Yonglan Liu

Hepatitis B viral core protein disrupts human host gene expression by binding to promoter regions

BackgroundThe core protein (HBc) of hepatitis B virus (HBV) has been implicated in the malignant transformation of chronically-infected hepatocytes and displays pleiotropic functions, including RNA- and DNA-binding activities. However, the mechanism by which HBc interacts with the human genome to exert effects on hepatocyte function remains unknown. This study investigated the distribution of HBc binding to promoters in the human genome and evaluated its effects on the related genes’ expression.ResultsWhole-genome chromatin immunoprecipitation microarray (ChIP-on-chip) analysis was used to identify HBc-bound human gene promoters. Gene Ontology and pathway analyses were performed on related genes. The quantitative polymerase chain reaction assay was used to verify ChIP-on-chip results. Five novel genes were selected for luciferase reporter assay evaluation to assess the influence of HBc promoter binding. The HBc antibody immunoprecipitated approximately 3100 human gene promoters. Among these, 1993 are associated with known biological processes, and 2208 regulate genes with defined molecular functions. In total, 1286 of the related genes mediate primary metabolic processes, and 1398 encode proteins with binding activity. Sixty-four of the promoters regulate genes related to the mitogen-activated protein kinase (MAPK) pathways, and 41 regulate Wnt/beta-catenin pathway genes. The reporter gene assay indicated that HBc binding up-regulates proto-oncogene tyrosine-protein kinase (SRC), type 1 insulin-like growth factor receptor (IGF1R), and neurotrophic tyrosine kinase receptor 2 (NTRK2), and down-regulates v-Ha-ras Harvey rat sarcoma viral oncogene (HRAS).ConclusionHBc has the ability to bind a large number of human gene promoters, and can disrupt normal host gene expression. Manipulation of the transcriptional profile in HBV-infected hepatocytes may represent a key pathogenic mechanism of HBV infection.

Accuracy assessment of pharmacogenetic algorithms for warfarin dose prediction in Chinese patients

A few warfarin pharmacogenetic dosing algorithms have been proposed,based on multiethnic or homogeneous populations, to estimate warfarin therapeutic doses. However, it remains to be proven that which algorithm is accurate in predicting warfarin dose in Chinese people. We selected eight warfarin dose predictive pharmacogenetic algorithms and retrospectively assessed the predictive accuracy of each algorithm in a total of 368 eligible outpatients by comparing the actual stable therapeutic dose to the dose predicted by the algorithm. Our results showed that a high level of performance was demonstrated by three algorithms,Gage et al., Anderson et al., and Wu et al., having a similar performance in coefficient of determination (R2) and percentage of patients predicted dose within 20% of actual dose. The Gage et al. algorithm had the lowest mean absolute error (MAE). These results indicated that the algorithm by Gage et al. provided a more accurate prediction than did the others,which suggests that this pharmacogenetic algorithm might be used in clinical practice to guide rational administration of warfarin.