title: Compound C stimulates heme oxygenase-1 gene expression via the Nrf2-ARE pathway to preserve human endothelial cell survival.
abstract: We recently identified adenosine monophosphate-activated protein kinase (AMPK) as a novel inducer of heme oxygenase-1 (HO-1) and surprisingly found that compound C (6-[4-(2-piperidin-1-yl-ethoxy)-phenyl]-3-pyridin-4-yl-pyrazolo[1,5-a] pyrimidine), a cell-permeable inhibitor of AMPK, could also elevate HO-1 suggesting other AMPK-independent actions for this agent. In this study, we investigated the biochemical mechanism by which compound C stimulates HO-1 expression in human endothelial cells (ECs) and determined the biological significance of the induction of HO-1 by compound C in these cells. Compound C stimulated a concentration- and time-dependent increase in HO-1 expression and an increase in HO-1 promoter activity that was abrogated by mutating the antioxidant responsive elements (AREs) in the HO-1 promoter or by overexpressing a dominant negative mutant of NF-E2-related factor 2 (Nrf2). Compound C also stimulated Nrf2 expression this was associated with an increase in the production of reactive oxygen species and with a decline in intracellular glutathione levels. Interestingly, the glutathione donor N-acetyl-l-cysteine or the NADPH oxidase inhibitor apocynin blocked the induction of HO-1 by compound C. Finally, compound C stimulated EC death and this was potentiated by silencing HO-1 expression and reversed by the administration of CO, biliverdin, or bilirubin. In conclusion, this study demonstrates that compound C stimulates HO-1 gene expression in human vascular endothelium via the activation of the Nrf2/ARE signaling pathway to counteract compound C-mediated cell death. The ability of compound C to induce HO-1 expression may contribute to the pleiotropic actions of this agent and suggest caution when using compound C to probe for AMPK functions.
authors.affiliation: Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO 65212, USA.
authors.forename: Xiao-Ming
authors.initials: XM
authors.lastname: Liu
authors.forename: Kelly J
authors.initials: KJ
authors.lastname: Peyton
authors.forename: Ahmad R
authors.initials: AR
authors.lastname: Shebib
authors.forename: Hong
authors.initials: H
authors.lastname: Wang
authors.forename: William
authors.initials: W
authors.lastname: Durante
mesh_terms: D055372:AMP-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D000975:Antioxidants / Q000378:metabolism; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000166:cytology* / Q000187:drug effects / Q000201:enzymology*; D015971:Gene Expression Regulation, Enzymologic; D051547:Heme Oxygenase-1 / Q000096:biosynthesis*; D006801:Humans; D051267:NF-E2-Related Factor 2 / Q000096:biosynthesis*; D011720:Pyrazoles / Q000494:pharmacology*; D011743:Pyrimidines / Q000494:pharmacology*; D020218:Response Elements / Q000187:drug effects / Q000502:physiology*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology
chemical_list: D000975:Antioxidants; D051267:NF-E2-Related Factor 2; D011720:Pyrazoles; D011743:Pyrimidines; C516138:dorsomorphin; D051547:Heme Oxygenase-1; D055372:AMP-Activated Protein Kinases