Inhibition of Notch Signaling Promotes the Adipogenic Differentiation of Mesenchymal Stem Cells Through Autophagy Activation and PTEN-PI3K/AKT/mTOR Pathway.

BACKGROUND: The Notch signaling pathway is implicated in a broad range of developmental processes, including cell fate decisions. This study was designed to determine the role of Notch signaling in adipogenic differentiation of human bone marrow derived MSCs (BM-MSCs). METHODS: The Notch signaling was inhibited by the γ-secretase inhibitor N-[N-(3,5-difluor- ophenacetyl-L-alanyl)]-S-phenylglycine t-butylester (DAPT). The markers involving adipogenic differentiation of MSCs, the relative pathway PTEN-PI3K/Akt/mTOR and autophagy activation were then analyzed. Furthermore, the autophagy inhibitor chloroquine (CQ) and 3-methyladenine (3-MA) were used to study the role of autophagy in the DAPT-induced the adipogenic differentiation of MSCs. RESULTS: We first confirmed the down -regulation of Notch gene expression during MSCs adipocyte differentiation, and showed that the inhibition of Notch signaling significantly enhanced adipogenic differentiation of MSCs. Furthermore, Notch inhibitor DAPT induced early autophagy by acting on PTEN-PI3K/Akt/mTOR pathway. The autophagy inhibitor CQ and 3-MA dramatically abolished the effects of DAPT-induced autophagy and adipogenic differentiation of MSCs. CONCLUSION: Our results indicate that inhibition of Notch signaling could promote MSCs adipogenesis mediated by autophagy involving PTEN-PI3K/Akt/mTOR pathway. Notch signaling could be a novel target for regulating the adipogenic differentiation of MSCs.

Serum-free media and the immunoregulatory properties of mesenchymal stem cells in vivo and in vitro.

BACKGROUND: Mesenchymal stem cells are capable of self-renewal and multi-lineage differentiation. They are used extensively to treat several diseases. Traditionally, mesenchymal stem cells are cultured in serum-containing media, typically supplemented with fetal bovine serum (FBS). However, the variability of FBS is likely to skew experimental results. Although serum-free media used to expand mesenchymal stem cells has facilitated remarkable achievements, immunomodulation of these cells in under serum-free conditions is poorly understood. We hypothesized that mesenchymal stem cells expanded in serum-free media will retain powerful immunoregulatory functions in vitro and in vivo. DESIGN AND METHODS: Immunosuppressive activity and the immunomodulatory cytokines produced by mesenchymal stem cells in serum-free media were characterized in vitro. Immunomodulation by serum-free mesenchymal stem cell expansion in monocrotaline-induced pulmonary hypertension was explored in vivo. RESULTS: Similar to cells in serum-containing media, mesenchymal stem cells expanded in serum-free media inhibited proliferation and apoptosis of CD4(+)T cells. They also exhibited strong immunosuppressive activities and secreted high levels of immunomodulatory cytokines such as PGE2, IDO1, COX2, IL-6, and IL-1ß, but not HGF. On the other hand, growth of mesenchymal stem cells in serum-free media attenuated pulmonary vascular remodeling and inhibited mRNA expression of proinflammatory cytokines TNF-α, IFN-γ, IL-6, IL-1ß, and IL-18. CONCLUSIONS: Mesenchymal stem cells in serum-free media maintained powerful immunomodulatory function in vitro and in vivo; serum-free media may replace serum-containing media for basic research and clinical applications.

MicroRNA-124 suppresses breast cancer cell growth and motility by targeting CD151.

BACKGROUND: CD151 is highly expressed in breast cancer cells and has been shown to accelerate breast cancer by enhancing cell growth and motility, but its regulation is poorly understood. To explore post-translation regulation of CD151, for example microRNAs, will be of great importance to claim the mechanism. METHODS: A luciferase reporter assay was used to determine whether CD151 was a target of miR-124. The levels of CD151 mRNA were detected by real-time PCR and CD151 protein expression was measured by western blot and flow cytometry. The effects of miR-124 expression on growth, apoptosis, cell cycle and motility of breast cancer cells were determined. RESULTS: We discovered that miR-124 directly targets the 3' untranslated region (3'-UTR) of CD151 mRNAs and suppresses its mRNA expression and protein translation. Both siRNA of CD151 and miR-124 mimics could significantly inhibit proliferation of breast cancer cell lines via cell cycle arrest but does not induce apoptosis. Meanwhile, miR-124 mimics significantly inhibited the motility of breast cancer cells. CONCLUSION: miR-124 plays a critical role in inhibiting the invasive and metastatic potential of breast cancer cells, probably by directly targeting the CD151 genes. Our findings highlight an important role of miR-124 in the regulation of invasion and metastasis by breast cancer cells and suggest a potential application for miR-124 in breast cancer treatment.

