Human Adipose-Tissue Derived Stromal Cells in Combination with Hypoxia Effectively Support Ex Vivo Expansion of Cord Blood Haematopoietic Progenitors

The optimisation of haematopoietic stem and progenitor cell expansion is on demand in modern cell therapy. In this work, haematopoietic stem/progenitor cells (HSPCs) have been selected from unmanipulated cord blood mononuclear cells (cbMNCs) due to adhesion to human adipose-tissue derived stromal cells (ASCs) under standard (20%) and tissue-related (5%) oxygen. ASCs efficiently maintained viability and supported further HSPC expansion at 20% and 5% O₂. During co-culture with ASCs, a new floating population of differently committed HSPCs (HSPCs-1) grew. This suspension was enriched with СD34⁺ cells up to 6 (20% O₂) and 8 (5% O₂) times. Functional analysis of HSPCs-1 revealed cobble-stone area forming cells (CAFCs) and lineage-restricted colony-forming cells (CFCs). The number of CFCs was 1.6 times higher at tissue-related O₂, than in standard cultivation (20% O₂). This increase was related to a rise in the number of multipotent precursors - BFU-E, CFU-GEMM and CFU-GM. These changes were at least partly ensured by the increased concentration of MCP-1 and IL-8 at 5% O₂. In summary, our data demonstrated that human ASCs enables the selection of functionally active HSPCs from unfractionated cbMNCs, the further expansion of which without exogenous cytokines provides enrichment with CD34⁺ cells. ASCs efficiently support the viability and proliferation of cord blood haematopoietic progenitors of different commitment at standard and tissue-related O₂ levels at the expense of direct and paracrine cell-to-cell interactions.     

Human Umbilical Cord Matrix Mesenchymal Stem Cells Suppress the Growth of Breast Cancer by Expression of Tumor Suppressor Genes

Human and rat umbilical cord matrix mesenchymal stem cells (UCMSC) possess the ability to control the growth of breast carcinoma cells. Comparative analyses of two types of UCMSC suggest that rat UCMSC-dependent growth regulation is significantly stronger than that of human UCMSC. Their different tumoricidal abilities were clarified by analyzing gene expression profiles in the two types of UCMSC. Microarray analysis revealed differential gene expression between untreated naïve UCMSC and those co-cultured with species-matched breast carcinoma cells. The analyses screened 17 differentially expressed genes that are commonly detected in both human and rat UCMSC. The comparison between the two sets of gene expression profiles identified two tumor suppressor genes, adipose-differentiation related protein (ADRP) and follistatin (FST), that were specifically up-regulated in rat UCMSC, but down-regulated in human UCMSC when they were co-cultured with the corresponding species’ breast carcinoma cells. Over-expression of FST, but not ADRP, in human UCMSC enhanced their ability to suppress the growth of MDA-231 cells. The growth of MDA-231 cells was also significantly lower when they were cultured in medium conditioned with FST, but not ADRP over-expressing human UCMSC. In the breast carcinoma lung metastasis model generated with MDA-231 cells, systemic treatment with FST-over-expressing human UCMSC significantly attenuated the tumor burden. These results suggest that FST may play an important role in exhibiting stronger tumoricidal ability in rat UCMSC than human UCMSC and also implies that human UCMSC can be transformed into stronger tumoricidal cells by enhancing tumor suppressor gene expression.     

Phenotypic and Immunomodulatory Properties of Equine Cord Blood-Derived Mesenchymal Stromal Cells

