Human bone marrow stromal cell: coexpression of markers specific for multiple mesenchymal cell lineages

TMT-based quantitative proteomic analysis revealed that FBLN2 and NPR3 are involved in the early osteogenic differentiation of mesenchymal stem cells (MSCs)

The delicate equilibrium between osteoblast and adipocyte differentiation of MSCs is highly regulated. We screened for early-stage osteogenesis- or adipogenesis-based MSCs protein expression profiles using TMT-based quantitative proteomic analysis to identify novel participating molecules. Protein annotation, hierarchical clustering, functional stratification, and protein-protein association assessments were performed. Moreover, two upregulated proteins, namely, FBLN2 and NPR3, were validated to participate in the osteogenic differentiation process of MSCs. After that, we independently downregulated FBLN2 and NPR3 over seven days of osteogenic differentiation, and we performed quantitative proteomics analysis to determine how different proteins were regulated in knockdown vs. control cells. Based on gene ontology (GO) and network analyses, FBLN2 deficiency induced functional alterations associated with biological regulation and stimulus-response, whereas NPR3 deficiency induced functional alterations related to cellular and metabolic processes, and so on. These findings suggested that proteomics remains a useful method for an in-depth study of the MSCs differentiation process. This will assist in comprehensively evaluating its role in osteoporosis and provide additional approaches for identifying as-yet-unidentified effector molecules.

In vivo bone regeneration using a bioactive nanocomposite scaffold and human mesenchymal stem cells

Due to the osteoconductive role of bioceramics, use of these bioactive nanocomposite scaffolds that can maintain their structural integrity during bone tissue repair is one of the major goals of tissue engineering. Herein, a nanofibrous poly-L-lactic acid (PLLA) scaffold was fabricated by electrospinning and then gelatin and hydroxyapatite nanoparticles (nHA) were coated over the surface of the scaffold. Osteoconductivity of the fabricated nano-composite scaffolds was then studied while grafted on the rat calvarial defects. Our results indicated that the coating of PLLA scaffold with nHA and gelatin increased the adhesion and growth of the human bone marrow derived mesenchymal stem cells (BM-MSCs) and also significantly increased the level of mineralization over a week culture period. The results of radiographic and histological studies showed that the newly created bone tissue at the defect site was significantly higher in animals treated with nanocomposite scaffolds than the empty scaffolds and control groups. This increase in the defect reconstruction was significantly increased after culturing BM-MSCs on the scaffolds, especially nanocomposite scaffolds. It can be concluded that the combination of nanocomposite scaffolds and BM-MSCs could be a very good candidate for treatment of bone lesions and could be considered as a bony bioimplant.

Coronavirus Disease of 2019: a Mimicker of Dengue Infection?

At the beginning of 2020, the national health system and medical communities are faced with unprecedented public health challenges. A novel strain of coronavirus, later identified as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has spread globally, marking another pandemic of coronaviruses. This viral disease is responsible for devastating pneumonia, named coronavirus disease of 2019 (COVID-19), and projected to persist until the end of the year. In tropical countries, however, concerns arise regarding the similarities of COVID-19 with other infectious diseases due to the same chief complaint, which is fever. One of the infectious disease of a primary concern is dengue infection, which its peak season is approaching. Others report that there are cases of serological cross-reaction of COVID-19 and dengue infection. In this comprehensive review, we underscore the importance of knowing similar clinical presentations of both diseases and emphasize why excluding COVID-19 in the differentials in the setting of a pandemic is imprudent.

Development of a novel in vitro insulin resistance model in primary human tenocytes for diabetic tendinopathy research

Background

Type 2 diabetes mellitus (T2DM) had been reported to be associated with tendinopathy. However, the underlying mechanisms of diabetic tendinopathy still remain largely to be discovered. The purpose of this study was to develop insulin resistance (IR) model on primary human tenocytes (hTeno) culture with tumour necrosis factor-alpha (TNF-α) treatment to study tenocytes homeostasis as an implication for diabetic tendinopathy.

Methods

hTenowere isolated from human hamstring tendon. Presence of insulin receptor beta (INSR-β) on normal tendon tissues and the hTeno monolayer culture were analyzed by immunofluorescence staining. The presence of Glucose Transporter Type 1 (GLUT1) and Glucose Transporter Type 4 (GLUT4) on the hTeno monolayer culture were also analyzed by immunofluorescence staining. Primary hTeno were treated with 0.008, 0.08, 0.8 and 8.0 µM of TNF-α, with and without insulin supplement. Outcome measures include 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl) amino]-2-deoxy-d-glucose (2-NBDG) assay to determine the glucose uptake activity; colourimetric total collagen assay to quantify the total collagen expression levels; COL-I ELISA assay to measure the COL-I expression levels and real-time qPCR to analyze the mRNA gene expressions levels of Scleraxis (SCX), Mohawk (MKX), type I collagen (COL1A1), type III collagen (COL3A1), matrix metalloproteinases (MMP)-9 and MMP-13 in hTeno when treated with TNF-α. Apoptosis assay for hTeno induced with TNF-α was conducted using Annexin-V FITC flow cytometry analysis.

Results

Immunofluorescence imaging showed the presence of INSR-β on the hTeno in the human Achilles tendon tissues and in the hTeno in monolayer culture. GLUT1 and GLUT4 were both positively expressed in the hTeno. TNF-α significantly reduced the insulin-mediated 2-NBDG uptake in all the tested concentrations, especially at 0.008 µM. Total collagen expression levels and COL-I expression levels in hTeno were also significantly reduced in hTeno treated with 0.008 µM of TNF-α. The SCX, MKX and COL1A1 mRNA expression levels were significantly downregulated in all TNF-α treated hTeno, whereas the COL3A1, MMP-9 and MMP-13 were significantly upregulated in the TNF–α treated cells. TNF-α progressively increased the apoptotic cells at 48 and 72 h.

