Amelioration of rhinovirus induced asthma exacerbations by serpin B1

PROJECT SUMMARY Asthma exacerbations are a major cause of ER visits and hospitalizations with annual direct costs of approximately $billionyear in the USAViral infectionsin particular rhinoviralRVinfectionsare a major precipitant of asthma exacerbations in allergic asthmaticsAs there are overRV serotypes andfor nowno RV vaccinenovel strategies to inhibit RV induced airway inflammation are needed to prevent asthma exacerbations associated with increased airway hyper reactivityAHRState of the art research recently demonstrated that RV infection in allergic humans and mice can induce neutrophils to undergo NETosisa newly recognized inflammatory process involving the expulsion of Neutrophil Extracellular TrapsNETandapos scomprising linearized double strandedds DNA bearing cytotoxic histones and granule proteins such as myeloperoxidase and elastaseFurthermoreNETandapos s can be sensed by the innate or adaptive immune system to boost typeimmunity and enhance the severity of asthma exacerbationsDegradation of NETs by DNase or inhibition of elastase by alphaantitrypsinAAThave both proven effective at preventing allergic asthma exacerbations in animal models but neither is a direct inhibitor of NETosisSerpin BsBis a protein both structurally and functionally related to AATboth inhibit the neutrophil serine proteinasesNSPandapos selastasecathepsin G and proteinaseimplicated in inflammation and airway hyper reactivityAHRthat is abundantly produced inside monocytes and neutrophils but unlike AAT directly blocks NETosis and regulates the expansion of Thcytokine producing cells in vitroHoweverSerplus Technology LLC has recently shown that human and mouse sB andapos s are subject to inactivation by reactive oxygen speciesROSthat convert the protein into an elastase substrateTo prevent this inactivation we have created an oxidation resistant sBOxR sBthat retains elastase inhibitory activity in the presence of ROS and hypothesize that it will be an effective in vivo inhibitor of both elastase and NETosis during inflammatory episodes and will block RV induced NETosis thus diminishing Thmediated T cell responses to more effectively control allergic asthma exacerbationsWe will test if OxR sBcan prevent RV induced airway inflammation and AHR in house dust mite sensitized mice andif successfulundertake further preclinical and clinical development such that it may improve control of RV induced asthma exacerbations in allergic asthmaticsThe proposed research in phase I will focus onAimthe purification and biochemical characterization of oxidation resistant mouse sb a andAimproviding proof of principle in an animal model of RV induced asthmaThe outcome of these studies will guide the design of future efficacy studies in animals and humans PROJECT NARRATIVE Viral infectionsin particular rhinoviralRVinfectionsare a major precipitant of asthma exacerbations in allergic asthmatics and as there are overRV serotypes and no RV vaccine as yetnovel strategies to inhibit the RV induced airway inflammation and increased airway hyperreactivityAHRare urgently requiredSerpin Bis an endogenous regulator of neutrophil protease activity and Neutrophil Extracellular TrapNETformationkey inflammatory processes important for induction of exacerbations in asthmatic humans and miceWe have discovered that sBis subject to inactivation by reactive oxygen speciesROSand have made an ROS resistant form of sBwhich we seek to prove can function in the asthmatic lung as an effective inhibitor of inflammatory proteasescytokine productionand NETosis to ameliorate airway inflammation and reduce AHR thus offering an additional therapeutic candidate to prevent or treat the underlying pathology of asthma exacerbations