Ultrasound combined with SDF-1α chemotactic microbubbles promotes stem cell homing in an osteoarthritis model.

Osteoarthritis (OA) is a common joint disease in the middle and old age group with obvious cartilage damage, and the regeneration of cartilage is the key to alleviating or treating OA. In stem cell therapy, bone marrow stem cell (BMSC) has been confirmed to have cartilage regeneration ability. However, the role of stem cells in promoting articular cartilage regeneration is severely limited by their low homing rate. Stromal cell-derived factor-1α (SDF-1α) plays a vital role in MSC migration and involves activation, mobilization, homing and retention. So, we aim to develop SDF-1α-loaded microbubbles MB(SDF-1α), and to verify the migration of BMSCs with the effect of ultrasound combined with MB(SDF-1α) in vitro and in vivo. The characteristics of microbubbles and the content of SDF-1α were examined in vitro. To evaluate the effect of ultrasound combined with chemotactic microbubbles on stem cell migration, BMSCs were injected locally and intravenously into the knee joint of the OA model, and the markers of BMSCs in the cartilage were detected. We successfully prepared MB(SDF-1α) through covalent bonding with impressive SDF-1α loading efficacy loading content. In vitro study, ultrasound combined with MB(SDF-1α) group can promote more stem cell migration with highest migrating cell counts, good cell viability and highest CXCR4 expression. In vivo experiment, more BMSCs surface markers presented in the ultrasound combined with MB(SDF-1α) group with or without exogenous BMSCs administration. Hence, ultrasound combined with MB(SDF-1α) could promote the homing of BMSCs to cartilage and provide a novel promising therapeutic approach for OA.

Distinct biological characterization of the CD44 and CD90 phenotypes of cancer stem cells in gastric cancer cell lines.

Recent study implicates that gastric cancer stem cells (CSCs) are capable of generating multiple types of cells to promote tumor growth and heterogeneity important for the development of gastric cancer. However, knowledge is limited regarding the expression and characteristics of marker-positive gastric CSCs. Therefore, gastric CSCs from a series of human gastric cancer cell lines (SNU-5, SNU-16, BGC-823, PAMC-82, MKN-45, and NCI-N87) using four putative CSC surface markers (CD44, CD90, CD133, and epithelial-cell adhesion molecule) were investigated the underlying mechanisms regulating such subpopulations. Only SNU-5 and SNU-16 exhibited independent co-expression of CD44+ and CD90+, which exhibited spheroid-colony formation in vitro and tumor formation in immunodeficient mice. Functional studies revealed that CD44+ cells were more invasive compared with CD90+ cells, whereas CD90+ cells exhibited higher levels of proliferation than CD44+ cells. Furthermore, serial xenotransplantation in mice of CD44+/CD90+ cells derived from SNU-5 and SNU-16 revealed rapid growth of CD90+ cells in subcutaneous lesions and a high metastatic capacity of CD44+ cells in the lung. Mechanistic analyses revealed that CD44+ cells underwent epithelial-to-mesenchymal transition (EMT) following acquisition of mesenchymal features, whereas CD90+ cells enhanced the activation of retinoblastoma phosphorylation at Ser780 and oncogenic cell cycle regulators. The expression of CD44 and CD90 in gastric cancer tissues was associated with distant metastasis and the differentiation state of tumors. These results demonstrated that CD44 and CD90 are specific biomarkers capable of identifying and isolating metastatic and tumorigenic CSCs through their ability to regulate EMT and the cell cycle in gastric cancer cell lines.

Alcohol-Induced Interleukin-17 Expression Causes Murine Lung Fibroblast-to-Myofibroblast Transdifferentiation via Thy-1 Down-Regulation.

