间充质干细胞双标记光学成像的体内试验研究

目的:验证双标记生物发光成像活体观测MSCs在肝癌裸鼠模型向肿瘤病灶的趋化作用的可行性。方法:应用fluorescence(荧光)与bioluminescence(生物发光)两种成像方法,对MSCs进行CM-Di I荧光标记及对人肝癌细胞Hep G2进行Fluc-慢病毒感染并由此建立裸鼠肝癌模型,构建双标记成像系统,应用精诺真小动物光学成像仪在裸鼠肝癌模型中观测间充质干细胞向肿瘤的趋化作用。结果:在鼠尾静脉注射标记MSCs细胞后21天荧光成像可见MSCs主要积聚于肿瘤病灶处及肝脏。生物发光成像后可监测到病灶处由luciferase标记肿瘤细胞(Hep G2)发出荧光;将荧光成像与生物发光成像所得图像经后处理融合后,可见证间充质干细胞像肿瘤病灶定向迁徙的生物过程。经肿瘤病理切片证实间充质干细胞成功迁徙至肿瘤病灶中。结论:应用间充质干细胞双标记光学成像系统实现MSCs在活体内对肿瘤的趋化过程进行观测是可行的。这种成像方法可作为下一步以MSCs为载体的肿瘤基因治疗的有效监测手段。     

活体动物体内光学成像技术的研究进展

生物发光和荧光成像作为近年来新兴的活体动物体内光学成像技术,以其操作简便及直观性成为研究小动物活体成像的一种理想方法,在生命科学研究中得以不断发展。利用这种成像技术,可以直接实时观察标记的基因及细胞在活体动物体内的活动及反应。利用光学标记的转基因动物模型可以研究疾病的发生发展过程,进行药物研究及筛选等。本文综述了现有活体动物体内光学成像技术的原理、应用领域及发展前景,比较了生物发光与几种荧光技术的不同特点和应用。     

造血干细胞的研究进展

干细胞研究是一门新兴的学科。经过50多年的努力,造血干细胞的研究已经成为当今生物医学领域中发展最快的领域。介绍了造血干细胞的来源、分离纯化和检测方法以及“可塑性”等方面的研究情况,并详细说明了一些主要的造血干细胞表面标志以及造血干细胞在干细胞移植、细胞治疗和基因治疗等方面的临床应用和前景。     

弹指六年，终迎凤归巢

2018年12月6日,中国科学院营养与健康研究所潘巍峻研究组在Nature杂志发表封面文章,高清解析了体内造血干细胞归巢的完整动态过程。该研究历时6年,在优化活体成像技术的基础上,整合遗传调控、活体荧光标记以及图形重构计算等方法建立了全新的可以完整解析体内造血干细胞归巢的研究体系、造血干细胞标记系统和造血干细胞长时程活体追踪方案,首次揭示了体内造血干细胞归巢微环境的独特结构。阳光总在风雨后,每一个成果的取得,其背后无不凝结着科研人员的辛劳和汗水。本文分享了潘巍峻研究组完成这项研究的科研历程,旨在与广大科研人员互励共勉,在科研道路上砥砺前行,勇攀科学高峰。     

军事医学科学院干细胞与再生医学研究回顾与展望

干细胞具有高度自我更新、增殖和多向分化潜能,因而成为再生医学的基础.作为中国干细胞研究与应用的＂先驱＂单位和优势单位之一,我院早期开展造血干细胞生物学性能、造血调控机制、造血干/祖细胞扩增和定向诱导分化的研究,取得了一系列重要成果.相继开展的造血干细胞移植等系列研究和应用也取得了突出的成绩.近年来,我院又系统开展了胚胎干细胞自我更新与干性维持机制、干细胞增殖分化调控、干细胞建系与建库技术造血发育调控与造血干细胞移植新策略、成体干细胞治疗、肿瘤干细胞筛选与鉴定、干细胞为种子细胞的三维组织构建、干细胞再生相关药物等多个领域的研究,并取得突出进展进一步我们将瞄准干细胞与再生医学的重大科学问题和关键技术,建立高水平的研究和应用基地,形成我院干细胞与再生医学研究开发的关键技术体系,研发系列具有自主知识产权的关键技术和产品,并培养优秀的科研团队,进入世界先进行列.     

活体生物发光成像技术及其在病毒感染研究中的应用

生物发光是动物活体光学成像技术之一,因其反应灵敏、操作简单、数据精确,而被广泛地应用于生命科学研究多个领域,观测活体动物体内病毒复制、肿瘤生长等生命过程.生物发光技术采用荧光素酶基因标记细胞或病毒,与外源注射的底物荧光素发生反应,在冷CCD成像系统下显像并进行数据记录、分析.本文简要介绍活体生物发光成像这一新技术的原理...     

