Dr Aurore Poirier


Research Fellow in Molecular Microbiology
PhD in Microbiology and Parasitology

Academic and research departments

School of Veterinary Medicine.

Biography

Areas of specialism

Microbiology; Molecular Biology; Biochemistry

University roles and responsibilities

  • Research fellow in Molecular Microbiology

My qualifications

2015
PhD in Microbiology and Parasitology
University of Montpellier
2012
MSc in Biology of Plants and Micro-organisms
University of Montpellier
2010
Bachelor degree in Biochemistry, Molecular and Cellular Biology and Genetics

University of Fundamental and Applied Sciences in Poitiers

Previous roles

01 March 2016 - 31 March 2018
Research Associate, working on the development of a bio-medical device to treat sepsis
University College London, Institute of Liver and Digestive Health

My publications

Publications

Poirier AC, Schmitt P, Rosa RD, Vanhove AS, Kieffer-Jaquinod S, Rubio TP, Charrière GM, Destoumieux-Garzón D (2014). Antimicrobial histones and DNA traps in invertebrate immunity: evidences in Crassostrea gigas.
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Although antimicrobial histones have been isolated from multiple metazoan species, their role in host defense has long remained unanswered. We found here that the hemocytes of the oyster Crassostrea gigas release antimicrobial H1-like and H5-like histones in response to tissue damage and infection. These antimicrobial histones were shown to be associated with extracellular DNA networks released by hemocytes, the circulating immune cells of invertebrates, in response to immune challenge. The hemocyte-released DNA was found to surround and entangle vibrios. This defense mechanism is reminiscent of the neutrophil extracellular traps (ETs) recently described in vertebrates. Importantly, oyster ETs were evidenced in vivo in hemocyte-infiltrated interstitial tissues surrounding wounds, whereas they were absent from tissues of unchallenged oysters. Consistently, antimicrobial histones were found to accumulate in oyster tissues following injury or infection with vibrios. Finally, oyster ET formation was highly dependent on the production of reactive oxygen species by hemocytes. This shows that ET formation relies on common cellular and molecular mechanisms from vertebrates to invertebrates. Altogether, our data reveal that ET formation is a defense mechanism triggered by infection and tissue damage, which is shared by relatively distant species suggesting either evolutionary conservation or convergent evolution within Bilateria.

KEYWORDS:

Bachère E, Rosa RD, Schmitt P, Poirier AC, Merou N, Charrière GM, Destoumieux-Garzón D. (2015). The new insights into the oyster antimicrobial defense: Cellular, molecular and genetic view.
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Oysters are sessile filter feeders that live in close association with abundant and diverse communities of microorganisms that form the oyster microbiota. In such an association, cellular and molecular mechanisms have evolved to maintain oyster homeostasis upon stressful conditions including infection and changing environments. We give here cellular and molecular insights into the Crassostrea gigas antimicrobial defense system with focus on antimicrobial peptides and proteins (AMPs). This review highlights the central role of the hemocytes in the modulation and control of oyster antimicrobial response. As vehicles for AMPs and other antimicrobial effectors, including reactive oxygen species (ROS), and together with epithelia, hemocytes provide the oyster with local defense reactions instead of systemic humoral ones. These reactions are largely based on phagocytosis but also, as recently described, on the extracellular release of antimicrobial histones (ETosis) which is triggered by ROS. Thus, ROS can signal danger and activate cellular responses in the oyster. From the current literature, AMP production/release could serve similar functions. We provide also new lights on the oyster genetic background that underlies a great diversity of AMP sequences but also an extraordinary individual polymorphism of AMP gene expression. We discuss here how this polymorphism could generate new immune functions, new pathogen resistances or support individual adaptation to environmental stresses.
Vanhove AS, Rubio TP, Nguyen AN, Lemire A, Roche D, Nicod J, Vergnes A, Poirier AC, Disconzi E, Bachère E, Le Roux F, Jacq A, Charrière GM, Destoumieux-Garzón D. (2016). Copper homeostasis at the host vibrio interface: lessons from intracellular vibrio transcriptomics.
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Recent studies revealed that several vibrio species have evolved the capacity to survive inside host cells. However, it is still often ignored if intracellular stages are required for pathogenicity. Virulence of Vibrio tasmaniensis LGP32, a strain pathogenic for Crassostrea gigas oysters, depends on entry into hemocytes, the oyster immune cells. We investigated here the mechanisms of LGP32 intracellular survival and their consequences on the host-pathogen interaction. Entry and survival inside hemocytes were required for LGP32-driven cytolysis of hemocytes, both in vivo and in vitro. LGP32 intracellular stages showed a profound boost in metabolic activity and a major transcription of antioxidant and copper detoxification genes, as revealed by RNA sequencing. LGP32 isogenic mutants showed that resistance to oxidative stress and copper efflux are two main functions required for vibrio intracellular stages and cytotoxicity to hemocytes. Copper efflux was also essential for host colonization and virulence in vivo. Altogether, our results identify copper resistance as a major mechanism to resist killing by phagocytes, induce cytolysis of immune cells and colonize oysters. Selection of such resistance traits could arise from vibrio interactions with copper-rich environmental niches including marine invertebrates, which favour the emergence of pathogenic vibrios resistant to intraphagosomal killing across animal species.
Barry Fuller, Jordi Gonzalez-Molina, Eloy Erro, Joana De Mendonca, Sheri Chalmers, Maooz Awan, Aurore Poirier, Clare Selden (2017). Applications and optimization of cryopreservation technologies to cellular therapeutics
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Delivery of cell therapies often requires the ability to hold products in readiness whilst logistical, regulatory and potency considerations are dealt with and recorded. This requires reversibly stopping biological time, a process which is often achieved by cryopreservation. However, cryopreservation itself poses many biological and biophysical challenges to living cells that need to be understood in order to apply the low temperature technologies to their best advantage. This review sets out the history of applied cryopreservation, our current understanding of the various processes involved in storage at cryogenic temperatures, and challenges for robust and reliable uses of cryopreservation within the cell therapy arena.
Robino E*, Poirier AC*, Amraoui H, Le Bissonnais S, Perret A, Lopez-Joven C, Auguet JC, Rubio TP, Cazevieille C, Rolland JL, Héchard Y, Destoumieux-Garzón D, Charrière GM (2019). Resistance of the oyster pathogen Vibrio tasmaniensis LGP32 against grazing by Vannella sp. marine amoeba involves Vsm and CopA virulence factors
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Vibrios are ubiquitous in marine environments and opportunistically colonize a broad range of hosts. Strains of present in oyster farms can thrive in oysters during juvenile mortality events and behave as facultative intracellular pathogen of oyster haemocytes. Herein, we wondered whether . LGP32 resistance to phagocytosis is specific to oyster immune cells or contributes to resistance to other phagocytes, like marine amoebae. To address this question, we developed an integrative study, from the first description of amoeba diversity in oyster farms to the characterization of LGP32 interactions with amoebae. An isolate of the genus, sp. AP1411, which was collected from oyster farms, is ubiquitous, and belongs to one clade of Vannella that could be found associated with . LGP32 was shown to be resistant to grazing by sp. AP1411 and this phenotype depends on some previously identified virulence factors: secreted metalloprotease Vsm and copper efflux p‐ATPase CopA, which act at different steps during amoeba–vibrio interactions, whereas some other virulence factors were not involved. Altogether, our work indicates that some virulence factors can be involved in multi‐host interactions of . ranging from protozoans to metazoans, potentially favouring their opportunistic behaviour.
Vibrio tasmaniensisVtasmaniensisVannellaVannellaVibrionaceaeVannellaVtasmaniensis
Rohaim, M.A.; Clayton, E.; Sahin, I.; Vilela, J.; Khalifa, M.E.; Al-Natour, M.Q.; Bayoumi, M.; Poirier, A.C.; Branavan, M.; Tharmakulasingam, M.; Chaudhry, N.S.; Sodi, R.; Brown, A.; Burkhart, P.; Hacking, W.; Botham, J.; Boyce, J.; Wilkinson, H.; William (2020). Artificial Intelligence-Assisted Loop Mediated Isothermal Amplification (ai-LAMP) for Rapid Detection of SARS-CoV-2.
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Until vaccines and effective therapeutics become available, the practical solution to transit safely out of the current coronavirus disease 19 (CoVID-19) lockdown may include the implementation of an effective testing, tracing and tracking system. However, this requires a reliable and clinically validated diagnostic platform for the sensitive and specific identification of SARS-CoV-2. Here, we report on the development of a de novo, high-resolution and comparative genomics guided reverse-transcribed loop-mediated isothermal amplification (LAMP) assay. To further enhance the assay performance and to remove any subjectivity associated with operator interpretation of results, we engineered a novel hand-held smart diagnostic device. The robust diagnostic device was further furnished with automated image acquisition and processing algorithms and the collated data was processed through artificial intelligence (AI) pipelines to further reduce the assay run time and the subjectivity of the colorimetric LAMP detection. This advanced AI algorithm-implemented LAMP (ai-LAMP) assay, targeting the RNA-dependent RNA polymerase gene, showed high analytical sensitivity and specificity for SARS-CoV-2. A total of ~200 coronavirus disease (CoVID-19)-suspected NHS patient samples were tested using the platform and it was shown to be reliable, highly specific and significantly more sensitive than the current gold standard qRT-PCR. Therefore, this system could provide an efficient and cost-effective platform to detect SARS-CoV-2 in resource-limited laboratories.