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  • Two cell circuits of oriented adult hippocampal neurons on self-assembled monolayers for use in the study of neuronal communication in a defined system. 23611164

    In this study, we demonstrate the directed formation of small circuits of electrically active, synaptically connected neurons derived from the hippocampus of adult rats through the use of engineered chemically modified culture surfaces that orient the polarity of the neuronal processes. Although synaptogenesis, synaptic communication, synaptic plasticity, and brain disease pathophysiology can be studied using brain slice or dissociated embryonic neuronal culture systems, the complex elements found in neuronal synapses makes specific studies difficult in these random cultures. The study of synaptic transmission in mature adult neurons and factors affecting synaptic transmission are generally studied in organotypic cultures, in brain slices, or in vivo. However, engineered neuronal networks would allow these studies to be performed instead on simple functional neuronal circuits derived from adult brain tissue. Photolithographic patterned self-assembled monolayers (SAMs) were used to create the two-cell "bidirectional polarity" circuit patterns. This pattern consisted of a cell permissive SAM, N-1[3-(trimethoxysilyl)propyl] diethylenetriamine (DETA), and was composed of two 25 μm somal adhesion sites connected with 5 μm lines acting as surface cues for guided axonal and dendritic regeneration. Surrounding the DETA pattern was a background of a non-cell-permissive poly(ethylene glycol) (PEG) SAM. Adult hippocampal neurons were first cultured on coverslips coated with DETA monolayers and were later passaged onto the PEG-DETA bidirectional polarity patterns in serum-free medium. These neurons followed surface cues, attaching and regenerating only along the DETA substrate to form small engineered neuronal circuits. These circuits were stable for more than 21 days in vitro (DIV), during which synaptic connectivity was evaluated using basic electrophysiological methods.
    Document Type:
    Reference
    Product Catalog Number:
    Multiple
    Product Catalog Name:
    Multiple
  • Dosage and cell line dependent inhibitory effect of bFGF supplement in human pluripotent stem cell culture on inactivated human mesenchymal stem cells. 24465853

    Many different culture systems have been developed for expanding human pluripotent stem cells (hESCs and hiPSCs). In general, 4-10 ng/ml of bFGF is supplemented in culture media in feeder-dependent systems regardless of feeder cell types, whereas in feeder-free systems, up to 100 ng/ml of bFGF is required for maintaining long-term culture on various substrates. The amount of bFGF required in native hESCs growth niche is unclear. Here we report using inactivated adipose-derived human mesenchymal stem cells as feeder cells to examine long-term parallel cultures of two hESCs lines (H1 and H9) and one hiPSCs line (DF19-9-7T) in media supplemented with 0, 0.4 or 4 ng/ml of bFGF for up to 23 passages, as well as parallel cultures of H9 and DF19 in media supplemented with 4, 20 or 100 ng/ml bFGF for up to 13 passages for comparison. Across all cell lines tested, bFGF supplement demonstrated inhibitory effect over growth expansion, single cell colonization and recovery from freezing in a dosage dependent manner. In addition, bFGF exerted differential effects on different cell lines, inducing H1 and DF19 differentiation at 4 ng/ml or higher, while permitting long-term culture of H9 at the same concentrations with no apparent dosage effect. Pluripotency was confirmed for all cell lines cultured in 0, 0.4 or 4 ng/ml bFGF excluding H1-4 ng, as well as H9 cultured in 4, 20 and 100 ng/ml bFGF. However, DF19 demonstrated similar karyotypic abnormality in both 0 and 4 ng/ml bFGF media while H1 and H9 were karyotypically normal in 0 ng/ml bFGF after long-term culture. Our results indicate that exogenous bFGF exerts dosage and cell line dependent effect on human pluripotent stem cells cultured on mesenchymal stem cells, and implies optimal use of bFGF in hESCs/hiPSCs culture should be based on specific cell line and its culture system.
    Document Type:
    Reference
    Product Catalog Number:
    MAB4304
    Product Catalog Name:
    Anti-Stage-Specific Embryonic Antigen-4 Antibody, clone MC-813-70
  • Control of neural cell composition in poly(ethylene glycol) hydrogel culture with soluble factors. 21823990