造血干细胞全标记红色和绿色荧光转基因小鼠的筛选

目的对五种荧光转基因小鼠造血干细胞中的荧光标记细胞进行分析,筛选造血干细胞全标记红色和绿色荧光转基因小鼠,为造血干细胞分化机制体内示踪研究提供理想的动物模型。方法采用活体荧光影像系统对两种红色荧光转基因小鼠品系C57BL/6J-TgN（CAG-DsRed-1和CAG-DsRed-2）ZLFILAS和三种绿色荧光转基因小鼠品系C57BL/6J-TgN（CAG-EGFP-1、CAG-EGFP-2和CAG-EGFP-3）ZLFILAS的荧光标记进行比较;采用流式细胞术检测各转基因小鼠的骨髓lin（-）c-kit（＋）Sca-1＋（LSK）造血干细胞荧光标记细胞比率,根据标记比率筛选造血干细胞全标记红色和绿色荧光转基因小鼠。结果活体荧光影像分析表明转基因小鼠均系统性表达红色或绿色荧光。流式细胞术检测表明LSK造血干细胞中高度表达红色和绿色荧光,其中,C57BL/6J-TgN（CAG-DsRed-1）ZLFILAS和C57BL/6J-TgN（CAG-EGFP-1）ZLFILAS的造血干细胞全部为荧光标记细胞。结论筛选获得在造血干细胞中全标记的红色和绿色荧光转基因小鼠,可为造血干细胞体内研究提供有效示踪工具。     

小动物体内可见光三维成像技术研究进展

活体动物体内可见光成像是采用生物发光和荧光为标记物,利用灵敏的仪器来监控活体动物体内的细胞活动、蛋白表达情况和基因行为。近年来,可见光成像在生物医学的各个方面得到了广泛的应用。随着成像技术和检测仪器的不断发展,现已从平面二维成像逐渐发展为立体三维成像。三维成像技术在靶点的空间定位、与器官的关系,及绝对定量方面都有了很大的进展。本文就三维成像技术的原理、应用和发展前景进行了简要的综述。     

自发光学信号成像系统在生物成像中的发展与应用

自发光学信号成像系统是近年来比较新颖的一项用于活体生物的基因或细胞活动的微观检测的光学技术,具有直观、操作简便以及分辨率高的特点。该技术主要分为生物发光成像技术和荧光成像技术,目前主要用于测定活体动物体内的细胞以及分子的活动或变化情况。由于该技术能够对动物体内的微观形态的变化进行精确的捕捉,对于癌症、基因表达、肿瘤以及其他病变均具有较好的监测作用。在本文中,将就自发光学信号成像系统在生物成像中的发展与应用进行详细的阐述。     

绿色荧光转基因大鼠模型的建立

目的随着干细胞研究的推进,大鼠干细胞的研究日趋迫切。本研究旨在为活体荧光影像系统、干细胞归巢、细胞移植体内示踪研究,提供绿色荧光蛋白EGFP转基因大鼠模型。方法通过显微注射方式获得EGFP转基因大鼠,采用活体荧光影像系统、激光共聚焦显微镜,对EGFP转基因大鼠各个组织的荧光表达水平进行比较;采用流式细胞术检测转基因大鼠血液和骨髓细胞、骨髓干细胞的荧光标记率,筛选骨髓干细胞高效标记绿色荧光的转基因大鼠。结果建立了心脏、肝脏、肌肉、肺、胰腺、脑、膀胱、胃、肾脏、肠和脾脏组织中,系统性表达EGFP的SD-TgN（ACT-EGFP-1）ZLFILAS转基因大鼠;流式细胞术检测表明,该品系血液细胞绿色荧光标记率为94.4%,骨髓干细胞绿色荧光标记率为97.8%。结论建立了多组织系统性高表达绿色荧光,骨髓干细胞荧光标记率高达95%以上的转基因大鼠,为影像分析,造血干细胞的归巢等研究提供了大鼠模型。     

Optical bioluminescence imaging of human ES cell progeny in the rodent CNS

Pre-clinical efforts of grafting human embryonic stem cell (hESC)-derived neural precursors have been hampered by problems ranging from graft rejection to overgrowth and tumor formation. The ability to detect such potential complications sensitively and reliably in clinically relevant contexts will rest upon the implementation of suitable non-invasive imaging technologies for continuously probing graft survival, proliferation, and migration. Neural precursors were transduced ex vivo using a lentiviral-mediated gene delivery system expressing firefly D-luciferase, under the control of a cytomegalovirus promoter. Transduced cells revealed no loss of cellular morphology, proliferative capacity, or neural phenotype in vitro. As a novel approach to monitoring the fate of human grafts within the living brain, we adapted optical bioluminescence imaging to assess long-term graft viability in immunodeficient mouse models transplanted with genetically engineered human neural precursor cells. We additionally applied this technology to immunocompetent models for detecting and characterizing the time course of graft rejection. Using this strategy, we define statistically relevant imaging criteria that can predict graft rejection or overgrowth. In conclusion, our data suggest that optical bioluminescence imaging can serve as an essential tool for the development of hESC-based grafting strategies in the CNS.     

