基因修饰的脂肪间充质干细胞的研究进展

脂肪间充质干细胞（ADSCs）是来源于脂肪组织的具有多向分化潜能的细胞群，是细胞疗法的理想来源。 基因修饰的脂肪间充质干细胞不仅具有ADSCs的全部特性，而且能够高效表达某些外源基因，加强其在疾病治疗中 的疗效，为常规的临床治疗方法难以治愈的疾病带来了新的转机。本文就近年来的相关进展进行综述，以期为基因 修饰的ADSCs在临床研究的应用上提供借鉴。     

Study of lead-induced neurotoxicity in neural cells differentiated from adipose tissue-derived stem cells

Abstract

In recent years, the use of stem cells as a new tool to create an in vitro model for toxicological studies has been considered. Adipose tissue-derived stem cells (ADSCs) are mesenchymal stem cells which have been extracted from adipose tissue by a less invasive method and rapidly propagated in culture medium compared with other sources. These cells have the capacity to differentiate into different cell lineage in vitro including neural cells. The aim of this study was to investigate the effect of lead exposure at various stages of differentiation on the neural differentiation of ADSCs. Third-passaged ADSCs were differentiated to neural cell in differentiation medium during 16?d. The ADSCs were exposed to lead (0.1–100?µg/ml) before differentiation and during differentiation on days 1, 7 and 14. The cell viability was assessed by MTT assay after 48?h. Also expression of β-tubulin III protein and Nestin, NeuN, NF70, Synaptophysin genes were evaluated at the end of differentiation in all treated groups. The results showed that lead had no effect on viability of undifferentiated ADSCs but differentiating cells showed various sensitivities to lead exposure and cells were more vulnerable to lead exposure at early stage of differentiation. Also, lead exposure at different stages of differentiation had various effects on gene expressions. Our study indicated that neural cells differentiated from ADSCs in vitro are sensitive to neurotoxic effect of lead as well-known developmental neurotoxicant, and then ADSCs could be a candidate as an alternative method for assessing neurodevelopmental toxicity potential of chemicals.     

诱导人骨髓间充质干细胞向成骨细胞分化

目的探讨人骨髓间充质干细胞(mesenchymal stem cells，MSCs)向成骨细胞诱导分化的能力。方法选用不同代次的MSCs，使用条件培养基，观察细胞的形态变化，采用细胞化学和免疫组化的方法检测碱性磷酸酶、钙盐沉积及Ⅰ型胶原的表达。结果MSCs在条件培养基中，15d后可见细胞变为多边形，碱性磷酸酶和Ⅰ型胶原染色阳性，形成钙结节，表现成骨细胞分化特点。结论在一定培养条件下成功诱导人MSCs向成骨细胞分化。在骨组织工程学方面MSCs作为种子细胞具有潜在的应用价值。     

Selective enrichment of hepatocytes from mouse embryonic stem cells with a culture system containing cholestatic serum

Aim： There is increasing evidence indicating that embryonic stem （ES） cells are capable of differentiating into hepatocyte-like cells in vitro. However, it is neces- sary to improve the differentiation efficiency so as to promote the clinical application. Here, we report an efficient culture system to support hepatocyte differentiation from ES cells by utilizing cholestatic serum. Methods： One week after the induction of El4 mouse ES cells into hepatocytes with sodium butyrate, cholestatic serum was added into the culture system at various concentrations and hepatocyte-like cells were induced to proliferate. The morphological and phenotypic markers of hepatocytes were characterized using light microscopy, immunocytochemistry, and RT-PCR, respectively. The function of glycogen stor- age of the differentiated cells was detected by Periodic acid-Schiff （PAS） reaction, and the ratio of hepatic differentiation was determined by counting the albumin and PAS-positive cells. Results： In the presence of conditional selective medium containing cholestatic serum, numerous epithelial cells resembling hepatocytes were observed. The RT-PCR analysis showed that undifferentiated ES cells did not express any hepatic-specific markers; however, in the presence of sodium butyrate and conditional selective medium containing cholestatic serum, hepatic differentiation markers were detected. Immunofluorescence staining showed that those ES-derived hepatocytes were αfetoprotein, albumin, and cytokeratin 18 positive, with the ability of storing glycogen. Further determination of the hepatic differentiation ratio showed that the application of cholestatic serum efficiently enriched ES-derived hepatocyte-like cells by inducing lineage differentiation and enhancing lineage proliferation. Conclusion： The conditional selective medium containing cholestatic serum is optimal to selectively enrich hepatocyte-like cells from mixed differentiated ES cells, which may provide a novel method to improve the hepatic differentiation ratio of ES cells.     