    Poly(ethylene glycol) (PEG) hydrogels are being developed as cell delivery vehicles that have great potential to improve neuronal replacement therapies. Current research priorities include (1) characterizing neural cell growth within PEG hydrogels relative to standard culture systems and (2) generating neuronal-enriched populations within the PEG hydrogel environment. This study compares the percentage of neural precursor cells (NPCs), neurons, and glia present when dissociated neural cells are seeded within PEG hydrogels relative to standard monolayer culture. Results demonstrate that PEG hydrogels enriched the initial cell population for NPCs, which subsequently gave rise to neurons, then to glia. Relative to monolayer culture, PEG hydrogels maintained an increased percentage of NPCs and a decreased percentage of glia. This neurogenic advantage of PEG hydrogels is accentuated in the presence of basic fibroblast growth factor and epidermal growth factor, which more potently increase NPC and neuronal expression markers when applied to cells cultured within PEG hydrogels. Finally, this work demonstrates that glial differentiation can be selectively eliminated upon supplementation with a γ-secretase inhibitor. Together, this study furthers our understanding of how the PEG hydrogel environment influences neural cell composition and also describes select soluble factors that are useful in generating neuronal-enriched populations within the PEG hydrogel environment.
    Document Type:
    Reference
    Product Catalog Number:
    Multiple
    Product Catalog Name:
    Multiple
  • Functional neural stem cell isolation from brains of adult mutant SOD1 (SOD1(G93A)) transgenic amyotrophic lateral sclerosis (ALS) mice. 20810028

    OBJECTIVES: The aim of present study is to investigate more functional neural stem cells (NSCs) could be isolated from brains with amyotrophic lateral sclerosis (ALS) and expanded in vitro, based on previous reports demonstrating de novo neurogenesis is enhanced to replace degenerating neural tissue.METHODS: Thirteen- or eighteen-week-old mutant human Cu/Zn superoxide dismutase (SOD1(G93A)) transgenic ALS and wild-type SOD1 transgenic control mice were utilized. Changes in numbers of NSCs in the dentate gyrus were analyzed by immunohistochemistry against nestin and CD133. NSCs were primarily cultured from hippocampus of ALS or control mice. Expression of NSC markers, in vitro expansion capacity, and differentiating potential were compared.RESULTS: Hippocampus of 13-week-old pre-symptomatic ALS mice harbor more cells that can be propagated for more than 12 passages in vitro, compared with same age control mice. Primarily-cultured cells formed neurospheres in the NSC culture medium, expressed NSC markers, and differentiated into cells with differentiated neural cell characteristics in the differentiation condition confirming that they are NSCs. In contrast, long-term expansible NSCs could not be derived from brains of 18-week-old symptomatic ALS mice with the same experimental techniques, although they had comparable nestin-immunoreactive cells in the dentate gyrus.DISCUSSION: These results would suggest that increased neuroregeneration in early phase of ALS could be translated to regenerative approaches; however, long-term exposure to ALS microenvironments could abolish functional capacities of NSCs.
    Document Type:
    Reference
    Product Catalog Number:
    Multiple
    Product Catalog Name:
    Multiple
  • Cholera toxin regulates a signaling pathway critical for the expansion of neural stem cell cultures from the fetal and adult rodent brains. 20520777

    New mechanisms that regulate neural stem cell (NSC) expansion will contribute to improved assay systems and the emerging regenerative approach that targets endogenous stem cells. Expanding knowledge on the control of stem cell self renewal will also lead to new approaches for targeting the stem cell population of cancers.Here we show that Cholera toxin regulates two recently characterized NSC markers, the Tie2 receptor and the transcription factor Hes3, and promotes the expansion of NSCs in culture. Cholera toxin increases immunoreactivity for the Tie2 receptor and rapidly induces the nuclear localization of Hes3. This is followed by powerful cultured NSC expansion and induction of proliferation both in the presence and absence of mitogen.Our data suggest a new cell biological mechanism that regulates the self renewal and differentiation properties of stem cells, providing a new logic to manipulate NSCs in the context of regenerative disease and cancer.
    Document Type:
    Reference
    Product Catalog Number:
    Multiple
    Product Catalog Name:
    Multiple
  • Fabrication of a cell-adhesive protein imprinting surface with an artificial cell membrane structure for cell capturing. 19443203

    We proposed a new molecular imprinting procedure based on molecular integration for the purpose of cell capture. We selected the cell-adhesive protein fibronectin (FN) as the imprinting protein for preparing templates and evaluated selective cell adhesion on the FN imprinting substrate. Silica beads with a diameter of 15 microm were used as the stamp matrix and FN molecules were adsorbed as a monolayer. The FN recognition sites were constructed by integrating a surfactant as the ligand and immobilizing it with new biocompatible photoreactive phospholipid polymer composed of 2-methacryloyloxyethyl phosphorylcholine (MPC) units. As control substrates, imprinting procedures were carried out using albumin (BSA imprinting substrate) and without imprinting protein (non-imprinting substrate). The binding of FN from the cell culture medium with the fetal calf serum was achieved on the FN imprinting substrate, and induced the cell adhesion. On the other hand, on the non-imprinted and BSA imprinting substrates, the FN scarcely bound from the cell culture medium, and subsequent cell adhesion could not be observed on the substrate. These results indicate that the FN binding sites were well constructed by arranging the ligand surfactant to a suitable position and immobilized by the photoreactive MPC polymer. The MPC polymer prevented the nonspecific adsorption of proteins from the cell culture medium. We concluded that this procedure is convenient and can be potentially used for the preparation of surfaces for cell engineering devices.
    Document Type:
    Reference
    Product Catalog Number:
    AB2047
    Product Catalog Name:
    Anti-Fibronectin Antibody
  • Intercellular transfer of proteins as identified by stable isotope labeling of amino acids in cell culture. 20026604

