活性酸素の生化学 - tokushima-u.ac.jp

1 2 2 1 3 1 2 3 1S11S22S12S1* z x x* y* y3O21O2O2-O22-3 Reactive Oxygen Species (ROS)singlet oxygensuperoxide anionhydrogenperoxide 3 1 hemosiderin ferritin ( transferrin , lactoferrin 2 3 1 ab Initiation ( Prolongation R + O2 ROO ROO + RH ROOH + R Termination 2 R RR2 ROO O2+ ROORROO + R ROOR-H L-arginineNO synthase (NOS )Neuronal NOS (nNOS or NOS1).))

2 Inducible NOS (iNOS or NOS2) Endothelial NOS (eNOS or NOS3 NO O2- peroxinitrate superoxide dismutase (SOD)Cu, ZnSOD ( SOD1 MnSOD SOD2 ECSOD SOD3 O2-+ O2-+ 2 H+ O2+ H2O2 catalase 2 H2O2 2 H2O + O2 glutathione peroxidase 2 GSH + H2O2 GSSG + 2 H2O2 GSH + ROOH GSSG + ROH + H2O - glutathione S-transferaseGSH + ROOH GSOH + ROHGSOH + GSH GSSG + H2O Glutathione Oxidation Reduction (Redox) Cycle Mn-SODCu, Zn-SOD (transferrin) (lactoferrin) (hemosiderin) (ferritin) (celuroplasmin) (metallothionein) SH 1 7 - DNA (8-HDG) ARE antioxidant response element Nuclear Respiratory Factor 2 (NRF2) NADPH oxidase chronic granulomatous disease.))

3 CGD NADPH oxidase gp91phox p22phox p47phox p67phox PMNS pecificGranules PrimaryGranules PMN Phagocytosis SuperoxideMPOCl-H2O22O2-2O2+HOCl(~bleach )pH = Proteins & PeptidesProteases FR DeLeo COOHNH2 Dinauer and coworkers, 1998 Segal and coworkers, 1997 Flavocytochrome b558gp91phoxp22phoxFeFeN 240 COOHNH2N 132N 149 VIIVIII NADPH Oxidase: unassembled & inactive2O2-CYTOPLASMp67p47p40+Sequester ed SH3 Domains and Cationic Region2O2gp91phoxp22-phoxFe2e-Fe Conformational changes of p47phoxPX (wt)SH3PN------CSH3SH3SH3PC---N---Protei n kinase(s)Resting cellStimulated cellPPautoinhibitory region RhoGDIRacGDPRhoGDIACTIVATEDRESTINGP hosphorylationCYTOPLASMp67p47p401+Seques tered SH3 Domains and Cationic Region?

4 2 NADPH Oxidase Activation and Assembly32O22O2-gp91phoxp22-phoxFep67p40 67 RacGTPRap1 ANADPHFAD2e-FePPP13 NADPHFAD98p67p47p401254PP3 NAD(P)H oxidaseszPhagocyte NADPH oxidase (gp91phox) Nox2zNon-phagocyte oxidase(smooth muscle cells, endothelial cells, fibroblasts)zGastric pit cell NAD(P)H oxidase (Teshima, Gastroenterology 1998)zMitogen oxidase 1 (Mox1) (Lambeth, Nature 1999)Nox1zRenox (Leto, ProNAS 2000; Sumimoto, JBC 2001) Nox4zThox 1, 2 (Duphy, JBC 1999; Edens, JBC 2001) Duox1, 2zNox3 (Kikuchi, Gene 2000) Nox3zNox5 (Lambeth, JBC 2001) Nox5zNox organizer 1, Nox activator 1 (Leto; Krause; Sumimoto; JBCs 2003)zNox1 in innate immunity (Kawahara et al. J Immunol 2004) Nox2 (gp91phox) Nox1 Nox3 Nox4 Nox5 Duox1 Duox2 NADPH oxidase (Nox) / Dual oxidase (Duox) family(Lambeth et al, Trends. Biochem. , Gordon Research Conference, 2001)outsideinsideCOOHNH2 NADPHFADHHHHIIIIIIIVVVIFeFeNox1 FAD , NADPH binding domainsEF-handCa++-binding domain1 x transmembranePeroxidase domain6 x transmembrane Functions of the Nox/Duox familyNox1: local host defense, inflammationcell growth, transformation (?)

5 Regulation of vascular toneNox2 : host defense, recognition & memory ?Nox3 : development, otoconial morphogenesisNox4 : aging, atherosclerosis, oxygen sensingNox5 : regulation of immune cell functionsDuox1, Duox2 : thyroid hormone synthesishost defens