| Autor: |
Chen J; Department of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University, Richmond 23298, USA., Jacobs-Helber SM, Barber DL, Sawyer ST |
| Jazyk: |
angličtina |
| Zdroj: |
Experimental cell research [Exp Cell Res] 2004 Aug 01; Vol. 298 (1), pp. 155-66. |
| DOI: |
10.1016/j.yexcr.2004.04.009 |
| Abstrakt: |
Primary erythroid cells and erythroid cell lines may synthesize and secrete tumor necrosis factor-alpha (TNF-alpha) following stimulation with erythropoietin (EPO). The effect of triggering TNF-alpha synthesis and secretion was investigated in erythroleukemia and myeloid cell lines: HCD57, DA3-EPOR, and BAF3-EPOR. The EPO-induced, membrane-bound form of autocrine TNF-alpha seemed to enhance proliferation of HCD57 and DA3-EPOR cells; however, the concentration of secreted autocrine/paracrine TNF-alpha was never sufficient to have an effect. Autocrine TNF-alpha acts through TNFRII receptors to stimulate proliferation. Modulation of mitogen-activated protein kinase (MAPK)/extracellular signal-related kinase (ERK-1/2) activity by the membrane-bound form of autocrine TNF-alpha apparently played a central role in the control of EPO-dependent proliferation of HCD57 and DA3-EPOR cells. Primary erythroid cells and DA3-EPOR cells were found to express similar, high levels of both TNFRI and TNFRII, showing that differential expression of TNF-alpha receptors does not explain why primary cells are inhibited and DA3-EPOR cells are stimulated by autocrine TNF-alpha. BAF3 cells expressing a mutant EPOR with no cytoplasmic tyrosine residues were capable of triggering EPO-dependent TNF-alpha synthesis and secretion, indicating that tyrosine-docking sites in the EPOR were not required for EPO-dependent TNF-alpha secretion. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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