Repression of hepatitis B viral gene expression by transcription factor nuclear factor-kappaB

2009 ◽  
Vol 11 (4) ◽  
pp. 645-660 ◽  
Author(s):  
Yen-Cheng Lin ◽  
En-Chi Hsu ◽  
Ling-Pai Ting
2015 ◽  
Vol 89 (8) ◽  
pp. 4345-4355 ◽  
Author(s):  
Ruidong Hao ◽  
Jing He ◽  
Xing Liu ◽  
Guozhen Gao ◽  
Dan Liu ◽  
...  

ABSTRACTHepatitis B virus (HBV), a small enveloped DNA virus, chronically infects more than 350 million people worldwide and causes liver diseases from hepatitis to cirrhosis and liver cancer. Here, we report that hepatocyte nuclear factor 6 (HNF6), a liver-enriched transcription factor, can inhibit HBV gene expression and DNA replication. Overexpression of HNF6 inhibited, while knockdown of HNF6 expression enhanced, HBV gene expression and replication in hepatoma cells. Mechanistically, the SP2 promoter was inhibited by HNF6, which partly accounts for the inhibition on S mRNA. Detailed analysis showed that aciselement on the HBV genome (nucleotides [nt] 3009 to 3019) was responsible for the inhibition of the SP2 promoter by HNF6. Moreover, further analysis showed that HNF6 reduced viral pregenomic RNA (pgRNA) posttranscriptionally via accelerating the degradation of HBV pgRNA independent of La protein. Furthermore, by using truncated mutation experiments, we demonstrated that the N-terminal region of HNF6 was responsible for its inhibitory effects. Importantly, introduction of an HNF6 expression construct with the HBV genome into the mouse liver using hydrodynamic injection resulted in a significant reduction in viral gene expression and DNA replication. Overall, our data demonstrated that HNF6 is a novel host factor that can restrict HBV replication via both transcriptional and posttranscriptional mechanisms.IMPORTANCEHBV is a major human pathogen whose replication is regulated by host factors. Liver-enriched transcription factors are critical for many liver functions, including metabolism, development, and cell proliferation, and some of them have been shown to regulate HBV gene expression or replication in different manners. In this study, we showed that HNF6 could inhibit the gene expression and DNA replication of HBV via both transcriptional and posttranscriptional mechanisms. As HNF6 is differentially expressed in men and women, the current results may suggest a role of HNF6 in the gender dimorphism of HBV infection.


Cells ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1335
Author(s):  
Marina Mostafizar ◽  
Claudia Cortes-Pérez ◽  
Wanda Snow ◽  
Jelena Djordjevic ◽  
Aida Adlimoghaddam ◽  
...  

The transcription factor nuclear factor kappa B (NF-κB) is highly expressed in almost all types of cells. NF-κB is involved in many complex biological processes, in particular in immunity. The activation of the NF-κB signaling pathways is also associated with cancer, diabetes, neurological disorders and even memory. Hence, NF-κB is a central factor for understanding not only fundamental biological presence but also pathogenesis, and has been the subject of intense study in these contexts. Under healthy physiological conditions, the NF-κB pathway promotes synapse growth and synaptic plasticity in neurons, while in glia, NF-κB signaling can promote pro-inflammatory responses to injury. In addition, NF-κB promotes the maintenance and maturation of B cells regulating gene expression in a majority of diverse signaling pathways. Given this, the protein plays a predominant role in activating the mammalian immune system, where NF-κB-regulated gene expression targets processes of inflammation and host defense. Thus, an understanding of the methodological issues around its detection for localization, quantification, and mechanistic insights should have a broad interest across the molecular neuroscience community. In this review, we summarize the available methods for the proper detection and analysis of NF-κB among various brain tissues, cell types, and subcellular compartments, using both qualitative and quantitative methods. We also summarize the flexibility and performance of these experimental methods for the detection of the protein, accurate quantification in different samples, and the experimental challenges in this regard, as well as suggestions to overcome common challenges.


2002 ◽  
Vol 76 (6) ◽  
pp. 2721-2729 ◽  
Author(s):  
Gulam Waris ◽  
Aleem Siddiqui

ABSTRACT The signal transducer and activator of transcription 3 (STAT-3), a member of the STAT family of proteins, binds to a large number of transcriptional control elements and regulates gene expression in response to cytokines. While it binds to its cognate nucleotide sequences, it has been recently shown to directly interact with other transcriptional factors in the absence of DNA. We report here one such novel interaction between STAT-3 and hepatocyte nuclear factor 3 (HNF-3) in the absence of DNA. We have identified a STAT-3 binding site within the core domain of hepatitis B virus (HBV) enhancer 1. The HBV enhancer 1 DNA-STAT-3 protein interaction is shown to be stimulated by interleukin-6 (IL-6) and epidermal growth factor, which leads to an overall stimulation of HBV enhancer 1 function and viral gene expression. Using mobility shift assays and transient transfection schemes, we demonstrate a cooperative interaction between HNF-3 and STAT-3 in mediating the cytokine-mediated HBV enhancer function. Cytokine stimulation of HBV gene expression represents an important regulatory scheme of direct relevance to liver disease pathogenesis associated with HBV infection.


