骨髓基质细胞对多细胞因子介导人脐血单个核细胞体外扩增的影响*

背景：体外扩增脐血造血细胞的目的是促进脐血造血细胞的植入能力,细胞因子介导的脐血造血细胞能使细胞数有效扩增,但同时也耗竭了具有分化潜能的造血干细胞。 目的：观察骨髓基质细胞对多细胞因子组合介导人脐血单个核细胞体外扩增及扩增后黏附分子和CXCR4表达的影响。 方法：将分离的人脐血单个核细胞接种在预先建立的人骨髓基质细胞层上,分组培养：对照组仅含有脐血单个核细胞;多种细胞因子+脐血单个核细胞组;骨髓基质细胞+脐血单个核细胞组;骨髓基质细胞+多种细胞因子+脐血单个核细胞组。培养0,7 d检测有核细胞数, CD34+细胞数及CD34+CXCR4+,CD34+CD62L+,CD34+CD49d+的细胞数。 结果与结论：单纯骨髓基质细胞和单用细胞因子组均可有效地扩增脐血造血细胞,并提高造血细胞上CD49d,CD62L及 CXCR4表达。而单用细胞因子组促进脐血造血细胞扩增能力较单纯骨髓基质细胞强,提高造血细胞CD49d,CD62L及 CXCR4表达能力较单纯骨髓基质细胞差。提示骨髓基质细胞虽可支持脐血造血细胞扩增,但难以实现造血细胞的大量扩增,但在骨髓基质细胞层的支持下,多细胞因子可有效地促进脐血造血细胞的扩增,并优于单用细胞因子及骨髓基质细胞,证实骨髓基质细胞可协同多细胞因子有效地促进脐血单个核细胞的扩增,促进造血干细胞的黏附和趋化能力。     

CD133 cells from human umbilical cord blood reduce cortical damage and promote axonal growth in neonatal rat organ co-cultures exposed to hypoxia

To evaluate the effect of CD133⁺ cells (endothelial progenitor cells) on the hypoxia-induced suppression of axonal growth of cortical neurons and the destruction of blood vessels (endothelial cells), we used anterograde axonal tracing and immunofluorescence in organ co-cultures of the cortex and the spinal cord from 3-day-old neonatal rats. CD133⁺ cells prepared from human umbilical cord blood were added to the organ co-cultures after hypoxic insult, and axonal growth, vascular damage and apoptosis were evaluated. Anterograde axonal tracing with 1,1′-dioctadecyl-3,3,3′,3′-tetramethylindocarbocyanine perchlorate was used to analyze axonal projections from the cortex to the spinal cord. Immunolabeling co-cultured tissues of the cortex and the spinal cord were used to investigate the effect of CD133⁺ cells on the survival of blood vessels and apoptosis in the brain cortex. Hypoxia remarkably suppressed axonal growth in organ co-cultures of the cortex and the spinal cord, and this suppression was significantly restored by the addition of CD133⁺ cells. CD133⁺ cells also reduced the hypoxia-induced destruction of the cortical blood vessels and apoptosis. CD133⁺ cells had protective effects on hypoxia-induced injury of neurons and blood vessels of the brain cortex in vitro. These results suggest that CD133⁺ cell transplantation may be a possible therapeutic intervention for perinatal hypoxia-induced brain injury.     