BACKGROUND: Alcohol exposure induces TGFß1 and renders the lung susceptible to injury and disrepair. We determined that TGFß1 regulates myofibroblast differentiation through the loss of Thy-1 expression and consequent induction of α-SMA. TGFß1 is important for T helper 17 (Th17) differentiation and IL-17 secretion, which in turn participates in tissue repair. We hypothesized that alcohol induces Th17 differentiation via TGFß1 and that IL-17 produced by these cells contributes to the development of profibrotic lung myofibroblasts. METHODS: Primary lung fibroblasts (PLFs) were treated with alcohol, TGFß1, and IL-17 and then analyzed for Thy-1 expression and cell morphology. Naïve and Th17-polarized CD4+ T cells were exposed to alcohol and assessed for IL-17 expression. CD4+ T cells from alcohol-fed mice were analyzed for Th17 and IL-17 expression. Lungs of control-fed, bleomycin-treated and alcohol-fed, bleomycin-treated mice were analyzed for IL-17 protein expression. RESULTS: Alcohol-treated PLFs expressed lower levels of Thy-1 than untreated cells. TGFß1 or IL-17 exposure suppressed PLF Thy-1 expression. When administered together, TGFß1 and IL-17 additively down-regulated Thy-1 expression. Exposure of naïve and Th17-polarized CD4+ T cells to alcohol induced the Th17 phenotype and augmented their production of IL-17. CD4+ Th17+ levels are elevated in the peripheral compartment but not in the lungs of alcohol-fed animals. Treatment of the PLFs with IL-17 and alcohol induced α-SMA expression. Induction of α-SMA and myofibroblast morphology by IL-17 occurred selectively in a Thy-1- fibroblast subpopulation. Chronic alcohol ingestion augmented lung-specific IL-17 expression following bleomycin-induced lung injury. CONCLUSIONS: Alcohol exposure skews T cells toward a Th17 immune response that in turn primes the lung for fibroproliferative disrepair through loss of Thy-1 expression and induction of myofibroblast differentiation. These effects suggest that IL-17 and TGFß1 contribute to fibroproliferative disrepair in the lung and targeting these proteins could limit morbidity and mortality following lung injury in alcoholic individuals.

CD90 highly expressed population harbors a stemness signature and creates an immunosuppressive niche in pancreatic cancer.

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive disease with no effective treatment. Cancer cells, especially cancer stem cells (CSCs), redirect immune cells to evade immune surveillance and even coopt these immune cells to support their growth and metastasis. However, the identification of CSCs and how CSCs interact with immune cells in PDAC remain uncharacterized. Here, we report that CD90 is expressed on both stromal and tumor cells and that high expression of CD90 is related to a poor prognosis in patients with PDAC. The CD90 highly expressed (CD90hi) population in PDAC cells harbors high stemness features and tumorigenicity. Notably, CD90 acts as an anchor for monocyte/macrophage adhesion, providing a physical interaction between CD90hi cells and monocytes/macrophages. In response, the crosstalk between CD90hi cells and monocytes/macrophages promotes immunosuppressive features of immune cells, which enhance the stemness and epithelial-mesenchymal transition (EMT) of PDAC cells. Moreover, PD-L1 is dominantly expressed in the CD90hi population, providing another strategy for these cells to evade immune surveillance. These findings provide an understanding of the biological significance of CD90 expression in PDAC cells and uncover a novel mechanism for how "stem-like" PDAC cells evade immune surveillance.

Thy1 is a positive regulator of osteoblast differentiation and modulates bone homeostasis in obese mice.

Thy1 (CD90), a glycosylated, glycophosphatidylinositol-anchored membrane protein highly expressed by subsets of mesenchymal stem cells and fibroblasts, inhibits adipogenesis. The role of Thy1 on bone structure and function has been poorly studied and represents a major knowledge gap. Therefore, we analyzed the long bones of wild-type (WT) and Thy1 knockout (KO) mice with micro-computed tomography (micro-CT) and histomorphometry to compare changes in bone architecture and overall bone structure. micro-CT analysis of long bones revealed Thy1 KO and WT mice fed a high-fat diet demonstrated bone structural parameters at 4 mo that differed significantly between WT and KO mice. A significant reduction in trabecular bone volume was noted in Thy1 KO mice. The most prominent differences were observed in trabecular bone volume ratio and trabecular bone connectivity density. Consistent with micro-CT measurements, histomorphometric analysis also showed decreased bone volume in the obese Thy1 KO mice compared to obese WT mice. In vitro assays revealed that osteogenic conditions increased Thy1 expression during OB differentiation and absence of Thy1 attenuated osteoblastogenesis. Together, these findings support the concept that Thy1 serves as a major mechanistic link to regulate bone formation and negatively regulate adipogenesis.-Paine, A., Woeller, C. F., Zhang, H., Garcia-Hernandez, M. L., Huertas, N., Xing, L., Phipps, R. P., Ritchlin, C. T. Thy1 is a positive regulator of osteoblast differentiation and modulates bone homeostasis in obese mice.

