Epicutaneous Staphylococcus aureusexposure triggers lung inflammation via epithelia-intrinsic IL-36R signaling

Abstract

Abstract Allergic diseases have been increasing recently and affect nearly 20% of the human population, including 200 million people with atopic dermatitis (AD), 250 million people with food allergies, and 600 million people with allergic rhinitis or asthma. The atopic march is the concept whereby having early-in-life AD and a dysfunctional skin barrier during initial allergen sensitization increases the predisposition of allergic diseases at distant epithelial sites (e.g., asthma). We have previously shown that IL-36R signaling was required to exacerbate the progression from AD-like skin inflammation to subsequent allergic lung inflammation in mice. However, whether IL-36R acts directly on the skin and/or lung epithelia to trigger the progression towards lung inflammation is not entirely clear. To address this gap in knowledge, we performed our allergic lung inflammation model in WT, IL-36R−/−, keratinocyte-specific IL-36R deficient (K14-cre×IL-36R fl/fl), and lung epithelial-specific IL-36R deficient (Nkx2-1-cre×IL-36R fl/fl) mice, whereby first epicutaneous Staphylococcus aureus and cockroach antigen (CrA) exposure initiates AD-like skin inflammation, which is followed by intratracheal CrA exposure to trigger subsequent allergic lung inflammation. Evaluation of skin and lung inflammation by image, histologic and flow cytometric analyses revealed that both keratinocyte- and lung epithelial-intrinsic IL-36R signaling were required for the development of lung inflammation, weight loss, and neutrophil lung infiltration despite no differences in circulating neutrophils. Collectively, our findings suggest that IL-36R signaling in skin and lung epithelia is a critical mechanism for the progression of the atopic march. NIAMS: R01AR073665 and LEO Foundation: LF-OC-22-000953; SJN is funded by NIAMS 1T32AR074920