Mesenchymal stem cells support proliferation and terminal differentiation of B cells.

BACKGROUND: Mesenchymal stem cells (MSC) play important roles in modulating the activities of T lymphocytes, dendritic cells and natural killer cells. These immunoregulatory properties of MSC suggest their therapeutic potential in autoimmune diseases. However, the effects of MSC on B cells are still poorly understood. The present study was designed to investigate the interaction between MSC and B cells both in vitro and in vivo, and to determine the possible mechanism of action. DESIGN AND METHOD: The effect of human umbilical cord mesenchymal stem cells (UC-MSC) on proliferation and differentiation of B-cells were characterized in vitro, and we also tested the immunoregulatory properties of mouse bone marrow MSC (BM-MSC) on T cell dependent and independent antibody production in vivo in mice. RESULTS: Treatment with human UC-MSC resulted in an increase of proliferation, differentiation of B cells into plasma cells and production of antibodies in vitro. Mouse BM-MSC significantly enhanced T cell dependent and independent antibodies production in vivo in mice. PGE2 partially mediated the immunosuppressive activity of human UC-MSC but IL-6 did not regulate this activity. CONCLUSION: MSC promote proliferation and differentiation of B cells in vitro and in vivo partially through PGE2 but not IL-6.

IL-6 production stimulated by CD14(+) monocytes-paracrined IL-1ß does not contribute to the immunosuppressive activity of human umbilical cord mesenchymal stem cells.

BACKGROUND/AIMS: Human umbilical cord mesenchymal stem cells (hUC-MSCs) possess immunosuppressive activities but the mechanisms of such activities are not fully understood. Here, we investigated the role of IL-6, one of the characteristic factors of MSCs, in the immunoregulating effect of hUC-MSCs on CD4(+) T lymphocytes. METHODS: The condition media from human peripheral blood mononuclear cells (hPBMCs) or CD14+/- cell were tested if stimulating IL-6 production by hUC-MSCs. The related signaling pathway of IL-6, and the immunosuppressive activity of IL-6 on CD4(+) T lymphocytes were studied. RESULT: IL-6 production was dramatically increased by hUC-MSCs when co-culturing with resting or activated hPBMCs. CD14(+) monocytes-paracrined IL-1ß promoted the secretion of IL-6 by hUC-MSCs via JNK and NF-κB signaling pathway. Blocking of PGE2 synthesis did not affect the secretion of IL-6, anti-IL-6 antibody was not able to reverse hUC-MSCs-mediated inhibition on CD4(+) T lymphocytes. IL-6 did not mediate the suppressive activity of IL-1ß-hUC-MSCs- PGE2 on CD4(+) T cell. CONCLUSION: CD14(+) monocytes-paracrined IL-1ß promotes IL-6 secretion by hUC-MSCs through activating JNK and NF-κB signaling pathway. However, increased IL-6 production does not contribute to immunosuppressive activity of IL-1ß-hUC-MSCs- PGE2 on CD4(+) T cells.

Intrapulmonary delivery of human umbilical cord mesenchymal stem cells attenuates acute lung injury by expanding CD4+CD25+ Forkhead Boxp3 (FOXP3)+ regulatory T cells and balancing anti- and pro-inflammatory factors.

