Analysis of neuron-like differentiation of human bone marrow mesenchymal stem cells

The objective of the study was to evaluate differentiation of human bone marrow mesenchymal stem cells into true or pseudo neurons after treating with chemical induction medium in vitro. The morphological changes were assessed using interference contrast microscopy. Immunocytochemistry and Western blotting were performed using neuronal markers. Further evaluation was conducted with proteomic profiling, DNA microarray analysis and the whole-cell patch clamp test. After three hours of treatment with chemical induction medium, nearly three-fourths of the hMSCs changed to cells with a neuronal phenotype. The results of immunocytochemistry and Western blotting showed a high expression of neuronal markers in these cells at 3 h which decreased at 24 h. The proteomics analysis showed no change of proteins related to neuronal differentiation. DNA microarray showed downregulation of neuron related genes. The patch clamp test was unable to demonstrate any similarity to true neurons. Our findings suggest that neuron-like cells derived from chemical induction of hMSCs are not the genuine neurons as they resemble true neurons phenotypically but are different in genotypic and electrophysiological characteristics.     

体外化学诱导人骨髓间充质干细胞分化为心肌样细胞

To investigate the potential of adult mesenchymal stem cells (hMSCs) derived from human bone marrow to undergo cardiomyogenic differentiation after exposure of 5-azacytidine in vitro. A small bone marrow aspirate was taken from the iliac crest of human volunteers, and hMSCs were isolated by 1.073 g/mL Percoll and cultured in the right cell culturing medium as previously described. The phonotypes of hMSCs were identified by flow cytometry. The stem cells were cultured in cell culture medium (as control) and medium mixed with 5-azacytidine (5-aza, 3, 5, 10 micromol/L) (n=5, respectively) for cellular differentiation. We examined respectively with immunohischemistry at 21 days of inducement on desmin, cardiac-specific cardiac troponin I (cTnI), GATA4 & connexin43. The ultrastructures of induced cells were examined by transmission electron microscope. The results indicated that the hMSCs showed a fibroblast-like morphology with vortex distribution in their peak propagation, and express high level of CD44 but negative for CD34 and CD45. 20%-30% cells grown after 5, 10 microl/L 5-aza treatment connected with adjoining cells and coalesced into myotube structures after 14 days. After 21 days of culturing, immunohistochemistry revealed expression of desmin, GATA4, cTnI and connexin43 in 5, 10 micromol/L showed positive, but no cardiac specific protein were found in neither 3 micromol/L nor in control group. The ratio of cTnI positive stained cells in 10 micromol/L group were higher than that in 5 micromol/L group (65.3+/-4.7% vs 48.2+/-5.4%, p<0.05). Electron microscopy revealed myofilaments were formed. The results indicated that purified hMSCs from adult bone marrow can be differentiated into cardiac-like muscle cells with 5-aza inducement in vitro and the differentiation is in line with the 5-aza concentration.     

人骨髓间充质干细胞向血管内皮细胞诱导分化的研究

目的:分析人骨髓间充质干细胞(hMSCs)和脐静脉内皮细胞(hUVECs)的基因表达差异,探讨体外基因转染诱导内皮分化的可行性以及作为血管组织工程种子细胞来源的应用前景。方法:分别从人骨髓和脐静脉分离间充质干细胞(hMSCs)和内皮细胞(hUVECs),扩增培养后进行流式细胞仪、免疫细胞化学,免疫荧光鉴定和超微结构观察。通过BiostarH-40S表达谱芯片分析,选择两者的差异表达基因,导入hMSCs,经RT-PCR、ELISA鉴定该基因的转染和表达,并分析hMSCs的内皮分化程度。结果:hMSCs表达内皮细胞的多种特异性mRNA,经VEGFl65基因瞬时转染后RT-PCR有明显条带,ELISA定量检测VEGF165蛋白表达为(707.9±11.3)ng/L,同时CD44表达明显下调38.80%,CD31则明显上调达56.82%,FI-1,FVⅢAg和CD34的表达也有不同程度升高。结论:hMSCs具有内皮分化潜能,体外基因转染诱导hMSCs产生功能性内皮细胞和组织工程化血管具有广阔前景。     