Conclusion

At 0.008 µM of TNF-α, an IR condition was induced in hTeno, supported with the significant reduction in glucose uptake, as well as significantly reduced total collagen, specifically COL-I expression levels, downregulation of candidate tenogenic markers genes (SCX and MKX), and upregulation of ECM catabolic genes (MMP-9 and MMP-13). Development of novel IR model in hTeno provides an insight on how tendon homeostasis could be affected and can be used as a tool for further discovering the effects on downstream molecular pathways, as the implication for diabetic tendinopathy.

The expression of embryonic globin mRNA in a severely anemic mouse model induced by treatment with nitrogen-containing bisphosphonate

Background

Mammalian erythropoiesis can be divided into two distinct types, primitive and definitive, in which new cells are derived from the yolk sac and hematopoietic stem cells, respectively. Primitive erythropoiesis occurs within a restricted period during embryogenesis. Primitive erythrocytes remain nucleated, and their hemoglobins are different from those in definitive erythrocytes. Embryonic type hemoglobin is expressed in adult animals under genetically abnormal condition, but its later expression has not been reported in genetically normal adult animals, even under anemic conditions. We previously reported that injecting animals with nitrogen-containing bisphosphonate (NBP) decreased erythropoiesis in bone marrow (BM). Here, we induced severe anemia in a mouse model by injecting NBP injection in combination with phenylhydrazine (PHZ), and then we analyzed erythropoiesis and the levels of different types of hemoglobin.

Methods

Splenectomized mice were treated with NBP to inhibit erythropoiesis in BM, and with PHZ to induce hemolytic anemia. We analyzed hematopoietic sites and peripheral blood using morphological and molecular biological methods.

Results

Combined treatment of splenectomized mice with NBP and PHZ induced critical anemia compared to treatment with PHZ alone, and numerous nucleated erythrocytes appeared in the peripheral blood. In the BM, immature CD71-positive erythroblasts were increased, and extramedullary erythropoiesis occurred in the liver. Furthermore, embryonic type globin mRNA was detected in both the BM and the liver. In peripheral blood, spots that did not correspond to control hemoglobin were observed in 2D electrophoresis. ChIP analyses showed that KLF1 and KLF2 bind to the promoter regions of β-like globin. Wine-colored capsuled structures were unexpectedly observed in the abdominal cavity, and active erythropoiesis was also observed in these structures.

Conclusion

These results indicate that primitive erythropoiesis occurs in adult mice to rescue critical anemia because primitive erythropoiesis does not require macrophages as stroma whereas macrophages play a pivotal role in definitive erythropoiesis even outside the medulla. The cells expressing embryonic hemoglobin in this study were similar to primitive erythrocytes, indicating the possibility that yolk sac-derived primitive erythroid cells may persist into adulthood in mice.

Electronic supplementary material

The online version of this article (doi:10.1186/s12878-016-0041-0) contains supplementary material, which is available to authorized users.

ADVANCES IN THE USE OF STEM CELLS IN ORTHOPEDICS

Primordial cells or stem cells are multipotent undifferentiated cells with the capacity to originate any type of cell in the organism. They may have their origins in the blastocyst and thus are classified as embryonic, or tissues developed in fetuses, newborns or adults and thus are known as somatic stem cells. Bone marrow is one of the main locations for isolating primordial cells, and there are two lineages: hematopoietic and mesenchymal progenitor cells. There are several uses for these undifferentiated cells in orthopedics, going from cartilaginous lesions in osteoarthrosis, osteochondritis dissecans and patellar chondromalacia, to bone lesions like in pseudarthrosis or bone losses, or nerve lesions like in spinal cord trauma. Studying stem cells is probably the most promising field of study of all within medicine, and this is shortly going to revolutionize all medical specialties (both clinical and surgical) and thus provide solutions for diseases that today are difficult to deal with.

Mechanical strain using 2D and 3D bioreactors induces osteogenesis: implications for bone tissue engineering

Fracture healing is a complicated process involving many growth factors, cells, and physical forces. In cases, where natural healing is not able, efforts have to be undertaken to improve healing. For this purpose, tissue engineering may be an option. In order to stimulate cells to form a bone tissue several factors are needed: cells, scaffold, and growth factors. Stem cells derived from bone marrow or adipose tissues are the most useful in this regard. The differentiation of the cells can be accelerated using mechanical stimulation. The first part of this chapter describes the influence of longitudinal strain application. The second part uses a sophisticated approach with stem cells on a newly developed biomaterial (Sponceram) in a rotating bed bioreactor with the administration of bone morphogenetic protein-2. It is shown that such an approach is able to produce bone tissue constructs. This may lead to production of larger constructs that can be used in clinical applications.

Use of genetically modified mesenchymal stem cells to treat neurodegenerative diseases

The transplantation of mesenchymal stem cells (MSCs) for treating neurodegenerative disorders has received growing attention recently because these cells are readily available, easily expanded in culture, and when transplanted, survive for relatively long periods of time. Given that such transplants have been shown to be safe in a variety of applications, in addition to recent findings that MSCs have useful immunomodulatory and chemotactic properties, the use of these cells as vehicles for delivering or producing beneficial proteins for therapeutic purposes has been the focus of several labs. In our lab, the use of genetic modified MSCs to release neurotrophic factors for the treatment of neurodegenerative diseases is of particular interest. Specifically, glial cell-derived neurotrophic factor (GDNF), nerve growth factor (NGF), and brain derived neurotrophic factor (BDNF) have been recognized as therapeutic trophic factors for Parkinson's, Alzheimer's and Huntington's diseases, respectively. The aim of this literature review is to provide insights into: (1) the inherent properties of MSCs as a platform for neurotrophic factor delivery; (2) the molecular tools available for genetic manipulation of MSCs; (3) the rationale for utilizing various neurotrophic factors for particular neurodegenerative diseases; and (4) the clinical challenges of utilizing genetically modified MSCs.

