Inhibitory functions of Veratramine on high mobility group box protein 1-mediated severe inflammatory responses

Abstract The protein high mobility group box 1 (HMGB1) acts as a pivotal factor in late-phase sepsis by promoting the secretion of proinflammatory cytokines. Increased concentrations of HMGB1 in the blood are associated with diagnostic challenges, poor prognostic outcomes, and aggravated disease severity in inflammatory states. Veratramine (VRT), a natural steroidal alkaloid present in the Veratrum genus of the lily family, has demonstrated several pharmacological activities, including tumor suppression, blood pressure reduction, cosmetic benefits, and pain relief, but its influence on HMGB1-mediated vascular inflammation has not been well elucidated. The present investigation set out to determine whether VRT might influence lipopolysaccharide (LPS)-induced HMGB1 functions and associated inflammatory cascades in human endothelial cells. HMGB1 release was measured by competitive ELISA. Endothelial permeability was evaluated through Evans blue-albumin translocation assays in vitro and vascular leakage assays in vivo. Reactive oxygen species (ROS) production, antioxidant enzyme activities (SOD, CAT, GSH-Px), and lipid peroxidation (MDA) levels were analyzed using spectrophotometric assays and ELISAs. Expression levels of cell adhesion molecules (ICAM-1, VCAM-1, E-selectin), NF-κB, TNF-α, and pattern recognition receptors (TLR2, TLR4, RAGE) were quantified. VRT significantly inhibited LPS-induced HMGB1 secretion and reduced HMGB1-triggered endothelial hyperpermeability. VRT suppressed intracellular ROS generation, restored antioxidant enzyme activities, lowered MDA levels, and attenuated HMGB1-induced NF-κB activation and TNF-α production. Furthermore, VRT selectively downregulated RAGE expression without disrupting HMGB1-RAGE binding. In vivo, VRT reduced HMGB1-induced vascular leakage. Collectively, these results indicate that VRT can effectively dampen HMGB1-driven inflammatory responses and may serve as a potential intervention for inflammation-related conditions.