Leukemia inhibitory factor contributes to hepatocyte-like differentiation of human bone marrow mesenchymal stem cells

The current majority of protocols for hepatocyte differentiation of mesenchymal stem cells (MSCs) are conducted using oncostatin M (OSM) as an inducer of hepatocyte-like maturation. As leukemia inhibitory factor (LIF) and OSM share similar signaling pathways, we examined whether LIF could play a role in the hepatocyte differentiation process. A differentiation protocol was designed using LIF as a maturation cytokine and this was compared with standard and control protocols applied to human MSCs of bone marrow origin. We observed that mesenchymal-derived hepatocyte-like cells (MDHLCs) acquired similar morphological changes when exposed to LIF or to OSM. Using protein and gene expression assays, we noticed a comparable hepatic marker expression in both differentiation conditions. Furthermore, LIF and OSM allowed the acquisition of equivalent levels of hepatocyte-like functionality as attested by evaluation of urea secretion and glycogen deposition. However, no increase in the expression of hepatocyte-like features could be observed in MDHLCs after a combined exposition to LIF and OSM. In conclusion, we demonstrated that LIF can play a similar role as OSM in the hepatocyte differentiation process of human MSCs.     

人骨髓间充质干细胞在成年大鼠脑内的迁移及分化

骨髓间充质干细胞 (mesenchymalstemcells,MSCs)是目前备受关注的一类具有多向分化潜能的组织干细胞 ,体外可以分化为骨、软骨、脂肪等多种细胞。因此 ,MSCs是细胞治疗和基因治疗的种子细胞之一。为了探索MSCs的迁移和分化趋势 ,为帕金森病 (Parkinsondisease,PD)的干细胞治疗提供理论和实验依据 ,本实验将体外扩增并转染增强型绿色荧光蛋白 (enhancedgreenfluorescentprotein ,EGFP)的人骨髓MSCs注入PD大鼠脑内纹状体 ,观察了人骨髓MSCs在大鼠脑内的存活、迁移、分化以及注射MSCs前后大鼠的行为变化。结果表明 ,人骨髓MSCs在大鼠脑内可存活较长时间 ( 10周以上 ) ;随着时间的延长 ,MSCs迁移范围扩大 ,分布于纹状体、胼胝体、皮质以及脑内血管壁 ;免疫组化法检测证实MSCs在大鼠脑内表达人神经丝蛋白 (neurofilament,NF)、神经元特异性烯醇化酶 (neuron specificeno lase,NSE)以及胶质原纤维酸性蛋白 ( glialfibrillaryacidprotein ,GFAP) ;PD大鼠的异常行为有所缓解 ,转圈数由 8 86±2 0 9r/min下降到 4 87± 2 0 6r/min ,统计学分析P <0 0 5为差异显著。以上观察结果表明 ,骨髓MSCs有望成为治疗PD的种子细胞     

Xeno-free proliferation of human bone marrow mesenchymal stem cells

The proliferation of human bone marrow mesenchymal stem cells (MSCs) employing xeno-free materials not containing fetal calf serum (FCS) and porcine trypsin was investigated for the regenerative medicine of cartilage using MSCs. Four sequential subcultivations of MSCs using a medium containing 10% FCS and recombinant trypsin (TrypLESelect™) resulted in cell growth comparable to that with porcine trypsin. There was no apparent difference in the cell growth and morphology between two kinds of MSC stored in liquid nitrogen using 10% FCS plus DMSO or serum-free TC protector™. MSCs were isolated from human bone marrow cells, stored in liquid nitrogen, and sequentially subcultivated four times employing conventional materials that included FCS, porcine trypsin, and DMSO, or xeno-free materials that included serum-free medium (MesenCult-XF™), TC protector™ and TrypLESelect™. Cells in the culture using the xeno-free materials maintained typical fibroblast-like morphology and grew more rapidly than the cells in the culture using the conventional materials, while the cell surface markers of MSCs (CD90 and CD166) were well maintained in both cultures. Chondrogenic pellet cultures were carried out using these subcultivated cells and a medium containing TGFβ3 and IGF1. The pellet culture using cells grown with the xeno-free materials showed an apparently higher gene expression of aggrecan, a chondrocyte marker, than the pellet culture using cells grown with the conventional materials. Consequently, MSCs that are isolated, stored, and grown using the xeno-free materials including the serum-free medium (MesenCult-XF™), TC protector™, and recombinant trypsin (TrypLESelect™) might be applicable for regenerative medicine of cartilage.     

