Biology subjects

Beatty, P. R.

Publications and source records attributed to Beatty, P. R..

4 recordsLinked to original sources

bioRxiv2025

Dengue Virus NS1 Binds Ephrin B1 to Trigger Endothelial Dysfunction

Dengue virus (DENV), a member of the Flaviviridae family, is the most prevalent and medically important mosquito-borne viral pathogen. Infected cells secrete the viral non-structural protein 1 (NS1) into the bloodstream, where it can interact with endothelial cells to induce vascular leak. Host factors involved in NS1-mediated endothelial dysfunction are incompletely understood, leading us to investigate the host interactome of DENV NS1 in endothelial cells via a comparative mass spectrometry approach. We identified ephrin B1 (EFNB1) as a critical host factor in NS1-mediated endothelial barrier dysfunction and show that phosphorylation of EFNB1 is necessary for induction of barrier dysfunction. Further, we map the interface of the EFNB1-NS1 complex through biochemical and computational approaches, and we show that EFNB1-Fc-fusion proteins can act as decoys to block NS1-induced barrier dysfunction in vitro and in vivo. This study provides insights into the mechanism of flavivirus NS1-mediated endothelial barrier dysfunction and new avenues to target vascular leak.

microbiology↗

bioRxiv2025

Therapeutic Potential of Cyclodextrins Targeting Dengue Virus and SARS-CoV-2 Infection and Pathogenesis

Cyclodextrins (CDs) are cyclic oligosaccharides with promising therapeutic applications, including antiviral activity. During viral infections, pathogenesis arises not only from viral replication but also from viral proteins that act as "toxins", disrupting cellular barriers and inducing endothelial dysfunction, a hallmark of severe diseases such as dengue and COVID-19. Dengue virus (DENV) NS1 and SARS-CoV-2 Spike proteins induce endothelial hyperpermeability, contributing to severe complications. Here we explored the potential of a panel of 18 CDs in mitigating endothelial dysfunction caused by these viral proteins and evaluated the CDs antiviral activity in vitro and in vivo. The effect of CDs on endothelial hyperpermeability was assessed using a trans-endothelial electrical resistance assay with human pulmonary microvascular endothelial cells exposed to DENV NS1 and SARS-CoV-2 Spike proteins. Antiviral efficacy of CDs was evaluated in Vero cells infected with DENV2 and Calu-3 cells infected with SARS-CoV-2, and in vivo protection was assessed in a lethal DENV2 mouse model. CDs effectively inhibited DENV NS1-induced endothelial hyperpermeability in vitro, demonstrating their potential to counteract NS1-mediated barrier disruption. In the murine model, CD1 treatment provided partial protection against DENV-induced morbidity and mortality. Further, CDs significantly reduced SARS-CoV-2 infection in vitro and inhibited Spike-induced endothelial dysfunction. These findings indicate that CDs can prevent endothelial hyperpermeability induced by DENV NS1 and SARS-CoV-2 Spike proteins and exhibit antiviral activity against SARS-CoV-2, positioning them as promising candidates for mitigating endothelial complications associated with viral infections. Further research is needed to explore the clinical relevance of CDs and their mechanisms of action.

microbiology↗

bioRxiv2024

Flavivirus NS1-triggered endothelial dysfunction promotes virus dissemination

The Flaviviridae are a family of viruses that include the important arthropod-borne human pathogens dengue virus (DENV), West Nile virus, Zika virus, Japanese encephalitis virus, and yellow fever virus. Flavivirus nonstructural protein 1 (NS1) is essential for virus replication but is also secreted from virus-infected cells. Extracellular NS1 acts as a virulence factor during flavivirus infection in multiple ways, including triggering endothelial dysfunction and vascular leak via interaction with endothelial cells. While the role of NS1 in inducing vascular leak and exacerbating pathogenesis is well appreciated, if and how NS1-triggered endothelial dysfunction promotes virus infection remains obscure. Flaviviruses have a common need to disseminate from circulation into specific tissues where virus-permissive cells reside. Tissue-specific dissemination is associated with disease manifestations of a given flavivirus, but mechanisms dictating virus dissemination are unclear. Here we show that NS1-mediated endothelial dysfunction promotes virus dissemination in vitro and in vivo. In mouse models of DENV infection, we show that anti-NS1 antibodies decrease virus dissemination, while the addition of exogenous NS1 promotes virus dissemination. Using an in vitro system, we show that NS1 promotes virus dissemination in two distinct ways: (1) promoting crossing of barriers and (2) increasing infectivity of target cells in a tissue- and virus-specific manner. The capacity of NS1 to modulate infectivity correlates with a physical association between virions and NS1, suggesting a potential NS1-virion interaction. Taken together, our study indicates that flavivirus NS1 promotes virus dissemination across endothelial barriers, providing an evolutionary basis for virus-triggered vascular leak. Author SummaryThe Flaviviridae contain numerous medically important human pathogens that cause potentially life-threatening infections. Over half of the worlds population is at risk of flavivirus infection, and this number is expected to increase as climate change expands the habitats of the arthropod vectors that transmit these flaviviruses. There are few effective vaccines and no therapeutics approved for prevention or treatment of flavivirus infection, respectively. Given these challenges, understanding how and why flaviviruses cause pathogenesis is critical for identifying targets for therapeutic intervention. The secreted nonstructural protein 1 (NS1) of flaviviruses is a conserved virulence factor that triggers endothelial dysfunction in a tissue-specific manner. It is unknown if this endothelial dysfunction provides any benefit for virus infection. Here we provide evidence that NS1-triggered endothelial dysfunction facilitates virus crossing of endothelial barriers and augments infection of target cells in vitro and promotes virus dissemination in vivo. This study provides an evolutionary explanation for flaviviruses evolving the capacity to trigger barrier dysfunction and highlights NS1 and the pathways governing endothelial dysfunction, as therapeutic targets to prevent flavivirus dissemination.

microbiology↗

bioRxiv2021

SARS-CoV-2 Spike triggers barrier dysfunction and vascular leak via integrins and TGF-β signaling

Severe COVID-19 is associated with epithelial and endothelial barrier dysfunction within the lung as well as in distal organs. While it is appreciated that an exaggerated inflammatory response is associated with barrier dysfunction, the triggers of this pathology are unclear. Here, we report that cell-intrinsic interactions between the Spike (S) glycoprotein of SARS-CoV-2 and epithelial/endothelial cells are sufficient to trigger barrier dysfunction in vitro and vascular leak in vivo, independently of viral replication and the ACE2 receptor. We identify an S-triggered transcriptional response associated with extracellular matrix reorganization and TGF-{beta} signaling. Using genetic knockouts and specific inhibitors, we demonstrate that glycosaminoglycans, integrins, and the TGF-{beta} signaling axis are required for S-mediated barrier dysfunction. Our findings suggest that S interactions with barrier cells are a contributing factor to COVID-19 disease severity and offer mechanistic insight into SARS-CoV-2 triggered vascular leak, providing a starting point for development of therapies targeting COVID-19 pathogenesis.

microbiology↗