BACKGROUND: Systemic and local inflammatory processes play key, mainly detrimental roles in the pathophysiology of acute lung injury (ALI). The present study was designed to determine whether human umbilical cord mesenchymal stem cells (UCMSC) are able to act on CD4(+)CD25(+) Foxp3(+)Treg cells and lead to an improvement in ALI. METHODS: Mice were administered intratracheally endotoxin (lipopolysaccharide [LPS]) and received intrapulmonary 1×10(6) UCMSC 4 hours after challenge. The CD4(+)CD25(+) Foxp3(+)Treg, survival time, body weight, histology and lung injury scores were assessed after transplantation of UCMSC. In addition, anti-inflammatory factor IL10 and pro-inflammatory mediators production including tumor necrosis factor-a (TNF-α), macrophage inflammatory protein-2(MIP-2) and interferon-γ (IFN-γ) were detected. RESULTS: Transplantation of UCMSC resulted in significant increase in the level of CD4(+)CD25(+) Foxp3(+)Treg in ALI. Increased level of anti-inflammatory factor IL-10 and reduced levels of TNF-α, MIP-2 and IFN-γ were simultaneously observed in ALI in comparison with control mice. CONCLUSION: Our data demonstrate for the first time that transplantation of UCMSC ameliorates ALI by enhancing the diminished levels of alveolar CD4(+)CD25(+) Foxp3(+)Treg and balancing anti- and pro-inflammatory factors in ALI mice.

CD14+ monocytes promote the immunosuppressive effect of human umbilical cord matrix stem cells.

Here, the effect of CD14(+) monocytes on human umbilical cord matrix stem cell (hUC-MSC)-mediated immunosuppression was studied in vitro. hUC-MSCs exerted a potent inhibitory effect on the proliferation and interferon-gamma (IFN-gamma) secretion capacities of CD4(+) and CD8(+) T cells in response to anti-CD3/CD28 stimulation. Transwell co-culture system revealed that the suppressive effect was primarily mediated by soluble factors. Addition of prostaglandin synthesis inhibitors (indomethacin or NS-398) almost completely abrogated the immunosuppression activity of hUC-MSCs, identifying prostaglandin E(2) (PGE(2)) as an important soluble mediator. CD14(+) monocytes were found to be able to enhance significantly the immunosuppressive effect of hUC-MSCs in a dose-dependent fashion. Moreover, the inflammatory cytokine IL-1beta, either exogenously added or produced by CD14(+) monocytes in culture, could trigger expression of high levels of PGE(2) by hUC-MSCs, whereas inclusion of the IL-1 receptor antagonist (IL-1RA) in the culture down-regulated not only PGE(2) expression, but also reversed the promotional effect of CD14(+) monocytes and partially restored CD4(+) and CD8(+) T cell proliferation and IFN-gamma secretion. Our data demonstrate an important role of monocytes in the hUC-MSC-induced immunomodulation, which may have important implications in future efforts to explore the clinical potentials of hUC-MSCs.

Safety and Efficacy of Placenta-Derived Mesenchymal Stem Cell Treatment for Diabetic Patients with Critical Limb Ischemia: A Pilot Study.

AIM: Diabetic foot has become the main cause of non-traumatic amputation. Stem cell therapy, especially mesenchymal stem cells (MSCs), holds a great promise as a therapy for diabetic foot with ischemia limb arterial disease. The aim of this pilot study is to evaluate the safety and efficacy of placenta-derived MSCs (P-MSCs) treatment for diabetic patients with critical limb ischemia (CLI). METHODS: Four eligible diabetic patients with CLI were consecutively enrolled in this pilot study. On the base of the standard-of-care treatment, these patients accepted P-MSCs treatment by intramuscular injection for successive 3 times at an interval of 4 weeks, and the safety and efficacy of placenta-derived MSCs (P-MSCs) treatment were evaluated. RESULTS: There were no serious adverse events during the period of P-MSCs injection and the 24-weeks follow-up period. The clinical ischemic features of patients were improved 24 weeks after P-MSCs treatment. The scores of resting pain and limb coldness significantly decreased, and pain-free walking distance significantly increased from baseline to 24 weeks after P-MSCs therapy. The resting ankle brachial index increased, but no statistically significant difference was found. The findings of magnetic resonance angiography showed the increase of collateral vessel formation in one patient, but there were no significant changes observed in the other patients. CONCLUSIONS: The data in this pilot study indicated that multiple intramuscular P-MSCs injections may be a safe and effective alternative therapy for diabetic patients with CLI, and larger, placebo-controlled, perspective studies are needed to prove these results.

Human umbilical cord-derived mesenchymal stem cells treatment for refractory uveitis: a case series.

