人脂肪干细胞复合胶原/壳聚糖支架在生物反应器中扩增的研究

研究表明脂肪组织是多潜能干细胞的又一新来源,脂肪组织来源的干细胞可被用于细胞治疗及组织工程。然而,传统的培养方法很难满足临床需求。为获得大量的脂肪干细胞以满足临床需求,现将脂肪干细胞接种到胶原/壳聚糖支架上,比较细胞在静态环境和在转瓶中动态扩增的情况。通过CCK-8检测细胞增殖情况;并分析葡萄糖和乳酸的代谢情况;14d后扫描电镜观察细胞在支架内的生长情况;流式细胞仪检测干细胞相关表面标记表达;RT-PCR检测干细胞相关转录因子的表达;并检测扩增后的干细胞的多向分化潜能。结果表明:在动态微环境中扩增14d后,与静态条件下相比,支架内的细胞具有更强的增殖活性和更好的多向分化潜能。所扩增的细胞能够保持原有干细胞的特性。结论:所设计的支架-转瓶培养系统是一个简便有效的扩增脂肪干细胞的方法。     

诱导多能干细胞重编程方法的优化及其在航天医学中的应用展望

近年来,通过外源导入特定的转录因子,将体细胞重编程为类似胚胎干细胞（ESCs）潜能的诱导多能干细胞（iPSCs）掀起了干细胞研究的又一热潮,然而重编程效率低和安全性等问题严重阻碍着其临床应用.太空环境对成体干细胞分化潜能的影响是航天员生理变化的因素之一,具有类似ESCs全能性的iPSCs将为发育生理学及再生医学研究带来全新的视角.综述了iPSCs的研究进展,重点阐述提高安全性和重编程效率的方法和应用研究现状,并探讨了其在航天医学领域中的应用前景.     

气升式环流中空纤维膜生物反应器内骨髓间充质千细胞的培养与扩增

骨髓间充质干细胞（MSCs）具有多向分化的潜能,是重要的组织工程“种子细胞”和理想的基因治疗靶细胞,但在骨髓中的含量非常少,需体外扩增才能满足临床需求。今将第四代MSCs与Ⅰ型胶原溶液混合后接种于中空纤维膜（HFMs）内,置37℃、5％CO2、饱和湿度的培养箱内1h后形成凝胶,然后将此HFMs接种至气升式环流生物反应器（ALB）内,进行MSCs的三维动态培养与扩增。实验过程中每24h取样测吸光度、计细胞数、绘制细胞生长曲线,测定细胞代谢参数,并对扩增的细胞进行流式细胞仪分析及多向诱导分化检测。结果表明;在气升式环流中空纤维膜生物反应器（ALHFMB）内,O2含量基本保持恒定;细胞代谢旺盛,MSCs扩增倍数明显增加,7d后扩增近16倍;扩增的细胞仍保持MSCs表型并具有较强的成骨、成软骨及成脂肪的多向分化能力。     

气升式环流中空纤维膜生物反应器内骨髓间充质干细胞的培养与扩增

骨髓间充质干细胞(MSCs)具有多向分化的潜能,是重要的组织工程"种子细胞"和理想的基因治疗靶细胞,但在骨髓中的含量非常少,需体外扩增才能满足临床需求.今将第四代MSCs与Ⅰ型胶原溶液混合后接种于中空纤维膜(HFMs)内,置37℃、5% CO2、饱和湿度的培养箱内1 h后形成凝胶,然后将此HFMs接种至气升式环流生物反应器(ALB)内,进行MSCs的三维动态培养与扩增.实验过程中每24 h取样测吸光度、计细胞数、绘制细胞生长曲线,测定细胞代谢参数,并对扩增的细胞进行流式细胞仪分析及多向诱导分化检测.结果表明:在气升式环流中空纤维膜生物反应器(ALHFMB)内,O2含量基本保持恒定;细胞代谢旺盛,MSCs扩增倍数明显增加,7 d后扩增近16倍;扩增的细胞仍保持MSCs表型并具有较强的成骨、成软骨及成脂肪的多向分化能力.     

