Pluripotent marker expression and differentiation of human second trimester Mesenchymal Stem Cells

Comparison of SOX2 and POU5F1 Gene Expression in Leukapheresis-Derived CD34+ Cells before and during Cell Culture

Bone marrow is an abundant source of both hematopoietic as well as non-hematopoietic stem cells. Embryonic, fetal and stem cells located in tissues (adipose tissue, skin, myocardium and dental pulp) express core transcription factors, including the SOX2, POU5F1 and NANOG gene responsible for regeneration, proliferation and differentiation into daughter cells. The aim of the study was to examine the expression of SOX2 and POU5F1 genes in CD34-positive peripheral blood stem cells (CD34+ PBSCs) and to analyze the influence of cell culture on the expression of SOX2 and POU5F1 genes. The study material consisted of bone marrow-derived stem cells isolated by using leukapheresis from 40 hematooncology patients. Cells obtained in this process were subject to cytometric analysis to determine the content of CD34+ cells. CD34-positive cell separation was conducted using MACS separation. Cell cultures were set, and RNA was isolated. Real-time PCR was conducted in order to evaluate the expression of SOX2 and POU5F1 genes and the obtained data were subject to statistical analysis. We identified the expression of SOX2 and POU5F1 genes in the examined cells and demonstrated a statistically significant (p < 0.05) change in their expression in cell cultures. Short-term cell cultures (<6 days) were associated with an increase in the expression of SOX2 and POU5F1 genes. Thus, short-term cultivation of transplanted stem cells could be used to induce pluripotency, leading to better therapeutic effects.

Implication of Cellular Senescence in Osteoarthritis: A Study on Equine Synovial Fluid Mesenchymal Stromal Cells

Osteoarthritis (OA) is described as a chronic degenerative disease characterized by the loss of articular cartilage. Senescence is a natural cellular response to stressors. Beneficial in certain conditions, the accumulation of senescent cells has been implicated in the pathophysiology of many diseases associated with aging. Recently, it has been demonstrated that mesenchymal stem/stromal cells isolated from OA patients contain many senescent cells that inhibit cartilage regeneration. However, the link between cellular senescence in MSCs and OA progression is still debated. In this study, we aim to characterize and compare synovial fluid MSCs (sf-MSCs), isolated from OA joints, with healthy sf-MSCs, investigating the senescence hallmarks and how this state could affect cartilage repair. Sf-MSCs were isolated from tibiotarsal joints of healthy and diseased horses with an established diagnosis of OA with an age ranging from 8 to 14 years. Cells were cultured in vitro and characterized for cell proliferation assay, cell cycle analysis, ROS detection assay, ultrastructure analysis, and the expression of senescent markers. To evaluate the influence of senescence on chondrogenic differentiation, OA sf-MSCs were stimulated in vitro for up to 21 days with chondrogenic factors, and the expression of chondrogenic markers was compared with healthy sf-MSCs. Our findings demonstrated the presence of senescent sf-MSCs in OA joints with impaired chondrogenic differentiation abilities, which could have a potential influence on OA progression.

Evaluation of the Impact of Pregnancy-Associated Factors on the Quality of Wharton's Jelly-Derived Stem Cells Using SOX2 Gene Expression as a Marker

SOX2 is a recognized pluripotent transcription factor involved in stem cell homeostasis, self-renewal and reprogramming. It belongs to, one of the SRY-related HMG-box (SOX) family of transcription factors, taking part in the regulation of embryonic development and determination of cell fate. Among other functions, SOX2 promotes proliferation, survival, invasion, metastasis, cancer stemness, and drug resistance. SOX2 interacts with other transcription factors in multiple signaling pathways to control growth and survival. The aim of the study was to determine the effect of a parturient’s age, umbilical cord blood pH and length of pregnancy on the quality of stem cells derived from Wharton’s jelly (WJSC) by looking at birth weight and using SOX2 gene expression as a marker. Using qPCR the authors, evaluated the expression of SOX2 in WJSC acquired from the umbilical cords of 30 women right after the delivery. The results showed a significant correlation between the birth weight and the expression of SOX2 in WJSC in relation to maternal age, umbilical cord blood pH, and the length of pregnancy. The authors observed that the younger the woman and the lower the umbilical cord blood pH, the earlier the delivery occurs, the lower the birth weight and the higher SOX2 gene expression in WJSC. In research studies and clinical applications of regenerative medicine utilizing mesenchymal stem cells derived from Wharton’s Jelly of the umbilical cord, assessment of maternal and embryonic factors influencing the quality of cells is critical.

