Inhibitory role of kinins on microglial nitric oxide and tumor necrosis factor-α production

• Published in: Peptides (New York, N.Y. : 1980) Vol. 35; no. 2; pp. 172 - 181
• Main Authors: Sarit, Ben-Shmuel, Lajos, Gera, Abraham, Danon, Ron, Apte, Sigal, Fleisher-Berkovich
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01-06-2012
• Subjects: agonists; Animals; Bradykinin; Bradykinin - agonists; Bradykinin - metabolism; brain; Cell Line; encephalitis; Encephalitis - metabolism; Encephalitis - pathology; I-kappa B Kinase - antagonists & inhibitors; I-kappa B Kinase - metabolism; inducible nitric oxide synthase; inflammation; Kinins - metabolism; Lipopolysaccharides; messenger RNA; Mice; Microglia; Microglia - metabolism; necrosis; neuroglia; neuropeptides; neurotoxicity; NF-kappa B - genetics; NF-kappa B - metabolism; NF-kappa B p50 Subunit - metabolism; Nitric oxide; Nitric Oxide - biosynthesis; Nitric Oxide Synthase Type II - genetics; Nitric Oxide Synthase Type II - metabolism; Nuclear factor-κB; Rats; receptors; RNA, Messenger - genetics; RNA, Messenger - metabolism; transcription factor NF-kappa B; Transcription Factor RelA - metabolism; Transcription, Genetic; tumor necrosis factor-alpha; Tumor Necrosis Factor-alpha - biosynthesis; Tumor Necrosis Factor-alpha - genetics; Tumor necrosis factor-α; Tumor necrosis factor-α; Nuclear factor-κB; Bradykinin; Nitric oxide; Microglia
• ISSN: 0196-9781; 1873-5169
• DOI: 10.1016/j.peptides.2012.03.026

► Three kinin agonists attenuate LPS-induced NO and TNF-α production in BV2 cells. ► Bradykinin reduced basal NO and TNF-α production in BV2 cells. ► Anti-inflammatory effects of bradykinin were confirmed in primary microglia. ► Three kinin agonists reduce LPS-induced iNOS and TNF-α protein and mRNA levels in BV2 cells. ► Bradykinin abolishes LPS-induced NF-κB pathway activation in BV2 cells.
Brain inflammation is sustained by chronic activation of microglia and the over-production of pro-inflammatory cytokines and nitric oxide (NO), which in turn can be highly neurotoxic. Microglial activation can be regulated by neuropeptides such as bradykinin (BK) and other members of the kinin family. Kinins are well known inflammatory regulators outside the CNS. Although the kinin system is well distributed throughout the brain, the precise role of BK in the CNS is not yet clear. The aim of this study was to examine and characterize the effects of BK and related kinins on the production of NO and TNF-α in microglia. We found that BK and selective agonists for both B1 and B2 receptors, attenuated both NO and TNF-α levels in the media of BV2 microglial cells that had been stimulated with LPS. The effects of BK that were observed in BV2 cells were confirmed in primary neonatal rat microglial cells as well. In addition, all kinin agonists reduced the expression of iNOS and TNF-α protein and mRNA levels in LPS-stimulated BV2 cells. Also, while LPS activated the nuclear factor-κB (NF-κB) pathway, BK inhibited NF-κB activation by preventing degradation of the κB protein (IκB) inhibitor, abolishing translocation of p65 and p50 subunits to the nucleus and inhibiting NF-κB transcription activity. These results suggest a role for bradykinin in modulation of glial inflammation, as evidenced by attenuation of NO and TNF-α synthesis pathways in activated microglial cells.