Vincent Béringue

French National Institute for Agricultural Research, Lutetia Parisorum, Île-de-France, France

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Publications (75)326.39 Total impact

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    ABSTRACT: Guanabenz (GA) is an orally active α2-adrenergic agonist that has been used for many years for the treatment of hypertension. We recently described that GA is also active against both yeast and mammalian prions in an α2-adrenergic receptor-independent manner. These data suggest that this side-activity of GA could be explored for the treatment of prion-based diseases and other amyloid-based disorders. In this perspective, the potent antihypertensive activity of GA happens to be an annoying side-effect that could limit its use. In order to get rid of GA agonist activity at α2-adrenergic receptors, we performed a structure-activity relationship study around GA based on changes of the chlorine positions on the benzene moiety and then on the modifications of the guanidine group. Hence, we identified the two derivatives 6 and 7 that still possess a potent antiprion activity but were totally devoid of any agonist activity at α2-adrenergic receptors. Similarly to GA, 6 and 7 were also able to inhibit the protein folding activity of the ribosome (PFAR) which has been suggested to be involved in prion appearance/maintenance. Therefore, these two GA derivatives are worth being considered as drug candidates.
    ACS Chemical Neuroscience 09/2014; · 3.87 Impact Factor
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    ABSTRACT: The emergence of variant Creutzfeldt Jakob Disease (vCJD) is considered a likely consequence of human dietary exposure to Bovine Spongiform Encephalopathy (BSE) agent. More recently, secondary vCJD cases were identified in patients transfused with blood products prepared from apparently healthy donors who later went on to develop the disease. As there is no validated assay for detection of vCJD/BSE infected individuals the prevalence of the disease in the population remains uncertain. In that context, the risk of vCJD blood borne transmission is considered as a serious concern by health authorities. In this study, appropriate conditions and substrates for highly efficient and specific in vitro amplification of vCJD/BSE agent using Protein Misfolding Cyclic Amplification (PMCA) were first identified. This showed that whatever the origin (species) of the vCJD/BSE agent, the ovine Q171 PrP substrates provided the best amplification performances. These results indicate that the homology of PrP amino-acid sequence between the seed and the substrate is not the crucial determinant of the vCJD agent propagation in vitro. The ability of this method to detect endogenous vCJD/BSE agent in the blood was then defined. In both sheep and primate models of the disease, the assay enabled the identification of infected individuals in the early preclinical stage of the incubation period. Finally, sample panels that included buffy coat from vCJD affected patients and healthy controls were tested blind. The assay identified three out of the four tested vCJD affected patients and no false positive was observed in 141 healthy controls. The negative results observed in one of the tested vCJD cases concurs with results reported by others using a different vCJD agent blood detection assay and raises the question of the potential absence of prionemia in certain patients.
    PLoS Pathogens 06/2014; 10(6):e1004202. · 8.14 Impact Factor
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    ABSTRACT: The dietary exposure of the human population to the prions responsible for the bovine spongiform encephalopathy (BSE) epizooty has led to the emergence of variant Creutzfeldt-Jakob disease (vCJD). This fatal, untreatable neurodegenerative disorder is a growing public health concern because the prevalence of the infection seems much greater than the disease incidence and because secondary transmission of vCJD by blood transfusion or use of blood products has occurred. A current limitation in variant CJD risk assessment purposes is the lack of quantitative information on the infectivity of contaminated tissues. To these aims, we tested the potential of a transgenic mouse line overexpressing human PrP, which was previously reported to propagate vCJD prions. Endpoint titration of vCJD infectivity in different tissues was evaluated by two different methods: i) the "classical" bioassay, based on the appearance of clinical symptoms and the detection of pathological prion protein in tissues of the inoculated mouse, ii) a shortened bioassay based on the detection of the protein in the mouse spleen at defined time points. Both methods proved equally sensitive in quantifying infectivity, even after very low dose inoculation of infected material, but the time time-schedule was shortened from ∼2.5-year to ∼1-year with the spleen bioassay. Compared to the 'gold-standard' RIII model routinely used for endpoint titration of vCJD/BSE prions, either method improved the sensitivity by >2 orders of magnitude and allowed re-evaluating the infectious titre of spleen from a vCJD individual at disease end stage to >1000-fold higher values.
