Biology subjects

Monteil, V.

Publications and source records attributed to Monteil, V..

10 recordsLinked to original sources

bioRxiv2026

Dual-Antigen CCHFV Vaccine Induces Neutralizing Immunity and Protection Against Lethal Challenge

Crimean-Congo hemorrhagic fever virus (CCHFV) is a WHO-priority pathogen with high mortality and wide global distribution. A major challenge in CCHFV vaccine development is identifying antigens that induce functional cellular and humoral immunity. We previously showed that the CCHF nucleoprotein (NP) elicits protective responses in mice and non-human primates but does not induce neutralizing antibodies. We therefore systematically screened six chimeric DNA vaccines expressing different CCHF glycoproteins combined with NP. A construct comprising the ectodomain of the glycoprotein Gc and NP elicited robust antibody and T-cell responses to both antigens. The Gc-NP gene was subsequently developed as a lipid nanoparticle-formulated mRNA vaccine using a scalable manufacturing pipeline. Gc-NP mRNA-LNP induced robust antigen-specific humoral and cellular responses comparable to those elicited by the corresponding DNA vaccine, despite the substantially lower dose. Both vaccine approaches generated Gc-directed neutralizing antibody responses against CCHFV pseudovirus and protected mice against homologous Hoti and heterologous IbAr10200 strain challenge. These findings demonstrate that systematic antigen screening combined with genetic vaccine platforms can identify a potent multi-antigen CCHF vaccine candidate.

immunology↗

bioRxiv2026

ISG15-USP18 signaling restrains viperin-dependent metabolic antiviral restriction

Type I interferon (IFN-I) responses are tightly regulated to balance antiviral defense with cellular homeostasis. In humans, interferon-stimulated gene 15 (ISG15) functions as a critical negative regulator of IFN-I signaling by stabilizing the IFN negative regulator USP18, yet the functional consequences of ISG15 deficiency remain elusive. Here, we show that the loss of ISG15 exaggerates the JAK-STAT activation and, downstream, amplifies multiple ISGs including the nucleotide-modifying enzyme RSAD2 (viperin). Our quantitative proteomics, genetic reconstitution, and signaling analyses establish that defective USP18 stabilization skews the IFN response towards viperin expression. This amplified ISG network promotes viperin-catalyzed accumulation of the antiviral nucleotide analog ddhCTP, resulting in enhanced inhibition of viral RNA synthesis and the replication of Crimean-Congo hemorrhagic fever virus and SARS-CoV-2. Together, these findings demonstrate an ISG15-USP18-viperin axis that can be targeted to boost the metabolic antiviral restriction.

microbiology↗

bioRxiv2026

Identification of MED13 and DDX60 as critical host factors for SARS-CoV-2 infections

The virus responsible for COVID-19, SARS-CoV-2, continues to spread through the world. The ongoing emergence of new variants with increased viral transmission and immune evasion continue to pose a challenge. Although large-scale genetic screens have identified numerous host factors required for SARS-CoV-2 infection, however the function of these hits remain incompletely understood. In this study, we performed a haploid forward genetic screen in chemically mutagenized mouse embryonic stem cells overexpressing human ACE2 and identified MED13 and DDX60 as important host factors involved in the modulation of SARS-CoV-2 infection. In this study, we have identified and characterized the function of these key element factors for SARS-CoV2 infection. Knockdown of CKM subunits--with the exception of CDK8--or the helicase DDX60 was sufficient to reduce SARS-CoV-2 infection across Vero E6, A549, and Calu-3 cells. During SARS-CoV-2 infection, MED13 was found to function downstream of the JAK/STAT interferon pathway, but also showed another function independently of the interferon response pathway. Surprisingly, while DDX60 is traditionally involved in the interferon response pathway, its knockdown reduces SARS-CoV-2 infection, suggesting DDX60 can promote SARS-CoV-2 infection Interestingly, while inactivation of MED13 or DDX60 markedly reduced SARS-CoV-2 and SARS-CoV infection, it did not affect MERS-CoV. Collectively, these results identify MED13 and DDX60 as critical host determinants for SARS-CoV-2 related-coronaviruses with pandemic potential. Impact statementUsing an unbiased haploid genetic screening approach, this study identifies for the first time MED13 and DDX60 as host factors that influence coronavirus replication through transcriptional and interferon-associated pathways. While DDX60 has previously been linked to antiviral signaling, our findings suggest it can promote coronavirus infection. Most interestingly, the effects of these factors extend beyond SARS-CoV-2 to other coronaviruses. These findings broaden the current understanding of coronavirus-host interaction by highlighting transcriptional control and interferon-associated pathways as modulators of infection rather than focusing solely on viral entry. The work provides mechanistic insight into how host regulatory networks influence coronavirus replication and suggests potential targets for host-directed therapies with activity against multiple present and future coronavirus threats. Data summaryThe authors confirm all supporting data, code and protocols have been provided within the article or through supplementary data files. RepositoriesThe data generated in this study are provided in the Supplementary Information/Source Data file. Sequencing data are available on NCBI Sequence Read Archive under the accession number BioProject PRJNA1271794. The next generation sequencing data generated in this study has been deposited in the NCBI Sequence Read Archive (SRA) under accession number SRX29485992, SRX29485993, SRX29485994, SRX29485995, SRX29485996, SRX29485997, SRX29485998, SRX29485999, SRX29486000, SRX29486001, SRX29486002, SRX29486003, SRX29486004, SRX29486005, SRX29486006, SRX29486007, SRX29486010, SRX29486011, SRX29486012, SRX29486013, SRX29486014, SRX29486015, SRX29486016, SRX29486017, SRX29486018, SRX29486019, SRX29486021, SRX29486022, SRX29486023, SRX29486024

