低温冻存对骨髓基质细胞生物学特性的影响

目的：探讨低温冻存对骨髓细胞和贴壁基质细胞生物学特性的影响。方法：取新鲜骨髓和经Dexter法培养14d的骨髓贴壁基质细胞(称“基质细胞”),经-196℃液氮冻存(前者称“冻存骨髓”,后者称“冻存基质细胞”)2周,复温,再用Dexter法培养这些细胞,检测细胞增殖、细胞形态、细胞化学染色、细胞表面抗原及基质细胞支持另一骨髓造血细胞形成的鹅卵石造血区(CAFC),长期培养起始细胞(LTCIC)的变化,比较冻存对骨髓细胞和基质细胞生物学特性的影响。结果：生长特性：冻存骨髓比新鲜骨髓、冻存基质细胞比新鲜基质细胞培养后融合成片的时间延迟,细胞增殖数比也有减低。细胞成分：冻存骨髓比新鲜骨髓形成的成纤维细胞、内皮细胞比率下降,而巨噬细胞和脂肪细胞比率升高,冻存基质细胞上述现象更明显：冻存后含凋亡小体的细胞在骨髓细胞和基质细胞内均有增加。细胞表面抗原：冻存骨髓、冻存基质细胞CD14、HLA-DR抗原表达百分率比新鲜骨髓、新鲜基质细胞高,CD45、CD33反之。支持造血：冻存前后骨髓和基质细胞支持形成的CAFC和LTC-IC,生长良好,无显著差异。结论：骨髓细胞和经培养生成的贴壁基质细胞,经冻存和复温,生物学特性有一定变化,但仍可以保留良好的支持造血重建功能。     

The pro-metastatic role of bone marrow-derived cells: a focus on MSCs and regulatory T cells

Several bone marrow-derived cells have been shown to promote tumour growth and progression. These cells can home to the primary tumour and become active components of the tumour microenvironment. Recent studies have also identified bone marrow-derived cells—such as mesenchymal stem cells and regulatory T cells—as contributors to cancer metastasis. The innate versatility of these cells provides diverse functional aid to promote malignancy, ranging from structural support to signal-mediated suppression of the host immune response. Here, we review the role of mesenchymal stem cells and regulatory T cells in cancer metastasis. A better understanding of the bipolar nature of these bone marrow-derived cells in physiological and malignant contexts could pave the way for new therapeutics against metastatic disease.     

Inflammatory T cells rapidly induce differentiation of human bone marrow stromal cells into mature osteoblasts

Activated T cells secrete multiple osteoclastogenic cytokines which play a major role in the bone destruction associated with rheumatoid arthritis. While the role of T cells in osteoclastogenesis has received much attention recently, the effect of T cells on osteoblast formation and activity is poorly defined. In this study, we investigated the hypothesis that in chronic inflammation activated T cells contribute to enhanced bone turnover by promoting osteoblastic differentiation. We show that T cells produce soluble factors that induce alkaline phosphatase activity in bone marrow stromal cells and elevated expression of mRNA for Runx2 and osteocalcin. This data indicate that T cell derived factors have the capacity to stimulate the differentiation of bone marrow stromal cells into the osteoblast phenotype. RANKL mRNA was undetectable under any conditions in highly purified bone marrow stromal cells. In contrast, RANKL was constitutively expressed in primary osteoblasts and only moderately up-regulated by activated T cell conditioned medium. Interestingly, both bone marrow stromal cells and osteoblasts expressed mRNA for RANK, which was strongly up-regulated in both cell types by activated T cell conditioned medium. Although, mRNA for the RANKL decoy receptor, osteoprotegerin, was also up-regulated by activated T cell conditioned medium, it's inhibitory effects may be mitigated by a simultaneous rise in the osteoprotegerin competitor TNF-related apoptosis-inducing ligand. Based on our data we propose that during chronic inflammation, T cells regulate bone loss by a dual mechanism involving both direct stimulation of osteoclastogenesis, by production of osteoclastogenic cytokines, and indirectly by induction of osteoblast differentiation and up-regulation of bone turnover via coupling.     