The effect of a polyurethane-based reverse thermal gel on bone marrow stromal cell transplant survival and spinal cord repair

Cell therapy for nervous tissue repair is limited by low transplant survival. We investigated the effects of a polyurethane-based reverse thermal gel, poly(ethylene glycol)-poly(serinol hexamethylene urethane) (ESHU) on bone marrow stromal cell (BMSC) transplant survival and repair using a rat model of spinal cord contusion. Transplantation of BMSCs in ESHU at three days post-contusion resulted in a 3.5-fold increase in BMSC survival at one week post-injury and a 66% increase in spared nervous tissue volume at four weeks post-injury. These improvements were accompanied by enhanced hindlimb motor and sensorimotor recovery. In vitro, we found that ESHU protected BMSCs from hydrogen peroxide-mediated death, resulting in a four-fold increase in BMSC survival with two-fold fewer BMSCs expressing the apoptosis marker, caspase 3 and the DNA oxidation marker, 8-oxo-deoxyguanosine. We argue that ESHU protected BMSCs transplanted is a spinal cord contusion from death thereby augmenting their effects on neuroprotection leading to improved behavioral restoration. The data show that the repair effects of intraneural BMSC transplants depend on the degree of their survival and may have a widespread impact on cell-based regenerative medicine.

Regulation of human hematopoietic stem cell self-renewal by the microenvironment's control of retinoic acid signaling

The high expression of aldehyde dehydrogenase 1, also known as retinaldehyde dehydrogenase, by hematopoietic stem cells (HSCs) suggests an important role for retinoic acid (RA) signaling in determining the fate of these cells. We found that primitive human bone marrow-derived CD34(+)CD38(-) cells not only highly express aldehyde dehydrogenase 1, but also the RA receptor α. Despite the up-regulation of early components of RA signaling, the downstream pathway remained inactive in the primitive CD34(+)CD38(-) cells. Primitive hematopoietic cells rapidly undergo terminal differentiation when cultured away from their microenvironment; however, we found that inhibition of RA signaling maintained their primitive phenotype and function, and promoted their self-renewal. HSCs reside in a complex microenvironment that enforces the balance between self-renewal and differentiation. The exact physiologic mechanisms by which the niche controls HSC fate remain elusive. The embryonic gonadal microenvironment has recently been shown to determine germ-cell fate by degrading RA through expression of the P450 retinoid-inactivating enzyme CYP26B1. We found that the bone marrow microenvironment similarly can control primitive hematopoietic cell fate via modulation of retinoid bioavailability. Accordingly, we found that bone marrow stromal cell CYP26 was also able to inactivate retinoids in serum, preventing RA signaling. Thus, primitive hematopoietic cells appear to be intrinsically programmed to undergo RA-mediated differentiation unless prevented from doing so by bone marrow niche CYP26. Modulation of RA signaling also holds promise for clinical HSC expansion, a prerequisite for the wide-scale use of these cells in regenerative medicine and gene therapy.

Prospective isolation of mesenchymal stem cells from human bone marrow using novel antibodies directed against Sushi domain containing 2

Several strategies have been developed to facilitate the prospective isolation of bone marrow-derived mesenchymal stem/stromal cells (BM-MSCs) based on the selective expression or absence of surface markers. Recently, we described the monoclonal antibodies W3D5 and W5C5, which selectively react with BM-MSCs, but not with hematopoietic cells. Both antibodies showed an identical reactivity pattern, indicating that they may recognize the same molecule. To identify the cognate antigen, cultured MSCs were sorted for cells expressing either very high levels of W5C5/W3D5 antigen or for cells which were negative for this antigen. Further processing of these cells for microarray analysis revealed a 20-fold enrichment of the type 1 integral membrane protein Sushi domain containing 2 (SUSD2) in the in W5C5(+) subset. To confirm the identity of the W5C5/W3D5 antigen to SUSD2, HEK293 cells were transfected with the full-length coding sequence of human SUSD2 followed by reactivity analysis of W5C5 and W3D5 antibodies with the transfected line. Flow cytometric analysis showed that both antibodies selectively recognized HEK293/huSUSD2 cells, but not the parental cell line. In line with this, SUSD2 siRNA treatment of SUSD2(+) WERI-RB-1 retinoblastoma cells reduced the expression levels of W3D5 and W5C5 antigens to ~39% and 37%, respectively. Finally, FACSorting and colony assays revealed that only SUSD2(+), but not SUSD2(-) BM cells give rise to colony-forming units-fibroblasts and are able to differentiate into osteoblasts, adipocytes, and chondrocytes. In conclusion, we identified SUSD2 as a novel and specific marker for the prospective isolation of BM-MSCs.

Behaviour of rat-cultured dental pulp cells in three-dimensional collagen type-1 gel in vitro and in vivo

The purpose of this study was to investigate the growth and differentiation potential of dental pulp cells (DPCs) in three-dimensional (3-D) collagen type-1 scaffold in vitro and in vivo. Third passage DPCs were cultured in a 3-D collagen and expression of both bone- or dentin-related mRNA (alkaline phosphatase (ALP), bone sialoprotein (BSP) and osteopontin (OPN)) and morphological changes evaluated in vitro. In the in vivo study, two types of grafts were transplanted into the rectus abdominus muscles of rats and harvested after 7 days: DPCs in α-minimal essential medium and DPCs mixed with a collagen gel. ALP, BSP and OPN were used as primary antibodies for immunohistochemical study. Histological and immunohistochemical results showed that DPCs in collagen gel were spindle shaped and showed significantly greater expression of ALP, BSP and OPN in vitro than the controls. Transplanted DPCs in collagen type-1 gel showed greater positive immunoreactivity for ALP, BSP and OPN than the controls. It was concluded that the collagen gel scaffold encouraged the differentiation of DPCs into osteoblastic cells.

