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Published on: December 21, 2019
Discovery and mechanistic study of Imperatorin that inhibits HBsAg expression and cccDNA transcription
Fang Ren1,2, Shiqiao Zhao1,2, Xin He3
1Department of Clinical Laboratory, Chongqing Hospital of Traditional Chinese Medicine, Chongqing, China.
Insights
Imperatorin, a natural compound, effectively inhibits hepatitis B surface antigen (HBsAg) and covalently closed circular DNA (cccDNA) transcription. This compound targets the ERK-CREB pathway, offering a potential new treatment for chronic hepatitis B virus (HBV) infection.
Area of Science:
- Virology
- Pharmacology
- Natural Products Chemistry
Background:
- Chronic hepatitis B virus (HBV) infection is a major global health concern, leading to cirrhosis and hepatocellular carcinoma (HCC).
- Current treatments inadequately suppress hepatitis B surface antigen (HBsAg) and covalently closed circular DNA (cccDNA), necessitating novel therapeutic strategies.
- Disrupting HBsAg production from cccDNA is crucial for effective HBV management.
Purpose of the Study:
- To identify natural compounds that inhibit HBsAg expression from cccDNA.
- To investigate the therapeutic potential and mechanism of action of Imperatorin against HBV infection.
- To explore Imperatorin's effects on cccDNA transcription and viral markers in vitro and in vivo.
Main Methods:
- Screening of natural compounds from Chinese herbal medicines using ELISA and qRT-PCR.
- Pharmacodynamic studies in HBV-infected HepG2-NTCP cells, primary human hepatocytes (PHHs), and a humanized mouse model.
- Proteome analysis, molecular docking, and bio-layer interferometry (BLI) to elucidate the mechanism of action.
- Assessment of HBsAg, HBV RNAs, HBV DNA, and cccDNA transcriptional activity.
Main Results:
- Imperatorin significantly inhibited HBsAg expression and cccDNA transcriptional activity.
- Imperatorin reduced HBV RNAs and HBV DNA levels both in vitro and in vivo.
- Mechanistic studies revealed Imperatorin directly binds to ERK, inhibiting the ERK-CREB pathway crucial for HBV transcription.
- The antiviral effect of Imperatorin was dependent on ERK presence.
Conclusions:
- Imperatorin demonstrates potent antiviral activity against chronic HBV infection.
- Imperatorin effectively suppresses HBsAg production and cccDNA transcription via the ERK-CREB signaling pathway.
- Imperatorin represents a promising natural compound candidate for developing new HBV therapeutics.
Abstract:
Chronic hepatitis B virus (HBV) infection remains a significant global health challenge due to its link to severe conditions like HBV-related cirrhosis and hepatocellular carcinoma (HCC). Although current treatments effectively reduce viral levels, they have limited impact on certain HBV elements, namely hepatitis B surface antigen (HBsAg) and covalently closed circular DNA (cccDNA). This highlights the urgent need for innovative pharmaceutical and biological interventions that can disrupt HBsAg production originating from cccDNA. In this study, we identified a natural furanocoumarin compound, Imperatorin, which markedly inhibited the expression of HBsAg from cccDNA, by screening a library of natural compounds derived from Chinese herbal medicines using ELISA assay and qRT-PCR. The pharmacodynamics study of Imperatorin was explored on HBV infected HepG2-NTCP/PHHs and HBV-infected humanized mouse model. Proteome analysis was performed on HBV infected HepG2-NTCP cells following Imperatorin treatment. Molecular docking and bio-layer interferometry (BLI) were used for finding the target of Imperatorin. Our findings demonstrated Imperatorin remarkably reduced the level of HBsAg, HBV RNAs, HBV DNA and transcriptional activity of cccDNA both in vitro and in vivo. Additionally, Imperatorin effectively restrained the actions of HBV promoters responsible for cccDNA transcription. Mechanistic study revealed that Imperatorin directly binds to ERK and subsequently interfering with the activation of CAMP response element-binding protein (CREB), a crucial transcriptional factor for HBV and has been demonstrated to bind to the PreS2/S and X promoter regions of HBV. Importantly, the absence of ERK could nullify the antiviral impact triggered by Imperatorin. Collectively, the natural compound Imperatorin may be an effective candidate agent for inhibiting HBsAg production and cccDNA transcription by impeding the activities of HBV promoters through ERK-CREB axis.
