Biology subjects

Hale, B. G.

Publications and source records attributed to Hale, B. G..

11 recordsLinked to original sources

bioRxiv2026

Developmental and molecular features shaping broad and synergistic actions of human autoantibodies targeting interferon-α

Neutralizing autoantibodies against interferon- (IFN) are associated with severe viral infections but may improve outcomes in IFN-driven autoimmunity. How these antibodies emerge, mature, and function at the molecular level remains unclear. Here, we tracked development of plasma neutralizing activity against all 12 IFNs in multiple human donors over years. Plasma neutralization frequently initiates with narrow IFN specificity, often IFN8, but increases in breadth and potency with individual kinetics. Monoclonal antibody analyses reveal that affinity maturation generates epitope-specific antibody classes, highlighting parallel emergence of subtype-restricted and broadly-reactive antibodies. Biophysical and structural characterization of human antibody-IFN complexes uncovers determinants of initial specificity and breadth development. Strikingly, antibodies engaging non-competing, neutralizing epitopes can act co-operatively to block IFN signaling, and some combinations trigger Fc-effector functions via cell surface IFN:IFNAR2 interactions that may eliminate IFN-responsive cells. Our findings reveal features shaping anti-IFN autoantibody repertoires and unappreciated synergistic mechanisms that amplify their potency and pathogenic potential.

immunology↗

bioRxiv2026

Influenza A virus NS1 sequesters RNA:DNA hybrids to evade RNase H1-dependent innate immunity

RNA:DNA hybrids, and their aberrant accumulation, are key regulators of human genome integrity and innate immunity. Given the functional parallels and extensive interplay between the human genome and viral genetic material, RNA:DNA hybrids also have established roles during infections with DNA viruses and retroviruses. Nevertheless, the presence and consequences of RNA:DNA hybrids in RNA virus infections, which lack a DNA phase, remain largely uncharacterized. Here, we show that infection of human cells with influenza A virus (IAV), but not several other respiratory negative-sense RNA viruses, induces the unexpected accumulation of RNA:DNA hybrids in perinuclear regions. Sequencing of infection-induced cytoplasmic RNA:DNA hybrids revealed that they derive predominantly from the human host genome, with apparent preference for intronic and intergenic sequences, although an intriguing fraction also originates from the IAV genome, with some enrichment for specific viral segments. Notably, we identify the IAV non-structural protein, NS1, as a key determinant of RNA:DNA hybrid localization and stability: NS1 is required for, and co-localizes with, perinuclear RNA:DNA hybrids, and its absence appears to sensitize RNA:DNA hybrids to metabolism by the cellular ribonuclease, RNase H1. Furthermore, experimental loss of RNase H1 attenuates IAV-induced antiviral responses, including type I interferon and inflammatory gene expression programs, indicating that RNA:DNA hybrid metabolism likely contributes to host defense. Overall, our findings uncover host- and viral-origin RNA:DNA hybrids as a previously unrecognized feature of a human pathogenic RNA virus infection, and suggest a mechanism by which a viral product antagonizes host responses mediated via these unusual nucleic acids by spatial sequestration.

immunology↗

bioRxiv2026

Human antibodies against West Nile and related orthoflaviviruses

West Nile virus (WNV) is a mosquito-borne pathogen of global concern that can cause fatal neuroinvasive disease. No specific prophylaxis or treatment exists for WNV or related orthoflavivirus infections, and the determinants of human disease severity remain poorly understood. Here, we report that neutralizing autoantibodies against type I interferons do not impair antiviral antibody development. Among the fully human monoclonal antibodies with potent neutralizing activity against WNV that were discovered, W010 targets a unique epitope within the envelope protein domain III (EDIII) and confers both pre- and post-exposure protection in a murine WNV model, even when interferon signaling is impaired. A second protective antibody, W014, exhibits broad cross-neutralization of other pathogenic orthoflavivirus members, including Japanese encephalitis virus, Murray Valley encephalitis virus, Saint Louis encephalitis virus, and Usutu virus. These findings identify key neutralizing epitopes on WNV EDIII and provide candidates for the development of antibody-based interventions against encephalitic orthoflavivirus infections.

