TRANSCRIPTION FACTOR NUCLEAR FACTOR KAPPA-B REGULATES THE INDUCIBLE EXPRESSION OF THE HUMAN B-1 RECEPTOR GENE IN INFLAMMATION

Expression of the bradykinin B-1 receptor gene is upregulated in vascu lar smooth muscle cells (VSMCs) in response to a variety of inflammato ry stimuli. We isolated the 5'-flanking region of the human bradykinin B-1 receptor gene and examined its promoter activity by transient tra nsfection analysis. This region (-2582 to +34) showed promoter activit y inducible by lipopolysaccharide (LPS), tumor necrosis factor alpha ( TNF-alpha), and interleukin-1 beta (IL-1 beta) in VSMCs. Further delet ion analysis revealed that constructs containing 111 base pairs of 5'- flanking sequence were sufficient for transcriptional induction. Mutag enesis of a nuclear factor ICE (NF-KB)like site at -64 to -55 abolishe d most of the LPS, TNF-alpha; and IL-1 beta inducibility, whereas a mu tation of a cyclic AMP response element at -50 to -43 markedly reduced the basal promoter activity, and a mutation of the activator protein 1 (AP-1) site at -78 to -72 had minimal effects. Nuclear extracts from LPS, TNF-alpha, and IL-1 beta-treated VSMCs, IL-1 beta-treated human hepatoma HepG(2), and human lung fibroblast IMR-90 cells showed strong . inducible binding activity to the NF-kappa B-like site by gel shift assays. These results demonstrated that NF-kappa B-like nuclear factor was involved in the inducible expression of the human bradykinin B-1 receptor gene during inflammatory processes.