3,4,5-Tri-O-caffeoylquinic acid methyl ester isolated from Lonicera japonica Thunb. Flower buds facilitates hepatitis B virus replication in HepG2.2.15 cells

Abstract

Caffeoylquinic acids are well known for their prominent antiviral activities. Beyond our expectations, we initially found 3,4,5-Tri-O-caffeoylquinic acid methyl ester (3,4,5-CQME) from L. japonica can facilitate HBV DNA and antigens secretion. This study aimed to investigate its underlying molecular mechanism. The results indicate that 3,4,5-CQME signally increased intracellular and secreted HBsAg levels by more than two times in HepG2.2.15 cells and HepAD38 cells. Furthermore, levels of HBeAg, HBV DNA and RNA were significantly enhanced by 3-day 3,4,5-CQME treatment; it didn't directly affect intracellular cccDNA amount, although it slightly increased cccDNA accumulation as a HBV DNA replication feedback. In addition, treatment with 3,4,5-CQME significantly induced HBx protein expression for viral replication. We utilized a phospho-antibody assay to profile the signal transduction change by 3,4,5-CQME to illuminate its molecular mechanism. The results indicate that treatment with 3,4,5-CQME activated AKT/mTOR, MAPK and NF-κB pathways verified by immunoblot. Moreover, 3,4,5-CQME upregulated the expression of nuclear transcriptional factors PGC1α and PPARα. In short, 3,4,5-CQME promotes HBV transcription and replication by upregulating HBx expression and activating HBV transcriptional regulation-related signals. As caffeoylquinic acids are widely present in traditional Chinese medicines, the risk of intaking caffeoylquinic acids-containing herbs for hepatitis B treatment requires more evaluation and further research.