Glycosides of Buyang Huanwu decoction alleviate cerebral infarction injury by inhibiting neuronal pyroptosis via astrocyte-derived exosomal miR-378b_L+1.

ETHNOPHARMACOLOGICAL RELEVANCE: Buyang Huanwu Decoction (BYHWD) is a classic and renowned formula for the treatment of cerebral infarction (CI). The effective glycosides are the key pharmacodynamic substances of BYHWD in treating cerebral infarction, and its neuroprotective effect is closely related to the regulation of the classical pyroptosis pathway. Our recent study revealed that Astrocyte Exosomes (Ast-Exo) play an important role in signal transmission and regulation in the pathological process of pyroptosis after cerebral infarction through the miRNAs they carry. However, whether the glycosides can exert an anti-pyroptosis effect by regulating astrocyte exosomes needs further exploration.

AIM OF THE STUDY: This study aims to explore the effect of the glycosides of BYHWD in inhibiting neuronal pyroptosis after cerebral infarction by regulating astrocyte exosomes and their microRNAs (miRNAs).

MATERIALS AND METHODS: Ultra-Performance Liquid Chromatography-Time-of-Flight Mass Spectrometry (UPLC-Q-TOF MS) was used to identify the glycosides in the serum. A rat model of middle cerebral artery occlusion (MCAO) and an oxygen glucose deprivation (OGD) model were established. By detecting neurons injury and the expression of pyroptosis-related proteins, the relationship between the regulation of neuronal pyroptosis after cerebral infarction by the glycosides of BYHWD and astrocyte exosomes was clarified. Furthermore, methods such as miRNA microarray detection, bioinformatics prediction, and qPCR were used to screen an astrocyte exosome miRNA (abbreviated as: candidate miRNA) that is most closely related to the regulation of pyroptosis by the glycosides of BYHWD. Finally, an in vitro model of neuronal OGD injury was established, and astrocyte exosomes carrying high and low expressions of the candidate miRNA were constructed. By detecting neurons injury and the expression of pyroptosis-related proteins, the relationship between the anti-OGD injury effect of the glycosides of BYHWD on neuronal pyroptosis and the regulation of the candidate miRNA was clarified, and the molecular mechanism by which the glycosides of BYHWD regulate neuronal pyroptosis after cerebral infarction was revealed through the candidate miRNA pathway of exosomes.

RESULTS: Studies on whole animals and in vitro cells have shown that the glycosides and astrocyte exosomes have a synergistic effect in repairing neuronal damage after cerebral infarction and inhibiting pyroptosis. The results of high-throughput sequencing and qRT-PCR have found that astrocyte exosome miR-378b_L+1 is the key miRNA for the glycosides to inhibit pyroptosis. After the synergistic intervention of the glycosides and astrocyte exosomes carrying a high expression of miR-378b_L+1, the expressions of the pyroptosis-related proteins Gasdermin D (GSDMD), NOD-like receptor pyrin domain-containing protein 3 (NLRP3), and Cysteinyl aspartate-specific proteinase-1 p20 (Caspase-1 p20) decreased. However, knocking down miR-378b_L+1 exacerbated pyroptosis, thus reversing the neuroprotective effect of the glycosides.

CONCLUSION: The glycosides (mainly including Astragaloside IV, Paeoniflorin and Amygdalin) inhibit neuronal pyroptosis by regulating astrocyte exosome miR-378b_L+1, and exert a neuroprotective effect on cerebral infarction.