Sertoli cell-mediated differentiation of male germ cell-like cells from human umbilical cord Wharton’s jelly-derived mesenchymal stem cells in an in vitro co-culture system

Background

Microenvironment signals play a critical role in directing the differentiation of stem cells. Sertoli cells (SCs) provide a unique microenvironment that is essential for germ cell differentiation.

Methods

Our previous study has demonstrated that human umbilical cord Wharton’s jelly-derived mesenchymal stem cells (HUMSCs) could differentiate towards male germ cells in vitro, but HUMSC-derived germ-like cells expressed only few germ cell markers. The aim of this study was to investigate the effect of SCs on the differentiation of HUMSCs towards male germ cells using a co-culture system that mimicked the in vivo male germ cell microenvironment.

Results

HUMSCs formed clump-like features on SC monolayers after seeding for 3 weeks. Differentiated cells formed round colonies that share the morphological features of spermatogonial colonies. RT-PCR, immunofluorescence, confocal microscopy, and Western blot analyses revealed the expression of early germ cell markers STELLA and VASA and male germ cell-specific marker DAZL in differentiated HUMSCs, confirming the presence of cells with characteristics of male germ cells.

Conclusion

The HUMSC-SC co-culture system mimics a native microenvironment for germ cell colonization without any in vitro artificial manipulation and can be used to explore the mechanisms controlling the differentiation of male germ cells from HUMSCs. Male germ cells derived from HUMSCs may be used in the therapy for male infertility.     

The roles of mesenchymal stem cells（MSCs） therapy in ischemic heart diseases

Growing cell-based myocardial therapies which could lead to successful myocardial repair attracts medical interest. Even more intriguing is the observation that MSCs appears to be a more potent material among kinds of stem cells for the transplantation, the mechanism for this benefit remains unclear. However, the therapeutic contribution of MSCs to myocardial repair can be caused by multiple factors including： direct differentiation into cardiac tissue including cardiomyocytes,     

Effects of co-engraftment of Schwann cells with neural stem cells into rats with Parkinson disease

Neural stem cells （NSCs） are effective in treating Parkinsonian animals. Although cell transplantation is considered a promising treatment for Parkinson disease （PD）, its clinical use has been limited to only a few patients. The major limiting factors of this therapy are difficulty in obtaining sufficient viable embryonic mesencephalic tissue and the controversial ethical and/or legal issues raised by the use of human fetal allografts. Some reports suggest that Schwann cells （SCs） can promote the proliferation of embryonic stem cells and the induction of dopaminergic neurons. Our research focused on potential curative effects of co-graft SCs with mesencephalic stem cells into Parkinsonian animals and elucidating the underlying mechanisms.     

Human bone morphogenetic protein-2 gene transfer induces human mesenchymal stem cell proliferation and differentiation in vitro

To identify eukaryotie expression veetor of human bone morphogenetie protein 2 peDNA3/BMP2, verify its expression in transfected hulnan mesenchynlal stem cells(hMSCs) and the effect on hMSCs differentiation. Methods: The BMP2 gene was cloned into a eukaryotic expression veetor pcDNA3. Transfeeted the reeombinant into hMSCs by liposome, Lmmunnohistochemistry and it situ hybridization methods were used to identify the expression of BMP2 mRNA and protein; ALP and Von Kossa stains were performed to identify the BMP2 gene differentiated effect on the hMSCs. Resuits: The pcDNA3/BMP2 fragments were as large as theory. BMP2 mRNA and protein were espressed and synthesized both in 48 h and 4 weeks after transfeetion, the ALP and Ca deposit eshibitiio, which marked the osteogenie lineage of hMSCs, were enhanced and Sped. Conclusion: Transfeetion of pcDNA3/BMP2 is able to provide transient and persistent expressionin hMSCs, and promote the MSCs differentiation to osleogenic lineage.     

