Kaempferol-7-O-Glucoside Ameliorates Atopic Dermatitis via the TSLP-Mediated JAK2/STAT5 Signaling Axis.

Background/

Objectives

Thymic stromal lymphopoietin (TSLP) is central to the pathogenesis of atopic dermatitis (AD) and a promising therapeutic target. However, developing small-molecule TSLP inhibitors is challenging due to the difficulty in disrupting the TSLP-TSLPR interface. This study aimed to explore naturally sourced blockers of the TSLP-TSLPR interaction and identify novel candidate compounds for AD treatment.

Methods

HuT78 cells were stimulated with PMA, ionomycin, and TSLP to establish an AD model. Inflammatory cytokines were measured by qRT-PCR and ELISA. JAK/STAT signaling was analyzed by Western blot. In female BALB/c mice, DNCB-induced AD-like skin lesions were topically treated with test compounds, followed by histopathological and immunohistochemical assessment.

Results

Eight compounds were screened, and their key structural features were elucidated via structure-activity relationship (SAR) analysis. Among them, kaempferol-7-O-glucoside (K-7-G) emerged as the most potent candidate. It interfered with the TSLP-TSLPR interaction, selectively inhibited TSLP-mediated JAK2/STAT5 phosphorylation, and significantly downregulated IL-4 (p < 0.0001) and IL-13 (p < 0.001) levels. Topical application of 1% K-7-G significantly alleviated AD-like symptoms in a mouse model, decreasing dorsal skin thickness, dermatitis score, and scratching frequency while restoring the expression of filaggrin, loricrin, and occludin (p < 0.0001). Meanwhile, it significantly reduced key inflammatory mediators in a concentration-dependent manner, including TSLP, IL-4, IL-13, TNF-α, IFN-γ, and IgE.

Conclusions

This study demonstrates that K-7-G is a novel natural TSLP inhibitor capable of blocking the TSLP-TSLPR signaling pathway and effectively improving AD symptoms. Further research may explore its therapeutic potential in other inflammatory diseases.