NO and peroxynitrite modulate NF-κB-dependent transcriptional activity in HPMCs. (a) HPMCs transiently transfected with pNF-κB-Luc were treated with HHb (10 nM) alone or in combination with the iNOS inhibitors 1400W (10 μM) and L-NAME (100 μM), dexamethasone (Dex, 1 μM) or PDTC (100 μM) for 12 h, after which luciferase activity was measured, n=12. (b) NF-κB-dependent transcription was further determined in HPMCs treated for the same time period with S-nitroso-N-acetylpenicillamine (SNAP, 10 μM) and sodium nitroprusside (SNP 100 μM) either alone or in the presence of HHb. HHb was also coincubated with PDTC (100 μM), n=9. (c) NF-κB-dependent transcription was determined in HPMCs treated for 8 h with HHb alone or in combination with the peroxynitrite scavengers uric acid (0.1, 1, and 10 μM) and Trolox (1, 5, and 10 μM) or PDTC (100 μM), n=9. (d) Representative immunoblot for nitrated protein expressions after exposure for 12 h to either NHb or HHb (both at 10 nM) or HHb in combination with Tempol or DMTU (100 μM and 1 mM, respectively).*P⩽0.05 vs basal; **P⩽0.05 vs HHb-treated cells.