肝损伤血清体外诱导人骨髓间充质干细胞分化为类肝细胞

目的探讨肝损伤血清诱导人骨髓间充质干细胞分化为类肝细胞的可行性。方法分离、纯化hMSCs后用含10％肝损伤血清的培养基诱导培养，倒置显微镜连续观察细胞形态变化，并分别于诱导后7、14、21d行免疫细胞化学、糖原染色检测诱导后细胞的功能。结果①MSCs形态均一，呈长梭形；②实验组MSCs在诱导5—7d后细胞形态开始变为不规则圆形、三角形或多角形；③免疫细胞化学：实验组细胞第7天AFP表达呈阳性，第14天AFP表达消失；Alb第14天开始表达，表达量逐渐增强，可持续至第21天；④PAS染色：实验组在诱导21d时细胞有合成糖原的能力，可见胞浆呈红色。结论肝损伤血清可诱导MSCs向类肝细胞分化，为细胞移植治疗肝衰竭提供新的探索思路。     

Study of the chlorpyrifos neurotoxicity using neural differentiation of adipose tissue‐derived stem cells

Chlorpyrifos (CPF) is the most commonly used organophosphorus insecticide which causes neurodevelopmental toxicity. So far, animals have been used as ideal models for neurotoxicity studies, but working with animals is very expensive, laborious, and ethically challenging. This has encouraged researchers to seek alternatives. During recent years, several studies have reported successful differentiation of embryonic and adult stem cells to neurons. This has provided an excellent model for neurotoxicologic studies. In this study, neural differentiation of mouse adipose tissue‐derived stem cells (ADSCs) was used as an in vitro model for investigation of CPF neurotoxicity. For this purpose, mouse ADSCs were cultured in a medium containing knockout serum replacement and were treated with different concentrations of CPF at several stages of differentiation. Cytotoxic effect of CPF and the expression of neuron‐specific genes and proteins were studied in the differentiating ADSCs. Furthermore, the activity of acetylcholinesterase was assessed by Ellman assay at different stages of differentiation. This study showed that up to 500 μM CPF did not alter viability of the undifferentiated ADSCs, whereas viability of the differentiating cells decreased with 500 μM CPF. CPF upregulated the expression of some neuron‐specific genes and seemed to decrease the number of β‐tubulin III and MAP2 proteins‐expressing cells. There was no detectable acetylcholine esterase activity in differentiated ADSCs. In summary, it was shown that CPF treatment can decrease the viability of ADSC‐derived neurons and dysregulate the expression of some neuronal markers through acetylcholinesterase‐independent mechanisms. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1510–1519, 2016.     

人脂肪间充质干细胞分离培养及其生物学特性的实验研究

目的探索人脂肪间充质干细胞（adipose tissue—derived mesenchymal stem cells，ADMSCs）分离培养的方法及体外扩增的条件，观察ADMSCs的生物学特性。方法以腹部手术患者皮下脂肪组织为材料，采用I型胶原酶消化法及贴壁法分离培养ADMSCs，在含10％胎牛血清的低糖DMEM培养基中贴壁培养，倒置显微镜观察，流式细胞仪检测细胞表面标记CD29、CD44、CD105、CD31、CD34、CD106的表达，透射电镜及扫描电镜下观察ADMSCs超微结构，流式细胞仪测定细胞周期。结果原代和传代细胞呈梭形外观，生长增殖能力良好。CD29、CD44、CD105均呈阳性表达，阳性率分别为95.3％、98．6％和86．5％；而CD31、CD34、CD106阳性率分别为3．5％、2．6％、1．3％。透射电镜观察显示ADMSCs表现出早期幼稚细胞形态的特点，流式细胞仪检测显示84．8％的细胞处于G0/G1期。结论酶消化法能有效地从人脂肪组织分离培养人ADSCs，细胞生长稳定，增殖能力活跃，为今后ADMSCs的分离培养提供了更简单有效的方法。     

