title: Apo J/clusterin expression and secretion: evidence for 15-deoxy-Δ(12,14)-PGJ(2)-dependent mechanism.
abstract: Cyclooxygenase-2 (Cox-2) and Apo J/clusterin are involved in inflammatory resolution and have each been reported to inhibit NF-κB signalling. Using a well-validated rat pheochromocytoma (PC12) cell culture model of Cox-2 over-expression the current study investigated inter-dependence between Cox-2 and clusterin with respect to induction of expression and impact on NF-κB signalling. Both gene expression and immunoblot analysis confirmed that intracellular and secreted levels of clusterin were elevated in Cox-2 over-expressing cells (PCXII). Clusterin expression was increased in control (PCMT) cells in a time- and dose-dependent manner by 15-deoxy-Δ(12,14)-prostaglandin J(2) (15d-PGJ(2)), but not PGE(2), and inhibited in PCXII cells by pharmacological Cox inhibition. In PCXII cells, inhibition of two transcription factors known to be activated by 15d-PGJ(2), heat shock factor 1 (HSF-1) and peroxisome proliferator activated receptor (PPAR)γ, by transcription factor oligonucleotide decoy and antagonist (GW9662) treatment, respectively, reduced clusterin expression. While PCXII cells exhibited reduced TNF-α-induced cell surface ICAM-1 expression, IkB phosphorylation and degradation were similar to control cells. With respect to the impact of Cox-2-dependent clusterin upregulation on NF-κB signalling, basal levels of IκB were similar in control and PCXII cells, and no evidence for a physical association between clusterin and phospho-IκB was obtained. Moreover, while PCXII cells exhibited reduced NF-κB transcriptional activity, this was not restored by clusterin knock-down. These results indicate that Cox-2 induces clusterin in a 15d-PGJ(2)-dependent manner, and via activation of HSF-1 and PPARγ. However, the results do not support a model whereby Cox-2/15d-PGJ(2)-dependent inhibition of NF-κB signalling involves clusterin.
authors.affiliation: Nutrition and Metabolism Group, Centre for Public Health, Queen's University Belfast, Pathology Building, RVH, Grosvenor Road, BT12 6BJ, Belfast, Northern Ireland, UK.
authors.forename: Damien
authors.initials: D
authors.lastname: Gates
authors.forename: Kiera
authors.initials: K
authors.lastname: Dollin
authors.forename: Roisin
authors.initials: R
authors.lastname: Connolly
authors.forename: Ian
authors.initials: I
authors.lastname: Young
authors.forename: Lesley
authors.initials: L
authors.lastname: Powell
authors.forename: Jane
authors.initials: J
authors.lastname: McEneny
authors.forename: Martin
authors.initials: M
authors.lastname: Gleave
authors.forename: Ann
authors.initials: A
authors.lastname: McGinty
mesh_terms: D000818:Animals; D051152:Clusterin / Q000378:metabolism*; D051546:Cyclooxygenase 2 / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D055785:Gene Knockdown Techniques; D000076249:Heat Shock Transcription Factors; D018799:Intercellular Adhesion Molecule-1 / Q000378:metabolism; D007544:Isopropyl Thiogalactoside / Q000494:pharmacology; D016328:NF-kappa B / Q000378:metabolism; D016716:PC12 Cells; D047495:PPAR gamma / Q000378:metabolism; D015230:Prostaglandin D2 / Q000031:analogs & derivatives* / Q000378:metabolism; D051381:Rats; D015398:Signal Transduction / Q000187:drug effects; D014157:Transcription Factors / Q000378:metabolism; D014158:Transcription, Genetic / Q000187:drug effects; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D015854:Up-Regulation / Q000187:drug effects
chemical_list: C097240:15-deoxy-delta(12,14)-prostaglandin J2; D051152:Clusterin; D004268:DNA-Binding Proteins; D000076249:Heat Shock Transcription Factors; D016328:NF-kappa B; D047495:PPAR gamma; D014157:Transcription Factors; D014409:Tumor Necrosis Factor-alpha; D018799:Intercellular Adhesion Molecule-1; D007544:Isopropyl Thiogalactoside; D051546:Cyclooxygenase 2; C489691:Ptgs2 protein, rat; D015230:Prostaglandin D2