Oxidative stress and cigarette smoke alter chromatin remodeling but differentially regulate NF‐κB activation and proinflammatory cytokine release in alveolar epithelial cells

Moodie, Fiona M.; Marwick, John A.; Anderson, Charlotte S.; Szulakowski, Patryk; Biswas, Saibal K; Bauter, Mark R.; Kilty, Iain; Rahman, Irfan

doi:10.1096/fj.04-1506fje

Cited by 292 publications

(257 citation statements)

References 56 publications

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“…Because D-NAC and non-thiol antioxidants like trolox did not block p65-NFB DNA binding (data not shown), the results indicated that the NAC-mediated effect on p65-NFB was GSH-dependent. These results were also in agreement with recent reports showing that NAC and increased GSH down-regulate cigarette smoke-and tumor necrosis factor-induced NFB activation in A549 alveolar epithelial, U937 human histiocytic lymphoma, HeLa human epithelial, and MCF-7 human breast cancer cells (37,38). Our results also indicate that the NFB pathway is crucial in protecting MIA PaCa-2 cells from hypoxia-induced cell death, as confirmed by the pro-apoptotic effect of the NFB inhibitor (Fig.…”

Section: Discussionsupporting

confidence: 93%

Glutathione Supplementation Potentiates Hypoxic Apoptosis by S-Glutathionylation of p65-NFκB

Qanungo

Starke

Pai

et al. 2007

Journal of Biological Chemistry

151

128

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In murine embryonic fibroblasts, N-acetyl-L-cysteine (NAC), a GSH generating agent, enhances hypoxic apoptosis by blocking the NFB survival pathway (Qanungo, S., Wang, M., and Nieminen, A. L. (2004) J. Biol. Chem. 279, 50455-50464). Here, we examined sulfhydryl modifications of the p65 subunit of NFB that are responsible for NFB inactivation. In MIA PaCa-2 pancreatic cancer cells, hypoxia increased p65-NFB DNA binding and NFB transactivation by 2.6-and 2.8-fold, respectively. NAC blocked these events without having an effect on p65-NFB protein levels and p65-NFB nuclear translocation during hypoxia. Pharmacological inhibition of the NFB pathway also induced hypoxic apoptosis, indicating that the NFB signaling pathway is a major protective mechanism against hypoxic apoptosis. In cell lysates after hypoxia and treatment with N-ethylmaleimide (thiol alkylating agent), dithiothreitol (disulfide reducing agent) was not able to increase binding of p65-NFB to DNA, suggesting that most sulfhydryls in p65-NFB protein were in reduced and activated forms after hypoxia, thereby being blocked by N-ethylmaleimide. In contrast, with hypoxic cells that were also treated with NAC, dithiothreitol increased p65-NFB DNA binding. Glutaredoxin (GRx), which specifically catalyzes reduction of protein-SSG mixed disulfides, reversed inhibition of p65-NFB DNA binding in extracts from cells treated with hypoxia plus NAC and restored NFB activity. This finding indicated that p65-NFB-SSG was formed in situ under hypoxia plus NAC conditions. In cells, knock-down of endogenous GRx1, which also promotes protein glutathionylation under hypoxic radical generating conditions, prevented NAC-induced NFB inactivation and hypoxic apoptosis. The results indicate that GRx-dependent S-glutathionylation of p65-NFB is most likely responsible for NAC-mediated NFB inactivation and enhanced hypoxic apoptosis.Tumor hypoxia is strongly associated with tumor propagation, malignant progression, and resistance to chemo-and radiation therapy (1). NFB 2 is a redox-regulated transcription factor that is activated during hypoxia (2, 3). NFB belongs to the Rel family, which includes five mammalian Rel/NFB proteins: RelA (p65), c-Rel, RelB, NFB1 (p50/p105), and NFB2 (p52/ p100) (4). The inactive form of NFB is localized in the cytoplasm as p65:p50 (the most abundant form) or p50:cRel heterodimers through interaction with IB repressor proteins (IB␣, IB␤, IB␥, and IB⑀) (5). Once activated, NFB translocates to the nucleus, where it binds to DNA and activates various target genes including Bcl-xL, Bcl-2, a hematopoieticspecific Bcl-2 homologue A1, caspase-8-FADD-like interleukin-1␤-converting enzyme inhibitory protein, tumor necrosis factor receptor-associated factors 1 and 2, cellular inhibitors of apoptosis, and X chromosome-linked inhibitor of apoptosis (XIAP/hILP) (6, 7).NFB family proteins have a conserved domain of ϳ300 amino acids in the amino-terminal region known as the Rel homology region. The Rel homology region consists of a DNA binding domain, a dimerization d...

