Manufacture of a human mesenchymal stem cell population using an automated cell culture platform

Tissue engineering and regenerative medicine are rapidly developing fields that use cells or cell-based constructs as therapeutic products for a wide range of clinical applications. Efforts to commercialise these therapies are driving a need for capable, scaleable, manufacturing technologies to ensure therapies are able to meet regulatory requirements and are economically viable at industrial scale production. We report the first automated expansion of a human bone marrow derived mesenchymal stem cell population (hMSCs) using a fully automated cell culture platform. Differences in cell population growth profile, attributed to key methodological differences, were observed between the automated protocol and a benchmark manual protocol. However, qualitatively similar cell output, assessed by cell morphology and the expression of typical hMSC markers, was obtained from both systems. Furthermore, the critical importance of minor process variation, e.g. the effect of cell seeding density on characteristics such as population growth kinetics and cell phenotype, was observed irrespective of protocol type. This work highlights the importance of careful process design in therapeutic cell manufacture and demonstrates the potential of automated culture for future optimisation and scale up studies required for the translation of regenerative medicine products from the laboratory to the clinic.     

Multilineage potential of stable human mesenchymal stem cell line derived from fetal marrow

Human bone marrow contains two major cell types, hematopoietic stem cells (HSCs) and mesenchymal stem cells (MSCs). MSCs possess self-renewal capacity and pluripotency defined by their ability to differentiate into osteoblasts, chondrocytes, adipocytes and muscle cells. MSCs are also known to differentiate into neurons and glial cells in vitro, and in vivo following transplantation into the brain of animal models of neurological disorders including ischemia and intracerebral hemorrhage (ICH) stroke. In order to obtain sufficient number and homogeneous population of human MSCs, we have clonally isolated permanent and stable human MSC lines by transfecting primary cell cultures of fetal human bone marrow MSCs with a retroviral vector encoding v-myc gene. One of the cell lines, HM3.B10 (B10), was found to differentiate into neural cell types including neural stem cells, neurons, astrocytes and oligodendrocytes in vitro as shown by expression of genetic markers for neural stem cells (nestin and Musashi1), neurons (neurofilament protein, synapsin and MAP2), astrocytes (glial fibrillary acidic protein, GFAP) and oligodendrocytes (myelin basic protein, MBP) as determined by RT-PCR assay. In addition, B10 cells were found to differentiate into neural cell types as shown by immunocytochical demonstration of nestin (for neural stem cells), neurofilament protein and beta-tubulin III (neurons) GFAP (astrocytes), and galactocerebroside (oligodendrocytes). Following brain transplantation in mouse ICH stroke model, B10 human MSCs integrate into host brain, survive, differentiate into neurons and astrocytes and induce behavioral improvement in the ICH animals. B10 human MSC cell line is not only a useful tool for the studies of organogenesis and specifically for the neurogenesis, but also provides a valuable source of cells for cell therapy studies in animal models of stroke and other neurological disorders.     

Proteomic analysis of microvesicles derived from human mesenchymal stem cells

Mesenchymal stem cells (MSCs) have emerged as a promising means for treating degenerative or incurable diseases. Recent studies have shown that microvesicles (MVs) from MSCs (MSC-MVs) contribute to recovery of damaged tissues in animal disease models. Here, we profiled the MSC-MV proteome to investigate their therapeutic effects. LC-MS/MS analysis of MSC-MVs identified 730 MV proteins. The MSC-MV proteome included five positive and two variable known markers of MSCs, but no negative marker, as well as 43 surface receptors and signaling molecules controlling self-renewal and differentiation of MSCs. Functional enrichment analysis showed that cellular processes represented by the MSC-MV proteins include cell proliferation, adhesion, migration, and morphogenesis. Integration of MSC's self-renewal and differentiation-related genes and the proteome of MSC-conditioned media (MSC-CM) with the MSC-MV proteome revealed potential MV protein candidates that can be associated with the therapeutic effects of MSC-MVs: (1) surface receptors (PDGFRB, EGFR, and PLAUR); (2) signaling molecules (RRAS/NRAS, MAPK1, GNA13/GNG12, CDC42, and VAV2); (3) cell adhesion (FN1, EZR, IQGAP1, CD47, integrins, and LGALS1/LGALS3); and (4) MSC-associated antigens (CD9, CD63, CD81, CD109, CD151, CD248, and CD276). Therefore, the MSC-MV proteome provides a comprehensive basis for understanding the potential of MSC-MVs to affect tissue repair and regeneration.     

