https://www.atsjournals.org/doi/pdf/10.1164/ajrccm-conference.2024.209.1_MeetingAbstracts.A6985
D21 TERMINATOR: CONTROL OF AIRWAY INFLAMMATION AND IMMUNE RESPONSE IN ASTHMA / Poster Discussion Session / Wednesday, May 22/08:15 AM-10:15 AM / San Diego Convention Center, Room 31A-C (Upper Level)
M. Mikami, A. Kanaya, K. Dantzler, J. Perez-Zoghbi, C. W. Emala
Rationale: Allergic asthma is a chronic inflammatory respiratory disease and is the most common asthma phenotype in both children and adults. Among cell types that contribute to allergic asthma symptoms, mast cells play a major role by triggering bronchoconstriction and recruiting other immune cells through the release of mediators. In addition to its role in the airways of asthma patients, mast cells in the brain may be contributing to behavioral changes that we observed in a murine model of chronic allergic lung inflammation using house dust mite antigen. We previously reported that a phosphatidylinositol 4,5-bisphostae (PIP2 )-binding peptide fragment of the actin[1]binding protein gelsolin, attenuated murine and human airway contractions ex vivo, possibly by modulating G protein-coupled receptor-mediated calcium release from the sarcoplasmic reticulum. We utilized this PIP2 -binding peptide to test our hypothesis that mast cell calcium signaling and functions can also be modulated. Methods: Studies were approved by the Columbia University IACUC. The ten amino acid sequence of the gelsolin peptide (QRLFQVKGRR) and a control peptide (QRL) were synthesized and conjugated with rhodamine B by Biomatik (Wilmington, DE). GCaMP 6 mice were injected (i.p.) with ovalbumin at 4, 2 and 1 week before harvesting intraperitoneal cells enriched with mast cells. Harvested mast cells were incubated overnight on a coverslip in media containing DNP-IgE. Peritoneal mast cells were identified by staining with an anti-CD117 antibody and their calcium signaling (+/- gelsolin peptide) were measured after perfusing with DNP-containing buffer. Precision-cut lung slices were made from the same GCaMP 6 mice to measure airway smooth muscle cell calcium oscillations +/- pretreatment with the gelsolin peptide. Mast cell degranulation was measured +/- the gelsolin peptide using the RBL-2H3 cell line. Results: The gelsolin peptide decreased IgE-mediated degranulation of RBL-2H3 mast cells and attenuated IgE-mediated calcium oscillations in peritoneal mast cells. The gelsolin peptide also inhibited the frequency of methacholine-induced calcium oscillations in airway smooth muscle within precision cut lung slices of GCaMP 6 mice. Conclusions: The gelsolin peptide, corresponding to the PIP2 binding region, attenuated calcium oscillations in airway smooth muscle. The peptide also reduced IgE-mediated mast cell degranulation in vitro and mast cell calcium oscillations ex vivo. Therefore, this small peptide fragment of the actin-regulatory protein gelsolin, may be a therapeutic option in allergic bronchoconstrictive diseases by not only preventing bronchoconstriction but also by modulating mast cell functions that play a critical role in allergen-induced lung inflammation.
Mastopedia Research Feed 