SARS-CoV-2 encoded microRNAs are involved in the process of virus infection and host immune response

The outbreak of COVID-19 caused by SARS-CoV-2 is spreading worldwide,with the pathogenesis mostly unclear.Both virus and host-derived microRNA(miRNA)play essential roles in the pathology of virus infection.This study aims to uncover the mechanism for SARS-CoV-2 pathogenicity from the perspective of miRNA.We scanned the SARS-CoV-2 genome for putative miRNA genes and miRNA targets and conducted in vivo experiments to validate the virus-encoded miRNAs and their regulatory role on the putative targets.One of such virus-encoded miRNAs,MR147-3p,was overexpressed that resulted in significantly decreased transcript levels of all of the predicted targets in human,i.e.,EXOC7,RAD9A,and TFE3 in the virus-infected cells.The analysis showed that the immune response and cytoskeleton organization are two of the most notable biological processes regulated by the infection-modulated miRNAs.Additionally,the genomic mutation of SARS-CoV-2 contributed to the changed miRNA repository and targets,suggesting a possible role of miRNAs in the attenuated phenotype of SARS-CoV-2 during its evolution.This study provided a comprehensive view of the miRNA-involved regulatory system during SARS-CoV-2 infection,indicating possible antiviral therapeutics against SARS-CoV-2 through intervening miRNA regulation.

Pleiotropic Effect of tatC Mutation on Metabolism of Pathogen Yersinia enterocolitica

Objective To analyze the impact of depletion of the twin arginine translocation （TAT） system on virulence and physiology of Yersinia enterocolitica for a better understanding of its pathogenicity. Methods We constructed a △tatC：：Sp^R mutant of Yersinia enterocolitica by P1 phage mediated transduction using Escherichia coli K-12 △tatC：：Sp^R strain as a donor. Results A Pl-mediated genetic material transfer was found between the two species of enterobacteria, indicating a great potential of acquisition of antibiotic resistance in emergency of a new threatening pathogen by genetic material exchanges. Periplasmic trimethylamine N-oxidase reductase activity was detected in the wild type E enterocolitica strain and translocation of this enzyme was completely abolished by the △tatC：：Sp^R mutation. In addition, the △tatC：：Sp^R mutation showed a pleiotropic effect on the metabolism of E enterocolitica. However, the tat mutation did not seem to affect the mobility and virulence of Y. enterocolitica under the conditions used. Conclusion Unlike other pathogenic bacteria studied, the TAT system of E enterocolitica might play an important role in the pathogenic process, which is distinct from other pathogens, such as Pseudomonas aeruginosa and enterohemorrhagic E. coli O 157：H7.

An integrative drug repositioning framework discovered a potential therapeutic agent targeting COVID-19

The global spread of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)requires an urgent need to find effective therapeutics for the treatment of coronavirus disease 2019(COVID-19).In this study,we developed an integrative drug repositioning framework,which fully takes advantage of machine learning and statistical analysis approaches to systematically integrate and mine large-scale knowledge graph,literature and transcriptome data to discover the potential drug candidates against SARS-CoV-2.Our in silico screening followed by wet-lab validation indicated that a poly-ADP-ribose polymerase 1(PARP1)inhibitor,CVL218,currently in Phase I clinical trial,may be repurposed to treat COVID-19.Our in vitro assays revealed that CVL218 can exhibit effective inhibitory activity against SARS-CoV-2 replication without obvious cytopathic effect.In addition,we showed that CVL218 can interact with the nucleocapsid(N)protein of SARS-CoV-2 and is able to suppress the LPS-induced production of several inflammatory cytokines that are highly relevant to the prevention of immunopathology induced by SARS-CoV-2 infection.