Microarray analysis of the effects of serum-free medium on gene expression changes in human mesenchymal stem cells during the in vitro culture

We examined the effects of serum-free medium on the gene expression changes in human mesenchymal stem cells (hMSCs) during the in vitro culture using a DNA microarray analysis. In this study, we cultured hMSCs with two kinds of medium; 1) MSCGM (contain 10% fetal bovine serum) or 2) STK2 (serum-free medium developed for mesechymal stem cells multiplication), and compared hMSCs proliferation, cell morphology, and gene expression changes until 50 days culture. Expression analysis was performed with Affymetrix GeneChip Human Genome U133 Plus 2.0 Array. hMSC proliferation was significantly higher in STK2 medium than in MSCGM medium. The cell morphology of hMSC cultured with STK2 was not significantly changed in 50 days culture. The gene expression changes in hMSCs during the in vitro culture were significantly higher in STK2 than in MSCGM. After 50 days culture, 1991 genes were significantly changed the expression levels compared with 3 days in STK2 but not MSCGM. The expressions of genes related to cell cycle, cancer, proliferation, and cell growth were significantly changed by STK2 for 50 days culture. It was also changed by STK2 that the expressions of genes related to the signaling pathways contain various growth factors, such as IGF-1, FGF, TGF-β, EGF, proliferation, and cell cycle. These results suggest that STK2 may be useful to obtain an enough number of hMSC cells for tissue engineered medical devices in short-term, however, it should be recognized that STK2 would alter the expressions of genes related to a variety of signaling pathways in hMSC if the culture period would be extended to obtain a large number of cells.     

Human neural progenitor and stem cells: US20080107633A1

Background: The application is in the field of neural stem cells (NSCs) and cellular therapy. Objective: It aims at establishing conditions for the isolation and propagation of neural progenitor and stem cells from human fetal tissue, with high rate of growth and high yields of differentiation into the neuronal, astroglial and oligodendroglial pathways. Methods: Neural progenitor and stem cells were isolated from fetal forebrain tissue and propagated as neurospheres, in defined medium in the presence of leukemia inhibitory factor (LIF). Three protocols were designed to differentiate human fetal neural progenitor and stem cells into their progenies. Results: The application claims the generation of human fetal neural progenitor and stem cells with a doubling rate between 5-10 days. It claims the differentiation of the neural progenitor and stem cells in vitro, into neurons, astrocytes and oligodendrocytes with high yields, e.g., 20 to 35% for neuronal cells. Conclusion: The establishment of human neural progenitor and stem cells with high rate of growth and high yields of differentiation provides a source of cells for therapy, particularly for the treatment of neurodegenerative diseases, like Alzheimer's and Parkinson's diseases.     

干预NRG-1/ErbB通路对大鼠脂肪干细胞向类窦房结细胞分化的影响

目的探讨在大鼠脂肪干细胞(ADSCs)向心肌样细胞分化的一定时期内,通过干预NRG-1/ErbB通路是否可调控其向类窦房结样细胞或工作肌样细胞分化。方法分离培养大鼠ADSCs,免疫荧光测定细胞相关表面抗原鉴定其干细胞特性。取3代ADSCs加入含10μmol.L-15-氮胞苷(5-Aza)和10μg.L-1bFGF的培养基处理24 h后分3组向心肌样细胞诱导分化,包括对照组、AG1478组、神经调节蛋白-1(NRG-1)组,取正常培养的为ADSCs组。诱导3周后,通过RT-PCR检测各组NKx2.5、HCN4、TBX3、TBX2基因,Westernblot检测TBX3蛋白,膜片钳检测各组动作电位的表达差异。结果 ADSCs加5-Aza诱导3周后表达心脏早期转录因子Nkx2.5及肌钙蛋白,证明5-Aza可以将ADSCs诱导成心肌样细胞。而AG1478组起搏相关基因(HCN4、TBX3、TBX2)的表达明显强于对照组及NRG-1组(P<0.05),TBX3蛋白也强于对照组(P<0.05),并能产生窦房结样动作电位。而NRG-1组Nkx2.5的表达高于对照组及AG1478组(P<0.05),亦能检测到心室肌样动作电位。结论在大鼠AD-SCs向心肌样细胞分化的一定时间内通过干预NRG-1/ErbB通路可使其定向分化为起搏样细胞或工作肌样细胞,这为今后干细胞生物起搏研究做了有益探讨。     