    Journal of virology. 05/2014;
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    ABSTRACT: Prion transmission can occur by blood transfusion in human variant Creutzfeldt-Jakob disease and in experimental animal models, including sheep. Screening of blood and its derivatives for the presence of prions became therefore a major public health issue. As infectious titer in blood is reportedly low, highly sensitive and robust methods are required to detect prions in blood and blood derived products. The objectives of this study were to compare different methods - in vitro, ex vivo and in vivo assays - to detect prion infectivity in cells prepared from blood samples obtained from scrapie infected sheep at different time points of the disease. Protein misfolding cyclic amplification (PMCA) and bioassays in transgenic mice expressing the ovine prion protein were the most efficient methods to identify infected animals at any time of the disease (asymptomatic to terminally-ill stages). However scrapie cell and cerebellar organotypic slice culture assays designed to replicate ovine prions in culture also allowed detection of prion infectivity in blood cells from asymptomatic sheep. These findings confirm that white blood cells are appropriate targets for preclinical detection and introduce ex vivo tools to detect blood infectivity during the asymptomatic stage of the disease.
    PLoS ONE 01/2014; 9(8):e104287. · 3.53 Impact Factor
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    ABSTRACT: The deletion of the cellular form of the prion protein (PrP(C)) in mouse, goat, and cattle has no drastic phenotypic consequence. This stands in apparent contradiction with PrP(C) quasi-ubiquitous expression and conserved primary and tertiary structures in mammals, and its pivotal role in neurodegenerative diseases such as prion and Alzheimer's diseases. In zebrafish embryos, depletion of PrP ortholog leads to a severe loss-of-function phenotype. This raises the question of a potential role of PrP(C) in the development of all vertebrates. This view is further supported by the early expression of the PrP(C) encoding gene (Prnp) in many tissues of the mouse embryo, the transient disruption of a broad number of cellular pathways in early Prnp(-/-) mouse embryos, and a growing body of evidence for PrP(C) involvement in the regulation of cell proliferation and differentiation in various types of mammalian stem cells and progenitors. Finally, several studies in both zebrafish embryos and in mammalian cells and tissues in formation support a role for PrP(C) in cell adhesion, extra-cellular matrix interactions and cytoskeleton. In this review, we summarize and compare the different models used to decipher PrP(C) functions at early developmental stages during embryo- and organo-genesis and discuss their relevance.
    Frontiers in Cell and Developmental Biology 01/2014; 2:58.
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    ABSTRACT: Based on its developmental pattern of expression, early studies suggested the implication of the mammalian Prion protein PrP, a glycosylphosphatidylinositol-anchored ubiquitously expressed and evolutionary conserved glycoprotein encoded by the Prnp gene, in early embryogenesis. However, gene invalidation in several species did not result in obvious developmental abnormalities and it was only recently that it was associated in mice with intra-uterine growth retardation and placental dysfunction. A proposed explanation for this lack of easily detectable developmental-related phenotype is the existence in the genome of one or more gene (s) able to compensate for the absence of PrP. Indeed, two other members of the Prnp gene family have been recently described, Doppel and Shadoo, and the consequences of their invalidation alongside that of PrP tested in mice. No embryonic defect was observed in mice depleted for Doppel and PrP. Interestingly, the co-invalidation of PrP and Shadoo in two independent studies led to apparently conflicting observations, with no apparent consequences in one report and the observation of a developmental defect of the ectoplacental cone that leads to early embryonic lethality in the other. This short review aims at summarizing these recent, apparently conflicting data highlighting the related biological questions and associated implications in terms of animal and human health.
    Frontiers in Cell and Developmental Biology 01/2014; 2:35.
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    ABSTRACT: Prions are proteinaceous infectious agents responsible for fatal neurodegenerative diseases in animals and humans. They are essentially composed of PrP(Sc), an aggregated, misfolded conformer of the ubiquitously expressed host-encoded prion protein (PrP(C)). Stable variations in PrP(Sc) conformation are assumed to encode the phenotypically tangible prion strains diversity. However the direct contribution of PrP(Sc) quaternary structure to the strain biological information remains mostly unknown. Applying a sedimentation velocity fractionation technique to a panel of ovine prion strains, classified as fast and slow according to their incubation time in ovine PrP transgenic mice, has previously led to the observation that the relationship between prion infectivity and PrP(Sc) quaternary structure was not univocal. For the fast strains specifically, infectivity sedimented slowly and segregated from the bulk of proteinase-K resistant PrP(Sc). To carefully separate the respective contributions of size and density to this hydrodynamic behavior, we performed sedimentation at the equilibrium and varied the solubilization conditions. The density profile of prion infectivity and proteinase-K resistant PrP(Sc) tended to overlap whatever the strain, fast or slow, leaving only size as the main responsible factor for the specific velocity properties of the fast strain most infectious component. We further show that this velocity-isolable population of discrete assemblies perfectly resists limited proteolysis and that its templating activity, as assessed by protein misfolding cyclic amplification outcompetes by several orders of magnitude that of the bulk of larger size PrP(Sc) aggregates. Together, the tight correlation between small size, conversion efficiency and duration of disease establishes PrP(Sc) quaternary structure as a determining factor of prion replication dynamics. For certain strains, a subset of PrP assemblies appears to be the best template for prion replication. This has important implications for fundamental studies on prions.