microbiology↗

bioRxiv2024

Reconstructing bat antiviral immunity using epithelial organoids

Bats are remarkably resilient to viruses with pandemic potential. To resolve largely unknown molecular mechanisms governing their exceptional antiviral immunity, we established an organoid platform to model the entire respiratory airway and intestinal epithelium of the important viral reservoir species Rousettus aegyptiacus (Egyptian fruit bat). These bat organoids exhibit an unexpected diversity of cell types and support replication of highly pathogenic zoonotic viruses including Marburg virus (MARV) and MERS-Coronavirus. Following virus infection, bat organoids unleash a strong interferon response, uniquely regulated through virus-dependent and virus-independent mechanisms. By contrast, MARV infected human organoids fail to induce an antiviral gene response and express pro-inflammatory cytokines after interferon stimulation, revealing important molecular differences between bats and humans with implications for lethal Marburg virus infections in primates. These data provide the most comprehensive organoid platform in bats to decode species-specific differences and uncover fundamental principles of bat disease resilience to emerging viruses with pandemic potential.

immunology↗

bioRxiv2021

Clinical grade ACE2 effectively inhibits SARS-CoV-2 Omicron infections

The recent emergence of the SARS-CoV-2 variant Omicron has caused considerable concern due to reduced vaccine efficacy and escape from neutralizing antibody therapeutics. Omicron is spreading rapidly around the globe and is suspected to account for most new COVID-19 cases in several countries, though the severity of Omicron-mediated disease is still under debate. It is therefore paramount to identify therapeutic strategies that inhibit the Omicron SARS-CoV-2 variant. Here we report using 3D structural modelling that Spike of Omicron can still associate with human ACE2. Sera collected after the second mRNA-vaccination did not exhibit a protective effect against Omicron while strongly neutralizing infection of VeroE6 cells with the reference Wuhan strain, confirming recent data by other groups on limited vaccine and convalescent sera neutralization efficacy against Omicron. Importantly, clinical grade recombinant human soluble ACE2, a drug candidate currently in clinical development, potently neutralized Omicron infection of VeroE6 cells with markedly enhanced potency when compared to reference SARS-CoV-2 isolates. These data show that SARS-CoV-2 variant Omicron can be readily inhibited by soluble ACE2, providing proof of principle of a viable and effective therapeutic approach against Omicron infections.

molecular biology↗

bioRxiv2021

Clinical grade ACE2 as a universal agent to block SARS-CoV-2 variants

The recent emergence of multiple SARS-CoV-2 variants has caused considerable concern due to reduced vaccine efficacy and escape from neutralizing antibody therapeutics. It is therefore paramount to develop therapeutic strategies that inhibit all known and future SARS-CoV-2 variants. Here we report that all SARS-CoV-2 variants analyzed, including variants of concern (VOC) Alpha, Beta, Gamma, and Delta, exhibit enhanced binding affinity to clinical grade and phase 2 tested recombinant human soluble ACE2 (APN01). Importantly, soluble ACE2 neutralized infection of VeroE6 cells and human lung epithelial cells by multiple VOC strains with markedly enhanced potency when compared to reference SARS-CoV-2 isolates. Effective inhibition of infections with SARS-CoV-2 variants was validated and confirmed in two independent laboratories. These data show that SARS-CoV-2 variants that have emerged around the world, including current VOC and several variants of interest, can be inhibited by soluble ACE2, providing proof of principle of a pan-SARS-CoV-2 therapeutic.

molecular biology↗

bioRxiv2021

Structure-guided glyco-engineering of ACE2 for improved potency as soluble SARS-CoV-2 decoy receptor

Infection and viral entry of SARS-CoV-2 crucially depends on the binding of its Spike protein to angiotensin converting enzyme 2 (ACE2) presented on host cells. Glycosylation of both proteins is critical for this interaction. Recombinant soluble human ACE2 can neutralize SARS-CoV-2 and is currently undergoing clinical tests for the treatment of COVID-19. We used 3D structural models and molecular dynamics simulations to define the ACE2 N-glycans that critically influence Spike-ACE2 complex formation. Engineering of ACE2 N-glycosylation by site-directed mutagenesis or glycosidase treatment resulted in enhanced binding affinities and improved virus neutralization without notable deleterious effects on the structural stability and catalytic activity of the protein. Importantly, simultaneous removal of all accessible N-glycans from recombinant soluble human ACE2 yields a superior SARS-CoV-2 decoy receptor with promise as effective treatment for COVID-19 patients.

