Abstract
Disruption of host cell barriers is a fundamental strategy enabling pathogens to establish a paracellular infection. Here, using dual RNA-Seq, we determine the in vivo host-pathogen transcriptomic landscape upon infection by the extracellular pathogen Leptospira interrogans and uncover a mechanism of cell–cell junction disruption. We demonstrate that, upon infection, an increase in intracellular calcium triggers tight junction destabilization, by activating the calmodulin and myosin light chain kinase signalization. We identify two bacterial effectors of the Virulence-Modifying (VM) proteins family, structurally related to toxin-like proteins, that promote modulation of calcium homeostasis and disruption of cell–cell junctions, thereby allowing Leptospira translocation across epithelium barriers, tissue colonization and pathogenicity. Furthermore, we demonstrate that at least one of these VM proteins is secreted and associates with host cells. Altogether, these findings reveal a unique strategy by which an extracellular pathogen secretes toxin-like proteins to exploit host calcium signaling for breaching epithelial barriers.
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Data availability
The raw fastq files of dual RNA-sequencing have been deposited in NCBI’s Gene Expression Omnibus (GEO, https://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE295802) and are accessible through GEO Series accession number GSE295802. The data are publicly available without restrictions. Source data are provided with this paper.
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Acknowledgements
This work has received financial support by the PTR (Programmes Transversaux de Recherche) grant (PTR2019-310) from Institut Pasteur Paris (to N.B.), by a Groot-23 from the department of Microbiology of Institut Pasteur Paris (to A.G.-G.), and by the National Institutes of Health grant P01 AI 168148 (to M.P. and N.B.). We thank the Ultrastructural BioImaging Platform (UTechS UBI, Institut Pasteur Paris) for technical support. We also acknowledge L. Lemée and R. Ouazahrou from Biomics Platform, C2RT, Institut Pasteur, Paris, France, supported by France Génomique (ANR-10-INBS-09) and IBISA for their technical help for RNASeq experiments. We are grateful to N. Sauvonnet, E. Lemichez, L. Tailleux, and M. Lago for critically reading the manuscript and helpful discussions. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
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N.B. and A.G.-G. conceptualized the study and designed the experiments. N.B. supervised the study. A.G.-G. conducted most of the experiments. G.H. prepared the samples for and performed the RNA sequencing. M.M. performed the analyses of the RNASeq data. M.P. performed gene inactivation and silencing. A.G.-G., G.H., M.M., M.P., and N.B. validated the data and analyses. N.B., M.P., A.G.-G., and M.M. participated in funding acquisition. A.G.-G. and N.B. wrote the original draft. All authors reviewed, edited and approved the final manuscript.
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Giraud-Gatineau, A., Haustant, G., Monot, M. et al. In vivo dual RNA-Seq uncovers key effectors of epithelial barrier disruption by an extracellular pathogen. Nat Commun (2026). https://doi.org/10.1038/s41467-026-69033-8
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DOI: https://doi.org/10.1038/s41467-026-69033-8