骨髓基质细胞联合细胞因子对脐血单个核细胞表面抗原表达的影响**

背景：课题组已建立胎儿骨髓基质细胞联合细胞因子的造血细胞体外培养体系,该培养体系能否有效扩增各个发育阶段的造血细胞有待验证。 目的：观察骨髓基质细胞联合细胞因子培养体系对脐血单个核细胞表面抗原CD133、CD34表达的影响。 方法：将从脐血标本中分离出来的单个核细胞接种于无血清培养体系,实验分为3组：①F组：干细胞因子+Flt3配体+促血小板生成素+单个核细胞。②S组：基质细胞+单个核细胞。③SF组：基质细胞+干细胞因子+Flt3配体+促血小板生成素+单个核细胞。在第0,6,10,14天检测有核细胞总数、CD133+、CD34+、CD133+CD34+细胞数以及集落形成单位数。 结果与结论：SF组有核细胞总数在各个检测时间点均比其他两组高;除了第14天外,第6、10天两个时间点SF组中CD133+、CD34+、CD133+CD34+细胞及集落形成单位数均高于其他组;含骨髓基质细胞的S组和SF组中CD133+细胞/有核细胞、CD34+细胞/有核细胞、CD133+CD34+细胞/有核细胞的比例保持在较高的水平。结果说明骨髓基质细胞联合细胞因子能有效的扩增脐血单个核细胞及其中的CD133+、CD34+、CD133+CD34+细胞,基质细胞对维持造血干细胞的原始性具有重要的作用。     

In vitro characterization of a human neural progenitor cell coexpressing SSEA4 and CD133

The stage-specific embryonic antigen 4 (SSEA4) is commonly used as a cell surface marker to identify the pluripotent human embryonic stem (ES) cells. Immunohistochemistry on human embryonic central nervous system revealed that SSEA4 is detectable in the early neuroepithelium, and its expression decreases as development proceeds. Flow cytometry analysis of forebrain-derived cells demonstrated that the SSEA4-expressing cells are enriched in the neural stem/progenitor cell fraction (CD133(+)), but are rarely codetected with the neural stem cell (NSC) marker CD15. Using a sphere-forming assay, we showed that both subfractions CD133(+)/SSEA4(+) and CD133(+)/CD15(+) isolated from the embryonic forebrain are enriched in neurosphere-initiating cells. In addition CD133, SSEA4, and CD15 expression is sustained in the expanded neurosphere cells and also mark subfractions of neurosphere-initiating cells. Therefore, we propose that SSEA4 associated with CD133 can be used for both the positive selection and the enrichment of neural stem/progenitor cells from human embryonic forebrain.     

Oct-4在激素非依赖性前列腺癌干细胞中的表达及意义

背景：干细胞特异性基因Oct-4在维持干细胞功能和调节干细胞的分化过程中起着关键性作用,了解前列腺癌干细胞中Oct-4的表达,对前列腺癌的预后、复发和耐药的评估具有重要意义。 目的：观察Oct-4在激素非依赖性前列腺癌干细胞中的表达。 设计、时间及地点：观察性实验,于2008-02/10在南昌大学第一附属医院中心实验室完成。 材料：取12例前列腺癌患者手术后组织标本,其中6例在手术前没有经过化疗和激素治疗,另外6例患者经过激素治疗出现抵抗而手术。 方法：制备前列腺癌组织单细胞悬液,流式细胞仪分选未经治疗前列腺癌和治疗后出现耐药的前列腺癌干细胞,RT-PCR和Western blot检测激素非依赖性前列腺癌Oct-4基因和蛋白的表达。 主要观察指标：激素依赖和非依赖性前列腺癌CD133+/CD44+以及CD133-/CD44-细胞的比例;Oct-4基因和蛋白在激素非依赖性前列腺癌CD133+/CD44+、CD133+/CD44-、CD133-/CD44+、CD133-/CD44-细胞的表达。 结果：流式细胞仪检测显示未经过治疗的前列腺癌CD133+/CD44+细胞占(0.83±0.21)%,而CD133-/CD44-细胞多达(95.62±1.35)%;治疗出现激素抵抗的前列腺癌CD133+/CD44+细胞为(54.62±0.86)%,而CD133-/CD44-细胞为(9.56±0.47)%;与其他亚群细胞相比,激素非依赖性前列腺癌CD133-/CD44-细胞Oct-4基因和蛋白显著降低(P < 0.01);CD133+/CD44+细胞Oct-4基因和蛋白表达显著升高(P < 0.01);而CD133+/CD44-和CD133-/CD44+细胞之间Oct-4基因和蛋白表达无显著差异(P > 0.05)。 结论：Oct-4在激素非依赖性前列腺癌干细胞中高表达,可能与前列腺癌的预后和耐药有关。     