Beta2-adrenergic signaling affects the phenotype of human cardiac progenitor cells through EMT modulation.

Human cardiac progenitor cells (CPCs) offer great promises to cardiac cell therapy for heart failure. Many in vivo studies have shown their therapeutic benefits, paving the way for clinical translation. The 3D model of cardiospheres (CSs) represents a unique niche-like in vitro microenvironment, which includes CPCs and supporting cells. CSs have been shown to form through a process mediated by epithelial-to-mesenchymal transition (EMT). ß2-Adrenergic signaling significantly affects stem/progenitor cells activation and mobilization in multiple tissues, and crosstalk between ß2-adrenergic signaling and EMT processes has been reported. In the present study, we aimed at investigating the biological response of CSs to ß2-adrenergic stimuli, focusing on EMT modulation in the 3D culture system of CSs. We treated human CSs and CS-derived cells (CDCs) with the ß2-blocker butoxamine (BUT), using either untreated or ß2 agonist (clenbuterol) treated CDCs as control. BUT-treated CS-forming cells displayed increased migration capacity and a significant increase in their CS-forming ability, consistently associated with increased expression of EMT-related genes, such as Snai1. Moreover, long-term BUT-treated CDCs contained a lower percentage of CD90+ cells, and this feature has been previously correlated with higher cardiogenic and therapeutic potential of the CDCs population. In addition, long-term BUT-treated CDCs had an increased ratio of collagen-III/collagen-I gene expression levels, and showed decreased release of inflammatory cytokines, overall supporting a less fibrosis-prone phenotype. In conclusion, ß2 adrenergic receptor block positively affected the stemness vs commitment balance within CSs through the modulation of type1-EMT (so called "developmental"). These results further highlight type-1 EMT to be a key process affecting the features of resident cardiac progenitor cells, and mediating their response to the microenvironment.

Thy1 (CD90) Expression Is Elevated in Radiation-Induced Periprosthetic Capsular Contracture: Implication for Novel Therapeutics.

BACKGROUND: Capsular contracture is a devastating complication of postmastectomy implant-based breast reconstruction. Unfortunately, capsular contracture rates are drastically increased by targeted radiotherapy, a standard postmastectomy treatment. Thy1 (also called CD90) is important in myofibroblast differentiation and scar tissue formation. However, the impact of radiotherapy on Thy1 expression and the role of Thy1 in capsular contracture are unknown. METHODS: The authors analyzed Thy1 expression in primary human capsular tissue and primary fibroblast explants by real-time quantitative polymerase chain reaction, Western blotting, and immunohistochemistry. Thy1 was depleted using RNA interference to determine whether Thy1 expression was essential for the myofibroblast phenotype in capsular fibroblasts. Furthermore, human capsular fibroblasts were treated with a new antiscarring compound, salinomycin, to determine whether Thy1 expression and myofibroblast formation were blocked by salinomycin. RESULTS: In this article, the authors show that radiation therapy significantly increased Thy1 mRNA and protein expression in periimplant scar tissue. Capsular fibroblasts explanted from scar tissue retained the ability to make the myofibroblast-produced scar-forming components collagen I and α-smooth muscle actin. Depletion of Thy1 decreased the fibrotic morphology of capsular fibroblasts and significantly decreased α-smooth muscle actin and collagen levels. Furthermore, the authors show for the first time that salinomycin decreased Thy1 expression and prevented myofibroblast formation in capsular fibroblasts. CONCLUSIONS: These data reveal that ionizing radiation-induced Thy1 overexpression may contribute to increased capsular contracture severity, and fibroblast scar production can be ameliorated through targeting Thy1 expression. Importantly, the authors' new results show promise for the antiscarring ability of salinomycin in radiation-induced capsular contracture. CLINCAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, V.

