Yi-Qi-Ping-Chuan-Fang Reduces TSLP Elevation Caused by LPS + Poly(I:C) via Inhibiting TLR4/MYD88/NF-κB Signaling Pathway

OBJECTIVE: To explore the correlation between Thymic Stromal Lymphopoietin (TSLP) and the Nuclear Factor- (NF-) κB signaling pathways in bronchial epithelial cells and to clarify whether the traditional Chinese medicine formula Yi-Qi-Ping-Chuan-Fang (YQPC) reduces inflammation by inhibiting TSLP/NF-κB signaling pathways. METHODS: Cells were stimulated with LPS + Poly(I:C) and treated with YQPC. The expressions of TSLP and NF-κB signaling pathways related proteins P65, IκK, IκBa, P-P65, P-IκK, P-IκBa were detected. The effects of NF-κB upstream molecules, Toll-like receptors 3 and 4, myeloid differentiation primary response gene 88 (Myd88), TIR-domain-containing adapter-inducing interferon-β (TRIF), and downstream inflammatory cytokines, TNF-α, IL-1β, IL-6, and IL-8, were assessed. RESULTS: The mRNA and protein expressions of TSLP were significantly increased after LPS + Poly(I:C) stimulation, the total protein IκBa and IκK decreased (P < 0.05), and the phosphorylated protein P-P65, P-IκK, and P-IκBα increased. After YQPC treatment, the expression of TSLP, P-P65, P-IκBa, and P-IκK was significantly inhibited (P < 0.05). The activation of TLR4 and MyD88 decreased, and release of IL-1β, IL-6, IL-8, and TNF-α reduced (P < 0.05). CONCLUSION: In summary, the expression of TSLP is activated by the NF-κB signaling pathway. YQPC alleviated inflammation by inhibiting TSLP through regulating the NF-κB activation and translocation.