Biology subjects

Jackson, K.

Publications and source records attributed to Jackson, K..

At least 19 recordsLinked to original sources

bioRxiv2026

Precocious maturation and Purkinje cell dysfunction in the mouse Chd8 haploinsufficient cerebellum

The cerebellum plays an emerging, but understudied, role in neurodevelopmental disorders (NDDs). Mutations in CHD8 cause a monogenic NDD (CHD8-NDD) characterized by autism and other manifestations, and prior work in Chd8 mutant mice reported cerebellar abnormalities, raising the possibility of cerebellar contribution to CHD8-NDD. To comprehensively characterize the impact of Chd8 haploinsufficiency on cerebellar development and function, we profiled the postnatal day 12 (P12) cerebellum of germline Chd8+/- mice using transcriptomic, morphological, and electrophysiological approaches. Gross cerebellar morphology was unaffected, but single-nucleus RNA sequencing revealed transcriptomic signatures of pathophysiology across cell types, including accelerated maturation of molecular layer interneurons and granule cells, and altered myelination state of oligodendrocytes. Purkinje cells (PCs) showed the strongest transcriptomic burden of any cell type and, consistent with this, exhibited altered morphology and electrophysiological properties. Bulk RNA sequencing confirmed that transcriptomic pathology persists into adulthood, indicating lasting impacts on both neuronal and glial gene expression. Together, these results capture cell-type-specific cerebellar perturbations associated with Chd8 haploinsufficiency and support the cerebellum as a relevant site of pathology in CHD8-NDD.

neuroscience↗

bioRxiv2026

Single-cell multi-omics maps clonal IEL expansion and epithelial remodelling in refractory coeliac disease

Background Refractory coeliac disease type 1 (RCD1) lacks defining molecular markers, and the immune and epithelial mechanisms sustaining intestinal injury remain poorly understood. Objective To define the clonal immune and epithelial states that distinguish RCD1 from active coeliac disease (ACD) and determine their spatial organisation in the duodenal mucosa. Design We integrated single-cell RNA sequencing, CITE-seq surface proteomics and paired T-cell receptor sequencing of duodenal immune and epithelial compartments from Healthy controls (n = 6), ACD (n = 7), RCD1 (n = 9) and RCD2 (n = 2), with spatial transcriptomics in a subset of biopsies. Results RCD1 showed widespread TCR{beta} and TCR{gamma}{delta} clonal expansion across multiple IEL states, extending beyond previously defined mutation-bearing aberrant clones. Distinct IEL populations converged on a shared programme of adaptive persistence, innate-like signalling, metabolic fitness and cytoskeletal remodelling; GZMK expression marked both clonally expanded and non-clonal disease-associated states. In parallel, RCD1 epithelium showed loss of mature absorptive cell states and expansion of stress-associated, immune-interacting and regenerative programmes. Transit-amplifying cells acquired differentiation and tissue-remodelling signatures, while enteroendocrine cells expanded and developed a sensory-neurosecretory programme involving TRPA1, TRPV1, vesicle trafficking and NEUROD1 regulon activity. Spatial transcriptomics localised regenerative and enteroendocrine-associated epithelial programmes adjacent to immune-visible epithelial regions and KLRK1/GZMK-expressing IEL-rich niches in refractory tissue. Conclusion RCD1 represents a distinct mucosal state characterised by coordinated clonal IEL adaptation and epithelial remodelling, rather than simple amplification of ACD, providing a cellular framework for persistent tissue injury and disease stratification.

immunology↗

bioRxiv2026

Site-specific combinatorial ubiquitination drives the targeted degradation of plasma membrane proteins