Bone marrow mesenchymal stem cells

Following the identification of bone marrow multipotent cells that could adhere to plastic and differentiate along numerous mesenchymal lineages in vitro, a considerable effort has been invested in characterizing and expanding these cells, which are now called “mesenchymal stem cells” (MSCs), in vitro. Over the years, numerous lines of evidence have been provided in support of their plasticity, their extraordinary immunomodulatory properties, their potential use for tissue engineering purposes, as well as their ability to be recruited to sites of injury, where they might contribute a “natural in vivo system for tissue repair.” Moreover, some studies have attempted the characterization of their cell‐surface specific antigens and of their anatomical location in vivo. Lastly, it has been shown that similar cells could be also isolated from organs other than the bone marrow. Despite this impressive body of investigations, numerous questions related to the developmental origin of these cells, their proposed pluripotency, and their role in bone modeling and remodeling and tissue repair in vivo are still largely unanswered. In addition, both a systematic phenotypic in vivo characterization of the MSC population and the development of a reproducible and faithful in vivo assay that would test the ability of MSCs to self‐renew, proliferate, and differentiate in vivo are just beginning. This brief review summarizes the current knowledge in the field of study of MSCs and the outstanding questions. J. Cell. Biochem. 109: 277–282, 2010. © 2009 Wiley‐Liss, Inc.     

Adenovirus-mediated BMP2 expression in human bone marrow stromal cells

Recombinant adenoviral vectors have been shown to be potential new tools for a variety of musculoskeletal defects. Much emphasis in the field of orthopedic research has been placed on developing systems for the production of bone. This study aims to determine the necessary conditions for sustained production of high levels of active bone morphogenetic protein 2 (BMP2) using a recombinant adenovirus type 5 (Ad5BMP2) capable of eliciting BMP2 synthesis upon infection and to evaluate the consequences for osteoprogenitor cells. The results indicate that high levels (144 ng/ml) of BMP2 can be produced in non-osteoprogenitor cells (A549 cell line) by this method and the resultant protein appears to be three times more biologically active than the recombinant protein. Surprisingly, similar levels of BMP2 expression could not be achieved after transduction with Ad5BMP2 of either human bone marrow stromal cells or the mouse bone marrow stromal cell line W20-17. However, human bone marrow stromal cells cultured with 1 microM dexamethasone for four days, or further stimulated to become osteoblast-like cells with 50 microg/ml ascorbic acid, produced high levels of BMP2 upon Ad5BMP2 infection as compared to the undifferentiated cells. The increased production of BMP2 in adenovirus transduced cells following exposure to 1 microM dexamethasone was reduced if the cells were not given 50 microg/ml ascorbic acid. When bone marrow stromal cells were allowed to become confluent in culture prior to differentiation, BMP2 production in response to Ad5BMP2 infection was lost entirely. Furthermore, the increase in BMP2 synthesis seen during differentiation was greatly decreased when Ad5BMP2 was administered prior to dexamethasone treatment. In short, the efficiency of adenovirus mediated expression of BMP2 in bone marrow stromal cells appears to be dependent on the differentiation state of these cells.     

Bone marrow‐derived cells can acquire cardiac stem cells properties in damaged heart

Experimental data suggest that cell‐based therapies may be useful for cardiac regeneration following ischaemic heart disease. Bone marrow (BM) cells have been reported to contribute to tissue repair after myocardial infarction (MI) by a variety of humoural and cellular mechanisms. However, there is no direct evidence, so far, that BM cells can generate cardiac stem cells (CSCs). To investigate whether BM cells contribute to repopulate the Kit⁺ CSCs pool, we transplanted BM cells from transgenic mice, expressing green fluorescent protein under the control of Kit regulatory elements, into wild‐type irradiated recipients. Following haematological reconstitution and MI, CSCs were cultured from cardiac explants to generate ‘cardiospheres’, a microtissue normally originating in vitro from CSCs. These were all green fluorescent (i.e. BM derived) and contained cells capable of initiating differentiation into cells expressing the cardiac marker Nkx2.5. These findings indicate that, at least in conditions of local acute cardiac damage, BM cells can home into the heart and give rise to cells that share properties of resident Kit⁺ CSCs.     

