State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China.
Key Laboratory of Virology of Guangzhou, Institute of Medical Microbiology, Jinan University, Guangzhou, China.
J Virol. 2019 Mar 21;93(7). doi: 10.1128/JVI.01607-18. Print 2019 Apr 1.
Hepatitis B virus (HBV) infection is the leading cause of chronic hepatitis B (CHB), liver cirrhosis (LC), and hepatocellular carcinoma (HCC). This study reveals a distinct mechanism underlying the regulation of HBV replication. HBV activates homeobox A10 (HoxA10) in human hepatocytes, leukocytes, peripheral blood mononuclear cells (PBMCs), HepG2-NTCP cells, leukocytes isolated from CHB patients, and HBV-associated HCC tissues. HoxA10 in turn represses HBV replication in human hepatocytes, HepG2-NTCP cells, and BALB/c mice. Interestingly, we show that during early HBV infection, p38 mitogen-activated protein kinase (MAPK) and signal transducer and activator of transcription 3 (STAT3) were activated to facilitate HBV replication; however, during late HBV infection, HoxA10 was induced to attenuate HBV replication. Detailed studies reveal that HoxA10 binds to p38 MAPK, recruits SH2-containing protein tyrosine phosphatase 1 (SHP-1) to facilitate SHP-1 in catalyzing dephosphorylation of p38 MAPK/STAT3, and thereby attenuates p38 MAPK/STAT3 activation and HBV replication. Furthermore, HoxA10 binds to the HBV enhancer element I (EnhI)/X promoter, competes with STAT3 for binding of the promoter, and thereby represses HBV transcription. Taken together, these results show that HoxA10 attenuates HBV replication through repressing the p38 MAPK/STAT3 pathway by two approaches: HoxA10 interacts with p38 MAPK and recruits SHP-1 to repress HBV replication, and HoxA10 binds to the EnhI/X promoter and competes with STAT3 to attenuate HBV transcription. Thus, the function of HoxA10 is similar to the action of interferon (IFN) in terms of inhibition of HBV infection; however, the mechanism of HoxA10-mediated repression of HBV replication is different from the mechanism underlying IFN-induced inhibition of HBV infection. Two billion people have been infected with HBV worldwide; about 240 million infected patients developed chronic hepatitis B (CHB), and 650,000 die each year from liver cirrhosis (LC) or hepatocellular carcinoma (HCC). This work elucidates a mechanism underlying the control of HBV replication. HBV infection activates HoxA10, a regulator of cell differentiation and cancer progression, in human cells and patients with CHB and HCC. HoxA10 subsequently inhibits HBV replication in human tissue culture cells and mice. Additionally, HoxA10 interacts with p38 MAPK to repress the activation of p38 MAPK and STAT3 and recruits and facilitates SHP-1 to catalyze the dephosphorylation of p38 MAPK and STAT3. Moreover, HoxA10 competes with STAT3 for binding of the HBV X promoter to repress HBV transcription. Thus, this work reveals a negative regulatory mechanism underlying the control of HBV replication and provides new insights into the development of potential agents to control HBV infection.
乙型肝炎病毒 (HBV) 感染是慢性乙型肝炎 (CHB)、肝硬化 (LC) 和肝细胞癌 (HCC) 的主要原因。本研究揭示了调节 HBV 复制的独特机制。HBV 在人肝细胞、白细胞、外周血单核细胞 (PBMC)、HepG2-NTCP 细胞、CHB 患者分离的白细胞和 HBV 相关 HCC 组织中激活同源盒 A10 (HoxA10)。HoxA10 反过来抑制人肝细胞、HepG2-NTCP 细胞和 BALB/c 小鼠中的 HBV 复制。有趣的是,我们表明在早期 HBV 感染期间,p38 丝裂原活化蛋白激酶 (MAPK) 和信号转导和转录激活因子 3 (STAT3) 被激活以促进 HBV 复制;然而,在晚期 HBV 感染期间,诱导 HoxA10 以减弱 HBV 复制。详细研究表明,HoxA10 与 p38 MAPK 结合,募集含 SH2 的蛋白酪氨酸磷酸酶 1 (SHP-1) 以促进 SHP-1 催化 p38 MAPK/STAT3 的去磷酸化,从而减弱 p38 MAPK/STAT3 的激活和 HBV 复制。此外,HoxA10 与 HBV 增强子元件 I (EnhI)/X 启动子结合,与 STAT3 竞争结合启动子,从而抑制 HBV 转录。总之,这些结果表明 HoxA10 通过两种方式通过抑制 p38 MAPK/STAT3 途径来减弱 HBV 复制:HoxA10 与 p38 MAPK 相互作用并募集 SHP-1 以抑制 HBV 复制,以及 HoxA10 与 EnhI/X 启动子结合并与 STAT3 竞争以抑制 HBV 转录。因此,HoxA10 的功能类似于干扰素 (IFN) 在抑制 HBV 感染方面的作用;然而,HoxA10 介导的 HBV 复制抑制的机制与 IFN 诱导的抑制 HBV 感染的机制不同。全世界有 20 多亿人感染了 HBV;约 2.4 亿感染患者发展为慢性乙型肝炎 (CHB),每年有 65 万人死于肝硬化 (LC) 或肝细胞癌 (HCC)。这项工作阐明了控制 HBV 复制的机制。HBV 感染激活了人细胞和 CHB 和 HCC 患者中的细胞分化和癌症进展调节剂 HoxA10。随后,HoxA10 在人组织培养细胞和小鼠中抑制 HBV 复制。此外,HoxA10 与 p38 MAPK 相互作用,抑制 p38 MAPK 和 STAT3 的激活,并募集和促进 SHP-1 催化 p38 MAPK 和 STAT3 的去磷酸化。此外,HoxA10 与 STAT3 竞争结合 HBV X 启动子以抑制 HBV 转录。因此,这项工作揭示了控制 HBV 复制的负调节机制,并为开发控制 HBV 感染的潜在药物提供了新的见解。