Clonal Mesenchymal Stem Cells Research Articles

Mesenchymal stromal cells for steroid-refractory acute graft-versus-host disease: a report of two cases

Severe graft-versus-host disease (GVHD) is a lethal complication of allogeneic hematopoietic stem cell transplantation (HSCT). However, there have been only a few limited therapeutic options for the treatment of GVHD. Here we have reported two cases of the patients with acute steroid-refractory GVHD who underwent allogeneic HSCT. These patients received infusions of third-party clonal mesenchymal stem cells (cMSCs), which were isolated by a subfractionation culturing method (SCM) developed recently by our group, and showed marked improvement of the disease. MSCs represent a new potential therapeutic option in the treatment of steroid-refractory acute GVHD. They showed safety and improved clinical findings of the acute GVHD patients. However, further investigations are needed to understand the accurate mechanisms of MSCs and larger well-designed human clinical trials are necessary to prove further the safety and efficacy of the cMSCs for the treatment of acute GVHD patients.

Xenoreactivity of human clonal mesenchymal stem cells in a major histocompatibility complex-matched allogeneic graft-versus-host disease mouse model

Effects of mesenchymal stem cells (MSCs) on graft-versus-host disease (GVHD) have been actively investigated since the discovery of the immunomodulation property of MSCs about a decade ago. Human clonal MSCs (hcMSCs) were isolated from human bone marrow aspirate according to our newly established isolation protocol called subfractionation culturing method, and were evaluated for their efficacy on GVHD treatment, using a mouse MHC-matched B6 → BALB.B GVHD model system. Although the hcMSCs can suppress the allogeneic proliferation of human peripheral blood mononuclear cells in in vitro, the administration of the hcMSCs failed to reduce the GVHD-related mortality of the murine recipients. One of the reasons might be that murine cytokines such as IFN-γ and TNF-α cannot activate the hcMSCs. Based on these results, we suggest that xenogeneic MSCs may not be used for the treatment of GVHD.

Clonal mesenchymal stem cells derived from human bone marrow can differentiate into hepatocyte‐like cells in injured livers of SCID mice

There is increasing evidence that human mesenchymal stem cells (hMSCs) can be a valuable, transplantable source of hepatocytes. Most of the hMSCs preparations used in these studies were likely heterogeneous cell populations, isolated by adherence to plastic surfaces or by density gradient centrifugation. Therefore, the participation of other unknown trace cell populations cannot be rigorously discounted. Here we report the isolation and establishment of a cloned human MSC line (chMSC) from human bone marrow primary culture, through which we confirmed the hepatic differentiation capability of authentic hMSCs. chMSCs expressed markers of mesenchymal cells, but not markers of hematopoietic stem cells. In vitro, chMSCs can differentiate into either mesenchymal cells or cells exhibiting hepatocyte-like phenotypes. When transplanted intrasplentically into carbon tetrachloride-injured livers of SCID mice, EGFP-tagged chMSCs engrafted into the host liver parenchyma, exhibited typical hepatocyte morphology, form a three-dimensional architecture, and differentiate into hepatocyte-like cells expressing human albumin and alpha-1-anti-trypsin. By confocal microscopy, ultrafine intercellular nanotubular structures were visible between adjacent transplanted and host hepatocytes. We postulate that these structures may assist in the phenotype conversion of chMSCs, possibly by exchange of cytoplasmic components between native hepatocytes and transplanted cells. Thus, a clonal pure population of hMSCs, which can be expanded in culture, may have potential as a cellular source for substitution damaged cells in hepatic injury.

Suppression of Carbon Tetrachloride-Induced Liver Fibrosis by Transplantation of a Clonal Mesenchymal Stem Cell Line Derived from Rat Bone Marrow

Transplantation of hepatocytes or bone marrow-derived cells has been shown to ameliorate liver fibrosis in animal models, but no direct comparison of relative efficiency has been made. The aim of this study was to compare the efficiency of a bone marrow-derived clonal mesenchymal stem cell line established by us (rBM25/S3) with that of its adipogenic or hepatogenic differentiation derivative for suppression of rat liver fibrosis. After induction of differentiation of rBM25/S3 cells into adipogenic or hepatogenic cells in culture, we intrasplenically transplanted the three types of cells into rats (3 x 10(7) cells/rat) before and 4 weeks after initiation of carbon tetrachloride treatment (1 ml/kg body weight twice a week for 8 weeks) to induce liver fibrosis. Undifferentiated rBM25/S3 cells were the most effective for suppression of liver fibrosis, followed by the adipogenic cells and hepatogenic cells. Expression levels of MMP-2 and MMP-9 were also highest in undifferentiated rBM25/S3 cells. These results indicate that bone marrow-derived clonal mesenchymal stem cell lines are useful for further mechanistic studies on cell-mediated suppression of liver fibrosis and that such cell lines will provide information on an appropriate cell source for transplantation therapy for cirrhosis.