Multipotent mesenchymal stromal cells (MSC) have attracted interest for their cytotherapeutic potential, partly due to their immunomodulatory abilities. The aim of this study was to test the robustness of our equine cord blood (CB) MSC isolation protocol, to characterize the CB-MSC before and after cryopreservation, and to evaluate their immunosuppressive phenotype. We hypothesized that MSC can be consistently isolated from equine CB, have unique and reproducible marker expression and in vitro suppress lymphoproliferation. Preliminary investigation of constitutive cytoplasmic Toll-like receptor (TLR) 3 and 4 expression was also preformed due to their possible association with anti- or pro-inflammatory MSC phenotypes, respectively. Surface markers were assessed for antigen and mRNA expression by flow cytometry and quantitative polymerase chain reaction (qPCR). Immunomodulatory properties were evaluated in mixed lymphocyte reaction assays, and TLR3 and TLR4 expression were measured by qPCR and immunocytochemistry (ICC). CB-MSC were isolated from each off nine cord blood samples. CB-MSC highly expressed CD29, CD44, CD90, and lacked or had low expression of major histocompatibility complex (MHC) class I, MHC-II, CD4, CD8, CD11a/18 and CD73 before and after cryopreservation. CB-MSC suppressed in vitro lymphoproliferation and constitutively expressed TLR4. Our findings confirmed CB as a reliable MSC source, provides an association of surface marker phenotype and mRNA expression and suggest anti-inflammatory properties of CB-MSC. The relationship between TLRs and lymphocyte function warrants further investigation.     

IFN—α对人脐带间充质干细胞粘附分子表达的影响

目的：本研究旨在观察不同浓度IFN-α对体外培养人脐带问充质千细胞表面粘附分子表达变化的影响。方法!采用组织块移行法培养人脐带间充质干细胞（Humanumbilicalcordmesenchymalstemcells,hucMSCs）,并进行干细胞表面抗原、成骨和成脂鉴定。向P3代hucMSCs加入不同浓度的IFN-α,24小时后收集细胞,应用流式细胞仪检测CD44、CD49d、CD54、CD58、CD62p、CD62L、CD102及CD106等八种粘附分子的表达情况。结果：①生理状态下,CD106、CD62P、CD62L和CD102阳性表达率极低（均〈1％）,CD54表达最高,为41．58％,经IFN-α干预后,CDl02、CDl06、CD62L、CD62p阳性表达率略有升高,但总体变化不明显（均〈5％）。②CD49d、CD54、CD58阳性表达率与IFN-α呈浓度依赖性,最高达（66．36＋2．48）％、（76．26＋1．85）％、（47．78＋O．44）％;CD44在浓度为3×103U／ml时阳性表达率最高,为（49．81±3．25）％,且干预组与对照组、各组间比较差异有显著性意义（P〈0．05）。结论：炎症因子IFN-α可显著提高hucMSCs表面CD54、CD58、CD44、CD49d的阳性表达率,但对CD102、CD106、CD62P和CD62L作用不明显。     

IFN-α对人脐带间充质干细胞粘附分子表达的影响

目的:本研究旨在观察不同浓度IFN-α对体外培养人脐带间充质干细胞表面粘附分子表达变化的影响.方法:采用组织块移行法培养人脐带间充质干细胞(Human umbilical cord mesenchymal stem cells,hucMSCs),并进行干细胞表面抗原、成骨和成脂鉴定.向P3代hucMSCs加入不同浓度的IFN-αt,24小时后收集细胞,应用流式细胞仪检测CD44、CD49d、CD54、CD58、CD62p、CD62L、CD102及CD106等八种粘附分子的表达情况.结果:①生理状态下,CD106、CD62P、CD62L和CD102阳性表达率极低(均＜1％),CD54表达最高,为41.58％,经FN-α干预后,CD102、CD106、CD62L、CD62p阳性表达率略有升高,但总体变化不明显(均＜5％).②CD49d、CD54、CD58阳性表达率与IFN-α呈浓度依赖性,最高达(66.36± 2.48)％、(76.26±1.85)％、(47.78±0.44)％;CD44在浓度为3x 103U/ml时阳性表达率最高,为(49.81±3.25)％,且干预组与对照组、各组间比较差异有显著性意义(P＜0.05).结论:炎症因子IFN-α可显著提高hucMSCs表面CD54、CD58、CD44、CD49d的阳性表达率,但对CD102、CD106、CD62P和CD62L作用不明显.     

