Nitration of PPARgamma inhibits ligand-dependent translocation into the nucleus in a macrophage-like cell line, RAW 264.
Nitration of tyrosine residues in proteins has been observed in many inflammatory tissues of arthritis, ulcerative colitis, septic shock and ischemia-reperfusion injury. Although several studies have been carried out, it is still unclear what type of protein is nitrated and whether tyrosine nitration interferes with protein function. Peroxisome proliferator-activated receptor gamma (PPARgamma) is a nuclear receptor whose activation is linked to several physiological pathways including regulation of insulin sensitivity and control of inflammation. PPARgamma possesses several tyrosine residues, which might be potential targets for nitration by peroxynitrite during inflammatory responses. Here we have investigated whether PPARgamma is nitrated in macrophage-like RAW 264 cells and the effect of nitration on the translocation of PPARgamma into the nucleus. Western blot analysis showed that tumor necrosis factor-alpha, lipopolysaccharide or peroxynitrite treatment significantly increases the nitration of PPARgamma. Cell fractionation analysis and immunofluorescence coupled with confocal laser microscopy revealed that nitration of PPARgamma inhibits its ligand-dependent translocation from the cytosol into the nucleus. Together, these results indicate that nitration of PPARgamma during inflammation may be involved in a reduction in the control of inflammatory responses and also in the development of resistance to PPARgamma ligand-based therapies against inflammation.
Shibuya
Atsuhito
A
Department of Pharmacology, Graduate School of Dentistry, Osaka University, 1-8 Yamadaoka, Suita, 565-0871, Osaka, Japan.
Wada
Koichiro
K
Nakajima
Atsushi
A
Saeki
Makio
M
Katayama
Kazufumi
K
Mayumi
Tadanori
T
Kadowaki
Takashi
T
Niwa
Hitoshi
H
Kamisaki
Yoshinori
Y
D021581:Active Transport, Cell Nucleus / Q000187:drug effects / Q000502:physiology; D000818:Animals; D002460:Cell Line; D002467:Cell Nucleus / Q000737:chemistry / Q000378:metabolism*; D002470:Cell Survival / Q000187:drug effects; D004591:Electrophoresis, Polyacrylamide Gel; D008024:Ligands; D008070:Lipopolysaccharides / Q000494:pharmacology; D017737:Macrophages, Peritoneal / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D051379:Mice; D008856:Microscopy, Fluorescence; D030421:Peroxynitrous Acid / Q000378:metabolism* / Q000494:pharmacology; D018160:Receptors, Cytoplasmic and Nuclear / Q000032:analysis / Q000187:drug effects / Q000378:metabolism*; D013347:Subcellular Fractions / Q000737:chemistry; D014157:Transcription Factors / Q000032:analysis / Q000187:drug effects / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
D008024:Ligands; D008070:Lipopolysaccharides; D018160:Receptors, Cytoplasmic and Nuclear; D014157:Transcription Factors; D014409:Tumor Necrosis Factor-alpha; D030421:Peroxynitrous Acid