Biology subjects

Pearson, H. M.

Publications and source records attributed to Pearson, H. M..

3 recordsLinked to original sources

bioRxiv2026

Screening of MMV open-source libraries using Bunyamwera virus as a model reveals inhibitors of Oropouche virus infection

Arboviral infections remain a major public health concern in tropical and subtropical regions, where environmental and socioeconomic conditions facilitate the circulation of diverse RNA viruses, including over 350 members of the recently renamed Peribunyaviridae family. In this regard, Oropouche virus (OROV) has caused explosive outbreaks in the Amazon region and shows wider distribution in Brazil, with confirmed neurological infections and fatalities in 2024. The absence of effective antiviral therapies highlights an urgent need for the discovery of anti-OROV drugs. In this work we evaluated the antiviral potential of the Pandemic Response Box and Global Health Priority Box libraries from Medicines for Malaria Venture (MMV) against OROV, using a well-established Bunyamwera virus (BUNV) system, widely used as a prototype of the Peribunyaviridae family, expressing the reporter gene eGFP. A screening protocol based on fluorescent reporter gene detection by live cell imaging was employed. 9 compounds were identified with significant activity against BUNV-eGFP with 3 being highlighted as the most promising hits: Trimetrexate, GSK-983 and MMV1634385. These compounds were validated by testing for activity against OROV, and in these assays, GSK-983 exhibited the lowest EC50 value and consequently the highest selectivity index. Future studies should evaluate the antiviral efficacy of GSK-983 and assess its pharmacokinetic profile. Furthermore, our results indicate that our approach employing BUNV-eGFP as a model against OROV can lead to the discovery of promising and interesting hit compounds, thereby providing a validated screening approach for future antivirals against Oropouche fever.

microbiology↗

bioRxiv2026

Host cell potassium ion channels KCNJ2 (KIR2.1), KCNJ13 (KIR7.1) and KCNMA1 (BKCa) mediate escape of Bunyamwera virus from late endosomal compartments

The Orthobunyavirus genus within the Peribunyaviridae family of enveloped arthropod-borne negative-sense RNA viruses includes species associated with serious or fatal disease in both animals and humans such as Schmallenberg, La Crosse and Oropouche viruses. Orthobunyaviruses (OBVs) are internalised into cells by endocytosis and release their genomes following fusion with late endosomal (LE) membranes, triggered by low pH of the luminal milieu. There is mounting evidence to suggest OBV endosomal escape is also influenced by potassium ions (K+), which increase in concentration as endosomes mature. Endosomal K+ flux is controlled by cellular K+ channels, and we previously showed that K+ channel blockade using broad spectrum pharmacological inhibition abrogates OBV infection, with virions trapped within the endosomes. However, the K+ channels regulating this process are unknown. Herein, to identify the K+ channels involved, we studied Bunyamwera virus (BUNV), the prototypical OBV, and screened a siRNA library targeting 342 human ion channels. We identified 19 K+ channels whose knockdown inhibited BUNV gene expression by over 50%, with at least seven channels affecting BUNV at the entry stage, suggesting they exert a combinatorial influence. Of these seven channels, we used both pharmacological inhibition and genetic channel manipulation to show that OBV escape from CD63- and Rab7-positive LEs is controlled by KCNJ2 (KIR2.1), KCNJ13 (KIR7.1) and KCNMA1 (BKCa). These studies add to the understanding of host factors influencing OBV entry, regulation of endosomal ion flux, and could aid in the design or repurposing of therapeutics for the treatment of OBV-associated disease.

cell biology↗

bioRxiv2025

The orthobunyavirus Gc glycoprotein head and stalk drives an infectious virion assembly pathway that is specific for the insect host

The Orthobunyavirus genus of arthropod-borne segmented RNA viruses comprises several important pathogens including the human-infecting Oropouche virus and animal-infecting Schmallenberg virus (SBV). The prototypical Bunyamwera orthobunyavirus (BUNV) possesses envelope-embedded glycoprotein spikes, with Gc head and stalk domains forming distinctive tripods covering the envelope-proximal Gn. Spike ectodomains mediate virus entry, while endodomains interact with nucleoprotein (NP) enwrapped genome segments to mediate virion assembly. Interestingly, BUNV Gc head/stalk domains are redundant for virus growth in mammalian cells, consistent with isolations of SBV from animals bearing head/stalk deletions. However, orthobunyavirus isolations from arthropods in nature appear to maintain these domains strictly. To investigate this discrepancy, we compared the multiplication characteristics of wildtype BUNV (BUNV-WT) with a Gc head/stalk deleted BUNV (BUNV-{Delta}7). In mammalian cells BUNV-WT and BUNV-{Delta}7 grew to equivalent titres, whereas BUNV-{Delta}7 titres from insect cells were 1000-fold lower than BUNV-WT and strikingly produced no virions following blood meal infection of Aedes mosquitoes. To understand this insect-specific restriction in virion production, we showed the intracellular abundance of BUNV-WT and BUNV-{Delta}7 Gc and NP components were equivalent, suggesting {Delta}7-Gc was assembly-deficient. To explore this, we investigated Gc and {Delta}7-Gc interactions during BUNV-WT and BUNV-{Delta}7 infections of both insect and mammalian cells by co-immunoprecipitation and multiplex mass spectrometry, revealing {Delta}7-Gc exhibited markedly reduced NP interactions in insect cells. We propose Gc recruits genome segments during virion assembly and that the complete Gc head/stalk assembly is maintained in nature due to its essential role in the insect host. IMPORTANCEOrthobunyaviruses are arthropod-borne viruses that cause severe disease in humans and animals, including congenital malformations and abortions. Orthobunyavirus Gn and Gc glycoproteins form spikes, which mediate entry and genome recruitment during assembly. In nature, OBVs bearing large deletions within Gc head/stalk domains have been isolated from animals, yet the head/stalk domains appear to be strictly maintained within insects. To investigate this discrepancy, we compared the multiplication of Bunyamwera orthobunyavirus (BUNV-WT) with head/stalk-deleted variant (BUNV-{Delta}7). In mammalian cells both viruses reached similar titres, but strikingly BUNV-{Delta}7 failed to produce virions in both insect cells and Aedes mosquitoes. We showed this was because BUNV-{Delta}7 failed to assemble new virions, revealing its head/stalk-deleted Gc was deficient in interactions with genome components. We propose that Gc drives species-specific interactions with genome segments during virion assembly, explaining why Gc head/stalk domains are conserved in nature due to their essential role in the insect host.

microbiology↗