2010 ◽  
Vol 2010 ◽  
pp. 1-9 ◽  
Author(s):  
Anneleen Spooren ◽  
Krzysztof Kolmus ◽  
Linda Vermeulen ◽  
Karlien Van Wesemael ◽  
Guy Haegeman ◽  
...  

The transcription factor nuclear factor kappaB (NF-B) is one of the central mediators of inflammatory gene expression. Several posttranslational modifications of NF-B, regulating its transactivation ability, have been described. Especially phosphorylation of the NF-B subunit p65 has been investigated in depth and several commercial phosphospecific antibodies, targeting selected p65 residues, are available. One of the p65 residues, that is subject to phosphorylation by protein kinase A (PKA) as well as by mitogen-stimulated kinase-1 (MSK-1), is the serine at position 276. Here, we have performed a detailed analysis of the performance of the most commonly used commercial anti-P-p65 Ser276 antibodies. Our findings indicate that at least three widely used anti-P-p65 Ser276 antibodies do not detect p65 in vivo via Western Blot, but instead crossreact with PKA-regulated proteins. As PKA is one of the main kinases responsible for phosphorylation of p65 at Ser276, this observation warrants cautious interpretation of data generated using the tested antibodies.


2015 ◽  
Vol 90 (1) ◽  
pp. 486-496 ◽  
Author(s):  
Xiuji Cui ◽  
Daniel N. Clark ◽  
Kuancheng Liu ◽  
Xiao-Dong Xu ◽  
Ju-Tao Guo ◽  
...  

ABSTRACTHepatitis B virus (HBV) infects hundreds of millions of people worldwide and causes acute and chronic hepatitis, cirrhosis, and hepatocellular carcinoma. HBV is an enveloped virus with a relaxed circular (RC) DNA genome. In the nuclei of infected human hepatocytes, conversion of RC DNA from the incoming virion or cytoplasmic mature nucleocapsid (NC) to the covalently closed circular (CCC) DNA, which serves as the template for producing all viral transcripts, is essential to establish and sustain viral replication. A prerequisite for CCC DNA formation is the uncoating (disassembly) of NCs to expose their RC DNA content for conversion to CCC DNA. We report here that in an immortalized mouse hepatocyte cell line, AML12HBV10, in which RC DNA exposure is enhanced, the exposed viral DNA could trigger an innate immune response that was able to modulate viral gene expression and replication. When viral gene expression and replication were low, the innate response initially stimulated these processes but subsequently acted to shut off viral gene expression and replication after they reached peak levels. Inhibition of viral DNA synthesis or cellular DNA sensing and innate immune signaling diminished the innate response. These results indicate that HBV DNA, when exposed in the host cell cytoplasm, can function to trigger an innate immune response that, in turn, modulates viral gene expression and replication.IMPORTANCEChronic infection by hepatitis B virus (HBV) afflicts hundreds of millions worldwide and is sustained by the episomal covalently closed circular (CCC) DNA in the nuclei of infected hepatocytes. Release of viral genomic DNA from cytoplasmic nucleocapsids (NCs) (NC disassembly or uncoating) is a prerequisite for its conversion to CCC DNA, which can also potentially expose the viral DNA to host DNA sensors and trigger an innate immune response. We have found that in an immortalized mouse hepatocyte cell line in which efficient CCC DNA formation was associated with enhanced exposure of nucleocapsid-associated DNA, the exposed viral DNA indeed triggered host cytoplasmic DNA sensing and an innate immune response that was able to modulate HBV gene expression and replication. Thus, HBV can, under select conditions, be recognized by the host innate immune response through exposed viral DNA, which may be exploited therapeutically to clear viral persistence.


2007 ◽  
Vol 14 (6) ◽  
pp. 731-744 ◽  
Author(s):  
En-Chi Hsu ◽  
Yen-Cheng Lin ◽  
Chia-Shia Hung ◽  
Chiu-Jung Huang ◽  
Mei-Yi Lee ◽  
...  

Hepatology ◽  
1992 ◽  
Vol 16 (1) ◽  
pp. 13-18 ◽  
Author(s):  
Chen-Kung Chou ◽  
Li-Hsien Wang ◽  
Hsing-Mei Lin ◽  
Chin-Wen Chi

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