Current research in virological science最新文献

Human rhinoviruses are known to cause mild upper respiratory tract infections. They are also now known to cause severe laryngotracheitis and play an important role in triggering asthma attacks. An anti-viral drug against rhinoviruses viruses would be helpful. Acetylsalicylic acid (ASA) might be such a candidate with proven activity against several RNA viruses in vitro and in vivo. ASA was initially mentioned as an anti-inflammatory compound. Viral infections are often accompanied by inflammatory processes. In this study, the anti-viral and anti-inflammatory activities of ASA were examined using the HeLa rhinovirus-infection model. Human rhinovirus (HRV14, major group) infection was quantified by flow cytometry using a monoclonal antibody against the major capsid protein HRV-VP3 in combination with analysis of surface expression of CD54, a key molecule involved in the initiation of an immune response. Our in vitro studies demonstrate on a single cell level HRV14 infection-dependent intra-cellular expression of the HRV-VP3 protein. This expression correlated with HRV14 infection severity and could be dose-dependently blocked with ASA. Further, infection-dependent VP3 expression correlated with a down-regulation of surface antigen expression of CD54. This CD54 down-regulation could also be dose-dependently blocked by ASA supporting the anti-viral efficacy of ASA.

Endemic human coronaviruses (hCoVs) 229E and OC43 cause respiratory disease with recurrent infections, while severe acute respiratory syndrome (SARS)-CoV-2 spreads across the world with impact on health and societies. Here, we report an image-based multicycle infection procedure with α-coronavirus hCoV-229E-eGFP in an arrayed chemical library screen of 5440 clinical and preclinical compounds. Toxicity counter selection and challenge with the β-coronaviruses OC43 and SARS-CoV-2 in tissue culture and human airway epithelial explant cultures (HAEEC) identified four FDA-approved compounds with oral availability. Methylene blue (MB, used for the treatment of methemoglobinemia), Mycophenolic acid (MPA, used in organ transplantation) and the anti-fungal agent Posaconazole (POS) had the broadest anti-CoV spectrum. They inhibited the shedding of SARS-CoV-2 and variants-of-concern (alpha, beta, gamma, delta) from HAEEC in either pre- or post exposure regimens at clinically relevant concentrations. Co-treatment of cultured cells with MB and the FDA-approved SARS-CoV-2 RNA-polymerase inhibitor Remdesivir reduced the effective anti-viral concentrations of MB by 2-fold, and Remdesivir by 4 to 10-fold, indicated by BLISS independence synergy modelling. Neither MB, nor MPA, nor POS affected the cell delivery of SARS-CoV-2 or OC43 (+)sense RNA, but blocked subsequent viral RNA accumulation in cells. Unlike Remdesivir, MB, MPA or POS did not reduce the release of viral RNA in post exposure regimen, thus indicating infection inhibition at a post-replicating step as well. In summary, the data emphasize the power of unbiased, full cycle compound screens to identify and repurpose broadly acting drugs against coronaviruses.

Recombinant herpes simplex virus strains can be constructed by several methods, including homologous recombination, bacterial artificial chromosome manipulation, and yeast genetic methods. Homologous recombination may have the advantage of introducing fewer genetic alterations in the viral genome, but the low level of recombinants can make this method more time consuming if there is no screen or selection. In this study we used complementing cell lines that express Cas9 and guide RNAs targeting the parental virus to rapidly generate recombinant viruses. Analysis of the progeny viruses indicated that CRISPR-Cas9 both promoted recombination to increase recombinant viruses and selected against parental viruses in the transfection progeny viruses. This approach can also be used to enrich for recombinants made by any of the current methods.

Infection with pathogenic viruses is often sensed by innate receptors such as Toll-Like Receptors (TLRs) which stimulate type I and III interferons (IFNs) responses, to generate an antiviral state within many cell types. To counteract these antiviral systems, many viruses, including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), encode non-structural proteins (NSPs) that mediate immune evasion. Using an overexpression system in A549 ​cells, we demonstrated a significant increase (p ​≤ ​0.0001) in Vesicular Stomatitis Virus (VSV)-EGFP reporter virus replication in cell lines overexpressing either the SARS-CoV-2 NSP1 or NSP15 when compared to control A549 ​cells. The increase in VSV-EGFP virus output was associated with a decrease in TLR2, TLR4 and TLR9 protein expression and a lack of antiviral protein production. Truncation of both NSP1 and NSP15 led to an increase in cellular TLR2, TLR4 and TLR9 as well as a decrease in TLR2 expression respectively. This observation can be attributed to the presence of a functional domain in NSP1 and NSP15 between amino acid (aa) 120–180 and aa 230–346, respectively. Both TLR3 and TLR9 ligands but not TLR2 ligand were highly effective at overcoming NSP1 and NSP15 functional interference based on significant decrease (p ​≤ ​0.0001) in VSV-EGFP virus replication. NSP1 or NSP15 intracellular interactions are likely low affinity interactions that can be easily disrupted by stimulating cells with specific TLR3 and TLR9 ligands. This report provides insights into the role of SARS-CoV-2 NSP1 and NSP15 in limiting specific TLR pathway activation, as an evasive mechanism against host innate responses.

