Ovarian Hormones and Obesity Drive Th17-mediated Airway Inflammation through Estrogen Receptor Signaling

Abstract

Obesity is a risk factor for increased prevalence and severity of asthma, particularly in females. As adults, females have increased prevalence of asthma compared to males. Yet, the mechanisms remain unclear on how sex hormones and obesity increase airway inflammation. We hypothesize that estrogen signaling through estrogen receptor-alpha (ER-) in T cells increased airway inflammation in the context of obesity. To test our hypothesis, we utilized a high fat (HFD) on female and male mice that underwent ovariectomy or gonadectomy or in Esr1fl/fl X Cd4Cre+ male and female mice. As controls, mice in similar groups were fed normal chow. After 8-12 weeks on diets, house dust mite (HDM) sensitization and challenge occurred in all mice. Lungs and BAL fluid were harvested 24 hours after the last challenge. Ovarian hormones and ER- signaling in T cells increased eosinophils, neutrophils, and Th17-mediated airway inflammation in the lungs of obese female mice. Additionally, using PBMCs from a well-characterized obese asthma cohort, we determined that obese women with asthma had increased Th17 cells compared to obese men with asthma. Our results show that ER- signaling in T cells increases Th17-mediated airway inflammation in obese mice and that Th17 cells circulate at higher frequencies in women with asthma compared to men with asthma. Further research into the interplay between hormonal signaling and immune responses in asthma is essential for developing personalized treatments. One Sentence SummaryEstrogen receptor-alpha signaling, in the context of obesity, increases allergen-induced Th17-mediated airway inflammation in female mice.