Replication competent HIV-guided CRISPR screen identifies antiviral factors including targets of the accessory protein Nef

Single-cell analyses identify monocyte gene expression profiles that influence HIV-1 reservoir size in acutely treated cohorts

Eliminating latent HIV-1 is a major goal of AIDS research but host factors determining the size of these reservoirs are poorly understood. Here, we investigate the role of host gene expression on HIV-1 reservoir size during suppressive antiretroviral therapy (ART). Peripheral blood cells of fourteen males initiating ART during acute infection and demonstrating effective viral suppression but varying magnitudes of total HIV-1 DNA were characterized by single-cell RNA sequencing. Differential expression analysis demonstrates increased CD14+ monocyte activity in participants having undetectable HIV-1 reservoirs, with IL1B expression inversely associating with reservoir size. This is validated in another cohort of 38 males comprised of different ancestry and HIV-1 subtypes, and with intact proviral DNA assay (IPDA®) measurements. Modeling interactions show monocyte IL1B expression associates inversely with reservoir size at higher frequencies of central memory CD4+ T cells, linking monocyte IL1B expression to cell types known to be reservoirs for persistent HIV-1. Functional analyses reveal that IL1B activates NF-κB, thereby promoting productive HIV-1 infection while simultaneously suppressing viral spread, suggesting a natural latency reversing activity to deplete the reservoir in ART-treated individuals. Altogether, scRNA-seq analyses reveal that monocyte IL1B expression could decrease HIV-1 proviral reservoirs in individuals initiating ART during acute infection.

Deep mutational scanning and CRISPR-engineered viruses: tools for evolutionary and functional genomics studies

Recent advancements in synthetic biology and sequencing technologies have revolutionized the ability to manipulate viral genomes with unparalleled precision. This review focuses on two powerful methodologies: deep mutational scanning and CRISPR-based genome editing, that enable comprehensive mutagenesis and detailed functional characterization of viral proteins. These approaches have significantly deepened our understanding of the molecular determinants driving viral evolution and adaptation. Furthermore, we discuss how these advances provide transformative insights for future vaccine development and therapeutic strategies.

Regulation of viral replication by host restriction factors

Viral infectious diseases, caused by numerous viruses including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), influenza A virus (IAV), enterovirus (EV), human immunodeficiency virus (HIV), hepatitis B virus (HBV), and human papillomavirus (HPV), pose a continuous threat to global health. As obligate parasites, viruses rely on host cells to replicate, and host cells have developed numerous defense mechanisms to counteract viral infection. Host restriction factors (HRFs) are critical components of the early antiviral response. These cellular proteins inhibit viral replication and spread by impeding essential steps in the viral life cycle, such as viral entry, genome transcription and replication, protein translation, viral particle assembly, and release. This review summarizes the current understanding of how host restriction factors inhibit viral replication, with a primary focus on their diverse antiviral mechanisms against a range of viruses, including SARS-CoV-2, influenza A virus, enteroviruses, human immunodeficiency virus, hepatitis B virus, and human papillomavirus. In addition, we highlight the crucial role of these factors in shaping the host-virus interactions and discuss their potential as targets for antiviral drug development.

Dissecting host-microbe interactions with modern functional genomics

Interrogation of host-microbe interactions has long been a source of both basic discoveries and benefits to human health. Here, we review the role that functional genomics approaches have played in such efforts, with an emphasis on recent examples that have harnessed technological advances to provide mechanistic insight at increased scale and resolution. Finally, we discuss how concurrent innovations in model systems and genetic tools have afforded opportunities to interrogate additional types of host-microbe relationships, such as those in the mammalian gut. Bringing these innovations together promises many exciting discoveries ahead.

Single-cell analyses reveal that monocyte gene expression profiles influence HIV-1 reservoir size in acutely treated cohorts

Elimination of latent HIV-1 is a major goal of AIDS research but the host factors determining the size of these reservoirs are poorly understood. Here, we investigated whether differences in host gene expression modulate the size of the HIV-1 reservoir during suppressive ART. Peripheral blood mononuclear cells (PBMC) from fourteen individuals initiating ART during acute infection who demonstrated effective viral suppression but varying magnitude of total HIV-1 DNA were characterized by single-cell RNA sequencing (scRNA-seq). Differentially expressed genes and enriched pathways demonstrated increased monocyte activity in participants with undetectable HIV-1 reservoirs. IL1B expression in CD14+ monocytes showed the greatest fold difference. The inverse association of IL1B with reservoir size was validated in an independent cohort comprised of 38 participants with different genetic backgrounds and HIV-1 subtype infections, and further confirmed with intact proviral DNA assay (IPDA®) measurements of intact HIV-1 proviruses in a subset of the samples. Modeling interactions with cell population frequencies showed that monocyte IL1B expression associated inversely with reservoir size in the context of higher frequencies of central memory CD4+ T cells, implicating an indirect effect of IL1B via the cell type well established to be a reservoir for persistent HIV-1. Signatures consisting of co-expressed genes including IL1B were highly enriched in the "TNFα signaling via NF-κB" geneset. Functional analyses in cell culture revealed that IL1B activates NF-κB, thereby promoting productive HIV-1 infection while simultaneously suppressing viral spread, suggesting a natural latency reversing activity to deplete the reservoir in ART treated individuals. Altogether, unbiased high throughput scRNA-seq analyses revealed that monocyte IL1B variation could decrease HIV-1 proviral reservoirs in individuals initiating ART during acute infection.

A review of virus host factor discovery using CRISPR screening

The emergence of genome-scale forward genetic screening techniques, such as Haploid Genetic screen and clustered regularly interspaced short palindromic repeats (CRISPR) knockout screen has opened new horizons in our understanding of virus infection biology. CRISPR screening has become a popular tool for the discovery of novel host factors for several viruses due to its specificity and efficiency in genome editing. Here, we review how CRISPR screening has revolutionized our understanding of virus-host interactions from scientific and technological viewpoints. A summary of the published screens conducted thus far to uncover virus host factors is presented, highlighting their experimental design and significant findings. We will outline relevant methods for customizing the CRISPR screening process to answer more specific hypotheses and compile a glossary of conducted CRISPR screens to show their design aspects. Furthermore, using flaviviruses and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) as examples, we hope to offer a broad-based perspective on the capabilities of CRISPR screening to serve as a reference point to guide future unbiased discovery of virus host factors.