Investigation of Glaucocalyxin A Mechanism in Alleviating Atopic Dermatitis via the HMGB1-RAGE-RhoA/ROCK1-Mediated Mitochondrial Pathway

The high mobility group box-1 protein (HMGB1) is crucial in the inflammatory processes associated with atopic dermatitis (AD). The interaction between HMGB1 and its receptor, the receptor for advanced glycation end products (RAGE), plays a central role in mediating inflammation. Nevertheless, the precise mechanisms through which glaucocalyxin A (GLA) influences AD via the HMGB1-RAGE-RhoA/ROCK1 mitochondrial pathway remain to be elucidated. This study aimed to investigate the role of GLA in AD, explore the regulatory effects of the HMGB1-RAGE-RhoA/ROCK1 mitochondrial pathway on inflammatory responses in AD, and identify potential therapeutic targets for the treatment of AD. GLA significantly reduced the levels of inflammatory cytokines (IL-4, TNF-α, IFN-γ) in DNCB-induced AD models. In TNF-α-induced HaCaT cells, treatment with GLA and HMGB1 knockout restored mitochondrial membrane potential and mtROS levels, attenuated mitochondrial fission, and increased the levels of the fusion proteins MFN1 and MFN2. These findings suggest that GLA promotes mitochondrial dynamics by targeting HMGB1. HMGB1 knockout also led to decreased levels of RAGE, RhoA, and ROCK1 proteins. In r-HMGB1-stimulated HaCaT cells treated with a RAGE-specific blocker (TFA), the expression of HMGB1, RAGE, RhoA, and ROCK1 decreased, while levels of MFN1 and MFN2 increased. Similarly, treatment with the Rho kinase inhibitor (Y-27632) reduced p-Drp1 and increased MFN1 and MFN2 levels, though RAGE expression remained unchanged. HMGB1 knockout significantly reduces inflammatory factors in DNCB-induced AD models. HMGB1 promotes mitochondrial fission and inhibits fusion through the HMGB1-RAGE-RhoA/ROCK1 pathway, exacerbating skin inflammation. GLA alleviates AD by modulating the HMGB1-RAGE-RhoA/ROCK1 mitochondrial axis.