A Single-cell Transcriptomic Profiling Reveals the Effects of Chronic House Dust Mite Exposure on the Murine Lung Microenvironment

House dust mite (HDM) is a common environmental aeroallergen linked to the development of allergic airway inflammation and asthma. While the effects of acute HDM exposure on T helper 2 (Th2)-driven allergic responses and pulmonary eosinophilia are well established in murine models, the impact of chronic HDM exposure on other inflammatory responses, particularly those involving interleukin-1ß (IL-1ß) and neutrophilia, remains poorly defined. To address this gap, we performed single-cell RNA sequencing (scRNA-seq) to examine lung immune responses in wild-type and IL-1ß-deficient mice following chronic HDM exposure. Our data reveal that HDM promotes the recruitment of diverse immune cell populations in the lungs, including neutrophils, alternatively activated (M2-polarized) macrophages, B-2 (follicular) B cells, and multiple CD4 regulatory and effector T cell subsets. IL-1ß signaling was essential for supporting neutrophil and Th17 responses, whereas its absence enhanced Th2-skewed immune polarization in the lung. These immune populations differently contribute to the development or resolution of lung inflammation in an IL-1ß-dependent or -independent manner. This study offers a detailed characterization of the cellular and molecular alterations induced by chronic HDM exposure and reveals previously unrecognized roles for IL-1ß in orchestrating chronic lung inflammation. Overall design: scRNA-seq profiles of 3-5 months old male C57BL/6 WT or Il1b–/– mice with or without HDM intranasal treatment (3-4 mice/group). The mice were first sensitized intranasallly treated with HDM (50 ug/50 uL) or with the control vehicle (VEH; 50uL, 0.9% sodium chloride solution) on day 0, and were then challenged intranasally three times a week for the subsequent 4 weeks with HDM (12.5 ug/50 uL) or with VEH (50uL). Lungs were harvested and pooled, and the pooled sample was split into two for library preparation and sequencing.