AIM: To evaluate therapeutic outcomes of human umbilical cord-derived mesenchymal stem cells (HUC-MSCs) treatment in patients with refractory uveitis. METHODS: A retrospective and noncomparative review was performed on four patients with refractory uveitis from December 2013 to December 2017. HUC-MSCs were administered intravenously at a dose of 1×106 cells/kg. Clinical response, relapse rate, change of visual acuity, and other metrics were evaluated. RESULTS: All four patients presented with responses to HUC-MSCs treatment, with three males and one female. The numbers of uveitis attacks per year after the HUC-MSCs treatment (0, 2, 0, 0 respectively) all decreased compared with the numbers before the treatment (3, 6, 4, 4 respectively). The oral steroid and immunosuppressive agents were tapered in all patients without recrudescence of ocular inflammation, and three patients discontinued their oral medicine at the last visit. The best corrected visual acuity (BCVA) of 3 patients was improved to varying degrees, and the BCVA of 1 patient remained at 20/20 (Snellen chart) from the first to the last consultation. CONCLUSION: The study provides an effective therapy of HUC-MSCs in maintaining remission in patients affected by uveitis refractory to previous immunosuppressant treatments.

Human umbilical cord mesenchymal stem cells hUC-MSCs exert immunosuppressive activities through a PGE2-dependent mechanism.

Human umbilical-cord-derived mesenchymal stem cells (hUC-MSCs) constitute an attractive alternative to bone-marrow-derived MSCs for potential clinical applications because of easy preparation and lower risk of viral contamination. In this study, both proliferation of human peripheral blood mononuclear cells (hPBMCs) and their IFN-gamma production in response to mitogenic or allogeneic stimulus were effectively inhibited by hUC-MSCs. Co-culture experiments in transwell systems indicated that the suppression was largely mediated by soluble factor(s). Blocking experiments identified prostaglandin E(2) (PGE(2)) as the major factor, because inhibition of PGE(2) synthesis almost completely mitigated the immunosuppressive effects, whereas neutralization of TGF-beta, IDO, and NO activities had little effects. Moreover, the inflammatory cytokines, IFN-gamma and IL-1beta, produced by hPBMCs upon activation notably upregulated the expression of cyclooxygenase-2 (COX-2) and the production of PGE(2) by hUC-MSCs. In conclusion, our data have demonstrated for the first time the PGE(2)-mediated mechanism by which hUC-MSCs exert their immunomodulatory effects.

Hypoxia-inducible factor (HIF)-1 alpha directly enhances the transcriptional activity of stem cell factor (SCF) in response to hypoxia and epidermal growth factor (EGF).

Stem cell factor (SCF) plays important roles in tumor growth and angiogenesis. However, its regulatory mechanism remains largely undefined. Here, we report that hypoxia upregulated the expression of SCF in MCF-7 breast cancer cells in both messenger RNA and protein levels. When hypoxia-inducible factor (HIF)-1 alpha expression was knocked down by RNA interference, the MCF-7 cell expression of SCF was decreased significantly. Furthermore, the SCF receptor, c-kit phosphorylation was significantly strengthened by the condition culture media from hypoxic MCF-7 and MCF-7-c cells. The survival of A549 cells was more dependent on SCF under hypoxia. Analysis of SCF promoter 5'-flanking region revealed a potential hypoxia-response element (HRE; 5'-GCGTG-3') located at -68 to -64 relative to the transcriptional start site. Chromatin immunoprecipitation assay demonstrated that HIF-1 alpha directly bound to this region under normoxia, and this binding activity was significantly enhanced under hypoxia. Overexpression of HIF-1 alpha significantly upregulated the expression of luciferase reporter gene under control of the SCF promoters in both MCF-7 cells and human embryonic kidney 293 cells, but mutation of the HRE site completely blocked this effect. Epidermal growth factor was also able to enhance the SCF expression under normoxia in MCF-7 cells, which was dependent on HIF-1 alpha. Taken together, our data demonstrated that HIF-1 alpha was a key regulator of SCF expression in breast cancer cells. Hypoxia and epidermal growth factor receptor signal coexisted in the tumor microenvironment and might promote angiogenesis through HIF-1 alpha-mediated upregulation of SCF and other angiogenic factors.

