Biology subjects

Coulpier, M.

Publications and source records attributed to Coulpier, M..

5 recordsLinked to original sources

bioRxiv2026

An RNA-centric interactomics screen identifies novel proviral and antiviral genome binding interactors for tick-borne encephalitis virus

The tick-borne encephalitis virus (TBEV), which belongs to the Orthoflavivirus genus, is a medically significant arbovirus in Europe and Asia. Despite distinct pathobiological outcomes, arboviruses have evolved specific strategies to co-opt cellular factors for replication and immune evasion, that involve both viral proteins and viral RNA. The RNA genome of TBEV, as both the substrate for genome replication and translation and a designated target for innate antiviral immunity, is a nexus for interactions with the proteome of host cells. Nonetheless, the molecular bases of these interactions and their implications for the replicative cycle of TBEV remain poorly understood. To create an inventory of such interactions and gain understanding of their functional import, we have resolved the set of cellular proteins bound to TBEV RNA in infected human cells using an agnostic RNA-centric approach. Functional annotation of the resulting core interactome of 215 human host factors showed that viral RNA is deeply embedded in multiple cellular pathways, including those related to RNA and protein metabolism, cytoskeletal scaffolding, vesicle trafficking and innate antiviral immunity. For selected human interactors, we addressed their impact on TBEV infection in gene knockdown experiments, thereby identifying multiple restriction and dependency factors. These included sensors and effectors of innate immune pathways, as well as epitranscriptomic modifiers. Among the former, the dynamin-like GTPase MX2 protein, an interferon-stimulated gene with antiviral activity against multiple viruses including mosquito-borne orthoflaviviruses, displayed unexpected proviral activity against TBEV and a second tick-borne orthoflavivirus. Among the latter, WDR4, the non-catalytic component of the METTL1-WDR4 methyltransferase complex, emerged as a restriction factor with broad-spectrum activity against arboviruses belonging to multiple families of positive-strand RNA viruses. In conclusion, this first description of the RNA interactome of a tick-borne orthoflavivirus illuminates the molecular interactions that underpin TBEV infection of human cells, which taken together reflect both the common ancestry of tick- and mosquito-borne orthoflaviviruses and their considerable evolutionary divergence.

molecular biology↗

bioRxiv2026

Characterization of emerging Oropouche virus tropism and pathogenicity.

BackgroundOropouche virus is an emerging arbovirus increasingly associated with neurological complications, but its human cellular tropism and potential routes to the central nervous system remain poorly defined. This study aimed to characterize infection across clinically relevant human cell types and to investigate interactions with a human blood-brain barrier model and human neuronal/glial cells. MethodsA panel of human cell lines and primary human cells relevant to systemic and neurological disease was infected with Oropouche virus. Viral replication and production of infectious particles were quantified using molecular assays and infectivity titrations, and viral protein expression was assessed by immunoblotting and immunofluorescence. Barrier crossing was evaluated using a Transwell brain endothelial model with permeability monitoring, and infection dynamics in neuronal/glial cultures derived from human neural progenitors were quantified by imaging-based analyses. Group comparisons used non-parametric tests with Dunn-Bonferroni correction and Mann-Whitney tests; neuronal/glial cell counts were analysed using linear models with Fisher tests for interaction terms and multiplicity-adjusted post hoc comparisons. ResultsOropouche virus productively infected hepatocyte-like and intestinal epithelial cells, with high viral RNA output and release of infectious progeny. Primary synoviocytes, chondrocytes and skeletal muscle cells were permissive but produced lower infectious titers. Brain endothelial cells were inoculated and virus was progressively detected in the basolateral compartment, while endothelial permeability remained unchanged, indicating barrier crossing without disruption. In neuronal/glial cultures, both neurons and astrocytes were susceptible; infection was associated with marked cytopathic changes and a preferential, accelerated decline in neuron abundance over time. ConclusionsThese findings demonstrate broad human cell tropism and support blood-brain barrier crossing without major loss of barrier integrity, alongside pronounced neuronal vulnerability. The described models provide a platform to dissect mechanisms of neuroinvasion and to evaluate targeted antiviral strategies.

microbiology↗

bioRxiv2025

Oropouche virus infects human neural progenitor cells and alters the growth of brain organoids

Oropouche virus (OROV), is the etiologic agent of Oropouche fever (OROF), an emerging zoonotic disease that has been prevalent in South and Central America since the 1960s. Starting late 2023, the current outbreak has raised concern about vertical transmission and potential adverse pregnancy outcomes. While serological evidences and recent studies support the vertical transmission of OROV, how infection affects the fetal brain remains unclear. Here we show that a strain of OROV, FG_2020, phylogenetically-related to the epidemic strain, efficiently and productively infects human neural progenitor cells and iPSC-derived brain organoids. The main phenotypic effect is proliferation arrest associated with apoptosis leading to the loss of neural rosette organization, a key signature of developing brain architecture. These data indicates that fetal brain is susceptible to OROV infection and that vertical transmission during the first months of pregnancy could lead to pathological effects on brain development.