Proteomic Analysis of the Extracellular Matrix Produced by Mesenchymal Stromal Cells: Implications for Cell Therapy Mechanism

Mesenchymal stromal cells (MSCs) transiently transfected with notch1 intracellular domain (NICD) are beneficial for neurological disorders as observed in several preclinical studies. Extracellular matrix (ECM) derived from NICD-transfected MSCs has been previously shown to support in vitro neural cell growth and survival better than that of un-transfected MSCs. To understand the underlying mechanism(s) by which NICD-transfected MSC-derived ECM supports neural cell growth and survival, we investigated the differences in NICD-transfected MSC- and MSC-derived ECM protein quantity and composition. To compare the ECM derived from MSCs and NICD-transfected MSCs, the proteins were sequentially solubilized using sodium dodecyl sulfate (SDS) and urea, quantified, and compared across four human donors. We then analyzed ECM proteins using either in-gel digests or in-solution surfactant-assisted trypsin digests (SAISD) coupled with reverse phase nano-liquid chromatography and tandem mass spectrometry (nLC-MS/MS). Analyses using nLC-MS/MS identified key components of ECM from NICD-transfected MSCs and un-transfected MSCs and revealed significant differences in their respective compositions. This work provides a reproducible method for identifying and comparing in vitro cell-derived ECM proteins, which is crucial for exploring the mechanisms underlying cellular therapy.     

Endothelial Cell-Selective Adhesion Molecule Expression in Hematopoietic Stem/Progenitor Cells Is Essential for Erythropoiesis Recovery after Bone Marrow Injury

Numerous red blood cells are generated every second from proliferative progenitor cells under a homeostatic state. Increased erythropoietic activity is required after myelo-suppression as a result of chemo-radio therapies. Our previous study revealed that the endothelial cell-selective adhesion molecule (ESAM), an authentic hematopoietic stem cell marker, plays essential roles in stress-induced hematopoiesis. To determine the physiological importance of ESAM in erythroid recovery, ESAM-knockout (KO) mice were treated with the anti-cancer drug, 5-fluorouracil (5-FU). ESAM-KO mice experienced severe and prolonged anemia after 5-FU treatment compared to wild-type (WT) mice. Eight days after the 5-FU injection, compared to WT mice, ESAM-KO mice showed reduced numbers of erythroid progenitors in bone marrow (BM) and spleen, and reticulocytes in peripheral blood. Megakaryocyte-erythrocyte progenitors (MEPs) from the BM of 5-FU-treated ESAM-KO mice showed reduced burst forming unit-erythrocyte (BFU-E) capacities than those from WT mice. BM transplantation revealed that hematopoietic stem/progenitor cells from ESAM-KO donors were more sensitive to 5-FU treatment than that from WT donors in the WT host mice. However, hematopoietic cells from WT donors transplanted into ESAM-KO host mice could normally reconstitute the erythroid lineage after a BM injury. These results suggested that ESAM expression in hematopoietic cells, but not environmental cells, is critical for hematopoietic recovery. We also found that 5-FU treatment induces the up-regulation of ESAM in primitive erythroid progenitors and macrophages that do not express ESAM under homeostatic conditions. The phenotypic change seen in macrophages might be functionally involved in the interaction between erythroid progenitors and their niche components during stress-induced acute erythropoiesis. Microarray analyses of primitive erythroid progenitors from 5-FU-treated WT and ESAM-KO mice revealed that various signaling pathways, including the GATA1 system, were impaired in ESAM-KO mice. Thus, our data demonstrate that ESAM expression in hematopoietic progenitors is essential for erythroid recovery after a BM injury.     