Very small embryonic like（VSEL） stem cells

It is generally accepted that adult bone marrow(BM) contains both hematopoietic stem cells(HSCs) and mesenchymal stem cells (MSCs). Recently, a rare population of stem cells different from HSCs and MSCs were identified in murine BM and human cord blood (CB), named as very small embryonic like(VSEL) stem cells. These cells are tiny round and CXCR4 Sca-1 Lin- CD45-, expressing SSEA-1/4, Oct-4 and Nanog, which have potent of differentiation into all three germ-layer lineages, such as cardiomyocytes, neural and pancreatic cells.     

Growth and differentiation of neural stem cells with superparamagnetic iron oxides labeling in vitro

Objective： To study the growth and differentiation of superparamagnetie iron oxides（SPIOs） labeled neural stem cells （NSCs）. Methods： After NSCs were cultured and subcuhured from newborn rat brain, they were magnetically labeled with ferumoxides （a kind of SPIOs ）. Growth, differentiation and other biology properties of the cells were investigated with immunocytochemistry, transmission electron microscopy （TEM） and Prussian blue staining. Results： Nestin positive cells were found in the culture and offspring clones. NSCs could be differentiated into positive GFAP and NF200 cells in serum culture. When NSCs incubated with ferumoxides, the iron particles were seen in intracellular as well as in offspring clones. With the increase in concentration of ferumoxides （5.6-11.2/μg/ml）, ferumoxides showed no significant difference effects on the growth and differentiation of NSCs. When the concentration of ferumoxides exceeded 22.4μg/ml ,there was significant difference（P〈0.05）. Conclusion： We successfully label NSCs with ferumoxides,it is useful for tracking of magnetic labeled NSCs in vivo with MRI.     

Immunomodulatory effects of mesenchymal stem cells from adipose tissue in a rat orthotopic liver transplantation model

Objective To investigate immunomodulatory effects of adipose-derived mesenchymal stem ceils in a rat orthotopic liver transplantation model. Methods Mesenchymal stem ceils were isolated from adipose tissue of SD rats. In in vitro mixed lymphocyte culture system by using Wistar T cells as responders and SD spleen cells as stimulators,[第一段]     

Mesenchymal stem cells over-expressing hepatocyte growth factor improve small-for-size liver grafts regeneration

Ischemia-reperfusion（I/R） associated with small-for-size liver transplantation（SFSLT） impairs liver graft regeneration. Mesenchymal stem cells （MSCs） have the capability, under specific conditions, of differentiating into hepatocytes. Hepatocyte growth factor （HGF） has potent antiapoptotic and mitogenic effects on hepatocytes during liver injury, and has been utilized in many experimental and clinical applications. In this study, we implanted HGF-expressing MSCs into liver grafts via the portal vein, using a 30% small-for-size rat liver transplantation model. HGF, c-met expression, hepatic injury and liver regeneration were assessed after liver transplantation. Our study demonstrated that MSCs over-expressing HGF prevented liver failure and reduced mortality in rats after SFSLT.     

Experimental study on MyoD gene induced differentiation of bone marrow mesenchymal stem cells into myoblasts in vitor

Objective:To explore the possibility of the transfection of MyoD gene induced bone marrow mesenchymal stem cells(MSCs) to differentiate into myoblasts in vitro.Methods:The eukaryotic expression plasmid vector pIRES2-EGRP-MyoD was transfected into MSCs with lipotransfection method,and the positive cells were selected by G418;The expression of MyoD was detected in the transfected MSCs with RT-PCR and the amplified,purified product was identified by sequencing;The reporter gene enhanced green fluorescence protein(EGFP)was observed in the transfected cells under a fluorescent and a laser confocal microscopes;Immunohistochemical methods was used to examine the expressions of MyoD,myogenin,myosin,myoglobin and desmin in the differentiated,cells.The ultrastructure changes of the cells before and after transfection were observed with electron microscopy.Results:The expression of MyoD was detected in the transfected MSCs with RT-PCR and the amplified,purified product was as same in sequence as thwat from Genbank;Green fluorescence was observed in the transfected cells under a fluorescent and a laser confocal microscopes;Immunohistochemical methods indicated that MyoD,myogenin,myosin,myoglobin and desmin were expressed in the transfected cells;The transfected cells showed the morphologcal characteristics of matrue cells with filaments in their cytoplasm.Conclusion:MyoD gene can induce cultured MSCs to successfully differentiate into myoblasts,probably providing an experimental foundation for trauma repair.     