脐带间充质干细胞对脐血CD34+细胞体外扩增的影响

背景：体外扩增是目前解决脐带血干细胞移植所面临的单份脐血造血干祖细胞数不足问题的主要手段。已有许多关于不同来源的间充质干细胞联合不同细胞因子支持脐血造血干祖细胞体外扩增的报道,而单独应用间充质干细胞对人脐血CD34+细胞体外扩增的报道仍很少。 目的：观察应用脐带源间充质干细胞作基质层的体外培养体系对脐血CD34+细胞体外扩增的支持作用。 设计、时间及地点：对比观察实验,于2006-03/2007-05在中国医学科学院中国协和医科大学血液学研究所、实验血液学国家重点实验室完成。 材料：经产妇知情同意,采集健康足月分娩胎儿脐带9份。 方法：应用贴壁培养的方法从正常足月出生儿脐带中分离培养间充质干细胞,通过细胞形态学、免疫表型、分化实验进行鉴定。利用免疫磁珠分离法从正常足月出生儿脐带血中分离CD34+细胞。应用3种不同培养体系进行脐血CD34+细胞的体外扩增：单独应用脐带源间充质干细胞作基质层、细胞因子培养体系和间充质干细胞联合细胞因子培养体系。 主要观察指标：应用细胞计数法、集落培养计数法和流式细胞学检测法对扩增后细胞数量、集落形成能力和免疫表型进行分析比较。RT-PCR检测间充质干细胞中细胞因子的表达情况。 结果：培养第14天后,间充质干细胞组的CD34+细胞比例明显高于细胞因子联合间充质干细胞组;CD34+细胞总数为培养前的(4.19±1.37)倍,明显高于细胞因子组。培养第7天和第14天,间充质干细胞组的CD34+CD38-细胞亚群比例均高于另两组。RT-PCR结果显示,脐带源间充质干细胞体外可表达干细胞因子和血小板生成素早期干细胞效应因子。 结论：单独应用脐带源间充质干细胞可有效地对脐血CD34+细胞进行体外扩增,更有利于保持较早期干、祖细胞的扩增。 关键词：间充质干细胞;脐带;脐血;CD34+细胞;体外扩增     

Potential mechanism for recruitment and migration of CD133 positive cells to areas of vascular inflammation

Objective

Mast cells are found in large numbers in atherosclerotic plaques. The present study was conducted to determine whether tryptase stimulation of human coronary artery endothelial cells (HCAEC) would lead to an increase in transmigration of CD133 positive cells (CD133+). In vitro these cells can differentiate into mast cells under the influence of specific cytokines and growth factors.

Methods and Results

CD133+ cells were isolated from umbilical cord blood. They express mRNA for several adhesion molecules that are also utilized in neutrophil migration and can migrate across an HCAEC monolayer. Migration increased significantly when HCAEC were stimulated with tryptase and decreased when CD133+ cells were pretreated with CV3988, a platelet activating factor receptor (PTAFR) antagonist. Following long-term cell culture, these cells stained positively for the presence of tryptase, a mast cell enzyme.

Conclusion

CD133+ cells can be utilized as a mast cell precursor population. The transendothelial migration is facilitated by the presence of tryptase and may utilize the PAF/PTAFR interaction in a manner similar to that involved in neutrophil transmigration. Following transmigration, a subset of these progenitor cells may mature into mast cells in the subendothelial space and play a role in propagation of the inflammatory process in atherosclerosis.     

Rapid neural differentiation of human cord blood-derived mesenchymal stem cells

Human umbilical cord blood (UCB) contains hematopoietic stem cells (HSCs) and mesenchymal stem cells (MSCs), both of which are regarded as valuable sources for cell transplantation and cell therapy. Adherent cells expressing MSCs-related antigens such as SH2, CD13, CD29, and ASMA, have been isolated from a mononuclear cell fraction of human UCB. Under proneurogenic conditions, these UCB-derived adherent cells rapidly assumed the morphology of multipolar neurons. Both immunofluorescence and RT-PCR analyses indicated that the expression of a number of neural markers including Tuj1, TrkA, GFAP and CNPases, was markedly elevated during this acute differentiation. The neurogenic potential of UCB-derived may facilitate stem cell therapeutic approaches to neurodegenerative diseases.     