人上睑眶隔脂肪来源的脂肪干细胞的分离培养及鉴定

目的探讨人上睑眶隔来源的脂肪提取脂肪干细胞(ADSCs)的可行性,并进行分离、培养及鉴定。方法取健康成年人上睑眶隔脂肪组织,用胰酶进行消化后收集细胞接种于培养瓶内,采用差速贴壁法纯化细胞。用HE染色、免疫荧光进行细胞鉴定,并进行成脂、成软骨诱导。结果 HE染色显示细胞形态为长梭形,呈漩涡状生长。免疫荧光鉴定结果显示细胞表面抗原CD44、CD29阳性表达,CD106、CD34阴性表达,说明分离培养的细胞是脂肪干细胞。成脂、成骨诱导实验证明所得细胞有多向分化的能力。结论可以从人上睑眶隔脂肪组织提取出ADSCs,并有多向分化能力,为今后ADSCs的取材提供了新的路径。     

Stem cell research in hepatocellular carcinoma

The traditional view that adult human liver tumors, mainly hepatocellular carcinoma (HCC), arise from mature cell types has been challenged in recent decades. The results of several studies suggest that HCC can be derived from liver stem cells. There are four levels of cells in the liver stem cell lineage: hepatocytes, hepatic stem cells/oval cells, bone marrow stem cells and hepato-pancreas stem cells. However, whether HCC is resulted from the differentiation block of stem cells and, moreover, which liver stem cell lineage is the source cell of hepatocarcinogenesis remain controversial. In this review, we focus on the current status of liver stem cell research and their roles in carcinogenesis of HCC, in order to explore new approaches for stem cell therapy of HCC.     

年龄对人脂肪来源间充质干细胞生物学特性的影响

目的 探讨供体年龄对脂肪来源间充质干细胞（ADSCs）体外生物学特性的影响。方法 收集外科腹部术后留取的皮下脂肪组织和外周血,按年龄分为儿童组、成年组和>50岁组,每组10例,分离培养ADSCs;流式细胞术分析ADSCs免疫表型,实时细胞分析系统检测ADSCs增殖细胞指数（CI）及迁移CI,使用不同的诱导分化培养液检测ADSCs向脂肪细胞和成骨细胞的分化能力,实时逆转录-聚合酶链反应检测骨桥蛋白（OPN）和过氧化物酶体增殖物激活受体-γ(PPAR-γ)mRNA表达水平。将ADSCs与植物血凝素刺激的外周血单个核细胞（PBMCs）共培养,酶联免疫吸附试验检测上清液干扰素（IFN）-γ含量。结果 传3代后3组ADSCs形态均为典型的纺锤形,均表达典型间充质干细胞（MSCs）表面标志物CD90、CD105和CD73。与成年组、>50岁组比较,儿童组细胞体外增殖CI、迁移CI及OPN mRNA相对表达水平均增加（P<0.05）。儿童组ADSCs抑制PBMCs的IFN-γ分泌水平优于成年组及>50岁组ADSCs(P<0.05)。结论 儿童来源ADSCs具有更强体外增...     