In vitro chondrogenesis of human synovium-derived mesenchymal stem cells: optimal condition and comparison with bone marrow-derived cells

There are increasing reports that mesenchymal stem cells (MSCs) are present in various tissues other than bone marrow, including synovium. Here we investigated the optimal conditions for in vitro chondrogenesis of human synovium-derived MSCs and compared these cells with bone marrow-derived MSCs, especially in terms of their chondrogenesis potential. Synovium and bone marrow were harvested from six donors during knee operations for ligament injuries. Digested synovium cells or nucleated cells from bone marrow were expanded clonally. A pellet culture system was used for chondrogenesis, and the best combination of up to three cytokines of the seven assessed. Synovium-derived MSCs plated at a lower density expanded more rapidly. Contrary to previous reports, a combination of TGFbeta and dexamethasone was not sufficient to induce chondrogenesis. However, addition of BMP2 to TGFbeta and dexamethasone dramatically increased cartilage pellet size and the synthesis of cartilage matrix. The cartilage pellets were also analyzed by electron microscopy and immunohistology. DNA content per pellet decreased during chondrogenesis, indicating the pellet increased its size through the accumulation of newly synthesized extracellular matrix. Sequential chondrogenic gene expression was demonstrated by RT-PCR. Synovium-derived MSCs looked similar to the bone marrow-derived MSCs in their surface epitopes and proliferation potential; however, cartilage pellets from synovium were significantly larger than those from bone marrow in patient-matched comparisons. We demonstrated that the combination of TGFbeta, dexamethasone, and BMP2 was optimal for in vitro chondrogenesis of synovium-derived MSCs and that the synovium-derived MSCs have a greater chondrogenesis potential than bone marrow-derived MSCs.     

Evaluation of bone-derived and marrow-derived vascular endothelial cells by microarray analysis

This study focused on the differential expression levels of proteins that may exist between bone-derived and marrow-derived vascular endothelial cells (BVEC and MVEC). The vascular cells were isolated from trabecular bone regions and central marrow cavity regions of mouse long bones. Cells were cultured for 1 week to expand the population then separated from non-vascular cells using biotinylated isolectin B4, streptavidin-coated metallic microbeads, and a magnetic column. After an additional week of culture time, RNA was isolated from both cell types and compared using microarray analysis. RT-PCR was used to confirm and relatively quantitate the RNA messages. The bone-derived cells expressed more aldehyde dehydrogenase 3A1 (ALDH3A1), Secreted Modular Calcium-2 (SMOC-2), CCAAT enhancer binding protein (C/EBP-beta), matrix metalloproteinase 13 (MMP-13), and annexin 8 (ANX8) than the marrow-derived cells. Spalpha and matrix GLA-protein (MGP) were produced in greater abundance by the marrow-derived cells. This study reveals that there are profound and unique differences between the vasculature of the metaphysis as compared to that of the central marrow cavity. The unique array of proteins expressed by the bone-derived endothelial cells may support growth of tumors from cancer cells that frequently metastasize and lodge in the trabecular bone regions.     

Liver stem cells

The capacity of hepatocytes and cholangiocytes to contribute to their own maintenance has long been recognized. More recently, studies have indicated the presence of both intra-hepatic and extra-hepatic stem/progenitor cell populations. The intraorgan compartment probably derives primarily from the biliary tree, most particularly the most proximal branches, i.e. the canals of Hering and smallest ductules. The extra-organ compartment is at least in part derived from diverse populations of cells from the bone marrow. These three tiers of liver cell regeneration serve to maintain the normal organ and to regenerate damaged parenchyma in response to a variety of insults. The nature and extent of the insult determines the balance between these stem/progenitor compartments. This revised version was published online in July 2006 with corrections to the Cover Date.     