Blood-forming stem cells are nervous: Direct and indirect regulation of immature human CD34+ cells by the nervous system

The nervous system regulates immunity through hormonal and neuronal routes as part of host defense and repair mechanism. Here, we review the emerging evidence for regulation of human hematopoietic stem and progenitor cells (HSPC) by the nervous system both directly and indirectly via their bone marrow (BM) niche-supporting stromal cells. Functional expression of several neurotransmitter receptors was demonstrated on HSPC, mainly on the more primitive CD34⁺/CD38^?/low fraction. The myeloid cytokines, G-CSF and GM-CSF, dynamically upregulate neuronal receptor expression on human HSPC. This is followed by an increased response to neurotransmitters, leading to enhanced proliferation and motility of human CD34⁺ progenitors, repopulation of the murine BM and their egress to the circulation. Importantly, recent observations showed rapid mobilization of human HSPC to high SDF-1 expressing ischemic tissues of stroke individuals followed by neoangiogenesis, neurological and functional recovery. Along with decreased levels of circulating immature CD34⁺ cells and SDF-1 blood levels found in patients with early-stage Alzheimer’s disease, these findings suggest a possible involvement of human HSPC in brain homeostasis and thus their potential clinical applications in neuropathology.     

细胞因子介导的人脐血单个核细胞体外扩增并重建NOD/SCID小鼠造血及免疫功能

背景：细胞因子介导的脐血造血细胞体外扩增有望能解决脐血移植数量不足的问题。 目的：实验拟确立在无基质培养条件下体外扩增脐血单个核细胞最合适的细胞因子组合及干细胞因子、FLT3配基协同促聚核细胞生成因子对造血及免疫重建功能的影响。 方法：将新鲜脐血标本分离的单个核细胞接种于含有不同细胞因子组合的无血清无基质培养体系中培养7 d,根据不同细胞因子组合分组,将3因子干细胞因子+FLT3配基+促聚核细胞生成因子组合在无血清无基质条件下扩增培养7 d前后的脐血单个核细胞移植给经亚致死量照射的NOD/SCID小鼠。在扩增培养0,7 d检测脐血CD34+细胞数及CD34+CXCR4+,CD34+CD62L+,CD34+CD49d+的细胞数。脐血移植6周后通过流式细胞仪,PCR法检测存活小鼠体内的人源性细胞。 结果与结论：移植6周后,存活小鼠体内均可检测到人源性CD45+细胞,扩增脐血移植组的NOD/SCID小鼠存活率和人特异性基因捡出率均高于新鲜脐血移植组和高于生理盐水移植组 (P < 0.05)。扩增脐血组存活NOD/SCID小鼠骨髓中可检测到人髓系细胞(CD33+),T淋巴细胞(CD4+),B淋巴细胞(CD19+)和人造血干细胞成分(CD34+)细胞的表达。结果提示干细胞因子+FLT3配基+促聚核细胞生成因子3因子组合脐血造血细胞体外扩增是最合适的细胞因子组合,其扩增的脐血单个核细胞能够植入并重建NOD/SCID小鼠的造血及免疫功能。     

CD34-positive cells in human umbilical cord blood express nerve growth factor and its specific receptor TrkA

In this study, we investigated whether hematopoietic stem cells (HSC) and progenitors present in human cord blood can express nerve growth factor (NGF)-specific receptors, TrkA and p75. Our results showed a marked expression of TrkA and NGF in cord blood CD34(+) cells. A gradient of TrkA and NGF expression exists and is highest in cord blood CD34(+) cells, reduced in cord blood mononuclear cells (MNC) and minimal in mononuclear cells isolated from adult peripheral blood.Our findings suggest that NGF may play a role in the differentiation of hematopoietic progenitors and indicate a different requirement for NGF by immune cells, depending on their state of maturity.     