Effect of gestational age on migration ability of the human umbilical cord vein mesenchymal stem cells

PURPOSE

Migration ability of mesenchymal stem cells (MSCs) towards chemotactic mediators is a determinant factor in cell therapy. MSCs derived from different sources show different properties. Here we compared the migration ability of the term and the pre-term human umbilical cord vein MSCs (hUCV-MSCs).

MATERIALS/METHODS

MSCs were isolated from term and pre-term umbilical cord vein, and cultured to passage 3-4. Migration rate of both groups was assessed in the presence of 10% FBS using chemotaxis assay. Surface expression of CXCR4 was measured by flow cytometery. The relative gene expression of CXCR4, IGF1-R, PDGFRα, MMP-2, MMP-9, MT1-MMP and TIMP-2 were evaluated using real time PCR.

RESULTS

The isolation rate of the pre-term hUCV-MSCs was higher than the term hUCV-MSCs. Phenotype characteristics and differentiation ability of the term and pre-term hUCV-MSCs were not different. The migration rate of the pre-term hUCV-MSCs was more than the term hUCV-MSCs. Gene and surface expressions of the CXCR4 were both significantly higher in the pre-term hUCV-MSCs (P≤0.05). The mRNA levels of PDGFRα, MMP-2, MMP-9, MT1-MMP and TIMP-2 showed no significant difference between the two groups.

CONCLUSION

Our results showed that the gestational age can affect the migration ability of the hUCV-MSCs.

Equine metabolic syndrome impairs adipose stem cells osteogenic differentiation by predominance of autophagy over selective mitophagy

Adipose‐derived mesenchymal stem cells (ASC) hold great promise in the treatment of many disorders including musculoskeletal system, cardiovascular and/or endocrine diseases. However, the cytophysiological condition of cells, used for engraftment seems to be fundamental factor that might determine the effectiveness of clinical therapy. In this study we investigated growth kinetics, senescence, accumulation of oxidative stress factors, mitochondrial biogenesis, autophagy and osteogenic differentiation potential of ASC isolated from horses suffered from equine metabolic syndrome (EMS). We demonstrated that EMS condition impairs multipotency/pluripotency in ASCs causes accumulation of reactive oxygen species and mitochondria deterioration. We found that, cytochrome c is released from mitochondria to the cytoplasm suggesting activation of intrinsic apoptotic pathway in those cells. Moreover, we observed up‐regulation of p21 and decreased ratio of Bcl‐2/BAX. Deteriorations in mitochondria structure caused alternations in osteogenic differentiation of ASC_EMS resulting in their decreased proliferation rate and reduced expression of osteogenic markers BMP‐2 and collagen type I. During osteogenic differentiation of ASC_EMS, we observed autophagic turnover as probably, an alternative way to generate adenosine triphosphate and amino acids required to increased protein synthesis during differentiation. Downregulation of PGC1α, PARKIN and PDK4 in differentiated ASC_EMS confirmed impairments in mitochondrial biogenesis and function. Hence, application of ASC_EMS into endocrinological or ortophedical practice requires further investigation and analysis in the context of safeness of their application.

Chorionic villi derived mesenchymal like stem cells and expression of embryonic stem cells markers during long-term culturing

