title: β₁-adrenergic receptor-mediated HO-1 induction, via PI3K and p38 MAPK, by isoproterenol in RAW 264.7 cells leads to inhibition of HMGB1 release in LPS-activated RAW 264.7 cells and increases in survival rate of CLP-induced septic mice.
abstract: High mobility group box (HMGB)-1 plays an important role in sepsis-associated death in experimental studies. Heme oxygenase-1 (HO-1) inducers were reported to reduce HMGB1 release in experimental sepsis. Previously, we reported on the importance of the β₁-adrenergic receptor and protein kinase A pathway in the regulation of HO-1 expression by isoproterenol (ISO) in RAW 264.7 cells. We investigated whether ISO reduces HMGB1 release in LPS-activated RAW 264.7 cells and improves survival rate in septic mice due to HO-1 induction. ISO concentration-dependently increased HO-1 via Nrf-2 translocation and inhibited release of HMGB1 through the β₁-adrenergic receptor (β₁-AR) in LPS-activated RAW 264.7 cells. This conclusion was supported by the finding that dobutamine but not salbutamol increased HO-1 expression in both RAW 264.7 cells. ISO failed to inhibit HMGB1 release when HO-1 expression was suppressed by ZnPPIX, an HO-1 inhibitor in RAW 264.7 cells. ISO significantly inhibited phosphorylation of IκB-α and NF-κB-driven luciferase activity in LPS-activated RAW 264.7 cells. In addition, LY294002, a PI3K inhibitor, and SB203580, a p38 MAPK inhibitor, significantly inhibited not only HO-1 induction but also HMGB1 release by ISO. Importantly, ISO increased HO-1 protein expression in heart and lung tissues, reduced HMGB1 in plasma and increased survival rate in CLP-treated septic mice, which was significantly reversed by co-treatment with ZnPPIX. Taken together, we conclude that inhibition of HMGB1 release during sepsis via β₁-AR-mediated HO-1 induction is a novel mechanism for the beneficial effects of ISO in the treatment of sepsis.
authors.affiliation: Department of Pharmacology School of Medicine, and Institute of Health Sciences, Gyeongsang National University, Jinju 660-290, Republic of Korea.
authors.forename: Yu Mi
authors.initials: YM
authors.lastname: Ha
authors.forename: Sun Ah
authors.initials: SA
authors.lastname: Ham
authors.forename: Young Min
authors.initials: YM
authors.lastname: Kim
authors.forename: Young Soo
authors.initials: YS
authors.lastname: Lee
authors.forename: Hye Jung
authors.initials: HJ
authors.lastname: Kim
authors.forename: Han Geuk
authors.initials: HG
authors.lastname: Seo
authors.forename: Jae Heun
authors.initials: JH
authors.lastname: Lee
authors.forename: Min Kyu
authors.initials: MK
authors.lastname: Park
authors.forename: Ki Churl
authors.initials: KC
authors.lastname: Chang
mesh_terms: D000818:Animals; D002432:Cecum / Q000473:pathology; D002460:Cell Line; D003251:Constriction, Pathologic / Q000150:complications; D024243:HMGB1 Protein / Q000037:antagonists & inhibitors* / Q000378:metabolism; D051547:Heme Oxygenase-1 / Q000096:biosynthesis*; D051550:I-kappa B Kinase / Q000378:metabolism; D007545:Isoproterenol / Q000494:pharmacology*; D008026:Ligation; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008168:Lung / Q000187:drug effects / Q000201:enzymology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D009206:Myocardium / Q000201:enzymology; D051267:NF-E2-Related Factor 2 / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000502:physiology*; D010766:Phosphorylation; D021381:Protein Transport; D011677:Punctures; D018342:Receptors, Adrenergic, beta-1 / Q000502:physiology*; D018805:Sepsis / Q000209:etiology / Q000401:mortality*; D015996:Survival Rate; D048051:p38 Mitogen-Activated Protein Kinases / Q000502:physiology*
chemical_list: D024243:HMGB1 Protein; D008070:Lipopolysaccharides; D051267:NF-E2-Related Factor 2; D016328:NF-kappa B; D018342:Receptors, Adrenergic, beta-1; D051547:Heme Oxygenase-1; D019869:Phosphatidylinositol 3-Kinases; D051550:I-kappa B Kinase; D048051:p38 Mitogen-Activated Protein Kinases; D007545:Isoproterenol