脐带间质干细胞多向分化潜能的鉴定

目的:研究脐带间质干细胞的多向分化潜能,为心血管组织工程研究提供一个新的种子细胞来源?方法:采用胶原酶胰酶消化脐带组织,将获得的细胞传代培养,流式细胞仪鉴定细胞表面分子,再以不同方法使其向骨?脂肪?心肌和内皮细胞方向诱导,分别采用Von Kossa?油红O染色和免疫组化对分化的细胞进行鉴定?结果:脐带间质干细胞分别向成骨细胞和成脂肪细胞诱导培养后,Von Kossa染色和油红O染色阳性?在5-氮胞苷诱导后,心肌特异性抗体肌动蛋白α-actin和肌球蛋白myosin免疫组化染色阳性?在VEGF诱导后,细胞形成网格样结构,免疫荧光示CD31?CD34染色阳性?结论:脐带间质干细胞具有分化为骨?脂肪?心肌和内皮细胞的潜能,是非常有前途的心血管组织工程种子细胞来源?     

人脐血间充质干细胞分离培养及向成骨细胞分化的研究

目的拟建立一套较为简便、有效和实用的人脐血间充质干细胞(MSCs)体外分离培养体系,探讨其向成骨细胞分化的可行性。方法由人脐静脉血获得MSCs,纯化培养后用含地塞米松、β-甘油磷酸钠和维生素C的培养液诱导,通过倒置显微镜观察、碱性磷酸酶染色检测诱导后细胞。结果来源于脐血的单个核细胞经体外培养贴壁后出现形态学上可见间充质样的细胞,间充质样细胞为类似成纤维细胞样的细胞形态。诱导培养的细胞碱性磷酸酶染色呈阳性。结论人脐血MSCs经合理的体外诱导培养后,可以分化为成骨细胞。     

脐血间质干细胞肌源性诱导后细胞生理变化

目的探讨5-氮胞苷(5-aza)、心肌细胞裂解液和心肌诱导液等三种肌源性诱导方法对脐血间质干细胞(MSCs)生理性质的影响。方法MSCs以密度梯度离心法取自足月妊娠犬,免疫组化检测细胞表面抗原,经5-aza、心肌细胞裂解液和心肌诱导液诱导后,Western blotting检测心肌转录因子Nkx2.5的表达,膜片钳检测细胞动作电位,激光共聚焦显微镜检测细胞内游离Ca2 浓度的变化。结果MSCs表达CD29和CD71,不表达CD11a、CD11b和CD34;诱导后三组细胞均有Nkx2.5的表达,5-aza和心肌细胞裂解液诱导后的细胞可检测到动作电位,三组细胞胞内Ca2 浓度不同。结论肌源性诱导后的MSCs只部分具有心肌细胞的生理特性,功能上与心肌细胞的差异仍较为显著。     

人脐带间充质干细胞经添加B27的无血清培养基诱导后分化成神经元样细胞

目的 评价人脐带间充质干细胞（HUCMSCs）经添加B27的无血清培养基诱导后向神经元样细胞分化的能力和效率。方法 将第4代HUCMSCs分为4组：A组：血清培养基（SCM）处理14 d;B组：给予SCM+20 ng/mL神经生长因子（NGF）+10 ng/L碱性成纤维细胞生长因子（bFGF）治疗14 d;C组：无血清培养基（SFM）处理14 d;D组：SFM+20 ng/mL NGF+10 ng/mL bFGF处理。每3 d更换各组细胞培养液。倒置显微镜观察神经球生长情况,流式细胞术分析细胞标记物。巢蛋白（Nestin）、神经元特异性烯醇化酶（NSE）、人重肽神经丝蛋白（NEFH）、神经胶质纤维酸性蛋白（GFAP）通过qRT-PCR和Western blotting进行定量。结果 在诱导前,HUCMSCs表现出丰富的间充质干细胞表面标志物（CD29、CD44和CD105分别为99.5%、49.6%和77.7%）的表达。在第7、10、14天观察神经元样细胞的形成,D组最优,其次是C、B、A组。qRT-PCR和Western blotting结果显示,A、B、C、D组Nestin和GFAP表达逐渐减少,NEFH和NSE表达逐渐增加,A组与其他3组的GFAP、NEFH、Nestin和NSE表达差异有统计学意义（P<0.05）。结论 添加B27的SFM可以有效地将HUMSCs分化为神经元样细胞,添加细胞因子（NGF和bFGF）使分化效 果更显著。     

