CUL4B通过促进HBx稳定来促进乙肝病毒复制。

CUL4B facilitates HBV replication by promoting HBx stabilization.

作者信息

Shan Haixia, Wang Bo, Zhang Xiaodong, Song Hui, Li Xi, Zou Yongxin, Jiang Baichun, Hu Huili, Dou Hao, Shao Changshun, Gao Lifen, Ma Chunhong, Yang Xiaoyun, Liang Xiaohong, Gong Yaoqin

机构信息

Key Laboratory for Experimental Teratology of the Ministry of Education, Key Laboratory of Infection and Immunity of Shandong Province and Department of Immunology, School of Basic Medical Sciences, Shandong University, Jinan 250012, China.

Department of Laboratory Diagnosis, Cangzhou Combination of Traditional Chinese and Western Medicine Hospital of Hebei Province, Cangzhou 061000, China.

出版信息

Cancer Biol Med. 2021 May 9;19(1):120-31. doi: 10.20892/j.issn.2095-3941.2020.0468.

DOI:10.20892/j.issn.2095-3941.2020.0468

PMID:33969670

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC8763003/

Abstract

OBJECTIVE

Hepatitis B virus (HBV) infection is a major public health problem worldwide. However, the regulatory mechanisms underlying HBV replication remain unclear. Cullin 4B-RING ubiquitin E3 ligase (CRL4B) is involved in regulating diverse physiological and pathophysiological processes. In our study, we aimed to explain the role of CUL4B in HBV infection.

METHODS

transgenic mice or conditional knockout mice, as well as liver cell lines with CUL4B overexpression or knockdown, were used to assess the role of CUL4B in HBV replication. Immunoprecipitation assays and immunofluorescence staining were performed to study the interaction between CUL4B and HBx. Cycloheximide chase assays and ubiquitination assays were performed to evaluate the half-life and the ubiquitination status of HBx.

RESULTS

The hydrodynamics-based hepatitis B model in transgenic or conditional knockout mice indicated that CUL4B promoted HBV replication ( < 0.05). Moreover, the overexpression or knockdown system in human liver cell lines validated that CUL4B increased HBV replication in an HBx-dependent manner. Importantly, immunoprecipitation assays and immunofluorescence staining showed an interaction between CUL4B and HBx. Furthermore, CUL4B upregulated HBx protein levels by inhibiting HBx ubiquitination and proteasomal degradation ( < 0.05). Finally, a positive correlation between CUL4B expression and HBV pgRNA level was observed in liver tissues from HBV-positive patients and HBV transgenic mice.

CONCLUSIONS

CUL4B enhances HBV replication by interacting with HBx and disrupting its ubiquitin-dependent proteasomal degradation. CUL4B may therefore be a potential target for anti-HBV therapy.

摘要

目的

乙型肝炎病毒（HBV）感染是全球主要的公共卫生问题。然而，HBV复制的调控机制仍不清楚。Cullin 4B-环指泛素E3连接酶（CRL4B）参与调节多种生理和病理生理过程。在我们的研究中，旨在阐明CUL4B在HBV感染中的作用。

方法

使用转基因小鼠或条件性敲除小鼠，以及CUL4B过表达或敲低的肝细胞系，评估CUL4B在HBV复制中的作用。进行免疫沉淀试验和免疫荧光染色以研究CUL4B与HBx之间的相互作用。进行环己酰亚胺追踪试验和泛素化试验以评估HBx的半衰期和泛素化状态。

结果

转基因或条件性敲除小鼠基于流体动力学的乙型肝炎模型表明，CUL4B促进HBV复制（<0.05）。此外，人肝细胞系中的过表达或敲低系统证实，CUL4B以HBx依赖的方式增加HBV复制。重要的是，免疫沉淀试验和免疫荧光染色显示CUL4B与HBx之间存在相互作用。此外，CUL4B通过抑制HBx泛素化和蛋白酶体降解上调HBx蛋白水平（<0.05）。最后，在HBV阳性患者和HBV转基因小鼠的肝组织中观察到CUL4B表达与HBV pgRNA水平之间呈正相关。