Isolation of mesenchymal stem cells from human placenta: comparison with human bone marrow mesenchymal stem cells

The presence within bone marrow of a population of mesenchymal stem cells (MSCs) able to differentiate into a number of different mesenchymal tissues, including bone and cartilage, was first suggested by Friedenstein nearly 40 years ago. Since then MSCs have been demonstrated in a variety of fetal and adult tissues, including bone marrow, fetal blood and liver, cord blood, amniotic fluid and, in some circumstances, in adult peripheral blood. MSCs from all of these sources can be extensively expanded in vitro and when cultured under specific permissive conditions retain their ability to differentiate into multiple lineages including bone, cartilage, fat, muscle, nerve, glial and stromal cells. There has been great interest in these cells both because of their value as a model for studying the molecular basis of differentiation and because of their therapeutic potential for tissue repair and immune modulation. However, MSCs are a rare population in these tissues. Here we tried to identify cells with MSC-like potency in human placenta. We isolated adherent cells from trypsin-digested term placentas and examined these cells for morphology, surface markers, and differentiation potential and found that they expressed several stem cell markers. They also showed endothelial and neurogenic differentiation potentials under appropriate conditions. We suggest that placenta-derived cells have multilineage differentiation potential similar to MSCs in terms of morphology and cell-surface antigen expression. The placenta may prove to be a useful source of MSCs.     

Tissue-engineered bone formation with cryopreserved human bone marrow mesenchymal stem cells

Bone marrow mesenchymal stem cells (MSCs) have become the main cell source for bone tissue engineering. It has been reported that cryopreserved human MSCs can maintain their potential for proliferation and osteogenic differentiation in vitro. There are, however, no reports on osteogenesis with cryopreserved human MSCs in vivo. The aim of this study was to determine whether cryopreservation had an effect on the proliferation capability and osteogenic differentiation of human MSCs on scaffolds in vitro and in vivo. MSCs were isolated from human bone marrow, cultured in vitro until passage 2, and then frozen and stored at −196 °C in liquid nitrogen with 10% Me₂SO as cryoprotectant for 24 h. The cryopreserved MSCs were then thawed rapidly, seeded onto partially demineralized bone matrix (pDBM) scaffolds and cultured in osteogenic media containing 10 mM sodium β-glycerophosphate, 50 μM l-ascorbic acid, and 10 nM dexamethasone. Non-cryopreserved MSCs seeded onto the pDBM scaffolds were used as control groups. Scanning electronic microscopy (SEM) observation, DNA content assays, and measurements of alkaline phosphatase (ALP) activity and osteocalcin (OCN) content were applied, and the results showed that the proliferation potential and osteogenic differentiation of MSCs on pDBM in vitro were not affected by cryopreservation. After 2 weeks of subculture, the MSCs/pDBM composites were subcutaneously implanted into the athymic mice. The constructs were harvested at 4 and 8 weeks postimplantation, and histological examination showed tissue-engineered bone formation in the pDBM pores in both groups. Based on these results, it can be concluded that cryopreservation allows human MSCs to be available for potential therapeutic use to tissue-engineer bone.     

Culture and differentiation of osteoblasts on coral scaffold from human bone marrow mesenchymal stem cells