Mesenchymal stem cells (MSCs) can be obtained from a variety of human tissues. MSCs derived from placental chorionic villi of the first trimester are likely to resemble, biologically, embryonic stem cells (ESC), due to the earlier development stage of placenta. In the present study long-term cultures of MSC-like cells were assessed in order to evaluate MSCs multipotent characteristics and molecular features during the period of culture. CV-cells obtained from 10 samples of chorionic villus displayed typical fibroblastoid morphology, undergone 20 passages during a period of 120 days, maintaining a stable karyotype throughout long term expansion. The cells were positive, for CD90, CD73, CD105, CD29, CD44, HLA ABC antigens and negative for CD14, CD34, AC133, and HLA DR antigens as resulted from the flow cytometry analysis. CV-cells were differentiated in adipocytes, osteoblasts, chondrocytes and neuronal cells under specific culture conditions. The expression of the ESC-gene markers POU5F1 (Oct-4) and NANOG was observed at earliest stages (4-12 passages) and not at the late stages (14-20 passages) by RT-PCR analysis. ZFP42 and SOX2 expression were not detected. Moreover, CV-cells were found to express GATA4 but not NES (Nestin). Chorionic villi-derived cells possess multipotent properties, display high proliferation rate and self-renew capacity, share common surface antigens with adult MSCs and express certain embryonics stem cells gene markers. These characteristics highlight chorionic villi as an attractive source of MSCs for the needs of regenerative medicine.

Osteogenic differentiation of human mesenchymal stem cells in the absence of osteogenic supplements: A surface-roughness gradient study

The use of biomaterials to direct osteogenic differentiation of human mesenchymal stem cells (hMSCs) in the absence of osteogenic supplements is thought to be part of the next generation of orthopedic implants. We previously engineered surface-roughness gradients of average roughness (Ra) varying from the sub-micron to the micrometer range (∼0.5-4.7 μm), and mean distance between peaks (RSm) gradually varying from ∼214 μm to 33 μm. Here we have screened the ability of such surface-gradients of polycaprolactone to influence the expression of alkaline phosphatase (ALP), collagen type 1 (COL1) and mineralization by hMSCs cultured in dexamethasone (Dex)-deprived osteogenic induction medium (OIM) and in basal growth medium (BGM). Ra∼1.53 μm/RSm∼79 μm in Dex-deprived OI medium, and Ra∼0.93 μm/RSm∼135 μm in BGM consistently showed higher effectiveness at supporting the expression of the osteogenic markers ALP, COL1 and mineralization, compared to the tissue culture polystyrene (TCP) control in complete OIM. The superior effectiveness of specific surface-roughness revealed that this strategy may be used as a compelling alternative to soluble osteogenic inducers in orthopedic applications featuring the clinically relevant biodegradable polymer polycaprolactone.

STATEMENT OF SIGNIFICANCE

Biodegradable polymers, such as polycaprolactone (PCL), are promising materials in the field of tissue engineering and regenerative medicine, which aims at creating viable options to replace permanent orthopedic implants. The material, cells, and growth-stimulating factors are often referred to as the key components of engineered tissues. In this article, we studied the hypothesis of specific surface modification of PCL being capable of inducing mesenchymal stem cell differentiation in bone cells in the absence of cell-differentiating factors. The systematic investigation of the linearly varying surface-roughness gradient showed that an average PCL roughness of 0.93 μm alone can serve as a compelling alternative to soluble osteogenic inducers in orthopedic applications featuring the clinically relevant biodegradable polymer polycaprolactone.

Age Does Matter: A Pilot Comparison of Placenta-Derived Stromal Cells for in utero Repair of Myelomeningocele Using a Lamb Model

INTRODUCTION

Fetal amniotic membranes (FM) have been shown to preserve spinal cord histology in the fetal sheep model of myelomeningocele (MMC). This study compares the effectiveness of placenta-derived mesenchymal stromal cells (PMSCs) from early-gestation versus term-gestation placenta to augment FM repair to improve distal motor function in a sheep model.

METHODS

Fetal lambs (n = 4) underwent surgical MMC creation followed by repair with FM patch with term-gestation PMSCs (n = 1), FM with early-gestation PMSCs (n = 1), FM only (n = 1), and skin closure only (n = 1). Histopathology and motor assessment was performed.

RESULTS

Histopathologic analysis demonstrated increased preservation of spinal cord architecture and large neurons in the lamb repaired with early-gestation cells compared to all others. Lambs repaired with skin closure only, FM alone, and term-gestation PMSCs exhibited extremely limited distal motor function; the lamb repaired with early-gestation PMSCs was capable of normal ambulation.