Thy-1 Regulates VEGF-Mediated Choroidal Endothelial Cell Activation and Migration: Implications in Neovascular Age-Related Macular Degeneration.

PURPOSE: This study addresses the hypothesis that age-related stresses upregulate Thy-1 in choroidal endothelial cells (CECs) and contribute to CEC activation and migration, processes important in choroidal neovascularization (CNV). METHODS: Measurements were made of Thy-1 protein (Western blot) in CECs and Thy-1 mRNA (real time quantitative PCR) in CECs treated with VEGF, CCL11, or PBS or in RPE/choroids from young or old donors or lasered or nonlasered mice. Immunolabeled Thy-1 in ocular sections was compared from young versus old human donor eyes or those with or without neovascular AMD or from lasered versus nonlasered mice. Choroidal endothelial cells transfected with Thy-1 or control siRNA or pretreated with Thy-1 blocking peptide or control were stimulated with VEGF or 7-ketocholesterol (7-KC). Choroidal endothelial cell migration, proliferation, cytoskeletal stress fibers, Rac1 activation, and phosphorylated VEGF receptor 2 (VEGFR2), integrin ß3, and Src were measured. Statistics were performed using ANOVA. RESULTS: Thy-1 was expressed in retinal ganglion cells and in vascular endothelial-cadherin-labeled choroid and localized to human or mouse laser-induced CNV lesions. Thy-1 protein and mRNA were significantly increased in CECs treated with VEGF or CCL11 and in RPE/choroids from aged versus young donor eyes or from lasered mice versus nonlasered controls. Knockdown or inhibition of Thy-1 in CECs significantly reduced VEGF-induced CEC migration and proliferation, stress fiber formation and VEGFR2, Src, integrin ß3 and Rac1 activation, and 7-KC-induced Rac1 and Src activation. CONCLUSIONS: Thy-1 in CECs regulates VEGF-induced CEC activation and migration and links extracellular 7-KC to intracellular signaling. Future studies elucidating Thy-1 mechanisms in neovascular AMD are warranted.

Lipopolysaccharide promotes pulmonary fibrosis in acute respiratory distress syndrome (ARDS) via lincRNA-p21 induced inhibition of Thy-1 expression.

Acute respiratory distress syndrome (ARDS) is a common clinical disorder characterized by pulmonary edema leading to acute lung damage and arterial hypoxemia. Pulmonary fibrosis is a progressive, fibrotic lung disorder, whose pathogenesis in ARDS remains speculative. LincRNA-p21 was a novel regulator of cell proliferation, apoptosis and DNA damage response. This study aims to investigate the effects and mechanism of lincRNA-p21 on pulmonary fibrosis in ARDS. Purified 10 mg/kg LPS was dropped into airways of C57BL/6 mice. Expression levels of lincRNA-p21 and Thy-1 were measured by real-time PCR or western blotting. Proliferation of lung fibroblasts was analyzed by BrdU incorporation assay. Lung and BAL collagen contents were estimated using colorimetric Sircol assay. LincRNA-p21 expression was time-dependently increased and Thy-1 expression was time-dependently reduced in a mouse model of ARDS and in LPS-treated lung fibroblasts. Meanwhile, lung fibroblast proliferation was also time-dependently elevated in LPS-treated lung fibroblasts. In addition, lung fibroblast proliferation could be promoted by lincRNA-p21 overexpression and LPS treatment, however, the elevated lung fibroblast proliferation was further abrogated by Thy-1 overexpression or lincRNA-p21 interference. And Thy-1 interference could elevate cell viability of lung fibroblasts and rescue the reduction of lung fibroblast proliferation induced by lincRNA-p21 interference. Moreover, lincRNA-p21 overexpression dramatically inhibited acetylation of H3 and H4 at the Thy-1 promoter and Thy-1 expression levels in HLF1 cells. Finally, lincRNA-p21 interference rescued LPS-induced increase of lung and BAL collagen contents. LincRNA-p21 could lead to pulmonary fibrosis in ARDS by inhibition of the expression of Thy-1.

Isolation of CD 90+ Fibroblast/Myofibroblasts from Human Frozen Gastrointestinal Specimens.

