminal differentiation stage markers (PPAR)gamma2, lipoprotein lipase, adipsin, leptin, and adipocyte P2 (aP2)] was studied by Northern hybridization, and protein synthesis of aP2 was determined by Western analysis. RESULTS: Nile red staining confirmed increased adipocyte development 10 days after the onset of treatment with 50 mm alcohol and osteogenic induction. By day 21 the number of adipocytes increased to 13.6% of the total population. Alcohol up-regulated the gene expression of PPARgamma2 whereas no up-regulation was observed for the other genes. Protein production of aP2 was significantly increased in hMSC cells by culture in the presence of alcohol. CONCLUSIONS: The data suggest that alcohol's adipogenic effect on cultured hMSC is through up-regulation of PPARgamma2 at the point of lineage commitment as well as through enhancement of lipid transport and storage through increased aP2 synthesis. The alcohol-induced expression and synthesis changes account for the increased Nile red staining of cultured hMSC.     

体外诱导人羊膜间充质干细胞分化为胰岛素分泌细胞

目的 探讨体外诱导人羊膜间充质干细胞(hAD-MSCs)向胰岛素分泌细胞分化潜能.方法 采用胰蛋白酶-胶原酶消化法分离提取hAD-MSCs,流式细胞术分析和免疫细胞化学染色行表型鉴定.取第3代按2.5× 106个/ml或5×105个/ml细胞密度接种6孔培养板或预置盖玻片的24孔培养板,在含10mmol/L尼克酰胺和N2补充物的无血清HG-DMEM培养基培养,未诱导组为含10％胎牛血清的LG-DMEM基础培养基.分别于体外诱导第7、14、21天采用免疫细胞化学法检测胰岛素和β2微球蛋白的表达,采用放射免疫法检测上清液中胰岛素含量,采用RT-PCR检测胰岛素mRNA和胰十二指肠同源异型盒因子1(PDX-1)mRNA的表达.结果 (1)hAD-MSCs高表达间充质干细胞表面标志CD29、CD44、CD73、CD166及波形蛋白;(2) hAD-MSCs诱导第7、14、21天胰岛素阳性细胞百分率分别为74.67％±1.53％、75.00％±1.00％、74.33％±1.53％,培养物上清液中胰岛素含量分别为(331.62±1.76)、(330.50±1.22)和(331.65±0.48) μIU/ml,各时点间比较无显著性差异(均P＞0.05),而未诱导组仍未见胰岛素阳性细胞;培养上清也未检测到胰岛素;(3) hAD-MSCs诱导前后均有PDX-1 mRNA和蛋白表达,胰岛素基因mRNA表达仅见于诱导组;(4) hAD-MSCs诱导组和未诱导组各时点均有β2微球蛋白表达,其阳性细胞百分率组间差异无显著性(均P＞0.05).结论 hAD-MSCs具有向胰岛素分泌细胞分化的能力,可能成为1型糖尿病细胞移植治疗的新的细胞供源.     

体外诱导成人骨髓间充质干细胞转化为神经元细胞的实验研究

目的探讨成人骨髓间充质干细胞(hMSCs)在体外特定的诱导条件下,转化为神经元细胞的规律、效率及长期存活的条件.方法采用β-巯基乙醇为诱导剂,在体外诱导6 h后,改用诱导维持液使诱导后的细胞在诱导维持液中存活6 d.用细胞化学及免疫组织化学、Western blot方法检测神经元细胞、星形胶质细胞标记蛋白的表达.结果诱导6 h,诱导后的细胞尼氏染色胞浆中可见深蓝色的尼氏体形成;细胞表达NSE、NF-M,而不表达GFAP;NSE、NF-M阳性细胞数超过80%以上.Western blot结果显示:诱导6 h,诱导后的细胞表达Nestin,而无MAP-2的表达,随着时间的延长,Nestin的表达逐渐减少,而出现了MAP-2的表达.结论β-巯基乙醇在体外可定向诱导hMSCs经神经干细胞转化为神经元细胞,而且诱导后的神经元细胞逐渐趋于成熟.     

