Lifestyle-related diseases of the digestive system: a new in vitro model of hepatitis C virion production: application of basic research on hepatitis C virus to clinical medicine

Q63, a novel DENV2 RdRp non-nucleoside inhibitor, inhibited DENV2 replication and infection

Dengue virus (DENV) annually infects 400 million people worldwide. Unfortunately, there is lack of widely protective vaccine or drugs against DENV. The viral RNA-dependent RNA polymerase (RdRp) of NS5 protein is highly conserved among different DENV subtypes, thus presenting itself as an attractive target for drug design. In the current research, SPRi was performed to screen compounds against DENV2 RdRp and 5(1H)-Quinazolinone,2-(4-bromophenyl)-2,3,4,6,7,8-hexahydro-7,7-dimethyl-1,3-diphenyl (Q63) was successfully screened out with a KD of 0.9 μM. Then, ITC and molecular docking assay was performed to access the binding mechanism between Q63 and DENV2 RdRp. Meanwhile, Q63 also decreased the intermediate dsRNA production, which was the product of RdRp. Further the antiviral effects of Q63 were evaluated on mosquito C6/36 cells and mammalian BHK-21 cells. Q63 reduced CPE and cell toxicity effect after DENV2 infection on C6/36 and BHK-21 cells, with an EC₅₀ of 2.08 μM. Time of addition assay revealed that Q63 affected the early genome RNA replication stage, including genome RNA replication. In addition, Q63 down-regulated STAT1 phosphorylation, ISG15 and ISG54 after DENV2 infection. In summary, Q63 was found to be a novel RdRp non-nucleoside inhibitor and a potential lead compound for coping with DENV infectious disease in the future.

Genetic Dissection of the Host Tropism of Human-Tropic Pathogens

Infectious diseases are the second leading cause of death worldwide. Although the host multitropism of some pathogens has rendered their manipulation possible in animal models, the human-restricted tropism of numerous viruses, bacteria, fungi, and parasites has seriously hampered our understanding of these pathogens. Hence, uncovering the genetic basis underlying the narrow tropism of such pathogens is critical for understanding their mechanisms of infection and pathogenesis. Moreover, such genetic dissection is essential for the generation of permissive animal models that can serve as critical tools for the development of therapeutics or vaccines against challenging human pathogens. In this review, we describe different experimental approaches utilized to uncover the genetic foundation regulating pathogen host tropism as well as their relevance for studying the tropism of several important human pathogens. Finally, we discuss the current and future uses of this knowledge for generating genetically modified animal models permissive for these pathogens.

Treatment options for hepatitis C and the rationale for low response rates in African Americans

Hepatitis C virus (HCV), the leading cause for liver transplantation, is emerging as1 of the infections that pose public health problems in the world since about 170 million people worldwide are infected with this virus. Inequality in addressing racial/ethnic disparities in treatment for hepatitis C is a pressing problem. HCV is more common among African Americans than among other racial groups in the United States. Although African Americans have been shown to have a lower rate of viral clearance and a higher rate of chronic hepatitis C, they may have at the same time a much lower rate of fibrosis progression compared to Caucasians. The purpose of this study is to summarize treatment options available for hepatitis C in African Americans and to describe the different mechanisms thought to be the reasons for the disparate response to treatment in African Americans.

A recombinant replication-competent hepatitis C virus expressing Azami-Green, a bright green-emitting fluorescent protein, suitable for visualization of infected cells

The hepatitis C virus (HCV) production system consists of transfecting the human hepatoma cell line Huh7 with genomic HCV RNA (JFH1). To monitor HCV replication by fluorescence microscopy, we constructed a recombinant HCV clone expressing Azami-Green (mAG), a bright green fluorescent protein, by inserting the mAG gene into the nonstructural protein 5A (NS5A) gene; the resultant clone was designated JFH1-hmAG. The Huh-7.5.1 (a subclone of Huh7) cells transfected with JFH1-hmAG RNA were found to produce cytoplasmic NS5A-mAG, as readily visualized by fluorescence microscopy, and infectious virus, as assayed with the culture supernatant, indicating that JFH1-hmAG is infectious and replication-competent. Furthermore, the replication of this virus was inhibited by interferon alpha in a dose-dependent manner. These results suggest that JFH1-hmAG is useful for studying HCV life cycle and the mechanism of interferon's anti-HCV action and for screening and testing new anti-HCV drugs.