Biology subjects

Legras, A.

Publications and source records attributed to Legras, A..

4 recordsLinked to original sources

bioRxiv2026

A rapid agarose-free protocol for preparing human organotypic lung cultures to study respiratory virus infection and evaluate antivirals ex vivo

We describe a standardized and reproducible procedure to generate human organotypic lung cultures from surgical lung resection for the study of respiratory infections. The protocol details tissue harvesting, biopsy punching, mechanical slicing, culture at the air-liquid interface. This technique enables robust ex vivo infections of human lung tissue with respiratory viruses, including Influenza A and Nipah. The described system can be used to study host-pathogen interactions, analyze innate immune responses, and evaluate antiviral candidates in physiologically relevant human lung tissue. For complete details on the use and execution of this protocol, please refer to Cezard et al1.

pathology↗

bioRxiv2025

Cis-aconitate therapy protects against influenza mortality by dual targeting of viral polymerase and ERK/AKT/NF-κB signaling

Influenza virus poses a significant global health challenge, causing approximately 500,000 deaths annually. Its ability to evade antiviral treatments and vaccine-induced immunity underscores the need for novel therapeutic approaches. Our study identifies cis-aconitate (cis-aco), a mitochondria-derived metabolite, as a potent dual-action agent against influenza, independently of its metabolic derivative, itaconate. Cis-aco impairs viral polymerase activity, suppressing viral mRNA expression and protein synthesis to inhibit replication across a range of influenza subtypes. This antiviral efficacy is confirmed in ex vivo human airway and lung organotypic models. Beyond its antiviral properties, cis-aco exhibits potent anti-inflammatory effects, disrupting key inflammatory cascades and reducing the secretion of inflammatory mediators. In a mouse model of influenza pneumonia, cis-aco mitigates viral replication, inflammation, and immune cell activation, significantly improving survival. Notably, its efficacy persists even when administered at later stages of infection, when oseltamivir/Tamiflu(R) is no longer effective. These findings position cis-aco as a promising influenza treatment, combining antiviral and anti-inflammatory benefits within a clinically relevant timeframe.

immunology↗

bioRxiv2024

From tissue to subcellular level : imaging human precision-cut lung slices (PCLS) to gain insight into pandemic bacterial or viral infections

We describe a method for the generation and deep imaging of human precision-cut lung slices (PCLS). PCLS bridge the gap between in vivo and in vitro studies, providing a robust system for visualizing events from tissue to subcellular levels in the three-dimensional lung environment, with the preservation of all resident cell types and cell-cell interactions. They also constitute a validated model for studying host cell-pathogen interactions. Here, we detail the generation of human PCLS, followed by their infection and imaging by laser scanning confocal microscopy and transmission electron microscopy (TEM). We establish the conditions for ex vivo infection and replication of two pathogens of relevance to human respiratory health: a virus (SARS-CoV-2) and a bacterium (Mycobacterium tuberculosis, Mtb). PCLS can be obtained in a single day, infected the next day, and were successfully cultivated for up to a week in this study. Imaging was performed on fixed samples. The preparation of PCLS took one day for confocal imaging and five days for TEM imaging. All procedures are readily adaptable to explore other pathogens and other species and are easy to implement by users with experience in tissue culture. Some specialist equipment (an Alabama tissue slicer) is required for PCLS generation.

cell biology↗

bioRxiv2021

Surfactin stimulated by pectin molecular patterns and root exudates acts as a key driver of Bacillus-plant mutualistic interaction

Bacillus velezensis is considered as model species belonging to the so-called B. subtilis complex that typically evolved to dwell in the soil rhizosphere niche and establish intimate association with plant roots. This bacterium provides protection to its natural host against diseases and represents one of the most promising biocontrol agents. However, the molecular basis of the cross-talk that this bacterium establishes with its natural host has been poorly investigated. We show here that these plant-associated bacteria have evolved some polymer-sensing system to perceive their host and that in response, they increase the production of the surfactin-type lipopeptide. Furthermore, we demonstrate that surfactin synthesis is favoured upon growth on root exudates and that this lipopeptide is a key component used by the bacterium to optimize biofilm formation, motility and early root colonization. In this specific nutritional context, the bacterium also modulates qualitatively the pattern of surfactin homologues co-produced in planta and mainly forms variants that are the most active at triggering plant immunity. Surfactin represents a shared good as it reinforces the defensive capacity of the host. ImportanceWithin the plant-associated microbiome, some bacterial species are of particular interest due to the disease protective effect they provide via direct pathogen suppression and/or stimulation of host immunity. While these biocontrol mechanisms are quite well characterized, we still poorly understand the molecular basis of the cross talk these beneficial bacteria initiate with their host. Here we show that the model species Bacillus velezensis stimulates production of the surfactin lipopeptide upon sensing pectin as cell surface molecular pattern and upon feeding on root exudates. Surfactin favors bacterial rhizosphere fitness on one hand and primes the plant immune system on the other hand. Our data therefore illustrate how both partners use this multifunctional compound as unique shared good to sustain mutualistic interaction.

microbiology↗