NF-kappa B modulates TNF-alpha production by alveolar macrophages in asymptomatic HIV-seropositive individuals

Local TNF-alpha production in different organs may affect HIV replication a nd pathogenesis. Alveolar macrophages (AMs) obtained by bronchoalveolar lav age from asymptomatic HIV-seropositive and HIV-seronegative individuals did not spontaneously release TNF-alpha, but LPS stimulation of these cells si gnificantly increased TNF-alpha production. We tested whether NF-kappa B af fects TNF-cy production by AMs using N-tosyl-L-phenylalanine chloromethylke tone (TPCK) or N-benzoyl-L-tyrosine ethyl ester (BTEE), which inhibit the d egradation of I kappa B, or tricyclodecan-9-yl-xanthogenate-potassium (D609 ), which inhibits phospholipase C. Alveolar macrophages were exposed to LPS alone and with the chemical protease inhibitors TPCK, BTEE, and D609, NF-k appa B DNA binding induced by LPS treatment of AMs was inhibited by TPCK, B TEE, and D609, These agents also inhibited TNF-alpha mRNA and TNF-alpha pro tein production. After 24 h, the levels of TNF-alpha mRNA reached equilibri um, as assessed by RT-PCR, The levels of NF-kappa B mRNA remained constant under all conditions. The levels of I kappa B-alpha mRNA Here similar after 30, 60, and 180 min, but the I kappa B-beta mRNA concentration was initial ly low and increased over time under all conditions, I kappa B-alpha and I kappa B-alpha protein production was not affected by the chemical protease inhibitors. Our data show that TNF-alpha production by LPS-stimulated AMs f rom asymptomatic HIV-seropositive and -seronegative individuals is regulate d via the phospholipase C pathway and by NF-kappa B DNA binding activity wi thout obvious changes in I kappa B-alpha or I kappa B-beta protein concentr ations.