Fibroblasts/myofibroblasts (MFs) have been gaining increasing attention for their role in pathogenesis and their contributions to both wound healing and promotion of the tumor microenvironment. While there are currently many techniques for the isolation of MFs from gastrointestinal (GI) tissues, this protocol introduces a novel element of isolation of these stromal cells from frozen tissue. Freezing GI tissue specimens not only allows the researcher to acquire samples from worldwide collaborators, biobanks, and commercial vendors, it also permits the delayed processing of fresh samples. The described protocol will consistently yield characteristic spindle-shaped cells with the MF phenotype that express the markers CD90, α-SMA and vimentin. As these cells are derived from patient samples, the use of primary cells also confers the benefit of closely mimicking MFs from disease states-namely cancer and inflammatory bowel diseases. This technique has been validated in gastric, small bowel, and colonic MF primary culture generation. Primary MF cultures can be used in a vast array of experiments over a number of passage and their purity assessed by both immunocytochemistry and flow cytometry analysis.

Characteristics of Multipotent Mesenchymal Stromal Cells Isolated from Human Endometrium.

Cell cultures isolated from human endometrium by enzyme digestion consisted of highly viable fibroblast-like mesenchymal cells expressing CD90, CD73, and CD105. During passage 1, the cultures contained a small fraction of cytokeratin-7(+) epithelial cells that disappeared by passage 2. The cultures from the endometrium could be induced to adipogenic, osteogenic and chondrogenic differentiation in vitro. These findings suggest that human endometrium is a convenient source of biomaterial for minimally invasive isolation of cultures that exhibit typical morphology and immunophenotypic profile of resident multipotent mesenchymal stromal cells retain high viability in vitro.

Blood vessels expressing CD90 in human and rat brain tumors.

Blood vessels in brain tumors, particularly glioblastomas, have been shown to express CD90. CD90(+) cells in and around blood vessels in cancers including brain tumors have been identified as endothelial cells, cancer stem cells, fibroblasts or pericytes. In this study, we aimed to determine the nature or type(s) of cells that express CD90 in human brain tumors as well as an experimental rat glioma model by double immunofluorescence staining. The majority of CD90(+) cells in human glioblastoma tissue expressed CD31, CD34 and von Willebrand factor, suggesting that they were endothelial cells. Vasculatures in a metastatic brain tumor and meningioma also expressed CD90. CD90(+) cells often formed glomeruloid structures, typical of angiogenesis in malignant tumors, not only in glioblastoma but also in metastatic tumors. Some cells in the middle and outer layers of the vasculatures expressed CD90. Similar results were obtained in the rat glioma model. There were cells expressing both α-smooth muscle actin and CD90 in the middle layer of blood vessels, indicating that smooth muscle cells and/or pericytes may express CD90. CD90(+) vasculatures were surrounded by tumor-associated macrophages (TAMs). Thus, in addition to endothelial cells, some other types of cells, such as smooth muscle cells, pericytes and fibroblasts constituting the vasculature walls in brain tumors expressed CD90. Because CD90 has been shown to interact with integrins expressed by circulating monocytes, CD90 might be involved in angiogenesis through recruitment and functional regulation of TAMs in tumors. CD90(+) vasculatures may also interact with tumor cells through interactions with integrins. Because CD90 was not expressed by vasculatures in normal brain tissue, it might be a possible therapeutic target to suppress angiogenesis and tumor growth.

Evidence of CD90+CXCR4+ cells as circulating tumor stem cells in hepatocellular carcinoma.

Primary hepatocellular carcinoma (HCC) often invades into vessels and has a distal metastasis at an early stage, resulting in poor prognosis and therapeutic outcome. The metastasis has been attributable to the dissemination of tumor cells into circulation as circulating tumor cells (CTCs). Moreover, cancer stem cells (CSCs) within CTCs, which are termed as circulating tumor stem cells (CTSCs), are critical for formation of distal metastatic tumors. Although CD133 and CD90 have been used to characterize and isolate CTCs or CSCs in HCC, no good marker (cocktail) has been identified so far for CTSCs in HCC. Here, we show evidence that CD90+CXCR4+ HCC cells may be CTSCs in HCC. CD90+CXCR4+ HCC cells formed tumor spheres in culture and developed tumors after serial adoptive transplantations into NOD/SCID mice, while the CD90-CXCR4-, CD90-CXCR4+ or CD90+CXCR4- cells did not. Moreover, tumor cells were significantly more frequently detected in the circulation when CD90+CXCR4+ HCC cells were subcutaneously transplanted. Further, subcutaneous transplantation of CD90+CXCR4+ HCC cells, but not transplantation of CD90-CXCR4-, CD90-CXCR4+, or CD90+CXCR4- cells significantly developed distal metastatic tumors. Together, these data suggest that CD90+CXCR4+ HCC cells may be CTSCs and selective elimination of these cells may substantially improve the current HCC therapy by reducing cancer metastasis.

