The simulated microgravity enhances the differentiation of mesenchymal stem cells into neurons

Growing evidence shows that physical microenvironments and mechanical stresses, independent of soluble factors, help influence mesenchymal-stem-cell fate. rMSCs (rat mesenchymal stem cells) present spread, spindle shape when cultured in normal gravity (NG) while in simulated microgravity (SMG) they become unspread, round shape. Here we demonstrate that simulated microgravity can enhance the differentiation of mesenchymal stem cells into neurons, which might be a new strategy for the treatment of central nervous system diseases. rMSCs were cultured respectively in normal gravity and in a clinostat to simulate microgravity, followed with neuronal differentiated medium. The neuronal cells derived from rMSCs in SMG express higher microtubule-associated protein-2 (MAP-2), tyrosine hydroxylase (TH) and choline acetyltransferase (CHAT). Furthermore, as rMSCs are subjected to SMG, they excrete more neurotrophins like nerve growth factor (NGF), brain derived neurophic factor (BDNF) and ciliary neurotrophic factor (CNTF). Neuronal cells from SMG group generated more mature action potentials and displayed repetitive action potentials by comparison to cells from NG group. We conclude that simulated microgravity can enhance the differentiation of mesenchymal stem cells into neurons.     

间充质干细胞标记示踪方法研究进展

间充质干细胞（MSCs）具有很强的自我更新能力和多向分化潜能,现已成为组织修复的理想种子细胞和基因治疗的靶细胞。但MSCs移植入体内的标记和示踪是当今研究的热点和难点问题。目前常用的标记示踪技术按不同的标记分类有：荧光染料标记,分子细胞标记,影像学成像技术标记等。就这些标记示踪方法的优缺点加以综述。     

Second-harmonic generation microscopy for assessment of mesenchymal stem cell-seeded acellular dermal matrix in wound-healing

Direct intra-skin injection of mesenchymal stem cells (MSCs) and the use of biomaterial scaffolds for grafts are both promising approaches of skin wound repair, however they still cannot generate skin that completely resembles the natural skin structures. In this study, we combined these two approaches by using acellular dermal matrix (ADM) recellularized with MSCs to repair cutaneous wounds in a murine model and two-photon fluorescence (TPF) microscopy and second-harmonic generation (SHG) microscopy to assess the effects of this therapy on wound healing. Bone marrow-derived mesenchymal stem cells (BM-MSCs) were tagged with GFP and seeded into ADM (ADM-MSC) via MSC and ADM co-culture. ADM-MSC, ADM or saline was applied to murine excisional skin wounds and wound-healing was evaluated by histological examination on days 7, 14, 21 and TFP microscopy on days 1, 3, 5 and 21 post-treatment. ADM-MSC promoted healing significantly more than treatment with ADM or saline alone, as it led to substantial neovascularization and complete skin appendage regeneration. Furthermore, the SHG microscopic imaging technique proved to be a useful tool for monitoring changes in the collagen network at the wound site during the healing process and assessing the effects of different therapies.     

SM5-1-Conjugated PLA nanoparticles loaded with 5-fluorouracil for targeted hepatocellular carcinoma imaging and therapy

