不同诱导条件对小鼠胚胎干细胞分化为心肌细胞的实验研究

目的 :比较小鼠胚胎干细胞 （ESC）在不同诱导条件下分化为心肌细胞的分化比率。方法 :用鼠胚成纤维细胞（MEF）作为饲养层促进 ESC增殖并抑制其分化 ,用维甲酸 （RA ）、二甲基亚砜 （DMSO）、转化生长因子β1 （TGF-β1 ）、激活素 - A（activin- A）为分化诱导剂 ,采用三步法诱导 ESC分化为心肌样细胞 ,并比较各组分化比率。结果 :各组实验用的各种诱导剂均能诱导 ESC分化为心肌样细胞 ,尤以 TGF- β1 （2 ng/m l）、activin- A（2 0 ng/ml）及 2 0 %胎牛血清 （FCS）组成的分化培养基可以使其分化比率高达 88% ,显著高于其它各组 （P<0 .0 1）。结论 :以 MEF饲养层培养 ,TGF- β1 、activin- A作分化诱导剂可作为一种比较简便、稳定、高效的 ESC分化条件。     

胚胎干细胞的定向心肌分化及调控

胚胎干细胞是具有分化为三个胚层来源的各种类型组织细胞潜能的多能干细胞,可在体外无限增殖。信号分子、化学诱导剂、激素和细胞内转录因子可诱导和调控胚胎干细胞进行心肌细胞分化,为干细胞移植用于心肌再生和改善心功能提供了潜在的细胞来源。     

胚胎干细胞向心肌细胞诱导分化的研究进展

胚胎干细胞具有多向分化潜能,在器官移植及组织修复治疗方面具有广阔的应用前景。近来研究表明,胚胎干细胞在相关基因、转录因子调控以及体内外细胞因子、激素、微环境等作用下能够诱导分化为心肌细胞。但临床应用胚胎干细胞进行心脏修复治疗还有许多问题需要研究和解决。     

胚胎干细胞向心肌细胞诱导分化的研究进展

胚胎干细胞具有多向分化潜能,在器官移植及组织修复治疗方面具有广阔的应用前景.近来研究表明,胚胎干细胞在相关基因、转录因子调控以及体内外细胞因子、激素、微环境等作用下能够诱导分化为心肌细胞.但临床应用胚胎干细胞进行心脏修复治疗还有许多问题需要研究和解决.     

曲古菌素A联合细胞因子体外诱导小鼠胚胎干细胞分化为肝细胞

目的:建立细胞因子和曲古菌素A(trichostatin A,TSA)联合诱导小鼠胚胎干细胞(embryonic stem cell,ESC)向肝细胞分化的3步法.方法:ESC在含激活素A的不含白血病抑制因子的培液中培养3 d分化为定形内胚层细胞;然后加入酸性成纤维细胞生长因子和T S A联合诱导5 d,再加入肝细胞生长因子(hepatocyte growth factor,HGF)等诱导因子培养5 d,向肝细胞方向分化,最后以致瘤素M、地塞米松继续培养5 d形成成熟肝细胞.自发分化组做阴性对照组不加上述因子,不含白血病抑制因子(leukemia inhibitory factor,LIF)的培养液进行自发分化培养.结果:诱导分化18 d后,用光镜、免疫荧光、RT-PCR检测显示诱导18 d后,出现了大量类肝脏细胞表型的上皮细胞,RT-PCR检测显示这些细胞表达成体肝脏细胞特异标记如酪氨酸转氨酶、白蛋白(albumin,ALB)、天冬氨酸转氨酶、甲状腺激素结合蛋白等.细胞免疫荧光也显示为甲胎蛋白、ALB、细胞角蛋白18阳性,分化细胞具有成熟肝脏细胞所具有的糖原储存、吲哚菁绿摄取和释放功能.其分化效率用ALB阳性率表示,诱导分化率可达57.38%.结论:组蛋白去乙酰化酶抑制剂TSA联合细胞因子体外诱导ESC可以成功分化为肝细胞,从而为体外获得大量肝细胞对肝病的临床细胞移植治疗及其研究提供理论和实践基础.     

