Schizandrin B attenuates angiotensin II induced endothelial to mesenchymal transition in vascular endothelium by suppressing NF-κB activation

Background: Angiotensin II (Ang II)-induced chronic inflammation and oxidative stress often leads to irreversible vascular injury, in which the endothelial to mesenchymal transition (EndMT) in the endothelial layers are involved. Schisandrin B (Sch B), a natural product isolated from traditional Schisandra chinensis, has been reported to exert vascular protective properties with unclear mechanism. Hypothesis/purpose: This study investigated the protective effects and mechanism of Sch B against Ang II-induced vascular injury. Methods: C57BL/6 mice were subcutaneous injected of Ang II for 4 weeks to induce irreversible vascular injury. In vitro, Ang II-induced HUVECs injury was used to study the underlying mechanism. The markers of EndMT, inflammation and oxidative stress were studied both in vitro and in vivo. Results: Pre-administration of Sch B effectively attenuated phenotypes of vascular EndMT and fibrosis in Ang II-treated animals, accompanied with decreased inflammatory cytokine and ROS. The in vitro data from HUVECs suggest that Sch B directly targets NF-kappa B activation to suppress Ang II-induced EndMT and vascular injury. The activation of EndMT in the presence of Ang II is regulated by the NF-kappa B, a common player in inflammation and oxidative stress. Ang II-induced inflammation and oxidative stress also contributed to vascular EndMT development and Sch B inhibited inflammation/ROS-mediated EndMT by suppressing NF-kappa B. Conclusion: EndMT contributes to vascular injury in Ang II-treated mice, and it can be prevented via suppressing NF-kappa B activation by Sch B treatment. These results also imply that NF-kappa B might be a promising target to attenuate vascular remodeling induced by inflammation and oxidative stress through an EndMT mechanism.