Publications scientifiques de l'EnvA
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Milking mesenchymal stem cells: Updated protocols for cell lysate, secretome, and exosome extraction, and comparative analysis of their therapeutic potential
No full textInternational audienceThe potential of the cell lysate, secretome, and extracellular vesicles (EVs) of mesenchymal stem cells (MSCs) to modulate the immune response and promote tissue regeneration has positioned them as a promising option for cell-free therapy. Currently, many clinical trials in stem cells-derived EVs and secretome are in progress various diseases and sometimes the results are failing. The major challenge on this roadmap is the lack of a standard extraction method for exosome, secretome, and lysate. The most optimal method for obtaining the secretome of MSCs for clinical utilization involves a comprehensive approach that includes non-destructive collection methods, time optimization, multiple collection rounds, optimization of culture conditions, and quality control measures. Further research and clinical studies are warranted to validate and refine these methods for safe and effective utilization of the MSC exosome, secretome, and lysate in various clinical applications. To address these challenges, it is imperative to establish a standardized and unified methodology to ensure reliable evaluation of these extractions in clinical trials. This review seeks to outline the pros and cons of methods for the preparation of MSCsderived exosome, and secretome/lysate, and comparative analysis of their therapeutic potential
Network of ship movements and its potential in spreading pathogenic infectious salmon anemia virus among Norwegian fish farms
No full textInternational audienceIn Norway, infectious salmon anemia (ISA) is a notifiable and economically important disease. Accurately understanding between-farm transmission remains essential for ISA control and prevention. Using a network approach, our objective was to assess whether ship movements could potentially contribute to the transmission of pathogenic variants of ISA virus (ISAV-HPRΔ) between farms.We described yearly static ship contact (reconstructed according to delay between visits: Δ = 1, 8 and 15 days) and company affiliation networks. We assessed the relevance of salmon production areas as subdivisions of these networks. Finally, we identified ship movements that could have resulted in ISAV-HPRΔ transmission between confirmed ISA-HPRΔ cases and explored whether either network was associated with the spatiotemporal distribution of these cases using a permutation test.Connectivity was high in ship contact networks, with the largest strongly connected component encompassing ≥ 72 % of farms. Farms' affiliations and locations in the same or differing production areas influenced their likelihood of being connected, however increasing Δ enabled the connection of distant regions. Both networks were associated with the distribution of ISA cases.Ship movements and sharing of equipment or personnel are therefore potential viral transmission pathways. While the ship contact network was well structured by production areas, inadequate disinfection of ships could lead to longer ISAV survival times, thus resulting in long-distance ISAV-HPRΔ transmission events throughout the country. This study highlighted the need to further investigate the role of ships and fomites in fish disease spread; the use of genetic data could provide additional insights.</p
Anaplasma marginale modulates the microbiota of Rhipicephalus microplus organs involved in pathogen transmission
No full textInternational audienceThe cattle tick Rhipicephalus microplus is a vector for Anaplasma marginale in tropical and subtropical regions worldwide. The study of pathogen-microbiome-vector interactions at the tick organ scale is a promising area of development, unraveling control strategies for tick-borne diseases. Our study focused on how A. marginale infection affects the bacterial community within the salivary glands and ovaries of R. microplus. Engorged female ticks collected from cattle in a disease-endemic area of Argentina were further classified based on whether they were infected with A. marginale by targeting the msp1β gene through PCR diagnosis in tissue samples. We included negative control samples throughout the study. We analyzed the bacterial communities in tick tissues by sequencing the 16S rRNA V3-V4 region. Our results revealed significant differences in community composition between infected and uninfected samples. Sphingomonadaceae was identified as a predominant taxon in uninfected salivary glands and ovaries. Additionally, we constructed co-occurrence networks to study interactions within the microbial communities. It is noteworthy that A. marginale infection led to an increase in network complexity in the salivary glands, exerting the opposite effect on the ovaries. These findings reinforced the hypothesis that A. marginale impacts the microbiota of R. microplus at an organ-specific level