Cullin-RING E3 ligases (CRLs) ubiquitinate their substrates by recruiting them to complexes containing ubiquitin-conjugating enzymes (UCEs). Ubiquitination proceeds through the transfer of ubiquitin from UCEs to substrate lysines, but the specificity of lysine ubiquitination has not been widely investigated in cells. In this study, we use global ubiquitination profiling to identify sites in the kinase domains of receptor tyrosine kinases (RTKs), EGFR and Her2, that undergo CRL-mediated ubiquitination in cells treated with heterobifunctional degrader molecules. We find that VHL- and Cereblon-dependent degraders trigger the ubiquitination of a common subset of accessible lysines. Using mutagenesis, we show that the number of available ubiquitination sites specifies the extent of RTK degradation. Furthermore, introduction of non-native sites mostly fails to rescue clearance of lysine-deficient RTK mutants. These results highlight the specificity with which UCEs ubiquitinate their substrates and suggest that the ubiquitination of multiple sites governs the efficacy of degraders targeting plasma membrane proteins.

cell biology↗

bioRxiv2025

DNA Motors Powered by Exonuclease III for Autonomous Rolling Motion and Biosensing Applications

Nucleic acid-based synthetic motors emulate key behaviors of biological machines, enabling applications in biosensing and nanoscale actuation. Among the reported synthetic motors, RNase H-powered motors offer high speed and processivity with demonstrated applications in computation and viral sensing. However, these motors rely on RNA as "fuel" source, limiting their stability. Here, we report the development of a robust, RNA-free DNA motor powered by Exonuclease III. These motors exhibit self-avoiding rolling motion driven by enzymatic hydrolysis of surface-bound DNA fuel strands, consistent with a burnt-bridge Brownian ratchet mechanism of translocation. We systematically optimized motor performance by chemically tuning the fluorescence reporter, DNA sequence composition, and surface fuel density. Fluorescence and brightfield microscopy revealed super-diffusive and Levy-like stop-and-go dynamics under optimized conditions. Importantly, the established DNA-only architecture confers resistance to RNase degradation, and the system can be configured for motion-based biosensing via aptamer-functionalized components that selectively stall in response to viral targets. Beyond the significance of creating a chemically stable, tunable, and biosensing-compatible DNA motor platform, the work also establishes the modularity of the rolling motor platform and highlights how enzymatic diversity can expand their chemical and functional scope.

biophysics↗

bioRxiv2025

MYC modulates TOP2A diffusion to promote substrate detection and activity

Topoisomerases alleviate DNA supercoiling by cleaving and resealing DNA strands. Previously, we showed that the oncoprotein MYC recruits and stimulates topoisomerases to remove DNA entanglements generated by oncogenic transcription. Understanding this mechanism may suggest methods to inhibit MYC-driven topoisomerase activation, targeting tumor-specific transcription. Here, we demonstrate that the essential topoisomerase TOP2A in human cells exists in a dynamic equilibrium between sequestration in the nucleolus, substrate searching in transcription hubs, and active engagement on chromatin. This equilibrium is highly responsive to changes in DNA topology, allowing cells to regulate TOP2A levels. Using single molecule tracking, we show that MYC accelerates TOP2A diffusion in cells. We explain this phenotype by demonstrating that MYC limits TOP2A self-interaction in vitro, while decreasing the size of TOP2A complexes in cells. By increasing TOP2A diffusion, MYC promotes substrate binding and increases TOP2A engagement on chromatin genome-wide, revealing the mechanism underlying MYC stimulation of TOP2A activity.

cell biology↗

bioRxiv2025

Phage intervention improves colitis and response to corticosteroids by attenuating virulence of Crohn's disease-associated bacteria

Adherent-invasive Escherichia coli (AIEC) exhibit proinflammatory properties and have been implicated in the pathogenesis of Crohns disease (CD), a form of inflammatory bowel disease (IBD). Antibiotic use in CD lacks specificity and may worsen microbiome disruption, prompting interest in bacteriophages (phages) for targeted microbiome editing. Here, we identified HER259, a phage active against the clinical AIEC strain NRG857c. Using gnotobiotic models of AIEC-driven colitis, we show that HER259 attenuates AIEC virulence, including suppression of the FimH adhesin through inversion of the fimS promoter to its off orientation. Withdrawal of HER259 treatment leads to reversion of the fimS promoter and reactivated colitis in mice. HER259 phage also enhances the therapeutic effect of sub-therapeutic budesonide, independent of microbial drug metabolism. These findings support targeted phage therapy as an adjunct treatment approach in IBD, demonstrating modulation of bacterial virulence and improved response to conventional treatments which may reduce drug-related side effects. One Sentence SummaryBacteriophage HER259 improves colitis severity mediated by Crohns disease Escherichia coli NRG857c, and increases efficacy of budesonide.