SM5-1 is a humanized mouse antibody which has a high binding specificity for a membrane protein of about 230 kDa overexpressed in hepatocellular carcinoma (HCC), melanoma and breast cancer. In this study, SM5-1-conjugated poly d, l (lactide-coglycolide) (PLA) PLA containing Cy7 (PLA-Cy7-SM5-1) was prepared to study the targeting specificity of the bioconjugate to HCC-LM3-fLuc cell. Then, SM5-1-conjugated PLA containing 5-fluorouracil (5-FU) (PLA-5FU-SM5-1) and PLA containing 5-FU (PLA-5FU) were prepared for treatment of subcutaneous HCC-LM3-fLuc tumor mice. The results showed that PLA-5FU-SM5-1, PLA-5FU and 5-FU induced a 45.07%, 23.56% and 19.05% tumor growth inhibition rate, respectively, on day 31 post-treatment as determined by bioluminescent intensity. In addition, in order to evaluate the antitumor efficacy of PLA-5FU-SM5-1, HCC-LM3-fLuc cells were injected into the liver to establish the experimental orthotopic liver tumor models. The experiments showed that PLA-5FU-SM5-1, PLA-5FU and 5-FU induced a 53.24%, 31.00%, and 18.11% tumor growth inhibition rate, respectively, on day 31 post-treatment determined by the bioluminescent intensity of the abdomen in tumor-bearing mice. Furthermore, we have calculated the three-dimensional location of the liver cancer in mice using a multilevel adaptive finite element algorithm based on bioluminescent intensity decay calibration. The reconstruction results demonstrated that PLA-5FU-SM5-1 inhibited the tumor rapid progression, which were consistent with the results of subcutaneous tumor mice experiments and in vitro cell experiment results.     

PDL2在人胎盘源间充质干细胞对外周血T细胞免疫调节中的作用

目的 研究程序性死亡配体2(programmed death ligand 2,PDL2)在人胎盘源间充质干细胞(human placenta mesenchymal stem cell,hPMSCs)对外周血T细胞活化、增殖及周期免疫调节中的作用.方法 RT-PCR、激光共聚焦(laser scanning confocal microscopy,LSCM)及流式细胞术(flow cytometry,FCM)检测PDL2在hPMSCs上的表达;应用PDL2 siRNA阻断PDL2在hPMSCs上的表达;密度梯度离心法分离纯化T细胞;FCM分析阻断PDL2后,hPMSCs对植物血凝素(PHA)刺激下T细胞活化及波佛脂(PMA)活化下T细胞增殖和周期的影响.结果 hPMSCs高表达PDL2分子,PDL2siRNA能有效阻断PDL2在hPMSCs上的表达;FCM分析结果显示,hPMSCs能够抑制CD69在T细胞上的表达,但阻断PDL2后,CD69的表达与未阻断组相比无明显变化;hPMSCs能够显著抑制PMA活化的T细胞的增殖,且阻断PDL2后,其增殖指数被进一步上调;与未阻断组相比,处于G0/G1期的T细胞数量明显减少,处于S期的细胞数量明显增加.结论 PDL2在hPMSCs上表达能够协同hPMSCs对外周血T细胞周期的抑制,进而抑制T细胞的增殖.     

力学因素在间充质干细胞构建功能性组织工程化软骨中的作用

间充质干细胞具有多向分化潜能,可定向分化为软骨组织,并且取材广泛、体外扩增能力强,是广泛应用于软骨组织工程的理想细胞之一。由于关节软骨具有重要的生物力学功能,需要强调和评估间充质干细胞构建组织工程化软骨组织的力学生物学性能。为更好地了解和认识修复软骨的诱导因素、信号通路与力学特性之间的关系,本文回顾了间充质干细胞在功能性软骨组织工程研究中的力学生物学研究进展,并论述了该领域内目前存在的问题及若干可供探索的途径和新方向。     

LaB6 nanoparticles with carbon-doped silica coating for fluorescence imaging and near-IR photothermal therapy of cancer cells

In this study, LaB₆ nanoparticles are used as a novel nanomaterial for near-infrared (NIR) photothermal therapy because they are cheaper than nanostructured gold, are easy to prepare and have an excellent NIR photothermal conversion property. Furthermore, the surface of LaB₆ nanoparticles is coated with a carbon-doped silica (C-SiO₂) shell to introduce a fluorescent property and improve stability and biocompatibility. The resulting LaB₆@C-SiO₂ nanoparticles retain the excellent NIR photothermal conversion property and exhibit a bright blue emission under UV irradiation or a green emission under visible irradiation. Using a HeLa cancer cell line, it is demonstrated that LaB₆@C-SiO₂ nanoparticles have no significant cytotoxicity, but their presence leads to remarkable cell death after NIR irradiation. In addition, from the observation of cellular uptake, the fluorescence labeling function of LaB₆@SiO₂ (LaB₆ core/SiO₂ shell) nanoparticles is also confirmed. These results suggest that LaB₆@C-SiO₂ nanoparticles may potentially serve as an efficient multifunctional nano-platform for simultaneous fluorescent imaging and NIR-triggered photothermal therapy of cancer cells.     