Amniotic fluid stem cells: a promising therapeutic resource for cell-based regenerative therapy

Stem cells have been proposed as a powerful tool in the treatment of several human diseases, both for their ability to represent a source of new cells to replace those lost due to tissue injuries or degenerative diseases, and for the ability of produce trophic molecules able to minimize damage and promote recovery in the injured tissue. Different cell types, such as embryonic, fetal or adult stem cells, human fetal tissues and genetically engineered cell lines, have been tested for their ability to replace damaged cells and to restore the tissue function after transplantation. Amniotic fluid -derived Stem cells (AFS) are considered a novel resource for cell transplantation therapy, due to their high renewal capacity, the "in vitro" expression of embryonic cell lineage markers, and the ability to differentiate in tissues derived from all the three embryonic layers. Moreover, AFS do not produce teratomas when transplanted into animals and are characterized by a low antigenicity, which could represent an advantage for cell transplantation or cell replacement therapy. The present review focuses on the biological features of AFS, and on their potential use in the treatment of pathological conditions such as ischemic brain injury and bone damages.     

Functional hepatocyte-like cells derived from mouse embryonic stem cells: a novel in vitro hepatotoxicity model for drug screening.

The aim of the present study was to differentiate mouse embryonic stem (mES) cells into a high percentage of hepatocyte-like cells, and to demonstrate their utility as an in vitro hepatotoxicity model. We were able to differentiate 80-90% of mES cells using optimized hepatocyte differentiation medium. These differentiated cells showed typical hepatocyte morphology, expressed hepatic specific genes as shown by RT-PCR and displayed antibody detectable expression of markers specific for hepatic maturation. These hepatocyte-like cells also demonstrated evidence of glycogen storage. These cells when exposed to CCl4, a commonly used hepatotoxicant, showed an elevation of liver function enzymes, SGOT, SGPT and LDH, indicating hepatic damage. Further, this increase was prevented by pre-treatment with N-acetylcysteine, a known anti-oxidant. Thus we propose that the hepatocyte-like cells derived by the present method may prove to be useful as an in vitro model of hepatotoxicity, thereby providing a novel and promising alternative for obtaining large numbers of functional hepatocyte-like cells for in vitro drug metabolism and hepatotoxicity screening of potential drug candidates.     

羟基磷灰石诱导脂肪间充质干细胞成骨分化的实验研究

目的 探究羟基磷灰石（HA）对脂肪来源的间充质干细胞（ADSCs）向成骨分化的影响。方法 分离、纯化 并鉴定C57BL/6小鼠的ADSCs，将HA与ADSCs共培养，CCK-8法检测不同浓度（0、5、10、20、50、100、500 mg/L）的HA 对ADSCs增殖的影响；碱性磷酸酶（ALP）染色检测不同浓度HA对ADSCs成骨分化的影响；实时荧光定量逆转录-聚 合酶链反应（qRT-PCR）检测ADSCs成骨相关基因骨钙素（BGLAP）、碱性磷酸酶（ALP）、Ⅰ型胶原（COL1A1）、骨桥蛋 白（OPN）、Runt相关转录因子2（Runx2）的mRNA表达情况。结果 低浓度HA（≤20 mg/L）对ADSCs增殖的影响较 小，随着HA浓度增加，细胞的增殖活性下降。HA与ADSCs共培养可显著增加其ALP活性，并促进成骨相关基因的 表达（P＜0.01），且HA为20 mg/L时诱导效果较好。结论 HA具有诱导ADSCs向成骨细胞分化的能力，为两者混合 制作成新的骨支架修复材料提供了理论基础。     

脂肪来源间充质干细胞与免疫调节因子间 作用的研究进展

间充质干细胞（MSCs）是中胚层中具有高度自我更新和多向分化潜能的非造血多能干细胞,可以分化为成 脂细胞、成骨细胞、成软骨细胞、肝细胞、心肌细胞、神经元干细胞、胰岛样细胞等。MSCs 具有免疫调节特性,可通过 分泌吲哚胺-2,3-双加氧酶（IDO）和前列腺素 E2（PGE2）来发挥免疫调节作用,同时又能在炎性因子如干扰素 γ （IFN-γ）的预刺激下增强其免疫调节功能。研究发现,在脂肪组织中存在丰富的,使 MSCs 成为成年干细胞非常有吸 引力的来源。本文对目前脂肪来源间充质干细胞（ADSCs）和以上 3 种免疫调节因子之间相互作用的研究进展作一 综述。     

