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A5804 - Substrate Selective Targeting of ERK Signaling Mitigates Allergen-Induced Asthma Features in Mice
Author Block: A. P. Nayak1, R. Yi1, N. Wang1, S. D. Shah1, P. Shapiro2, D. A. Deshpande1; 1Department of Medicine, Thomas Jefferson University, Philadelphia, PA, United States, 2Department of Pharmaceutical Sciences, University of Maryland, Baltimore, MD, United States.
Rationale: ERK-mediated signaling is ubiquitous in a variety of cell types (resident and inflammatory) and regulates activity of various transcription factors that contribute to the overall pathophysiology of asthma including mucus secretion and remodeling. Broadly targeting ERK is challenging since its activity is crucial for normal cellular functions. Using an innovative approach, we have identified candidate small molecule inhibitors with benzenesulfonate scaffold that selectively inhibits ERK-mediated activity of a limited number of substrates (e.g. adaptor protein (AP)-1). In this study, we describe the findings of therapeutic targeting of ERK-mediated substrate specific signaling with compound SF-3-030 in a murine model of allergen (house dust mite/HDM) induced asthma.
Methods: Allergic asthma was established in Balb/cJ mice (8-10 weeks old) by repeated intranasal instillation of HDM allergen (25 μg/35 μl) for 3 weeks (5 days a week). A subgroup of mice was prophylactically dosed with either low (5 mg/kg) or high dose (10 mg/kg) of the small molecule substrate specific inhibitor (SF-3-030) of ERK signaling via intranasal route 30 mins prior to allergen challenge. Following conclusion of the dosing schedule, mice were subjected to flexiVent for assessing pulmonary mechanics, processed for determining cellularity in bronchoalveolar lavage and for histopathological analysis of the lung tissue.
Results: Repeated intranasal administration of HDM established asthma phenotype in mice, with marked increase in airway eosinophilia and development of airway hyperresponsiveness (AHR). Treatment with high dose of SF-3-030 significantly dampened overall airway inflammation and curtailed the recruitment of eosinophils, monocytes and lymphocytes to the airways. Histopathological analysis of lung tissue revealed contracted pleocellular peribronchiolar and perivascular inflammation in SF-3-030 treated animals. Analysis of lung tissue also revealed reduced goblet cell metaplasia and mucus production in the bronchioles. Most importantly, treatment with SF-3-030 resulted in significant reduction in collagen deposition in the lung, indicating protection from airway remodeling. Finally, mice treated with the high dose of SF-3-030 demonstrated lower airway resistance on challenge with increasing doses of methacholine and consequently were protected from development of AHR.
Conclusion: These findings demonstrate that specifically targeting selective substrates activated by ERK signaling alleviates the allergen-induced inflammation, mucus secretion, remodeling and AHR in a murine model. Collectively, our pre-clinical data underline the translational potential of developing substrate specific small molecule inhibitors of ERK signaling for treatment of asthma.