1,588 research outputs found

    Glutathione Peroxidase-1 Primes Pro-Inflammatory Cytokine Production after LPS Challenge In Vivo

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    Reactive oxygen species produced during the innate immune response to LPS are important agents of anti-pathogen defence but may also cause oxidative lung damage. Glutathione peroxidase-1 (gpx-1) is an anti-oxidant enzyme that may protect lungs from such damage. We assessed the in vivo importance of gpx-1 in LPS-induced lung inflammation. Male wild-type (WT) or gpx-1 deficient (gpx-1βˆ’/βˆ’) mice were treated intranasally with PBS or 10 Β΅g LPS and killed 3 and 24 h post LPS. Lungs were lavaged with PBS and then harvested for inflammatory marker expression. LPS caused an intense neutrophilia in WT BALF evident 3 and 24 h post challenge that was reduced in gpx-1βˆ’/βˆ’ mice. In addition, LPS-treated gpx-1βˆ’/βˆ’ mice had significantly fewer macrophages than LPS-treated WT mice. To understand the basis for this paradoxical reduction we assessed inflammatory cytokines and proteases at protein and transcript levels. MMP-9 expression and net gelatinase activity in BALF of gpx-1βˆ’/βˆ’ mice treated with LPS for 3 and 24 h was no different to that found in LPS-treated WT mice. BALF from LPS-treated gpx-1βˆ’/βˆ’ mice (3 h) had less TNF-Ξ±, MIP-2 and GM-CSF protein than LPS-treated WT mice. In contrast, LPS-induced increases in TNF-Ξ±, MIP-2 and GM-CSF mRNA expression in WT mice were similar to those observed in gpx-1βˆ’/βˆ’ mice. These attenuated protein levels were unexpectedly not mirrored by reduced mRNA transcripts but were associated with increased 20S proteasome expression. Thus, these data suggest that gpx-1 primes pro-inflammatory cytokine production after LPS challenge in vivo

    Apocynin and ebselen reduce influenza A virus-induced lung inflammation in cigarette smoke-exposed mice

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    Influenza A virus (IAV) infections are a common cause of acute exacerbations of chronic obstructive pulmonary disease (AECOPD). Oxidative stress is increased in COPD, IAV-induced lung inflammation and AECOPD. Therefore, we investigated whether targeting oxidative stress with the Nox2 oxidase inhibitors and ROS scavengers, apocynin and ebselen could ameliorate lung inflammation in a mouse model of AECOPD. Male BALB/c mice were exposed to cigarette smoke (CS) generated from 9 cigarettes per day for 4 days. On day 5, mice were infected with 1 Γ— 104.5 PFUs of the IAV Mem71 (H3N1). BALF inflammation, viral titers, superoxide production and whole lung cytokine, chemokine and protease mRNA expression were assessed 3 and 7 days post infection. IAV infection resulted in a greater increase in BALF inflammation in mice that had been exposed to CS compared to non-smoking mice. This increase in BALF inflammation in CS-exposed mice caused by IAV infection was associated with elevated gene expression of pro-inflammatory cytokines, chemokines and proteases, compared to CS alone mice. Apocynin and ebselen significantly reduced the exacerbated BALF inflammation and pro-inflammatory cytokine, chemokine and protease expression caused by IAV infection in CS mice. Targeting oxidative stress using apocynin and ebselen reduces IAV-induced lung inflammation in CS-exposed mice and may be therapeutically exploited to alleviate AECOPD

    What makes brands achieve iconic status?

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    We propose that brands do not achieve iconic status by chance. This article focuses on how brands manage iconic status effectively. Drawing on an exploratory study of iconic brands, we identify a brand's ability to inspire consumers and connect with them on a personal level as well as its visual identity and presence in consumers' mind as critical elements of brand status. Consumers' perceptions of a sample of brands were investigated through in-depth interviews, followed by the examination of these brands' activities through case-study analyses. The alignment between brand strategies and the relevant features highlighted by consumers was then assessed. A comprehensive framework for achieving iconicity is presented and discussed.Working Pape

    Innate cellular sources of interleukin-17A regulate macrophage accumulation in cigarette smoke-induced lung inflammation in mice