人脐带间充质干细胞体外培养过程中的表观遗传学改变

目的分离、培养人脐带间充质干细胞(hUC-MSCs),并探讨体外培养过程中表观遗传学的改变。方法随机选取足月顺产健康胎儿脐带,采取复合酶消化法从脐带胶质中获得hUC-MSCs。流式细胞术检测细胞表面标志物。分化培养基诱导hUC-MSCs分化。β-半乳糖苷酶染色检测细胞衰老。甲基化特异性PCR(MSP)检测hUC-MSCs在不同培养时期特定基因的甲基化状态。蛋白免疫印记(Western blot)检测hUC-MSCs在不同培养时期MGMT基因的蛋白表达。结果按整根脐带30 cm计算,可收获(3～6)×106hUC-MSCs。培养的hUC-MSCs高表达CD29、CD73、CD105、CD90和CD44,不表达CD45、CD34和HLA-DR。hUC-MSCs可定向分化为成脂、成骨和成软骨细胞。随着细胞的传代,衰老细胞占细胞总数的比例增加。培养后期的hUC-MSCs出现MGMT基因甲基化。结论复合酶消化法可从脐带胶质中获得具有间充质干细胞(MSC)特性的细胞。随着传代次数的增多,DNA修复基因MGMT出现甲基化,可能参与hUC-MSCs衰老调控。     

Progressive increase in conduction velocity across human mesenchymal stem cells is mediated by enhanced electrical coupling

OBJECTIVE: The purpose of the study was to investigate the development of electrical transmission across human adult bone marrow-derived mesenchymal stem cells (hMSCs) during long-term co-incubation with cardiomyocytes (CMCs). METHODS: Neonatal rat CMCs were cultured in multi-electrode array dishes. A conduction block was induced by creating a central acellular channel, yielding two asynchronously beating CMC fields. Enhanced green fluorescent protein (eGFP)-labeled hMSCs from ischemic heart disease patients (n=8), eGFP-labeled hMSCs having RNA interference-mediated connexin43 (Cx43) knockdown (n=6), 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine (Dil)-labeled CMCs (n=6), or no cells (n=9) were seeded in the channel. Assessment of conduction velocity (CV), Cx expression and localization, gap junctional coupling, and intracellular electrical recordings were performed for up to 14 days. RESULTS: Resynchronization of the two CMC fields occurred within 24 h after seeding of hMSCs. CV across hMSCs increased from 1.4+/-0.4 cm/s at day 7 to 3.5+/-0.1 cm/s (p<0.05) at day 14. CV across seeded CMCs was 16.8+/-0.2 cm/s throughout this period. No resynchronization occurred in the absence of seeded cells. Knockdown of Cx43 in hMSCs abolished conduction across the channel completely. Time-dependent increase of CV across hMSCs was associated with increased Cx43 mRNA and protein expression resulting in increased gap junctional coupling. Intracellular recordings in coupled hMSCs showed increased conducted action potential (AP) amplitude, lower resting membrane potential, and decreased duration of conducted AP (p<0.05, day 14 versus day 1). CONCLUSIONS: CV across hMSCs increases progressively after 7 days of co-incubation with CMCs, most likely via improved electrotonic interaction. This is associated with increased Cx43 expression, increased functional gap junctional coupling, and enhanced intercellular electrical coupling between hMSCs and CMCs.     

不同年龄人骨髓间充质干细胞体外培养增殖的研究

目的本研究分析不同年龄段人骨髓间充质干细胞的生长和增生情况,探讨年龄对于骨髓间充质干细胞的影响。方法采集61例不同年龄人的骨髓,分为少年组、中青年组和老年组,分离间充质干细胞,进行体外培养,观察其形态变化,对比分析其首次传代和每次传代时间、细胞克隆形成数量、细胞增长曲线的变化情况。结果体外培养的干细胞在形态上无年龄差异,均成梭形纤维状,早期呈克隆状生长。细胞的首次传代时间从少年到老年呈逐渐增加的趋势,老年组明显长于另外两组;3组的体外培养倍增时间无明显差异,但老年组的干细胞克隆数量减少（差异尚未达到统计学意义）,细胞的增殖显著低于另外两组（P<0.05）。结论人骨髓间充质干细胞的生长增殖能力随着增龄而逐渐减退,尤其在老年组呈现出更明显的变化。     

