Bradykinin-induced IL-6 expression through bradykinin B2 receptor, phospholipase C, protein kinase Cdelta and NF-kappaB pathway in human synovial fibroblasts.
Bradykinin (BK) is an inflammatory mediator, and shows elevated levels in regions of severe injury and inflammatory diseases. It has been shown to induce interleukin-6 (IL-6) expression in inflammatory responses in rheumatoid arthritis. We investigated the signaling pathway involved in IL-6 production caused by BK in synovial fibroblasts. BK caused concentration- and time-dependent increases in IL-6 production. By using pharmacological inhibitors or genetic inhibition of the BK receptor, siRNA revealed that B2 but not B1 BK receptors are involved in BK-mediated up-regulation of IL-6. BK-mediated IL-6 production was attenuated by phospholipase C inhibitor (U73122), protein kinase Cdelta inhibitor (rottlerin), NF-kappaB inhibitor (PDTC), IkappaB protease inhibitor (TPCK) and NF-kappaB inhibitor peptide. Stimulation of synovial fibroblasts with BK activated IkappaB kinase alpha/beta (IKK alpha/beta), IkappaBalpha phosphorylation, IkappaBalpha degradation, p65 phosphorylation at Ser(276), p65 and p50 translocation from the cytosol to the nucleus and kappaB-luciferase activity. BK mediated an increase of IKK alpha/beta and IkappaBalpha phosphorylation, kappaB-luciferase activity and p65 and p50 binding to the NF-kappaB element was inhibited by B2 BK receptor antagonist (HOE140), U73122 and rottlerin. Our results suggest that BK increased IL-6 production in synovial fibroblasts via the B2 BK receptor/PI-PLC/PKCdelta/and NF-kappaB signaling pathway.
Lee
Cheng-Hung
CH
Department of Orthopaedics, Taichung Veterans General Hospital, Taichung, Taiwan.
Shieh
Dong-Chen
DC
Tzeng
Chung-Yuh
CY
Chen
Chao-Ping
CP
Wang
Shun-Ping
SP
Chiu
Yung-Cheng
YC
Huang
Chun-Yin
CY
Hsu
Chin-Jung
CJ
Fong
Yi-Chin
YC
Tang
Chih-Hsin
CH
D001920:Bradykinin / Q000494:pharmacology*; D065094:Bradykinin B2 Receptor Antagonists; D002478:Cells, Cultured; D005347:Fibroblasts / Q000378:metabolism*; D017930:Genes, Reporter; D006801:Humans; D051550:I-kappa B Kinase / Q000502:physiology; D015850:Interleukin-6 / Q000096:biosynthesis*; D008156:Luciferases / Q000378:metabolism; D008954:Models, Biological; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000378:metabolism; D010766:Phosphorylation; D051745:Protein Kinase C-delta / Q000037:antagonists & inhibitors / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis; D043782:Receptor, Bradykinin B2 / Q000378:metabolism; D015398:Signal Transduction; D013583:Synovial Membrane / Q000166:cytology; D051996:Transcription Factor RelA / Q000378:metabolism; D014162:Transfection; D010738:Type C Phospholipases / Q000037:antagonists & inhibitors / Q000378:metabolism; D015854:Up-Regulation
D065094:Bradykinin B2 Receptor Antagonists; D015850:Interleukin-6; D016328:NF-kappa B; D012333:RNA, Messenger; D043782:Receptor, Bradykinin B2; D051996:Transcription Factor RelA; D008156:Luciferases; D051550:I-kappa B Kinase; D051745:Protein Kinase C-delta; D010738:Type C Phospholipases; D001920:Bradykinin