Tanreqing injection inhibits influenza virus replication by promoting the fusion of autophagosomes with lysosomes: An integrated pharmacological study.

ETHNOPHARMACOLOGICAL RELEVANCE: Tanreqing injection (TRQ) is widely used, traditional Chinese medicine (TCM) injection used in China to treat respiratory infections. Modern pharmacological studies have confirmed that TRQ can protect against influenza viruses. However, the mechanism by which TRQ inhibits influenza viruses remains unclear.

AIM OF THE STUDY: To explore the therapeutic effects and possible mechanisms of TRQ inhibition by the influenza virus.

MATERIALS AND METHODS: Ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC/Q-TOF MS) was used to determine the chemical composition of TRQ. Isobaric tags for relative and absolute quantification (iTRAQ) were used to define differential proteins related to TRQ inhibition of viruses. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were performed for functional annotation. For experimental validation, we established an in vitro model of the influenza virus infection by infecting A549 cells with the virus. The detection of the signaling pathway was carried out through qPCR,western blotting,and immunofluorescence.

RESULTS: Fifty one components were identified using UPLC/Q-TOF MS. We confirmed the inhibitory effect of TRQ on influenza virus replication in vitro. Ninety nine differentially expressed proteins related to the inhibitory effect of TRQ were identified using iTRAQ. KEGG functional enrichment analysis showed that the TRQ may inhibit influenza virus replication by affecting autophagy. Through network analysis, 29 targets were selected as major targets, and three key targets, HSPA5, PARP1, and GAPDH, may be the TRQ targets affecting autophagy. In vitro experiments showed that TRQ inhibits influenza virus replication by interfering with the expression and localization of STX17 and VAMP8 proteins, thereby promoting the fusion of autophagosomes with lysosomes.

CONCLUSION: TRQ inhibits influenza virus replication by promoting the fusion of autophagosomes with lysosomes. We additionally established potential gene and protein targets which are affected by TRQ. Therefore, our findings provide new therapeutic targets and a foundation further studies on influenza treatment with TRQ.