biochemistry↗

bioRxiv2021

A diabetic milieu increases cellular susceptibility to SARS-CoV-2 infections in engineered human kidney organoids and diabetic patients

SARS-CoV-2 infections lead to a high risk of hospitalization and mortality in diabetic patients. Why diabetic individuals are more prone to develop severe COVID-19 remains unclear. Here, we established a novel human kidney organoid model that mimics early hallmarks of diabetic nephropathy. High oscillatory glucose exposure resulted in metabolic changes, expansion of extracellular membrane components, gene expression changes determined by scRNAseq, and marked upregulation of angiotensin-converting enzyme 2 (ACE2). Upon SARS-CoV-2 infection, hyperglycemic conditions lead to markedly higher viral loads in kidney organoids compared to normoglycemia. Genetic deletion of ACE2, but not of the candidate receptor BSG/CD147, in kidney organoids demonstrated the essential role of ACE2 in SARS-CoV-2 infections and completely prevented SARS-CoV-2 infection in the diabetogenic microenvironment. These data introduce a novel organoid model for diabetic kidney disease and show that diabetic-induced ACE2 licenses the diabetic kidney to enhanced SARS-CoV-2 replication.

cell biology↗

bioRxiv2021

Identification of lectin receptors for conserved SARS-CoV-2 glycosylation sites

New SARS-CoV-2 variants are continuously emerging with critical implications for therapies or vaccinations. All 22 N-glycan sites of SARS-CoV-2 Spike remain highly conserved among the variants B.1.1.7, 501Y.V2 and P.1, opening an avenue for robust therapeutic intervention. Here we used a comprehensive library of mammalian carbohydrate-binding proteins (lectins) to probe critical sugar residues on the full-length trimeric Spike and the receptor binding domain (RBD) of SARS-CoV-2. Two lectins, Clec4g and CD209c, were identified to strongly bind to Spike. Clec4g and CD209c binding to Spike was dissected and visualized in real time and at single molecule resolution using atomic force microscopy. 3D modelling showed that both lectins can bind to a glycan within the RBD-ACE2 interface and thus interferes with Spike binding to cell surfaces. Importantly, Clec4g and CD209c significantly reduced SARS-CoV-2 infections. These data report the first extensive map and 3D structural modelling of lectin-Spike interactions and uncovers candidate receptors involved in Spike binding and SARS-CoV-2 infections. The capacity of CLEC4G and mCD209c lectins to block SARS-CoV-2 viral entry holds promise for pan-variant therapeutic interventions.

molecular biology↗

bioRxiv2020

Metabolic reprogramming and host-immune response against Crimean-Congo Hemorrhagic Fever Viruses

The pathogenesis and host-viral interactions of the Crimean-Congo hemorrhagic fever orthonairovirus (CCHFV) are convoluted and not well evaluated. Application of the multi-omics system biology approaches including biological network analysis in elucidating the complex host-viral response, allow for interrogating the viral pathogenesis. The present study aimed to fingerprint the system-level alterations during acute CCHFV-infection and the cellular immune responses during productive CCHFV-replication in vitro. We used system-wide network-based system biology analysis of peripheral blood mononuclear cells (PBMCs) from a longitudinal cohort of CCHF patients during the acute phase of infection and after one year of recovery (convalescent phase) and untargeted quantitative proteomics analysis of the most permissive CCHFV-infected Huh7 and SW13 cells. In the RNAseq analysis of the PBMCs, comparing the acute and convalescent-phase, we observed system-level hosts metabolic reprogramming towards central carbon and energy metabolism (CCEM) with distinct upregulation of oxidative phosphorylation (OXPHOS) during CCHFV-infection. Upon application of network-based system biology methods, negative coordination of the biological signaling systems like FOXO/Notch axis and Akt/mTOR/HIF-1 signaling with metabolic pathways during CCHFV-infection were observed. The temporal quantitative proteomics in Huh7 showed a dynamic change in the CCEM over time and was in agreement with the cross-sectional proteomics in SW13 cells. By blocking the two key CCEM pathways, glycolysis and glutaminolysis, viral replication was inhibited in vitro. Activation of key interferon stimulating genes during infection suggested the role of type I and II interferon-mediated antiviral mechanisms both at system-level and during progressive replication. Significance StatementA combination of multi-modal systems-wide host-immune response and in vitro temporal analysis identified molecular re-arrangement in CCEM and fingerprinting the interferon-mediated antiviral mechanism during CCHFV-infection. Using the newly gained insights, we then modulated the key pathways of CCEM by drugs and inhibited the productive CCHFV-replication in in vitro infection models. Our study thus provides a comprehensive, system-level picture of the regulation of cellular and metabolic pathways during productive CCHFV-infection for the first time that aids in identifying novel therapeutic targets and treatment strategies.

microbiology↗