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

Objective: To explore the correlation between Thymic Stromal Lymphopoietin (TSLP) and the Nuclear Factor- (NF-) κ B 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- κ B signaling pathways.

Methods: Cells were stimulated with LPS + Poly(I:C) and treated with YQPC. The expressions of TSLP and NF- κ B signaling pathways related proteins P65, I κ K, I κ Ba, P-P65, P-I κ K, P-I κ Ba were detected. The effects of NF- κ B 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-1 β , 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 I κ Ba and I κ K decreased ( P < 0.05), and the phosphorylated protein P-P65, P-I κ K, and P-I κ B α increased. After YQPC treatment, the expression of TSLP, P-P65, P-I κ Ba, and P-I κ K was significantly inhibited ( P < 0.05). The activation of TLR4 and MyD88 decreased, and release of IL-1 β , IL-6, IL-8, and TNF- α reduced ( P < 0.05).

Conclusion: In summary, the expression of TSLP is activated by the NF- κ B signaling pathway. YQPC alleviated inflammation by inhibiting TSLP through regulating the NF- κ B activation and translocation.