DISCUSSION

This pilot study is the first in vivo comparison of different gestational-age placenta-derived stromal cells for repair in the fetal sheep MMC model. The preservation of large neurons and markedly improved motor function in the lamb repaired with early-gestation cells suggest that early-gestation placental stromal cells may exhibit unique properties that augment in utero MMC repair to improve paralysis.

Unravelling the pluripotency paradox in fetal and placental mesenchymal stem cells: Oct-4 expression and the case of The Emperor's New Clothes

Mesenchymal stem cells (MSC) from fetal-placental tissues have translational advantages over their adult counterparts, and have variably been reported to express pluripotency markers. OCT-4 expression in fetal-placental MSC has been documented in some studies, paradoxically without tumourogenicity in vivo. It is possible that OCT-4 expression is insufficient to induce true "stemness", but this issue is important for the translational safety of fetal-derived MSC. To clarify this, we undertook a systematic literature review on OCT-4 in fetal or adnexal MSC to show that most studies report OCT-4 message or protein expression, but no study provides definitive evidence of true OCT-4A expression. Discrepant findings were attributable not to different culture conditions, tissue sources, or gestational ages but instead to techniques used. In assessing OCT-4 as a pluripotency marker, we highlight the challenges in detecting the correct OCT-4 isoform (OCT-4A) associated with pluripotency. Although specific detection of OCT-4A mRNA is achievable, it appears unlikely that any antibody can reliably distinguish between OCT-4A and the pseudogene OCT-4B. Finally, using five robust techniques we demonstrate that fetal derived-MSC do not express OCT-4A (or by default OCT-4B). Reports suggesting OCT-4 expression in fetal-derived MSC warrant reassessment, paying attention to gene and protein isoforms, pseudogenes, and antibody choice as well as primer design. Critical examination of the OCT-4 literature leads us to suggest that OCT-4 expression in fetal MSC may be a case of "The Emperor's New Clothes" with early reports of (false) positive expression amplified in subsequent studies without critical attention to emerging refinements in knowledge and methodology.

Marker gene screening for human mesenchymal stem cells in early osteogenic response to bone morphogenetic protein 6 with DNA microarray

AIMS

Microarray data were analyzed using bioinformatic tools to screen marker genes of human mesenchymal stem cells (hMSC) in response to bone morphogenetic protein 6 (BMP6).

RESULTS

A total of 190 differentially expressed genes were identified. The interaction network was divided into three functional modules. These genes were connected with BMP signaling pathways and regulation of cell processes, while NOG and BMPR2 participated in the transforming growth factor-beta signal pathway. Besides, several related small molecules were acquired.

CONCLUSION

Marker genes in osteogenic responses to BMP6 treatment for hMSC were screened with microarray data along with elaborate function analysis by bioinformatics. NOG and BMPR2 showed potential to become indicators to monitor the directed differentiation of hMSC into osteoblasts, which can be used for bone disease treatment. Moreover, small molecules such as W-13 were retrieved and provided directions for future drug design.

Isolation and characterization of multipotent cells from human fetal dermis

We report that cells from human fetal dermis, termed here multipotent fetal dermal cells, can be isolated with high efficiency by using a nonenzymatic, cell outgrowth method. The resulting cell population was consistent with the definition of mesenchymal stromal cells by the International Society for Cellular Therapy. As multipotent fetal dermal cells proliferate extensively, with no loss of multilineage differentiation potential up to passage 25, they may be an ideal source for cell therapy to repair damaged tissues and organs. Multipotent fetal dermal cells were not recognized as targets by T lymphocytes in vitro, thus supporting their feasibility for allogenic transplantation. Moreover, the expansion protocol did not affect the normal phenotype and karyotype of cells. When compared with adult dermal cells, fetal cells displayed several advantages, including a greater cellular yield after isolation, the ability to proliferate longer, and the retention of differentiation potential. Interestingly, multipotent fetal dermal cells expressed the pluripotency marker SSEA4 (90.56 ± 3.15% fetal vs. 10.5 ± 8.5% adult) and coexpressed mesenchymal and epithelial markers (>80% CD90(+)/CK18(+) cells), coexpression lacking in the adult counterparts isolated under the same conditions. Multipotent fetal dermal cells were able to form capillary structures, as well as differentiate into a simple epithelium in vitro, indicating skin regeneration capabilities.

