Diseases caused by viruses threaten the production industry and food safety of aquaculture which is a great animal protein source. Grass carp reovirus (GCRV) has caused tremendous loss, and the molecular function of viral proteins during infection needs further research, as for most aquatic viruses. In this study, interaction between GCRV major outer capsid protein VP4 and RIG-I, a critical viral RNA sensor, was screened out by GST pull-down, endogenous immunoprecipitation and subsequent LC-MS/MS, and then verified by co-IP and an advanced far-red fluorescence complementation system. VP4 was proved to bind to the CARD and RD domains of RIG-I and promoted K48-linked ubiquitination of RIG-I to degrade RIG-I. VP4 reduced mRNA and promoter activities of key genes of RLR pathway and sequential IFN production. As a consequence, antiviral effectors were suppressed and GCRV replication increased, resulting in intensified cytopathic effect. Furthermore, results of transcriptome sequencing of VP4 stably expressed CIK (C. idella kidney) cells indicated that VP4 activated the MyD88-dependent TLR pathway. Knockdown of VP4 obtained opposite effects. These results collectively revealed that VP4 interacts with RIG-I to restrain interferon response and assist GCRV invasion. This study lays the foundation for anti-dsRNA virus molecular function research in teleost and provides a novel insight into the strategy of immune evasion for aquatic virus.

Although aberrant microRNA (miRNA) expressions have been observed in different types of cancer, their pathophysiologic role and their relevance to tumorigenesis are still largely unknown. In this study, we first evaluated the expression of 308 miRNAs in human hepatocellular carcinoma (HCC) and normal hepatic tissues and identified 29 differentially expressed miRNAs in HCC tissues. miR-101, a significantly down-regulated miRNA, was further studied in greater detail because the signal pathway(s) regulated by miR-101 and the role of miR-101 in tumorigenesis have not yet been elucidated. Interestingly, decreased expression of miR-101 was found in all six hepatoma cell lines examined and in as high as 94.1% of HCC tissues, compared with their nontumor counterparts. Furthermore, ectopic expression of miR-101 dramatically suppressed the ability of hepatoma cells to form colonies in vitro and to develop tumors in nude mice. We also found that miR-101 could sensitize hepatoma cell lines to both serum starvation– and chemotherapeutic drug–induced apoptosis. Further investigation revealed that miR-101 significantly repressed the expression of luciferase carrying the 3′-untranslated region of Mcl-1 and reduced the endogenous protein level of Mcl-1, whereas the miR-101 inhibitor obviously up-regulated Mcl-1 expression and inhibited cell apoptosis. Moreover, silencing of Mcl-1 phenocopied the effect of miR-101 and forced expression of Mcl-1 could reverse the proapoptotic effect of miR-101. These results indicate that miR-101 may exert its proapoptotic function via targeting Mcl-1. Taken together, our data suggest an important role of miR-101 in the molecular etiology of cancer and implicate the potential application of miR-101 in cancer therapy. [Cancer Res 2009;69(3):1135–42]

Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are key long-chain omega-3 fatty acids in fish nutrition, but their differential effects on Atlantic salmon under unpredictable chronic stress (UCS) remain unclear. This study compared hepatic responses to DHA- and EPA-rich diets under unstressed and UCS conditions. Atlantic salmon post-smolts were fed a low-EPA+DHA, DHA-rich, or EPA-rich diet for 10 weeks, followed by 3 weeks of UCS. Liver transcriptomes were analyzed by RNA sequencing, and selected genes were validated by quantitative reverse transcription PCR. Growth did not differ among dietary groups. Under unstressed conditions, the DHA-rich diet induced more differentially expressed genes than the EPA-rich diet (67 vs. 29) and affected pathways related to fatty acid metabolism, autophagy, cholesterol homeostasis, and antioxidant defense. After UCS, the EPA-rich diet induced a broader hepatic transcriptional response than the DHA-rich diet (205 vs. 57 differentially expressed genes), with only 12 genes shared between the two comparisons. Both diets affected fatty acid- and steroid-biosynthesis-related pathways, while gene-level responses were diet-specific. These findings reveal distinct, stress-dependent hepatic responses to dietary DHA and EPA and may inform future optimization of their nutritional provision in Atlantic salmon production.