The BCL2/BAX/ROS pathway is involved in the inhibitory effect of astragaloside IV on pyroptosis in human umbilical vein endothelial cells

Abstract

Context Astragaloside IV (AS-IV) is extracted from Astragalus membranaceus (Fisch.) Bunge (Fabaceae). However, its effects on endothelial cell injury remain unclear.Objective To investigate the mechanisms underlying the effects of AS-IV on lipopolysaccharide (LPS)-induced endothelial injury in vitro.Materials and methods Human umbilical vein endothelial cells (HUVECs) were pre-treated with AS-IV (100 µmol/mL), 4-hydroxy-3-methoxyacetophenone (APO, 10 µmol/mL), N-acetylcysteine (NAC, 50 µmol/mL) and Ac-YVAD-cmk (AC, 5 µmol/mL) for 2 h before 1 μg/mL LPS 24 h exposure. Untreated cells cultured without any exposure were used as controls. Cell viability, reactive oxygen species (ROS) and pyroptosis assays were performed. The pyroptosis related proteins were detected by western blot.Results The rate in late pyroptosis (Q2-2) of AS-IV (13.65 ± 0.74%), APO (13.69 ± 0.67%) and NAC (15.87 ± 0.46%) groups was lower than the LPS group (21.89 ± 0.66%, p < 0.05), while the rate in early pyroptosis (Q2-4) of AS-IV group (12.00 ± 0.26%) was lower than other groups (p < 0.05). The expression of NOX4, GSDMD, NLRP3, ASC and caspase-1 decreased after AS-IV, NAC or AC intervention (p < 0.05). The ROS production in AS-IV (4664 ± 153.20), APO (4094 ± 78.37), NAC (5103 ± 131.10) and AC (3994 ± 102.50) groups was lower than the LPS (5986 ± 127.30) group, while the mitochondrial BCL2/BAX protein expression ratio increased in AS-IV, APO and NAC groups (p < 0.05).Discussion and conclusions AS-IV suppressed pyroptosis in LPS-activated HUVECs by inducing ROS/NLRP3-mediated inhibition of the inflammatory response, providing a scientific basis for clinical applications of AS-IV.

Keywords

• Sepsis
• lipopolysaccharide
• mitochondria
• inflammasome
• endothelial injury