骨髓间充质干细胞向肝细胞转化的研究进展

骨髓间充质干细胞具有自我更新和多向分化潜能的特性,在体内特定的微环境中可向肝前体细胞及成熟肝细胞转化,明显改善肝功能;在体外通过肝细胞生长因子等诱导作用可转化为肝细胞样细胞,有望成为肝细胞移植或生物人工肝支持系统的新型种子细胞。就骨髓间充质干细胞向肝细胞的转化研究进行了阐述。     

Adipose tissue-derived mesenchymal stem cells are more potent suppressors of dendritic cells differentiation compared to bone marrow-derived mesenchymal stem cells

Both mesenchymal stem cells (MSCs) and dendritic cells (DCs) are engaged in the regulation of the immune response parallel to their numerous functions.The main objective of this study was to compare the effects of mesenchymal stem cells isolated from human adipose tissue or human bone marrow on the expression of specific cell surface markers as well as the secretion of some cytokines by monocyte-derived dendritic cells. The set of methods used includes cell cultures, magnetic beads isolation of cells, flow cytometry, ELISA and proteome profiler kit assays. The results obtained show that MSCs isolated from human adipose tissue are more potent immunomodulators of differentiation of human DCs in comparison to the bone marrow-derived MSCs. In both cases the percentages of CD14+ cells were increased in co-cultures of MSCs and DCs and at the same time down-regulated the expression of CD80, CD86 and CD83 as in all experiments the effect of adipose tissue MSCs was stronger. Similarly, the secretion of IL-10 by dendritic cells was up-regulated in co-cultures of MSCs and dendritic cells and the effect was stronger when adipose tissue-derived MSCs were used.Taken together all results presented reveal the higher potential of the adipose tissue-derived MSCs to inhibit the differentiation and expression of functionally important co-stimulatory molecules on the surface of monocyte-derived dendritic cells than the bone marrow-derived MSCs.     

Use of mesenchymal stem cells for cutaneous repair and skin substitute elaboration

Human mesenchymal stem cells (MSCs) are a heterogeneous population of fibroblast-like cells, which are present in different locations, including bone marrow, adipose tissue, extra-foetal tissues, gingiva and dermis. MSCs, which present multipotency capacities, important expansive potential and immunotolerance properties, remain an attractive tool for tissue repair and regenerative medicine. Currently, several studies and clinical trials highlight the use of MSCs in cutaneous repair underlining that their effects are essentially due to the numerous factors that they release. MSCs are also used in skin substitute development. In this study, we will first discuss the different sources of MSCs actually available. We will then present results showing that bone marrow-derived MSCs prepared according to Good Manufacturing Practices and included in a dermal equivalent are able to promote appropriate epidermis growth and differentiation. These data demonstrate that bone marrow-derived MSCs represent a satisfactory alternative to dermal fibroblasts in order to develop skin substitute. In addition, MSCs could provide a useful alternative to sustain epidermis development and to promote wound healing.     

间充质干细胞调节树突状细胞相关功能的研究进展

树突状细胞(DCs)作为体内最强大的抗原提呈细胞,是适应性免疫应答的始动者,在较多疾病的发生发展过程中起着重要作用.间充质干细胞(MSCs)是具有多向分化潜能的成体干细胞,由于其强大的自我修复、抑制炎症以及免疫调节作用已成为研究的热点.大量的研究表明MSCs能通过影响DCs的成熟及功能,达到缓解疾病的目的.通过对MSCs调节DCs功能调节的深入研究有望取得疾病治疗的新进展.     

