间充质干细胞的细胞表型及免疫学研究进展

间充质干细胞具有多分化潜能,参与构成骨髓的微环境,分泌大量细胞因子支持造血。最近的研究显示间充质干细胞免疫表型呈现动态的表达;同种异体细胞移植免疫排斥由于移植抗原差异而引起,但同种异体间充质干细胞却具有免疫抑制作用。综述了其可能的机制及作为组织工程种子细胞的间充质干细胞具有独特的生物学特性。     

骨髓异常增生综合征患者骨髓来源的间充质干细胞免疫功能异常

目的 研究骨髓异常增生综合征(myelodysplastic syndromes,MDS)难治性贫血(refractory anemia,RA)型患者(MDS-RA)和健康成年人骨髓来源的间充质干细胞(bone marrow derived mesenchymal stem cell,BMSC)的免疫学特征,比较它们是否存在免疫功能的异常.方法 分离MDS-RA和健康成年人来源的间充质干细胞,分别检测它们对T细胞周期、活化、抑制和增殖的作用情况.结果 MDS-RA的BMSC抑制T细胞增殖和活化能力均减弱,但是抑制活化的T细胞凋亡的作用反而增强.结论 MDS-RA患者骨髓来源的MSC存在明显的免疫调节功能缺陷,MDS-RA患者骨髓微环境可能存在免疫异常,如果使用MDS患者自体的MSC移植治疗可能不是一种很好的选择.对于MDS患者最好是选用异基因的MSC移植.     

大鼠骨髓间质干细胞对同种骨髓移植后造血重建和免疫重建的作用

目的：探讨大鼠骨髓间质干细胞（MSC）对 同种异体骨髓移植造血重建和免疫重建的影响。方法:建立大鼠同种异 体骨髓移植模型，通过生存率分析、外周血象检测、免疫细胞计数和受体免疫功能检测，综 合评价MSC对骨髓移植(bone marrow transplantation,BMT)后造血重建和免疫重建的作用。 结果：(1) MSC可促进BMT后造血重建：移植后30 d，共移植组外周血白 细胞、淋巴细胞和血小板数均高于单纯骨髓移植组；共移植组骨髓细胞数也高于对照组。(2 )MSC可促进BMT后免疫重建：移植后30 d，共移植组胸腺细胞数、脾细胞总数均高于骨髓单 纯移植组；共移植组对ConA、LPS 刺激的淋巴细胞增殖反应以及对第三体来源的同种混合淋 巴细胞反应均强于单纯BMT组。结论：大鼠MSC与骨髓共移植对同种异体 骨髓移植造血重建和免疫重建有一定促进作用。     

同种异体骨髓间充质干细胞的研究现状

背景：自体骨髓间充质干细胞移植是近年来在治疗关节软骨缺损较新的方法,但在临床上,急性骨软骨缺损很难在短时间内应用自体骨髓间充质干细胞修复,而同种异体的骨髓间充质干细胞可以提前制备,以备应用。 目的：系统分析同种异体骨髓间充质干细胞的免疫调节及抑制研究。 方法：以“Bone Mesenchymal Stem Cells,immunomodulation activity,immunosuppression;同种异体骨髓基质干细胞,免疫调节活性,免疫抑制”为关键词,由第一作者检索1990/2009 PubMed及万方数据库有关同种异体骨髓间充质干细胞免疫调节及抑制研究方面的文献。 结果与结论：虽然移植同种异体细胞有可能被受体体内的免疫系统攻击,但骨髓间充质干细胞是例外,因为它是免疫调节细胞,具有抑制免疫反应的作用。骨髓间充质干细胞对T细胞、B细胞、自然杀伤细胞和抗原提呈细胞均具有抑制作用。骨髓间充质干细胞是从骨髓中分离出来的组织工程细胞群,它携有免疫抑制相关标志,并在体外抑制同种异体T细胞增殖,因此骨髓间充质干细胞可用于同种异体细胞治疗。骨髓间充质干细胞为临床上同种异体骨髓间充质干细胞修复于关节软骨缺损提供了一种崭新的方法。     