Enhancement of neovascularization with cord blood CD133+ cell-derived endothelial progenitor cell transplantation

The endothelial progenitor cells (EPCs) are responsible for postnatal vasculogenesis in physiological and pathological neovascularization and have been used for attenuating ischemic diseases. However, EPCs from umbilical cord blood (CB) were not well understood and the homing mechanisms of EPCs remain unclear. To determine the potential application of CB-derived EPCs, we established a culture system to induce the differentiation of CB cells into EPCs. Purified CB CD133(+) cells proliferated and, after further vascular endothelial growth factor receptor 2 (VEGFR-2) antibody purification, differentiated into EPCs expressing endothelial markers, such as VE-cadherin, VEGFR-2, CD31, von Willebrand factor (vWF) and Weibel-Palade bodies. These cells could also take up acetylated lower density lipoprotein (Ac-LDL) and bind Ulex europaeus agglutinin-1 (UEA-1).When expanded EPCs were transplanted via tail vein into nude mice, they incorporated into capillary networks in ischemic hindlimb, augmented neovascularization, and improved ischemic limb salvage. In addition, in ischemic tissue, there were elevated expressions of VEGF and stromal derived factor 1 alpha (SDF-1 alpha), both of which had chemotactic effect on EPCs. Moreover, P-/E-selectins was found on mouse ischemic endothelium and P-selectin glycoprotein ligand-1 (PSGL-1) on CB-derived EPCs. Neutralizing antibody against PSGL-1 blocked the homing of EPCs to ischemic area by 61%. These results demonstrate that CB CD133(+) cell-derived EPCs can be applied for therapeutic neovascularization in ischemic diseases, and reveal important roles of chemoattractants and adhesive molecules in the homing of EPCs.     

GDNF基因真核表达载体的构建及其在脐血CD34+干细胞的表达

目的构建人胶质细胞源性神经营养因子(GDNF)基因的新型真核表达载体,为进行GDNF基因修饰的脐血干细胞移植治疗脑梗死奠定基础。方法将GDNF基因克隆到增强型绿色荧光蛋白(EGFP)真核表达载体中,进行酶切鉴定及DNA测序分析,并将携带有GDNF基因的该真核表达载体,通过脂质体介导,转染人脐血CD34 细胞,荧光显微镜、ELISA检测转基因脐血干细胞GDNF的表达与释放。结果经双酶切鉴定和测序证实已将GDNF基因DNA片段正确插入到真核表达载体中,并能在脐血CD34 干细胞中表达、分泌有活性的GDNF。结论成功构建pEGFP/GDNF基因新型真核表达载体。     

人外周血内皮祖细胞培养方法的建立

背景：成人外周血来源丰富,但内皮祖细胞含量较少,为使其能够更好的应用于组织工程及细胞治疗,有必要建立外周血内皮祖细胞成熟、稳定的体外扩增体系。 目的：建立稳定的人外周血分离、培养和体外扩增血管内皮祖细胞的方法。 方法：应用密度梯度离心法,获取外周血单个核细胞,将分选后细胞接种于预先包埋了人纤维连接蛋白的培养板上,加入内皮祖细胞专用培养基中培养3 d后,洗掉非贴壁细胞,培养至第6天,收集贴壁细胞,应用倒置显微镜和苏木精-伊红染色进行细胞形态学观察;采用MTT法和细胞计数测定第1,3代细胞生长曲线;应用流式细胞仪测定祖细胞和内皮细胞系标志,对培养的细胞进行鉴定。 结果与结论：细胞生长曲线测定表明接种后第3天细胞进入指数增生期,至第6天进入平台期,随着传代次数的增加,细胞增殖速度变慢,同时表达干细胞表面标志CD34、CD133和内皮细胞表面标志血管性血友病因子、血管内皮生长因子受体2。证明人外周血可以分离培养内皮祖细胞。     

