Peroxisome proliferator-activated receptor-gamma ligands regulate endothelial membrane superoxide production.
Recently, we demonstrated that the peroxisome proliferator-activated receptor-gamma (PPAR-gamma) ligands, either 15-deoxy-Delta12,14-prostaglandin J2 (15d-PGJ2) or ciglitazone, increased endothelial nitric oxide (.NO) release without altering endothelial nitric oxide synthase (eNOS) expression (4). However, the precise molecular mechanisms of PPAR-gamma-stimulated endothelial.NO release remain to be defined. Superoxide anion radical (O2-.) combines with .NO to decrease.NO bioavailability. NADPH oxidase, which produces O2-., and Cu/Zn-superoxide dismutase (Cu/Zn-SOD), which degrades O2-., thereby contribute to regulation of endothelial cell.NO metabolism. Therefore, we examined the ability of PPAR-gamma ligands to modulate endothelial O2-. metabolism through alterations in the expression and activity of NADPH oxidase or Cu/Zn-SOD. Treatment with 10 microM 15d-PGJ2 or ciglitazone for 24 h decreased human umbilical vein endothelial cell (HUVEC) membrane NADPH-dependent O2-. production detected with electron spin resonance spectroscopy. Treatment with 15d-PGJ2 or ciglitazone also reduced relative mRNA levels of the NADPH oxidase subunits, nox-1, gp91phox (nox-2), and nox-4, as measured using real-time PCR analysis. Concordantly, Western blot analysis demonstrated that 15d-PGJ2 or ciglitazone decreased nox-2 and nox-4 protein expression. PPAR-gamma ligands also stimulated both activity and expression of Cu/Zn-SOD in HUVEC. These data suggest that in addition to any direct effects on endothelial.NO production, PPAR-gamma ligands enhance endothelial.NO bioavailability, in part by altering endothelial O2-. metabolism through suppression of NADPH oxidase and induction of Cu/Zn-SOD. These findings further elucidate the molecular mechanisms by which PPAR-gamma ligands directly alter vascular endothelial function.
Hwang
Jinah
J
Division of Pulmonary and Critical Care Medicine, Pulmonary Section, Atlanta Veterans Affairs and Emory University Medical Centers (151-P) 1670 Clairmont Road, Decatur, GA 30033, USA.
Kleinhenz
Dean J
DJ
Lassègue
Bernard
B
Griendling
Kathy K
KK
Dikalov
Sergey
S
Hart
C Michael
CM
D015153:Blotting, Western; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism*; D002478:Cells, Cultured; D004578:Electron Spin Resonance Spectroscopy; D042783:Endothelial Cells / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D007004:Hypoglycemic Agents / Q000494:pharmacology; D008024:Ligands; D019255:NADPH Oxidases / Q000187:drug effects / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism; D047495:PPAR gamma / Q000187:drug effects / Q000378:metabolism*; D015230:Prostaglandin D2 / Q000031:analogs & derivatives* / Q000494:pharmacology*; D012333:RNA, Messenger / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013482:Superoxide Dismutase / Q000096:biosynthesis / Q000187:drug effects; D013481:Superoxides / Q000378:metabolism*; D045162:Thiazolidinediones / Q000494:pharmacology*; D014471:Umbilical Veins / Q000187:drug effects / Q000378:metabolism
C477819:15-deoxyprostaglandin J2; D007004:Hypoglycemic Agents; D008024:Ligands; D047495:PPAR gamma; D012333:RNA, Messenger; D045162:Thiazolidinediones; D013481:Superoxides; D009569:Nitric Oxide; D013482:Superoxide Dismutase; D019255:NADPH Oxidases; D015230:Prostaglandin D2; C039671:ciglitazone