血管内皮生长因子基因转染骨髓间充质干细胞同种异体移植治疗大鼠急性心肌梗死

目的探讨同种异体血管内皮生长因子(VEGF)基因转染的骨髓间充质干细胞(MSCs)在大鼠梗死心脏局部存活、分化及对心功能的影响;明确同种异体干细胞及VEGF基因转染干细胞移植治疗急性心肌梗死(AMI)的可行性及效果。方法雄性SD大鼠30只,随机分为单纯注射培养基对照组、MSCs治疗组及VEGF基因转染MSCs治疗组。分离纯化雄性Wistar大鼠骨髓间充质干细胞(rMSCs),于左冠状动脉前降支结扎1h后植入到SD大鼠心组织,移植4周后检测心功能并取心脏行组织染色检查。结果异体大鼠MSCs可在梗死心组织定居、生存;免疫组化检测MSCs转化为心肌细胞及血管内皮细胞;与对照组比较VEGF基因转染异体细胞移植组左室射血分数升高(P<0.05),梗死边缘区心肌面毛细血管数目明显增加(P<0.05)。结论同种异体VEGF基因转染MSCs移植治疗AMI可行、有效。     

慢性粒细胞白血病肿瘤干细胞的免疫调节功能

目的 研究慢性粒细胞白血病(CML)骨髓来源的肿瘤干细胞的免疫学特征,比较其与正常人来源的间充质干细胞(MSC)是否存在免疫功能的异常.方法 分离正常人和CML患者骨髓中的MSC,MLR法检测其对T细胞增殖的影响,流式细胞术检测其对T细胞周期、凋亡的作用情况.结果 CML和正常志愿者骨髓来源的MSC的细胞形态和表型没有差异,CML患者来源的MSC抑制T细胞增殖能力和抑制T细胞停留在G0/G1期的作用均减弱(CML MSC组74.5%±1.2%,BMSC组94.0%±1.9%,P＜0.05),CML患者抑制T细胞凋亡的作用增强(CMLMSC组8.36%±1.31%,BMSC组14.10%±0.65%,P＜0.05).结论 CML患者骨髓来源的MSC存在明显的免疫调节功能缺陷,如果使用CML患者自体的MSC移植治疗可能不是一种很好的选择,对于CML患者最好是选用异基因的MSC移植.     

富血小板血浆诱导骨髓间充质干细胞结合化学萃取去细胞神经修复坐骨神经缺损

背景:周围神经损伤早期许旺细胞尚未大量分裂增殖,此时由于解剖连续性的中断,通过轴浆逆向运输提供的营养因子骤减,缺乏神经营养因子支持的神经元有可能死亡,从而使周围神经不能再生或再生乏力。目的:观察植入经富血小板血浆诱导的骨髓间充质干细胞结合去细胞神经修复坐骨神经缺损的效果。方法:取新西兰大耳白兔制备坐骨神经缺损模型,随机抽签法分成4组:去细胞神经组,移植同种异体去细胞神经;骨髓间充质干细胞组,移植同种异体骨髓间充质干细胞结合化学萃取的同种异体去细胞神经:经诱导骨髓间充质干细胞组,移植经富血小板血浆诱导的同种异体骨髓间充质干细胞结合化学萃取的同种异体去细胞神经;自体神经组,移植自体神经。术后进行形态学观察与靶肌肉肌湿质量恢复率、运动神经传导速度、轴突直径和髓鞘厚度的检测。结果与结论:经富血小板血浆诱导的骨髓间充质干细胞结合化学萃取的去细胞神经移植修复神经的靶肌肉肌湿质量恢复率、运动神经传导速度、轴突直径和髓鞘厚度及形态学观察明显优于移植单纯化学萃取的去细胞神经与骨髓间充质干细胞结合化学萃取的去细胞神经的效果,而与移植自体神经修复结果相似。说明经诱导后的骨髓间充质干细胞在体内具有许旺细胞的部分功能,可作为组织工程化外周神经的种子细胞,用于周围神经缺损的修复。     