Clinical implications of activated leukocyte cell adhesion molecule expression in breast cancer

In the study, we enrolled 150 breast cancer cases to investigate the expression status of activated leukocyte cell adhesion molecule (ALCAM), and the relationships between ALCAM expression and clinical-pathological characteristics and prognosis of breast cancer. It was observed that ALCAM was expressed at higher levels in breast cancer tissue compared to levels observed for tumor-adjacent tissue. Compared to cancers with low membranous ALCAM expression, cancers with high membranous ALCAM expression were prone to lymph node metastasis (χ2=15.910, P=0.010) and metastasis in general (χ2=5.211, P=0.029). High cytoplasmic ALCAM expression was noticeably correlated with local recurrence (χ2=7.379, P=0.012), especially for short-term recurrence (interval<2 years) (χ2=5.562, P=0.037), while not associated to long-term local recurrence (interval>2 years). The content of ALCAM protein is closely associated with the expression of estrogen receptor (ER) (P=0.024). The disease-free survival of patients with high cytoplasmic ALCAM expression was significantly shorter compared to the cases with low cytoplasmic ALCAM expression (P=0.036). In conclusion, ALCAM expressed at high levels in breast cancer. High membranous expression of ALCAM probably resulted in weakened adherent ability and metastasis. In addition, high cytoplasmic ALCAM expression strengthened invasive ability of malignant cells and then promoted tumor development.

Hematopoietic stromal cells and megakaryocyte development

The hematopoietic microenvironment, and in particular the hematopoietic stromal cell element, are intimately involved in megakaryocyte development. The process of megakaryocytopoiesis occurs within a complex bone marrow microenvironment where adhesive interactions, chemokines, as well as cytokines play a pivotal role. Here we review the effect of stromal cells and cytokines on megakaryocytopoiesis with the aim of exploring new therapeutic strategies for platelet recovery after hematopoietic stem cell transplantation (HSCT).

GLI2 transcription factor mediates cytokine cross-talk in the tumor microenvironment

Tumor cells interact with their surrounding microenvironment to survive and persist within the host. Cytokines play a key role in regulating this crosstalk between malignant cells and surrounding cells in the microenvironment. Although this phenomenon is clearly established, the molecular mechanisms mediating this cellular event remain elusive. Here, using as a model bone marrow stromal cells, we describe a novel signaling mechanism initiated by CCL5 in these cells leading to up-regulation of immunoglobulin secretion by malignant B cells. CCL5 increases IL-6 expression and secretion in bone marrow stromal cells. IL-6 in turn induces Ig secretion by malignant B cells. Analysis of the mechanism reveals that CCL5 signaling induces GLI2 through a PI3K-AKT-IκBα-p65 pathway and requires GLI2 transcriptional activity to modulate IL-6 expression and Ig secretion in vitro and in vivo. Together, these results identify a novel signaling pathway mediating the stromal-cancer cell interactions, leading to increased Ig production by malignant cells.

Functional polymorphisms in CD166/ALCAM gene associated with increased risk for breast cancer in a Chinese population

Activated Leukocyte Cell Adhesion Molecules (ALCAM, also called CD166, MEMD) are cell surface immunoglobulins that are considered to be prognostic markers for breast cancer. CD166/ALCAM has gained increasing attention because of its significant association with tumor progression and the metastatic spread of breast cancer. Two polymorphisms have been identified in the CD166/ALCAM gene: 5'UTR C/T (rs6437585) and 3'UTR A/G (rs11559013). We analyzed the genotypes of 1033 individuals with breast cancer, and 1116 controls; odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using logistic regression. The effects and functions of polymorphisms were examined using luciferase gene expression assays and real-time PCR analyses. Our data demonstrated that individuals with the rs6437585 CT + TT genotype had an OR of 1.38 (95% CI, 1.11-1.72) for developing breast cancer, compared to those with the CC genotype. The T allele increased the risk of breast cancer in a dose-dependent manner (P (trend) < 0.001). However, there were no significant differences found between cases and controls at the rs11559013 A/G site. Additional experiments that we performed, which focused on reporter gene expression driven by CD166/ALCAM promoters, demonstrated that the presence of an rs6437585 T allele led to greater transcriptional activity than the rs6437585 C allele. This was consistent with the increased cancer risk that we observed in our case-control analysis.

Functional recovery after hematic administration of allogenic mesenchymal stem cells in acute ischemic stroke in rats

Hematic administration of bone marrow-derived mesenchymal stem cells (MSCs) in acute ischemic stroke may not only be an effective reparative treatment but also a brain protective therapy that improves neurological recovery. Our purpose was to study whether either i.v. or intracarotid (i.c.) administration of allogenic MSCs during the acute phase were effective in improving neurological recovery and decreasing brain damage in an experimental rat model. In a model of permanent middle cerebral artery occlusion (pMCAO), we analyzed: neurological evaluation; MSCs migration and implantation; interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) levels; lesion volume; cell death; cellular proliferation; vascular endothelial growth factor (VEGF) expression and blood vessel number. Regardless of the administration route, treated groups showed better neurological recovery, without significant differences between the two groups. Migration and implantation of MSCs in the lesion area was observed in animals receiving i.c. but not i.v. treatment. The highest cytokine values were observed in the i.v. MSCs and i.c. control groups, and these levels were significantly different from the corresponding i.v. control and i.c. MSCs groups, respectively. In addition, there were significant differences between the i.v. MSCs and i.c. MSCs groups in IL-6 levels. Neither treatment reduced infarction volume. However, cell death, measured as TUNEL+ cells was decreased with significant differences between control groups. BrdU+ cells were also significantly increased in the peri-infarct zone at 14 days. VEGF expression was significantly higher in the i.c. MSCs group than in the i.c. control group and blood vessel number was significantly higher in treated groups than control groups with significant differences in the peri-infarct zone at 14 days. We conclude that allogenic MSCs administration shows therapeutic efficacy in our acute ischemic stroke model. Both routes demonstrably improved neurological recovery and provided brain protection.