microbiology↗

bioRxiv2025

Hematopoietic Single Cell Atlas Reveals a Diverse Repertoire of Lymphoid Cells in Larval Zebrafish

Embryonic development is a critical time window for the establishment of the hematopoietic and immune systems. During embryogenesis, hematopoietic stem and progenitor cells (HSPCs) that possess divergent differentiation preferences arise and sustain lifelong hematopoiesis. How the pace and differentiation repertoire of native hematopoiesis is set in development and how it evolves as the organism grows is incompletely elucidated. Here, we use temporal lineage tracing of the emerging hematopoietic system during zebrafish development coupled with single cell RNA sequencing to define the origins of larval and adult hematopoietic cells. In both larvae and adult tissues, HSPCs arising earlier during embryogenesis show a predilection for lymphoid lineage production while those arising later are skewed towards erythroid. Moreover, early arising HSPCs are the main contributors to adult tissue resident lymphocytes. Mechanistically, early and late arising HSPCs show divergent transcriptional signatures and differential sensitivities to the levels of the transcription factor Runx1. Additionally, we identified that young larvae possess a more heterogeneous set of lymphoid cells than previously recognized including diverse T-lymphocytes and Innate Lymphoid-like Cells (ILCs). We demonstrated that these newly described larval ILC-like cells reside in lymphoid and mucosal organs and are responsive to viral mimic immune stimulation, indicating their relevance in early vertebrate life. The work provides new fundamental knowledge on how the heterogeneous HSPC pool establishes early immune hierarchies during embryogenesis and its persistence in adulthood.

developmental biology↗

bioRxiv2025

Bacteriophage-Loaded Microneedle Patches for Targeted andMinimally Disruptive Foodborne Pathogen Decontamination

Antibacterial additive use has surged due to rising incidences of food contamination, despite concerns over antibiotic resistance. Bacteriophage (bacterial viruses) represent a unique and promising opportunity as antibacterial agents, offering targeted bacterial lysis while being food safe. However, their commercial success has been limited by the significant diffusion barriers they face within food, preventing effective delivery at contamination sites. Here, we introduce bacteriophage-loaded microneedle patches that enable targeted phage delivery directly within food, eliminating internal pathogens in a minimally disruptive manner. The application of microneedles within food is first explored. The platform is then substantiated by comparing performance in raw beef and cooked chicken, where we achieved up to 3-logs reduction in Escherichia coli, thus providing complete decontamination according to regulatory limits. In contrast, conventional surface application of the same phage failed to provide significant decontamination. To ensure broad applicability, phage cocktails were also loaded into microneedles to demonstrate polymicrobial decontamination against other common food contaminants including Salmonella. This platform can also be adapted to extend food shelf-life by targeting spoilage-inducing bacteria.

bioengineering↗

bioRxiv2025

The mycomembrane differentially and heterogeneously restricts antibiotic permeation

