title: Glutathione S-transferase pi modulates NF-κB activation and pro-inflammatory responses in lung epithelial cells.
abstract: Nuclear Factor kappa B (NF-κB) is a transcription factor family critical in the activation of pro- inflammatory responses. The NF-κB pathway is regulated by oxidant-induced post-translational modifications. Protein S-glutathionylation, or the conjugation of the antioxidant molecule, glutathione to reactive cysteines inhibits the activity of inhibitory kappa B kinase beta (IKKβ), among other NF-κB proteins. Glutathione S-transferase Pi (GSTP) is an enzyme that has been shown to catalyze protein S-glutathionylation (PSSG) under conditions of oxidative stress. The objective of the present study was to determine whether GSTP regulates NF-κB signaling, S-glutathionylation of IKK, and subsequent pro-inflammatory signaling. We demonstrated that, in unstimulated cells, GSTP associated with the inhibitor of NF-κB, IκBα. However, exposure to LPS resulted in a rapid loss of association between IκBα and GSTP, and instead led to a protracted association between IKKβ and GSTP. LPS exposure also led to increases in the S-glutathionylation of IKKβ. SiRNA-mediated knockdown of GSTP decreased IKKβ-SSG, and enhanced NF-κB nuclear translocation, transcriptional activity, and pro-inflammatory cytokine production in response to lipopolysaccharide (LPS). TLK117, an isotype-selective inhibitor of GSTP, also enhanced LPS-induced NF-κB transcriptional activity and pro-inflammatory cytokine production, suggesting that the catalytic activity of GSTP is important in repressing NF-κB activation. Expression of both wild-type and catalytically-inactive Y7F mutant GSTP significantly attenuated LPS- or IKKβ-induced production of GM-CSF. These studies indicate a complex role for GSTP in modulating NF-κB, which may involve S-glutathionylation of IKK proteins, and interaction with NF-κB family members. Our findings suggest that targeting GSTP is a potential avenue for regulating the activity of this prominent pro-inflammatory and immunomodulatory transcription factor.
authors.affiliation: Department of Pathology and Laboratory Medicine, The University of Vermont, Burlington, VT, United States.
authors.forename: Jane T
authors.initials: JT
authors.lastname: Jones
authors.affiliation: Department of Pathology and Laboratory Medicine, The University of Vermont, Burlington, VT, United States.
authors.forename: Xi
authors.initials: X
authors.lastname: Qian
authors.affiliation: Department of Pathology and Laboratory Medicine, The University of Vermont, Burlington, VT, United States.
authors.forename: Jos L J
authors.initials: JL
authors.lastname: van der Velden
authors.affiliation: Department of Pathology and Laboratory Medicine, The University of Vermont, Burlington, VT, United States.
authors.forename: Shi Biao
authors.initials: SB
authors.lastname: Chia
authors.affiliation: Department of Pathology and Laboratory Medicine, The University of Vermont, Burlington, VT, United States.
authors.forename: David H
authors.initials: DH
authors.lastname: McMillan
authors.affiliation: Department of Chemistry, The University of Vermont, Burlington, VT, United States.
authors.forename: Stevenson
authors.initials: S
authors.lastname: Flemer
authors.affiliation: Department of Pathology and Laboratory Medicine, The University of Vermont, Burlington, VT, United States.
authors.forename: Sidra M
authors.initials: SM
authors.lastname: Hoffman
authors.affiliation: Department of Pathology and Laboratory Medicine, The University of Vermont, Burlington, VT, United States.
authors.forename: Karolyn G
authors.initials: KG
authors.lastname: Lahue
authors.affiliation: Department of Pathology and Laboratory Medicine, The University of Vermont, Burlington, VT, United States.
authors.forename: Robert W
authors.initials: RW
authors.lastname: Schneider
authors.affiliation: Department of Pathology and Laboratory Medicine, The University of Vermont, Burlington, VT, United States.
authors.forename: James D
authors.initials: JD
authors.lastname: Nolin
authors.affiliation: Department of Pathology and Laboratory Medicine, The University of Vermont, Burlington, VT, United States.
authors.forename: Vikas
authors.initials: V
authors.lastname: Anathy
authors.affiliation: Department of Pathology and Laboratory Medicine, The University of Vermont, Burlington, VT, United States.
authors.forename: Albert
authors.initials: A
authors.lastname: van der Vliet
authors.affiliation: Department of Pharmaceutical and Biomedical Sciences, Medical University of South Carolina, Charleston, SC, United States.
authors.forename: Danyelle M
authors.initials: DM
authors.lastname: Townsend
authors.affiliation: Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Medical University of South Carolina, Charleston, SC, United States.
authors.forename: Kenneth D
authors.initials: KD
authors.lastname: Tew
authors.affiliation: Department of Pathology and Laboratory Medicine, The University of Vermont, Burlington, VT, United States. Electronic address: yvonne.janssen@uvm.edu.
authors.forename: Yvonne M W
authors.initials: YM
authors.lastname: Janssen-Heininger
mesh_terms: D000818:Animals; D001249:Asthma / Q000139:chemically induced / Q000235:genetics* / Q000473:pathology; D002460:Cell Line; D004195:Disease Models, Animal; D004847:Epithelial Cells / Q000378:metabolism / Q000473:pathology; D054477:Glutaredoxins / Q000378:metabolism; D051549:Glutathione S-Transferase pi / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D051550:I-kappa B Kinase / Q000235:genetics* / Q000378:metabolism; D007249:Inflammation / Q000235:genetics* / Q000378:metabolism; D008070:Lipopolysaccharides / Q000633:toxicity; D008168:Lung / Q000378:metabolism* / Q000473:pathology; D051379:Mice; D016328:NF-kappa B / Q000235:genetics; D018384:Oxidative Stress / Q000235:genetics; D011499:Protein Processing, Post-Translational / Q000235:genetics; D015398:Signal Transduction
chemical_list: D054477:Glutaredoxins; D008070:Lipopolysaccharides; D016328:NF-kappa B; D051549:Glutathione S-Transferase pi; D051550:I-kappa B Kinase
keywords: Asthma; GSTP; Inflammation; Lung; NF-κB; S-glutathionylation