Saponins from Allium macrostemon Bulbs Attenuate Endothelial Inflammation and Acute Lung Injury via the NF-κB/VCAM-1 Pathway

Abstract

Endothelial inflammation is a multifaceted physiological process that plays a pivotal role in the pathogenesis and progression of diverse diseases, encompassing but not limited to acute lung infections like COVID-19, coronary artery disease, stroke, sepsis, metabolic syndrome, certain malignancies, and even psychiatric disorders such as depression. This inflammatory response is characterized by augmented expression of adhesion molecules and secretion of pro-inflammatory cytokines. In this study, we discovered that saponins from Allium macrostemon bulbs (SAMB) effectively inhibited inflammation in human umbilical vein endothelial cells induced by the exogenous inflammatory mediator lipopolysaccharide or the endogenous inflammatory mediator tumor necrosis factor-α, as evidenced by a significant reduction in the expression of pro-inflammatory factors and vascular cell adhesion molecule-1 (VCAM-1) with decreased monocyte adhesion. By employing the NF-κB inhibitor BAY-117082, we demonstrated that the inhibitory effect of SAMB on VCAM-1 expression may be attributed to the NF-κB pathway’s inactivation, as characterized by the suppressed IκBα degradation and NF-κB p65 phosphorylation. Subsequently, we employed a murine model of lipopolysaccharide-induced septic acute lung injury to substantiate the potential of SAMB in ameliorating endothelial inflammation and acute lung injury in vivo. These findings provide novel insight into potential preventive and therapeutic strategies for the clinical management of diseases associated with endothelial inflammation.