Eburicoic acid inhibits endothelial cell pyroptosis and retards the development of atherosclerosis through the Keap1/Nrf2/HO‑1/ROS pathway.

Abstract

Atherosclerosis (AS)‑related coronary artery disease is the main cause of morbidity and mortality around the globe. Eburicoic acid, a triterpenoid compound from Antrodia camphorata, exerts anti‑inflammatory and anti‑hyperlipidemic effects, although its role in atherogenesis remains unknown. Endothelial cell pyroptosis‑caused chronic inflammatory response within vessel walls is a critical initial event in atherogenesis, making it a promising target to prevent AS. The present study was designed to investigate the effects of eburicoic acid on endothelial cell pyroptosis, AS progression and the underlying mechanisms. The results showed that with dose and time increased, treatment of human umbilical vascular endothelial cells (HUVECs) with eburicoic acid markedly decreased the expression of Kelch‑like ECH‑associated protein 1 (Keap1), NF‑E2‑related factor 2 (Nrf2), reactive oxygen species (ROS), NLR family pyrin domain‑containing protein 3 (NLRP3), cleaved caspase‑1, apoptosis‑associated speck‑like protein containing CARD (ASC), N‑terminal gasdermin‑D (GSDMD‑N), downregulated the secretion levels of pro‑inflammatory cytokines interleukin (IL) 1β, IL‑6 and IL‑18, inhibited caspase‑1 activity and lactate dehydrogenase release and improved plasma membrane integrity. By contrast, the expression of nuclear Nrf2, total Nrf2 and heme oxygenase‑1 (HO‑1) were increased by eburicoic acid treatment in HUVECs dose‑ and time‑dependently. Moreover, the inhibitory effects of eburicoic acid on HUVEC pyroptosis were mainly compromised by pre‑treatment with ROS agonist, HO‑1 small interfering (si)RNA, or Nrf2 siRNA. Finally, it was observed that administering high‑fat‑diet fed ApoE‑/‑ mice with eburicoic acid markedly increased Nrf2 and HO‑1 levels and reduced the expression of Keap1, NLRP3, cleaved caspase‑1, ASC and GSDMD‑N in aortas and ameliorated hyperlipidemia and inflammation in the serum, leading to smaller atherosclerotic plaques, less lipid accumulation and high content of collagen fiber within plaques. These findings identified eburicoic acid as a potent anti‑atherogenic natural product by suppressing endothelial cell pyroptosis via the Keap1/Nrf2/HO‑1/ROS pathway. Eburicoic acid may be considered an effective phytomedicine for treating AS.