IL-33 down-regulates CLDN1 expression through the ERK/STAT3 pathway in keratinocytes

A skin barrier defect is a well-known distinctive feature of atopic dermatitis (AD). Stratum corneum (SC) and tight junction (TJ) molecules play important roles in the barrier function of keratinocytes [1]. TJs are major barrier structures of the skin, tightly connecting neighboring cells and restricting the paracellular passage of substances [2]. TJs are composed of numerous proteins such as occludin (OCLN), junctional adhesion molecule A, zonula occludens (ZO)-1 and, −2, cingulin, symplekin, and claudin (CLDN) [2].