Bone marrow stem cells and biological scaffold for bone repair in aging and disease

The loss of bone mass observed in aging enhances the risk of fractures. The process of bone repair in aging is slow and limited due to reduced activity of the osteoblasts. Bone marrow stem cells (MSCs) residing in the bone marrow are the progenitors for osteoblasts. The ability to enhance healing of bone defect in aging by MSCs can contribute in the prevention of the complications resulting from long-term immobilization that are especially fatal in old age. Our aim was to test the ability of MSCs inserted into a biological scaffold to enhance bone defect repair. Osteoprogenitor cells were selected from rat bone marrow stem cells cultured in DMEM medium supplemented with FCS, antibiotics, ascorbic acid, beta-glycerophosphate, and dexamethasone. The selected osteogenic subpopulation was identified by osteocalcin immunohistochemistry as well as Alizarin red S and von Kossa staining which are specific for bone matrix and mineral deposition. Committed osteoprogenitor cells cultured on the hydrogel scaffold were transplanted into the area of a rat tibia segmental bone defect and examined after 6 weeks. Radiology images revealed that 6 weeks post-implantaion, calcified material was present in the site of the defect, indicating new bone formation. It is concluded that committed osteogenic MSCs contained in a biocompatible scaffold can provide a promising surgical tool for enhancement of bone defect healing that will minimize the complications of bone repair in aging and disease.     

Molecular imaging applications for immunology

The use of multimodality molecular imaging has recently facilitated the study of molecular and cellular events in living subjects in a noninvasive and repetitive manner to improve the diagnostic capability of traditional assays. The noninvasive imaging modalities utilized for both small animal and human imaging include positron emission tomography (PET), single photon emission computed tomography (SPECT), magnetic resonance imaging (MRI), ultrasound, and computed tomography (CT). Techniques specific to small-animal imaging include bioluminescent imaging (BIm) and fluorescent imaging (FIm). Molecular imaging permits the study of events within cells, the examination of cell trafficking patterns that relate to inflammatory diseases and metastases, and the ability to rapidly screen new drug treatments for distribution and effectiveness. In this paper, we will review the current field of molecular imaging assays (especially those utilizing PET and BIm modalities) and examine how they might impact animal models and human disease in the field of clinical immunology.     

Selective inhibition of breast cancer stem cells by gold nanorods mediated plasmonic hyperthermia

Cancer stem cells (CSCs) have been identified in a variety of cancers and emerged as a new target for cancer therapy. CSCs are resistant to many current cancer treatments, including chemotherapy and radiation therapy. Therefore, eradication of this cell population is a primary objective in cancer therapy. Here, we report gold nanorods (AuNRs) mediated photothermal treatment can selectively eliminate CSCs in MCF-7 breast cancer cells. It significantly reduced the aldehyde dehydrogenase positive (ALDH⁺) cells subpopulation and the mammosphere formation ability of treated cells. Also, the gene expression of stem cell markers was decreased. Cellular uptake assay revealed that polyelectrolyte conjugated AuNRs could be internalized by CSCs much more and faster than non cancer stem cells (NCSCs), which might be the main reason for the selective elimination of CSCs. We further loaded salinomycin (SA), a CSCs inhibitor with polyelectrolyte conjugated AuNRs to get a synergistic CSCs inhibition. Enhanced inhibition of CSCs was obtained by NIR light triggered drug release and hyperthermia. This CSCs-targeted thermo-chemotherapy platform provides a new combinatorial strategy for efficient inhibition of CSCs, which is promising to improve cancer treatment and may overcome the chemoresistance and recurrence of cancer.     