静脉移植CXCR-4基因转染骨髓间充质干细胞在脊髓损伤鼠体内的迁移与分化

背景：研究发现,基质细胞衍生因子1/CXCR-4轴具有介导骨髓间充质干细胞定向迁移的作用。 目的：观察静脉移植CXCR-4基因转染间充质干细胞治疗脊髓损伤的可行性。 方法：利用脊髓横切法构建C57BL/6小鼠T10脊髓损伤模型,造模后7 d抽签随机分成3组：实验组经尾静脉注射CXCR-4基因转染同种异体骨髓间充质干细胞悬液,对照组与空白对照组分别注射同种异体骨髓间充质干细胞悬液及无细胞培养基。移植后第7,14,21,28天利用激光共聚焦显微镜、免疫组织化学双标染色法检测脊髓损伤部位绿色荧光蛋白阳性细胞迁移存活及分化情况,并采用BBB评分评估小鼠神经运动功能恢复情况。 结果与结论：实验组移植后各时相点损伤灶内绿色荧光蛋白阳性细胞集聚明显,数量不断增多,迁移率明显高于对照组与空白对照组,来源于骨髓间充质干细胞的神经细胞占移植细胞的比例亦高于对照组与空白对照组,小鼠神经运动功能恢复明显。说明静脉移植CXCR-4基因转染的骨髓间充质干细胞表现出对脊髓损伤灶更强的定向迁移能力,且能在损伤灶内存活、分化,发挥修复损伤脊髓作用。     

人脐带源间充质干细胞体内外移植的免疫学特征

背景：部分体外实验证实人脐带源间充质干细胞具有同种异体的免疫耐受特性,然而对其体内研究尚处于异种异体之间,且结果及机制缺少统一性。 目的：培养人脐带源间充质干细胞,通过体内外试验分析其移植免疫学特性。 方法：应用组织块贴壁法提取人脐带源间充质干细胞,通过体外淋巴细胞混合反应检测其同种异体免疫耐受作用;应用流式细胞仪检测体内行人脐带源间充质干细胞移植前后患者血液中CD4、CD8浓度及比值变化,并通过ELISA方法对比体外淋巴细胞混合培养前后血液、培养上清及体内移植前后患者血液中白细胞介素2,10、γ-干扰素的浓度变化。 结果与结论：体内外实验中,混合淋巴细胞反应前后血浆及细胞上清中的细胞因子浓度变化呈相似趋势：白细胞介素10较反应前上升(P < 0.05),γ-干扰素较反应前下降(P < 0.05)。人脐带源间充质干细胞移植后患者T细胞亚群中CD4⁺/CD8⁺比值较移植前轻度下降。说明人脐带源间充质干细胞具有同种异体免疫耐受及免疫调节作用。     

组织工程化软骨细胞和骨髓间充质干细胞用于修复同种异体关节软骨缺损

背景：关节软骨几乎没有自身修复的能力,目前临床大多采用自体或异体软骨移植修复、软骨膜或骨膜移植修复、软骨细胞移植修复。由于自体软骨来源有限,异体软骨又存在慢性免疫排斥反应,最终可能导致预后不佳;软骨膜或骨膜移植修复的软骨易于退化,导致修复效果不佳。 目的：总结组织工程化软骨细胞、骨髓间充质干细胞及两者共培养对同种异体软骨缺损修复作用的研究现状。 方法：应用计算机检索PubMed 数据库及中国期刊网全文数据库1994-01/2012-01有关组织工程化软骨细胞和骨髓间充质干细胞用于修复同种异体关节软骨缺损方面的文章,英文检索词为“cartilage defect,allograft,chondrocyte,mesenchymal stem cells,bone marrow mesenchymal stem cells”,中文检索词为“软骨缺损,同种异体移植,软骨细胞,骨髓间充质干细胞”。排除重复性及非中英文语种研究,共保留35篇文献进行综述。 结果与结论：随着体外细胞培养方法的不断改进,现已能够把软骨细胞从坚韧的软骨中分离出来,并获得大量高纯度的软骨细胞并繁殖出新生软骨细胞。软骨细胞培养增殖能力低,传代培养容易引起老化和去分化;而成体骨髓中骨髓间充质干细胞含量少,随传代次数的增多成软骨潜能明显降低。骨髓间充质干细胞和软骨细胞共培养,两种细胞相互促进增殖和分化,作为种子细胞可减少软骨细胞增殖传代次数并节省软骨细胞数量,与组织工程支架材料复合能有效修复关节软骨缺损。     

