Functional genomics screens reveal a role for TBC1D24 and SV2B in antibody-dependent enhancement of dengue virus infection.

Dengue virus (DENV) can hijack non-neutralizing IgG antibodies to facilitate its uptake into target cells expressing Fc gamma receptors (FcgR) - a process known as antibody-dependent enhancement (ADE) of infection. Beyond a requirement for FcgR, host dependency factors for this non-canonical infection route remain unknown. To identify cellular factors exclusively required for ADE, here, we performed CRISPR knockout screens in an system permissive to infection only in the presence of IgG antibodies.

Broad-spectrum activity of bulevirtide against clinical isolates of HDV and recombinant pan-genotypic combinations of HBV/HDV.

Background & Aims: Bulevirtide (BLV) is a small lipopeptide agent that specifically binds to the sodium taurocholate cotransporting polypeptide (NTCP) bile salt transporter and HBV/HDV receptor on the surface of human hepatocytes and inhibits HDV and HBV entry. As a satellite virus of HBV, HDV virions are formed after assembly of HDV RNA with the HBV envelope proteins (HBsAg). Because both viruses exist as eight different genotypes, this creates a potential for high diversity in the HBV/HDV combinations.

Identification of the Cell-Surface Protease ADAM9 as an Entry Factor for Encephalomyocarditis Virus.

Encephalomyocarditis virus (EMCV) is an animal pathogen and an important model organism, whose receptor requirements are poorly understood. Here, we employed a genome-wide haploid genetic screen to identify novel EMCV host factors. In addition to the previously described picornavirus receptors sialic acid and glycosaminoglycans, this screen unveiled important new host factors for EMCV.

An RNA-centric dissection of host complexes controlling flavivirus infection.

Flaviviruses, including dengue virus (DENV) and Zika virus (ZIKV), cause severe human disease. Co-opting cellular factors for viral translation and viral genome replication at the endoplasmic reticulum is a shared replication strategy, despite different clinical outcomes. Although the protein products of these viruses have been studied in depth, how the RNA genomes operate inside human cells is poorly understood.

Editing N-Glycan Site Occupancy with Small-Molecule Oligosaccharyltransferase Inhibitors.

The oligosaccharyltransferase (OST) is a multisubunit enzyme complex that N-glycosylates proteins in the secretory pathway and is considered to be constitutive and unregulated. However, small-molecule OST inhibitors such as NGI-1 provide a pharmacological approach for regulating N-linked glycosylation. Herein we design cell models with knockout of each OST catalytic subunit (STT3A or STT3B) to screen the activity of NGI-1 and its analogs.

A Small-Molecule Oligosaccharyltransferase Inhibitor with Pan-flaviviral Activity.

The mosquito-borne flaviviruses include important human pathogens such as dengue, Zika, West Nile, and yellow fever viruses, which pose a serious threat for global health. Recent genetic screens identified endoplasmic reticulum (ER)-membrane multiprotein complexes, including the oligosaccharyltransferase (OST) complex, as critical flavivirus host factors. Here, we show that a chemical modulator of the OST complex termed NGI-1 has promising antiviral activity against flavivirus infections.

Antigen presentation profiling reveals recognition of lymphoma immunoglobulin neoantigens.

Cancer somatic mutations can generate neoantigens that distinguish malignant from normal cells. However, the personalized identification and validation of neoantigens remains a major challenge. Here we discover neoantigens in human mantle-cell lymphomas by using an integrated genomic and proteomic strategy that interrogates tumour antigen peptides presented by major histocompatibility complex (MHC) class I and class II molecules.

Chromatin-Remodeling Complex SWI/SNF Controls Multidrug Resistance by Transcriptionally Regulating the Drug Efflux Pump ABCB1.

Anthracyclines are among the most effective yet most toxic drugs used in the oncology clinic. The nucleosome-remodeling SWI/SNF complex, a potent tumor suppressor, is thought to promote sensitivity to anthracyclines by recruiting topoisomerase IIa (TOP2A) to DNA and increasing double-strand breaks. In this study, we discovered a novel mechanism through which SWI/SNF influences resistance to the widely used anthracycline doxorubicin based on the use of a forward genetic screen in haploid human cells, followed by a rigorous single and double-mutant epistasis analysis using CRISPR/Cas9-mediated engineering.

Genetic dissection of Flaviviridae host factors through genome-scale CRISPR screens.

The Flaviviridae are a family of viruses that cause severe human diseases. For example, dengue virus (DENV) is a rapidly emerging pathogen causing an estimated 100 million symptomatic infections annually worldwide. No approved antivirals are available to date and clinical trials with a tetravalent dengue vaccine showed disappointingly low protection rates.

The adherens junctions control susceptibility to Staphylococcus aureus α-toxin.

Staphylococcus aureus is both a transient skin colonizer and a formidable human pathogen, ranking among the leading causes of skin and soft tissue infections as well as severe pneumonia. The secreted bacterial α-toxin is essential for S. aureus virulence in these epithelial diseases.

Gene essentiality and synthetic lethality in haploid human cells.

Although the genes essential for life have been identified in less complex model organisms, their elucidation in human cells has been hindered by technical barriers. We used extensive mutagenesis in haploid human cells to identify approximately 2000 genes required for optimal fitness under culture conditions. To study the principles of genetic interactions in human cells, we created a synthetic lethality network focused on the secretory pathway based exclusively on mutations.

Development and Characterization of Broadly Cross-reactive Monoclonal Antibodies Against All Known Ebolavirus Species.

As of 25 March 2015, the largest recorded outbreak of Ebola virus infection is ongoing, with almost 25 000 cases and >10 000 deaths. There are 5 genetically and antigenically distinct species within the genus Ebolavirus. Limited cross-reactivity and protection is observed between these 5 Ebolavirus species, which complicates vaccine development.

Kinetic pathway of 40S ribosomal subunit recruitment to hepatitis C virus internal ribosome entry site.

Translation initiation can occur by multiple pathways. To delineate these pathways by single-molecule methods, fluorescently labeled ribosomal subunits are required. Here, we labeled human 40S ribosomal subunits with a fluorescent SNAP-tag at ribosomal protein eS25 (RPS25).

Human induced pluripotent stem cell-derived cardiomyocytes as an in vitro model for coxsackievirus B3-induced myocarditis and antiviral drug screening platform.

Rationale: Viral myocarditis is a life-threatening illness that may lead to heart failure or cardiac arrhythmias. A major causative agent for viral myocarditis is the B3 strain of coxsackievirus, a positive-sense RNA enterovirus. However, human cardiac tissues are difficult to procure in sufficient enough quantities for studying the mechanisms of cardiac-specific viral infection.

Differential virus host-ranges of the Fuselloviridae of hyperthermophilic Archaea: implications for evolution in extreme environments.

An emerging model for investigating virus-host interactions in hyperthermophilic Archaea is the Fusellovirus-Sulfolobus system. The host, Sulfolobus, is a hyperthermophilic acidophile endemic to sulfuric hot springs worldwide. The Fuselloviruses, also known as Sulfolobus Spindle-shaped Viruses (SSVs), are "lemon" or "spindle"-shaped double-stranded DNA viruses, which are also found worldwide.