应用胚胎干细胞研究心肌细胞发育过程的一种模型

本文概述了鼠胚胎干细胞在体外分化成的心肌细胞的形态特征、分类以及电生理特性及其应用前景。     

维生素C促进小鼠胚胎干细胞分化为心肌细胞的实验研究

目的:利用经典的悬滴培养法形成拟胚体(EBs),诱导小鼠胚胎干细胞(m ESCs)在体外分化为心肌细胞,观察维生素C作为诱导剂对m ESCs体外诱导分化为心肌细胞的影响,进而寻找一种高效、安全的诱导方法。方法:复苏m ESCs,传代培养后,利用悬滴法使m ESCs形成拟胚体,用含0.1mg/m L维生素C的分化培养基对其进行诱导分化,以不添加任何诱导剂作为对照组,观察出现搏动拟胚体的时间,搏动拟胚体的数量,计算分化比率,统计搏动频率,并进行免疫荧光染色测定心肌肌钙蛋白T(c Tn T)的表达。结果:小鼠胚胎干细胞可自发分化为心肌细胞,但效率较低,0.1mg/m L的维生素C能明显提高m ESCs分化为心肌细胞的效率,约83.3%的EBs出现搏动,显著高于未添加任何诱导剂组,搏动频率为(81.2±7.8)次/分钟。两组搏动心肌细胞c Tn T免疫染色阳性。结论:维生素C能够显著提高m ESCs向心肌细胞分化效率,应用维生素C体外诱导m ESCs向心肌细胞分化是一种较为理想的体外诱导方式。     

胰高血糖素样肽1诱导小鼠胚胎干细胞E14分化为胰岛素表达细胞

将小鼠胚胎干细胞株E14以高血糖素样肽 1(GLP 1)诱导 ,观察细胞形态 ,用原位杂交和RT PCR检测细胞内胰岛素mRNA的变化 ,免疫组化、流式细胞仪、放射免疫法验证细胞是否能分泌胰岛素样物质。发现E14细胞在GLP 1的作用下可以分化成表达胰岛素样物质的细胞     

胚胎干细胞及其心肌细胞定向分化研究进展

近年来 ,胚胎干细胞已成为生命科学研究的热点之一。作者在回顾胚胎干细胞的生物学特性、获取和培养方法的基础上 ,着重综述在胚胎干细胞分化为心肌细胞后 ,心肌细胞特异性基因表达的变化、电生理特征、离子通道出现、形态学特征和治疗心肌梗死实验的初步结果     

转录因子Tbx18及Wt1在小鼠心脏发育过程中的时空表达

目的:原位观察转录因子Tbx18及Wt1在胚胎心脏中的表达,及心肌细胞本身是否表达Tbx18及Wt1。方法:收集不同发育阶段小鼠胚胎(E)心脏,冰冻切片后,取不同区域的组织进行免疫荧光染色和DAPI染核,检测Tbx18、Wt1及Nkx2.5的表达。结果:小鼠前体心外膜及不同发育阶段的心外膜可明显表达Tbx18及Wt1蛋白,但未检测到心脏转录因子Nkx2.5的表达。从E10.5~至少E14.5d,Tbx18蛋白明显表达于不同区域的心脏组织中。除E14.5 d少许表达Tbx18的细胞不表达Nkx2.5外,这些表达Tbx18的细胞还同时表达Nkx2.5。从E12.5~至少14.5 d,Wt1表达于不同区域心脏组织中,但这些表达Wt1的细胞都不表达NKx2.5。结论:从E10.5~至少14.5 d,Tbx18表达于小鼠心肌细胞中;从E12.5d~至少E14.5d,Wt1表达于小鼠心脏组织中,但不表达于心肌细胞中。     

间充质干细胞的生物特性及其在冠心病治疗中的临床应用

间充质干细胞(m esenchym al stem cells,MSCs)是一些易于在体外扩增并且具有多种分化能力的原始细胞,它在适宜的环境中可以分化为骨、软骨、脂肪、纤维结缔组织、骨髓基质等不同细胞。已有大量试验研究MSCs的分离、纯化、培养,以及它的特性,并有临床前期的研究实验证实了MSCs对冠心病的治疗效果,现将上述国内外研究现况予以综述,并对尚未明确的相关问题进行探讨。     

Role of stromal-derived factor-1 in the hematopoietic-supporting activity of human mesenchymal stem cells

Mesenchymal stem cells (MSC) have the ability to support and maintain hematopoiesis in vitro. However, mechanisms implicated in this support are not fully characterized. In the present study, the role of stromal-derived factor-1 (SDF-1)/CXCR4 axis in the interactions between MSC and hematopoietic stem/progenitor cells (HSPC) was studied. Human bone marrow MSC were plated as feeder layers in Dexter-type long-term cultures (LTC) with human cord blood CD34(+) HSPC. Cultures were supplemented weekly with neutralizing antibodies against CXCR4 or SDF-1 for 5 wk. LTC-initiating cell (IC) activity was strongly dependent on the SDF-1/CXCR4 axis, as both antibodies significantly decreased secondary colony-forming cell production. To assess the effect of SDF-1/CXCR4 axis on progenitor cell proliferation, LTC-IC killing assays were carried out: in LTC of CD34(+) cells in contact with MSC, treatment with anti-CXCR4 antibody significantly reduced the number of cycling progenitors. These results indicate that the SDF-1/CXCR4 axis promotes HSPC proliferation in contact with MSC. Interestingly, when HSPC were separated from MSC by a semipermeable membrane, LTC-IC activity became CXCR4 independent. Multiplex analysis of MSC-conditioned medium revealed that in addition to SDF-1, MSC produced stimulatory and inhibitory factors, such as interleukin (IL)-6, IL-11, granulocyte macrophage-colony stimulating factor as well as monocyte-chemoattractant protein-1. Altogether, human MSC support hematopoiesis in Dexter-type cultures through the activation of the SDF-1/CXCR4 axis. Our data further suggest that SDF-1 stimulates retention of HSPC in MSC niches which expose them to stimulatory and inhibitory factors in a paracrine manner.     