Flt3配体胞外域的原核表达纯化及对脐血CD34+细胞的扩增作用*

背景：Fms 样酪氨酸激酶3配体(Flt3配体)是一种重要的生长因子,通过激活特定的酪氨酸激酶受体,调控造血细胞的生长、生存和/或分化,具有促进造血干细胞体外扩增的应用潜力。 目的：构建pET32a(+)-hFLext原核表达载体,表达、纯化hFLext蛋白,观察其对脐血CD34+细胞的扩增作用。 方法：克隆hFLext,构建pET32a(+)-hFLext重组表达载体。转化大肠杆菌 BL21,IPTG诱导蛋白表达,镍珠亲合层析纯化蛋白。磁珠分选脐血CD34+细胞,单独加入hFLext或联合干细胞因子、血小板生成素孵育1周,观察体外扩增作用。 结果与结论：成功克隆hFLext,并构建了pET32a(+)-hFLext重组表达载体。在大肠杆菌BL21成功表达Trx-hFLext融合蛋白,经8 mol/L尿素变性包涵体蛋白,逐步透析复性,镍珠亲合层析纯化蛋白,成功获得高纯度的Trx-hFLext融合蛋白。Trx-hFLext融合蛋白不仅具有维持及轻度刺激CD34+细胞体外扩增的作用,并且与干细胞因子及血小板生成素具有协同作用,为造血干/祖细胞体外扩增研究奠定了基础。     

未破裂颅内动脉瘤患者外周血内皮祖细胞数量的研究

目的 研究颅内动脉瘤与外周血中内皮祖细胞(EPCs)数量的关系.方法 选择未破裂颅内动脉瘤患者24例和正常对照者16例,用密度梯度离心法获取外周血单个核细胞,加入培养基进行选择性培养,分析14 d后细胞形成的集落数,并对贴壁细胞进行细胞鉴定、分析和计数.激光共聚焦显微镜下观察其吞噬荆豆凝集素和乙酰化低密度脂蛋白的内皮功能;用流式细胞仪检测CD34、CD133和血管内皮生长因子受体2(VEGFR-2)三抗阳性细胞并计数.结果 颅内动脉瘤患者外周血EPCs计数较对照组明显减少,流式分析结果显示三抗阳性细胞数比例有显著性差异.结论 颅内动脉瘤患者外周血EPCs的数量较无动脉瘤者明显降低.     

LFA-1 and VLA-4 involved in human high proliferative potential-endothelial progenitor cells homing to ischemic tissue

Cumulative evidences have revealed that endothelial progenitor cell (EPC) transplantation can promote the neovascularization in ischemic tissue, but the mechanism of EPCs homing to the site of ischemia is poorly understood. In this study, to investigate the mechanism of human umbilical cord blood-derived high proliferative potential-endothelial progenitor cells (HPP-EPCs) homing to ischemic tissue we evaluated the expression of lymphocyte function-associated antigen-1 (LFA-1, or CD11a/CD18) and very late antigen-4 (VLA-4, or CD49d/CD29) in EPCs and the changes of expression level of their ligands, intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1), in ischemic tissue and performed the adhesion and migration assays to analyze the interaction between the receptors and ligands. Furthermore, we studied the roles of LFA-1 and VLA-4 in EPC homing in an ischemic model of mice. The results show that LFA-1 andVLA-4 were expressed in HPPEPCs and ICAM-1 and VCAM-1 were expressed in vessel endothelium in ischemic tissues. The pre-incubation of HPP-EPCs with neutralizing antibodies against CD11a or CD49d reduced adhesion and migration of HPP-EPCs in vitro and reduced recovery of hind-limb blood flow, capillary density and incorporation of HPP-EPC into ischemic tissues in vivo. Furthermore, the pre-incubation of HPP-EPCs with the combination of CD11a and CD49d antibodies led to synergistically negative effects on adhesion and transmigration of HPP-EPCs in vitro, and on the homing of HPP-EPCs to ischemic tissue and on neovascularization capacity in vivo. These results indicate that LFA-1 andVLA-4 are involved in HPP-EPC homing to ischemic tissues.