Karyotypically normal and abnormal human embryonic stem cell lines derived from PGD-analyzed embryos

Although a normal karyotype is generally a requirement for stem cell lines, new applications are likely to emerge for stem cells with defined chromosomal aneuploidies. We therefore investigated the use of embryos found to be aneuploid on biopsy followed by preimplantation genetic diagnosis (PGD) with fluorescent in situ hybridization (FISH), and developmentally arrested embryos for stem cell derivation. Eleven stem cell lines were obtained from 41 embryos in 36 cultures, with higher success rate achieved from PGD-analyzed, developmentally advanced embryos (45%) than from clinically unsuitable non-PGD embryos (13%). The resulting stem cell lines were karyotyped, and surprisingly, six of the nine lines from aneuploid embryos as well as both lines from non-PGD embryos were karyotypically normal. Three lines from PGD embryos were aneuploid exhibiting trisomy 5, trisomy 16, and an isochromosome 13, respectively. None of the aneuploid lines presented the same anomally as the original PGD analysis. Our study has three important implications. First, we confirm the ability to produce stem cell lines from PGD-tested embryos as well as developmentally abnormal embryos, offering specialty stem cell lines for research into the clinically important aneuploidies. Second, we observe that stem cell derivation from apparently aneuploid embryos is often thwarted by underlying mosaicism and emerging dominance of the stem cell line by karyotypically normal cells. The corollary, however, is that regular production of normal stem cell lines from developmentally abnormal embryos ordinarity discarded opens a new source of embryos for stem cells, whether for research or for eventual therapeutic use within the donating families.     

分离与培养人脂肪组织间充质干细胞的研究

目的：探索人脂肪组织源性间充质干细胞（ASCs）的分离、体外培养,为其广泛应用提供实验依据。方法：无菌条件下获取腹部手术病人皮下脂肪组织,酶消化法分离、培养ASCs,观察细胞形态并绘制细胞生长曲线,计算细胞群体倍增时间;对第2代细胞进行免疫组织化学染色,鉴定其表面分子CD44表达;取2—4代细胞用含体积分数为10％胎牛血清、1％青链霉素原液、1μmmol／L地塞米松、10μmmol／L胰岛素、0．5mmmol／LIBMX的高糖DMEM培养基中诱导培养一周,观察细胞形态变化,并用油红“O”染色定性。结果：人脂肪组织中含有大量间充质干细胞,呈成纤维细胞样贴壁生长,细胞群体倍增时间为55h左右;免疫化学染色鉴定CD44阳性;成脂诱导分化一周,可见细胞内有大量脂滴,油红“0”染色可见胞浆内有大量红染颗粒。结论：建立了一种自人体脂肪组织分离,培养ASCs经济简便的方法,为其能够作为组织工程理想的种子细胞及广泛应用于临床提供实验依据。     

间充质细胞外泌体促进小鼠胰岛内皮细胞血管生成的研究

目的探讨间充质细胞（MSC）外泌体对低氧条件下胰岛内皮细胞（MS-1）血管生成的影响。 方法MSC无血清低氧条件培养48?h,超滤离心法富集条件培养基中的外泌体,采用电镜和Western Blot的方法进行鉴定;通过血管形成试验比较分析不同条件下：常氧培养组（NOR组,21﹪O₂、5﹪CO₂）、低浓度氧培养组（HYP组,2﹪O₂、5﹪CO₂）、外泌体+低浓度氧共培养组（HYP+EXO组,2﹪O₂、5﹪CO₂）,MS-1细胞的血管形成能力;image J软件分析血管形成长度;PCR、Q-PCR检测血管内皮生长因子（VEGF） RNA水平的表达,Western Blot检测VEGF、HIF1α蛋白水平表达以及mTOR信号通路激活情况。采用单因素方差分析和SNK-q检验统计学分析。 结果超滤离心法富集的MSC条件培养基中的外泌体,大小为30 ~ 100 nm,表达CD9,CD63,CD81等外泌体表面标志物;血管形成试验结果显示,低氧促进MS-1血管生成,HYP+EXO组形成明显的血管网状结构;HYP+EXO组血管形成相对长度（2386.0±137.7）像素与NOR组（393.3±174.2）像素和HYP组（1467.0±230.0）像素相比增强,差异有统计学意义（t = 12.30,P?= 0.0065;t = 15.74,P = 0.0040）;PCR结果显示,HYP+EXO组VEGF相对表达量（20.26±9.972）较常氧对照组（1.000）和低氧组（6.521±3.501）均增强,差异有统计学意义（t = 5.462,P = 0.0009;t = 4.238,P = 0.0038）;同时,Western Blot结果显示VEGF蛋白水平表达升高,HIF1-α表达上调,mTOR发生磷酸化。 结论MSC外泌体可促进低氧条件下的小鼠胰岛内皮细胞血管生成。MSC外泌体可能通过上调HIF1-α,调节VEGF表达,激活mTOR信号通路,促进胰岛内皮细胞血管生成。     

