Attenuated airway hyperresponsiveness and mucus secretion in HDM exposed Igf1r-deficient mice

Asthma is a common disease characterized by airflow obstruction, airway hyperresponsiveness (AHR) and inflammation affecting people from childhood to old age. IGFs have been reported to play a role in asthma but little is known about how the Insulin-like Growth Factor 1 Receptor (IGF1R) affects asthma pathobiology. In oder to determine the role of Igf1r in the asmatic response, female Igf1r-deficient (López el al. Transgenic Res 2015; 24:279-94) and control mice were intranasally challenged with house dust mite (HDM) extract or PBS five days per week for four weeks. Lung function measurements, and bronchioalveolar lavage fluid (BALF), serum and lungs were collected on day 28 for further cellular, histological and molecular analysis. Following HDM exposure, the control mice responded with a marked AHR and airway inflammation. The Igf1r-deficient mice exhibited an increased expression of the IGF system and surfactant genes, which were decreased in a similar manner for control and Igf1r-deficient mice after HDM exposure. On the other hand, the Igf1r-deficient mice exhibited no AHR, and a selective decrease of blood and BALF eosinophils, lung Il13 levels, collagen and smooth muscle, as well as a significant depletion of goblet cell metaplasia and mucus secretion markers after HDM exposure. The Igf1r-deficient mice displayed a distinctly thinner epithelial layer than control mice, but this was not altered by HDM. Our data demonstrate by the first time that the Igf1r plays an important role in murine asthma, mediating both AHR and mucus secretion after HDM exposure. Thus, our study identifies IGF1R as a potential therapeutic target, not only for asthma but also for hypersecretory airway diseases.