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  • Beryllium-induced TNF-alpha...
    Sawyer, Richard T; Fontenot, Andrew P; Barnes, Tristan A; Parsons, Charles E; Tooker, Brian C; Maier, Lisa A; Gillespie, May M; Gottschall, E Brigitte; Silveira, Lori; Hagman, James; Newman, Lee S

    American journal of respiratory cell and molecular biology, 02/2007, Letnik: 36, Številka: 2
    Journal Article

    Beryllium (Be)-antigen presentation to Be-specific CD4(+) T cells from the lungs of patients with chronic beryllium disease (CBD) results in T cell proliferation and TNF-alpha secretion. We tested the hypothesis that Be-induced, CBD bronchoalveolar lavage (BAL) T cell, transcription-dependent, TNF-alpha secretion was accompanied by specific transcription factor upregulation. After 6 h of Be stimulation, CBD BAL cells produced a median of 883 pg/ml TNF-alpha (range, 608-1,275 pg/ml) versus 198 pg/ml (range, 116-245 pg/ml) by unstimulated cells. After 12 h CBD BAL cells produced a median of 2,963 pg/ml (range, 99-9,424 pg/ml) TNF-alpha versus 55 pg/ml (range, 0-454) by unstimulated cells. Using real-time RT-PCR, Be-stimulated TNF-alpha production at 6 h was preceded by a 5-fold increase in TNF-alpha pre-mRNA copy number:beta-actin copy number (Be median ratio 0.21; unstimulated median ratio 0.04). The median ratio of mature TNF-alpha mRNA:beta-actin mRNA was upregulated 1.4-fold (Be median ratio 0.17; unstimulated median ratio 0.12). Be exposure in the presence of the transcription inhibitor pentoxifylline (PTX) decreased CBD BAL cell TNF-alpha pre-mRNA levels > 60%, whereas treatment with the mRNA splicing inhibitor 2-aminopurine (2AP) decreased levels 40% relative to Be exposure alone. PTX treatment decreased mature TNF-alpha mRNA levels 50% while 2AP decreased levels > 80%, relative to Be exposure alone. Beryllium exposure specifically upregulated transcription factors AP-1 and NF-kappaB. The data suggest that Be exposure induces transcription-dependent TNF-alpha production, potentially due to upregulation of specific transcription factors.