Age-associated changes in the ecological niche: implications for mesenchymal stem cell aging

Adult stem cells are critical for organ-specific regeneration and self-renewal with advancing age. The prospect of being able to reverse tissue-specific post-injury sequelae by harvesting, culturing and transplanting a patient's own stem and progenitor cells is exciting. Mesenchymal stem cells have emerged as a reliable stem cell source for this treatment modality and are currently being tested in numerous ongoing clinical trials. Unfortunately, the fervor over mesenchymal stem cells is mitigated by several lines of evidence suggesting that their efficacy is limited by natural aging. This article discusses the mechanisms and manifestations of age-associated deficiencies in mesenchymal stem cell efficacy. A consideration of recent experimental findings suggests that the ecological niche might be responsible for mesenchymal stem cell aging.

Dental pulp stem cells differentiation reveals new insights in Oct4A dynamics

Although the role played by the core transcription factor network, which includes c-Myc, Klf4, Nanog, and Oct4, in the maintenance of embryonic stem cell (ES) pluripotency and in the reprogramming of adult cells is well established, its persistence and function in adult stem cells are still debated. To verify its persistence and clarify the role played by these molecules in adult stem cell function, we investigated the expression pattern of embryonic and adult stem cell markers in undifferentiated and fully differentiated dental pulp stem cells (DPSC). A particular attention was devoted to the expression pattern and intracellular localization of the stemness-associated isoform A of Oct4 (Oct4A). Our data demonstrate that: Oct4, Nanog, Klf4 and c-Myc are expressed in adult stem cells and, with the exception of c-Myc, they are significantly down-regulated following differentiation. Cell differentiation was also associated with a significant reduction in the fraction of DPSC expressing the stem cell markers CD10, CD29 and CD117. Moreover, a nuclear to cytoplasm shuttling of Oct4A was identified in differentiated cells, which was associated with Oct4A phosphorylation. The present study would highlight the importance of the post-translational modifications in DPSC stemness maintenance, by which stem cells balance self-renewal versus differentiation. Understanding and controlling these mechanisms may be of great importance for stemness maintenance and stem cells clinical use, as well as for cancer research.

Age-related changes in rat bone-marrow mesenchymal stem cell plasticity

Background

The efficacy of adult stem cells is known to be compromised as a function of age. This therefore raises questions about the effectiveness of autologous cell therapy in elderly patients.

Results

We demonstrated that the expression profile of stemness markers was altered in BM-MSCs derived from old rats. BM-MSCs from young rats (4 months) expressed Oct-4, Sox-2 and NANOG, but we failed to detect Sox-2 and NANOG in BM-MSCs from older animals (15 months). Chondrogenic, osteogenic and adipogenic potential is compromised in old BM-MSCs. Stimulation with a cocktail mixture of bone morphogenetic protein (BMP-2), fibroblast growth factor (FGF-2) and insulin-like growth factor (IGF-1) induced cardiomyogenesis in young BM-MSCs but not old BM-MSCs. Significant differences in the expression of gap junction protein connexin-43 were observed between young and old BM-MSCs. Young and old BM-MSCs fused with neonatal ventricular cardiomyocytes in co-culture and expressed key cardiac transcription factors and structural proteins. Cells from old animals expressed significantly lower levels of VEGF, IGF, EGF, and G-CSF. Significantly higher levels of DNA double strand break marker γ-H2AX and diminished levels of telomerase activity were observed in old BM-MSCs.

Conclusion

The results suggest age related differences in the differentiation capacity of BM-MSCs. These changes may affect the efficacy of BM-MSCs for use in stem cell therapy.