Development and performance analysis of PCL/silica nanocomposites for bone regeneration

In the present article, several developments of biocomposites containing silica nanoparticles intended for bone regeneration are reported. Nanocomposites of poly(ε-caprolactone) (PCL) and silica, in which either the silica nanoparticles or the PCL have been modified in order to improve interfacial adhesion through chemical graft between the phases are hereafter described. The composites are characterized with respect to their chemical-physical and mechanical properties. Their biocompatibility and capacity to induce the osteoblastic phenotype in human bone marrow mesenchymal stem cells have been assessed.

Osteogenic differentiation of bone marrow stromal cells on poly(epsilon-caprolactone) nanofiber scaffolds

Nanofiber poly(epsilon-caprolactone) (PCL) scaffolds were fabricated by electrospinning, and their ability to enhance the osteoblastic behavior of marrow stromal cells (MSCs) in osteogenic media was investigated. MSCs were isolated from Wistar rats and cultured on nanofiber scaffolds to assess short-term cytocompatibility and long-term phenotypic behavior. Smooth PCL substrates were used as control surfaces. The short-term cytocompatibility results indicated that nanofiber scaffolds supported greater cell adhesion and viability compared with control surfaces. In osteogenic conditions, MSCs cultured on nanofiber scaffolds also displayed increased levels of alkaline phosphatase activity for 3 weeks of culture. Calcium phosphate mineralization was substantially accelerated on nanofiber scaffolds compared to control surfaces as indicated through von Kossa and calcium staining, scanning electron microscopy and energy-dispersive X-ray spectroscopy. Increased levels of intra- and extracellular levels of osteocalcin and osteopontin were observed on nanofiber scaffolds using immunofluorescence techniques after 3 weeks of culture. These results demonstrate the enhanced tissue regeneration property of nanofiber scaffolds, which may be of potential use for engineering osteogenic scaffolds for orthopedic applications.

Isolation and characterization of endosteal niche cell populations that regulate hematopoietic stem cells

The endosteal niche is critical for the maintenance of hematopoietic stem cells (HSCs). However, it consists of a heterogeneous population in terms of differentiation stage and function. In this study, we characterized endosteal cell populations and examined their ability to maintain HSCs. Bone marrow endosteal cells were subdivided into immature mesenchymal cell-enriched ALCAM(-)Sca-1(+) cells, osteoblast-enriched ALCAM(+)Sca-1(-), and ALCAM(-)Sca-1(-) cells. We found that all 3 fractions maintained long-term reconstitution (LTR) activity of HSCs in an in vitro culture. In particular, ALCAM(+)Sca-1(-) cells significantly enhanced the LTR activity of HSCs by the up-regulation of homing- and cell adhesion-related genes in HSCs. Microarray analysis showed that ALCAM(-)Sca-1(+) fraction highly expressed cytokine-related genes, whereas the ALCAM(+)Sca-1(-) fraction expressed multiple cell adhesion molecules, such as cadherins, at a greater level than the other fractions, indicating that the interaction between HSCs and osteoblasts via cell adhesion molecules enhanced the LTR activity of HSCs. Furthermore, we found an osteoblastic marker(low/-) subpopulation in ALCAM(+)Sca-1(-) fraction that expressed cytokines, such as Angpt1 and Thpo, and stem cell marker genes. Altogether, these data suggest that multiple subsets of osteoblasts and mesenchymal progenitor cells constitute the endosteal niche and regulate HSCs in adult bone marrow.

Regulation of Lymphoid and Myeloid Leukemic Cell Survival: Role of Stromal Cell Adhesion Molecules

Several laboratories have documented the necessity for direct contact of lymphoid and myeloid leukemic cells with bone marrow stromal cells for optimal survival. Subsequent studies have identified various stromal cell adhesion molecules and soluble factors that facilitate survival through leukemic cell anti-apoptotic signal transduction pathways. This report provides an overview of enhanced leukemic cell survival through adhesive interactions with bone marrow expressed molecules. In addition, we describe the establishment of cloned murine stromal cell lines engineered to constitutively express human VCAM-1 protein on their surface. These stromal cell lines will be useful in studies aimed at better understanding the specific contribution of VCAM-1: VLA-4 signaling in maintenance of residual leukemic disease.

Human adult mesenchymal stem cells improve rat spatial cognitive function after systemic hemorrhagic shock

The aim of the present study was to examine whether a single infusion of human adult mesenchymal stem cells (hMSC) has protective effects on rat cognitive functions after systemic hemorrhagic shock. Systemic hemorrhagic rat shock model of pronounced (30 min) systemic hypotension [30-40 mmHg mean arterial blood pressure (MABP) reduction] was used to induce cerebral oligemia. Immediately after the experimental transient hypotension period ended, human processed lipoaspirate-derived mesenchymal stem cells (hMSC, 1 x 10(6)) were administered via the femoral vein. Rats were tested in relation to their cognitive spatial abilities using the Morris water maze before and 3 days after transient oligemia and with/without hMSC transplantation. Immunohistological investigations were performed with respect to apoptosis and BrdU staining. A clear functional improvement was observed in the rats' spatial cognitive abilities after hypotension and subsequent hMSC transplantation. In the hypotension group, hMSC infusion reduced the mortality from 50% to 25%. Six days after hMSC administration and hypotension, we did not detect any BrdU-labeled cells in rat brain, lung, and liver; however, BrdU-positive cells were found in spleen. No signs of cerebral apoptosis were observed. We conclude from this study that hMSCs derived from peripheral blood could be an important cell source to improve functional outcome after transient cerebral oligemia. Identifying the underlying mechanism for this, however, should be the subject of further investigations.