immunology↗

bioRxiv2025

TRIM28 is a target for paramyxovirus V proteins

SUMO-modified Tripartite Motif Protein 28 (TRIM28; KAP1) plays a crucial role in repressing endogenous retroelement (ERE) transcription. We previously provided evidence that loss of SUMO-modified TRIM28 triggered by influenza A virus (IAV) infection promotes activation of host antiviral immunity via a mechanism involving derepression of EREs and production of immunostimulatory RNAs. While the IAV NS1 protein might limit consequences of such activation via its dsRNA-binding activity, we hypothesized that other human pathogenic viruses could have evolved more direct strategies to counteract this potential ERE-based defense system. Here, we reveal that V proteins from diverse paramyxoviruses, including Measles, Mumps, Parainfluenza, and Nipah/Hendra viruses, can all engage with TRIM28. Notably, the efficiency of engagement varies markedly between virus species, a phenotype that can be linked to specific residues within the C-terminal domain of V proteins. Further mapping showed that V proteins target both the TRIM28 Coiled-Coil domain and the TRIM28 PHD-Bromodomain, which contains the functionally-relevant TRIM28 SUMO-modification sites necessary for ERE repression. In this context, while paramyxovirus infection triggers canonical stress-associated phosphorylation of TRIM28, loss of SUMO-modified TRIM28 does not occur, and minimal induction of the TRIM28-dependent ERE RNA, HERVK14C, is observed. Furthermore, pre-infection with Parainfluenza virus type 2, which encodes a V protein that efficiently engages with TRIM28, limits subsequent IAV-triggered loss of SUMO-modified TRIM28 and upregulation of HERVK14C RNA. These findings dissect the interplay between paramyxoviruses and TRIM28, providing support for the concept of a TRIM28-regulated ERE-based antiviral defense system by uncovering a potential viral antagonistic measure. ImportanceHost recognition of viral nucleic acids is fundamental for stimulating antiviral immunity. To prevent aberrant immune activation, cells must precisely differentiate "non-self" from "self" nucleic acids. Endogenous retroelements (EREs), despite their self-origin, can produce immunostimulatory RNAs that blur this distinction, and may have been functionally co-opted to enhance antiviral immunity in response to some infections. Normally, ERE transcription is repressed by the host protein TRIM28, the function of which is dynamically modulated by SUMO-modification. Here, we demonstrate that paramyxoviruses engage TRIM28, maintaining it in its repressive, SUMO-modified form during infection. We propose that this virus-host interaction limits ERE activation and consequently suppresses ERE-driven immune signaling, revealing a previously unidentified mechanism of immune evasion by paramyxoviruses.

microbiology↗

bioRxiv2024

An Atlas of Protein Phosphorylation Dynamics During Interferon Signaling

Interferons (IFNs, types I-III) have pleiotropic functions in promoting antiviral and anti-tumor responses, as well as in modulating inflammation. Dissecting the signaling mechanisms elicited by different IFNs is therefore critical to understand their phenotypes. Here, we use mass spectrometry to investigate the early temporal dynamics of cellular protein phosphorylation in response to stimulation with IFN2, IFN{beta}, IFN{omega}, IFN{gamma}, and IFN{lambda}1, representing all IFN types. We report an atlas of over 700 common or unique phosphorylation events reprogrammed by these IFNs, revealing both previously known and uncharacterized modifications. Functional screening and mechanistic studies identify that several factors differentially-modified in response to IFNs contribute to host antiviral responses, either directly or by supporting IFN-stimulated gene or protein production. Among these, phosphorylation of PLEKHG3 at serine-1081 creates a phospho-regulated binding motif for the docking of 14-3-3 proteins, and together these factors contribute to coordinating efficient IFN-stimulated gene expression independent of early JAK/STAT signaling. Our findings map the global phosphorylation landscapes regulated by IFN types I, II, and III, and provide a key resource to explore their functional consequences.

immunology↗

bioRxiv2024

Highly-sensitive reporter cell line for detection of interferon types I-III and their neutralization by antibodies