Grapevine fruits produced in China are often infected by grapevine berry inner necrosis virus (GINV). GINV disease is the most economically important viral disease of the grapevine, characterized by discoloration on the fruit surface and necrosis of the flesh. In this study, the transcriptome sequencing technology revealed 1700 differently expressed genes (DEGs), with 846 up-regulated and 854 down-regulated genes in Crimson seedless grapevine during the GINV infection. Both Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were conducted to classify the DEGs. The top 10 GO terms were enriched in GINV versus mock, and these enriched GO terms were mainly classified into three categories, namely, 324 cellular components, 2062 biological processes, and 940 molecular functions. Based on the P-values, the KEGG pathway analysis indicated that 96 major pathways were identified in GINV versus mock, and 20 major enrichment pathways were significantly enriched. Using quantitative real-time polymerase chain reaction (qRT-PCR), we validated the differential expression of 12 genes. The expression patterns of 11 genes were consistent with the RNA-sequencing (RNA-seq) results, except for one gene. Thus, our study provides comprehensive transcriptome information on the GINV–grapevine interaction, thereby improving our understanding of virus–host interactions.

Most viral pathogens causing epidemics and pandemics are zoonotic, emerging from wildlife reservoirs like SARS CoV2 causing the global Covid-19 pandemic, although animal origin of this virus remains a mystery. Cross-species transmission of pathogens from animals to humans is known as zoonosis. However, pathogens are also transmitted from humans to animals in regions where there is a close interaction between animals and humans by ‘reverse transmission’ (anthroponosis).

Molecular evidence for the transmission of two zoonotic RNA viruses at the human-monkey interface in Rajasthan forests is presented here: a) the apathogenic Simian Foamy Viruses (SFV), and b): Influenza A viruses (IAV)-like virus, etiologic agent for human flu infecting wild Indian rhesus monkeys inhabiting Rajasthan forests.

The data provide critical information on ecology and evolution of viruses of Public Health relevance. During replication, viral genomes mutate along the transmission route to adapt to the new hosts, generating new variants that are likely to have properties different from the founder viruses.

Wild Indian monkeys are under-sampled for monitoring infectious diseases mainly because of the difficulties with sample collection. Monkeys are perceived as religious icons by the Hindus in India. It is extremely difficult to obtain permission from the Forest and Wildlife Department government authorities to collect wild simian blood samples for surveillance of infectious diseases caused by viral pathogens.

Reducing animal-human contact and affordable vaccination are two relevant anti-viral strategies to counteract the spread of infectious zoonotic pathogens.

Genbank Accession numbers: Indian SFVmac: ADN94420, IAV like virus: MZ298601.

Interferons (IFNs) are soluble glycoproteins secreted by infected and transformed cells. Since their discovery in 1957 as a factor that “interferes” with viral replication, IFNs have been shown to protect against a wide range of infections and malignancies. The antiviral and anticancer properties of IFNs are largely attributed to their ability to alert the host immune system to kill infected and cancer cells. In this review, we will discuss the functions of a specific subgroup of ubiquitous IFNs, type I IFNs (IFN-Is), in viral infections and cancers. Although IFN-Is alleviate cancers and viral infections, the molecular mechanisms underlying their therapeutic potential remain to be fully delineated. To harness the full therapeutic potential of IFN-Is, its mediators, and its effectors as safe antiviral and anticancer agents, here, we describe what is known about these cytokines and identify the underexplored potential applications of IFN-Is at the interface of viral infections and cancers. We predict that strategies which restore IFN-I-driven antiviral and anticancer immune surveillance would be particularly attractive early therapeutic interventions to block virus-induced tumorigenesis and safeguard patients with cancer from contracting deadly viral infections.

Viral Hemorrhagic Fever (VHF) is a group of acute zoonotic diseases with high mortality rates caused by seven different families of viruses that infect both humans and animals. VHF is characterized by hemorrhagic manifestations and lethal platelet dysfunction, if not treated properly. Most of the VHF is transmitted to humans by different types of vectors like rodents, bats, ticks, voles, and mosquitoes. Some of the common and deadly VHF are associated with infections like Dengue, Ebola, Yellow Fever, and Hantavirus. These diseases are endemic in a certain part of the world and sometimes cause major outbreaks. Emerging and re-emerging VHF's remain a great health concern across the world due to poor prognosis and lack of specific vaccines or drugs for effective treatment. Understanding the disease pathogenesis of VHF could provide effective means for treating and monitoring the disease outcome. In this regard, the present review gives a brief overview of disease background, molecular pathogenesis of major VHF, and gaps in the understanding of disease mechanism and current trends in disease management.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is responsible for the current pandemic coronavirus disease of 2019 (COVID-19). Like other pathogens, SARS-CoV-2 infection can elicit production of the type I and III interferon (IFN) cytokines by the innate immune response. A rapid and robust type I and III IFN response can curb viral replication and improve clinical outcomes of SARS-CoV-2 infection. To effectively replicate in the host, SARS-CoV-2 has evolved mechanisms for evasion of this innate immune response, which could also modulate COVID-19 pathogenesis. In this review, we discuss studies that have reported the identification and characterization of SARS-CoV-2 proteins that inhibit type I IFNs. We focus especially on the mechanisms of nsp1 and ORF6, which are the two most potent and best studied SARS-CoV-2 type I IFN inhibitors. We also discuss naturally occurring mutations in these SARS-CoV-2 IFN antagonists and the impact of these mutations in vitro and on clinical presentation. As SARS-CoV-2 continues to spread and evolve, researchers will have the opportunity to study natural mutations in IFN antagonists and assess their role in disease. Additional studies that look more closely at previously identified antagonists and newly arising mutants may inform future therapeutic interventions for COVID-19.