The recalcitrance of Mycobacterium tuberculosis to antibiotic treatment has been broadly attributed to the impermeability of the organisms outer mycomembrane. However, the studies that support this inference have been indirect and/or reliant on bulk population measurements. We previously developed the Peptidoglycan Accessibility Click-Mediated AssessmeNt (PAC-MAN) method to covalently trap azide-modified small molecules in the peptidoglycan cell wall of live mycobacteria, after they have traversed the mycomembrane. Using PAC-MAN we now show that the mycomembrane differentially restricts access of fluorophores and antibiotic derivatives. Mycomembranes of both M. tuberculosis and the model organism M. smegmatis discriminate between divergent classes of antibiotics as well as between antibiotics within a single family, the fluoroquinolones. By analyzing sub-populations of M. tuberculosis and M. smegmatis, we also found that some fluorophores and vancomycin are heterogeneously restricted by the mycomembrane. Our data indicate that the mycomembrane is a molecule- and cell-specific barrier to antibiotic permeation. Abstract Graphic O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=108 SRC="FIGDIR/small/630956v1_ufig1.gif" ALT="Figure 1"> View larger version (35K): org.highwire.dtl.DTLVardef@4bdeb7org.highwire.dtl.DTLVardef@10ade47org.highwire.dtl.DTLVardef@872dceorg.highwire.dtl.DTLVardef@d04b59_HPS_FORMAT_FIGEXP M_FIG C_FIG

microbiology↗

bioRxiv2024

Single-Cell Profiling Reveals Global Immune Responses during the Progression of Murine Epidermal Neoplasms

Immune cells determine the role of the tumor microenvironment during tumor progression, either suppressing tumor formation or promoting tumorigenesis. We analyzed the profile of immune cells in the tumor microenvironment of control mouse skins and skin tumors at the single-cell level. We identified 15 CD45+ immune cell clusters, which broadly represent the most functionally characterized immune cell types including macrophages, Langerhans cells (LC), conventional type 1 dendritic cells (cDC1), conventional type 2 dendritic cells (cDC2), migratory/mature dendritic cells (mDC), dendritic epidermal T cells (DETC), dermal {gamma}{delta} T cells ({gamma}{delta}T), T cells, regulatory T cells (Tregs), natural killer cells (NK), type 2 innate lymphoid cells (ILC2), neutrophils (Neu), mast cells (Mast), and two proliferating populations (Prolif.1 and Prolif.2). Skin tumor progression reprogramed immune cells and led to a marked increase in the relative percentages of macrophages, cDC2, mDC, Tregs, and Neu. Macrophages, the largest cell cluster of immune cells in skin tumors. In addition, macrophages emerged as the predominant communication hub in skin tumors, highlighting the importance of macrophages during skin tumor progression. In contrast, other immune cell clusters decreased during skin tumor progression, including DETC, {gamma}{delta}T, ILC2, and LC. In addition, skin tumor progression dramatically upregulated Jak2/Stat3 expression and the interferon response across various immune cell clusters. Further, skin tumor progression activated T cells and NK cells indicated by elevated expression of IFN-{gamma} and Granzyme B in skin tumors. Meanwhile, a pronounced infiltration of M2-macrophages and Tregs in skin tumors created an immunosuppressive microenvironment, consistent with the elevated expression of the Stat3 pathway in skin tumors. In summary, our study elucidates the immune cell landscape of epidermal neoplasms, offering a comprehensive understanding of the immune response during skin tumor progression and providing new insights into cancer immune evasion mechanisms.

cancer biology↗

bioRxiv2024

Discerning Specific Thrombolytic Activities and Blood Clot Degradomes of Diverse Snake Venoms with Untargeted Peptidomics

Identification and characterization of snake venom toxins that interfere with hemostasis have important implications for the treatment of snake envenomation, the bioprospecting of therapeutically useful molecules, and the development of research tools for investigating hematologic disorders. Many venoms have been shown to possess thrombolytic activity. However, it remains unclear if actions on other clot-stabilizing proteins beyond fibrin chains contribute significantly to venom-induced thrombolysis because the clot-wide targets of venom proteases and the mechanisms responsible for thrombolysis are not well understood. Here, we utilize a high-throughput time-based thrombolysis assay in combination with untargeted peptidomics to provide comprehensive insight into the effects of venom from six snake species on blood clot degradation. We compare thrombolytic profiles across venoms with variable levels of proteases and generate venom-specific fingerprints of cleavage specificity. We also compare the specific effects of venoms that possess a range of thrombolytic activity on fibrin subunits and other clot-bound proteins involved in clot structure. Venoms with higher thrombolytic activity demonstrated an enhanced ability to target multiple sites across fibrin chains critical to clot stability and structure, as well as clot-stabilizing proteins including fibronectin and vitronectin. Collectively, this study significantly expands our understanding of the thrombolytic and fibrinolytic effects of snake venom by determining the full suite of clot-specific venom targets that are involved in clot formation and stability.

