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The role of hepatitis B virus (HBV) X protein (HBx) in the regulation of HBV replication remains controversial. In the present study, the role of HBx in regulating HBV replication was initially investigated in both HepG2 and Huh7 in vitro cell lines with a transient transfection system. Next, the regions of HBx responsible for transcriptional transactivation and promotion of HBV replication were mapped in an HBV replication mouse model by in vivo transfection of a series of HBx expression plasmids. In an in vitro setting, HBx deficiency had little effect on HBV replication in Huh7 cells, but impaired HBV replication in HepG2 cells. In an in vivo setting, HBx had a strong enhancing effect on HBV transcription and replication. For the C-terminal two-thirds of the protein (amino acids [aa] 51 to 154) was required for this function of HBx, and the regions spanning aa 52 to 72 and 88 to 154 were found to be important for the stimulatory function of HBx on HBV replication. In conclusion, the role of HBx in HBV replication regulation is affected by host cell type, and HBx has an important role in stimulating HBV transcription and replication in hepatocytes in vivo. Further, the transcriptional transactivation function of HBx may be crucial for its stimulatory effect on HBV transcription and replication.

BackgroundAngiogenesis is a pathobiological hallmark of gastric cancer. However, rare studies focus on angiogenesis in gastric precancerous lesions (GPL). Weipixiao (WPX), a Chinese herbal preparation, is proved clinically effective in treating GPL. Here, we evaluated WPX’s anti-angiogenic potential for GPL, and also investigated the possibility of its anti-angiogenic mechanisms.MethodsHPLC analysis was applied to screen the major chemical components of WPX. After modeling N-methyl-N′-nitro-N-nitrosoguanidine (MNNG)-induced GPL in male Sprague-Dawley rats, different doses of WPX were administrated orally for 10 weeks. Next, we performed histopathological examination using routine H&E staining and HID-AB-PAS staining. In parallel, we assessed angiogenesis revealed by microvessel density (MVD) using CD34 immunostaining, and subsequently observe microvessel ultrastructure in gastric mucosa under Transmission Electron Microscope. Finally, we detect expression of angiogenesis-associated markers VEGF and HIF-1α using immunohistochemistry. Moreover, mRNA expressions of ERK1, ERK2, Cylin D1 as well as HIF-1α in gastric mucosa were determined by quantitative real-time reverse transcription- polymerase chain reaction.ResultsWe observed the appearance of active angiogenesis in GPL rats, and demonstrated that WPX could reduce microvascular abnormalities and attenuate early angiogenesis in most of GPL specimens with a concomitant regression of most intestinal metaplasia (IM) and a portion of gastric epithelial dysplasia (GED). In parallel, WPX could suppress HIF-1α mRNA expression (P < 0.01) as well as protein expression (although without statistical significance), and could markedly inhibit VEGF protein expression in GPL rats. Mechanistically, WPX intervention, especially at low dose, caused a significant decrease in the ERK1 and Cylin D1 mRNA levels. However, WPX might probably have no regulatory effect on ERK2 amplification.ConclusionsWPX could attenuate early angiogenesis and temper microvascular abnormalities in GPL rats. This might be partly achieved by inhibiting on the angiogenesis-associated markers HIF-1α and VEGF, and on the ERK1/Cylin D1 aberrant activation.Electronic supplementary materialThe online version of this article (10.1186/s12906-018-2309-3) contains supplementary material, which is available to authorized users.

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