Optimization of human umbilical cord mesenchymal stem cell isolation and culture methods

Human umbilical cord mesenchymal stem cells (hUCMSCs) are considered to be an ideal replacement for bone marrow MSCs. However, up to date, there is no convenient and efficient method for hUCMSC isolation and culture. The present study was carried out to explore the modified enzyme digestion for hUCMSC in vitro. Conventional enzyme digestion, modified enzyme digestion, and tissue explant were used on hUCMSCs to compare their efficiencies of isolation and culture, to observe primary cell growth and cell subculture. The results show that the cells cultured using the tissue explant method had a longer culture cycle (P < 0.01) and lower yield of primary cells per centimetre of umbilical cord (P < 0.01) compared with the two enzyme digestion methods. Subculture adherence and cell doubling took significantly less time with the tissue explant method (P < 0.05) than with the conventional enzyme digestion method; however, there was no significant difference between the tissue explant method and the modified enzyme digestion method (P > 0.05). Comparing two enzyme digestion methods, the modified method yielded more cells than did the conventional method (P < 0.01), and primary cell adherence took significantly less time with the modified method than with the conventional method (P < 0.05). Cell cycle analysis of the third-generation hUCMSCs cultured by modified enzyme digestion method indicated that most cells were quiescent. Immunofluorescence staining showed that these cells expressed MSC markers CD44 and CD90. And Von Kossa and oil red O staining detection showed that they could be differentiated into osteoblasts and adipocytes with induction medium in vitro. This study suggests that hUCMSC isolation and culture using 0.2 % collagenase II at 37 °C for digestion of 16–20 h is an effective and simple modified enzyme digestion method.     

Comparative characteristics of new mesenchymal stem cell lines derived from human embryonic stem cells, bone marrow and foreskin

New nonimmortalized fibroblast-like cell lines SC5-MSC and SC3a-MSC, FetMSC, FRSN were obtained from human embryonic stem cells (ESC), bone marrow of a 5-6-days embryo and foreskin of a 3-years-old boy, respectively. All the lines are successfully used as the feeder at human ESC cultivation. It is determined that the average cell population doublings time varies from 25.5 h for ISC5-MSC to 38.8 h for SC3a-MSC. Active proliferation of all the lines is also shown by the corresponding growth curves. Numerical and structural karyotypic analysis showed that these lines had normal karyotype: 46,XX (SC5-MSC and SC3a-MSC) and 46,XY (FetMSC and FRSN). To determine the status of the lines, their cell surface markers were analyzed by flow cytometry. This analysis revealed the presence of surface antigens CD44, CD73, CD90, CD105 and HLA-ABC, characteristic of human MSC, and the absence of CD34 and HLA-DR. Different lines were found to express CD117(c-kit) to a different level. Immunofluorescence and flow cytometry analysis did not detect TRA-1-60 and Oct-4, characteristic of human embryonic stem cells, and revealed interlinear variations in the level of SSEA, which did not depend on the cell origin. It is not clear yet whether these interlinear variations affect functional MSC status. In all the lines, immunofluorescence analysis showed the presence of the markers of early differentiation in the derivates of three germ layers which may allow MSC to be useful, in corresponding microenvironments, for reparation of tissue injures. Adipogenic and osteogenic differentiatiation of all cell lines has been shown.     