Interferons (IFNs) are a critical component of innate immune defenses and limit viral disease severity. To advance studies on IFNs and their neutralization by pathogenic autoantibodies, we generated a Renilla luciferase-based reporter cell line capable of detecting the activities of IFN-Is, IFN-II, and IFN-IIIs. The reporter cell line exhibits a 125-to 2000-fold higher sensitivity to IFNs than a commonly-used alternative biological reporter system, and allows for a rapid and simple live-cell workflow for detecting low titer amounts of neutralizing anti-IFN antibodies.

immunology↗

bioRxiv2024

Influenza A Virus NS1 Limits Recognition of Double-Stranded Transposable Elements by Cytosolic RNA Sensors

Influenza A virus (IAV) infection triggers de-repression of host transposable elements (TEs), which have the potential to form double-stranded (ds)RNAs and stimulate innate antiviral immunity. However, as wild-type IAV is generally a poor inducer of innate immunity, it remains unclear whether de-repressed TEs actually form dsRNAs recognizable by host cytosolic RNA sensors, or whether IAV might antagonize such sensing. Here, we performed strand-specific total RNA-Seq on nuclear and cytosolic fractions from cells infected with wild-type IAV or a recombinant IAV lacking NS1, a viral dsRNA-binding protein. Both infections led to global increases in host TE RNAs with bioinformatic and experimental evidence for double-strandedness. However, only NS1-deficient IAV infection led to significant amounts of TE-dsRNAs translocating to the cytosol, and co-precipitations identified that wild-type NS1 associates with TE-dsRNAs. Furthermore, a functional screen indicated that TE-dsRNAs can be engaged by various host cytosolic RNA sensors, including RIG-I, MDA5, ZBP1, and PKR. Our data reveal the double-stranded nature of infection-triggered host TEs and suggest an NS1-mediated sequestration mechanism to limit their cytosolic abundance and broad activation of diverse sensors.

immunology↗

bioRxiv2023

Proximal protein landscapes of the type I interferon signaling cascade reveal negative regulation by the E3 ubiquitin ligase PJA2

Deciphering the intricate dynamic events governing type I interferon (IFN) signaling is critical to unravel key regulatory mechanisms in host antiviral defense. Here, we leveraged TurboID-based proximity labeling coupled with affinity purification-mass spectrometry to comprehensively map the proximal proteomes of all seven canonical human type I IFN signaling cascade members under basal and IFN-stimulated conditions. This established a network of 103 proteins in close proximity to the core members IFNAR1, IFNAR2, JAK1, TYK2, STAT1, STAT2, and IRF9. We validated several known constitutive protein assemblies, while also revealing novel stimulus-dependent and -independent associations between key signaling molecules. Functional screening further identified PJA2 as a negative regulator of IFN signaling via its E3 ubiquitin ligase activity. Mechanistically, PJA2 interacts with the Janus kinases, TYK2 and JAK1, and promotes their non-lysine and non-degradative ubiquitination, resulting in restrained downstream STAT signaling. Our high-resolution proximal protein landscapes provide global insights into the type I IFN signaling network, and serve as a valuable resource for future exploration of its functional complexities.

immunology↗

bioRxiv2021

Combined computational and cellular screening identifies synergistic inhibition of SARS-CoV-2 by lenvatinib and remdesivir

