C34-03 Dysregulation of Airway Epithelium by the Transcription Factor Sox9 in Asthma

Abstract Rationale Asthma is a chronic inflammatory lung disease, affecting 26 million people in the United States alone and causing over 300 million USD in healthcare costs annually. Heightened inflammation, mucus production, subepithelial airway thickening, and airway hyperresponsiveness (AHR) are major characteristics of asthma. Although dysregulated airway epithelium has been implicated in inflammation, airway remodeling, and AHR in asthma, the transcriptional regulators of airway epithelial cells involved in asthma pathogenesis remain poorly understood. Here, we hypothesized that Sox9 upregulation in airway epithelial cells worsens airway inflammation and AHR during allergen-induced asthma. Methods To determine Sox9 upregulation in airways and cell types involved, we performed immunohistochemistry and immunofluorescence staining on lung sections from human asthma patients and a mouse model of house dust mite (HDM)-induced allergic asthma. To assess the effects of Sox9 on airway epithelial cells, we overexpressed Sox9 using lentiviral vectors in BCi NS1.1 cells cultured in air-liquid interface (ALI) and measured asthma-associated gene expression using RT-PCR. To assess in vivo effects of Sox9, we generated doxycycline-inducible CCSP-rtTA:TetO-Sox9 (cSox9OE) mice and administered intranasal treatments with either saline or HDM protein (25 µg) five times per week for three weeks. After the final challenge, lung function parameters were assessed, bronchoalveolar lavage (BAL) cells quantified, and lungs were collected for histological and biochemical analyses. Results In ALI-cultures, Sox9 overexpression induced upregulation of asthma-associated genes, including MUC5AC, and the chemokines CCL2 and CCL5. In vivo, Sox9 overexpression in airway club cells increases HDM-induced AHR and inflammatory responses in asthma. Lungs from cSox9OE mice exhibited elevated levels of IFNγ, IL-6, IL-4, CCL11, and ARG1 compared to HDM-treated control mice. Consistently, BAL fluid from cSox9OE mice showed increased total immune cell and eosinophil counts with HDM-treatment. Conclusions Increased Sox9 expression in club cells promotes pathological airway inflammation and AHR during asthma. Future studies will elucidate the mechanisms through which Sox9 is involved in airway inflammation and AHR during asthma. This study is supported by NIH (1R01 HL134801 &1R01 HL157176) This abstract is funded by: NIH 1R01 HL134801 &1R01 HL157176