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    Cigarette smoke (CS) is the major cause of chronic obstructive pulmonary disease (COPD). Interleukin-17A (IL-17A) is a pivotal cytokine that regulates lung immunity and inflammation. The aim of this study was to investigate how IL-17A regulates CS-induced lung inflammation in vivo . IL-17A KO mice and neutralisation of IL-17A in WT mice reduced macrophage and neutrophil recruitment and CCL2, CCL3 and MMP-12 mRNA expression in response to acute CS exposure. IL-17A expression was increased in NOD SCID mice with non-functional B and T cells over a 4 week CS exposure period, where macrophages accumulated to the same extent as WT mice. Gene expression analysis by QPCR of isolated immune cell subsets detected increased levels of IL-17A transcript in macrophages, neutrophils and NK/NKT cells in the lungs of CS-exposed mice. In order to further explore the relative contribution of innate immune cellular sources, intracellular IL-17A staining was performed. Here, we demonstrate that CS exposure primes NK, NKT and Ξ³Ξ΄ T cells to produce more IL-17A protein and CS alone increased the frequency of IL17+ Ξ³Ξ΄ T cells in the lung, whereas IL-17A protein was not detected in macrophages and neutrophils. Our data suggest that activation of innate cellular sources of IL-17A is an essential mediator of macrophage accumulation in CS-exposed lungs. Targeting non-conventional T cell sources of IL-17A may offer an alternative strategy to reduce pathogenic macrophages in COPD

    A Longitudinal Study of Streptococcus mutans Colonization in Infants after Tooth Eruption

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    We previously reported that, before tooth eruption, over one-half of infants aged 6 mos were already infected with Streptococcus mutans. The aim of this investigation was to determine the colonization of S. mutans after tooth eruption in the same cohort of 111 infants (35 pre-term, 76 full-term). Our results showed that S. mutans colonization increased with increasing age, so that by 24 mos of age, 84% harbored the bacteria (p 10(5) CFU/mL (p < 0.02). In contrast, non-colonization of S. mutans was associated with toothbrushing (p < 0.03) and multiple courses of antibiotics (p < 0.001). Analysis of our data establishes the timing of S. mutans colonization in children from birth to 24 mos of age

    IL-17A and serum amyloid A are elevated in a cigarette smoke cessation model associated with the persistence of pigmented macrophages, neutrophils and activated NK cells

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    While global success in cessation advocacy has seen smoking rates fall in many developed countries, persistent lung inflammation in ex-smokers is an increasingly important clinical problem whose mechanistic basis remains poorly understood. In this study, candidate effector mechanisms were assessed in mice exposed to cigarette smoke (CS) for 4 months following cessation from long term CS exposure. BALF neutrophils, CD4+ and CD8+ T cells and lung innate NK cells remained significantly elevated following smoking cessation. Analysis of neutrophil mobilization markers showed a transition from acute mediators (MIP-2Ξ±, KC and G-CSF) to sustained drivers of neutrophil and macrophage recruitment and activation (IL-17A and Serum Amyoid A (SAA)). Follicle-like lymphoid aggregates formed with CS exposure and persisted with cessation, where they were in close anatomical proximity to pigmented macrophages, whose number actually increased 3-fold following CS cessation. This was associated with the elastolytic protease, MMP-12 (macrophage metallo-elastase) which remained significantly elevated post-cessation. Both GM-CSF and CSF-1 were significantly increased in the CS cessation group relative to the control group. In conclusion, we show that smoking cessation mediates a transition to accumulation of pigmented macrophages, which may contribute to the expanded macrophage population observed in COPD. These macrophages together with IL-17A, SAA and innate NK cells are identified here as candidate persistence determinants and, we suggest, may represent specific targets for therapies directed towards the amelioration of chronic airway inflammation

    Artificial mirtron-mediated gene knockdown:Functional DMPK silencing in mammalian cells

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    Mirtrons are introns that form pre-miRNA hairpins after splicing to produce RNA interference (RNAi) effectors distinct from Drosha-dependent intronic miRNAs. Here we present a design algorithm for artificial mirtrons and demonstrate, for the first time, efficient gene knockdown of myotonic dystrophy protein kinase (DMPK) target sequences in Renilla luciferase 3' UTR and subsequently pathogenic DMPK mRNA, causative of Type I myotonic dystrophy, using artificial mirtrons cloned as eGFP introns. Deep sequencing of artificial mirtrons suggests that functional mature transcripts corresponding to the designed sequence were produced in high abundance. They were further shown to be splicing-dependent, Drosha-independent, and partially dependent on exportin-5, resulting in the precise generation of pre-miRNAs. In a murine myoblast line containing a pathogenic copy of human DMPK with more than 500 CUG repeats, the DMPK artificial mirtron corrected DM1-associated splicing abnormalities of the Serca-1 mRNA, demonstrating the therapeutic potential of mirtron-mediated RNAi. Thus, further development and exploitation of the unique properties of mirtrons will benefit future research and therapeutic RNAi applications as an alternative to conventional RNAi strategies
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