Comparison of immunological properties of bone marrow stromal cells and adipose tissue-derived stem cells before and after osteogenic differentiation in vitro

Mesenchymal stem cells (MSCs) can be isolated from various tissues and represent an attractive cell population for tissue-engineering purposes. MSCs from bone marrow (bone marrow stromal cells [BMSCs]) are negative for immunologically relevant surface markers and inhibit proliferation of allogenic T cells in vitro. Therefore, BMSCs are said to be available for allogenic cell therapy. Although the immunological characteristics of BMSCs have been the subject of various investigations, those of stem cells isolated from adipose tissue (ASCs) have not been adequately described. In addition, the influence of osteogenic differentiation in vitro on the immunological characteristics of BMSCs and ASCs is the subject of this article. Before and after osteogenic induction, the influence of BMSCs and ASCs on the proliferative behavior of resting and activated allogenic peripheral blood mononuclear cells (PBMCs) was studied as a measure of the immune response (mixed lymphocyte culture). At the same points, the expression of immunologically relevant surface markers (e.g., major histocompatibility complex (MHC)-I, MHC-II, CD40, CD40L) was measured, and correlations between the different sets of results were sought. The pattern of surface antigen expression of BMSCs is the same as that of ASCs. Analogous to BMSCs, undifferentiated cells isolated from adipose tissue lack expression of MHC-II; this is not lost in the course of the osteogenic differentiation process. In co-culture with allogenic PBMCs, both cell types fail to lead to any significant stimulation, and they both retain these characteristics during the differentiation process. BMSCs and ASCs suppress proliferation on activated PBMCs before and after osteogenic differentiation. Our results confirm that MSCs are immune modulating cells. These properties are retained even after osteogenic induction in vitro and seem to be similar in BMSCs and ASCs. Our results suggest that allogenic transplantation of BMSCs and ASCs would be possible, for example, in the context of tissue engineering.     

同种异体骨髓间充质干细胞移植上调急性心肌梗死大鼠Cx43的表达

目的研究同种异体骨髓间充质干细胞(MSCs)移植心肌梗死(MI)大鼠后缝隙连接蛋白43(Cx43)在不同时期的动态变化。方法建立大鼠MI模型。将同种异体MSCs用5-氮胞苷诱导成心肌样细胞并行荧光标记,经二次开胸注射入MI大鼠梗死区和梗死边缘区。各亚组分别于移植后4、8和12周在荧光显微镜下跟踪MSCs移植情况。同时用免疫组化分析Cx43表达与缝隙连接(GJ)分布。结果MSCs体外诱导可分化为自发搏动的心肌样细胞,表达心肌特异性肌钙蛋白T(cTnT)和形成肌丝结构。MSCs移植后可长期存活并在4、8和12周,并有效上调缺血区Cx43的表达,改善GJ分布紊乱状态。在梗死区Cx43无特殊改变。结论MSCs具有分化为心肌样细胞的可塑性,移植后上调MI后缺血区Cx43表达,改善GJ分布紊乱。     

Bone marrow mesenchymal stem cells overexpressing human basic fibroblast growth factor increase vasculogenesis in ischemic rats

Administration or expression of growth factors, as well as implantation of autologous bone marrow cells, promote in vivo angiogenesis. This study investigated the angiogenic potential of combining both approaches through the allogenic transplantation of bone marrow-derived mesenchymal stem cells (MSCs) expressing human basic fibroblast growth factor (hbFGF). After establishing a hind limb ischemia model in Sprague Dawley rats, the animals were randomly divided into four treatment groups: MSCs expressing green fluorescent protein (GFP-MSC), MSCs expressing hbFGF (hbFGF-MSC), MSC controls, and phosphate-buffered saline (PBS) controls. After 2 weeks, MSC survival and differentiation, hbFGF and vascular endothelial growth factor (VEGF) expression, and microvessel density of ischemic muscles were determined. Stable hbFGF expression was observed in the hbFGF-MSC group after 2 weeks. More hbFGF-MSCs than GFP-MSCs survived and differentiated into vascular endothelial cells (P<0.001); however, their differentiation rates were similar. Moreover, allogenic transplantation of hbFGF-MSCs increased VEGF expression (P=0.008) and microvessel density (P<0.001). Transplantation of hbFGF-expressing MSCs promoted angiogenesis in an in vivo hind limb ischemia model by increasing the survival of transplanted cells that subsequently differentiated into vascular endothelial cells. This study showed the therapeutic potential of combining cell-based therapy with gene therapy to treat ischemic disease.     

