Potential Natural Biomolecules Targeting JAK/STAT/SOCS Signaling in the Management of Atopic Dermatitis

Atopic dermatitis (AD) is a chronic inflammatory skin disease caused by the dysregulation of cytokines and other immune mediators. JAK/STAT is a classical signal transduction pathway involved in various biological processes, and its dysregulation contributes to the key aspects of AD pathogenesis. Suppressor of cytokine signaling (SOCS) proteins negatively regulate the immune-related inflammatory responses mediated by the JAK/STAT pathway. JAK/STAT-mediated production of cytokines including IL-4, IL-13, IL-31, and TSLP inhibits the expression of important skin barrier proteins and triggers pruritus in AD. The expression of SOCS proteins regulates the JAK-mediated cytokines and facilitates maintaining the skin barrier disruptions seen in AD. STATs are crucial in dendritic-cell-activated Th2 cell differentiation in the skin, releasing inflammatory cytokines, indicating that AD is a Th2-mediated skin disorder. SOCS proteins aid in balancing Th1/Th2 cells and, moreover, regulate the onset and maintenance of Th2-mediated allergic responses by reducing the Th2 cell activation and differentiation. SOCS proteins play a pivotal role in inflammatory cytokine-signaling events that act via the JAK/STAT pathway. Therapies relying on natural products and derived biomolecules have proven beneficial in AD when compared with the synthetic regimen. In this review, we focused on the available literature on the potential natural-product-derived biomolecules targeting JAK/STAT/SOCS signaling, mainly emphasizing the SOCS family of proteins (SOCS1, SOCS3, and SOCS5) acting as negative regulators in modulating JAK/STAT-mediated responses in AD pathogenesis and other inflammatory disorders.

Leonurine ameliorates D-galactose-induced aging in mice through activation of the Nrf2 signalling pathway

Aging is a complex physiological phenomenon associated with oxidative stress damage. The objective of this study was to investigate the potential effects of leonurine on D-galactose-induced aging in mice and its possible mechanisms. In this study, we first tested the antioxidant activity of leonurine in vitro. A subcutaneous injection of D-galactose in mice for 8 weeks was used to establish the aging model to evaluate the protective effects of leonurine. The results showed that treatment with 150 mg·kg^-1 leonurine could improve the mental condition, organic index, and behavioural impairment; significantly increase the activities of antioxidative enzymes including SOD, CAT, and T-AOC; and ameliorate the advanced glycation end product (AGE) level and histopathological injury. Furthermore, the Western blotting data revealed that leonurine supplementation noticeably modulated the suppression of the Nrf2 pathway and upregulated the downstream expression of HO-1 and NOQ1 in aging mice. Additionally, leonurine treatment activated Nrf2 nuclear translocation in both aging mice and normal young mice, and the expression levels of Nrf2 in normal young mice was higher than those in naturally aging mice. In conclusion, our findings suggest that leonurine is a promising agent for attenuating the aging process, and the underlying molecular mechanisms depend on activating the Nrf2 pathway.