Recent functional genomics studies including genome-wide small interfering RNA (siRNA) screens demonstrated that hepatitis C virus (HCV) exploits an extensive network of host factors for productive infection and propagation. How these co-opted host functions interact with various steps of HCV replication cycle and exert pro- or antiviral effects on HCV infection remains largely undefined. Here we present an unbiased and systematic strategy to functionally interrogate HCV host dependencies uncovered from our previous infectious HCV (HCVcc) siRNA screen. Applying functional genomics approaches and various in vitro HCV model systems, including HCV pseudoparticles (HCVpp), single-cycle infectious particles (HCVsc), subgenomic replicons, and HCV cell culture systems (HCVcc), we identified and characterized novel host factors or pathways required for each individual step of the HCV replication cycle. Particularly, we uncovered multiple HCV entry factors, including E-cadherin, choline kinase α, NADPH oxidase CYBA, Rho GTPase RAC1 and SMAD family member 6. We also demonstrated that guanine nucleotide binding protein GNB2L1, E2 ubiquitin-conjugating enzyme UBE2J1, and 39 other host factors are required for HCV RNA replication, while the deubiquitinating enzyme USP11 and multiple other cellular genes are specifically involved in HCV IRES-mediated translation. Families of antiviral factors that target HCV replication or translation were also identified. In addition, various virologic assays validated that 66 host factors are involved in HCV assembly or secretion. These genes included insulin-degrading enzyme (IDE), a proviral factor, and N-Myc down regulated Gene 1 (NDRG1), an antiviral factor. Bioinformatics meta-analyses of our results integrated with literature mining of previously published HCV host factors allows the construction of an extensive roadmap of cellular networks and pathways involved in the complete HCV replication cycle. This comprehensive study of HCV host dependencies yields novel insights into viral infection, pathogenesis and potential therapeutic targets.

Purpose: Persistent interleukin-8 (IL-8) production contributes to chronic inflammation of the stomach. The proinflammatory IL-1h polymorphisms, which enhance the cytokine production, are associated with increased risk of gastric cancer. The À251A/T polymorphism of the IL-8 promoter is involved in several human diseases. Particularly, the À251A is associated with decreased risk of colorectal cancer. We aimed to determine whether the À251 allele resulting in high IL-8 expression was associated with increased risk of gastric carcinoma. Experimental Design: The À251A/T promoters were cloned and analyzed by luciferase assay. Binding of nuclear proteins to the À251A/T promoters was analyzed by electrophoretic mobility shift assay.The À251A/T promoters were differentiated by PCR-RFLP. Comparison of gastric cancer risk between the À251A/T promoters was done by a case-control study. Results:The À251Tallele possessed transcriptional activity 2-to 5-fold stronger than the À251A counterpart. Electrophoretic mobility shift assay showed that the À251A promoter had strong ability to bind to an unknown protein or multiprotein complex. The À251T allele was associated with increased risk of noncardia (P trend = 0.012) and cardia (P trend = 0.029) carcinomas. Gastric carcinoma patients with the low-risk AA genotype had a tendency to sustain intestinal-type carcinomas (m 2 = 6.816; P = 0.033); however, the high-risk À251Tallele was associated with >2-fold increased risk of diffuse-type (AA versus AT + TT: odds ratio, 2.52; 95% confidence interval,1.16-5.49; P = 0.017) and mixed-type (AA versus AT + TT: odds ratio, 2.22; 95% confidence interval, 1.12-4.40; P = 0.019) carcinomas. Conclusions:The IL-8 À251Tallele is significantly associated with increased risk of gastric carcinoma, particularly the diffuse and mixed types in Chinese population.

BackgroundAlthough many studies have attempted to clarify the association between hepatitis B virus (HBV) infection and fatty liver disease, no prior studies have emphasized the relationship of HBV and fatty liver regarding different demographics of age and body mass index (BMI).AimTo investigate the correlation of HBV and fatty liver in the different demographics of age and BMI.MethodsWe enrolled consecutive subjects who had received health check-up services at the Taipei Veterans General Hospital from 2002 to 2009 and ultrasonography was used to diagnose fatty liver according to the practice guidelines of the American Gastroenterological Association.ResultsAmong the 33,439 subjects enrolled in this study, fatty liver was diagnosed in 43.9% of the population and 38.9% of patients with chronic HBV infection. Multivariate analysis showed that BMI, age, waist circumference, systolic blood pressure, fasting glucose, cholesterol, alanine aminotransferase (ALT) levels, and platelet counts were positively associated, while hepatitis B surface antigen (HBsAg) positivity was inversely associated with fatty liver, especially for subjects with BMI>22.4 kg/m2 and age>50 years. On the contrary, HBV infection was positively correlated with the presence of elevated serum ALT levels in subjects with fatty liver disease regardless of their age and BMI.ConclusionsMetabolic factors are important determinants for the prevalence of fatty liver. Patients with HBV infection were inversely associated with fatty liver disease than the general population, especially in older and obese patients. Furthermore, metabolic factors and HBV infection were associated with elevated serum ALT levels in fatty liver disease.