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Hematopoietic Cell Lines (hematopoietic + cell_line)
Selected AbstractsFragmin/Protamine Microparticle-Coated Matrix Immobilized Cytokines to Stimulate Various Cell Proliferations With Low Serum MediaARTIFICIAL ORGANS, Issue 6 2009Satoko Kishimoto Abstract:, Fragmin/protamine microparticles (F/P MPs) have been shown to bind to culture plates, thereby retaining heparin-binding cytokines. Most protocols for in vitro cultures of human microvascular endothelial cells (hMVECs), human dermal fibroblast cells (hDFCs), and hematopoietic cell line (TF-1) include high fetal bovine serum (FBS) (10%) medium as a nutritional supplement. Growth rates of those cells on the F/P MP-coated plates were higher in low FBS (1%) medium containing fibroblast growth factor (FGF)-2 (for hMVECs and hDFCs) and interleukin (IL)-3/granulocyte-macrophage colony-stimulating factor (for TF-1 cells) than without coating. The cytokines in low FBS medium were shown to be immobilized on the F/P MP-coated plate and released into the culture medium with a half releasing time of 4,5 days. Furthermore, those cells grew well on each cytokine-preimmobilized F/P MP-coated plate in low FBS medium. Thus, the F/P MP-coated matrix with adequate heparin-binding cytokines may provide biomaterials for controlling cellular growth and differentiation. [source] ADAM17 activity during human neutrophil activation and apoptosisEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 4 2006Bruce Walcheck Dr. Abstract Substrates of the metalloprotease ADAM17 (also known as TNF-, converting enzyme or TACE) undergo ectodomain shedding and include various inflammatory modulators. Though polymorphonuclear leukocytes contribute significantly to inflammation, direct analyses of ADAM17 on human neutrophils are very limited. In addition, the current understanding of the processes regulating ADAM17 activity primarily relate to its rapid activation. Therefore, to extend insights into the mechanisms of ADAM17 activity, we examined its surface expression and the shedding of its substrates during extended periods of neutrophil activation and apoptosis. Contrary to studies with immortalized hematopoietic cell lines, we report that surface expression of ADAM17 is maintained by human neutrophils activated with formyl peptides or by FcR/complement receptor-mediated phagocytosis. Interestingly, bacterial phagocytosis resulted in a significant increase in ADAM17 expression several hours after pathogen engulfment. We provide novel evidence that ADAM17 surface expression is also maintained during spontaneous and anti-Fas-induced neutrophil apoptosis. The well-validated ADAM17 substrates L-selectin and proTNF-, were shed efficiently by neutrophils under each of the conditions tested. Our data thus indicate prolonged ADAM17 expression during neutrophil effector functions. The implications of this may be a role by ADAM17 in both the induction and down-regulation of neutrophil activity. [source] Osteoclastogenesis-Related Antigen, a Novel Molecule on Mouse Stromal Cells, Regulates Osteoclastogenesis,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 4 2003Satoshi Arai Abstract Osteoclastogenesis is regulated by RANKL expressed on stromal cells. In this study, we sought to isolate a new surface molecule regulating osteoclastogenesis on stromal cells by generating monoclonal antibodies. A rat was immunized with the mouse stromal cell line, TSB13, which can support osteoclastogenesis, and a monoclonal antibody, A15-1, was obtained. A15-1 bound to a surface antigen on TSB13 cells, termed osteoclastogenesis-related antigen (OCRA), and immunoprecipitation with this antibody revealed that OCRA was a 220-kDa molecule. By means of flow cytometry, the A15-1 antigen (OCRA) was found to be expressed on various mesenchymal cell lines but not on hematopoietic cell lines, and the expression level of OCRA on the TSB13 cells was slightly increased by treatment with 1,,25(OH)2D3. When osteoclast progenitors and TSB13 cells were co-cultured in the presence of 1,,25(OH)2D3, the addition of A15-1 inhibited osteoclast differentiation in a dose-dependent manner; however, no significant inhibition of soluble RANKL-induced osteoclastogenesis was observed, suggesting that A15-1 inhibited only stromal cell-dependent osteoclastogenesis. The same inhibitory effect of A15-1 was also observed when primary bone marrow-derived stromal