Hypoxic Preconditioning Increases Survival and Pro-Angiogenic Capacity of Human Cord Blood Mesenchymal Stromal Cells In Vitro

Hypoxic preconditioning was shown to improve the therapeutic efficacy of bone marrow-derived multipotent mesenchymal stromal cells (MSCs) upon transplantation in ischemic tissue. Given the interest in clinical applications of umbilical cord blood-derived MSCs, we developed a specific hypoxic preconditioning protocol and investigated its anti-apoptotic and pro-angiogenic effects on cord blood MSCs undergoing simulated ischemia in vitro by subjecting them to hypoxia and nutrient deprivation with or without preceding hypoxic preconditioning. Cell number, metabolic activity, surface marker expression, chromosomal stability, apoptosis (caspases-3/7 activity) and necrosis were determined, and phosphorylation, mRNA expression and protein secretion of selected apoptosis and angiogenesis-regulating factors were quantified. Then, human umbilical vein endothelial cells (HUVEC) were subjected to simulated ischemia in co-culture with hypoxically preconditioned or naïve cord blood MSCs, and HUVEC proliferation was measured. Migration, proliferation and nitric oxide production of HUVECs were determined in presence of cord blood MSC-conditioned medium. Cord blood MSCs proved least sensitive to simulated ischemia when they were preconditioned for 24 h, while their basic behavior, immunophenotype and karyotype in culture remained unchanged. Here, “post-ischemic” cell number and metabolic activity were enhanced and caspase-3/7 activity and lactate dehydrogenase release were reduced as compared to non-preconditioned cells. Phosphorylation of AKT and BAD, mRNA expression of BCL-XL, BAG1 and VEGF, and VEGF protein secretion were higher in preconditioned cells. Hypoxically preconditioned cord blood MSCs enhanced HUVEC proliferation and migration, while nitric oxide production remained unchanged. We conclude that hypoxic preconditioning protects cord blood MSCs by activation of anti-apoptotic signaling mechanisms and enhances their angiogenic potential. Hence, hypoxic preconditioning might be a translationally relevant strategy to increase the tolerance of cord blood MSCs to ischemia and improve their therapeutic efficacy in clinical applications.     

Suspension Medium Influences Interaction of Mesenchymal Stromal Cells with Endothelium and Pulmonary Toxicity after Transplantation In Mice

Intravenous (i.v.) transplantation and subsequent homing of Mesenchymal Stromal Cells (MSC) may be adversely influenced by their relatively high adhesion capacity and their tendency to aggregate, leading to clogging of capillaries especially in the lungs. We evaluated the ability of murine MSC suspended in EDTA or heparin in buffered saline solution on their spontaneous adhesion to endothelial cells in vitro, under shear stress and their in vivo tolerability after i.v. injection. We show that suspension of MSC in heparin was highly beneficial, avoiding clinical symptoms in 95% of mice, whereas application of MSC suspended in PBS/EDTA or control buffer caused severe pulmonary reactions and partly, death. In vitro studies using parallel plate flow chambers revealed increased adhesion of MSC suspended in PBS/EDTA to endothelial cells compared with MSC in PBS/heparin. These data provide a means to predict and to interfere with toxicity of i.v. transplanted MSC.     

Increased Proliferation and Analysis of Differential Gene Expression in Human Wharton's Jelly-derived Mesenchymal Stromal Cells under Hypoxia

Multipotent mesenchymal stromal cells (MSCs) from Wharton''s jelly (WJ) of umbilical cord bear higher proliferation rate and self-renewal capacity than adult tissue-derived MSCs and are a primitive stromal cell population. Stem cell niche or physiological microenvironment plays a crucial role in maintenance of stem cell properties and oxygen concentration is an important component of the stem cell niche. Low oxygen tension or hypoxia is prevalent in the microenvironment of embryonic stem cells and many adult stem cells at early stages of development. Again, in vivo, MSCs are known to home specifically to hypoxic events following tissue injuries. Here we examined the effect of hypoxia on proliferation and in vitro differentiation potential of WJ-MSCs. Under hypoxia, WJ-MSCs exhibited improved proliferative potential while maintaining multi-lineage differentiation potential and surface marker expression. Hypoxic WJ-MSCs expressed higher mRNA levels of hypoxia inducible factors, notch receptors and notch downstream gene HES1. Gene expression profile of WJ-MSCs exposed to hypoxia and normoxia was compared and we identified a differential gene expression pattern where several stem cells markers and early mesodermal/endothelial genes such as DESMIN, CD34, ACTC were upregulated under hypoxia, suggesting that in vitro culturing of WJ-MSCs under hypoxic conditions leads to adoption of a mesodermal/endothelial fate. Thus, we demonstrate for the first time the effect of hypoxia on gene expression and growth kinetics of WJ-MSCs. Finally, although WJ-MSCs do not induce teratomas, under stressful and long-term culture conditions, MSCs can occasionally undergo transformation. Though there were no chromosomal abnormalities, certain transformation markers were upregulated in a few of the samples of WJ-MSCs under hypoxia.     

