Astragaloside IV alleviates LPS-induced acute lung injury by regulating receptor C5aR1 and macrophage pyroptosis

Astragaloside IV (AS-IV), derived from Astragalus membranaceus, exhibits significant anti-inflammatory properties in a variety of diseases. However, the specific anti-inflammatory mechanism of AS-IV depends on the different organs and doses. Its protective effect is still unknown in acute lung injury (ALI). This study aims to investigate the potential anti-inflammatory mechanism of AS-IV in ALI. Lipopolysaccharide (LPS) and adenosine triphosphate (ATP) were utilized to form Pyroptosis models in MH-S and RAW264.7 cells. Mouse model of ALI was induced by intranasal LPS administration. In addition, the anti-pyroptosis effect of AS-IV was evaluated by using the C5aR1 agonists BM-213, the C5aR1 overexpression plasmids and C5aR1 siRNA. AS-IV significantly reduced pulmonary edema, improved histopathological injury, and decreased inflammatory factors. Meanwhile, AS-IV reduced ROS level and the amount of NLRP3 and GSDMD-N in vitro and in vivo. Inhibiting C5aR1 can effectively and significantly alleviate the Pyroptosis of alveolar macrophages. Further studies found that BM-213 and C5aR1 overexpression plasmids partially reversed the anti-pyroptosis effect of AS-IV. The anti-pyroptosis effect of AS-IV was significantly inhibited when C5aR1 was knocked down. Our study demonstrate that AS-IV has anti-inflammatory protective effects on LPS-induced ALI, indicating that AS-IV may be a potential therapeutic agent for the treatment of ALI. This effect may be achieved by reducing the content of C5a, lowering the expression of C5aR1, and inhibiting cell Pyroptosis.

Acute lung injury; Astragaloside IV; C5a; C5aR1; Macrophage; Pyroptosis.