Oncologic trogocytosis of an original stromal cells induces chemoresistance of ovarian tumours

BACKGROUND

The microenvironment plays a major role in the onset and progression of metastasis. Epithelial ovarian cancer (EOC) tends to metastasize to the peritoneal cavity where interactions within the microenvironment might lead to chemoresistance. Mesothelial cells are important actors of the peritoneal homeostasis; we determined their role in the acquisition of chemoresistance of ovarian tumours.

METHODOLOGY/PRINCIPAL FINDINGS

We isolated an original type of stromal cells, referred to as "Hospicells" from ascitis of patients with ovarian carcinosis using limiting dilution. We studied their ability to confer chemoresistance through heterocellular interactions. These stromal cells displayed a new phenotype with positive immunostaining for CD9, CD10, CD29, CD146, CD166 and Multi drug resistance protein. They preferentially interacted with epithelial ovarian cancer cells. This interaction induced chemoresistance to platin and taxans with the implication of multi-drug resistance proteins. This contact enabled EOC cells to capture patches of the Hospicells membrane through oncologic trogocytosis, therefore acquiring their functional P-gp proteins and thus developing chemoresistance. Presence of Hospicells on ovarian cancer tissue micro-array from patients with neo-adjuvant chemotherapy was also significantly associated to chemoresistance.

CONCLUSIONS/SIGNIFICANCE

This is the first report of trogocytosis occurring between a cancer cell and an original type of stromal cell. This interaction induced autonomous acquisition of chemoresistance. The presence of stromal cells within patient's tumour might be predictive of chemoresistance. The specific interaction between cancer cells and stromal cells might be targeted during chemotherapy.

Isolation of functionally distinct mesenchymal stem cell subsets using antibodies against CD56, CD271, and mesenchymal stem cell antigen-1

BACKGROUND

Conventionally, mesenchymal stem cells are functionally isolated from primary tissue based on their capacity to adhere to a plastic surface. This isolation procedure is hampered by the unpredictable influence of co-cultured hematopoietic and/or other unrelated cells and/or by the elimination of a late adhering mesenchymal stem cells subset during removal of undesired cells. To circumvent these limitations, several antibodies have been developed to facilitate the prospective isolation of mesenchymal stem cells. Recently, we described a panel of monoclonal antibodies with superior selectivity for mesenchymal stem cells, including the monoclonal antibodies W8B2 against human mesenchymal stem cell antigen-1 (MSCA-1) and 39D5 against a CD56 epitope, which is not expressed on natural killer cells.

DESIGN AND METHODS

Bone marrow derived mesenchymal stem cells from healthy donors were analyzed and isolated by flow cytometry using a large panel of antibodies against surface antigens including CD271, MSCA-1, and CD56. The growth of mesenchymal stem cells was monitored by colony formation unit fibroblast (CFU-F) assays. The differentiation of mesenchymal stem cells into defined lineages was induced by culture in appropriate media and verified by immunostaining.

RESULTS

Multicolor cell sorting and CFU-F assays showed that mesenchymal stem cells were approximately 90-fold enriched in the MSCA-1(+)CD56(-) fraction and approximately 180-fold in the MSCA-1(+)CD56(+) fraction. Phenotype analysis revealed that the expression of CD10, CD26, CD106, and CD146 was restricted to the MSCA-1(+)CD56(-) mesenchymal stem cells subset and CD166 to MSCA-1(+)CD56(+/-) mesenchymal stem cells. Further differentiation of these subsets showed that chondrocytes and pancreatic-like islets were predominantly derived from MSCA-1(+)CD56(+/-) cells whereas adipocytes emerged exclusively from MSCA-1(+)CD56(-) cells. The culture of single sorted MSCA-1(+)CD56(+) cells resulted in the appearance of phenotypically heterogeneous clones with distinct proliferation and differentiation capacities.

CONCLUSIONS

Novel mesenchymal stem cells subsets with distinct phenotypic and functional properties were identified. Our data suggest that the MSCA-1(+)CD56(+) subset is an attractive starting population for autologous chondrocyte transplantation.

Isolation of osteoprogenitors from murine bone marrow by selection of CD11b negative cells

Selection of cells having the most osteogenic potential is a strategy used in bone tissue engineering. Preclinical studies using murine bone marrow cells must consider the large amount of hematopoietic cells in the adherent fraction. The aim of this study was to enrich a murine bone marrow cell population with osteoprogenitors by using a simple and reliable method. Bone marrow from C57Bl/6 mice was extracted and cells which adhered onto plastic were expanded in primary culture for 14 days. Immunolabeling of the CD11b surface antigen was performed and the CD11b(-) cell fraction was isolated by FACS. Sorted and unsorted populations were analyzed for gene expression of osteoblast differentiation, alkaline phosphatase (AlkP) activity and matrix mineralization capacities. Selection of CD11b(-) cells increased the number of AlkP(+) cells from the plastic adherent fraction from 6.3% +/- 0.8 to 56% +/- 3.3 with a sevenfold increase in AlkP activity. mRNA analysis revealed a significant increase in the CD11b(-) fraction for Osterix (41-fold), RANKL (17-fold), M-CSF (8-fold) and Runx-2 (8-fold). An osteogenic population was obtained with improved capacities to produce a mineralized extracellular matrix in vitro, independently of the presence of glucocorticoids in the culture medium.

Leptin as an endocrine signal in bone

Leptin and its actions in bone came to prominence in 2000, with the publication of two landmark articles identifying a novel interaction between energy and bone homeostasis, as well as a novel hypothalamic circuit to the skeleton. However, they also revealed the dichotomous nature of leptin's effect on the skeleton. Subsequent research has increased understanding of the factors critical to interpretation of the leptin-bone signaling. These include opposing effects in cortical and cancellous bone, central and peripheral effects, involvement of other neural and endocrine factors, and leptin receptor polymorphisms in human populations. It is clear that leptin can markedly influence the regulation of bone mass, and that study of this pathway continues to increase our knowledge of the biology of skeletal tissue and its interactions with other tissues. However, this relationship is complex and requires careful interpretation.