microbiology↗

bioRxiv2022

Integrated protein-protein interaction and RNA interference screens reveal novel restriction and dependency factors for a tick-borne flavivirus in its human host

In Europe, tick-borne encephalitis virus (TBEV) is responsible for severe neurological disease in humans. Like other viruses, TBEV is an obligate intracellular life form whose survival requires subversion of metabolic processes and evasion of anti-viral pathways. This feat is achieved in no small part by binary interactions between dedicated viral proteins and host proteins. Such protein-protein interactions (PPI) constitute molecular determinants of critical pathobiologic traits of viruses, including host-range, zoonotic potential and virulence, and represent realistic targets for anti-viral therapies. To shed light on the pathobiology of TBEV in human, we have resolved the network of PPI established with its human host by interaction proteomics. A high-throughput screen for virus-host PPI was performed involving the complete set of open reading frames of TBEV and the cDNA libraries of Homo sapiens, by means of yeast two-hybrid methodology. We have discovered a large set of virus-host protein-protein interactions concerning 42 different human proteins directly interacting with nine viral proteins. Many of these human interactors have never been linked in the literature to viral infection. The functional significance of the host interactors in viral infection as viral dependency or restriction factors was then characterized in vitro by RNA interference, and their function inferred by bioinformatic analysis. Approximately 40% of the identified human proteins have a significative impact on TBEV viral replication. These are engaged in many biological processes, whose involvement in viral infection is expected for many, but enigmatic for some. Further work will be necessary to gain molecular understanding of how these biological processes support or restrict TBEV replication, and whether they constitute viral vulnerabilities that can be exploited therapeutically.

microbiology↗

bioRxiv2019

Pathological modeling of TBEV infection reveals differential innate immune responses in human neurons and astrocytes that correlate with their susceptibility to infection.

Tick-borne encephalitis virus (TBEV) is a member of the Flaviviridae family, Flavivirus genus, which includes several important human pathogens. It is responsible for neurological symptoms that may cause permanent disability or death, and, from a medical point of view, is the major arbovirus in Central/Northern Europe and North-eastern Asia. TBEV tropism is critical for neuropathogenesis, yet, little is known about the molecular mechanisms that govern the susceptibility of human brain cells to the virus. In this study, we sought to establish and characterize a new in vitro model of TBEV infection in the human brain and to decipher cell type-specific innate immunity and its relation to TBEV tropism and neuropathogenesis. We showed that infection of neuronal/glial cultures derived from human fetal neural progenitor cells (hNPCs) mimicked three major hallmarks of TBEV infection in the human brain, namely, preferential neuronal tropism, neuronal death and astrogliosis. We also showed that these cells had conserved their capacity to build an antiviral response against TBEV. TBEV-infected neuronal/glial cells, therefore, represented a highly relevant pathological model. By enriching the cultures in either human neurons or astrocytes, we further demonstrated qualitative and quantitative differential innate immune responses in the two cell types that correlated with their particular susceptibility to TBEV. Our results thus reveal that cell type-specific innate immunity is likely to contribute to shaping TBEV tropism for human brain cells. They offer a new in vitro model to further study TBEV-induced neuropathogenesis and improve our understanding of the mechanisms by which neurotropic viruses target and damage human brain cells.\n\nAuthor summaryTick-borne encephalitis virus (TBEV), a neurotropic Flavivirus that is responsible for encephalitis in humans, is of growing concern in Europe. Indeed, over the last two decades the number of reported cases has continuously increased and the virus has spread into new geographical areas. Whereas it is well established that neurons are the main target of TBEV in the human brain, the mechanisms that underlie this preferential tropism have not yet been elucidated. Here, we used neuronal/glial cells derived from human fetal neural progenitors to establish and characterize a new in vitro pathological model that mimics major hallmarks of TBEV infection in vivo; namely, neuronal tropism, neuronal death and astrogliosis. Using this highly relevant model, we showed that human neurons and astrocytes were both capable of developing an innate immune response against TBEV, but with dissimilar magnitudes that correlated with differential susceptibility to TBEV. Our results thus revealed that TBEV tropism for subsets of human brain cells is likely to depend on cell-type specific innate immunity. This improves our understanding of the mechanisms by which neurotropic viruses target and damage human brain cells and may help guide development of future therapies.

microbiology↗