Martin Stacey

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 (K _IR 2.1), KCNJ13 (K _IR 7.1) and KCNMA1 (BK _Ca ). 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.

BACKGROUND: Chemical insecticides are an important tool to control damaging pest infestations. However, lack of species specificity, the rise of resistance and the demand for biological alternatives with improved ecotoxicity profiles means that chemicals with new modes of action are required. RNA interference (RNAi)‐based strategies using double‐stranded RNA (dsRNA) as a species‐specific bio‐insecticide offer an exquisite solution that addresses these issues. Many species, such as the fruit pest Drosophila suzukii, do not exhibit RNAi when dsRNA is orally administered due to degradation by gut nucleases and slow cellular uptake pathways. Thus, delivery vehicles that protect and deliver dsRNA are highly desirable.RESULTS: In this work, we demonstrate the complexation of D. suzukii‐specific dsRNA for degradation of vha26 mRNA with bespoke diblock copolymers. We study the ex vivo protection of dsRNA against enzymatic degradation by gut enzymes, which demonstrates the efficiency of this system. Flow cytometry then investigates the cellular uptake of Cy3‐labelled dsRNA, showing a 10‐fold increase in the mean fluorescence intensity of cells treated with polyplexes. The polymer/dsRNA polyplexes induced a significant 87% decrease in the odds of survival of D. suzukii larvae following oral feeding only when formed with a diblock copolymer containing a long neutral block length (1:2 cationic block/neutral block). However, there was no toxicity when fed to the closely related Drosophila melanogaster.CONCLUSION: We provide evidence that dsRNA complexation with diblock copolymers is a promising strategy for RNAi‐based species‐specific pest control, but optimisation of polymer composition is essential for RNAi success. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

The hepatitis B core protein (HBc) forms noninfectious virus-like particles, which can be modified to present a capturing molecule, allowing suitably tagged antigens to be bound on their surface. This system can be adapted and provides the foundation for a universal “bolt-on” vaccine platform (termed VelcroVax) that can be easily and rapidly modified to generate nanoparticle vaccine candidates.

Elafin, an elastase specific protease inhibitor, is well described to be upregulated in lesional psoriatic skin. Elastase is active in antimicrob | POSTER

Summary: Type I fatty acid synthases (FASs) are critical metabolic enzymes which are common targets for bioengineering in the production of biofuels and other products. Serendipitously, we identified FAS as a contaminant in a cryoEM dataset of virus-like particles (VLPs) purified from P. pastoris , an important model organism and common expression system used in protein production. From these data, we determined the structure of P. pastoris FAS to 3.1 Å resolution. While the overall organisation of the complex was typical of type I FASs, we identified several differences in both structural and enzymatic domains through comparison with the prototypical yeast FAS from S. cerevisiae . Using focussed classification, we were also able to resolve and model the mobile acyl-carrier protein (ACP) domain, which is key for function. Ultimately, the structure reported here will be a useful resource for further efforts to engineer yeast FAS for synthesis of alternate products.

Protection against microbial infection by the induction of inflammation is a key function of the IL-1 superfamily, including both classical IL-1 and the new IL-36 cytokine families. Candida albicans is a frequent human fungal pathogen causing mucosal infections. Although the initiators and effectors important in protective host responses to C. albicans are well described, the key players in driving these responses remain poorly defined. Recent work has identified a central role played by IL-1 in inducing innate Type-17 immune responses to clear C. albicans infections. Despite this, lack of IL-1 signaling does not result in complete loss of immunity, indicating that there are other factors involved in mediating protection to this fungus. In this study, we identify IL-36 cytokines as a new player in these responses. We show that C. albicans infection of the oral mucosa induces the production of IL-36. As with IL-1α/β, induction of epithelial IL-36 depends on the hypha-associated peptide toxin Candidalysin. Epithelial IL-36 gene expression requires p38-MAPK/c-Fos, NF-κB, and PI3K signaling and is regulated by the MAPK phosphatase MKP1. Oral candidiasis in IL-36R^−/− mice shows increased fungal burdens and reduced IL-23 gene expression, indicating a key role played by IL-36 and IL-23 in innate protective responses to this fungus. Strikingly, we observed no impact on gene expression of IL-17 or IL-17–dependent genes, indicating that this protection occurs via an alternative pathway to IL-1–driven immunity. Thus, IL-1 and IL-36 represent parallel epithelial cell–driven protective pathways in immunity to oral C. albicans infection.