Diversity of the Ixodes ricinus Microbiome Across Belgian Ecoregions and Its Association with Pathogen and Symbiont Presence
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Molecular detection of Toxoplasma gondii in ready-to-eat salad mixes: multi-country survey using a validated and harmonised standard operating procedure, Europe, 2021 to 2022
No full textInternational audienceBackground Most Toxoplasma gondii infections in humans are considered foodborne, but the relative importance of the various routes of infection is largely unknown. Consumption of green produce contaminated with T. gondii oocysts has been identified as a possible source. Aim We aimed to estimate the occurrence and prevalence of T. gondii oocysts in commercially available ready-to-eat (RTE) salad mixes in 10 European countries. Methods A real-time PCR-based method for oocyst detection was developed and optimised by two laboratories and validated in an interlaboratory test. This detection method and a harmonised sampling strategy were applied in a multi-country study. Multivariable logistic regression was used to investigate risk factors for oocyst contamination of RTE salad. Results The real-time PCR method had a detection limit of 10 oocysts per 30 g of salad. We collected 3,329 RTE salad samples (baby leaf and cut leaf mixes) from October 2021 to September 2022. The prevalence of T. gondii oocyst contamination was 4.1% (95% confidence interval (CI): 3.4–4.8%; n = 3,293). In multivariable regression analysis, winter season, sampling and packaging of salad in Northern Europe and production of salad in Western Europe were associated with detection of T. gondii , with no statistically significant differences between salad types. Conclusion We estimated the prevalence of T. gondii oocysts in RTE leafy green salads using a validated and standardised procedure to assess the potential risk for human infection; highlighting the need to address this risk at each critical point of the salad production chain
Trichosporon asahii: A Potential Growth Promoter for C. gallinacea? Implications for Chlamydial Infections and Cell Culture
No full textInternational audienceThe cultivation of Chlamydia gallinacea, a recently identified species, is challenging due to the lack of an optimized protocol. In this study, several infection protocols were tested, including different cell lines, incubation temperatures, centrifugation methods and culture media. However, none were successful in field samples. The only exception was a chance co-culture with Trichosporon asahii, a microorganism commonly found in the chicken gut. This suggests that current in vitro methods may not be optimized for this species and that host-associated microorganisms may influence the in vivo growth of C. gallinacea, which is typically found in the chicken gut. These findings raise new questions and highlight the need for further investigation of microbial interactions within the host, particularly to understand their role in the proliferation of chlamydial species
Preconception carrier screening among assisted reproduction patients: insights from a monocentric survey in France
No full textInternational audienceResearch question: What are the opinions of individuals undergoing assisted reproductive technology in France on preconception genetic carrier screening for monogenic Mendelian diseases?Design: A prospective monocentric study using an anonymous online questionnaire to target patients who underwent a consultation at the Assisted Reproductive Technology (ART) service of the Obstetrics and Reproductive Medicine Department, Foch Hospital, between January 2021 and October 2023.Results: Of the 7793 patients successfully contacted by email, 1206 responded to the survey, yielding a 15.5% response rate. Most participants (90.8% [1091/1202]) agreed or strongly agreed that preconception genetic carrier screening represents a significant advancement in the field of assisted reproductive technology, 41.9% (501/1195) documented that such screening should be available to all couples planning to have children and 43.1% (515/1195) supported such screening being available to any adult wishing to know their carrier status.Conclusions: Support for preconception genetic carrier screening is strong among patients undergoing assisted reproduction. This patient population is ideal for initiating essential pilot studies in France concerning such screening. These studies are crucial for understanding and addressing economic and technological challenges, as well as advancing ethical considerations in this emerging field