Multipotent properties of myofibroblast cells derived from human placenta

Human uterine fibroblasts (HuF) isolated from the maternal part (decidua parietalis) of a term placenta provide a useful model of in vitro cell differentiation into decidual cells (decidualization, a critical process for successful pregnancy). After isolation, the cells adhere to plastic and have either a small round or spindle-shaped morphology that later changes into a flattened pattern in culture. HuF robustly proliferate in culture until passage 20 and form colonies when plated at low densities. The cells express the mesenchymal cell markers fibronectin, integrin-beta1, ICAM-1 (CD54), and collagen I. Flow cytometry of HuF has detected the presence of CD34, a marker of the hematopoietic stem cell lineage, and an absence of CD10, CD11b/Mac, CD14, CD45, and HLA type II. Furthermore, they also express the pluripotency markers SSEA-1, SSEA-4, Oct-4, Stro-1, and TRA-1-81 as detected by confocal microscopy. Treatment for 14-21 days with differentiation-inducing media leads to the differentiation of HuF into osteoblasts, adipocytes, and chondrocytes. The presence of alpha-smooth muscle actin, calponin, and myosin light-chain kinase in cultured HuF implies their similarity to myofibroblasts. Treatment of the HuF with dimethyl sufoxide causes reversion to the spindle-shaped morphology and a loss of myofibroblast characteristics, suggesting a switch into a less differentiated phenotype. The unique abilities of HuF to exhibit multipotency, even with myofibroblast characteristics, and their ready availability and low maintenance requirements make them an interesting cell model for further exploration as a possible tool for regenerative medicine.

Transdifferentiation of bone marrow stromal cells into Schwann cell phenotype using progesterone as inducer

Bone marrow stromal cells (BMSCs) were reported to transdifferentiate into Schwann cells by a two-stage protocol, using beta-mercaptoethanol and retinoic acid (BME-RA) as preinducers (preinduction stage: PS) and platelet derived growth factor (PDGF), basic fibroblast growth factor (bFGF), forskolin (FSK) and heregulin (HRG) as inducers (induction stage: IS). In this study, six groups were used, group one was used as control (PS: BME-RA; IS: PDGF, bFGF, FSK and HRG). In group 2, the preinducer was similar to group 1, and in the induction stage, progesterone replaced HRG. In groups 3 and 4, the preinducer was progesterone; and at the induction stage, the inducer was similar to groups 1 and 2. Accordingly, in groups 5 and 6, the preinducer was FSK. The immunohistochemical differentiation markers were S-100 and P0, and RT-PCR markers were OCT-4 and P0 at the preinduction stage, while at the induction stage P0 and NeuroD were used. The results of the study showed that S-100 was expressed in the groups after the induction stage, however, P0 was not expressed in any group. There was not any significant difference between the percentage of S100 positive cells in the 1st and 2nd groups. P0 was expressed at the mRNA level in the undifferentiated BMSCs and in the 3rd and 4th groups after the preinduction and the induction stages. The conclusion of this study is that progesterone can induce BMSCs into Schwann cell phenotype.

Stem cells ameliorate EAE via an indoleamine 2,3-dioxygenase (IDO) mechanism

Syngeneic, pluripotent Lin(-)Sca1(+) bone marrow stem cells (SC), transferred to mice with experimental autoimmune encephalomyelitis, a model of multiple sclerosis, enhanced recovery, prevented relapses and promoted myelin repair. SC-treated mice showed elevated interferon-gamma production and induction of indoleamine 2,3-dioxygenase (IDO) in CD11c(+) dendritic cells (DC). IDO induction was specific since in the presence of IDO-producing CD11c(+) DC, PLP stimulated T cell proliferation was inhibited and the IDO-inhibitor, 1-MT, abrogated the SC effect. Relapse prevention during chronic disease correlated with decreased responsiveness to PLP(178-191) and MBP(85-99). Thus, pluripotent SC induce IDO in DC leading to inhibition of antigen reactivity and spreading in EAE.

Gene expression analysis at the single cell level using the human bone marrow stromal cell as a model: sample preparation methods

Recent advances in molecular technology, including gene expression microarray analysis, have allowed researchers to examine global patterns of gene expression at high resolution in populations of cultured cells or tissues. Although these techniques can be applied with great sophistication and are useful for address ing many biological questions in cell populations, it is also of great value to assess gene expression at the level of the single cell. This can be achieved by one of two different approaches: (1) specific cell types can be purified from heterogeneous tissues or cultures using immunological methods such as fluorescence-based or magnetic cell sorting or laser capture microdissection, followed by amplification of target cell nucleic acids, and analysis of expressed genes; or (2) immunohisto-chemical studies and in situ expression studies on identical tissue sections can be used to identify genes or sets of genes whose expression correlates with a morpho logically or immunochemically distinct cell-type. Using either approach, the target cell types are identified by their morphological or immunohistochemical properties. This chapter is a primer on using single cell gene expression technology to study human bone marrow stromal cells that express mixed lineage markers. Cytomorphological, cytochemical, and immunocytochemical methods as well as gene expression microarray studies demonstrated that single stromal cells simulta neously express markers associated with osteoblast, fibroblast, muscle, and adi-pocyte differentiation, suggesting that these stromal cells are mesenchymal progenitor cells that have multilineage differentiation capacity. These data charac terize human bone marrow stromal cells as adult stem cells. Because of their pluripotent nature, single cell gene expression technology is particularly critical for characterizing and developing the therapeutic potential of these cells.

