Anemoside B4 upregulates DDAH2 and attenuates oxidative stress induced endothelial dysfunction

Endothelial dysfunction, involving diminished nitric oxide (NO) bioavailability and vascular inflammation, plays a pivotal role in cardiovascular disease progression. Anemoside B4 (AB4), a major bioactive component extracted from Pulsatilla chinensis, has been reported to exert anti-inflammatory, anti-tumor, and antiviral effects. However, its potential role in regulating endothelial function remains largely unexplored. Integrating RNA-seq analysis, we revealed that AB4 may exert anti-atherosclerotic effects by upregulating DDAH2 expression and improving endothelial NO production. Using an H₂O₂-induced endothelial cell dysfunction model, we found that AB4 significantly reversed H₂O₂-induced impairments in endothelial cell viability and migration, while attenuating apoptosis and reducing monocyte adhesion. In addition, AB4 upregulated DDAH2 protein expression, restored eNOS phosphorylation, and increased NO production under oxidative stress conditions. Pharmacological perturbation of DDAH2 protein expression with PD404182 attenuated the AB4-mediated restoration of eNOS-NO signaling and weakened its inhibitory effects on monocyte-endothelial adhesion and ICAM-1/VCAM-1 expression. Consistently, in a mouse model of oxidative stress-induced endothelial dysfunction, AB4 increased endothelial DDAH2 protein expression, enhanced NO production, and suppressed endothelial ICAM-1 and VCAM-1 expression. These effects were attenuated by PD404182, supporting the involvement of DDAH2 regulation in the endothelial protective effects of AB4. Taken together, these results suggest that AB4 restores endothelial eNOS-NO signaling and counteracts oxidative stress-induced endothelial dysfunction, evidenced by enhanced viability, improved migration, and reduced apoptosis and inflammation, with these effects being associated with DDAH2 upregulation.