Mesenchymal stem cells from bone marrow show a stronger stimulating effect on megakaryocyte progenitor expansion than those from non-hematopoietic tissues

In order to evaluate whether mesenchymal stem cells (MSCs) from non-hematopoietic tissues are able to regulate megakaryocytopoiesis, we identified human MSCs from adult bone marrow (ABM), fetal pancreas (FPan) and umbilical cord (UC), and their abilities to support megakaryocyte (MK) differentiation from CD34(+) hematopoietic progenitor cells (HPCs) were comparatively studied. First, MSCs were isolated from ABM, FPan and UC then their growth kinetics, molecular characterization and mesodermal differentiation capacity were determined. ABM-MSCs, FPan-MSCs and UC-MSCs were irradiated and cocultured with human umbilical cord blood (UCB) CD34(+) cells, and the expansion efficiency of MK progenitor cells and MK formation were analysed and compared. Finally, SCF, IL-6 and GM-CSF expression by the three types of MSCs were also examined. Our results showed that FPan-MSCs and UC-MSCs shared most of the characteristic of ABM-MSCs, including morphology, immunophenotype, adipogenic and osteogenic differentiation potentials. Compared with ABM-MSCs, fetal MSCs had higher proliferative capacity. After 7 days' coculture, the maximal production of CD34(+)/CD41a(+) cells was obtained in a group of CD34(+) HPCs + ABM-MSCs. Furthermore, this group produced more MK colonies than other groups (p < 0.05). Surface antigen and ploidy analysis morphological observation demonstrated that a proportion of expanded cells in each group differentiated into mature MKs. ABM-MSCs, FPan-MSCs and UC-MSCs were revealed to express SCF, IL-6 and GM-CSF at mRNA level. We conclude that FPan-MSCs and UC-MSCs have the ability to promote megakaryocytopoiesis, while ABM-MSCs expand more MK progenitor cells from CD34(+) HPCs than MSCs from non-hematopoietic tissues and CD34(+) cells alone.

Simulated microgravity maintains the undifferentiated state and enhances the neural repair potential of bone marrow stromal cells

Recently, regenerative medicine with bone marrow stromal cells (BMSCs) has gained significant attention for the treatment of central nervous system diseases. Here, we investigated the activity of BMSCs under simulated microgravity conditions. Mouse BMSCs (mBMSCs) were isolated from C57BL/6 mice and harvested in 1G condition. Subjects were divided into 4 groups: cultured under simulated microgravity and 1G condition in growth medium and neural differentiation medium. After 7 days of culture, the mBMSCs were used for morphological analysis, reverse transcription (RT)-polymerase chain reaction, immunostaining analysis, and grafting. Neural-induced mBMSCs cultured under 1G conditions exhibited neural differentiation, whereas those cultured under simulated microgravity did not. Moreover, under simulated microgravity conditions, mBMSCs could be cultured in an undifferentiated state. Next, we intravenously injected cells into a mouse model of cerebral contusion. Graft mBMSCs cultured under simulated microgravity exhibited greater survival in the damaged region, and the motor function of the grafted mice improved significantly. mBMSCs cultured under simulated microgravity expressed CXCR4 on their cell membrane. Our study indicates that culturing cells under simulated microgravity enhances their survival rate by maintaining an undifferentiated state of cells, making this a potentially attractive method for culturing donor cells to be used in grafting.

Human cardiac explant-conditioned medium: soluble factors and cardiomyogenic effect on mesenchymal stem cells

The use of conditioned medium (CM) from human cardiac explants (HCEs) as a potential source of paracrine factors for adult stem cell signaling has never been evaluated. We hypothesized that HCEs might provide a source of soluble factors triggering the differentiation of mesenchymal stem cells (MSCs) into cardiomyocyte-like cells. By using two-dimensional electrophoresis (2-DE) gels/mass spectrometry and antibody macroarray assays, we found that HCEs release macromolecules, including cytokines, growth factors and myocardial and metabolism-related proteins into the culture medium. We identified a total of 20 proteins in the HCE-CM. However, as shown by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and 2-DE, these 20 proteins account for only a fraction of the total number of proteins present in the HCE-CM. We also found that CM increased the proliferation of bone marrow-derived-MSCs (BM-MSCs) in vitro. Unlike the other effects, this effect was most evident after 48 h of culture. Moreover, we examined the effect of HCE-CM on levels of mRNA and protein for specific cardiac markers. We showed that a surprisingly big fraction of BM-MSCs (3.4-5.0%) treated in vitro with HCE-CM became elongated and began to express cardiac markers, consistent with their possible differentiation into cardiomyocyte-like cells. Our in vitro model may be useful not only per se, but also for studies of the mechanisms of action of soluble factors involved in cell differentiation, paving the way for possible new protein-based treatments in the future.