Insight Into the Tick Neurosecretory System
No full textInternational audienceAlthough the nervous systems of ticks and insects are thought to have evolved convergently, the organization and functional architecture of the tick neurosecretory system, particularly the anatomical localization of neuropeptide release sites, remain largely uncharacterized. In the present study, we used immunohistochemical labeling with antibodies targeting various neuropeptide classes to identify previously unreported lateral and medial clusters of peptidergic neurosecretory cells (NSCs) within the anterior protocerebrum of the synganglion in Ixodes ricinus, the primary European vector of Lyme disease. These NSCs give rise to dense axonal projections forming a superficial network on the dorso-lateral synganglionic surface, in addition to extending neurites into nearly all internal lobes. Ultrastructural analyses via immunogold transmission electron microscopy demonstrated that axon terminals located on the synganglion surface terminate within the dorsal perineurium and secrete neuropeptides into an acellular neurilemma layer directly adjacent to the haemolymph compartment. Furthermore, both lateral and medial NSC terminals exhibited differential expression of muscarinic acetylcholine receptors (mAChRs), with type A and B subtypes detected, respectively, indicating cholinergic sensitivity. Physiological manipulation via microinjection of 100 nL of water into the haemocoel of unfed females resulted in a marked increase in neuropeptide-associated fluorescence at the terminal regions of dorsal surface axons, consistent with enhanced synthesis and axonal transport of neuropeptides. Conversely, administration of 10 µM acetylcholine (ACh) significantly attenuated the fluorescent signal, suggesting ACh-induced neuropeptide exocytosis. We propose that the observed fluorescence enhancement reflects neuropeptide accumulation in response to changes in haemolymph volume, whereas ACh-mediated signal reduction corresponds to stimulus-evoked hormonal release. Based on these findings, we propose a novel model in which acetylcholine functions as a hormonal trigger for peptide release from NSCs in ticks
Optimisation et validation d'une méthode combinant iDISCO et CUBIC pour étudier l'expression du gène précoce c-fos dans le cerveau de souris
No full textInternational audienceWhole-brain imaging following tissue clearing and immunolabeling as offers several advantages over traditional histological methods for revealing networks associated with c-Fos activation. Among the available techniques, iDISCO is considered one of the most effective for immunolabeling and has been widely adopted in recent years. However, the use of post-fixed brain samples remains challenging due to several limitations—most notably, tissue autofluorescence in microvessels and partial damage to the olfactory bulbs. In order to reveal neuronal network activated after odor exposure, we aimed to establish a tissue clearing method for post-fixed brain samples, to optimize it for studying neural networks of the olfactory system, and to set up an analysis pipeline
Comment notre vie prénatale influence-t-elle notre santé future ?
No full textInternational audienceLes expositions précoces à des facteurs de stress biologiques et/ou sociaux peuvent avoir un impact à long terme sur la santé des adultes. Les mécanismes biologiques qui sous-tendent ces origines développementales de la santé et de la maladie (DOHaD) ne sont pas entièrement compris. Les mécanismes épigénétiques gouvernent la détermination de l'identité cellulaire lors de la différenciation des organes au cours du développement embryonnaire. Cette plasticité développementale leur confère une sensibilité particulière à l'environnement. Ils constituent donc de bons candidats pour expliquer comment des événements précoces pourraient modifier durablement la physiologie et influencer le phénotype à l'âge adulte. Par ailleurs, les réponses des descendants diffèrent souvent selon le sexe. Au-delà d’un effet purement hormonal, l’aspect épigénétique sous-tend certainement en partie ces différences.Anne Gabory a abordé l'épigénétique sous l'aspect de l'empreinte parentale au cours de sa thèse avec Luisa Dandolo, puis s'est concentrée sur l'archivage de l'impact de l'environnement et son effet sur l'expression des gènes dans le cadre des Origines du Développement de la Santé et de la Maladie (DOHaD). Ses projets portent sur les effets épigénétiques de l'obésité maternelle avant et au cours de la gestation sur la santé de la descendance, en abordant trois aspects : les différences de réponse entre sexes, la possibilité de correction préconceptionnelle et l'exposition des individus à plusieurs stress de nature différente