The most widely used treatments for asthma consist of bronchodilators and inhaled corticosteroids. Although majority of asthmatics achieve control with some combination of these medications, there are those who receive no benefit from these treatments1 and for whom few alternative treatments remain. This indicates the need for the development of novel asthma therapies. Despite the numerous biologic agents developed which are targeted for the treatment of asthma, few have translated into the clinic (leukotriene modifiers2, 3 and anti- IgE4, 5). This disparity between what therapies are found to be efficacious in preclinical models and those which are actually beneficial in asthmatics, might be explained by the stage in the allergic asthmatic response being targeted by the therapy. A number of these biologicals such as anti-IL-46, 7, anti-IL-58, and anti-IL-139, 10 therapy, are directed at molecules which are generated late in the allergic reaction. By studying events which occur during the initiation of an allergic response, we might better understand and be able to manipulate immune responses for clinical gain. In spite of our knowledge of the downstream allergic and asthmatic sequelae (release of cytokines and inflammatory mediators leading to mucus overproduction, airway hyperreactivity, subepithelial fibrosis etc), little is known about which receptors and signaling pathways are important in initiating an allergic response. Nucleotide Oligomerization Domain 2 (NOD2) is an innate immune receptor for peptidoglycan11-13 which has also recently been implicated in the development of type-2 responses14-16. When such responses are dysregulated, they can promote the development of allergic and asthmatic disease. RIP2 is a kinase which is essential for transducing signals emanating from NOD217, 18. By determining the role which RIP2 plays during the initial response to allergens and identifying novel mechanisms by which RIP2 activity is influenced, one can ascertain if inhibition of RIP2 may be efficacious for the treatment of allergic asthma. The current proposal seeks to determine if RIP2 activation occurs downstream of allergen exposure through the use of genetic and biochemical RIP2 activation markers. We will also explore a novel mechanism by which RIP2 can potentially be activated (NOD independent) and how this may contribute to the pathogenesis of asthma. Lastly, by utilizing a novel setting of RIP2 overactivation (the Itchy mouse) and novel RIP2 inhibitors, we will determine the efficacy of RIP2 inhibition in animal models of asthma.
Attainment of the goals outlined within this proposal will have verified the involvement of RIP2 in the pathogenesis of asthma and will have determined the efficacy of using novel RIP2 inhibitors in preclinical models of asthma. The genetic and biochemical RIP2 activation markers established in this study, in combination with the novel RIP2 inhibitors, may be used in future studies evaluating the potential of using such RIP2 activation markers as predictive biomarkers for personalized treatment in asthma.
|Tigno-Aranjuez, Justine T; Benderitter, Pascal; Rombouts, Frederik et al. (2014) In vivo inhibition of RIPK2 kinase alleviates inflammatory disease. J Biol Chem 289:29651-64|