Tobacco-smoke-inducible human haem oxygenase-1 gene expression: role of distinct transcription factors and reactive oxygen intermediates.
Exposure of eukaryotic cells to a variety of reactive-oxygen-intermediate (ROI)-mediated sources of cellular injury, including heavy metals and UV radiation, induces the expression of heat-shock (HS) and stress-related genes among which is a 32-34 kDa protein identified as inducible haem oxygenase-1 (HO-1). We previously showed that tobacco smoke (TS), a potent source of oxidants leading to oxidative stress, induces both HS proteins (HSPs) and HO-1 in normal human monocytes. Here we investigated the induction mechanisms of human HO-1 gene expression by TS in the human premonocytic line U937. Northern blotting and flow cytometry revealed a dose- and time-dependent induction of HO-1 mRNA and protein by TS. In order to clarify the role of transacting factors in this induction, electrophoretic mobility-shift analysis was performed with nuclear extracts from control, TS-, cadmium (Cd)- or H(2)O(2)-exposed cells, incubated with consensus elements and binding sites of the promoter region of HO-1[heat-shock factor (HSF), nuclear factor kappaB (NF-kappaB) and activator protein-1 (AP-1)] and the cadmium-responsive element (CdRE) isolated by Takeda, Ishizawa, Sato, Yoshida and Shibahara [(1994) J. Biol. Chem. 269, 22858-22867]. We report an inhibition of NF-kappaB activation by TS, no effect on AP-1 and a strong activation of CdRE-binding activity, whereas cadmium chelation from TS only partially prevented HO-1 induction. H(2)O(2) also activated the CdRE-binding activity, and pretreatment with N-acetyl-L-cysteine, which replenishes the intracellular levels of GSH, suppressed, in TS-treated cells, both the CdRE-binding activity and the increased HO-1 expression.
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Laboratoire de Physiologie Respiratoire, UFR Cochin Port-Royal, 24 rue du Faubourg Saint-Jacques, 75014 Paris, France. Florence.Favatier@cochin.univ-paris5.fr
Polla
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D001483:Base Sequence; D017931:DNA Primers; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects* / Q000502:physiology; D005978:Glutathione / Q000378:metabolism; D006419:Heme Oxygenase (Decyclizing) / Q000235:genetics*; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D009154:Mutation; D012333:RNA, Messenger / Q000235:genetics; D017382:Reactive Oxygen Species; D012906:Smoke; D014157:Transcription Factors / Q000502:physiology*; D020298:U937 Cells
D017931:DNA Primers; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D012906:Smoke; D014157:Transcription Factors; D006861:Hydrogen Peroxide; D006419:Heme Oxygenase (Decyclizing); D005978:Glutathione