Application of mesenchymal stem cells derived from human pluripotent stem cells in regenerative medicine

Mesenchymal stem cells (MSCs) represent the most clinically used stem cells in regenerative medicine. However, due to the disadvantages with primary MSCs, such as limited cell proliferative capacity and rarity in the tissues leading to limited MSCs, gradual loss of differentiation during in vitro expansion reducing the efficacy of MSC application, and variation among donors increasing the uncertainty of MSC efficacy, the clinical application of MSCs has been greatly hampered. MSCs derived from human pluripotent stem cells (hPSC-MSCs) can circumvent these problems associated with primary MSCs. Due to the infinite self-renewal of hPSCs and their differentiation potential towards MSCs, hPSC-MSCs are emerging as an attractive alternative for regenerative medicine. This review summarizes the progress on derivation of MSCs from human pluripotent stem cells, disease modelling and drug screening using hPSC-MSCs, and various applications of hPSC-MSCs in regenerative medicine. In the end, the challenges and concerns with hPSC-MSC applications are also discussed.     

Human embryonic stem cell lines derived from the Chinese population

Six human embryonic stem cell lines were established from surplus blastocysts. The cell lines expressed alkaline phosphatase and molecules typical of primate embryonic stem cells, including Oct-4, Nanog, TDGF1, Sox2, EBAF, Thy-1, FGF4, Rex-1, SSEA-3, SSEA-4, TRA-1-60 and TRA-1-81. Five of the six lines formed embryoid bodies that expressed markers of a variety of cell types; four of them formed teratomas with tissue types representative of all three embryonic germ layers. These human embryonic stem cells are capable of producing clones of undifferentiated morphology, and one of them was propagated to become a subline. Human embryonic stem cell lines from the Chinese population should facilitate stem cell research and may be valuable in studies of population genetics and ecology.     

bFGF promotes adipocyte differentiation in human mesenchymal stem cells derived from embryonic stem cells

In this work we describe the establishment of mesenchymal stem cells (MSCs) derived from embryonic stem cells (ESCs) and the role of bFGF in adipocyte differentiation. The totipotency of ESCs and MSCs was assessed by immunofluorescence staining and RT-PCR of totipotency factors. MSCs were successfully used to induce osteoblasts, chondrocytes and adipocytes. MSCs that differentiated into adipocytes were stimulated with and without bFGF. The OD/DNA (optical density/content of total DNA) and expression levels of the specific adipocyte genes PPARγ2 (peroxisome proliferator activated receptor γ2) and C/EBPs were higher in bFGF cells. Embryonic bodies had a higher adipocyte level compared with cells cultured in plates. These findings indicate that bFGF promotes adipocyte differentiation. MSCs may be useful cells for seeding in tissue engineering and have enormous therapeutic potential for adipose tissue engineering.     

Characterization of mesenchymal stem cells from human normal and hyperplastic gingiva

Human gingiva plays an important role in the maintenance of oral health and shows unique fetal‐like scarless healing process after wounding. Here we isolate and characterize mesenchymal stem cells from human normal and hyperplastic gingival tissues (N‐GMSC and H‐GMSC, respectively). Immunocytochemical staining indicated that gingival lamina propria contained Stro‐1 and SSEA‐4 positive cells, implying existence of putative gingival MSC. Under attachment‐based isolating and culturing condition, gingival MSC displayed highly clonogenic and long‐term proliferative capability. By using single colony isolation and expansion approaches, we found both N‐GMSC and H‐GMSC possessed self‐renewal and multipotent differentiation properties. N‐GMSC and H‐GMSC showed distinct immunoregulatory functions in a murine skin allograft setting via up‐regulation of putative systemic regulatory T cells (Tregs). N‐GMSC and H‐GMSC were capable of regenerating collagenous tissue following in vivo transplantation, in which H‐GMSC exhibited more robust regenerative capability. These findings suggest that gingival tissue contains tissue‐specific mesenchymal stem cell population and is an ideal resource for immunoregulatory therapy due to its substantial availability and accessibility. In addition, gingival MSC over‐activation may contribute to gingival hyperplastic phenotype. J. Cell. Physiol. 226: 832–842, 2011. © 2010 Wiley‐Liss, Inc.     