Early Cardiac Catheterizations within 30 Days Post Congenital Heart Surgery in Children

Background: This study set out to assess the indications, feasibility, safety, and outcome of early cardiac catheterizations (CC) within 30 days after congenital heart surgery (CHS) in children. Methods and Results: This is a retrospective, single-center case review study of all CC within 30 days after CHS between 1/2010-12/2020. A total of 317 (138 diagnostic, 179 interventional) CC were performed in 245 patients at a median of 4 days (IQR 13) after CHS. The median age was 3 months (IQR 6), and body weight was 5 kg (IQR 4). A total of 194 (61.2%) CC were performed in patients with univentricular hearts. CC revealed significant pathologies leading to early redo-surgery in 37 patients (12%). The transcatheter interventions primarily were needed in patients after cavo-pulmonary connection (n = 69%, 21.8%), right ventricle to pulmonary artery conduit (n = 39%, 12.3%), and Norwood-I surgery (n = 34%, 10.7%) presenting with hypoxemia, prolonged postoperative course, and suspected arterial stenosis on echocardiography. The clinical impact of an early postoperative transcatheter intervention for the following clinical course was high in most cases. There were nine (2.8%) major and 20 (6.3%) minor intra-procedural complications. Risk factor analysis revealed no difference for the occurrence of complications for patients’ age, weight, and time from initial CHS, underlying uni- vs. biventricular heart disease, or ECMO. Conclusion: Early CC within 30 days after CHS in children can be performed safely with a high diagnostic and therapeutic value. The rate of complications is low, while the therapeutic consequence is relevant.     

Beclin 1 Biology and its Role in Heart Disease

Macroautophagy (hereafter termed autophagy) is a highly evolutionarily conserved pathway that degrades intracellular components such as damaged organelles in lysosome. Autophagy occurs at low basal levels in virtually all types of cells, which is required for the maintenance of cellular homeostasis. Beclin 1 protein, encoded by the beclin 1 gene, plays a central role in the regulation of autophagy. Beclin 1 primarily functions as a scaffolding protein assembling Beclin 1 interactome to regulate Class III PI3K/VPS34 activity, which in turn, tightly controls autophagy at multiple stages. In addition to autophagy, Beclin 1 participates in the regulation of other biological processes such as endocytosis, apoptosis and phagocytosis. Fine-tuning of Beclin 1 protein levels, intracellular localization and the assembly of its interactome is pivotal for the proper execution of these biological functions. Deregulation of Beclin 1 contributes to the pathogenesis of a variety of human diseases. In this review, we summarize biology of Beclin 1 and its role in human pathology, with an emphasis on heart disease.     

Sirtuin 1 regulation of developmental genes during differentiation of stem cells

The longevity-promoting NAD⁺–dependent class III histone deacetylase Sirtuin 1 (SIRT1) is involved in stem cell function by controlling cell fate decision and/or by regulating the p53-dependent expression of NANOG. We show that SIRT1 is down-regulated precisely during human embryonic stem cell differentiation at both mRNA and protein levels and that the decrease in Sirt1 mRNA is mediated by a molecular pathway that involves the RNA-binding protein HuR and the arginine methyltransferase coactivator-associated arginine methyltransferase 1 (CARM1). SIRT1 down-regulation leads to reactivation of key developmental genes such as the neuroretinal morphogenesis effectors DLL4, TBX3, and PAX6, which are epigenetically repressed by this histone deacetylase in pluripotent human embryonic stem cells. Our results indicate that SIRT1 is regulated during stem cell differentiation in the context of a yet-unknown epigenetic pathway that controls specific developmental genes in embryonic stem cells.     

Tbx18在心脏发育中的作用及其研究进展

随着人口老龄化以及基因相关心脏疾病的增多,Tbx18凭借其在心脏发育中的独特作用越来越多地受到国内外专家学者的重视.Tbx18转录因子与损伤修复和心肌再生的相关性更是近年来研究的热点问题.现就其在胚胎发育过程中的表达、在心脏发生发展过程中的功能及重要性几方面对Tbx18近几年的研究进展做一综述.