Modulation of NF-κB and Hypoxia-Inducible Factor−1 byS-Nitrosoglutathione Does Not Alter Allergic Airway Inflammation in Mice

Abstract

Induction of nitric oxide synthase (NOS)-2 and production of nitric oxide (NO) are common features of allergic airway disease. Conditions of severe asthma are associated with deficiency of airway S-nitrosothiols, a biological product of NO that can suppress inflammation by S-nitrosylation of the proinflammatory transcription factor, NF-kB. Therefore, restoration of airway S-nitrosothiols might have therapeutic benefit, and this was tested in a mouse model of ovalbumin (OVA)-induced allergic inflammation. Naive or OVAsensitized animals were administered S-nitrosoglutathione (GSNO; 50 ml, 10 mM) intratracheally before OVA challenge and analyzed 48 hours later. GSNO administration enhanced lung tissue S-nitrosothiol levels and reduced NF-kB activity in OVA-challenged animals compared with control animals, but did not lead to significant changes in total bronchoalveolar lavage cell counts, differentials, or mucus metaplasia markers. Administration of GSNO also altered the activation of hypoxia-inducible factor (HIF)-1, leading to HIF-1 activation in naive mice, but suppressed HIF-1 activation in OVA-challenged mice. We assessed the contribution of endogenous NOS2 in regulating NF-kB and/or HIF-1 activation and allergic airway inflammation using NOS2 2/2 mice. Although OVA-induced NF-kB activation was slightly increased in NOS2 2/2 mice, associated with small increases in bronchoalveolar lavage neutrophils, other markers of allergic inflammation and HIF-1 activation were similar in NOS2 2/2 and wildtype mice. Collectively, our studies indicate that instillation of GSNO can suppress NF-kB activation during allergic airway inflammation, but does not significantly affect overall markers of inflammation or mucus metaplasia, thus potentially limiting its therapeutic potential due to effects on additional signaling pathways, such as HIF-1.Keywords: nitric oxide; asthma; S-nitrosothiols; nuclear factor-kB; hypoxia inducible factor21Nitric oxide (NO) is a ubiquitous signaling molecule that is continuously produced within the airways of healthy individuals, primarily originating from constitutive expression of the inducible NO synthase (NOS)-2 (iNOS) within the respiratory epithelium (1, 2). Airway NO production is increased under conditions of infection or inflammation due to induction of NOS2. Indeed, induction of airway NOS2 and increased airway production of NO are common symptoms of allergic asthma, an inflammatory disease of the airways characterized by airway hyperreactivity, smooth muscle thickening, and mucus hypersecretion. Analysis of exhaled human breath has demonstrated higher levels of NO in patients with asthma compared with healthy control subjects, with increases in epithelial NOS2 being the primary site of its production (1, 2). Induction of NOS2 is critical in innate antimicrobial or antiviral host defense, but its contribution in conditions of airway inflammation, including allergic asthma, is still controversial, and includes both pro-and anti-inflammatory properties, based on studies with NOS2 inhibitors...

NOS2 regulation of LPS-induced airway inflammation via S-nitrosylation of NF-κB p65

“…In addition, it appears that NOS2 may also function constitutively to maintain basal lung SNOprotein levels, since NOS2 Ϫ/Ϫ mice exhibited substantially lower SNO-p65 levels at baseline compared with WT controls (Fig. 5), which is consistent with recent findings by Olson et al (30). In this regard, we are currently attempting to elucidate the mechanisms responsible for basal airway/lung SNO maintenance and LPS-induced denitrosylation.…”

“…The results of the present study extend these observations to a mouse model of lung injury supporting an anti-inflammatory role for NOS2 in the lung via inhibition of NF-B. Of note, NOS2 deficiency was recently demonstrated to increase NF-B activity and modestly augment allergic airway inflammation in a mouse model of asthma, although mechanistic correlation to S-nitrosylation of p65 was equivocal (30).…”

S-nitrosoglutathione supplementation to ovalbumin-sensitized and -challenged mice ameliorates methacholine-induced bronchoconstriction

“…The uncoupling of airway inflammation and AHR in the OVA model with GSNO therapy is not entirely unexpected, since we previously found that GSNOR-deficient mice are protected from AHR and have elevated lung SNO content compared with WT control littermates despite no apparent changes in inflammation (32). In addition, a recent report by Olson et al (31) likewise did not support an anti-inflammatory role for GSNO in suppressing markers of inflammation or mucus metaplasia in an allergic airway model, even though the levels of active nuclear factor kappa b (NF-B), a target of S-nitrosylation (20,28), were reduced by GSNO in the lung. This discordance between proinflammatory cytokines and other markers of allergic inflammation may result from other compensatory effects of GSNO.…”

SCFJFK is a bona fide E3 ligase for ING4 and a potent promoter of the angiogenesis and metastasis of breast cancer

“…In order to explore the biological significance of JFK-mediated ING4 degradation, we analyzed the cellular signaling transduction pathways that are potentially influenced by JFK using the Human Signal Transduction PathwayFinder PCR array (SABioscience) (Hager-Theodorides et al 2009;Olson et al 2011). This array profiles the expression of ∼100 key genes representing 10 prominent cellular signal transduction pathways, including TGF-β, WNT, NF-κB, JAK/STAT, p53, Notch, Hedgehog, PPAR, oxidative stress, and hypoxia pathways.…”