Transcriptional regulation of oct4 in human bone marrow mesenchymal stem cells

Oct4 is a key transcription factor to maintain self-renewal and undifferentiated state of embryonic stem cells. Site 2A located between -2,546 and -2,530 bp and site 2B between -2,500 and -2,486 bp of human Oct4 gene were shown to be sufficient for inducing Oct4 gene expression in embryonic stem cells. Site 2B contains octamer element capable of binding to factor Oct4 and sox element capable of binding to factor Sox2. So far, little is known about the molecular mechanisms for the control of growth and differentiation of adult stem cells including bone marrow-derived mesenchymal stem cells (BM-MSCs), and it is important to understand how Oct4 expression is regulated in BM-MSCs. This study showed that Oct4 and Sox2 genes were expressed in undifferentiated BM-MSCs and BM-MSCs on day 7 but not on days 14 and 21 following osteogenic induction. Site 2A of Oct4 gene, not site 2B, activated the expression of reporter genes luciferase and enhanced green fluorescent protein in undifferentiated BM-MSCs but not in BM-MSCs following osteogenic differentiation. These data demonstrate that site 2A is sufficient for inducing the expression of Oct4 gene in BM-MSCs, and site 2B is not required. Electrophoretic mobility shift assay showed the 2 shifted bands with site 2B probe and the addition of Oct4 and Sox2 antibodies did not supershift these 2 bands. As probes containing mutated octamer and sox elements of site 2B still gave the same 2 shifted bands, it was concluded that they did not result from the binding to site 2B probe by factors Oct4 and Sox2. These bands may be due to the binding of 2 unknown transcription factors.

Characterization and expansion of mesenchymal progenitor cells from first-trimester chorionic villi of human placenta

BACKGROUND

Mesenchymal stromal cells (MSC) have been identified in a variety of fetal and adult tissues, including bone marrow (BM), fetal blood and liver. We report on the isolation, expansion and differentiation in vitro of MSC-like cells from chorionic villi (CV).

METHODS

We evaluated 10 samples of CV collected at the first trimester (gestational age 11-13 weeks). We only used cells taken from back-up culture after a successful karyotype analysis. CV cells were characterized by morphologic, immunophenotypic and molecular analysis. The differentiation ability of mesenchymal and neural lineages was detected using specific culture conditions. Cell expansion was assessed after plating cells at different densities in different media, supplemented with animal and human serum.

RESULTS

CV cells showed a homogeneous population of spindle-shaped cells after the first passage. Cells expressed CD90, CD105, CD73, CD44, CD29 and CD13 but not CD45, CD14, CD34 and CD117. They expressed Oct-4, Rex-1, GATA-4 and nestin, which characterize the undifferentiated stem cell state. They differentiated into osteocytes, adipocytes, chondrocytes and neuronal cells. Cell expansion was greater than that of adult BM-derived MSC, 9 logs with fetal bovine serum and 6 logs with human serum. Despite their high proliferative capacity, we did not observe any karyotypic abnormalities after culture.

DISCUSSION

Our study shows that CV cells have better potential for expansion than adult stem cells. They can proliferate in a medium with human allogeneic serum and can differentiate into mesenchymal and neural lineages. CV cells may be an excellent cell source for therapeutic applications.

Comparison of cytokine expression in mesenchymal stem cells from human placenta, cord blood, and bone marrow

Mesenchymal stem cells (MSCs) are capable of self-renewal and differentiation into lineages of mesenchymal tissues that are currently under investigation for a variety of therapeutic applications. The purpose of this study was to compare cytokine gene expression in MSCs from human placenta, cord blood (CB) and bone marrow (BM). The cytokine expression profiles of MSCs from BM, CB and placenta (amnion, decidua) were compared by proteome profiler array analysis. The cytokines that were expressed differently, in each type of MSC, were analyzed by real-time PCR. We evaluated 36 cytokines. Most types of MSCs had a common expression pattern including MIF (GIF, DER6), IL-8 (CXCL8), Serpin E1 (PAI-1), GROalpha(CXCL1), and IL-6. MCP-1, however, was expressed in both the MSCs from the BM and the amnion. sICAM-1 was expressed in both the amnion and decidua MSCs. SDF-1 was expressed only in the BM MSCs. Real-time PCR demonstrated the expression of the cytokines in each of the MSCs. The MSCs from bone marrow, placenta (amnion and decidua) and cord blood expressed the cytokines differently. These results suggest that cytokine induction and signal transduction are different in MSCs from different tissues.