cells were used. The osteoclastogenesis-promoting effects of other osteotropic factors, such as parathyroid hormone (PTH) and interleukin (IL)-1,, were also inhibited by A15-1. Time-course analysis of osteoclast differentiation in vitro indicated that the initial 2 days of treatment with A15-1 was sufficient for inhibition, suggesting that A15-1 inhibits the early stages of osteoclast differentiation. Finally, we investigated the in vivo effects of A15-1 on PTH-induced hypercalcemia in mice. Treatment with A15-1 significantly decreased the osteoclast surface in the PTH-administered mice. Taken together, our data indicate that OCRA, a novel A15-1-detected antigen, regulates stromal cell-dependent osteoclastogenesis. [source] Collagen promotes sustained glycoprotein VI signaling in platelets and cell linesJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 11 2007M. G. TOMLINSON Summary. Background:,Glycoprotein (GP)VI is the major signaling receptor for collagen on platelets and signals via the associated FcR,-chain, which has an immunoreceptor tyrosine-containing activation motif (ITAM). Objective:,To determine why GPVI,FcR, signals poorly, or not at all, in response to collagen in hematopoietic cell lines, despite robust responses to the GPVI-reactive snake venom toxin convulxin. Methods and results:,Using a nuclear factor of activated T-cells (NFAT) transcriptional reporter assay, a sensitive readout for sustained ITAM signaling, we demonstrate collagen-induced GPVI,FcR, signaling in hematopoietic cell lines. This is accompanied by relatively weak but sustained protein tyrosine phosphorylation, in contrast to the stronger but transient response to convulxin. Sustained signaling by collagen is also observed in platelets and is necessary for the maintenance of spreading on collagen. Finally, in cell lines, the inhibitory collagen receptor leukocyte-associated immunoglobulin-like receptor-1 (LAIR-1), which is not expressed on platelets but is present on most hematopoietic cells, inhibits GPVI responses to collagen but not convulxin. Conclusion:,The inability of previous studies to readily detect GPVI collagen signaling in cell lines is probably because of the weak but sustained nature of the signal and the presence of the inhibitory collagen receptor LAIR-1. In platelets, we propose that GPVI,FcR, has evolved to transmit sustained signals in order to maintain spreading over several hours, as well as facilitating rapid activation through release of feedback agonists and integrin activation. The establishment of a cell line NFAT assay will facilitate the molecular dissection of GPVI signaling and the identification of GPVI antagonists in drug discovery. [source] Gene therapy for HIV/AIDS: the potential for a new therapeutic regimenTHE JOURNAL OF GENE MEDICINE, Issue 8 2003Greg Fanning Abstract Human Immunodeficiency Virus (HIV) is the etiologic agent of Acquired Immunodeficiency Syndrome (AIDS). HIV/AIDS is a disease that, compared with the not so distant past, is now better held in check by current antiretroviral drugs. However, it remains a disease not solved. Highly active antiretroviral therapy (HAART) generally uses two non-nucleoside and one nucleoside reverse transcriptase (RT) inhibitor or two non-nucleoside RT and one protease inhibitor. HAART is far more effective than the mono- or duo-therapy of the past, which used compounds like the nucleoside reverse transcriptase inhibitor AZT or two nucleoside reverse transcriptase inhibitors. However, even with the relatively potent drug cocktails that comprise HAART, there are the issues of (i) HIV escape mutants, (ii) an apparent need to take the drugs in an ongoing manner, and (iii) the drugs' side effects that are often severe. This review speaks to the potential addition to these potent regimens of another regimen, namely the genetic modification of target hematopoietic cells. Such a new treatment paradigm is conceptually attractive as it may yield the constant intracellular expression of an anti-HIV gene that acts to inhibit HIV replication and pathogenicity. A body of preclinical work exists showing the inhibition of HIV replication and decreased HIV pathogenicity by anti-HIV genetic agents. This preclinical work used hematopoietic cell lines and primary cells as the target tissue. More recently, several clinical trials have sought to test this concept in vivo. Copyright © 2003 John Wiley & Sons, Ltd. [source] | ||||||||||