title: Nrf2 regulates PU.1 expression and activity in the alveolar macrophage.
abstract: Alveolar macrophage (AM) immune function depends on the activation of the transcription factor PU.1 by granulocyte macrophage colony-stimulating factor. We have determined that chronic alcohol ingestion dampens PU.1 signaling via an unknown zinc-dependent mechanism; specifically, although PU.1 is not known to be a zinc-dependent transcription factor, zinc treatment reversed alcohol-mediated dampening of PU.1 signaling. Nuclear factor (erythroid-derived 2)-like 2 (Nrf2), a zinc-dependent basic leucine zipper protein essential for antioxidant defenses, is also impaired by chronic alcohol ingestion and enhanced by zinc treatment. We hypothesized that the response of PU.1 to zinc treatment may result from the action of Nrf2 on PU.1. We first performed Nrf2/PU.1 protein coimmunoprecipitation on a rat AM cell line (NR8383) and found no evidence of protein-protein interactions. We then found evidence of increased Nrf2 binding to the PU.1 promoter region by chromatin immunoprecipitation. We next activated Nrf2 using either sulforaphane or an overexpression vector and inhibited Nrf2 with silencing RNA to determine whether Nrf2 could actively regulate PU.1. Nrf2 activation increased protein expression of both factors as well as gene expression of their respective downstream effectors, NAD(P)H dehydrogenase[quinone] 1 (NQO1) and cluster of differentiation antigen-14 (CD14). In contrast, Nrf2 silencing decreased the expression of both proteins, as well as gene expression of their effectors. Activating and inhibiting Nrf2 in primary rat AMs resulted in similar effects. Taken together, these findings suggest that Nrf2 regulates the expression and activity of PU.1 and that antioxidant response and immune activation are coordinately regulated within the AM.
authors.affiliation: Division of Pulmonary, Allergy, Critical Care & Sleep Medicine, Emory University School of Medicine, Atlanta, Georgia; and bashar.staitieh@emory.edu.
authors.forename: Bashar S
authors.initials: BS
authors.lastname: Staitieh
authors.affiliation: Division of Pulmonary, Allergy, Critical Care & Sleep Medicine, Emory University School of Medicine, Atlanta, Georgia; and Atlanta Veterans Affairs Medical Center, Decatur, Georgia.
authors.forename: Xian
authors.initials: X
authors.lastname: Fan
authors.affiliation: Division of Pulmonary, Allergy, Critical Care & Sleep Medicine, Emory University School of Medicine, Atlanta, Georgia; and.
authors.forename: Wendy
authors.initials: W
authors.lastname: Neveu
authors.affiliation: Division of Pulmonary, Allergy, Critical Care & Sleep Medicine, Emory University School of Medicine, Atlanta, Georgia; and Atlanta Veterans Affairs Medical Center, Decatur, Georgia.
authors.forename: David M
authors.initials: DM
authors.lastname: Guidot
mesh_terms: D000818:Animals; D002460:Cell Line; D005786:Gene Expression Regulation; D018950:Lipopolysaccharide Receptors / Q000235:genetics / Q000378:metabolism; D016676:Macrophages, Alveolar / Q000166:cytology / Q000378:metabolism*; D016660:NAD(P)H Dehydrogenase (Quinone) / Q000235:genetics / Q000378:metabolism; D051267:NF-E2-Related Factor 2 / Q000235:genetics / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis* / Q000235:genetics; D051381:Rats; D011916:Rats, Inbred F344; D020218:Response Elements; D015534:Trans-Activators / Q000096:biosynthesis* / Q000235:genetics; D015032:Zinc / Q000494:pharmacology; D000099232:Proto-Oncogene Protein Spi-1
chemical_list: D018950:Lipopolysaccharide Receptors; D016660:NAD(P)H Dehydrogenase (Quinone); D051267:NF-E2-Related Factor 2; D011518:Proto-Oncogene Proteins; D015534:Trans-Activators; D015032:Zinc; D000099232:Proto-Oncogene Protein Spi-1; C495637:Nfe2l2 protein, rat; C507703:NQO1 protein, rat
keywords: PU.1; alveolar macrophage; nuclear factor (erythroid-derived 2)-like 2
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