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Section: Discussionsupporting

confidence: 93%

Glutathione Supplementation Potentiates Hypoxic Apoptosis by S-Glutathionylation of p65-NFκB

Qanungo

Starke

Pai

et al. 2007

Journal of Biological Chemistry

151

128

View full text Add to dashboard Cite

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“…The concentration of the complexes that caused 50% inhibition of the growth (IC 50) was determined by using the sulforhodamine-B (SRB) assay (39) as reported (13). For IC 50 determinations on A549 cells with increased thiol levels, cells were preincubated with 5 mM N-acetylcysteine for 2 h, a concentration and time previously reported to be nontoxic for this cell line (40), and confirmed by our controls. The N-acetylcysteine was removed, cells were washed twice in PBS, fresh cell medium was added, and IC 50 values were then determined.…”

Section: Ic 50supporting

confidence: 52%

Catalytic organometallic anticancer complexes

Dougan

Habtemariam

McHale

et al. 2008

Proc. Natl. Acad. Sci. U.S.A.

281

296

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Organometallic complexes offer chemistry that is not accessible to purely organic molecules and, hence, potentially new mechanisms of drug action. We show here that the presence of both an iodido ligand and a -donor/ -acceptor phenylazopyridine ligand confers remarkable inertness toward ligand substitution on the half-sandwich ''piano-stool'' ruthenium arene complexes [( 6 -arene)Ru(azpy)I] ؉ (where arene ‫؍‬ p-cymene or biphenyl, and azpy ‫؍‬ N,Ndimethylphenyl-or hydroxyphenyl-azopyridine) in aqueous solution. Surprisingly, despite this inertness, these complexes are highly cytotoxic to human ovarian A2780 and human lung A549 cancer cells. Fluorescence-trapping experiments in A549 cells suggest that the cytotoxicity arises from an increase in reactive oxygen species. Redox activity of these azopyridine Ru II complexes was confirmed by electrochemical measurements. The first one-electron reduction step (half-wave potential ؊0.2 to ؊0.4 V) is assignable to reduction of the azo group of the ligand. In contrast, the unbound azopyridine ligands are not readily reduced. Intriguingly the ruthenium complex acted as a catalyst in reactions with the tripeptide glutathione (␥-L-Glu-L-Cys-Gly), a strong reducing agent present in cells at millimolar concentrations; millimolar amounts of glutathione were oxidized to glutathione disulfide in the presence of micromolar ruthenium concentrations. A redox cycle involving glutathione attack on the azo bond of coordinated azopyridine is proposed. Such ligand-based redox reactions provide new concepts for the design of catalytic drugs.arenes ͉ cytotoxicity ͉ glutathione ͉ redox reactions ͉ ruthenium complexes O rganometallic complexes offer potential for the development of new materials with a wide range of applications (1, 2). Organometallic complexes can exhibit chemical reactivity not possessed by either the metal or organic ligands alone and this reactivity can be fine-tuned by subtle changes in the electronic and steric properties of the bound ligands, or by variation of the metal and its oxidation state. These features provide a versatile platform for drug design that is now being exploited in several areas. For example, the redox activity of the organometallic ferrocenylphenol substitutents enhances the anticancer activity of tamoxifen derivatives by conferring an ability to generate reactive oxygen species in cells (3). Here we consider the anticancer activity of ruthenium(II) arene complexes. Such complexes are well known as catalysts in industry, for example, for hydrogenation reactions (4). Although organometallic complexes can catalyze hydrogenation of intracellular biomolecules (5), metal-centered catalysts might be readily poisoned and be ineffective in biological media.Organometallic half-sandwich Ru II arenes of the type [( 6 -arene)Ru(YZ)(X)] ϩ where YZ is typically a chelating diamine ligand (e.g., ethylenediamine, en) and X is a halide (e.g., Cl) exhibit anticancer activity in vitro and in vivo (6, 7). As with many metal-based anticancer drugs, the primary cellula...