Differential Effects of EGF and Amphiregulin on Adhesion Molecule Expression and Migration of Colon Carcinoma Cells

Epidermal growth factor (EGF) is a potent morphogen affecting cell shape and motility through regulation of adhesive interactions. We have characterized the morphological effects of EGF on GP2d and GP5d colon carcinoma cell lines and have compared the ability of the heparin-binding EGF receptor ligand amphiregulin (AR) to elicit the same effects. EGF induced a marked epithelial–mesenchymal transition in both cell lines. This effect was evident at 7 pMEGF and was associated with a reduction in cellular adherens junctions and diminished cell–cell contact; it was also associated with an increase in expression of α2-integrin as well as enhanced adhesion to the substratum and cell spreading. These changes in adhesion molecule expression were accompanied by enhanced migration on collagen. Blockade of cell growth with mitomycin C did not prevent the EGF-induced morphological change, showing that the mitogenic and morphogenic responses of the GP cells were separable. The phosphatidyl inositol (PI) 3-kinase inhibitor wortmannin inhibited basal proliferation but had no effect on the EGF-induced morphological change, further suggesting that the PI 3-kinase pathway was not involved in the morphogenic response of these cells. Amphiregulin stimulated proliferation of both cell lines, but could only elicit a modest morphological change if used at considerably higher doses or if growth was blocked with mitomycin C. In cells treated with 55 nMAR, α₂-integrin expression was slightly increased; however, unlike the EGF case, adherens junctions remained intact. These differences in the ability of EGF and amphiregulin to affect cellular adhesion and migration may be significant factors influencing normal and tumor cell behavior.     

Perfusion of isolated rat kidney with Mesenchymal Stromal Cells/Extracellular Vesicles prevents ischaemic injury

Kidney donation after circulatory death (DCD) is a less than ideal option to meet organ shortages. Hypothermic machine perfusion (HMP) with Belzer solution (BS) improves the viability of DCD kidneys, although the graft clinical course remains critical. Mesenchymal stromal cells (MSC) promote tissue repair by releasing extracellular vesicles (EV). We evaluated whether delivering MSC‐/MSC‐derived EV during HMP protects rat DCD kidneys from ischaemic injury and investigated the underlying pathogenic mechanisms. Warm ischaemic isolated kidneys were cold‐perfused (4 hrs) with BS, BS supplemented with MSC or EV. Renal damage was evaluated by histology and renal gene expression by microarray analysis, RT‐PCR. Malondialdehyde, lactate, LDH, glucose and pyruvate were measured in the effluent fluid. MSC‐/EV‐treated kidneys showed significantly less global ischaemic damage. In the MSC/EV groups, there was up‐regulation of three genes encoding enzymes known to improve cell energy metabolism and three genes encoding proteins involved in ion membrane transport. In the effluent fluid, lactate, LDH, MDA and glucose were significantly lower and pyruvate higher in MSC/EV kidneys as compared with BS, suggesting the larger use of energy substrates by MSC/EV kidneys. The addition of MSC/EV to BS during HMP protects the kidney from ischaemic injury by preserving the enzymatic machinery essential for cell viability and protects the kidney from reperfusion damage.     