Notch signaling: a novel regulating differentiation mechanism of human umbilical cord blood-derived mesenchymal stem cells into insulin-producing cells in vitro

Background Human umbilical cord blood-derived mesenchymal stem cells （UCB-MSCs） could be induced to differentiate into insulin producing cells （IPCs） in vitro, which have good application potential in the cell replacement treatment of type-1 diabetes. However, the mechanisms regulating this differentiation have remained largely unknown. Notch signaling is critical in cell differentiation. This study investigated whether Notch signaling could regulate the IPCs differentiation of human UCB-MSCs. Methods Using an interfering Notch signaling protocol in vitro, we studied the role of Notch signaling in differentiation of human UCB-MSCs into IPCs. In a control group the induction took place without interfering Notch signaling. Results Human UCB-MSCs expressed the genes of Notch receptors （Notch 1 and Notch 2） and ligands （Jagged 1 and Deltalike 1）. Human UCB-MSCs with over-expressing Notch signaling in differentiation resulted in the down-regulation of insulin gene level, proinsulin protein expression, and insulin-positive cells percentage compared with the control group. These results showed that over-expressing Notch signaling inhibited IPCs differentiation. Conversely, when Notch signaling was attenuated by receptor inhibitor, the induced cells increased on average by 3.06-fold （n=-4, P 〈0.001） in insulin gene level, 2.60-fold （n=-3, P 〈0.02） in proinsulin protein expression, and 1.62-fold （n=-6, P 〈0.001） in the rate of IPCs compared with the control group. Notch signaling inhibition significantly promoted IPCs differentiation with about 40% of human UCB-MSCs that converted to IPCs, but these IPCs were not responsive to glucose challenge very well both in vitro and in vivo. Hence, further research has to be carried out in the future. Conclusions Notch signaling may be an important mechanism regulating IPCs differentiation of human LICB-MSCs in vitro and Notch signaling inhibition may be an efficient way to increase the number of IPCs, which may resolve the shortage of islet of cell replacement treatment of type-1 diabetes.     

人脐带沃顿胶间充质干细胞对重型再生障碍性贫血调节性T细胞及Foxp3基因的影响

目的研究脐带沃顿胶间充质干细胞(WJCs)对重型再生障碍性贫血(SAA)患者外周血CD4+CD25+调节性T细胞及Foxp3基因表达水平的影响,探讨WJCs对SAA患者T淋巴细胞(TLCs)免疫调节作用的可能机制。方法从人脐带中分离培养WJCs,通过流式细胞术检测其表面标记并进行鉴定;采用密度梯度离心法从SAA患者外周血中分离TLCs;在植物凝集素(PHA)刺激下,将SAA患者TLCs(1×105个)进行体外培养,实验组加入不同数量级WJCs(1×103、1×104、1×105个)共培养,3 d后采用MTT法检测淋巴细胞抑制率;流式细胞仪检测实验组及正常对照组SAA患者TLCs中CD4+CD25+T细胞比例的变化,RT-PCR方法检测Foxp3基因mRNA水平的变化。结果 WJCs能明显抑制SAA患者TLCs增殖,且抑制作用与WJCs呈剂量依赖性;实验组CD4+CD25+T细胞比例以及Foxp3基因表达水平均比对照组明显增加,且与TLCs增殖水平呈负相关。结论 WJCs对SAA患者TLCs的抑制作用呈剂量依赖性,通过上调Foxp3的表达而发挥CD4+CD25+调节性T细胞的免疫调节作用可能是其机制之一。     