孕期应激对子代大鼠骨髓淋巴干细胞发育的影响

孕期应激对子代产生的影响是多方面的,这种影响是复杂的。研究表明,出生前的应激经历可导致出生后子代长期的免疫功能改变。这些改变追其根源与骨髓淋巴干细胞的改变有关。本文综述了大鼠孕期经历应激的子代骨髓淋巴干细胞所受的影响及免疫系统的相关改变,并根据现有的研究提出假说,为进一步研究孕期应激导致子代免疫系统改变的机理研究提供新的思路。     

Proteomic profiling of distinct clonal populations of bone marrow mesenchymal stem cells

Mesenchymal stem cells (MSCs) have attracted immense research interest in the field of regenerative medicine due to their ability to be cultured for successive passages and multi‐lineage differentiation. The molecular mechanisms governing MSC self‐renewal and differentiation remain largely unknown. The development of sophisticated techniques, in particular clinical proteomics, has enabled researchers in various fields to identify and characterize cell specific biomarkers for therapeutic purposes. This study seeks to understand the cellular and sub‐cellular processes responsible for the existence of stem cell populations in bone marrow samples by revealing the whole cell proteome of the clonal cultures of bone marrow‐derived MSCs (BMSCs). Protein profiling of the MSC clonal populations was conducted by Two‐Dimensional Liquid Chromatography/Matrix‐Assisted Laser Desorption/Ionisation (MALDI) Mass Spectrometry (MS). A total of 83 proteins were identified with high confidence of which 11 showed differential expression between subpopulations, which included cytoskeletal and structural proteins, calcium binding proteins, cytokinetic proteins, and members of the intermediate filament family. This study generated a proteome reference map of BMSCs from the clonal populations, which will be valuable to better understand the underlying mechanism of BMSC self‐renewal and differentiation. J. Cell. Biochem. 106: 776–786, 2009. © 2009 Wiley‐Liss, Inc.     

Identification of primitive hematopoietic progenitor cells in the rhesus macaque

The close phylogenetic relationship of macaques to humans has resulted in their widespread use as a preclinical model for bone marrow transplantation and stem cell gene therapy. To facilitate further use of this model, we undertook analysis of hematopoietic cells using multiparametric flow cytometric analysis. Rhesus CD34+CD38- cells displayed a number of characteristics of primitive hematopoietic cells, including low forward and orthogonal scatter and the lack of expression of lineage-specific markers or human lymphocyte antigen-DR. Four-color flow cytometric analysis demonstrated that rhesus CD34+CD38- cells were heterogenous with respect to Thy-1 expression and were CD59dim. Quantitative limiting dilution long-term culture-initiating cell (LTC-IC) analysis demonstrated that CD34+CD38- cells were approximately 150-fold enriched for LTC-IC as compared with unfractionated bone marrow, and occurred at a frequency similar to that previously reported in humans. Thus, as in humans, the CD34+38- population of rhesus macaque bone marrow is enriched for primitive, multipotent hematopoietic progenitor cells.     

Epigenetic modifiers promote efficient generation of neural-like cells from bone marrow-derived mesenchymal cells grown in neural environment

Understanding mechanisms that govern cell fate decisions will lead to developing techniques for induction of adult stem cell differentiation to desired cell outcomes and, thus, production of an autologos source of cells for regenerative medicine. Recently, we demonstrated that stem cells derived from adult central nervous system or bone marrow grown with other cell lineages or with more undifferentiated cells sometimes take on those characteristics. This indicates that manipulating extracellular factors may be sufficient to alter some developmental restrictions regulated by the epigenetic system. In this study, using pharmacological agents that interfere with the main components of the epigenetic program such as DNA methylation and histone deacetylation, we induce high-level expression of embryonic and neural stem cell (NSC) marker Sox2 in bone marrow-derived mesenchymal stem cells (MSCs). Exposure of these modified cells to a neural environment via juxtacrine and paracrine interactions promote efficient generation of neural stem-like cells as well as cells with neuronal and glial characteristics. We concluded that the manipulation strategy used in this study can be a useful method for efficient production of NSC-like cells from MSCs.     

