LXA4 inhibits TGF-β1-induced airway smooth muscle cells proliferation and migration by suppressing the Smad/YAP pathway.

• TGF-β1 up-regulated YAP expression by activating Smad2/3, and then up-regulated cyclin D1 leading to rat ASMCs proliferation and migration. • Knockdown of YAP disrupted the pro-airway remodeling function of TGF-β1. • LXA4 inhibited TGF-β1 induced ASMCs proliferation and migration. • LXA4 blocked TGF-β1-induced activation of Smad2/3, YAP and cyclin D1 via its receptor FPRL1. The aims of the present study were to examine the signaling mechanisms for transforming growth factor-β1 (TGF-β1)-induced rat airway smooth muscle cells (ASMCs) proliferation and migration and to determine the effect of lipoxin A4 (LXA4) on TGF-β1-induced rat ASMCs proliferation and migration and its underlying mechanisms. TGF-β1 upregulated transcriptional coactivator Yes-associated protein (YAP) expression by activating Smad2/3 and then upregulated cyclin D1, leading to rat ASMCs proliferation and migration. This effect was reversed after treatment with the TGF-β1 receptor inhibitor SB431542. YAP is a critical mediator of TGF-β1-induced ASMCs proliferation and migration. Knockdown of YAP disrupted the pro-airway remodeling function of TGF-β1. Preincubation of rat ASMCs with LXA4 blocked TGF-β1-induced activation of Smad2/3 and changed its downstream targets, YAP and cyclin D1, resulting in the inhibition of rat ASMCs proliferation and migration. Our study suggests that LXA4 suppresses Smad/YAP signaling to inhibit rat ASMCs proliferation and migration and therefore has potential value in the prevention and treatment of asthma by negatively modulating airway remodeling. [ABSTRACT FROM AUTHOR]