Demonstration of the presence of independent pre-osteoblastic and pre-adipocytic cell populations in bone marrow-derived mesenchymal stem cells

Mesenchymal stem cells (MSC) are defined as plastic-adherent, clonal cells that are common progenitors for osteoblasts and adipocytes. An inverse relationship between bone and fat has been observed in several clinical conditions and has been suggested to be caused by re-directing MSC differentiation into one particular lineage. However, this inverse relationship between bone and fat is not consistent and under certain in vivo conditions, bone and fat can change independently suggesting separate precursor cell populations. In order to test for this hypothesis, we extensively characterized two plastic-adherent clonal MSC lines (mMSC1 and mMSC2) derived from murine bone marrow. The two cell lines grew readily in culture and have undergone more than 100 population doublings with no apparent differences in their growth rates. Both cell lines were positive for the murine MSC marker Sca-1 and mMSC1 was also positive for CD13. Both cell lines were exposed to in vitro culture induction of osteogenesis and adipogenesis. mMSC1 and not mMSC2 were only able to differentiate to adipocytes evidenced by the expression of adipocyte markers (aP2, adiponectin, adipsin, PPARγ2 and C/EBPa) and the presence of mature adipocytes visualized by Oil Red O staining. On the other hand, mMSC2 and not mMSC1 differentiated to osteoblast lineage as demonstrated by up-regulation of osteoblastic makers (CBFA1/RUNX2, Osterix, alkaline phosphatase, bone sialoprotein and osteopontin) and formation of alizarin red stained mineralized matrix in vitro. Consistent with the in vitro results, mMSC2 and not mMSC1, were able to form bone in vivo after subcutaneous implantation in immune-deficient (NOD/SCID) mice. Our data suggest that contrary to the current belief, bone marrow contains clonal subpopulations of cells that are committed to either osteoblast or adipocyte lineage. These cell populations may undergo independent changes during aging and in bone diseases and thus represent important targets for therapy.

A biomarker‐based mathematical model to predict bone‐forming potency of human synovial and periosteal mesenchymal stem cells

To develop a biomarker-based model to predict osteogenic potency of human mesenchymal stem cells (MSCs) from synovial membrane and periosteum. MSC populations were derived from adult synovium and periosteum. Phenotype analysis was performed by fluorescence-activated cell sorting and real-time reverse transcriptase-polymerase chain reaction (RT-PCR). Telomere lengths were determined by Southern blot analysis. In vitro osteogenesis was assessed quantitatively by measurements of alkaline phosphatase activity and calcium deposits. To investigate bone formation in vivo, MSCs were seeded onto osteoinductive scaffolds and implanted subcutaneously in nude mice. Bone was assessed by histology, and the human origin investigated by in situ hybridization for human Alu genomic repeats. Quantitation was achieved by histomorphometry and real-time RT-PCR for human osteocalcin. Analysis at the single-cell level was performed with clonal populations obtained by limiting dilution. Multiple regressions were used to explore the incremental predictive value of the markers. Periosteal MSCs had significantly greater osteogenic potency than did synovial MSCs inherent to the single cell. Bone was largely of human origin in vivo. Within the same tissue type, there was variability between different donors. To identify predictors of osteogenic potency, we measured the expression levels of osteoblast lineage genes in synovial and periosteal clonal MSCs prior to osteogenic treatment. We identified biomarkers that correlated with osteogenic outcome and developed a mathematical model based on type I collagen and osteoprotegerin expression that predicts the bone-forming potency of MSC preparations, independent of donor-related variables and tissue source. Our findings indicate that our quality-control mathematical model estimates the bone-forming potency of MSC preparations for bone repair.

Differentiation of Mesenchymal Stem Cells from Rat Bone Marrow into Dopaminergic Neuron-Like Cells In Vitro.

Mesenchymal stem cells (MSC) from bone marrow cavity are multipotent cells. Their primary function is to support the growth and differentiation of hematologic progenitors. MSCs have been shown to differentiate into a variety of cell types including: bone, adipocytes, cartilage, neuron-like, and muscle-like cells. This project aimed to induce MSCs from rat bone marrow into mature dopamine secreting cells. MSCs were isolated from rat bone marrow, cultured and passaged. After propagating for three generations in vitro culture, MSCs were induced by epidermal growth factor, basic fibroblast growth factor and retinoic acid. After induction, morphologic change was examined by light microscope. NSE,MAP-2a, b and tyrosine hydroxylase (TH) was examined by immunocytochemistry. The related genes of the differentiated neurons, such as Nurr-1, nestin, mash-1,DR2-L,AADC and TH were detected by RT-PCR. After MSCs were inducted for 7 days,14 days and 21 days, dopamine production and release in the extract and medium of dopaminergic-induced cultured cells was assayed by dopamine ELISA. After 14 days of induction, MSC showed neuron-like morphologic changes and expressed NSE, MAP-2a, b and TH. RT-PCR. showed that these induced cells expressed nerves stem cells gene Nestin,Nurr-1 and dopamine nerves gene mash-1,DR2-L,AADC,TH. Most importantly, dopamine ELISA analysis showed the evidence of dopamine release in the extract and medium of dopaminergic-induced clonal MSCs. The results suggest that bone marrow MSCs from rat can be induced to differentiate into dopaminergic neuron-like cells in vitro. Bone marrow MSCs will provide a promising source of neural progenitor cells and may be a favorable candidate for cellular therapy of Parkinson's disease.

