Biology subjects

Nash, D. A.

Publications and source records attributed to Nash, D. A..

4 recordsLinked to original sources

bioRxiv2026

Herpes simplex virus pUL56 abolishes neuronal activity by removing voltage-gated ion channels from the plasma membrane

Herpes simplex virus 1 (HSV-1) infections of the central nervous system cause encephalitis and are associated with increased risk of neurodegeneration, yet the molecular consequences of lytic infection in human neurones remain incompletely defined. We map the transcriptomic, proteomic and surface-proteome changes induced by HSV-1 across the lytic infection cycle in human iPSC-derived cortical glutamatergic neurones. HSV-1 drives extensive plasma-membrane remodelling, including the removal of voltage-gated sodium, potassium and calcium channels, resulting in a profound loss of synchronous calcium signalling. We identify the viral ubiquitin-ligase adaptor pUL56 as the principal effector of this process: pUL56-dependent depletion of ion channels abolishes coordinated calcium signalling, whereas deletion or mutation of its E3-ligase binding motifs preserves synchrony. Furthermore, expression of pUL56 alone is sufficient to abolish neuronal electrical activity. These findings establish pUL56 as a potent viral suppressor of neuronal excitability and provide potential mechanistic links between HSV-1 infection and neurodegenerative pathology.

microbiology↗

bioRxiv2026

Human iPSC Models of Ganglioside Deficiency Reveal a Sialylated Lipid Requirement for Plasma-Membrane Organization and Neuronal Activity

Gangliosides are abundant neuronal glycosphingolipids, yet their roles in organizing the plasma membrane and supporting neuronal function remain poorly defined. Mutations in the biosynthetic enzymes ST3GAL5 or B4GALNT1 cause severe neurodevelopmental disorders, yet their cellular consequences are unclear. Using isogenic human iPSC-derived cortical neurons, we show that loss of these enzymes eliminates major neuronal gangliosides but produces strikingly divergent outcomes. ST3GAL5 deficiency reprograms the glycosphingolipid repertoire toward non-neuronal species and abolishes network-level electrical activity. In contrast, B4GALNT1-deficient neurons retain near-normal excitability, supported by accumulation of simple sialylated precursors (GM3/GD3). Quantitative proteomics reveals a profound loss of plasma membrane proteins, including ion channels and synaptic organizers, only in ST3GAL5-deficient neurons. These findings identify sialylated glycosphingolipids as essential scaffolds for plasma membrane organization and neuronal excitability, providing a mechanistic basis for the severe phenotype caused by loss of GM3 synthase in humans. TEASERHuman neuronal models reveal why loss of GM3 synthase causes severe neurodevelopmental disease

cell biology↗

bioRxiv2025

Optimisation of lytic herpes simplex virus infection in human induced pluripotent stem cell derived cortical neurones

Herpes simplex virus (HSV)-1 infection of cortical neurones is a leading cause of encephalitis. While we have substantial knowledge about the molecular virology of HSV-1 lytic infection in cells of the periphery, like keratinocytes or fibroblasts, we know much less about infection of human neurones owing to the challenges of working with neuronal cell-based models. Here we demonstrate the use of a human induced pluripotent stem cell (iPSC)-derived cortical neurone model (i3Neurones) for HSV-1 infection. i3Neurones are highly scalable and can be rapidly and efficiently differentiated into an isogenic population of cortical glutamatergic neurones. We show that i3Neurones support the full HSV-1 lytic replication cycle. We present an optimised protocol for the infection of i3Neurones with HSV-1 that allows their synchronous infection at near-100% efficiency, and optimised fixation methods that preserves organelle and neurite structure for immunocytochemistry analysis. Our study highlights i3Neurones as a robust, scalable platform for microscopy and biochemical studies of HSV-1 and other neurotropic pathogens. Data summaryThe authors confirm all supporting data, code and protocols have been provided within the article or through supplementary data files.

microbiology↗

bioRxiv2025

Flexibility and modulation of translation initiation in enterovirus genomes

Enteroviruses comprise a large group of mammalian pathogens that often utilize two open reading frames (ORFs) to encode their proteins: the upstream protein (UP) and the main polyprotein. In some enteroviruses, in addition to the canonical upstream AUG (uAUG), there is another AUG that may represent an alternative upstream initiation site. An analysis of enterovirus sequences containing additional upstream AUGs identified several clusters, including strains of pathogenic Enterovirus alphacoxsackie and E. coxsackiepol. Using ribosome profiling on coxsackievirus CVA-13 (E. coxsackiepol), we demonstrate that both upstream AUG codons can be used for translation initiation in infected cells. Moreover, we confirm translation from both upstream AUGs using a reporter system. Mutating the additional upstream AUG in the context of CVA-13 did not result in phenotypic changes in immortalized cell lines. However, the wild-type virus outcompeted this mutant in human intestinal organoids and differentiated neuronal systems, representing an advantage in physiologically relevant infection sites. Mutation of the stop codon of the shorter upstream ORF led to dysregulated translation of the other ORFs in the reporter system, suggesting a potential role for the additional uORF in modulating the expression level of the other ORFs. These findings demonstrate the remarkable plasticity of enterovirus IRES-mediated initiation and the competitive advantage of double-upstream-AUG-containing viruses in terminally differentiated intestinal organoids and neuronal systems.

microbiology↗