Baicalein inhibits the Th1 / Th17-mediated inflammatory response by targeting STAT1/3 in EAE mice

Abstract

Abstract Helper T cells (Th) play a crucial role in the pathogenesis of multiple sclerosis (MS) and experimental encephalomyelitis (EAE). Th1/17 cells contribute to neuroinflammation through inflammatory infiltration and cytokine secretion, however, effective therapeutic interventions are currently lacking. Baicalein (BAI), the principal component of Scutellaria baicalensis, is a dietary supplement that has demonstrated efficacy in the fields of anti-inflammatory, neuroprotection, and immunomodulation. The activation the JAK-STAT signalling pathway in Th1/17 cells may play a pivotal role in the initiation and progression of inflammation associated with MS/EAE. Therefore, this study aimed to investigate whether BAI could mitigate the inflammatory response of Th1/17 cells by modulating JAK-STAT signaling. Flow cytometry, quantitative real-time PCR and western blotting were used to detect the ratio of Th1 and Th17 cells, the expression of related cytokines in EAE model mice treated with BAI, as well as the expression of proteins related to the JAK/STAT signaling pathway. The findings demonstrated that BAI exhibited therapeutic efficacy in EAE mice by significantly reducing the proportion of Th1 and Th17 cell populations along with the expression levels of relevant inflammatory cytokines. Moreover, transcription factors T-bet and ROR-γt showed significant downregulation in response to BAI treatment. This effect may be attributed to BAI's ability to inhibit STAT1/3 phosphorylation. Subsequently, molecular docking, pull-down and immunofluorescence experiments confirmed that BAI bound to STAT1/3, and caused p-STAT1/3 to remain in the cytoplasm, hindering JAK/STAT signal transduction and thus inhibiting the inflammatory response of the Th1/17 cells.