title: Prostacyclin-induced peroxisome proliferator-activated receptor-alpha translocation attenuates NF-kappaB and TNF-alpha activation after renal ischemia-reperfusion injury.
abstract: Prostacyclin and peroxisome proliferator-activated receptors (PPAR) protect against ischemia-reperfusion (I/R) injury by the induction of an anti-inflammatory pathway. In this study, we examined the prostacyclin-enhanced protective effect of PPARalpha in I/R-induced kidney injury. PPAR-alpha reduced the NF-kappaB-induced overexpression of TNF-alpha and apoptosis in cultured kidney cells. In a murine model, pretreating wild-type (WT) mice with a PPAR-alpha activator, docosahexaenoic acid (DHA), significantly reduced I/R-induced renal dysfunction (lowered serum creatinine and urea nitrogen levels), apoptotic responses (decreased apoptotic cell number and caspase-3, -8 activation), and NF-kappaB activation. By comparison, I/R-induced injury was exacerbated in PPAR-alpha knockout mice. This indicated that PPAR-alpha attenuated renal I/R injury via NF-kappaB-induced TNF-alpha overexpression. Overexpression of prostacyclin using an adenovirus could also induce PPAR-alpha translocation from the cytosol into the nucleus to inhibit caspase-3 activation. This prostacyclin/PPAR-alpha pathway attenuated TNF-alpha promoter activity by binding to NF-kappaB. Using a cAMP inhibitor (CAY10441) and a prostacyclin receptor antibody, we also found that there was another prostacyclin/IP receptor/cAMP pathway that could inhibit TNF-alpha production. Taken together, our results demonstrate for the first time that prostacyclin induces the translocation of PPAR-alpha from the cytosol into the nucleus and attenuates NF-kappaB-induced TNF-alpha activation following renal I/R injury. Treatments that can augment prostacyclin, PPAR-alpha, or the associated signaling pathways may ameliorate conditions associated with renal I/R injury.
authors.affiliation: Graduate Institute of Clinical Medicine, College of Medicine, Taipai Medical University, Taiwan.
authors.forename: Hsi-Hsien
authors.initials: HH
authors.lastname: Chen
authors.forename: Tzen-Wen
authors.initials: TW
authors.lastname: Chen
authors.forename: Heng
authors.initials: H
authors.lastname: Lin
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D004281:Docosahexaenoic Acids; D011464:Epoprostenol / Q000378:metabolism*; D007677:Kidney Function Tests; D008297:Male; D051379:Mice; D016328:NF-kappa B / Q000378:metabolism*; D047493:PPAR alpha / Q000378:metabolism*; D051381:Rats; D015427:Reperfusion Injury / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*
chemical_list: D016328:NF-kappa B; D047493:PPAR alpha; D014409:Tumor Necrosis Factor-alpha; D004281:Docosahexaenoic Acids; D011464:Epoprostenol