临床研究用间充质干细胞的体外制备策略

目的探讨一种安全、有效并易于推广的临床研究用间充质干细胞的产业化制备策略。方法常规方法分离获得原代脐带间充质干细胞,P1~P3代以含小牛血清培养基进行稳定传代后,以无血清培养基对P4~P6代细胞继续培养和扩增,并以含血清培养基作为对照。倒置显微镜每天定时观察细胞生长状态,CCK-8法比较P4代和P6代细胞在两种培养基中的增殖能力,并对P4~P6代细胞的细胞裂解液和细胞培养上清中的牛血清白蛋白(BSA)残留量进行检测。结果对分离获得的原代脐带间充质干细胞进行传代培养,在含血清培养基中,P1~P3代细胞增殖能力稳定,以4×104/ml密度接种,3.5~4d可达到90%融合;细胞进入P6后,在无血清培养基培养条件下增殖能力与含血清培养基相近;BSA残留量检测结果显示,无血清培养基组中细胞的培养上清和细胞裂解液中残留的BSA量低于10ng/106细胞,满足《中国生物制品规程》对相关细胞治疗产品中BSA残留量的标准要求。结论含血清培养与无血清培养相结合的程序性培养扩增体系,可为临床提供数量充足、质量可控的间充质干细胞。     

兔骨髓间充质干细胞在Cytodex 3微载体悬浮培养系统中的贴附条件优化

骨髓间充质干细胞(Mesenchymal stem cells,MSCs)在组织工程及基因治疗中具有重要的应用价值,为实现MSCs体外动态扩增,本研究采用微载体培养技术,考察兔MSCs接种入Cytodex 3微载体悬浮培养系统后的贴附情况。在低速连续搅拌条件下,MSCs接种后8~12h贴附达到平衡,贴附率仅为16.7%±1.1%;采用间歇搅拌方式、50%培养体积接种、降低贴附期培养基中血清浓度均使MSCs贴附率有显著提高;在四种培养基体系中,MSCs在αMEM中的贴附率比DMEM中平均高39.8%。与常规条件相对照,采用优化后的接种方法,贴附率从26.6%提高到65.5%,细胞总体扩增倍数从2.01提高到4.50。本研究结果为实现MSCs在微载体悬浮培养系统中大量扩增奠定了基础。     

间充质干细胞培养中分化现象及c-fos表达研究

目的观察不同的培养基对间充质干细胞(MSC)体外自发分化的影响及c鄄fos的表达情况。方法以密度梯度离心法从SD大鼠骨髓中培养MSC,分别以L鄄DMEM、RPMI鄄1640与MSCGM作为培养基,观察对MSC在体外培养扩增的影响,流式细胞仪鉴定MSC,以免疫组化方法检测原癌基因c鄄fos的蛋白表达情况。结果MSCGM培养的MSC体外基本维持较均一的梭形,并能保持6代以上较少分化,而用L鄄DMEM和RPMI鄄1640培养,原代MSC形态基本较好,两代后开始大量分化。大部分MSC表达FOS蛋白。结论专用培养基对MSC体外培养中保持未分化状态很关键。FOS可能是MSC的增殖与分泌作用的胞内信号之一。     

Immunoregulatory function of mesenchymal stem cells

Mesenchymal stem cells (MSC) are a rare subset of stem cells residing in the bone marrow where they closely interact with hematopoietic stem cells and support their growth and differentiation. MSC can differentiate into multiple mesenchymal and non-mesenchymal lineages, providing a promising tool for tissue repair. In addition, MSC suppress many T cell, B cell and NK cell functions and may affect also dendritic cell activities. Due to their limited immunogenicity, MSC are poorly recognized by HLA-incompatible hosts. Based on these unique properties, MSC are currently under investigation for their possible use to treat immuno-mediated diseases. However, both their condition of immunoprivilege and their immunosuppressive function have recently been challenged when analyzed under particular experimental conditions. Thus, it is likely that MSC effects on the immune system may be deeply influenced not only by cell-to-cell interactions, but also by environmental factors shaping their phenotype and functions.