间充质干细胞的细胞成像技术比较与应用

间充质干细胞是一类具有强大增殖、多向分化潜能和免疫调节能力的多功能细胞,研究显示间充质干细胞移植可能治疗多种难治性疾病,例如帕金森病、脊髓损伤以及肿瘤等。但是,人们对移植后的细胞在宿主内的存活、分布、增殖、分化、免疫排斥反应以及成瘤特性等问题尚不清楚,所以许多疾病经过细胞移植治疗后的进展及转归情况仍难以获得确切的科学证据。而细胞成像技术(包括放射性核素成像、超声成像、磁共振成像以及光学成像)可以在体外或者体内实现对间充质干细胞实时、无创的示踪,在以间充质干细胞为研究基础的细胞移植治疗和细胞组织再生的医学领域里有着巨大的应用潜力。该文综述近十年来细胞成像技术应用于示踪间充质干细胞移植疗法的研究进展,旨在比较当下多种热门细胞成像技术的优劣,进而找寻更合适的干细胞示踪策略,为干细胞移植治疗的基础和临床研究提供进一步的理论证据支持和研究思路。     

Characterizing Organelles in Live Stem Cells Using Label-Free Optical Diffraction Tomography

Label-free optical diffraction tomography (ODT), an imaging technology that does not require fluorescent labeling or other pre-processing, can overcome the limitations of conventional cell imaging technologies, such as fluorescence and electron microscopy. In this study, we used ODT to characterize the cellular organelles of three different stem cells—namely, human liver derived stem cell, human umbilical cord matrix derived mesenchymal stem cell, and human induced pluripotent stem cell—based on their refractive index and volume of organelles. The physical property of each stem cell was compared with that of fibroblast. Based on our findings, the characteristic physical properties of specific stem cells can be quantitatively distinguished based on their refractive index and volume of cellular organelles. Altogether, the method employed herein could aid in the distinction of living stem cells from normal cells without the use of fluorescence or specific biomarkers.     

Illuminating the Regenerative Properties of Stem Cells In Vivo with Bioluminescence Imaging

Preclinical animal studies are essential to the development of safe and effective stem cell therapies. Bioluminescence imaging (BLI) is a powerful tool in animal studies that enables the real-time longitudinal monitoring of stem cells in vivo to elucidate their regenerative properties. This review describes the application of BLI in preclinical stem cell research to address critical challenges in producing successful stem cell therapeutics. These challenges include stem cell survival, proliferation, homing, stress response, and differentiation. The applications presented here utilize bioluminescence to investigate a variety of stem and progenitor cells in several different in vivo models of disease and implantation. An overview of luciferase reporters is provided, along with the advantages and disadvantages of BLI. Additionally, BLI is compared to other preclinical imaging modalities and potential future applications of this technology are discussed in emerging areas of stem cell research.     

Labelling of human adipose-derived stem cells for non-invasive in vivo cell tracking

Human adipose-derived stem cells (ASC) can be expanded in an undifferentiated state or differentiated along the osteogenic, chondrogenic, adipogenic, myogenic, endothelial and neurogenic lineage. To test their in vivo and in situ regenerative potential, their fate needs to be traced after application in suitable defect models. Non-invasive imaging systems allow for real time tracking of labelled cells in the living animal. We have evaluated a bioluminescence cell tracking approach to visualise ASC labelled with luciferase in the living animal. Two procedures have been tested to efficiently label human stem cells with a reporter gene (luciferase, green fluorescent protein), namely lipofection with Lipofectamine 2000 and electroporation with a Nucleofector device. With both lipofection and nucleofection protocols, we have reached transfection efficiencies up to 60%. Reporter gene expression was detectable for 3 weeks in vitro and did not interfere with the phenotype and the stem cell properties of the cells. By means of a highly sensitive CCD camera, we were able to achieve real time imaging of cell fate for at least 20 days after application (intravenous, intramuscular, intraperitoneal, subcutaneous) in nude mice. Moreover, we were able to influence cell mobility by choosing different modes of application such as enclosure in fibrin matrix. The optical imaging system with transient transfection is an elegant cell-tracking concept to follow survival and fate of human stem cells in small animals.     

Looking and listening to light: the evolution of whole-body photonic imaging

Optical imaging of live animals has grown into an important tool in biomedical research as advances in photonic technology and reporter strategies have led to widespread exploration of biological processes in vivo. Although much attention has been paid to microscopy, macroscopic imaging has allowed small-animal imaging with larger fields of view (from several millimeters to several centimeters depending on implementation). Photographic methods have been the mainstay for fluorescence and bioluminescence macroscopy in whole animals, but emphasis is shifting to photonic methods that use tomographic principles to noninvasively image optical contrast at depths of several millimeters to centimeters with high sensitivity and sub-millimeter to millimeter resolution. Recent theoretical and instrumentation advances allow the use of large data sets and multiple projections and offer practical systems for quantitative, three-dimensional whole-body images. For photonic imaging to fully realize its potential, however, further progress will be needed in refining optical inversion methods and data acquisition techniques.