The novel Rho kinase (ROCK) inhibitor K-115: a new candidate drug for neuroprotective treatment in glaucoma.

PURPOSE: To investigate the effect of K-115, a novel Rho kinase (ROCK) inhibitor, on retinal ganglion cell (RGC) survival in an optic nerve crush (NC) model. Additionally, to determine the details of the mechanism of K-115's neuroprotective effect in vivo and in vitro. METHODS: ROCK inhibitors, including K-115 and fasudil (1 mg/kg/d), or vehicle were administered orally to C57BL/6 mice. Retinal ganglion cell death was then induced with NC. Retinal ganglion cell survival was evaluated by counting surviving retrogradely labeled cells and measuring RGC marker expression with quantitative real-time polymerase chain reaction (qRT-PCR). Total oxidized lipid levels were assessed with a thiobarbituric acid-reactive substances (TBARS) assay. Reactive oxygen species (ROS) levels were assessed by co-labeling with CellROX and Fluorogold. Expression of the NADPH oxidase (Nox) family of genes was evaluated with qRT-PCR. RESULTS: The survival of RGCs after NC was increased 34 ± 3% with K-115, a significantly protective effect. Moreover, a similar effect was revealed by the qRT-PCR analysis of Thy-1.2 and Brn3a, RGC markers. Levels of oxidized lipids and ROS also increased with time after NC. NC-induced oxidative stress, including oxidation of lipids and production of ROS, was significantly attenuated by K-115. Furthermore, expression of the Nox gene family, especially Nox1, which is involved in the NC-induced ROS production pathway, was dramatically reduced by K-115. CONCLUSIONS: The results indicated that oral K-115 administration delayed RGC death. Although K-115 may be mediated through Nox1 downregulation, we found that it did not suppress ROS production directly. Our findings show that K-115 has a potential use in neuroprotective treatment for glaucoma and other neurodegenerative diseases.

High-resolution molecular validation of self-renewal and spontaneous differentiation in clinical-grade adipose-tissue derived human mesenchymal stem cells.

Improving the effectiveness of adipose-tissue derived human mesenchymal stromal/stem cells (AMSCs) for skeletal therapies requires a detailed characterization of mechanisms supporting cell proliferation and multi-potency. We investigated the molecular phenotype of AMSCs that were either actively proliferating in platelet lysate or in a basal non-proliferative state. Flow cytometry combined with high-throughput RNA sequencing (RNASeq) and RT-qPCR analyses validate that AMSCs express classic mesenchymal cell surface markers (e.g., CD44, CD73/NT5E, CD90/THY1, and CD105/ENG). Expression of CD90 is selectively elevated at confluence. Self-renewing AMSCs express a standard cell cycle program that successively mediates DNA replication, chromatin packaging, cyto-architectural enlargement, and mitotic division. Confluent AMSCs preferentially express genes involved in extracellular matrix (ECM) formation and cellular communication. For example, cell cycle-related biomarkers (e.g., cyclins E2 and B2, transcription factor E2F1) and histone-related genes (e.g., H4, HINFP, NPAT) are elevated in proliferating AMSCs, while ECM genes are strongly upregulated (>10-fold) in quiescent AMSCs. AMSCs also express pluripotency genes (e.g., POU5F1, NANOG, KLF4) and early mesenchymal markers (e.g., NES, ACTA2) consistent with their multipotent phenotype. Strikingly, AMSCs modulate expression of WNT signaling components and switch production of WNT ligands (from WNT5A/WNT5B/WNT7B to WNT2/WNT2B), while upregulating WNT-related genes (WISP2, SFRP2, and SFRP4). Furthermore, post-proliferative AMSCs spontaneously express fibroblastic, osteogenic, chondrogenic, and adipogenic biomarkers when maintained in confluent cultures. Our findings validate the biological properties of self-renewing and multi-potent AMSCs by providing high-resolution quality control data that support their clinical versatility.