    We tracked the extracellular fate of proteins of pulmonary origin using the technique of stable isotope labeling of amino acids in cell culture (SILAC) in cell-impermeable Transwell culture systems. We find that irradiation to murine lung and lung-derived cells induces their release of proteins that are capable of entering neighboring cells, including primary murine bone marrow cells as well as prostate cancer and hematopoietic cell lines. The functional classification of transferred proteins was broad and included transcription factors, mediators of basic cellular processes and components of the nucleosome remodeling and deacetylase complex, including metastasis associated protein 3 and retinoblastoma-binding protein 7. In further analysis we find that retinoblastoma-binding protein 7 is a transcriptional activator of E-cadherin and that its intercellular transfer leads to decreased gene expression of downstream targets such as N-cadherin and vimentin. SILAC-generated data sets offer a valuable tool to identify and validate potential paracrine networks that may impact relevant biologic processes associated with phenotypic and genotypic signatures of health and disease.
    Document Type:
    Reference
    Product Catalog Number:
    17-371
    Product Catalog Name:
    EZ-ChIP™
  • Colorectal cancer desmoplastic reaction up-regulates collagen synthesis and restricts cancer cell invasion. 21987222

    During cancer cell growth many tumors exhibit various grades of desmoplasia, unorganized production of fibrous or connective tissue, composed mainly of collagen fibers and myofibroblasts. The accumulation of an extracellular matrix (ECM) surrounding tumors directly affects cancer cell proliferation, migration and spread; therefore the study of desmoplasia is of vital importance. Stromal fibroblasts surrounding tumors are activated to myofibroblasts and become the primary producers of ECM during desmoplasia. The composition, density and organization of this ECM accumulation play a major role on the influence desmoplasia has upon tumor cells. In this study, we analyzed desmoplasia in vivo in human colorectal carcinoma tissue, detecting an up-regulation of collagen I, collagen IV and collagen V in human colorectal cancer desmoplastic reaction. These components were then analyzed in vitro co-cultivating colorectal cancer cells (Caco-2 and HCT116) and fibroblasts utilizing various co-culture techniques. Our findings demonstrate that direct cell-cell contact between fibroblasts and colorectal cancer cells evokes an increase in ECM density, composed of unorganized collagens (I, III, IV and V) and proteoglycans (biglycan, fibromodulin, perlecan and versican). The desmoplastic collagen fibers were thick, with an altered orientation, as well as deposited as bundles. This increased ECM density inhibited the migration and invasion of the colorectal tumor cells in both 2D and 3D co-culture systems. Therefore this study sheds light on a possible restricting role desmoplasia could play in colorectal cancer invasion.
    Document Type:
    Reference
    Product Catalog Number:
    AB763P
    Product Catalog Name:
    Anti-Collagen Type V Antibody
  • Chemerin, a novel peroxisome proliferator-activated receptor gamma (PPARgamma) target gene that promotes mesenchymal stem cell adipogenesis. 21572083

    Chemerin is an adipocyte-secreted protein that regulates adipogenesis and the metabolic function of mature adipocytes via activation of chemokine-like receptor 1 (CMKLR1). Herein we report the interaction of peroxisome proliferator-activated receptor γ (PPARγ) and chemerin in the context of adipogenesis. Knockdown of chemerin or CMKLR1 expression or antibody neutralization of secreted chemerin protein arrested adipogenic clonal expansion of bone marrow mesenchymal stem cells (BMSCs) by inducing a loss of G(2)/M cyclins (cyclin A2/B2) but not the G(1)/S cyclin D2. Forced expression of PPARγ in BMSCs did not completely rescue this loss of clonal expansion and adipogenesis following chemerin or CMKLR1 knockdown. However, forced expression and/or activation of PPARγ in BMSCs as well as non-adipogenic cell types such as NIH-3T3 embryonic fibroblasts and MCA38 colon carcinoma cells significantly induced chemerin expression and secretion. Sequence analysis revealed a putative PPARγ response element (PPRE) sequence within the chemerin promoter. This PPRE was able to confer PPARγ responsiveness on a heterologous promoter, and mutation of this sequence abolished activation of the chemerin promoter by PPARγ. Chromatin immunoprecipitation confirmed the direct association of PPARγ with this PPRE. Treatment of mice with rosiglitazone elevated chemerin mRNA levels in adipose tissue and bone marrow coincident with an increase in circulating chemerin levels. Together, these findings support a fundamental role for chemerin/CMKLR1 signaling in clonal expansion during adipocyte differentiation as well as a role for PPARγ in regulating chemerin expression.
    Document Type:
    Reference
    Product Catalog Number:
    MAB3604