Project description:Removing cellular transfer RNAs (tRNAs), making their cognate codons unreadable, creates a genetic firewall that prevents viral replication and horizontal gene transfer. However, numerous viruses and mobile genetic elements encode parts of the translational apparatus, including tRNAs, potentially rendering a genetic-code-based firewall ineffective. In this paper, we show that such horizontally transferred tRNA genes can enable viral replication in Escherichia coli cells despite the genome-wide lack of three codons and the previously essential cognate tRNAs and release factor 1. By repurposing viral tRNAs, we then develop recoded cells bearing an amino-acid-swapped genetic code that reassigns two of the six serine codons to leucine during translation. This amino-acid-swapped genetic code renders cells completely resistant to viral infections by mistranslating viral proteomes and prevents the escape of synthetic genetic information by engineered reliance on serine codons to produce leucine-requiring proteins. Finally, we also repurpose the third free codon to biocontain this virus-resistant host via dependence on an amino acid not found in nature.
Project description:Cytokine storm during respiratory viral infection is an indicator of disease severity and poor prognosis. Type 1 interferon (IFN-I) production and signaling have been reported to be causal in cytokine storm associated pathology in several respiratory viral infections, however, the mechanisms by which IFN-I promotes disease pathogenesis remain poorly understood. We report using Usp18-deficient, USP18 enzymatic inactive and Isg15-deficient mouse models that lack of deISGylation during persistent viral infection leads to severe immune pathology characterized by hematological disruptions, cytokine amplification, lung vascular leakage and death. Transcriptional studies of immune cells from mice bearing the enzymatic inactive version of USP18 (Usp18C61A) revealed a neutrophil influx in the lung of these animals during infection, associated with increased immature neutrophil content. These neutrophil differentiation changes were dependent on ISG15 as deletion of Isg15 from C61A animals reversed the accumulation of immature neutrophils. Importantly, neutrophil depletion reversed morbidity and mortality in Usp18C61A mice. In summary, we reveal Usp18 enzymatic function is crucial for regulating extracellular release of ISG15 which are accompanied by altered neutrophil differentiation, cytokine amplification and mortality following persistent viral infection.
Project description:Global endemic infections, such as leptospirosis, rickettsial diseases, and dengue infections present diagnostic challenges, posing a dilemma for antibiotic stewardship worldwide. The goal of this project was to identify accurate transcriptional classifiers able to discriminate between bacterial and viral illness of global pathogens.
Project description:We present evidence that (1) viral respiratory infections are potential mechanisms of ACE2 overexpression in patients with asthma and (2) ACE activation regulates multiple cytokine anti-viral responses that could explain a mechanism for cytokine surge and associated tissue damage. These results suggest that the recent finding of severe COVID-19 in asthma patients with recent exacerbations may be attributable to synergistic biomolecular interactions with viral co-infections.
Project description:Coronavirus disease 2019 (Covid19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is associated with lung inflammation and respiratory failure. In a prospective multi-country cohort of Covid19 patients, we found that increased Notch4 expression on circulating Treg cells was associated with increased disease severity, predicted mortality, and declined upon recovery. Deletion of Notch4 in Treg cells or therapy with anti-Notch4 antibodies in conventional and humanized mice suppressed the dysregulated innate immune response and rescued disease morbidity and mortality induced by a synthetic analogue of viral RNA or by the influenza H1N1 virus in an amphiregulin-dependent manner. Notably, amphiregulin production declined in Covid19 subjects as a function of disease severity and Notch4 expression. These results identify Notch4 as an immune regulatory switch that licenses virus-induced lung inflammation by altering Treg cell-mediated tissue repair. They also suggest Notch4 as a therapeutic target in Covid19 and other respiratory viral infections.