脂肪干细胞的应用前景

脂肪干细胞是近年来新发现的成体干细胞。可分化为多种中胚层来源的细胞,如成骨细胞、肝细胞、软骨细胞、肌细胞、内皮细胞等。本文将对近年来脂肪干细胞的研究及其应用前景进行综述。     

干细胞分化为胰岛细胞的研究进展

糖尿病是以高血糖为代谢特征的严重影响人类健康的疾病。目前,糖尿病较理想的治疗方法是胰腺移植,但受供体缺乏和免疫排斥两方面的限制而不能普遍应用。干细胞由于具有自我更新和多分化潜能,其作为糖尿病细胞替代治疗的种子资源,已成为目前研究的热点。本文对近年来干细胞分化为胰岛细胞的研究进展作一综述。     

平滑肌干细胞研究进展

传统理论认为,动脉粥样硬化等心血管疾病中新生血管内膜中的平滑肌细胞来自损伤部位血管壁中膜的平滑肌细胞的迁移,如今这种理论受到了挑战,最近的研究表明,骨髓来源以及其它组织中具有多向分化能力的一些细胞也可以分化为平滑肌细胞从而参与心血管疾病的发生发展.本文根据国内外的研究成果,综述了平滑肌干细胞的研究进展.     

卵黄囊造血分化调控的研究进展

卵黄囊是哺乳动物发育过程中最早的造血器官,卵黄囊造血干细胞(YS-HSC)具有多向分化的潜能,可能是成年造血干细胞的来源。YS-HSC的增殖、分化受多种细胞因子和黏附分子等因素的影响,是一个涉及多基因调控的复杂过程。本文就卵黄囊造血及YS-HSC的增殖、分化及其调控机制的研究进展作一综述。     

Wnt信号通路与人类疾病相关性的研究进展

Wnt信号传导通路是一条广泛存在于多细胞生物体内且具有高度进化保守性的信号通路。该通路对细胞增殖、分化、凋亡、细胞极性及细胞的迁移和侵入产生影响,在多种器官的发育形成过程以及成体状态下病理生理过程中发挥重要作用。目前已有大量研究表明,Wnt信号通路的改变与肿瘤的形成和发生、退行性疾病的发展以及干细胞功能的改变密切相关。有更多新的研究表明,该通路与炎症发生、新生血管形成、免疫功能的维持以及创伤愈合和组织再生也有潜在性的联系。该通路正作为一个关键热点应用于上述各个领域的基础应用及药物开发研究中。本文在检索Pub Med上关于Wnt信号通路与人类疾病文献的基础上,从Wnt信号通路的组成及其与人类纤维化疾病、代谢综合征、眼部疾病、肿瘤和骨相关疾病等方面的相关性,阐明Wnt信号传导通路在细胞的增殖、分化、凋亡等过程中发挥的重要调节作用及对维持诸多器官的正常发育和形成所起的至关重要的作用。     

昆明小鼠骨髓体外培养及生长情况的探讨

通过对昆明小鼠骨髓间充质干细胞(Mscs)的体外培养,观察细胞在一个周期内的生长情况,并绘制细胞的生长曲线,以研究其生长周期特点.方法:体外分离、纯化并培养昆明小鼠Mscs及细胞计数和细胞生长曲线的绘制.结果:昆明小鼠Mscs的培养生长曲线显示,Mscs在体外培养条件下生长经历了生长缓滞期、对数增生期和生长平稳期.结论:骨髓间充质干细胞具有高度的自我更新和多相分化潜能,具有独特的细胞增生分裂模式,使外源基因易于导入和表达,而使其成为潜在的基因治疗靶细胞,是细胞治疗的基础.     

A Molecular Analysis of Cytokine Content across Extracellular Vesicles,Secretions, and Intracellular Space from Different Site-Specific Adipose-Derived Stem Cells

Cytokines are multifunctional small proteins that have a vital influence on inflammatory states of tissues and play a role in signalling and cellular control mechanisms. Cytokine expression has primarily been viewed as a form of direct secretion of molecules through an active transportation; however, other forms of active transport such as extracellular vesicles are at play. This is particularly important in stem cells where signalling molecules are key to communication managing the levels of proliferation, migration, and differentiation into mature cells. This study investigated cytokines from intracellular content, direct cellular secretions, and extracellular vesicles from adult adipose-derived stem cells isolated from three distinct anatomical locations: abdomen, thigh, and chin. The cells were cultured investigated using live cell microscopy, cytokine assays, and bioinformatics analysis. The cytokines quantified and examined from each sample type showed a distinct difference between niche areas and sample types. The varying levels of TNF-alpha, IL-6 and IL-8 cytokines were shown to play a crucial role in signalling pathways such as MAPK, ERK1/2 and JAK-STAT in cells. On the other hand, the chemotactic cytokines IL-1rn, Eotaxin, IP-10 and MCP-1 showed the most prominent changes across extracellular vesicles with roles in noncanonical signalling. By examining the local and tangential roles of cytokines in stem cells, their roles in signalling and in regenerative mechanisms may be further understood.     