Absence of the p53 tumor suppressor gene promotes osteogenesis in mesenchymal stem cells

Objective Osteosarcoma arises predominantly in the metaphyseal growth plate of children during the growth spurt years. These tumors develop during physiological growth from an expanding cell population, suggesting that the transformed cell is a bone-forming progenitor. An absence of the p53 oncogene has been implicated in the origin and progression of osteosarcoma, and because mesenchymal stem cells (MSCs) are the physiological osteogenic progenitor cell population, we hypothesized that a p53 −/− mutation would enhance bone differentiation of MSC in a mouse model of in vitro osteogenesis. Methods Clonal MSC populations were derived from p53 −/− mice. P53 −/− and wild-type cells were placed in osteogenic culture and assessed via Alizarin Red quantification and alkaline phosphatase staining. The osteogenic marker genes Cbfa1, osteopontin, and osteocalcin were assessed by quantitative real time polymerase chain reaction during differentiation. Results Bone nodule formation and alkaline phosphatase staining was accelerated and enhanced in the p53 −/− cells. The early and intermediate osteogenic markers, Cbfa1 and osteopontin, were upregulated in p53 −/− MSCs compared with wild-type cells during osteogenesis. The terminal osteogenic marker gene osteocalcin was paradoxically lower in p53 −/− MSCs indicating impaired terminal differentiation. Conclusion The p53 −/− mutation enhances and accelerates early osteogenesis in MSCs, but prevents terminal differentiation toward a mature osteocyte phenotype. These findings may have important implications for the regulation of the MSC compartment during the derivation of osteosarcoma in children.

Non-Hematopoietic Bone Marrow Cells Can Be Mobilized and Differentiate into Cardiomyocytes after Myocardial Infarction: Possible Contribution of Mesenchymal Stem Cells.

Recent studies have suggested that bone marrow (BM) cells can contribute to regeneration processes in various tissues. Cardiomyocytes derived from BM cells have been observed after myocardial infarction (MI), and BM-derived cells mobilized by cytokines were capable of regenerating the myocardial tissue, leading to an improvement in survival or cardiac function after MI. However, the responsible BM cells have not been fully identified. The most likely candidates for the BM-derived stem cells with the ability to regenerate myocardial tissue are hematopoietic stem cells (HSC) and mesenchymal stem cells (MSC). The aim of this study was to determine the precise origin of the BM cells mobilized by cytokines to repair infarcted myocardium. Here, we used two independent clonal studies; we transplanted genetically marked single HSC or clonal MSC into lethally-irradiated recipient mice, induced MI, treated the mice with G-CSF, and analyzed the cardiac tissues. First, we transplanted single CD34−c-kit+Sca-1+lineage− side population (CD34−KSL-SP) cells or whole BM cells from mice ubiquitously expressing enhanced green fluorescent protein (EGFP) into lethally-irradiated mice, induced myocardial infarction (MI), and treated the animals with G-CSF to mobilize stem cells to the damaged myocardium. At 8 weeks post-MI, from 100 specimens we counted only 3 EGFP+actinin+ cells in myocardium of CD34−KSL-SP cells-transplanted mice, but more than 5,000 EGFP+actinin+ cells in whole BM cell-transplanted mice, suggesting that most of EGFP+actinin+ cells derived from non-hematopoietic BM cells. These results suggested that the major population of cells mobilized from the BM and active in the regeneration of cardiomyocytes was non-hematopoietic in origin. Next, clonally purified mesenchymal stem cells, CMG cells, transfected with a pMLC2v-EGFP plasmid encoding EGFP driven by the myosin light chain promoter were transplanted directly into BM of lethally-irradiated mice, MI was induced, and they were treated with G-CSF. As a result, a number of EGFP+actinin+ cells were observed in the ischemic myocardium, indicating that CMG cells had been mobilized and differentiated into cardiomyocytes. Together, these results suggested that the vast majority of BM-derived cardiomyocytes are of mesenchymal origin.

Derivation of hepato-pancreatic intermediate progenitor cells from a clonal mesenchymal stem cell line of rat bone marrow origin

We have recently established a clonal mesenchymal stem cell line (rBM25/S3) from adult rat bone marrow. The cells have practically unlimited proliferation capacity (over 300 PDL), maintaining multipotency for differentiation. In the present study, we examined the potential for rBM25/S3 cells to differentiate into insulin-secreting cells. When cultured in the presence of HGF and FGF-4 on Matrigel, rBM25/S3 cells expressed genes specific to pancreatic beta-cells as well as those specific to hepatocytes. They still maintained proliferation capacity with a doubling time of approximately 30 h. These hepato-pancreatic intermediate progenitor cells, but not the original undifferentiated rBM25/S3 cells, were induced by the overexpression of PDX-1 to produce significant amounts of insulin in a manner responding to glucose concentration in medium. The present culture system indicates a direction for further studies aimed at the realization of cell transplantation therapy for type I diabetes mellitus.