In this paper we describe an approach that aims to provide fundamental information towards a scientific, biomechanical basis for the use of natural coral scaffolds to initiate mesenchymal stem cells into osteogenic differentiation for transplant purposes. Biomaterial, such as corals, is an osteoconductive material that can be used to home human derived stem cells for clinical regenerative purposes. In bone transplantation, the use of biomaterials may be a solution to bypass two main critical obstacles, the shortage of donor sites for autografts and the risk of rejection with allograft procedures. Bone regeneration is often needed for multiple clinical purposes for instance, in aesthetic reconstruction and regenerative procedures. Coral graft Porites lutea has been used by our team for a decade in clinical applications on over a thousand patients with different bone pathologies including spinal stenosis and mandibular reconstruction. It is well accepted that human bone marrow (hBM) is an exceptional source of mesenchymal stem cells (MSCs), which may differentiate into different cell phenotypes such as osteoblasts, chondrocytes, adipocytes, myocytes, cardiomyocytes and neurons. Isolated MSCs from human bone marrow were induced into osteoblasts using an osteogenic medium enriched with two specific growth factors, FGF9 and vitamin D2. Part of the cultured MSCs were directly transferred and seeded onto coral scaffolds (Porites Lutea) and induced to differentiate into osteoblasts and part were cultured in flasks for osteocell culture. The data support the concept that hBM is a reliable source of MSCs which may be easily differentiated into osteoblasts and seeded into coral as an optimal device for clinical application. Within this project we have also discussed the biological nature of MSCs, their potential application for clinical transplantation and the prospect of their use in gene therapy.     

Cholinergic neuronal differentiation of bone marrow mesenchymal stem cells in rhesus monkeys

The purpose of the present study was to determine the best cholinergic neuronal differentiation method of rhesus monkey bone marrow mesenchymal stem cells(BMSCs).Four methods were used to induce differentiation,and the groups were assigned accordingly:basal inducing group(culture media,bFGF,and forskolin);SHH inducing group(SHH,inducing group);RA inducing group(RA,basal inducing group);and SHH+RA inducing group(SHH,RA,and basal inducing group).All groups displayed neuronal morphology and increased expressio...     

The immunobiological development of human bone marrow mesenchymal stem cells in the course of neuronal differentiation

The central nervous system (CNS) has been referred to as the "immunological privileged site". However, it is now clear that the privileged status of the CNS is a result of a balance between immune privilege and effective response. In vitro, human bone marrow mesenchymal stem cells (MSCs) have the ability to differentiate into neurons. Based on this biological attribute we gain the possibility by means of using MSCs as the donors to develop a future cell therapy in clinical application. But using MSCs as donor cells inevitably raises the question as to whether these donor cells would be immunogenic, and if so, would they be rejected after transplantation. To investigate this, human MSCs were cultured in vitro and induced to differentiate along neuronal lineage. The expression of human leukocyte antigen (HLA) class I and class II molecules and the co-stimulatory protein CD80 were increased on the surface of MSCs in the course of neuronal differentiation. But neither of the co-stimulatory proteins, CD40 or CD86, was expressed. After IFN-gamma exposure, the expression of the HLA molecules was further enhanced, but the co-stimulatory proteins were unaffected. MSCs that had been differentiated along neuronal lineage were not capable of inducing the proliferation of peripheral blood lymphocytes (PBLs). Even after IFN-gamma exposure, PBLs remained unresponsive. Furthermore, MSCs differentiated along neuronal lineage suppressed the proliferation of PBLs induced by allogeneic PBLs and mitogens. The mechanisms involved in the immunosuppression may be related to the effect of soluble factors and cell-cell interactions of neuronal differentiated MSCs and PBLs. From the above data we suggested that the low immunogenicity and immunomodulatory function of MSCs in the course of neuronal differentiation in vitro, which will be helpful to further investigation in order to establish the new way for future medical application.     

Cytokine-induced stable neuronal differentiation of human bone marrow mesenchymal stem cells in a serum/feeder cell-free condition

The characteristics and multilineage differentiation potential of bone marrow mesenchymal stem cells (BM MSC) remain controversial. This study aimed to characterize human BM MSC isolated by plastic adherent or antibody selection and their neuronal differentiation potential using growth factors or chemical inducing agents. MSC were found to express low levels of neuronal markers: neurofilament-M, beta tubulin III, and neuron specific enolase. Under a serum- and feeder cell-free condition, basic fibroblast growth factor, epidermal growth factor, and platelet-derived growth factor induced neuronal morphology in MSC. In addition to the above markers, these cells expressed neurotransmitters or associated proteins: gamma-aminobutyric acid, tyrosine hydroxylase and serotonin. These changes were maintained for up to 3 months in all bone marrow specimens (N = 6). In contrast, butylated hydroxyanisole and dimethylsulfoxide were unable to induce sustained neuronal differentiation. Our results show that MSC isolated by two different procedures produced identical lineage differentiation with defined growth factors in a serum- and feeder cell-free condition.     

