Calpeptin may reverse glucocorticoid-resistance of allergic rhinitis associated with cigarette smoke exposure by down-regulating interferon regulatory factor 1.

Cigarette smoke exposure is an important factor in chronic inflammation in patients with allergic rhinitis (AR); however, the relationship between cigarette smoke and AR-related glucocorticoid resistance requires further study. In mice, calpeptin significantly reduces inflammation of the lower respiratory tract caused by cigarette smoke, but whether it can treat glucocorticoid-resistant AR caused by cigarette smoke requires further research. In this study, we confirmed that cigarette smoke exposure can aggravate the Th2 inflammatory response in AR leading to glucocorticoid resistance. The underlying mechanism may be related to decreased expression of DNA methyltransferase 3a (Dnmt3a), and increased expression of interferon regulatory factor 1 (IRF1). In addition, we found that calpeptin can inhibit the expression of IRF1 and thus treat AR-associated glucocorticoid resistance in rats exposed to cigarette smoke. These data suggest that calpeptin may downregulate IRF1 and therefore treat glucocorticoid resistance in AR-associated with cigarette smoke exposure.