Functional studies of mesenchymal stem cells derived from adult human adipose tissue

Recent evidence suggests that cells with the properties of human mesenchymal stem cells (hMSCs) can be derived from adult peripheral tissues, including adipose tissue, muscle and dermis. We isolated hMSCs from the stromal-vascular portion of subcutaneous adipose tissue from seven adult subjects. These cells could be readily differentiated into cells of the chondrocyte, osteocyte and adipocyte lineage demonstrating their multipotency. We studied the functional properties of hMSCs-derived adipocytes and compared them with adipocytes differentiated from hMSCs obtained from bone marrow (BM-hMSC). The two cell types displayed similar lipolytic capacity upon stimulation with catecholamines, including a pronounced antilipolytic effect mediated through alpha2A-adrenoceptors, a typical trait in human but not rodent fat cells. Furthermore, both cell types secreted the fat cell-specific factors leptin and adiponectin in comparable amounts per time unit. The fat tissue-derived hMSCs retained their differentiation capacity up to at least fifteen passages. We conclude that hMSCs derived from adult human adipose tissue can be differentiated into fully functional adipocytes with a similar, if not identical, phenotype as that observed in cells derived from BM-hMSCs. Human adipose-tissue-derived MSCs could therefore constitute an efficient and easily obtainable renewable cellular source for studies of adipocyte biology.     

Animal serum-free culture conditions for isolation and expansion of multipotent mesenchymal stromal cells from human BM

BACKGROUND: Multipotent mesenchymal stromal cells (MSC) have become important tools in regenerative and transplantation medicine. Rapidly increasing numbers of patients are receiving in vitro-expanded MSC. Culture conditions typically include FSC because human serum does not fully support growth of human MSC in vitro (MSC(FCS)). Concerns regarding BSE, other infectious complications and host immune reactions have fueled investigation of alternative culture supplements. METHODS: As PDGF has long been identified as a growth factor for MSC, we tested media supplementation with platelet lysate for support of MSC proliferation. RESULTS: We found that primary cultures of BM-derived MSC can be established with animal serum-free media containing fresh frozen plasma and platelets (MSC(FFPP)). Moreover, MSC(FFPP) showed vigorous proliferation that was superior to classical culture conditions containing FCS. MSC(FFPP) morphology was equivalent to MSC(FCS), and MSC(FFPP) expressed CD73, CD90, CD105, CD106, CD146 and HLA-ABC while being negative for CD34, CD45 and surface HLA-DR, as expected. In addition to being phenotypically identical, MSC(FFPP) could efficiently differentiate into adipocytes and osteoblasts. In terms of immune regulatory properties, MSC(FFPP) were indistinguishable from MSC(FCS). Proliferation of PBMC induced by IL-2 in combination with OKT-3 or by PHA was inhibited in the presence of MSC(FFPP). DISCUSSION: Taken together, FCS can be replaced safely by FFPP in cultures of MSC for clinical purposes.     

Autoreactive T cells induce in vitro BM mesenchymal stem cell transdifferentiation to neural stem cells

BACKGROUND: The degree of post-injury inflammation of the damaged area of a spinal cord is the main difference between the natural successful repair in inferior vertebrates and failure in superior vertebrates. The treatment of rats with anti-myelin lymphocytes after experimental spinal cord injury induces their functional recovery. On the other hand, mesenchymal stem cells (MSC) from adult BM implanted in injured areas recover the morphology and function of spinal cord in mammals. The purpose of this study was to determine whether there is a direct relationship between anti-nervous tissue T cells and MSC reparatory properties. METHODS: Circulating autoreactive lymphocytes of patients with spinal cord injuries and amyotrophic lateral sclerosis were isolated and activated in vitro. These cells were cocultured with autologous MSC for 2-15 days. Cocultures of non-selected lymphocytes were used as controls. RESULTS: After 48 h of coculture, MSC adopted a spindle shape with polarization of the cytoplasm that resembled bipolar neurons. Their nuclei diminished the nucleolus number and the chromatin lost its granular appearance. After 15 days of culture the cells developed the typical structure of a neural network. No morphologic changes were observed in control cultures. The differentiated cells reacted positively to tubuline III, GFAP and nestin. No differences were observed between the different patient cell sources. DISCUSSION: We observed that autoreactive cells may induce the transdifferentiation of MSC to neural stem cells. This T-cell-MSC interaction may be a common phenomenon during physiologic nerve tissue repair.