Benzothiazepinecarboxamides: Novel hepatitis C virus inhibitors that interfere with viral entry and the generation of infectious virions

Comparative analysis of whole-transcriptome RNA expression of lung tissue of Chinese soft-shell turtle infected by Trionyx sinensis Hemorrhagic Syndrome Virus

Trionyx sinensis Hemorrhagic Syndrome Virus (TSHSV), the first aquatic arterivirus identified in China, causes severe mortality to T. sinensis. In this study, we sought to determine the functions of T. sinensis mRNAs and non-coding RNAs (ncRNAs) that were differentially expressed (DE) over different periods of TSHSV infection of T. sinensis lung. We used RT-qPCR to validate the sequencing results of select RNAs, confirming their reliable and referable nature. Gene Ontology (GO) annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis were used to predict multiple biological functions and signaling pathways in various comparison groups (1-day versus mock, 3-day versus 1-day, and 5-day versus 3-day). Multiple types of differentially expressed RNA, including mRNA, lncRNA, circRNA, and miRNA, were associated with cardiac dysfunction, coagulation abnormalities, and arachidonic acid metabolism at day 1. Pre-inflammatory cytokines and inflammatory factors such as PLA2G4A, cPLA2, γ-GGT1, TNFRSF14, TCP11L2, PTER CYP2J2 and LTC4S, were noticeably regulated at the same time. On day 3, multiple GO terms and KEGG pathways were implicated, including those related to virus defense, apoptosis, pyroptosis, and inflammatory response. Notably, key genes such as RSAD2, TRIM39, STAT4, CASP1, CASP14, MYD88, CXCL3, CARD11, ZBP1, and ROBO4 exhibited significant regulation. The lncRNAs and circRNAs that targeted the genes involved in viral recognition (TLR5), apoptosis (CARD11), pyroptosis (ZBP1), inflammatory processes (NEK7, RASGRP4, and SELE) and angiogenesis (ROBO4) exhibited significant regulation. Significantly regulated miRNAs were primarily linked to genes involved in apoptosis (Let-7f-3p, miR-1260a, miR-455-3p), and inflammation (miR-146a, miR-125a, miR-17a, miR-301b, and miR-30a-3p). The findings could advance our understanding of the host immunological response to TSHSV and offer new ideas for developing effective strategies to prevent infection of T. sinensis.

SARS-CoV-2 RNA-dependent RNA polymerase as a therapeutic target for COVID-19

Introduction: The current SARS-CoV-2 pandemic urgently demands for both prevention and treatment strategies. RNA-dependent RNA-polymerase (RdRp), which has no counterpart in human cells, is an excellent target for drug development. Given the time-consuming process of drug development, repurposing drugs approved for other indications or at least successfully tested in terms of safety and tolerability, is an attractive strategy to rapidly provide an effective medication for severe COVID-19 cases.Areas covered: The currently available data and upcominSg studies on RdRp which can be repurposed to halt SARS-CoV-2 replication, are reviewed.Expert opinion: Drug repurposing and design of novel compounds are proceeding in parallel to provide a quick response and new specific drugs, respectively. Notably, the proofreading SARS-CoV-2 exonuclease activity could limit the potential for drugs designed as immediate chain terminators and favor the development of compounds acting through delayed termination. While vaccination is awaited to curb the SARS-CoV-2 epidemic, even partially effective drugs from repurposing strategies can be of help to treat severe cases of disease. Considering the high conservation of RdRp among coronaviruses, an improved knowledge of its activity in vitro can provide useful information for drug development or drug repurposing to combat SARS-CoV-2 as well as future pandemics.

Common Nodes of Virus-Host Interaction Revealed Through an Integrated Network Analysis

Viruses are one of the major causes of acute and chronic infectious diseases and thus a major contributor to the global burden of disease. Several studies have shown how viruses have evolved to hijack basic cellular pathways and evade innate immune response by modulating key host factors and signaling pathways. A collective view of these multiple studies could advance our understanding of virus-host interactions and provide new therapeutic perspectives for the treatment of viral diseases. Here, we performed an integrative meta-analysis to elucidate the 17 different host-virus interactomes. Network and bioinformatics analyses showed how viruses with small genomes efficiently achieve the maximal effect by targeting multifunctional and highly connected host proteins with a high occurrence of disordered regions. We also identified the core cellular process subnetworks that are targeted by all the viruses. Integration with functional RNA interference (RNAi) datasets showed that a large proportion of the targets are required for viral replication. Furthermore, we performed an interactome-informed drug re-purposing screen and identified novel activities for broad-spectrum antiviral agents against hepatitis C virus and human metapneumovirus. Altogether, these orthogonal datasets could serve as a platform for hypothesis generation and follow-up studies to broaden our understanding of the viral evasion landscape.

Micrococcin P1, a naturally occurring macrocyclic peptide inhibiting hepatitis C virus entry in a pan-genotypic manner

Hepatitis C virus (HCV) is considered a major public health concern worldwide. Despite recent advances in curing chronic hepatitis C, unmet medical needs still remain, especially due to the high economic burden of therapies. Accordingly, our study aimed to identify affordable novel HCV inhibitors by screening of natural product compound libraries. We identified micrococcin P1, a macrocyclic peptide antibiotic, inhibiting HCV entry in a pan-genotypic manner with an EC50 range of 0.1-0.5 μM. Micrococcin P1 interfered with HCV entry at an attachment step. Furthermore, micrococcin P1 efficiently inhibited HCV spread by blocking cell-free infection as well as cell-to-cell transmission, without affecting the secretion of infectious virions. Interestingly, the putative molecular target of micrococcin P1 is glycoprotein E2 (IIe-630-Thr), as revealed by selection for viral drug resistance. In addition, micrococcin P1 inhibited sofosbuvir-resistant HCV strains and showed synergy in combination with selected HCV drugs, suggesting an alternative treatment paradigm for patients. In conclusion, we identified micrococcin P1 as specifically inhibiting entry of all HCV genotypes and demonstrated that micrococcin P1 potentially could add value to therapies in combination with current HCV interventions.