Mouse bone marrow-derived mesenchymal stem cells acquire immunogenicity concurrent with differentiation to insulin-producing cells

BackgroundAlthough mesenchymal stem cells (MSCs) are regarded as immune-elusive and even immunosuppressive, recent evidence suggests that allogeneic immune response might is inevitable in the case of some lineages differentiated from MSCs. Regarding the importance of allogeneic IPCs and MSCs in pre-clinical and clinical studies, the present study aimed to investigate the possible changes in the immunogenicity of MSCs during the differentiation to IPCs in a murine model of allogeneic transplantation.Material and methodsTwo mouse strains, C57BL/6 (H2D^b) and BALB/c (H2D^d) were selected to establish an allogeneic cell transplantation model. Bone marrow MSCs were differentiated into IPCs and the expression of H2D, CD80, and Qa-2 molecules were evaluated via flowcytometry on MSCs and IPCs. The differentiated and undifferentiated MSCs were encountered to allogeneic splenocytes and the proliferation, CD44 activation marker, and cytokine release in the splenocytes were evaluated.ResultsIPCs exhibited increased expression of MHC-I and CD80 that elicited an allogenic response including the activation-induced proliferation of splenocytes, activation of CD4⁺ T cells, and IFNγ response.ConclusionsMSCs acquire immunogenicity after differentiation to functional IPCs, which might cause decreased efficacy in the case of allogeneic transplantation. Careful precautions might be critical for saving the IPCs against the detrimental allogeneic responses.     

Effects of valproic acid on the expression of trophic factors in human bone marrow mesenchymal stromal cells

The potential of human bone marrow-mesenchymal stromal cells (hBM-MSCs) to differentiate into diverse cell types and secrete a variety of trophic factors makes them an excellent cell therapy tool for intractable diseases. However, their therapeutic efficacy has not yet been satisfied in preclinical and/or clinical trials with autologous or allogenic stem cells. To improve the efficacy of stem cell therapy, optimized conditions for stem cells need to be defined. In this study, we evaluated the effects of valproic acid (VPA), an HDAC inhibitor, in human BM-MSCs and assessed the expression of trophic factors (ANG, BDNF, ECGF1, bFGF-2, GDNF, HGF, IGF-1, PIGF, TGF-β1, and β-Pix) in MSCs treated with 200μg/ml VPA for 12h. Under these conditions the features of MSCs were not changed. The VPA-treated MSCs also showed an increased cell protective effect against oxidative injuries in MTT assays and improved migratory ability when examined by the Boyden chamber assay. This suggests that MSCs may be improved by treatment with an optimal VPA dose and incubation time, which may increase the efficacy of stem cell therapy.     

Co-culture of umbilical cord blood CD34+ cells with human mesenchymal stem cells

Insufficient numbers of hematopoietic stem cells (HSCs) and hematopoietic progenitor cells (HPCs) sometimes limit allogenic transplantation of umbilical cord blood (UCB). Ex vivo expansion may overcome this limitation. Mesenchymal stem cells (MSCs), as non-hematopoietic, well-characterized skeletal and connective-tissue progenitor cells within the bone marrow stroma, have been investigated as support cells for the culture of HSCs/HPCs. MSCs are attractive for the rich environmental signals that they provide and for immunological compatibility in transplantation. Thus far, HSC/MSC co-cultures have mainly been performed in 2-dimensional (2D) configuration. We postulate that a 3-dimensional (3D) culture environment that resembles the natural in vivo hematopoietic compartment might be more conducive for regulating HSC expansion. In this study, we compared the co-culture of HSCs and MSCs in 2D and 3D configurations. The results demonstrated the benefit of MSC inclusion in HSC expansion ex vivo. Direct contact between MSCs and HSCs in 3D cultures led to statistically significantly higher expansion of cord blood CD34+ cells than in 2D cultures (891- versus 545-fold increase in total cells, 96- versus 48-fold increase of CD34+ cells, and 230- versus 150-fold increase in colony-forming cell assay [CFC]). Engraftment assays in non-obese diabetic/severe combined immunodeficiency mice also indicated a high success rate of hematopoiesis reconstruction with these expanded cells.     

