Peretinoin, an Acyclic Retinoid, Inhibits Hepatitis B Virus Replication by Suppressing Sphingosine Metabolic Pathway In Vitro.

Kazuhisa Murai,Natsumi Shirasaki,Saki Nakasho,Masao Honda,Hikari Okada,Taro Yamashita,Shuichi Kaneko,Yoshio Sakai,Takayoshi Shirasaki,Tetsuro Shimakami,Ryogo Shimizu

doi:10.3390/ijms19020108

Kazuhisa Murai, Natsumi Shirasaki + Show 9 more

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https://doi.org/10.3390/ijms19020108

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Abstract

Hepatocellular carcinoma (HCC) frequently develops from hepatitis C virus (HCV) and hepatitis B virus (HBV) infection. We previously reported that peretinoin, an acyclic retinoid, inhibits HCV replication. This study aimed to examine the influence of peretinoin on the HBV lifecycle. HBV-DNA and covalently closed circular DNA (cccDNA) were evaluated by a qPCR method in HepG2.2.15 cells. Peretinoin significantly reduced the levels of intracellular HBV-DNA, nuclear cccDNA, and HBV transcript at a concentration that did not induce cytotoxicity. Conversely, other retinoids, such as 9-cis, 13-cis retinoic acid (RA), and all-trans-retinoic acid (ATRA), had no effect or rather increased HBV replication. Mechanistically, although peretinoin increased the expression of HBV-related transcription factors, as observed for other retinoids, peretinoin enhanced the binding of histone deacetylase 1 (HDAC1) to cccDNA in the nucleus and negatively regulated HBV transcription. Moreover, peretinoin significantly inhibited the expression of SPHK1, a potential inhibitor of HDAC activity, and might be involved in hepatic inflammation, fibrosis, and HCC. SPHK1 overexpression in cells cancelled the inhibition of HBV replication induced by peretinoin. This indicates that peretinoin activates HDAC1 and thereby suppresses HBV replication by inhibiting the sphingosine metabolic pathway. Therefore, peretinoin may be a novel therapeutic agent for HBV replication and chemoprevention against HCC.

Highlights

Hepatitis B virus (HBV) infection is the major cause of hepatocellular carcinoma (HCC), and 350 million people worldwide are chronic carriers of HBV [1]
We demonstrate that peretinoin inhibits HBV replication by reducing the mRNA and protein levels of sphingosine kinase 1 (SPHK1) and its transcription factor, Egr-1, which leads to the recruitment of histone deacetylase 1 (HDAC1) to closed circular DNA (cccDNA)
The time-dependent effect on HBV replication showed that peretinoin concentrations of 25 and 50 μM inhibited HBV replication from the start of the experiment (Day 1; Figure 1D,E), with no cellular cytotoxicity observed at this point (Figure 1F)

Summary

Introduction

Hepatitis B virus (HBV) infection is the major cause of hepatocellular carcinoma (HCC), and 350 million people worldwide are chronic carriers of HBV [1]. Nucleos(t)ide analog (NA) therapy for chronic hepatitis B patients has been effective in suppressing HBV replication; NA could not completely eliminate HBV covalently closed circular DNA (cccDNA) in the nucleus [2]. Novel antiviral agents targeting cccDNA are required to cure HBV infection. Larger-scale clinical trials are ongoing in various countries to confirm its clinical efficacy in preventing HCC associated with HBV and HCV after curative treatment. We reported that peretinoin prevented the development of hepatic fibrosis and tumors using a platelet-derived growth factor (PDGF)-C transgenic mouse model [5]. We reported that peretinoin inhibited HCV replication and virus release by altering intracellular lipid metabolism [6]. The importance of the peretinoin in HBV replication remains poorly understood

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