Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been discovered as the pathogenic cause of the coronavirus disease 19 (COVID-19). Cellular entry of SARS-CoV-2 are mediated by the spike glycoprotein of virus, and the host specific receptors and proteases. Recently, besides pulmonary complications as the chief symptom, investigations have also revealed that SARS-CoV-2 can trigger neurological manifestations. Herein, to investigate the expression level of receptors and related proteases is important for understanding the neuropathy in COVID-19. We determined the expression levels of receptor ACE2 and CD147, and serine protease TMPRSS2 in human and mouse brain cell lines and mouse different region of brain tissues with qRT-PCR and Western blot. The results showed that the expression pattern of all them was very different to that of lung. ACE2 is lower but CD147 is higher expressed in mostly brain cell lines and mouse brain tissues comparing with lung cell line and tissue, and TMPRSS2 has consistent expression in brain cell lines and mouse lung tissues. It is suggested that SARS-CoV-2 might have a different way of infection to cerebral nervous system. Our finding will offer the clues to predict the possibility of SARS-CoV-2 infection to human brain nervous system and pathogenicity.

(-)-Epigallocatechin-3-gallate (EGCG) is the most abundant catechin in green tea. In this study, we found that hepatitis C virus (HCV) infection was significantly suppressed by EGCG in an HCV cell culture (HCVcc) system using a JFH1-GFP chimeric virus, with a 50 % effective concentration (EC(50)) of 17.9 μM. The inhibitory activity of EGCG was confirmed by monitoring HCV RNA and protein expression levels in Huh7.5.1 cells infected with the JFH1 virus. Moreover, we demonstrated that the inhibitory mechanisms of EGCG were attributable to the suppression of both the HCV entry and RNA replication steps, although EGCG had little effect on translation directed by the viral internal ribosome entry site (IRES). Furthermore, HCV could be rapidly eliminated from cell cultures after two and five passages in the presence of 50 and 25 μM EGCG, respectively. These results indicate that EGCG is a potential candidate as a preventive and antiviral drug for HCV infection.

Vpr, an accessory gene product of HIV-1, has been reported in the plasma of HIV-1-positive patients, and exogenous Vpr induces the reactivation of viral production from latently infected cells and the apoptosis of T cells in vitro. These observations imply that Vpr is important in AIDS development, but the clinical relevance of the findings cannot be evaluated fully because the actual plasma Vpr concentration in HIV-1-positive patients is unknown. Here we generated two monoclonal antibodies against different portions of Vpr and successfully identified Vpr as a 14-kDa protein in HIV-1-positive patients. Semiquantitative analysis using a recombinant Vpr revealed that the concentration of Vpr in patient plasma was approximately 0.7 nM (10 ng/ml). Cross-sectional analysis of 52 HIV-1-positive patients revealed that the presence of Vpr detected in 20 patients was positively correlated with HIV-1 RNA copy number (p > 0.03), but not with the number of CD4(+) T cells. This is the first report demonstrating the actual amount of Vpr in HIV-1-positive patients, and the possible linkage of Vpr and viral titers indicates that it is important to continue to carry out the sequential analysis of Vpr, especially in clinical courses of HIV-1-positive patients. The threshold of viral titers, where Vpr appears in the patients' plasma, if present, contributes to better understanding the role of Vpr in AIDS pathogenesis.

The review intends to present and recapitulate the current knowledge on the roles and importance of regulatory RNAs, such as microRNAs and small interfering RNAs, RNA binding proteins and enzymes processing RNAs or activated by RNAs, in cells infected by RNA viruses. The review focuses on how non-coding RNAs are involved in RNA virus replication, pathogenesis and host response, especially in retroviruses HIV, with examples of the mechanisms of action, transcriptional regulation, and promotion of increased stability of their targets or their degradation.