Effect of BMP4 preceded by retinoic acid and co‐culturing ovarian somatic cells on differentiation of mouse embryonic stem cells into oocyte‐like cells

Bone morphogenetic protein 4 (BMP4) and retinoic acid (RA) signaling are the key regulators for germ cell and meiosis induction, respectively. Gonadal tissue also provides an appropriate microenvironment for oocyte differentiation in vivo. The current study aimed to determine whether mimicking in vivo niche is more efficient for oocyte differentiation from embryonic stem (ES) cells. Here, differentiation of mouse ES cells toward oocyte‐like cells using embryoid body (EB) and monolayer protocols was induced in the presence (+BMP4) or absence (‐BMP4) of BMP4. On day 5, each group was co‐cultured with ovarian somatic cells in the presence or absence of RA (+RA or –RA) for an additional 14 days. Our results showed a significant increase in expression of meiotic markers in the +BMP4 condition in EB differentiation protocol. Further differentiation with ovarian somatic cells led to a subpopulation of oocyte‐like cell formation. Compared to the controls, the +RA condition resulted in a significant elevation of the meiotic gene expression in contrast to Oct4 that significantly decreased in both protocols. In the cells pre‐treated with BMP4 and then exposed to RA in the monolayer differentiation protocol, the gene expression levels of germ cell, Mvh, and maturation markers, Cx37, Zp2, and Gdf9, were also upregulated significantly. Therefore, it can be concluded that +BMP4 and +RA along with ovarian somatic cell co‐culture improved the rate of in vitro oocyte differentiation.     

孕期应激对子代大鼠骨髓淋巴干细胞发育的影响

孕期应激对子代产生的影响是多方面的,这种影响是复杂的。研究表明,出生前的应激经历可导致出生后子代长期的免疫功能改变。这些改变追其根源与骨髓淋巴干细胞的改变有关。本文综述了大鼠孕期经历应激的子代骨髓淋巴干细胞所受的影响及免疫系统的相关改变,并根据现有的研究提出假说,为进一步研究孕期应激导致子代免疫系统改变的机理研究提供新的思路。     

Myocardial regeneration with bone-marrow-derived stem cells

Despite significant therapeutic advances, heart failure remains the predominant cause of mortality in the Western world. Ischaemic cardiomyopathy and myocardial infarction are typified by the irreversible loss of cardiac muscle (cardiomyocytes) and vasculature composed of endothelial cells and smooth muscle cells, which are essential for maintaining cardiac integrity and function. The recent identification of adult and embryonic stem cells has triggered attempts to directly repopulate these tissues by stem cell transplantation as a novel therapeutic option. Reports describing provocative and hopeful examples of myocardial regeneration with adult bone-marrow-derived stem and progenitor cells have increased the enthusiasm for the use of these cells, yet many questions remain regarding their therapeutic potential and the mechanisms responsible for the observed therapeutic effects. In this review article we discuss the current preclinical and clinical advances in bone-marrow-derived stem or progenitor cell therapies for regeneration or repair of the ischaemic myocardium and their multiple related mechanisms involved in myocardial repair and regeneration.     

Differentiation of embryonic stem cells in adult bone marrow

Embryonic stem cells (ESCs) are a potential source of generating transplantable hematopoietic stem and progenitor cells, which in turn can serve as "seed" cells for hematopoietic regeneration. In this study, we aimed to gauge the ability of mouse ESCs directly differentiating into hematopoietic cells in adult bone marrow (BM). To this end, we first derived a new mouse ESC line that constitutively expressed the green fluorescent protein (GFP) and then injected the ESCs into syngeneic BM via intra-tibia. The progeny of the transplanted ESCs were then analyzed at different time points after transplantation. Notably, however, most injected ESCs differentiated into non-hematopoietic cells in the BM whereas only a minority of the cells acquired hematopoietic cell surface markers. This study provides a strategy for evaluating the differentiation potential of ESCs in the BM micro-environment, thereby having important implications for the physiological maintenance and potential therapeutic applications of ESCs.