    PLoS Pathogens 10/2013; 9(10):e1003702. · 8.14 Impact Factor
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    ABSTRACT: In naturally acquired transmissible spongiform encephalopathies, the pathogenic agents or prions spread from the sites of initial peripheral uptake or replication to the brain where they cause progressive and fatal neurodegeneration. Routing via the peripheral nervous system is considered as one of the main pathways to attain the central nervous system. Replication of prions in Schwann cells is viewed as a potentially important parameter for efficient prion spread along nerves. Here we used a Cre-loxP mouse transgenetic approach to disrupt PrPC specifically in myelinating Schwann cells. Despite the use of infection routes targeting highly myelinated nerves, there was no alteration in mouse prion pathogenesis, suggesting that conversion-dependent, centripetal spread of prions does not crucially rely on PrPC expressed by myelinating Schwann cells.
    Journal of General Virology 02/2013; · 3.13 Impact Factor
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    ABSTRACT: Using a yeast-based assay, a previously unsuspected antiprion activity was found for imiquimod (IQ), a potent Toll-like receptor 7 (TLR7) agonist already used for clinical applications. The antiprion activity of IQ was first detected against yeast prions [PSI (+) ] and [URE3], and then against mammalian prion both ex vivo in a cell-based assay and in vivo in a transgenic mouse model for prion diseases. In order to facilitate structure-activity relationship studies, we conducted a new synthetic pathway which provides a more efficient means of producing new IQ chemical derivatives, the activity of which was tested against both yeast and mammalian prions. The comparable antiprion activity of IQ and its chemical derivatives in the above life forms further emphasizes the conservation of prion controlling mechanisms throughout evolution. Interestingly, this study also demonstrated that the antiprion activity of IQ and IQ-derived compounds is independent from their ability to stimulate TLRs. Furthermore, we found that IQ and its active chemical derivatives inhibit the protein folding activity of the ribosome (PFAR) in vitro.
    PLoS ONE 01/2013; 8(8):e72112. · 3.53 Impact Factor
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    ABSTRACT: ABSTRACT Measurements of the presence of prions in biological tissues or fluids rely more and more on cell-free assays. Although protein misfolding cyclic amplification (PMCA) has emerged as a valuable, sensitive tool, it is currently hampered by its lack of robustness and rapidity for high-throughput purposes. Here, we made a number of improvements making it possible to amplify the maximum levels of scrapie prions in a single 48-h round and in a microplate format. The amplification rates and the infectious titer of the PMCA-formed prions appeared similar to those derived from the in vivo laboratory bioassays. This enhanced technique also amplified efficiently prions from different species, including those responsible for human variant Creutzfeldt-Jakob disease. This new format should help in developing ultrasensitive, high-throughput prion assays for cognitive, diagnostic, and therapeutic applications. IMPORTANCE The method developed here allows large-scale, fast, and reliable cell-free amplification of subinfectious levels of prions from different species. The sensitivity and rapidity achieved approach or equal those of other recently developed prion-seeded conversion assays. Our simplified assay may be amenable to high-throughput, automated purposes and serve in a complementary manner with other recently developed assays for urgently needed antemortem diagnostic tests, by using bodily fluids containing small amounts of prion infectivity. Such a combination of assays is of paramount importance to reduce the transfusion risk in the human population and to identify asymptomatic carriers of variant Creutzfeldt-Jakob disease.
    mBio 01/2013; 5(1). · 6.88 Impact Factor
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    ABSTRACT: Variant Creutzfeldt-Jakob disease (vCJD) is a neurodegenerative infectious disorder, characterized by a prominent accumulation of pathological isoforms of the prion protein (PrP(TSE)) in the brain and lymphoid tissues. Since the publication in the United Kingdom of four apparent vCJD cases following transfusion of red blood cells and one apparent case following treatment with factor VIII, the presence of vCJD infectivity in the blood seems highly probable. For effective blood testing of vCJD individuals in the preclinical or clinical phase of infection, it is considered necessary that assays detect PrP(TSE) concentrations in the femtomolar range. We have developed a three-step assay that firstly captures PrP(TSE) from infected blood using a plasminogen-coated magnetic-nanobead method prior to its serial amplification via protein misfolding cyclic amplification (PMCA) and specific PrP(TSE) detection by western blot. We achieved a PrP(TSE) capture yield of 95% from scrapie-infected material. We demonstrated the possibility of detecting PrP(TSE) in white blood cells, in buffy coat and in plasma isolated from the blood of scrapie-infected sheep collected at the pre-clinical stage of the disease. The test also allowed the detection of PrP(TSE) in human plasma spiked with a 10(-8) dilution of vCJD-infected brain homogenate corresponding to the level of sensitivity (femtogram) required for the detection of the PrP(TSE) in asymptomatic carriers. The 100% specificity of the test was revealed using a blinded panel comprising 96 human plasma samples. We have developed a sensitive and specific amplification assay allowing the detection of PrP(TSE) in the plasma and buffy coat fractions of blood collected at the pre-clinical phase of the disease. This assay represents a good candidate as a confirmatory assay for the presence of PrP(TSE) in blood of patients displaying positivity in large scale screening tests.