Hematopoiesis during Ontogenesis,Adult Life,and Aging

In the bone marrow of vertebrates, two types of stem cells coexist—hematopoietic stem cells (HSCs) and mesenchymal stem cells (MSCs). Hematopoiesis only occurs when these two stem cell types and their descendants interact. The descendants of HSCs supply the body with all the mature blood cells, while MSCs give rise to stromal cells that form a niche for HSCs and regulate the process of hematopoiesis. The studies of hematopoiesis were initially based on morphological observations, later extended by the use of physiological methods, and were subsequently augmented by massive application of sophisticated molecular techniques. The combination of these methods produced a wealth of new data on the organization and functional features of hematopoiesis in the ontogenesis of mammals and humans. This review summarizes the current views on hematopoiesis in mice and humans, discusses the development of blood elements and hematopoiesis in the embryo, and describes how the hematopoietic system works in the adult organism and how it changes during aging.     

The Role of Tumor Microenvironment in Regulating the Plasticity of Osteosarcoma Cells

Osteosarcoma (OS) is a malignancy that is becoming increasingly common in adolescents. OS stem cells (OSCs) form a dynamic subset of OS cells that are responsible for malignant progression and chemoradiotherapy resistance. The unique properties of OSCs, including self-renewal, multilineage differentiation and metastatic potential, 149 depend closely on their tumor microenvironment. In recent years, the likelihood of its dynamic plasticity has been extensively studied. Importantly, the tumor microenvironment appears to act as the main regulatory component of OS cell plasticity. For these reasons aforementioned, novel strategies for OS treatment focusing on modulating OS cell plasticity and the possibility of modulating the composition of the tumor microenvironment are currently being explored. In this paper, we review recent studies describing the phenomenon of OSCs and factors known to influence phenotypic plasticity. The microenvironment, which can regulate OSC plasticity, has great potential for clinical exploitation and provides different perspectives for drug and treatment design for OS.     

Fractone Stem Cell Niche Components Provide Intuitive Clues in the Design of New Therapeutic Procedures/Biomatrices for Neural Repair

The aim of this study was to illustrate recent developments in neural repair utilizing hyaluronan as a carrier of olfactory bulb stem cells and in new bioscaffolds to promote neural repair. Hyaluronan interacts with brain hyalectan proteoglycans in protective structures around neurons in perineuronal nets, which also have roles in the synaptic plasticity and development of neuronal cognitive properties. Specialist stem cell niches termed fractones located in the sub-ventricular and sub-granular regions of the dentate gyrus of the hippocampus migrate to the olfactory bulb, which acts as a reserve of neuroprogenitor cells in the adult brain. The extracellular matrix associated with the fractone stem cell niche contains hyaluronan, perlecan and laminin α5, which regulate the quiescent recycling of stem cells and also provide a means of escaping to undergo the proliferation and differentiation to a pluripotent migratory progenitor cell type that can participate in repair processes in neural tissues. Significant improvement in the repair of spinal cord injury and brain trauma has been reported using this approach. FGF-2 sequestered by perlecan in the neuroprogenitor niche environment aids in these processes. Therapeutic procedures have been developed using olfactory ensheathing stem cells and hyaluronan as a carrier to promote neural repair processes. Now that recombinant perlecan domain I and domain V are available, strategies may also be expected in the near future using these to further promote neural repair strategies.     

Stem Cell and Macrophage Roles in Skeletal Muscle Regenerative Medicine

In severe muscle injury, skeletal muscle tissue structure and functionality can be repaired through the involvement of several cell types, such as muscle stem cells, and innate immune responses. However, the exact mechanisms behind muscle tissue regeneration, homeostasis, and plasticity are still under investigation, and the discovery of pathways and cell types involved in muscle repair can open the way for novel therapeutic approaches, such as cell-based therapies involving stem cells and peripheral blood mononucleate cells. Indeed, peripheral cell infusions are a new therapy for muscle healing, likely because autologous peripheral blood infusion at the site of injury might enhance innate immune responses, especially those driven by macrophages. In this review, we summarize current knowledge on functions of stem cells and macrophages in skeletal muscle repairs and their roles as components of a promising cell-based therapies for muscle repair and regeneration.     