Mesenchymal stem cells from periapical lesions modulate differentiation and functional properties of monocyte‐derived dendritic cells

Immunoregulatory mechanisms within periapical lesions (PLs) are as of yet unexplored. Considering the crucial role of DCs in controlling the immune response within PLs, the immunomodulatory properties of mesenchymal stem cells (MSCs), and the colocalization of MSCs and DCs in situ, we wondered whether MSCs from PLs modulate the development and functions of DCs. Using a model of monocyte‐derived DCs, we showed that PL‐MSCs inhibited differentiation of DCs via soluble factors, of which IL‐6 had a minor effect, but did not impair their subsequent maturation induced by pro‐inflammatory cytokines. However, upon maturation such DCs favored the production of Th2/Th17 cytokines by allogenic CD4⁺ lymphocytes in coculture, compared with mature DCs differentiated without PL‐MSCs. PL‐MSC‐differentiated DCs, cultivated with pro‐inflammatory cytokines and PL‐MSCs, although phenotypically mature, exhibited poor allostimulatory activity, induced anergy, Th2 polarization, differentiation of suppressive CD4⁺CD25^highCD39⁺ Treg‐cell subsets via IDO‐1‐, ILT‐3‐, and ILT‐4‐dependent mechanisms, and increased production of TGF‐β in the coculture. In contrast, DCs cultivated with PL‐MSCs only during maturation stimulated proliferation and Th1 polarization of CD4⁺ T cells in an IL‐12‐independent manner. In conclusion, PL‐MSCs significantly modulate the development and functions of DCs, depending on the phase of DCs development during which the interaction occurs.     

Regulation of proliferation and chondrogenic differentiation of human mesenchymal stem cells by laminin-5 (laminin-332)

Laminin-5 (laminin-332) is an important basement membrane protein that regulates cell attachment and motility. Recent studies have shown that laminin-5 is expressed in human mesenchymal stem cells (MSCs) in culture and that the laminin gamma2 chain is transiently expressed in chondrocytes during development. These studies suggest that laminin-5 may be involved in the regulation of chondrogenic differentiation of MSCs. In this study, we examined a possible role of laminin-5 in the proliferation and differentiation of human MSCs. When MSCs were incubated in the presence of a coated or soluble form of laminin-5 in a growth medium, they proliferated more rapidly than nontreated cells, keeping their differentiation potential. On the other hand, laminin-5 potently suppressed the chondrogenic differentiation of MSCs. These activities were mediated mainly by integrin alpha3beta1. However, laminin-5 had no effect on the osteogenic differentiation of MSCs. These results suggest that laminin-5 may contribute to the development of bone tissues by promoting the proliferation and by suppressing the chondrogenic differentiation of MSCs.     

Concise review: adult multipotent stromal cells and cancer: risk or benefit?

This review focuses on the interaction between multipotent stromal cells (MSCs) and carcinoma and the possible use of MSCs in cell-based anticancer therapies. MSCs are present in multiple tissues and are defined as cells displaying the ability to differentiate in multiple lineages, including chondrocytes, osteoblasts, and adipocytes. Recent evidence also suggests that they could play a role in the progression of carcinogenesis and that MSCs could migrate toward primary tumors and metastatic sites. It is possible that MSCs could also be involved in the early stages of carcinogenesis through spontaneous transformation. In addition, it is thought that MSCs can modulate tumor growth and metastasis, although this issue remains controversial and not well understood. The immunosuppressive properties and proangiogenic properties of MSCs account, at least in part, for their effects on cancer development. On the other hand, cancer cells also have the ability to enhance MSC migration. This complex dialog between MSCs and cancer cells is certainly critical for the outcome of tumor development. Interestingly, several studies have shown that MSCs engineered to express antitumor factors could be an innovative choice as a cell-mediated gene therapy to counteract tumor growth. More evidence will be needed to understand how MSCs positively or negatively modulate carcinogenesis and to evaluate the safety of MSC use in cell-mediated gene strategies. Disclosure of potential conflicts of interest is found at the end of this article.