Expression of CD90, CD96, CD117, and CD123 on different hematopoietic cell populations from pediatric patients with acute myeloid leukemia.

BACKGROUND AND AIMS: In trying to contribute to our knowledge on the biology of hematopoietic stem cells (HSC) and hematopoietic progenitor cells (HPC) from pediatric acute myeloid leukemia (AML), in the present study we analyzed the expression of four cell surface antigens relevant to human hematopoiesis-CD90, CD96, CD117, and CD123-in bone marrow from pediatric AML patients and normal control subjects. METHODS: CD34(+) CD38(-) cells (enriched for HSC) and CD34(+) CD38(+) cells (enriched for HPC) were resolved on the basis of CD34 and CD38 expression. Concomitantly, expression of CD90 and CD96 or CD117 and CD123 was assessed by multicolor flow cytometry in each cell population. RESULTS: CD90 and CD117 were expressed in a low proportion of CD34(+) CD38(-) and CD34(+) CD38(+) cells and no significant differences were observed between normal marrow and AML at diagnosis. In contrast, CD96(+) cells and CD123(+) cells were found at significantly higher levels in both cell populations from AML at diagnosis, as compared to normal marrow. Levels of both cell surface markers after treatment remained higher than in normal marrow. DISCUSSION: These results show an increased frequency of CD96(+) and CD123(+) cells within the CD34(+) cell population from pediatric AML; this is consistent with the findings reported previously for adult AML. Our study supports the notion that expression of such antigens should be explored for their use as markers for diagnosis and prognosis.

Investigation of diagnostic utility and expression profiles of stem cell markers (CD133 and CD90) in hepatocellular carcinoma, small cell dysplasia, and cirrhosis.

The aim of this study was to investigate the expression rates of CD133 and CD90 in cirrhosis-dysplastic nodule-HCC (Crh-DN-HCC) sequence related to the etiologic background. Thirty-five HCC, 8 small cell dysplasia (SCD), and 63 cases of cirrhosis having different etiologies were collected. Immunohistochemical expressions of CD133 and CD90 were evaluated. CD133 positivity was higher in HCC cases with chronic hepatitis B and CD90 with chronic hepatitis C. The highest staining rate was seen in poorly differentiated HCC cases. Only one SCD case and almost half of the cirrhotic cases which were stained for CD133 were associated with hepatitis B; none was stained for CD90. Increased CD133 expression indicated a significantly shorter overall survival rate. No significant relationship was detected between the expression rates of CD133 or CD90 and other parameters. In this study, which investigates the immunohistochemical expression profiles of CD133 and CD90 through Crh-DN-HCC sequence, the highest staining rate was detected in HCC. It is rational to try to elucidate the earliest events in hepatocarcinogenesis by studying SCD. It is important to be aware of this issue in daily practice, which will provide a deeper insight into the understanding of the effects of CSCs in the progression and management of HCC.

Rat cortex and hippocampus-derived soluble factors for the induction of adipose-derived mesenchymal stem cells into neuron-like cells.