Epidermal Stem Cells and Their Epigenetic Regulation

Stem cells play an essential role in embryonic development, cell differentiation and tissue regeneration. Tissue homeostasis in adults is maintained by adult stem cells resident in the niches of different tissues. As one kind of adult stem cell, epidermal stem cells have the potential to generate diversified types of progeny cells in the skin. Although its biology is still largely unclarified, epidermal stem cells are widely used in stem cell research and regenerative medicine given its easy accessibility and pluripotency. Despite the same genome, cells within an organism have different fates due to the epigenetic regulation of gene expression. In this review, we will briefly discuss the current understanding of epigenetic modulation in epidermal stem cells.     

Oncogenes,Proto-Oncogenes,and Lineage Restriction of Cancer Stem Cells

In principle, an oncogene is a cellular gene (proto-oncogene) that is dysfunctional, due to mutation and fusion with another gene or overexpression. Generally, oncogenes are viewed as deregulating cell proliferation or suppressing apoptosis in driving cancer. The cancer stem cell theory states that most, if not all, cancers are a hierarchy of cells that arises from a transformed tissue-specific stem cell. These normal counterparts generate various cell types of a tissue, which adds a new dimension to how oncogenes might lead to the anarchic behavior of cancer cells. It is that stem cells, such as hematopoietic stem cells, replenish mature cell types to meet the demands of an organism. Some oncogenes appear to deregulate this homeostatic process by restricting leukemia stem cells to a single cell lineage. This review examines whether cancer is a legacy of stem cells that lose their inherent versatility, the extent that proto-oncogenes play a role in cell lineage determination, and the role that epigenetic events play in regulating cell fate and tumorigenesis.     

Lessons Learned about Human Stem Cell Responses to Ionizing Radiation Exposures: A Long Road Still Ahead of Us

Human stem cells (hSC) possess several distinct characteristics that set them apart from other cell types. First, hSC are self-renewing, capable of undergoing both asymmetric and symmetric cell divisions. Second, these cells can be coaxed to differentiate into various specialized cell types and, as such, hold great promise for regenerative medicine. Recent progresses in hSC biology fostered the characterization of the responses of hSC to genotoxic stresses, including ionizing radiation (IR). Here, we examine how different types of hSC respond to IR, with a special emphasis on their radiosensitivity, cell cycle, signaling networks, DNA damage response (DDR) and DNA repair. We show that human embryonic stem cells (hESCs) possess unique characteristics in how they react to IR that clearly distinguish these cells from all adult hSC studied thus far. On the other hand, a manifestation of radiation injuries/toxicity in human bodies may depend to a large extent on hSC populating corresponding tissues, such as human mesenchymal stem cells (hMSC), human hematopoietic stem cells (hHSC), neural hSC, intestine hSC, etc. We discuss here that hSC responses to IR differ notably across many types of hSC which may represent the distinct roles these cells play in development, regeneration and/or maintenance of homeostasis.     

Inhibition of Cdk5 in PV Neurons Reactivates Experience-Dependent Plasticity in Adult Visual Cortex

Cyclin-dependent kinase 5 (Cdk5) has been shown to play a critical role in brain development, learning, memory and neural processing in general. Cdk5 is widely distributed in many neuron types in the central nervous system, while its cell-specific role is largely unknown. Our previous study showed that Cdk5 inhibition restored ocular dominance (OD) plasticity in adulthood. In this study, we specifically knocked down Cdk5 in different types of neurons in the visual cortex and examined OD plasticity by optical imaging of intrinsic signals. Downregulation of Cdk5 in parvalbumin-expressing (PV) inhibitory neurons, but not other neurons, reactivated adult mouse visual cortical plasticity. Cdk5 knockdown in PV neurons reduced the evoked firing rate, which was accompanied by an increment in the threshold current for the generation of a single action potential (AP) and hyperpolarization of the resting membrane potential. Moreover, chemogenetic activation of PV neurons in the visual cortex can attenuate the restoration of OD plasticity by Cdk5 inhibition. Taken together, our results suggest that Cdk5 in PV interneurons may play a role in modulating the excitation and inhibition balance to control the plasticity of the visual cortex.