D21-10 Isoform-specific Function of Gasdermin B Isoform 3 in Airway Inflammation and Hyperresponsiveness in Asthma

Rationale The Gasdermin B (GSDMB) gene is strongly associated with asthma susceptibility, particularly in childhood-onset forms of the disease. GSDMB genetic variants can influence airway inflammation and immune responses that increase disease risk and severity. Transgenic mouse models expressing human GSDMB have been developed, yet the functional contributions of different GSDMB isoforms remain unclear. To elucidate the role of GSDMB isoform 3 (GSDMB-3) in allergic asthma, we investigated both ubiquitous (hGSDMB-3Zp3-cre) and bronchial epithelium-specific (hGSDMB-3CC10-cre) transgenic mice in an established house dust mite (HDM)-induced asthma model. Methods RNA isolated from bronchial epithelial samples from 26 asthmatic patients and 17 healthy controls was analyzed using Illumina Human HT12 expression microarray to quantify GSDMB isoform expression. Human GSDMB-3 knock-in mice (Biocytogen, MA) were crossed with Zp3-cre or CC10-cre mice (Jackson Laboratory, ME) to generate hGSDMB-3Zp3-cre or hGSDMB-3CC10-cre strains on a C57BL/6 background. At six weeks of age, mice received intranasal house dust mite or saline challenges on day 0, 7, 14, and 21 to induce allergic asthma. On day 24, animals were sacrificed for assessments of: (i) bronchoalveolar-lavage fluid (BALF) immune cell populations by flow cytometry, (ii) plasma IgE and BALF cytokines levels by ELISA, (iii) lung gene expression by qPCR, (iv) lung histology, and (v) airway physiology and hyperresponsiveness using FlexiVent. Results GSDMB-3 was the most abundant and most differentially expressed GSDMB isoform in asthmatic airways (vs. non-asthmatic airways). In naïve hGSDMB-3Zp3-cre and hGSDMB-3CC10-cre mice, GSDMB-3 overexpression did not alter baseline phenotypes relative to Cre-only controls. Following HDM challenge, ubiquitous GSDMB-3 overexpression (hGSDMB-3Zp3-cre) increased airway hyperresponsiveness and markedly enhanced eosinophil and T helper cells accumulation, along with elevated BALF IL-5 and plasma IgE levels, indicating amplification of type 2 inflammation. In contrast, bronchial-specific GSDMB-3 overexpression (hGSDMB-3CC10-cre) promoted neutrophil and interstitial macrophage recruitment and IL-6 release, without augmenting Th2 inflammation. Conclusion Our findings demonstrate that GSDMB-3 overexpression contributes to asthma pathogenesis through multiple mechanisms. Epithelial GSDMB-3 appears to play a dual role in acute and chronic airway inflammation during allergen exposure or pathogen infection, while immune cell-expressed GSDMB-3 enhances type 2 inflammation and airway hyperresponsiveness, thereby exacerbating disease severity. This study provides the first detailed functional characterization of GSDMB isoform 3 in asthma, offering new insights into its cell type-specific roles and potential as a therapeutic target. This abstract is funded by: NIH/NIHBI 5R01HL123546