Targeting the networks that underpin contiguous immunity in asthma and chronic obstructive pulmonary disease.

Academic Unit of Respiratory Medicine, School of Medicine and Biomedical Sciences, University of Sheffield, L Floor, Royal Hallamshire Hospital, Sheffield, UK.
American Journal of Respiratory and Critical Care Medicine (Impact Factor: 11.99). 03/2007; 175(4):306-11. DOI: 10.1164/rccm.200606-777PP
Source: PubMed

ABSTRACT Recent advances in the field of innate immunity have driven an important reappraisal of the role of these processes in airway disease. Various strands of evidence indicate that resident cells, such as macrophages and epithelial cells, have central importance in the initiation of inflammation. Macrophage activation has the potential to regulate not just typical aspects of innate immunity but also, via a variety of intricate cell-cell networks, adaptive responses and responses characterized by Th2-type cytokine production. In turn, such adaptive immune processes modify the phenotype and function of the innate immune system. Cooperative responses between monocytic cells and tissue cells are likely to be crucial to the generation of effective inflammatory responses, and a realization of the importance of these networks is providing a new way of identifying antiinflammatory therapies. Importantly, the repeated cycles of allergic and nonallergic inflammation that comprise chronic human airway disease are not necessarily well described by current terminology, and we propose and describe a concept of contiguous immunity, in which continual bidirectional cross-talk between innate and adaptive immunity describes disease processes more accurately.

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Human rhinoviruses (HRV) have been linked to the development of childhood asthma and recurrent acute asthma exacerbations throughout life, and contribute considerably to the healthcare and economic burden of this disease. However, the ability of HRV infections to trigger exacerbations, and the link between allergic status and HRV responsiveness, remains incompletely understood. Whilst the receptors on human airway cells that detect and are utilized by most HRV group A and B, but not C serotypes are known, how endosomal pattern recognition receptors (PRRs) detect HRV replication products that are generated within the cytoplasm remains somewhat of an enigma. In this article, we explore a role for autophagy, a cellular homeostatic process that allows the cell to encapsulate its own cytosolic constituents, as the crucial mechanism controlling this process and regulating the innate immune response of airway epithelial cells to viral infection. We will also briefly describe some of the recent insights into the immune responses of the airway to HRV, focusing on neutrophilic inflammation that is a potentially unwanted feature of the acute response to viral infection, and the roles of IL-1 and Pellinos in the regulation of responses to HRV.
    Clinical & Experimental Allergy 01/2014; 44(1):20-8. DOI:10.1111/cea.12182 · 4.32 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: PurposeTo investigate the effects of icariin, a major constituent of flavonoids isolated from the herb Epimedium, on cigarette smoke (CS) induced inflammatory responses in vivo and in vitro.MethodsIn vivo, BALB/c mice were exposed to smoke of 15 cigarettes for 1 h/day, 6 days/week for 3 months and dosed with icariin (25, 50 and 100 mg/kg) or dexamethasone (1 mg/kg). In vitro, A549 cells were incubated with icariin (10, 50 and 100 µM) followed by treatments with CSE (2.5%).ResultsWe found that icariin significantly protected pulmonary function and attenuated CS-induced inflammatory response by decreasing inflammatory cells and production of TNF-α, IL-8 and MMP-9 in both the serum and BALF of CS-exposed mice and decreasing production of TNF-α and IL-8 in the supernatant of CSE-exposed A549 cells. Icariin also showed properties in inhibiting the phosphorylation of NF-κB p65 protein and blocking the degradation of IΚB-α protein. Further studies revealed that icariin administration markedly restore CS-reduced GR protein and mRNA expression, which might subsequently contribute to the attenuation of CS-induced respiratory inflammatory response.ConclusionTogether these results suggest that icariin has anti-inflammatory effects in cigarette smoke induced inflammatory models in vivo and in vitro, possibly achieved by suppressing NF-κB activation and modulating GR protein expression.
    PLoS ONE 08/2014; 9(8):e102345. DOI:10.1371/journal.pone.0102345 · 3.53 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: High levels of ambient environmental particulate matter (PM10 i.e. <10 μm median aerodynamic diameter) have been linked to acute exacerbations of asthma. We examined the effects of delivering a single dose of Sydney PM10 by intranasal instillation to BALB/c mice that had been sensitised to ovalbumin and repeatedly challenged with a low (≈3 mg/m3) mass concentration of aerosolised ovalbumin for 4 weeks. Responses were compared to animals administered carbon black as a negative control, or a moderate (≈30 mg/m3) concentration of ovalbumin to simulate an allergen-induced acute exacerbation of airway inflammation. Delivery of PM10 to mice, in which experimental mild chronic asthma had previously been established, elicited characteristic features of enhanced allergic inflammation of the airways, including eosinophil and neutrophil recruitment, similar to that in the allergen-induced exacerbation. In parallel, there was increased expression of mRNA for interleukin (IL)-33 in airway tissues and an increased concentration of IL-33 in bronchoalveolar lavage fluid. Administration of a monoclonal neutralising anti-mouse IL-33 antibody prior to delivery of particulates significantly suppressed the inflammatory response induced by Sydney PM10, as well as the levels of associated pro-inflammatory cytokines in lavage fluid. We conclude that IL-33 plays a key role in driving airway inflammation in this novel experimental model of an acute exacerbation of chronic allergic asthma induced by exposure to PM10.
    Clinical & Experimental Immunology 04/2014; 177(2). DOI:10.1111/cei.12348 · 3.28 Impact Factor