脐带间充质干细胞体外诱导分化为肝细胞样细胞的研究

目的探讨人脐带间充质干细胞（UC-MSCs）体外诱导分化为肝细胞的可行性和方法,观察分化后的细胞白细胞表面抗原表达的改变。方法采用酶学法从脐带全层组织中分离UC-MSCs,采用改良的肝分化培养体系体外诱导UC-MSCs向肝细胞分化。诱导后2、4周,观察细胞形态,免疫荧光细胞化学染色法检测甲胎蛋白（AFP）、白蛋白（ALB）;RT-PCR检测肝细胞标志性基因AFP、ALB和CK19 mRNA。ELISA法检测诱导后的细胞培养液中ALB水平。流式细胞仪检测诱导后细胞白细胞表面抗原HLA-Ⅰ和HLA-Ⅱ。结果从人脐带基质中分离培养的UC-MSCs在向肝细胞诱导分化培养体系的培养下,细胞形态由长梭形逐渐转化成为多角形或类圆形,并且表达AFP、ALB mRNA和蛋白,诱导后的UC-MSCs以时间依赖方式产生ALB,诱导后的细胞不表达HLA-DR。结论UC-MSCs具有向肝细胞分化的潜能,分化后的M细胞仍具有低免疫原性。     

两种成人骨髓间充质干细胞体外分离方法的比较研究

目的比较两种体外分离方法获得的成人骨髓间充质干细胞的形态、增殖能力和纯度。方法分别采用直接贴壁法和密度离心法分离成人骨髓间充质干细胞,观察细胞形态;采用MTT法绘制第3代细胞的生长曲线并计算对数期倍增时间;将1×105个第3代细胞连续培养扩增至第30天并计数细胞总数;采用流式细胞仪检测第3代细胞CD31、CD34、CD73、CD105和CD166等表型。结果两种方法获得的MMSCs均呈长梭状成纤维样细胞形态;直接贴壁法获得的细胞首次传代时间为10d,对数生长期倍增时间为30±5.6h,而密度离心法细胞首次传代时间为18d,对数生长期倍增时间为38±7.2h;连续培养至第30d时,直接贴壁法细胞总数约为密度离心法细胞的15倍;直接贴壁法第3代细胞表达CD73、CD105和CD166的阳性率均低于密度离心法（P〈0.05）。结论应用直接贴壁法和密度离心法均可有效分离成人骨髓间充质干细胞,直接贴壁法分离的细胞增殖能力更强,而密度离心法分离的细胞纯度更高。     

体外诱导骨髓间充质干细胞向神经元样细胞分化的研究

目的观察人骨髓间充质干细胞（BM-MSCs）体外扩增和定向诱导分化为神经元样细胞的变化,为其临床应用奠定基础。方法采用密度梯度离心法分离BM-MSCs细胞,用MesencultTM培养基和贴壁培养法培养、纯化和扩增细胞,流式细胞术检测细胞表面CD29和CD90分子表达率。采用20 ng/ml重组碱性成纤维细胞生长因子（bFGF）、20 ng/ml新型人表皮生长因子（hEGF）和20 g/L二甲基亚砜（DMSO）、5 mmol/Lβ-巯基乙醇（BME）分别诱导BM-MSCs;采用免疫组化法检测细胞的神经元特异性烯醇化酶（NSE）、胶原纤维酸性蛋白（GFAP）、波形蛋白（VIM）表达情况。结果BM-MSCs细胞增殖迅速,3周可传代培养;BM-MSCs传十代扩增1－2×10^3倍。分离和扩增BM-MSCs CD29、CD90强表达率分别为95.02%、93.81%。药物诱导后的BM-MSCs发生轴突等神经元样细胞变化,阳性表达NSE、GFAP、VIM分子。结论人BM-MSCs能体外培养和扩增,并能定向诱导分化为神经元样细胞。     

人脂肪间充质干细胞体外分离、培养的方法研究

目的：探讨人脂肪间充质干细胞体外分离及培养方法。方法用消化离心的方法获得人脂肪间充质干细胞,以1×104/cm2接种于体积分数为0．1％胎牛血清的LG-DMEM培养基中,并进行细胞形态学观察,绘制细胞生长曲线,流式细胞仪检测细胞表面抗原,行成脂及成骨诱导检测其多向分化潜能。结果获取的脂肪间充质干细胞大小较为均匀,呈梭形的成纤维细胞样,细胞增殖良好;细胞生长曲线测定表明接种后第4天细胞进入指数增长期,第8天后生长进入平台期,体外能长期培养存活,并保持不分化状态;流式细胞仪检测表明细胞高表达 CD13、CD73,低表达 CD34、CD45及 HLA-DR;能诱导成脂及成骨细胞。结论利用消化离心法在体外能分离得到脂肪间充质干细胞,细胞生长良好,可作为组织工程的种子细胞。