诱导性多能干细胞体外诱导的现状和展望

鉴于人的胚胎干细胞在再生医学、组织工程学和药物研发等领域有极高的应用价值,科学家尝试通过各种途径获得胚胎干细胞样的多能干细胞。其中Yamanaka等率先在体外通过病毒载体诱导的方式实现体细胞重新编程,由此得到诱导性多能干细胞。多种无遗传修饰的诱导方式正在尝试和改进中,例如用小分子化合物来代替外源基因进行重编程引起了很大的兴趣。用基于细胞水平的表型筛选法和信号通路筛选法,已筛选出特异小分子或天然产物,也可以特异地将成熟细胞去分化为干细胞,有望运用于组织修复和再生。而利用重组蛋白在体外将体细胞诱导为干细胞,也获得了初步成功。由诱导性多能干细胞在体外诱导分化出的细胞在治疗相应疾病方面展示出一定疗效。不同类型的干细胞向体细胞的定向分化策略都是基于目前对发育生物学的认识,这些研究揭示了一些共同的可能线索。     

Effects of culture conditions on estrogen-mediated hepatic in vitro gene expression and correlation to in vivo responses

Refinement of in vitro systems for predictive toxicology is important in order to develop high-throughput early toxicity screening assays and to minimize animal testing studies. This study assesses the ability of mouse Hepa-1c1c7 hepatoma cell model under differing culture conditions to predict in vivo estrogen-induced hepatic gene expression changes. Custom mouse cDNA microarrays were used to compare Hepa-1c1c7 temporal gene expression profiles treated with 10 nM 17beta-estradiol (E2) in serum-free and charcoal-stripped serum supplemented media at 1, 2, 4, 8, 12, and 24 h. Stripped serum supplemented media increased the number gene expression changes and overall responsiveness likely due to the presence of serum factors supporting proliferation and mitochondrial activity. Data from both experiments were compared to a gene expression time course study examining the hepatic effects of 100 microg/kg 17alpha-ethynyl estradiol (EE) in C57BL/6 mice at 2, 4, 8, 12, 18, and 24 h. Only 18 genes overlapped between the serum-free and in vivo studies, whereas 238 genes were in common between Hepa-1c1c7 cells in stripped serum data and C57BL/6 liver samples. Stripped serum cultured cells exhibited E2-elicited gene expression changes associated with proliferation, cytoskeletal re-organization, cholesterol uptake and synthesis, increased fatty acid beta-oxidation, and oxidative stress, which correlated with in vivo hepatic responses. These results demonstrate that E2 treatment of Hepa-1c1c7 cells in serum supplemented media modulate responses in selected pathways which appropriately model estrogen-elicited in vivo hepatic responses.     

Differentiation of embryonic stem cells for pharmacological studies on adipose cells.

The ongoing global explosion in the incidence of obesity has focused attention on the development of adipose cells. Severe obesity is the result of an increase in fat cell size in combination with increased fat cell number. New fat cells arise from a pre-existing pool of adipose stem cells that are present irrespective of age. The development of established preadipocyte cell lines has facilitated the study of different steps leading to terminal differentiation. However, these systems are limited for studying early events of differentiation as they represent cells which are already determined for the adipogenic lineage. In vitro differentiation of mouse embryonic stem (ES) cells towards the adipogenic lineage provides an alternative source of adipocytes for study in tissue culture and offers the possibility to investigate regulation of the first steps of adipose cell development. In this review, we describe the sequential requirement of retinoic acid and PPARgamma during adipogenesis in ES cells. Stimulation of ES cells with synthetic retinoids which are selective ligands of the retinoic acid receptor isotypes allowed the investigation of the contribution of the different retinoic receptors on the RA-dependent differentiation. The effects of thiazolidinediones, a new class of pharmacological agents used for the treatment of type 2 diabetes, and of statins, drugs used in therapy for lowering cholesterol, on the differentiation of ES cells into adipocytes or osteoblasts are described. Finally, we propose a model in which PPARgamma plays a key role in the decision of stem cells to undergo differentiation into adipocytes or osteoblasts, two closely related lineages.