Downregulation of extracellular matrix-related gene clusters during osteogenic differentiation of human bone marrow- and adipose tissue-derived stromal cells

Bone marrow- and adipose tissue-derived stromal cells (BMSCs and ASCs, respectively) exhibit a similar capacity for osteogenic differentiation in vitro, but it is unclear whether they share a common differentiation process, because they originate from different tissues. The aim of this study was to explore BMSC and ASC osteogenic differentiation by focusing on the expression of extracellular matrix-related genes (ECMGs), which play a crucial role in osteogenesis and bone tissue regeneration in vivo. We characterized the gene expression profiles of BMSCs and ASCs using a custom complementary deoxyribonucleic acid microarray containing 55 ECMGs. Undifferentiated BMSCs and ASCs actively expressed a wide range of ECMGs. Once BMSCs and ASCs were placed in an osteogenic differentiation medium, 24 and 17 ECMGs, respectively, underwent considerable downregulation over the course of the culture period. The remaining genes were maintained at a similar expression level to corresponding uninduced cell cultures. Although the suppression phenomenon was consistent irrespective of stromal cell origin, collagen (COL)2A1, COL6A1, COL9A1, parathyroid hormone receptor, integrin (INT)-beta3, and TenascinX genes were only downregulated in osteogenic BMSCs, whereas COL1A2, COL3A1, COL4A1, COL5A2, COL15A1, osteopontin, osteonectin, and INT-beta1 genes were only downregulated in osteogenic ASCs. During this time period, cell viability was sustained, suggesting that the observed downregulation did not occur by selection and elimination of unfit cells from the whole cell population. These data suggest that osteogenically differentiating BMSCs and ASCs transition away from a diverse gene expression pattern, reflecting their multipotency toward a configuration specifically meeting the requirements of the target lineage. This change may serve to normalize gene expression in mixed populations of stem cells derived from different tissues.

Prospective isolation and characterization of mesenchymal stem cells from human placenta using a frizzled-9-specific monoclonal antibody

We have recently shown that frizzled-9 (FZD9, CD349) is expressed on the cell surface of cultured mesenchymal stromal cells (MSC) derived from the human bone marrow (BM) and chorionic placenta (PL). To study whether FZD9 is also a marker for naive mesenchymal stem cells (MSC), we analyzed the expression pattern of FZD9 on freshly isolated PL cells and determined the clonogenic potential of isolated FZD9(+) cells using the colony-forming units-fibroblastic (CFU-F) assay. About 0.2% of isolated PL cells were positive for FZD9. Two-color analysis revealed that FZD9(+) PL cells uniformly express CD9, CD63, and CD90, but are heterogeneous for CD10, CD13, and CD26 expression. In contrast to BM-derived MSC, PL-derived MSC expressed only low levels of CD271. Colony assays of sorted cells showed that clonogenic CFU-F reside exclusively in the FZD9(+) but not in the FZD9(-) fraction. Further analysis revealed that CFU-F were enriched by 60-fold in the FZD9(+)CD10(+)CD26(+) fraction but were absent in the FZD9(+)CD10(-)CD26(-) population. Cultured FZD9(+) cells expressed the embryonic stem cell makers Oct-4 and nanog as well as SSEA-4 and TRA1-2-49/6E. In addition, they could be differentiated into functional adipocytes and osteoblasts. This report describes for the first time that FZD9 is a novel and specific marker for the prospective isolation of MSC from human term PL.

Proteomics strategy based on liquid-phase IEF and 2-D DIGE: application to bone marrow mesenchymal progenitor cells

Global comparative proteomics is a promising new approach with broad application in basic and clinical biological science. Recent advances include the development of 2-D DIGE, a proteomic equivalent to mRNA differential display, in which differentially labeled samples are multiplexed and analyzed by high-resolution 2-DE. This study presents a new 2-D DIGE protocol, in which complex protein samples from normal and leukemic human bone marrow mesenchymal progenitor cells were used as model samples for a novel combination of liquid-phase IEF with 2-D DIGE. Using liquid-phase IEF, the normal and leukemic cells were pre-fractionated into five subproteomes after multiplexing but prior to DIGE. Under these conditions, 2-D DIGE resolved >5000 protein-containing spots within the pH range 4.6-7.0. Differential labeling combined with subsequent MALDI-MS/MS identified proteins that were differentially expressed in leukemic cells. This analysis mapped protein identities to 128 mesenchymal progenitor cell proteins with at least one unique peptide match at >95% confidence. Of these proteins, 72 (56%) were expressed more than 1.25-fold higher or lower in leukemic cells compared with normal cells (p<0.05). These data were used to infer gene ontology biological processes that may be altered in leukemic bone marrow mesenchymal progenitor cells.

Expression of Thy 1.2 surface antigen increases significantly during the murine mesenchymal stem cells cultivation period

This study sought to investigate the absence or expression of some surface antigens on murine mesenchymal stem cells (mMSCs) during the cultivation period of primary culture to passage 3 (equivalent to about 15 or 16 population doubling number). For this purpose, bone marrow cells from 6-8-week-old mice (either NMRI or Balb/c) were cultivated in 75-cm(2) culture flask for three successive passages, in each of which the culture was examined for the expression of CD135, CD44, CD31, Thy1.2, CD11b, CD45, CD34, Vcam1, Sca-1, and c-Kit antigens, using flow cytometry. Passage-3 cells from each strain can easily be differentiated into bone and fat, which was indicative of their mesenchymal nature. Our results demonstrated that for each given antigen, the percentages of the cells expressing that antigen had been changed by subcultures. The statistical analysis showed that nearly all differences between the passages were statistically significant. In this term, the expressional changes of Thy 1.2 seemed to be very significant in such a way that the expression increased to about half of the whole population in passage 3. In conclusion, it seems that this antigen could be considered as an enriching antigen for mMSCs population from bone marrow adherent cell culture.