A number of bone marrow mesenchymal stem cells but neither phenotype nor differentiation capacities changes with age of rats

Bone marrow (BM) derived mesenchymal stem cells (MSC) are pluripotent cells which can differentiate into osteogenic, adipogenic and other lineages. In spite of the broad interest, the information about the changes in BM cell composition, in particularly about the variation of MSC number and their properties in relation to the age of the donor is still controversial. The aim of this study was to investigate the age associated changes in variations of BM cell composition, phenotype and differentiation capacities of MSC using a rat model. Cell populations were characterized by flow cytometry using light scattering parameters, DNA content and a set of monoclonal antibodies. Single cell analysis was performed by conventional fluorescent microscopy. In vitro culture of MSC was established and their phenotype and capability for in vitro differentiation into osteogenic and adipogenic cells was shown. Age related changes in tibiae and femurs, amount of BM tissue, BM cell composition, proportions of separated MSC and yield of MSC in 2 weeks of in vitro culture were found. At the same time, neither change in phenotype no in differentiation capacities of MSC was registered. Age-related changes of the number of MSC should be taken into account whenever MSC are intended to be used for investigations.     

Hepatic stellate cells modulate the differentiation of bone marrow mesenchymal stem cells into hepatocyte-like cells

Differentiation of stem cells is tightly regulated by the microenvironment which is mainly composed of nonparenchymal cells. Herein, we investigated effect of hepatic stellate cells (HSCs) in different states on mesenchymal stem cells (MSCs) differentiation. Rat HSCs were isolated and stayed quiescent within 5 days. Primary HSCs were activated by being in vitro cultured for 7 days or cocultured with Kupffer cells for 5 days. MSCs were cocultured with HSCs of different states. Expression of hepatic lineage markers was analyzed by RT-PCR and immunofluorescence. Glycogen deposition was detected by periodic acid-schiff staining. MSCs cocultured with HSC-T6 or Kupffer cell activated HSCs were morphologically transformed into hepatocyte-like cells. Hepatic-specific marker albumin was expressed in 78.3% of the differentiated MSCs 2 weeks after initiation of coculture. In addition, the differentiated MSCs also expressed alpha-fetoprotein, cytokeratin-18, glutamine synthetase and phosphoenolpyruvate carboxykinase. Glycogen deposition was detectable in 55.4% of the differentiated MSCs 6 weeks after initiation of coculture. However, the quiescent HSCs or culture activated HSCs did not exert the ability to modulate the differentiation of MSCs. Moreover, Kupffer cell activated HSCs rather than culture activated HSCs expressed hepatocyte growth factor mRNA. We draw the conclusion that fully activated HSCs could modulate MSCs differentiation into hepatocyte-like cells.     

Characterization and hepatogenic differentiation of mesenchymal stem cells from human amniotic fluid and human bone marrow: a comparative study

Since stem cells can differentiate into hepatocyte, stem cell-based therapy becomes a potential alternative treatment for terminal liver diseases. However, an appropriate source of human mesenchymal stem cells (hMSCs) for hepatocytes has not yet been clearly elucidated. The aim of the present study was to investigate the in vitro biological characterization and hepatic differentiation potential of human amniotic fluid-derived mesenchymal stem cells (AF-hMSCs) and human bone marrow-derived mesenchymal stem cells (BM-hMSCs). Our results show that AF-hMSCs possess higher proliferation and self-renewal capacity than BM-hMSCs. Cytogenetic studies indicate that AF-hMSCs are as genetically stabile as BM-hMSCs. Following incubation with specific hepatogenic agents, AF-hMSCs showed a higher hepatic differentiation potential than BM-hMSCs. Expression of several liver-specific markers was significantly greater in AF-hMSCs than in BM-hMSCs, as shown by real time RT-PCR and immunofluorescence (IF). In conclusion, AF-hMSCs possess superior potential for hepatic differentiation, making them more suitable for diverse terminal liver diseases.