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“…To further explore the dysregulation of inflammatory response in KO mice, modifications of the cell signaling pathway in the lungs were examined. In particular, we found NF-B, a major transcription factor for cytokine production in alveolar epithelial cells, to be highly activated (61).…”

Section: Discussionmentioning

confidence: 83%

Elevated Inflammatory Response in Caveolin-1-deficient Mice with Pseudomonas aeruginosa Infection Is Mediated by STAT3 Protein and Nuclear Factor κB (NF-κB)

Yuan

Huang

Fox

et al. 2011

Journal of Biological Chemistry

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Caveolin-1 (Cav-1), an important composition protein within the flask-shaped membrane invaginations termed caveolae, may play a role in host defense against infections. However, the phenotype in Pseudomonas aeruginosa-infected cav1 knock-out (KO) mice is still unresolved, and the mechanism involved is almost entirely unknown. Using a respiratory infection model, we confirmed a crucial role played by Cav-1 in host defense against this pathogen because Cav-1 KO mice showed increased mortality, severe lung injury, and systemic dissemination as compared with wild-type (WT) littermates. In addition, cav1 KO mice exhibited elevated inflammatory cytokines (IL-6, TNF-␣, and IL-12a), decreased phagocytic ability of macrophages, and increased superoxide release in the lung, liver, and kidney. We further studied relevant cellular signaling processes and found that STAT3 and NF-B are markedly activated. Our data revealed that the Cav-1/STAT3/NF-B axis is responsible for a dysregulated cytokine response, which contributes to increased mortality and disease progression. Moreover, downregulating Cav-1 in cell culture with a dominant negative strategy demonstrated that STAT3 activation was essential for the translocation of NF-B into the nucleus, confirming the observations from cav1 KO mice. Collectively, our studies indicate that Cav-1 is critical for inflammatory responses regulating the STAT3/NF-B pathway and thereby impacting P. aeruginosa infection.Pseudomonas aeruginosa accounts for 25% of Gram-negative bacteria isolated from hospitals and is associated with high morbidity and mortality (1). P. aeruginosa frequently infects immunocompromised individuals, such as those affected by ventilator-associated infection, severe burns, and cancer (2). More than 80% of cystic fibrosis patients suffer severe P. aeruginosa infection (3). This bacterium becomes increasingly resistant to various antibiotics. Further understanding the mechanism of the host-pathogen interaction may result in effective approaches to preventing this infection. Thus, P. aeruginosa has been a focus of airway infectious diseases (1, 4 -6).Recent studies suggest that P. aeruginosa also invades the lung epithelial cells through lipid raft-mediated endocytosis (7-9), which is a possible reason why this bacterium develops such formidable resistance to antibiotics (10). The invasion process of P. aeruginosa may involve certain lipid raft-associated proteins, including the caveolin family of proteins (9). Using caveolin-1 (cav1) 3 KO mice, two recent studies investigated the role of Cav-1 during P. aeruginosa infection (11, 12); however, their observations were very different. Thus, the role of Cav-1 in this infection needs to be clearly characterized.Caveolins are a family of integral membrane proteins involved in caveola formation and receptor-dependent endocytosis (13-15). Cav-1 and -2 are co-expressed in various cells, such as endothelial cells, airway epithelial cells, and type I pneumocytes. Cav-1 is the major component of caveolae, flaskshaped plasma membran...

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Oxidative stress and cigarette smoke alter chromatin remodeling but differentially regulate NF‐κB activation and proinflammatory cytokine release in alveolar epithelial cells

Cited by 292 publications

References 56 publications

Glutathione Supplementation Potentiates Hypoxic Apoptosis by S-Glutathionylation of p65-NFκB

Glutathione Supplementation Potentiates Hypoxic Apoptosis by S-Glutathionylation of p65-NFκB

Catalytic organometallic anticancer complexes

Elevated Inflammatory Response in Caveolin-1-deficient Mice with Pseudomonas aeruginosa Infection Is Mediated by STAT3 Protein and Nuclear Factor κB (NF-κB)

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