Rapid repurposing of existing drugs as new therapeutics for COVID-19 has been an important strategy in the management of disease severity during the ongoing SARS-CoV-2 pandemic. Here, we used high-throughput docking to screen 6000 compounds within the DrugBank library for their potential to bind and inhibit the SARS-CoV-2 3CL main protease, a chymotrypsin-like enzyme that is essential for viral replication. For 19 candidate hits, parallel in vitro fluorescence-based protease-inhibition assays and Vero-CCL81 cell-based SARS-CoV-2 replication-inhibition assays were performed. One hit, diclazuril (an investigational anti-protozoal compound), was validated as a SARS-CoV-2 3CL main protease inhibitor in vitro (IC50 value of 29 {micro}M) and modestly inhibited SARS-CoV-2 replication in Vero-CCL81 cells. Another hit, lenvatinib (approved for use in humans as an anti-cancer treatment), could not be validated as a SARS-CoV-2 3CL main protease inhibitor in vitro, but serendipitously exhibited a striking functional synergy with the approved nucleoside analogue remdesivir to inhibit SARS-CoV-2 replication, albeit this was specific to Vero-CCL81 cells. Lenvatinib is a broadly-acting host receptor tyrosine kinase (RTK) inhibitor, but the synergistic effect with remdesivir was not observed with other approved RTK inhibitors (such as pazopanib or sunitinib), suggesting that the mechanism-of-action is independent of host RTKs. Furthermore, time-of-addition studies revealed that lenvatinib/remdesivir synergy probably targets SARS-CoV-2 replication subsequent to host-cell entry. Our work shows that combining computational and cellular screening is a means to identify existing drugs with repurposing potential as antiviral compounds. Future studies could be aimed at understanding and optimizing the lenvatinib/remdesivir synergistic mechanism as a therapeutic option.

microbiology↗

bioRxiv2021

Genome-Wide CRISPR Screening Identifies BRD9 as a Druggable Component of Interferon-Stimulated Gene Expression and Antiviral Activity

Transient interferon (IFN) induction of IFN-stimulated genes (ISGs) creates a formidable protective antiviral state. However, loss of appropriate control mechanisms can result in constitutive pathogenic ISG upregulation. Here, we used genome-wide loss-of-function screening to establish genes critical for IFN signaling, identifying all expected members of the JAK-STAT pathway and the previously unappreciated bromodomain-containing protein 9 (BRD9), a defining subunit of non-canonical BAF (ncBAF) chromatin remodeling complexes. Genetic knock-out or small-molecule mediated degradation of BRD9 limited IFN-induced expression of a subset of ISGs in multiple cell-types, and prevented IFN from exerting full antiviral activity against several RNA and DNA viruses. Mechanistically, BRD9 acts at the level of ISG transcription, exhibits a proximal association with STAT2 following IFN stimulation, and relies on its intact acetyl-binding bromodomain and unique ncBAF scaffolding function for activity. Given its druggability, BRD9 may be an attractive target for dampening constitutive ISG expression under certain pathogenic autoinflammatory conditions.

immunology↗

bioRxiv2020

Distinct Phenotypes of SARS-CoV-2 Isolates Reveal Viral Traits Critical for Replication in Primary Human Respiratory Cells

Since entering the human population, SARS-CoV-2 (the causative agent of COVID-19) has spread worldwide, causing >100 million infections and >2 million deaths. While large-scale sequencing efforts have identified numerous genetic variants in SARS-CoV-2 during its circulation, it remains largely unclear whether many of these changes impact adaptation, replication or transmission of the virus. Here, we characterized 14 different low-passage replication-competent human SARS-CoV-2 isolates representing all major European clades observed during the first pandemic wave in early 2020. By integrating viral sequencing data from patient material, virus stocks, and passaging experiments, together with kinetic virus replication data from non-human Vero-CCL81 cells and primary differentiated human bronchial epithelial cells (BEpCs), we observed several SARS-CoV-2 features that associate with distinct phenotypes. Notably, naturally-occurring variants in Orf3a (Q57H) and nsp2 (T85I) were associated with poor replication in Vero-CCL81 cells but not in BEpCs, while SARS-CoV-2 isolates expressing the Spike D614G variant generally exhibited enhanced replication abilities in BEpCs. Strikingly, low-passage Vero-derived stock preparation of 3 SARS-CoV-2 isolates selected for substitutions at positions 5/6 of E, and were highly attenuated in BEpCs, revealing a key cell-specific function to this region. Rare isolate-specific deletions were also observed in the Spike furin-cleavage site during Vero-CCL81 passage, but these were rapidly selected against in BEpCs, underscoring the importance of this site for SARS-CoV-2 replication in primary human cells. Overall, our study uncovers sequence features in SARS-CoV-2 variants that determine cell-specific virus replication, and highlights the need to monitor SARS-CoV-2 stocks carefully when phenotyping newly emerging variants or potential variants-of-concern.

microbiology↗