Human multipotent mesenchymal stromal cells from fetal lung expressing pluripotent markers and differentiating into cell types of three germ layers

Multipotent mesenchymal stromal cells (MSCs) are a promising cell type for cell transplantation; however, their utilization remains limited until the availability of adequate alternative sources of MSCs and the thorough understanding of the biology of MSCs isolated from various sources are realized. Fetal lung has been identified as a rich source of MSCs. To explore the therapeutic potential of passaged fetal lung MSCs (FLMSCs), the present study evaluated their growth kinetics, telomere length, karyotype, immunophenotype, and the differentiation potential during in vitro expansion. FLMSCs could be easily amplified in vitro with no significant shorting of telomere length and had a normal karyotype. No significant differences between passage 5 or passage 25 were observed in the immunophenotype analysis using flow cytometry. Moreover, flow cytometry results provided the first demonstration, to our knowledge, that FLMSCs stably expressed pluripotent markers including Oct4, Nanog, Sox2, TRA-1-60, c-Myc, and SSEA-4 through 25 passages. In vitro differentiation studies as identified by confocal microscopy, flow cytometry, RT-PCR, and immunohistochemistry showed that FLMSCs had extended capacity of differentiating into mesodermal, ectodermal, and endodermal lineages, and that their potential for adipogenic, osteogenic, and chondrogenic differentiation may be maintained over 25 passages. Furthermore, osteogenic and chondrogenic differentiation was used as an indicator of their differentiation capability in vivo, as evidenced by ectopic bone and cartilage formation. In summary, these results suggest that FLMSCs are a primitive population and that their extensive in vitro expansion does not involve significant functional modification of the cells, including morphology, growth, karyotype, immunophenotype, and mesodermal differentiation potential. Hence, FLMSCs might constitute an attractive cell resource for cell transplantation to induce regeneration of damaged tissues/organs.

Expression of cardiac function genes in adult stem cells is increased by treatment with nitric oxide agents

Mesenchymal stem cells (MSCs) have received special attention for cardiomyoplasty because several studies have shown that they differentiate into cardiomyocytes both in vitro and in vivo. Nitric oxide (NO) is a free radical signaling molecule that regulates several differentiation processes including cardiomyogenesis. Here, we report an investigation of the effects of two NO agents (SNAP and DEA/NO), able to activate both cGMP-dependent and -independent pathways, on the cardiomyogenic potential of bone marrow-derived mesenchymal stem cells (BM-MSCs) and adipose tissue-derived stem cells (ADSCs). The cells were isolated, cultured and treated with NO agents. Cardiac- and muscle-specific gene expression was analyzed by indirect immunofluorescence, flow cytometry, RT-PCR and real-time PCR. We found that untreated (control) ADSCs and BM-MSCs expressed some muscle markers and NO-derived intermediates induce an increased expression of some cardiac function genes in BM-MSCs and ADSCs. Moreover, NO agents considerably increased the pro-angiogenic potential mostly of BM-MSCs as determined by VEGF mRNA levels.

Glandular stem cells are a promising source for much more than beta-cell replacement

Glandular stem cells (GSCs) can be obtained from exocrine glands such as pancreas or salivary glands using well-established cell culturing methods. The resulting cell populations are characterized by a high proliferative capacity and an unusually high plasticity. Cells from pancreas have been demonstrated to differentiate into a multitude of cell types and even into oocyte-like cells. It has been found that the preparation method for GSCs can be applied to many vertebrates, including fishes and birds. Since the cells are excellently cryopreservable, this finding has been utilized to establish a new stem cell bank for preserving living cells of rare and wild animals. Apart from these advances, this mini-review also points out that GSCs from pancreas must not be confused with beta-cell progenitors but constitute a distinct cell type.