Hepatitis B Virus (HBV) X protein (HBx) is known to be involved in the initiation and progression of hepatocellular carcinoma (HCC) through modulation of host gene response. Alterations in miRNA expressions are frequently noted in HCC. This study is aimed to examine the role of HBx protein in the modulation of oncogenic miRNA-21, miRNA-222 and tumor suppressor miRNA-145 in malignant hepatocytes. Expressions of miRNA-21, miRNA-222 and miRNA-145 were measured in HepG2 cells transfected with HBx-plasmid (genotype D) and with full length HBV genome (genotype D) and also in stably HBV producing HepG2.2.15 cells using real time PCR. Their target mRNAs and proteins - PTEN, p27 and MAP3K - were analyzed by real time PCR and western blot respectively. miRNA expressions were measured after HBx/D mRNA specific siRNA treatment. The expressions of these miRNAs were analyzed in liver cirrhosis and HCC patients also. The study revealed a down-regulation of miRNA-21 and miRNA-222 expressions in HBx transfected HepG2 cells, pUC-HBV 1.3 plasmid transfected HepG2 cells as well as in HepG2.2.15 cells. Down regulation of miRNA-21 and miRNA-222 expression was observed in patient serum samples. Down regulation of miRNA-145 expression was observed in HepG2 cells transiently transfected with HBx and pUC-HBV1.3 plasmid as well as in patient samples but the expression of miRNA-145 was increased in HepG2.2.15 cells. Target mRNA and protein expressions were modulated in HepG2 cells and in HepG2.2.15 cell line consistent with the modulation of miRNA expressions. Thus, HBx protein differentially modulated the expression of miRNAs. The study throws light into possible way by which HBx protein acts through microRNA and thereby regulates host functioning. It might suggest new therapeutic strategies against hepatic cancer.

Background: Occult hepatitis B virus (HBV) infection might transmit viremic units into the public blood supply if only hepatitis B surface antigen (HBsAg) testing is used for donor screening. Our aim was to evaluate the prevalence of occult HBV infection among the HBsAg negative/antiHBc positive donations from a highly HIV prevalent region of India. Methods: A total of 729 HBsAg negative donor units were included in this study. Surface gene and precore region were amplified by in house nucleic acid test (NAT) for detection of occult HBV infection and surface gene was analyzed after direct sequencing. Results: A total of 220 (30.1%) HBsAg negative donors were antiHBc positive, of them 66 (30%) were HBV DNA positive by NAT. HBV DNA positivity among 164 antiHBc only group, was 27.1% and among 40 antiHBs positive group was 30.0%. HBV/D (93.3%) was predominant and prevalence of both HBV/C and HBV/A was 3.3%. Single or multiple amino acids substitutions were found in 95% samples. Conclusion: Thus, a considerable number of HBV infected donors remain undiagnosed, if only HBsAg is used for screening. Addition of antiHBc testing for donor screening, although will lead to rejection of a large number of donor units, will definitely eliminate HBV infected donations and help in reducing HBV transmission with its potential consequences, especially among the immunocompromised population. The HBV genetic diversity found in this donor population are in accordance with other parts of India.

Promyelocytic leukemia nuclear bodies (PML-NB) are sub-nuclear organelles that are the hub of numerous proteins. DNA/RNA viruses often hijack the cellular factors resident in PML-NBs to promote their proliferation in host cells. Hepatitis B virus (HBV), belonging to Hepadnaviridae family, remains undetected in early infection as it does not induce the innate immune response and is known to be the cause of several hepatic diseases leading to cirrhosis and hepatocellular carcinoma. The association of PML-NB proteins and HBV is being addressed in a number of recent studies. Here, we report that the PML-NB protein Speckled 110 kDa (Sp110) is SUMO1-modified and undergoes a deSUMOylation-driven release from the PML-NB in the presence of HBV. Intriguingly, Sp110 knockdown significantly reduced viral DNA load in the culture supernatant by activation of the type I interferon-response pathway. Furthermore, we found that Sp110 differentially regulates several direct target genes of hepatitis B virus protein X (HBx), a viral co-factor. Subsequently, we identified Sp110 as a novel interactor of HBx and found this association to be essential for the exit of Sp110 from the PML-NB during HBV infection and HBx recruitment on the promoter of these genes. HBx, in turn, modulates the recruitment of its associated transcription cofactors p300/HDAC1 to these co-regulated genes, thereby altering the host gene expression program in favor of viral persistence. Thus, we report a mechanism by which HBV can evade host immune response by hijacking the PML-NB protein Sp110, and therefore, we propose it to be a novel target for antiviral therapy.

Hepatitis B virus (HBV) attacks the liver and can cause both acute as well as chronic liver diseases which might lead to liver cirrhosis and hepatocellular carcinoma. Regardless of the availability of a vaccine and numerous treatment options, HBV is a major cause of morbidity and mortality across the world. Recently,microRNAs (miRNAs) have emerged as important modulators of gene function. Studies on the role of miRNA in the regulation of hepatitis B virus gene expression have been the focus of modern antiviral research. miRNAs can regulate viral replication and pathogenesis in a number of different ways, which includefacilitation, direct or indirect inhibition, activation of immune response, epigenetic modulation, etc. Nevertheless, these mechanisms can appropriately be used with a diagnosticand/or therapeutic approach. The present review is an attempt to classify specific miRNAs that are reported to be associated with various aspects of hepatitis B biology, in order to precisely present the participation of individual miRNAs in multiple aspects relating to HBV.