The purpose of our study was to define a novel biased antagonist to protease-activated receptor-2 (PAR2) and elucidate its ability to prevent allergen-induced asthma in a humanized mouse model. Given that activation of the beta-arrestin signaling arm of PAR2 leads to characteristics of asthma, we hypothesized that an antagonist biased to this pathway would protect against allergen-induced asthma. We used xCELLigence real-time cellular analysis (RTCA), digital imaging calcium microscopy, and in-cell western (ICW) to evaluate Compound 937 (C937) antagonism of PAR2. We induced an acute asthma phenotype by intranasal application of the asthma-associated allergen Alternaria alternata (Alt) in a C57Bl/6 mouse strain that expresses both human and mouse PAR2 (PAR2hm mice). We evaluated the efficacy of C937 via intranasal, oropharyngeal, or oral gavage delivery using flexiVent to assay airway resistance and elastance and lung sections to evaluate inflammation and mucus production. We showed that C937 was a biased ligand PAR2 antagonist that selectively inhibits PAR2-dependent beta-arrestin/mitogen-activated protein kinase (MAPK) signaling with limited effect on PAR2-dependent Gq/calcium signaling. Intranasal co-application of C937 and Alt effectively limited acute allergen-induced airway hyperresponsiveness (AHR), but not airway inflammation or mucus overproduction. Oropharyngeal application or oral gavage of C937 followed by acute intranasal Alt challenge inhibited AHR with additional protection against airway inflammation and mucus overproduction. We conclude that C937 is an improved small-molecule biased PAR2 antagonist that effectively limits multiple allergen-induced asthma indicators in vivo. Further, oropharyngeal or oral administration of C937 provides an efficacious prophylactic treatment for allergen-induced asthma in humanized mice and thus represents a pharmacophore that can be optimized for clinical development for asthma and other PAR2-related allergic and inflammatory diseases. Funding sources: National Institutes of Health: AI140257, NS098826, HL160424, AI174540. HS and TL were Undergraduate Biology Research Program students. This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.
Plett et al. (Fri,) studied this question.