pharmacology and toxicology↗

bioRxiv2024

Polyamine Depletion by D, L-alpha-difluoromethylornithine Inhibits Ewing Sarcoma Metastasis by Inducing Ferroptosis

AO_SCPLOWBSTRACTC_SCPLOWPolyamine metabolism and signaling play important roles in multiple cancers but have not previously been studied in Ewing sarcoma. Here, we show that blocking polyamine synthesis with D, L-alpha-difluoromethylornithine (DFMO) causes a G1 cell cycle arrest, dose-dependent decreases in sarcosphere formation from Ewing sarcoma cell lines growing in non-adherent conditions and a decrease in clonogenic growth in soft agar. Further, we utilized our orthotopic implantation/amputation model of Ewing sarcoma metastasis to demonstrate that DFMO slowed primary tumor growth in addition to limiting metastasis. RNA sequencing demonstrated gene expression patterns consistent with induction of ferroptosis caused by polyamine depletion. Induction of ferroptosis was validated in vitro by demonstrating that ferrostatin-1, an inhibitor of ferroptosis, allows sphere formation even in the presence of DFMO. Collectively, these results reveal a novel mechanism by which DFMO prevents metastasis - induction of ferroptosis due to polyamine depletion. Our results provide preclinical justification to test the ability of DFMO to prevent metastatic recurrence in Ewing sarcoma patients at high risk for relapse.

cancer biology↗

bioRxiv2024

scDAPP: a comprehensive single-cell transcriptomics analysis pipeline optimized for cross-group comparison

Single-cell transcriptomics profiling has increasingly been used to evaluate cross-group differences in cell population and cell-type gene expression. This often leads to large datasets with complex experimental designs that need advanced comparative analysis. Concurrently, bioinformatics software and analytic approaches also become more diverse and constantly undergo improvement. Thus, there is an increased need for automated and standardized data processing and analysis pipelines, which should be efficient and flexible too. To address these, we develop the single-cell Differential Analysis and Processing Pipeline (scDAPP), a R-based workflow for comparative analysis of single cell (or nucleus) transcriptomic data between two or more groups and at the levels of single cells or "pseudobulking" samples. The pipeline automates many steps of pre-processing using data-learnt parameters, uses previously benchmarked software, and generates comprehensive intermediate data and final results that are valuable for both beginners and experts of scRNA-seq analysis. Moreover, the analytic reports, augmented by extensive data visualization, increase the transparency of computational analysis and parameter choices, while facilitate users to go seamlessly from raw data to biological interpretation. Availability and ImplementationscDAPP is freely available for non-commercial usage as an R package under the MIT license. Source code, documentation and sample data are available at the GitHub (https://github.com/bioinfoDZ/scDAPP).

bioinformatics↗

bioRxiv2024

The impact of package selection and versioning on single-cell RNA-seq analysis

Standard single-cell RNA-sequencing analysis (scRNA-seq) workflows consist of converting raw read data into cell-gene count matrices through sequence alignment, followed by analyses including filtering, highly variable gene selection, dimensionality reduction, clustering, and differential expression analysis. Seurat and Scanpy are the most widely-used packages implementing such workflows, and are generally thought to implement individual steps similarly. We investigate in detail the algorithms and methods underlying Seurat and Scanpy and find that there are, in fact, considerable differences in the outputs of Seurat and Scanpy. The extent of differences between the programs is approximately equivalent to the variability that would be introduced in benchmarking scRNA-seq datasets by sequencing less than 5% of the reads or analyzing less than 20% of the cell population. Additionally, distinct versions of Seurat and Scanpy can produce very different results, especially during parts of differential expression analysis. Our analysis highlights the need for users of scRNA-seq to carefully assess the tools on which they rely, and the importance of developers of scientific software to prioritize transparency, consistency, and reproducibility for their tools.

