title: PPARγ stabilizes HO-1 mRNA in monocytes/macrophages which affects IFN-β expression.
abstract: NADPH oxidase activation in either RAW264.7 cells or peritoneal macrophages (PM) derived from PPARγ wild-type mice increased reactive oxygen species (ROS) formation, caused PPARγ activation, heme oxygenase-1 (HO-1) induction, and concomitant IFN-β expression. In macrophages transduced with a dominant negative (d/n) mutant of PPARγ (RAW264.7 AF2) as well as PPARγ negative PM derived from Mac-PPARγ-KO mice, NADPH oxidase-dependent IFN-β expression was attenuated. As the underlying mechanism, we noted decreased HO-1 mRNA stability in RAW264.7 AF2 cells as well as PPARγ negative PM, compared to either parent RAW264.7 cells or wild-type PM. Assuming mRNA stabilization of HO-1 by PPARγ we transfected macrophages with a HO-1 3'-UTR reporter construct. The PPARγ agonist rosiglitazone significantly up-regulated luciferase expression in RAW264.7 cells, while it remained unaltered in RAW264.7 AF2 macrophages. Deletion of each of two AU-rich elements in the 3'-UTR HO-1 decreased luciferase activity in RAW264.7 cells. Using LPS as a NADPH oxidase activator, PM from Mac-PPARγ-KO mice showed a decreased HO-1 mRNA half-life in vitro and in vivo compared to PPARγ wild-type mice. These data identified a so far unappreciated role of PPARγ in stabilizing HO-1 mRNA, thus, contributing to the expression of the HO-1 target gene IFN-β.
authors.affiliation: Institute of Biochemistry I-Pathobiochemistry, Faculty of Medicine, Goethe-University Frankfurt, 60590 Frankfurt, Theodor-Stern-Kai 7, Germany. v_knethen@zbc.kgu.de
authors.forename: Andreas
authors.initials: A
authors.lastname: von Knethen
authors.forename: Holger
authors.initials: H
authors.lastname: Neb
authors.forename: Virginie
authors.initials: V
authors.lastname: Morbitzer
authors.forename: Martina Victoria
authors.initials: MV
authors.lastname: Schmidt
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Kuhn
authors.forename: Laura
authors.initials: L
authors.lastname: Kuchler
authors.forename: Bernhard
authors.initials: B
authors.lastname: Brüne
mesh_terms: D020413:3' Untranslated Regions; D000818:Animals; D001483:Base Sequence; D015153:Blotting, Western; D002460:Cell Line; D017931:DNA Primers; D006419:Heme Oxygenase (Decyclizing) / Q000235:genetics*; D016899:Interferon-beta / Q000378:metabolism*; D008264:Macrophages / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D009000:Monocytes / Q000378:metabolism*; D047495:PPAR gamma / Q000502:physiology*; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000235:genetics*
chemical_list: D020413:3' Untranslated Regions; D017931:DNA Primers; D047495:PPAR gamma; D012333:RNA, Messenger; D016899:Interferon-beta; D006419:Heme Oxygenase (Decyclizing)