Intravenous injection of allogeneic umbilical cord-derived multipotent mesenchymal stromal cells reduces the infarct area and ameliorates cardiac function in a porcine model of acute myocardial infarction.

BACKGROUND: Multipotent mesenchymal stromal cell (MSC) therapy has been widely recognized as a feasible strategy for regenerating injured myocardial tissue. However, little is known about the efficacy of intravenous injection of allogeneic umbilical cord (UC) MSCs in preclinical models of porcine myocardial infarction. METHODS: Different dosages of allogeneic UC-MSCs or the vehicle [phosphate-buffered saline (PBS)] were delivered intravenously into an acute myocardial infarction (AMI) porcine model twice after coronary ligation. Echocardiography was performed to examine the cardiac function and single photon emission computed tomography (SPECT) and positron emission tomography (PET)/computed tomography (CT) was performed to detect cardiac perfusion and nonviable myocardium. At the end of the experiment, 2,3,5-triphenyl-tetrazolium chloride (TTC) staining and Masson T staining were performed to determine the infarct area. The protein and gene expression levels associated with cardiac function, inflammation, and angiogenesis were examined by Western blot and real time polymerase chain reaction (PCR). In vivo trafficking of intravenous injection of allogeneic UC-MSCs enhanced green fluorescent protein (eGFP) was detected by real time PCR and immunofluorescence. RESULTS: After systemic delivery, allogeneic UC-MSCs were largely distributed in the lungs and some in the infracted myocardium. At week 8 following AMI, echocardiography demonstrated significantly improved fractional shortening in the high-dose (1.5 × 106 cells/kg) group. SPECT-PET/CT showed that UC-MSC treatment in both high and low doses markedly ameliorated the left ventricle (LV) infarct area but did not significantly improve the myocardial perfusion defect. LV remodeling was inhibited by UC-MSC therapy, as reflected by a marked reduction in rthe fibrosis area at basal, middle, and apical levels and reduced extracellular matrix deposition in the total myocardial area. Inflammatory biomarkers (tumor necrosis factor alpha and interleukin-6) were reduced and pro-angiogenesis factors (vascular endothelial growth factor and platelet/endothelial cell adhesion molecule 1) were augmented in the myocardial infarct and border area. High-dose UC-MSCs increased the connexin 43 (Cx43) (myocardium preservation) expression in remote area of the LV myocardium after AMI. CONCLUSIONS: Intravenous injection of UC-MSCs is a feasible and effective way to preserve LV function and ameliorate myocardial remodeling in porcine AMI. The cardioprotective effects of UC-MSCs were attributed to paracrine factors that appear to augment angiogenesis, limit inflammation, and preserve Cx43 gap junction.

Interleukin-27 upregulates major histocompatibility complex class II expression in primary human endothelial cells through induction of major histocompatibility complex class II transactivator.

Interleukin-27 (IL-27) is a novel IL-12 family member that plays a critical role in the regulation of T-cell responses. Its immunoregulatory effects on endothelial cells (EC) remain unexplored. Here we show a role for IL-27 in the induction of major histocompatibility complex (MHC) expression in primary human EC. Stimulation of human umbilical vein ECs by IL-27 rapidly induces IFN regulatory factor-1 and dramatically increases the expression of major histocompatibility class II transactivator (CIITA) isoform IV. Expression of this transactivator correlates with increased MHC class II gene expression. IL-27 also enhances expression of MHC class I molecules. Furthermore expression of beta2-microglobulin and transporter associated with antigen processing-1 transcripts increases in response to IL-27. Additional microarray analysis demonstrates that IL-27 significantly upregulates a panel of genes that correlates with immune regulation, including the chemokines CXCL9, CXCL10, and CX3CL1 in human umbilical vein ECs. This first demonstration that both MHC II and I expression are increased in EC after IL-27 stimulation suggests that IL-27 may be important in conferring immune function on vascular endothelium.

[Role of antiapoptotic Bcl-X(L) in megakaryocyte differentiation and maturation].