Post-Thaw Non-Cultured and Post-Thaw Cultured Equine Cord Blood Mesenchymal Stromal Cells Equally Suppress Lymphocyte Proliferation In Vitro

Multipotent mesenchymal stromal cells (MSC) are receiving increased attention for their non-progenitor immunomodulatory potential. Cryopreservation is commonly used for long-term storage of MSC. Post-thaw MSC proliferation is associated with a lag-phase in vitro. How this lag-phase affect MSC immunomodulatory properties is unknown. We hypothesized that in vitro there is no difference in lymphocyte suppression potential between quick-thawed cryopreserved equine cord blood (CB) MSC immediately included in mixed lymphocyte reaction (MLR) and same MSC allowed post-thaw culture time prior to inclusion in MLR. Cryopreserved CB-MSC from five unrelated foals were compared using two-way MLR. For each of the five unrelated MSC cultures, paired MLR assays of MSC allowed five days of post-thaw culture and MSC included in MLR assay immediately post-thawing were evaluated. We report no difference in the suppression of lymphocyte proliferation by CB-MSC that had undergone post-thaw culture and MSC not cultured post-thaw (p<0.0001). Also, there was no inter-donor variability between the lymphocyte suppressive properties of MSC harvested from the five different donors (p = 0.13). These findings suggest that cryopreserved CB-MSC may have clinical utility immediately upon thawing. One implication hereof is the possibility of using cryopreserved CB-MSC at third party locations without the need for cell culture equipment or competencies.     

The Identification of Marker Genes for Predicting the Osteogenic Differentiation Potential of Mesenchymal Stromal Cells

Mesenchymal stromal cells (MSCs) have the potential to differentiate into a variety of mature cell types and are a promising source of regenerative medicine. The success of regenerative medicine using MSCs strongly depends on their differentiation potential. In this study, we sought to identify marker genes for predicting the osteogenic differentiation potential by comparing ilium MSC and fibroblast samples. We measured the mRNA levels of 95 candidate genes in nine ilium MSC and four fibroblast samples before osteogenic induction, and compared them with alkaline phosphatase (ALP) activity as a marker of osteogenic differentiation after induction. We identified 17 genes whose mRNA expression levels positively correlated with ALP activity. The chondrogenic and adipogenic differentiation potentials of jaw MSCs are much lower than those of ilium MSCs, although the osteogenic differentiation potential of jaw MSCs is comparable with that of ilium MSCs. To select markers suitable for predicting the osteogenic differentiation potential, we compared the mRNA levels of the 17 genes in ilium MSCs with those in jaw MSCs. The levels of 7 out of the 17 genes were not substantially different between the jaw and ilium MSCs, while the remaining 10 genes were expressed at significantly lower levels in jaw MSCs than in ilium MSCs. The mRNA levels of the seven similarly expressed genes were also compared with those in fibroblasts, which have little or no osteogenic differentiation potential. Among the seven genes, the mRNA levels of IGF1 and SRGN in all MSCs examined were higher than those in any of the fibroblasts. These results suggest that measuring the mRNA levels of IGF1 and SRGN before osteogenic induction will provide useful information for selecting competent MSCs for regenerative medicine, although the effectiveness of the markers is needed to be confirmed using a large number of MSCs, which have various levels of osteogenic differentiation potential.     

Stromal Fibroblasts Mediate Extracellular Matrix Remodeling and Invasion of Scirrhous Gastric Carcinoma Cells