bioinformatics↗

bioRxiv2023

Neuroprotective Effects of Naltrexone in a Mouse Model of Post-Traumatic Epilepsy

Traumatic Brain Injury (TBI) induces neuroinflammatory responses that can initiate epileptogenesis, which develops into epilepsy. Recently, we identified the anti-convulsive effects of naltrexone, a mu-opioid receptor (MOR) antagonist. While blocking opioid receptors can reduce inflammation, it is unclear if post-TBI epileptogenesis can be prevented by blocking MORs. Here, we tested if naltrexone prevents neuroinflammation and epileptogenesis post-TBI. TBI was induced by a modified Marmarau Weight-Drop (WD) method applied to four-week-old C57BL/6J male mice. Mice were given the pro-convulsant pentylenetetrazol (PTZ) on day two post-injury while telemetry-monitored mice received PTZ on day five. Naltrexone/vehicle treatment started two hours after PTZ. Integrated EEG-video (vEEG) recorded interictal events and spontaneous seizures for three months. Molecular, histological and neuroimaging techniques were used to evaluate neuroinflammation and neurodegeneration both acutely and chronically. Peripheral immune responses were assessed through serum chemokine/cytokine measurements. We observed increases in MOR expression, nitro-oxidative stress, mRNA expression of inflammatory cytokines, microgliosis, neurodegeneration, and white matter damage in the neocortex of TBI mice. vEEG revealed increased interictal events in TBI mice, with 71% developing epilepsy. Naltrexone ameliorated neuroinflammation and neurodegeneration, reduced interictal events and prevented epilepsy, illustrating that naltrexone is a promising drug to prevent TBI-associated neuroinflammation and epileptogenesis in post-traumatic epilepsy.

neuroscience↗

bioRxiv2023

Hyperexcitability and translational phenotypes in a preclinical model of SYNGAP1 mutations

SYNGAP1 is a critical gene for neuronal development, synaptic structure, and function. Although rare, the disruption of SYNGAP1 directly causes a genetically identifiable neurodevelopmental disorder (NDD) called SYNGAP1-related intellectual disability. Without functional SynGAP1 protein, patients present with intellectual disability, motor impairments, and epilepsy. Previous work using mouse models with a variety of germline and conditional mutations has helped delineate SynGAP1s critical roles in neuronal structure and function, as well as key biochemical signaling pathways essential to synapse integrity. Homozygous loss of SYNGAP1 is embryonically lethal. Heterozygous mutations of SynGAP1 result in a broad range of phenotypes including increased locomotor activity, impaired working spatial memory, impaired cued fear memory, and increased stereotypic behavior. Our in vivo functional data, using the original germline mutation mouse line from the Huganir laboratory, corroborated robust hyperactivity and learning and memory deficits. Here, we describe impairments in the translational biomarker domain of sleep, characterized using neurophysiological data collected with wireless telemetric electroencephalography (EEG). We discovered Syngap1+/- mice exhibited elevated spike trains in both number and duration, in addition to elevated power, most notably in the delta power band. Primary neurons from Syngap1+/- mice displayed increased network firing activity, greater spikes per burst, and shorter inter-burst intervals between peaks using high density micro-electrode arrays (HD-MEA). This work is translational, innovative, and highly significant as it outlines functional impairments in Syngap1 mutant mice. Simultaneously, the work utilized untethered, wireless neurophysiology that can discover potential biomarkers of Syngap1R-ID, for clinical trials, as it has done with other NDDs. Our work is substantial forward progress toward translational work for SynGAP1R-ID as it bridges in-vitro electrophysiological neuronal activity and function with in vivo neurophysiological brain activity and function. These data elucidate multiple quantitative, translational biomarkers in vivo and in vitro for the development of treatments for SYNGAP1-related intellectual disability.