OBJECTIVE: To investigate the role of antiapoptotic Bcl-x(L) protein in megakaryocyte differentiation and maturation. METHODS: RNA interference was used to block the expression of Bcl-x(L) when K562 cells were induced to differentiate into megakaryocyte (CD61 + cells) by PDBu, and the expression of Bcl-x(L) was evaluated with flow cytometry and reverse transcription polymerase chain reaction (RT-PCR). The CD34 + cell fraction was positively isolated by using the MiniMACS system from normal bone marrow. Immunochemical staining and flow cytometry were used to detect the expression of Bcl-x(L) in the differentiation (CD41 + cells) of CD34 + cells induced by trombopoietin (TPO). RESULTS: Among K562 cells induced by PDBu, the percentage of CD6L + cells rapidly increased in 24 hours and maintained at a high positive level in 72 hours. When exposured to si-Bcl-x(L), the percentage of CD6 1 + cells only slightly increased in 72 hours. The expression of Bcl-x(L) mRNA was significantly decreased after transfection compared with that of control group, and Bcl-x(L) protein expression decreased correspondingly. After the CD34 + bone marrow cells having been treated with TPO for 5 days to 20 days, the Bcl-x(L)-megakaryocytes increased as the culture time prolonged, and there was a strong expression of Bcl-x(L) in immature megakaryocyte and an obviously decreased expression in degenerating megakaryocytes maturation. CONCLUSIONS: Increased expression of antiapoptotic Bcl-x(L) may be essential to mature megakaryocyte. The down-regulation of antiapoptotic Bcl-x(L) in mature megakaryocyte may be crucial to platelets formation.

Human umbilical cord mesenchymal stem cells increase interleukin-9 production of CD4+ T cells.

Mesenchymal stem cells (MSC) are able to differentiate into cells of multiple lineage, and additionally act to modulate the immune response. Interleukin (IL)-9 is primarily produced by cluster of differentiation (CD)4+ T cells to regulate the immune response. The present study aimed to investigate the effect of human umbilical cord derived-MSC (UC-MSC) on IL-9 production of human CD4+ T cells. It was demonstrated that the addition of UC-MSC to the culture of CD4+ T cells significantly enhanced IL-9 production by CD4+ T cells. Transwell experiments suggested that UC-MSC promotion of IL-9 production by CD4+ T cells was dependent on cell-cell contact. Upregulated expression of CD106 was observed in UC-MSC co-cultured with CD4+ T cells, and the addition of a blocking antibody of CD106 significantly impaired the ability of UC-MSC to promote IL-9 production by CD4+ T cells. Therefore, the results of the present study demonstrated that UC-MSC promoted the generation of IL-9 producing cells, which may be mediated, in part by CD106. The findings may act to expand understanding and knowledge of the immune modulatory role of UC-MSC.

ESE3 Inhibits Pancreatic Cancer Metastasis by Upregulating E-Cadherin.

The ETS family transcription factor ESE3 is a crucial element in differentiation and development programs for many epithelial tissues. Here we report its role as a tumor suppressor in pancreatic cancer. We observed drastically lower ESE3 expression in pancreatic ductal adenocarcinomas (PDAC) compared with adjacent normal pancreatic tissue. Reduced expression of ESE3 in PDAC correlated closely with an increase in lymph node metastasis and vessel invasion and a decrease in relapse-free and overall survival in patients. In functional experiments, downregulating the expression of ESE3 promoted PDAC cell motility and invasiveness along with metastasis in an orthotopic mouse model. Mechanistic studies in PDAC cell lines, the orthotopic mouse model, and human PDAC specimens demonstrated that ESE3 inhibited PDAC metastasis by directly upregulating E-cadherin expression at the level of its transcription. Collectively, our results establish ESE3 as a negative regulator of PDAC progression and metastasis by enforcing E-cadherin upregulation. Cancer Res; 77(4); 874-85. ©2016 AACR.

Isolation and characterization of human umbilical cord mesenchymal stem cells with hematopoiesis-supportive function and other potentials.