Scirrhous gastric carcinoma (SGC) has the worst prognosis of all gastric cancers, owing to its rapid expansion by invasion and frequent peritoneal dissemination. Due to the increased proliferation of stromal fibroblasts (SFs) that occurs within SGC lesions and the peritoneal metastatic sites, SFs have been proposed to support the progression of this disease. However, the biological and molecular basis and the pathological role of the intercellular interaction between SGC cells and SFs remain largely unknown. In this study, we investigated the role of SFs in the invasion of the extracellular matrix (ECM) by SGC cells. When SGC cells were cocultured with SFs derived from SGC tissue on three-dimensional (3D) Matrigel, they were attracted together to form large cellular aggregates that invaded within the Matrigel. Time-lapse imaging revealed that this process was associated with extensive contraction and remodeling of the ECM. Immunofluorescence and biochemical analysis showed that SGC cells stimulate phosphorylation of myosin light chain and actomyosin-mediated mechanical remodeling of the ECM by SFs. By utilizing this assay system for inhibitor library screening, we have identified several inhibitors that potently suppress the cooperation between SGC cells and SFs to form the invasive structures. Among them, a Src inhibitor dasatinib impaired the interaction between SGC cells and SFs both in vitro and in vivo and effectively blocked peritoneal dissemination of SGC cells. These results indicate that SFs mediate mechanical remodeling of the ECM by SGC cells, thereby promoting invasion and peritoneal dissemination of SGC.     

Effects of Bone Marrow Mesenchymal Stem Cells on Hematopoietic Recovery and Acute Graft-Versus-Host Disease in Murine Allogeneic Umbilical Cord Blood Transplantation Model

To investigate the effect of bone marrow mesenchymal stem cells (MSC) on hematopoietic recovery and acute graft-versus-host disease (GVHD) in a murine allogeneic umbilical cord blood transplantation (allo-UCBT) model. MSCs were obtained from C57/BL mouse bone marrow. The MSC phenotypes were identified by flow cytometry (FCM), and their ability to differentiate into osteoblasts and adipocytes was tested. Once murine allo-UCBT and aGVHD models were established, mice were divided into five groups: (1) total body irradiation (TBI) group, each mouse receiving 0.3 ml sterile saline infusion after TBI and used as control; (2) UCB group, receiving 2 × 10⁶ umbilical cord blood mononuclear cells (UCB-MNC) after TBI; (3) UCB+MSC group, receiving 2 × 10⁶ UCB-MNC and 2 × 10⁷ MSC after TBI; (4) UCB+SC group, receiving 2 × 10⁶ UCB-MNC and 2 × 10⁶ spleen cells after TBI; and (5) UCB+SC+MSC group, receiving 2 × 10⁶ UCB-MNC, 2 × 10⁷ MSC and 2 × 10⁶ spleen cells after TBI. To evaluate the engraftment of HSC, the white blood cells, red blood cells, and platelets counts were tested at different time points after transplantation, and the ratio of chimerism was identified by FCM. The acute GVHD clinical scores, recipient mice survival, and the histopathological analyses were used to evaluate the effect of MSC on acute GVHD. MSCs were successfully obtained in vitro and FCM analysis showed that these cells are highly positive for CD90.2, CD44, and negative for CD34, CD45, and they are capable to differentiate into osteoblasts and adipocytes after being induced. Compared to UCB group, the UCB+MSC mice had shorter duration of myelosuppression and higher percentage of donor-derived cells which was up to 22.87 ± 4.3 % and the white blood cell (WBC), red blood cell (RBC), and platelet counts started to increase by day 6 after transplantation. Moreover, the average survival time for UCB+MSC mice was 25.0 ± 10.55 days, while for the UCB group it was 15.5 ± 12.50 days. The UCB+SC mice showed fatigue, loss of appetite, weight loss, arched back, and hair ruffling on day 13 post transplantation. Approximately 50 % of mice showed skin ulcers, had diarrhea and other manifestations of acute GVHD, and all mice were died within 20 days. Histopathological analysis confirmed grade II–IV GVHD manifestation. In addition to transient weight loss, some UCB+SC+MSC mice developed arched back, hair ruffling, diarrhea and other manifestations of acute GVHD. The clinical scores in UCB+SC+MSC mice with acute GVHD (grade I–II or without GVHD) were lower than UCB+SC group (P < 0.05). Bone marrow MSCs can promote hematopoietic recovery and decrease the incidence of acute GVHD in murine allo-UCBT model.     

