Two Signaling Pathways Can Increase Fas Expression in Human Thymocytes
1998; Elsevier BV; Volume: 92; Issue: 4 Linguagem: Inglês
10.1182/blood.v92.4.1297
ISSN1528-0020
AutoresNathalie Moulian, Jocelyne Bidault, C Planché, Sonia Berrih‐Aknin,
Tópico(s)Natural Compounds in Disease Treatment
ResumoAbstract Fas, a cell surface receptor, can induce apoptosis after cross-linking with its ligand. Fewer than 3% of human thymocytes strongly express Fas. We report that Fas antigen expression can be upregulated by two signaling pathways in vitro, one mediated by anti-CD3 and the other by interleukin-7 + interferon-γ. The two signaling pathways differed in several respects. (1) Fas expression increased in all thymic subsets after cytokine activation, but only in the CD4 lineage after anti-CD3 activation. (2) Fas upregulation was inhibited by cyclosporin A (a calcineurin inhibitor) in anti-CD3–activated but not in cytokine-activated thymocytes. (3) Cycloheximide (a metabolic inhibitor) inhibited Fas upregulation in cytokine-activated thymocytes but not in anti-CD3–activated thymocytes. (4) Cytokine-activated thymocytes were more susceptible than anti-CD3–activated thymocytes to Fas-induced apoptosis, a difference mainly accounted for by CD4+ cells. The nature of the stimulus might thus influence the susceptibility of human thymocytes to Fas-induced apoptosis. © 1998 by The American Society of Hematology.
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