BACKGROUND AND OBJECTIVES: Adult bone marrow (BM) is the major source of mesenchymal stem cells (MSC) for cell therapy. However, aspiration of BM involves invasive procedures. We isolated MSC from human full term umbilical cord tissues (UC). The biological characteristics of MSC derived from UC (UC-MSC) were further determined and compared with normal adult bone marrow-derived MSC (BM-MSC). DESIGN AND METHODS: MSC were isolated from UC by enzyme digestion and cultured in appropriate growth medium. The isolation efficiency, cell yield, colony-forming unit-fibroblast (CFU-F) frequency, growth kinetics, phenotypic characteristics, multi-lineage differentiation capacity, cytokine spectrum as well as hematopoiesis-supportive function of UC-MSC were determined and compared with those of BM-MSC. RESULTS: MSC were successfully isolated from all 36 UC and six BM samples we collected for this study. The mean number of nucleated cells isolated from UC was 1yen106/cm and the yield of adherent cells was 8.6yen105/cm. UC-MSC shared most of the characteristic of BM-MSC, including fibroblastic-like morphology, immunophenotype, cell cycle status, adipogenic and osteogenic differentiation potentials, and hematopoiesis-supportive function. The CFU-F frequency was higher in UC nucleated cells (1:1609 +/- 0.18) than in BM nucleated cells (1:35700 +/- 0.01) (p < 0.05). Furthermore, in comparison with BM-MSC, the UC-MSC had a higher proliferation capacity and lower levels of expression of CD106 and HLA-ABC (p < 0.05). Immunofluoresent and western blot assays revealed that UC-MSC had a higher percentage of neuron specific enolase-positive cells than had BM-MSC after neuronal induction. Finally, reverse transcriptase polymerase chain reaction analysis showed that UC-MSC had a cytokine spectrum very similar to that of BM-MSC, including expression of the mRNA of stem cell factor, leukemia inhibitor factor, macrophage-colony stimulating factor, Flt3-ligand, interleukin-6, vascular endothelial growth factor and stromal-derived factor-1, but UC-MCS additionally expressed mRNA of granulocyte macrophage and granulocyte colony-stimulating factors. After co-culture with CD34+ cord blood cells for 5 weeks, no significant difference in colony-forming cells was observed between the CD34+ cells/UC-MSC and CD34+ cells/BM-MSC co-cultures (p > 0.05). INTERPRETATION AND CONCLUSIONS: We have established a protocol to isolate abundant MSC from human umbilical cords with a 100% success rate. The comparative study indicates that UC is an excellent alternative to BM as a source of MSC for cell therapies.

[Effect of silencing hypoxia-inducible factor-1 alpha by RNA interference on human breast carcinoma cell line].

OBJECTIVE: To investigate the effect of short hairpin RNA (shRNA) targeting hypoxia-inducible factor-1 alpha (HIF-1 alpha) on the human breast carcinoma MCF-7 cell line. METHODS: The hypoxia environment was achieved by treating cells with cobalt chloride. The shRNA eukaryotic expression vector targeting HIF-1 alpha was constructed, and transfected into MCF-7 cells through lipofectamine 2000. Semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) was used to study the expression of vascular endothelial growth factor (VEGF). The mRNA and protein level of HIF-1 alpha were detected by real-time PCR and Western blot. Sub-G1 apoptotic population analysis, Annexin V/PI binding assay, and DNA ladder analysis were applied to investigate the cell apoptosis. The cell cycle was detected by flow cytometry. RESULTS: The mRNA and protein level of HIF-1 alpha increased after exposure of MCF-7 cells to hypoxia (P < 0.01). However, apoptosis was lower in hypoxia compared with normoxia (P < 0.05). The HIF-1 level of MCF-7 transfected with HIF-1 alpha shRNA decreased approximately 91.63% (P < 0.01). When the cells were treated with or without apoptosis inducer Ara-C, the apoptosis of MCF-7 cells transfected with HIF-1 alpha shRNA increased by 1.75 times (P < 0.01) and 61. 31 times (P < 0.01), respectively. The expression of VEGF in MCF-7 cells transfected with HIF-1 alpha shRNA decreased 66.8% compared with untransfected cells (P < 0.05). Cell cycle progression was inhibited when the MCF-7 cells were transfected with HIF-1 alpha shRNA. CONCLUSIONS: HIF-1 alpha plays an anti-apoptotic role in human breast carcinoma MCF-7 cell line. The shRNA we designed targeting HIF-1 alpha in MCF-7 can promote cell apoptosis, inhibit the expression of VEGF, and delay cell cycle progression.

Heterogeneity of proangiogenic features in mesenchymal stem cells derived from bone marrow, adipose tissue, umbilical cord, and placenta.