Differential Sensitivity of Epithelial Cells to Extracellular Matrix in Polarity Establishment

Establishment of apical-basal polarity is crucial for epithelial sheets that form a compartment in the body, which function to maintain the environment in the compartment. Effects of impaired polarization are easily observed in three-dimensional (3-D) culture systems rather than in two-dimensional (2-D) culture systems. Although the mechanisms for establishing the polarity are not completely understood, signals from the extracellular matrix (ECM) are considered to be essential for determining the basal side and eventually generating polarity in the epithelial cells. To elucidate the common features and differences in polarity establishment among various epithelial cells, we analyzed the formation of epithelial apical-basal polarity using three cell lines of different origin: MDCK II cells (dog renal tubules), EpH4 cells (mouse mammary gland), and R2/7 cells (human colon) expressing wild-type α-catenin (R2/7 α-Cate cells). These cells showed clear apical-basal polarity in 2-D cultures. In 3-D cultures, however, each cell line displayed different responses to the same ECM. In MDCK II cells, spheroids with a single lumen formed in both Matrigel and collagen gel. In R2/7 α-Cate cells, spheroids showed similar apical-basal polarity as that seen in MDCK II cells, but had multiple lumens. In EpH4 cells, the spheroids displayed an apical-basal polarity that was opposite to that seen in the other two cell types in both ECM gels, at least during the culture period. On the other hand, the three cell lines showed the same apical-basal polarity both in 2-D cultures and in 3-D cultures using the hanging drop method. The three lines also had similar cellular responses to ECM secreted by the cells themselves. Therefore, appropriate culture conditions should be carefully determined in advance when using various epithelial cells to analyze cell polarity or 3-D morphogenesis.     

Purmorphamine Promotes Matrix Mineralization and Cytoskeletal Changes in Human Umbilical Cord Mesenchymal Stem Cells

Human Umbilical Cord Mesenchymal Stem Cells (hUCMSCs) were subjected to in vitro osteogenic differentiation using a novel combination of signaling molecules including BMP-2 and purmorphamine. Differentiation outcomes were assessed by calcein staining and by microscopic examination of the cytoskeleton. Calcein staining showed appreciable degree of calcium mineralization in cell culture, and changes in the morphological attributes of differentiating cells were observed vis-a-vis the actin cytoskeleton. Finally, positive calcein staining, altered cytoskeletal profile, and stress fiber formation in treated cells demonstrated, for the first time, a potentially synergistic interplay between BMP-2 and the hedgehog agonist, purmorphamine. This study lends support to the notion of combining small doses of potent molecules that can act as safe, less toxic inducers of osteogenic differentiation of human umbilical cord mesenchymal stem cells with respect to bone regeneration.     

Transplantation of Human Skin-Derived Mesenchymal Stromal Cells Improves Locomotor Recovery After Spinal Cord Injury in Rats

Spinal cord injury (SCI) is a devastating neurologic disorder with significant impacts on quality of life, life expectancy, and economic burden. Although there are no fully restorative treatments yet available, several animal and small-scale clinical studies have highlighted the therapeutic potential of cellular interventions for SCI. Mesenchymal stem cells (MSCs)—which are conventionally isolated from the bone marrow—recently emerged as promising candidates for treating SCI and have been shown to provide trophic support, ameliorate inflammatory responses, and reduce cell death following the mechanical trauma. Here we evaluated the human skin as an alternative source of adult MSCs suitable for autologous cell transplantation strategies for SCI. We showed that human skin-derived MSCs (hSD-MSCs) express a range of neural markers under standard culture conditions and are able to survive and respond to neurogenic stimulation in vitro. In addition, using histological analysis and behavioral assessment, we demonstrated as a proof-of-principle that hSD-MSC transplantation reduces the severity of tissue loss and facilitates locomotor recovery in a rat model of SCI. Altogether, the study provides further characterization of skin-derived MSC cultures and indicates that the human skin may represent an attractive source for cell-based therapies for SCI and other neurological disorders. Further investigation is needed to elucidate the mechanisms by which hSD-MSCs elicit tissue repair and/or locomotor recovery.