AS-IV's protective potential against inflammatory injury via miR-320b/PTEN axis in acute ischaemic stroke

Astragaloside IV (AS-IV) represented a promising therapeutic candidate for acute ischaemic stroke. However, its definitive molecular targets and mode of action await full elucidation.The study investigated the protective efficacy of AS-IV and delineated its underlying mechanism in regulating human brain microvascular endothelial cells (BMECs) following oxygen-glucose deprivation/reoxygenation (OGD/R) conditions.Human BMECs were exposed to OGD conditions for 4 h and AS-IV (0-100 µM) was added to the medium immediately for reoxygenating treatment. MiR-320b levels were manipulated 24 h after OGD/R by transient transfection with its inhibitor or mimic. Cell viability and apoptosis were assessed by corresponding kits. The expression level of miR-320b or PTEN was achieved by RT-qPCR. Pro-inflammatory cytokines were detected by ELISA.AS-IV rescued cells under OGD/R condition by enhancing cell viability, curbing apoptosis and pro-inflammatory signalling. This aligned with the pro-survival signature of miR-320b upregulation in OGD/R cells. Conversely, miR-320b knockdown abrogated the AS-IV efficacy. RIP and dual-luciferase reporter assay confirmed PTEN as the direct downstream target of miR-320b.AS-IV protected cells under OGD/R conditions by improving viability and inhibiting inflammation as well as apoptosis via miR-320b/PTEN axis.