Caspase-14 Activation by Chaenomeles sinensis May Enhance Skin Barrier Function

Atopic dermatitis (AD) is characterized by chronic itching and significant loss of skin barrier function. Decreased filaggrin levels have been observed in several patients with AD and are thought to be responsible for impaired barrier function. Caspase-14 is an important factor in maintaining skin barrier function and is involved in the production of natural moisturizing factors by degrading filaggrin. We have been conducting research on Chaenomeles sinensis extract (CSE) and confirmed its anti-aging effects. In this study, we investigated the effects of CSE on caspase-14 expression. CSE-induced changes in gene expression were confirmed in human keratinocytes using DNA microarray and quantitative polymerase chain reaction (qPCR), and the expression of caspase-14 increased. This was confirmed at the protein level using western blotting. Furthermore, CSE increased the expression of kallikrein (KLK) 5 and KLK7, which are involved in skin barrier function, as well as caspase-14. In the investigation of the activation of these factors, CSE promoted activation of caspase-14, KLK5, and KLK7. Moreover, procyanidin B2, gallocatechin gallate, and quercetin were identified using HPLC as CSE components, confirming the strong promotion of caspase-14 activity by quercetin. These results suggest that CSE effectively improves skin barrier function by promoting the expression and activation of caspase-14.