5-HT2 receptor activation alleviates airway inflammation and structural remodeling in a chronic mouse asthma model

Thomas W. Flanagan, LSU Health Sciences Center - New Orleans
Melaine N. Sebastian, LSU Health Sciences Center - New Orleans
Diana M. Battaglia, LSU Health Sciences Center - New Orleans
Timothy P. Foster, LSU Health Sciences Center - New Orleans
Stephania A. Cormier, Louisiana State University
Charles D. Nichols, LSU Health Sciences Center - New Orleans

Abstract

© 2019 Aims: Although the bulk of research into the biology of serotonin 5-HT2A receptors has focused on its role in the CNS, selective activation of these receptors in peripheral tissues can produce profound anti-inflammatory effects. We previously demonstrated that the small molecule 5-HT2 receptor agonist (R)-2,5-dimethoxy-4-iodoamphetamine [(R)-DOI] inhibits TNF-α-mediated proinflammatory signaling cascades and inflammation via 5-HT2A receptor activation and prevents the development of, and inflammation associated with, acute allergic asthma in a mouse ovalbumin (OVA) model. Here, we investigated the ability of (R)-DOI to reverse inflammation and symptoms associated with established asthma in a newly developed model of chronic asthma. Methods: An 18-week ovalbumin challenge period was performed to generate persistent, chronic asthma in BALB/c mice. Four once daily intranasal treatments of (R)-DOI were administered one week after allergen cessation, with respiratory parameters being measured by whole-body plethysmography (WBP). Cytokine and chemokine levels were measured by quantitative real-time polymerase chain reaction (qRT-PCR) in homogenized lung tissue, bronchoalveolar (BALF) fluid was analyzed for chemokine modulation by multiplex assays, and Periodic Acid-Schiff and Masson's Trichrome staining was performed to determine goblet cell infiltration and overall changes to lung morphology. Key findings: 5-HT2 activation via (R)-DOI attenuates elevated airway hyperresponsiveness to methacholine, reduces pulmonary inflammation and mucus production, and reduces airway structural remodeling and collagen deposition by nearly 70%. Significance: Overall, these data provide support for the therapeutic potential of (R)- DOI and 5-HT2 receptor activation for the treatment of asthma, and identifies (R)- DOI as a novel therapeutic compound against pulmonary fibrosis.