人脐带间充质干细胞作为维持人胚胎干细胞生长饲养层细胞的研究

目的寻找可以维持人胚胎干细胞未分化生长的人源性细胞作为饲养层细胞,从而解决使用鼠源性细胞作为饲养层带来的安全问题。方法尝试以人脐带间充质干细胞作为饲养层细胞来培养人胚胎干细胞,检验其是否可以维持人胚胎干细胞的未分化生长状态。用胶原酶消化法分离人脐带间充质干细胞,光镜下观察细胞形态;流式细胞仪检测其表面标志;诱导人脐带间充质干细胞向成骨细胞和脂肪细胞进行分化。将人胚胎干细胞系H1接种于丝裂霉素C灭活后的人脐带间充质干细胞上,每隔5d进行一次传代。培养20代后,对人胚胎干细胞特性进行相关检测,包括细胞形态、碱性磷酸酶染色、相关多能性基因的表达、分化能力。结果从人脐带中分离出的间充质干细胞为梭形,呈平行排列生长或漩涡状生长;细胞高表达CD44、CD29、CD73、CD105、CD90、CD86、CD147、CD117,不表达CD14、CD38、CD133、CD34、CD45、HLA-DR;具有分化成脂肪细胞和成骨细胞的潜能。人胚胎干细胞在人脐带间充质干细胞饲养层上培养20代后,继续保持人胚胎干细胞的典型形态,碱性磷酸酶染色为阳性,免疫荧光染色显示OCT4、Nanog、SSEA4、TRA-1-81、TRA-1-60的...     

人骨髓间质干细胞向脂肪细胞诱导分化过程中端粒酶活性的变化

目的观察体外培养人骨髓间质干细胞(mesenchymal stem cells,MSCs)成脂分化过程中端粒酶活性的变化规律,并探讨其可能的机制。方法通过贴壁培养法从人骨髓中分离MSCs,利用造血干细胞相关表面抗体对MSCs进行表型鉴定,利用相应诱导分化剂,诱导MSCs向成骨细胞、脂肪细胞和神经元样细胞分化,分析其多向分化潜能。以端粒重复序列扩增法(TRAP)检测MSCs及MSCs诱导成脂分化过程中端粒酶活性;以Western印迹法检测MSCs及MSCs诱导成脂分化过程中端粒酶反转录酶(hTERT)及端粒相关蛋白[端粒重复序列结合因子1(TRF1)、端锚聚合酶1(Tankyrase 1)]的表达水平。结果 TRAP法检测传代培养的MSCs端粒酶呈阴性表达,而MSCs诱导成脂分化过程中,端粒酶活性明显升高,以第7天最高(P<0.05),其后呈下降趋势;Western印迹法检测显示,hTERT在MSCs中有微弱表达,在MSCs诱导成脂分化过程中,hTERT和Tankyrase 1表达水平升高,以第7天最高,此后逐渐下降,而TRF1表达水平保持不变。结论体外培养的MSCs端粒酶呈微弱表达,MSCs在成脂诱导分化过程中,端粒酶活性先升高,其后逐渐下降,而Tankyrase 1可能在其中发挥重要作用。     

大鼠骨髓间充质干细胞向成肌细胞诱导分化的研究

目的研究5-氮杂胞苷诱导大鼠骨髓间充质干细胞向成肌细胞方向分化的最佳诱导浓度及诱导后细胞的活性,以得到稳定分化的成肌细胞.方法应用不同浓度的5-氮杂胞苷进行定向诱导分化,3H-TdR掺入试验检测诱导后细胞的活性状况,筛选出最佳的时相-浓度结合点,通过免疫组化鉴定分化结果.结果在10μmol/L5-氮杂胞苷诱导培养后15d细胞活性较好,免疫组化技术鉴定其已向成肌细胞方向分化.结论10μmol/L5-氮杂胞苷可成功诱导其向成肌细胞分化.为临床上以细胞注射治疗女性压力性尿失禁提供实验依据.