BACKGROUND: Mesenchymal stem cells (MSCs) have been widely proven effective for therapeutic angiogenesis in ischemia animal models as well as clinical vascular diseases. Because of the invasive method, limited resources, and aging problems of adult tissue-derived MSCs, more perinatal tissue-derived MSCs have been isolated and studied as promising substitutable MSCs for cell transplantation. However, fewer studies have comparatively studied the angiogenic efficacy of MSCs derived from different tissues sources. Here, we evaluated whether the in-situ environment would affect the angiogenic potential of MSCs. METHODS: We harvested MSCs from adult bone marrow (BMSCs), adipose tissue (AMSCs), perinatal umbilical cord (UMSCs), and placental chorionic villi (PMSCs), and studied their "MSC identity" by flow cytometry and in-vitro trilineage differentiation assay. Then we comparatively studied their endothelial differentiation capabilities and paracrine actions side by side in vitro. RESULTS: Our data showed that UMSCs and PMSCs fitted well with the minimum standard of MSCs as well as BMSCs and AMSCs. Interestingly, we found that MSCs regardless of their tissue origins could develop similar endothelial-relevant functions in vitro, including producing eNOS and uptaking ac-LDL during endothelial differentiation in spite of their feeble expression of endothelial-related genes and proteins. Additionally, we surprisingly found that BMSCs and PMSCs could directly form tubular structures in vitro on Matrigel and their conditioned medium showed significant proangiogenic bioactivities on endothelial cells in vitro compared with those of AMSCs and UMSCs. Besides, several angiogenic genes were upregulated in BMSCs and PMSCs in comparison with AMSCs and UMSCs. Moreover, enzyme-linked immunosorbent assay further confirmed that BMSCs secreted much more VEGF, and PMSCs secreted much more HGF and PGE2. CONCLUSIONS: Our study demonstrated the heterogeneous proangiogenic properties of MSCs derived from different tissue origins, and the in vivo isolated environment might contribute to these differences. Our study suggested that MSCs derived from bone marrow and placental chorionic villi might be preferred in clinical application for therapeutic angiogenesis.

VCAM-1+ placenta chorionic villi-derived mesenchymal stem cells display potent pro-angiogenic activity.

INTRODUCTION: Mesenchymal stem cells (MSCs) represent a heterogeneous cell population that is promising for regenerative medicine. The present study was designed to assess whether VCAM-1 can be used as a marker of MSC subpopulation with superior angiogenic potential. METHODS: MSCs were isolated from placenta chorionic villi (CV). The VCAM-1(+/-) CV-MSCs population were separated by Flow Cytometry and subjected to a comparative analysis for their angiogenic properties including angiogenic genes expression, vasculo-angiogenic abilities on Matrigel in vitro and in vivo, angiogenic paracrine activities, cytokine array, and therapeutic angiogenesis in vascular ischemic diseases. RESULTS: Angiogenic genes, including HGF, ANG, IL8, IL6, VEGF-A, TGFß, MMP2 and bFGF, were up-regulated in VCAM-1(+)CV-MSCs. Consistently, angiogenic cytokines especially HGF, IL8, angiogenin, angiopoitin-2, µPAR, CXCL1, IL-1ß, IL-1α, CSF2, CSF3, MCP-3, CTACK, and OPG were found to be significantly increased in VCAM-1(+) CV-MSCs. Moreover, VCAM-1(+)CV-MSCs showed remarkable vasculo-angiogenic abilities by angiogenesis analysis with Matrigel in vitro and in vivo and the conditioned medium of VCAM-1(+) CV-MSCs exerted markedly pro-proliferative and pro-migratory effects on endothelial cells compared to VCAM-1(-)CV-MSCs. Finally, transplantation of VCAM-1(+)CV-MSCs into the ischemic hind limb of BALB/c nude mice resulted in a significantly functional improvement in comparison with VCAM-1(-)CV-MSCs transplantation. CONCLUSIONS: VCAM-1(+)CV-MSCs possessed a favorable angiogenic paracrine activity and displayed therapeutic efficacy on hindlimb ischemia. Our results suggested that VCAM-1(+)CV-MSCs may represent an important subpopulation of MSC for efficient therapeutic angiogenesis.