To simulate brain microenvironment, adipose-derived mesenchymal stem cells (AMSC) were induced to differentiate to neuronal-like cells in rat cortex and hippocampus medium (Cox + Hip). First, isolated AMSC were characterized by flow cytometer and the capacity of adipogenesis and osteogenesis. After induction in rat cortex and hippocampus conditioned medium, the cell morphological change was examined and neural marker proteins (ß-Ш-Tubulin, NSE, Nissl body) expression was detected by immunofluorescence staining. A variety of synaptic marker proteins, including GAP43, SHANK2, SHANK3 and Bassoon body, were detected. ELISA was used to measure brain derived neurotrophic factor (BDNF) and nerve growth factor (NGF) secretion at different time-points. AMSCs positively expressed CD13, CD44 and CD90 and could differentiate into osteoblasts or adipocytes. After induction in Cox + Hip medium for 14 days, cells had a typical neuronal perikaryal appearance, which was suggestive of neuronal differentiation. After 14 days of Cox + Hip treatment, the percentage of cells expressing ß-Ⅲ-Tubulin, NSE and Nissl was 53.9 ± 0.8%, 51.3 ± 1.7% and 16.4 ± 2.1%, respectively. Expression of GAP43, SHANK2, SHANK3 and Bassoon body was detected, indicating synapse formation after treatment in Cox + Hip medium. Differentiated AMSCs secreted neurotrophic factors NGF and BDNF. Thus rat cortex and hippocampus-derived soluble factors can induce AMSCs to a neuronal-like phenotype, suggesting that AMSCs have a dual role in supplementing newborn neurons and secreting neurotrophic factors, and therefore could be help as a potential treatment for nervous system diseases.

Immunophenotypic characterization and tenogenic differentiation of mesenchymal stromal cells isolated from equine umbilical cord blood.

Mesenchymal stem cells (MSCs) isolated from umbilical cord blood (UCB) in equines have not been well characterized with respect to the expression of pluripotency and mesenchymal markers and for tenogenic differentiation potential in vitro. The plastic adherent fibroblast-like cells isolated from 13 out of 20 UCB samples could proliferate till passage 20. The cells expressed pluripotency markers (OCT4, NANOG, and SOX2) and MSC surface markers (CD90, CD73, and CD105) by RT-PCR, but did not express CD34, CD45, and CD14. On immunocytochemistry, the isolated cells showed expression of CD90 and CD73 proteins, but tested negative for CD34 and CD45. In flow cytometry, CD29, CD44, CD73, and CD90 were expressed by 96.36 ± 1.28%, 93.40 ± 0.70%, 73.23 ± 1.29% and 46.75 ± 3.95% cells, respectively. The UCB-MSCs could be differentiated to tenocytes by culturing in growth medium supplemented with 50 ng/ml of BMP-12 by day 10. The differentiated cells showed the expression of mohawk homeobox (Mkx), collagen type I alpha 1 (Col1α1), scleraxis (Scx), tenomodulin (Tnmd) and decorin (Dcn) by RT-PCR. In addition, flow cytometry detected tenomodulin and decorin protein in 95.65 ± 2.15% and 96.30 ± 1.00% of differentiated cells in comparison to 11.30 ± 0.10% and 19.45 ± 0.55% cells, respect vely in undifferentiated control cells. The findings support the observation that these cells may be suitable for therapeutic applications, including ruptured tendons in racehorses.

Surface design of antibody-immobilized thermoresponsive cell culture dishes for recovering intact cells by low-temperature treatment.

Antibody-immobilized thermoresponsive poly(N-isopropylacrylamide-co-2-carboxyisopropylacrylamide) [poly(IPAAm-co-CIPAAm)]-grafted cell culture surfaces were designed to enhance both the initial adhesion of weakly adhering cells and the ability of cells to detach in response to low temperature through the regulation of affinity binding between immobilized antibodies and antigens on the cellular surface. Ty-82 cells and neonatal normal human dermal fibroblasts (NHDFs), which express CD90 on the cell surface, adhered to anti-CD90 antibody-immobilized thermoresponsive surfaces at 37°C, a condition at which the grafted thermoresponsive polymer chains shrank. Adherent Ty-82 cells were detached from the surfaces by lowering the temperature to 20°C and applying external forces, such as pipetting, whereas cultured NHDF sheets spontaneously detached themselves from the surface in response to reduced temperature alone. When the temperature was decreased to 20°C, the swelling of grafted thermoresponsive polymer chains weakened the affinity binding between immobilized antibody and antigen on the cells due to the increasing steric hindrance of the polymer chains around the antigen-recognition site of the immobilized antibodies. No contamination was detected on cells harvested from covalently immobilized antibodies on the culture surfaces by low-temperature treatment, whereas a carryover of the antibody and avidin from the avidin-biotin binding surface was observed. Furthermore, the initial adhesion of adipose tissue-derived cells, which adhere weakly to PIPAAm-grafted surfaces, was enhanced on the antibody-immobilized thermoresponsive surfaces.