neuroscience↗

bioRxiv2022

Clonal dynamics of SARS-CoV-2-specific T cells in children and adults with COVID-19

Children infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) develop less severe coronavirus disease 2019 (COVID-19) than adults. The mechanisms for the age-specific differences and the implications for infection-induced immunity are beginning to be uncovered. We show by longitudinal multimodal analysis that SARS-CoV-2 leaves a small footprint in the circulating T cell compartment in children with mild/asymptomatic COVID-19 compared to adult household contacts with the same disease severity who had more evidence of systemic T cell interferon activation, cytotoxicity and exhaustion. Children harbored diverse polyclonal SARS-CoV- 2-specific naive T cells whereas adults harbored clonally expanded SARS-CoV-2-specific memory T cells. More naive interferon-activated CD4+ T cells were recruited into the memory compartment and recovery was associated with the development of robust CD4+ memory T cell responses in adults but not children. These data suggest that rapid clearance of SARS-CoV-2 in children may compromise their cellular immunity and ability to resist reinfection. HIGHLIGHTSO_LIChildren have diverse polyclonal SARS-CoV-2-specific naive T cells C_LIO_LIAdults have clonally expanded exhausted SARS-CoV-2-specific memory T cells C_LIO_LIInterferon-activated naive T cells differentiate into memory T cells in adults but not children C_LIO_LIAdults but not children develop robust memory T cell responses to SARS-CoV-2 C_LI O_FIG O_LINKSMALLFIG WIDTH=177 HEIGHT=200 SRC="FIGDIR/small/478400v1_ufig1.gif" ALT="Figure 1"> View larger version (44K): org.highwire.dtl.DTLVardef@e9586org.highwire.dtl.DTLVardef@17aaf37org.highwire.dtl.DTLVardef@18575e0org.highwire.dtl.DTLVardef@fde4ae_HPS_FORMAT_FIGEXP M_FIG C_FIG

immunology↗

bioRxiv2020

Respiratory tract explant infection dynamics of influenza A virus in California sea lions, northern elephant seals, and rhesus macaques and severe acute respiratory syndrome virus-2 in rhesus macaques

To understand susceptibility of wild California sea lions and Northern elephant seals to influenza A virus (IAV), we developed an ex vivo respiratory explant model and used it to compare infection kinetics for multiple IAV subtypes. We first established the approach using explants from colonized rhesus macaques, a model for human IAV. Trachea, bronchi, and lungs from 11 California sea lions, 2 Northern elephant seals and 10 rhesus macaques were inoculated within 24 hours post-mortem with 6 strains representing 4 IAV subtypes. Explants from the 3 species showed similar IAV infection kinetics with peak viral titers 48-72 hours post-inoculation that increased by 2-4 log10 plaque forming units (PFU)/explant relative to the inoculum. Immunohistochemistry localized IAV infection to apical epithelial cells. These results demonstrate that respiratory tissue explants from wild marine mammals support IAV infection. In the absence of the ability to perform experimental infections of marine mammals, this ex vivo culture of respiratory tissues mirrors the in vivo environment and serves as a tool to study IAV susceptibility, host-range, and tissue tropism. ImportanceAlthough influenza A virus can infect marine mammals, a dearth of marine mammal cell lines and ethical and logistical challenges prohibiting experimental infections of living marine mammals means that little is known about IAV infection kinetics in these species. We circumvented these limitations by adapting a respiratory tract explant model first to establish the approach with rhesus macaques and then for use with explants from wild marine mammals euthanized for non-respiratory medical conditions. We observed that multiple strains representing 4 IAV subtypes infected trachea, bronchi, and lungs of macaques and marine mammals with variable peak titers and kinetics. This ex vivo model can define infection dynamics for IAV in marine mammals. Further, use of explants from animals euthanized for other reasons reduces use of animals in research.

microbiology↗