Inhibition of semaphorin-3a alleviates lipopolysaccharide-induced vascular injury

Alleviating vascular injury improves the prognosis of atherosclerosis. Semaphorin-3a (Sema3A) is a special membrane-associated secreted protein with various biological properties, like pro-inflammation, anti-tumor and et al. This study aims to investigate the effects of inhibition of Sema3A on lipopolysaccharide (LPS)-induced vascular injury in mice. The mice were randomized into three groups: control, LPS, and LPS + siRNA. Mice in the combined group were given siRNA through fast tail vein injection, then LPS was injected intraperitoneally 7 days later, finally the mice were euthanized 24 h later. Vascular function and structure were assessed by vascular injury biomarkers and relevant stainings. LPS-induced vascular dysfunction and pathological injury were substantially improved by inhibition of Sema3A. Western blot and quantitative real-time polymerase chain reaction assays were used for investigating molecular pathways. The relevant proteins of vascular endothelial cells activation, intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1), increased after LPS stimulation, while these effects were reversed by inhibition of Sema3A. The levels of inflammatory cytokines (IL-1β, IL-6 and NLRP3) were upregulated after LPS stimulation, however, inhibition of Sema3A reversed it through NF-κB and MAPKs signaling pathways involvement. Moreover, inhibition of Sema3A alleviated LPS-induced oxidative stress, evidenced by a decrease in total reactive oxygen species and an increase in antioxidant protein of SOD-1. The results showed that inhibition of Sema3A protects against LPS-induced vascular injury by suppressing vascular endothelial cells activation, vascular inflammation, and vascular oxidative stress, implying that inhibition of Sema3A might be used as a therapeutic strategy for septic vascular injury or atherosclerosis.