    PLoS ONE 01/2013; 8(7):e69632. · 3.53 Impact Factor
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    ABSTRACT: The emergence of variant Creutzfeldt Jakob Disease (vCJD) is considered a likely consequence of human dietary exposure to Bovine Spongiform Encephalopathy (BSE) agent. More recently, secondary vCJD cases were identified in patients transfused with blood products prepared from apparently healthy donors who later went on to develop the disease. As there is no validated assay for detection of vCJD/BSE infected individuals the prevalence of the disease in the population remains uncertain. In that context the risk of vCJD blood borne transmission is considered as a serious concern by health authorities. In this study, appropriate conditions and substrates for highly efficient and specific in vitro amplification of vCJD/BSE agent using Protein Misfolding Cyclic Assay (PMCA) were first identified. This showed that whatever the origin (species) of vCJD/BSE agent, the ovine Q171 PrP substrates provided the best amplification performances. These results indicate that the homology of PrP amino-acid sequence between the seed and the substrate is not the crucial determinant of the vCJD agent in vitro propagation. The ability of this method to detect endogenous vCJD/BSE agent in the blood was then defined. In both sheep and primate models of the disease, the assay enabled the identification of infected individuals in the early preclinical stage of the incubation period. Finally, blood from two vCJD affected patients and 135 healthy controls were tested. The assay detected the presence of the vCJD case within a pool of several dozens of human blood samples. The equivalent 0.05 μL of whole blood from the vCJD affected patient was sufficient for amplifying PrPres.These results open new possibilities for vCJD screening and prevention of its iatrogenic transmission
    Prion 01/2013; 7:14-15. · 2.13 Impact Factor
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    ABSTRACT: Upon prion infection, abnormal prion protein (PrP (Sc) ) self-perpetuate by conformational conversion of α-helix-rich PrP (C) into β sheet enriched form, leading to formation and deposition of PrP (Sc) aggregates in affected brains. However the process remains poorly understood at the molecular level and the regions of PrP critical for conversion are still debated. Minimal amino acid substitutions can impair prion replication at many places in PrP. Conversely, we recently showed that bona fide prions could be generated after introduction of eight and up to 16 additional amino acids in the H2-H3 inter-helix loop of PrP. Prion replication also accommodated the insertions of an octapeptide at different places in the last turns of H2. This reverse genetic approach reveals an unexpected tolerance of prions to substantial sequence changes in the protease-resistant part which is associated with infectivity. It also demonstrates that conversion does not require the presence of a specific sequence in the middle of the H2-H3 area. We discuss the implications of our findings according to different structural models proposed for PrP (Sc) and questioned the postulated existence of an N- or C-terminal prion domain in the protease-resistant region.
    Prion 12/2012; 7(2). · 2.13 Impact Factor
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    ABSTRACT: Although the pivotal implication of the host-encoded Prion protein, PrP, in the neuropathology of transmissible spongiform encephalopathy is known for decades, its biological role remains mostly elusive. Genetic inactivation is one way to assess such issue but, so far, PrP-knockout mice did not help much. However, recent reports involving (1) further studies of these mice during embryogenesis, (2) knockdown experiments in Zebrafish and (3) knockdown of Shadoo, a protein with PrP-like functional domains, in PrP-knockout mice, all suggested a role of the Prion protein family in early embryogenesis. This view is challenged by the recent report that PrP/Shadoo knockout mice are healthy and fertile. Although puzzling, these apparently contradictory data may on the contrary help at deciphering the Prion protein family role through focusing scientific attention outside the central nervous system and by helping the identification of other loci involved in the genetic robustness associated with PrP.
    Prion 11/2012; 7(2). · 2.13 Impact Factor
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    ABSTRACT: Prions cause fatal neurodegenerative conditions and result from the conversion of host-encoded cellular prion protein (PrP(C)) into abnormally folded scrapie PrP (PrP(Sc)). Prions can propagate both in neurons and astrocytes, yet neurotoxicity mechanisms remain unclear. Recently, PrP(C) was proposed to mediate neurotoxic signaling of β-sheet-rich PrP and non-PrP conformers independently of conversion. To investigate the role of astrocytes and neuronal PrP(C) in prion-induced neurodegeneration, we set up neuron and astrocyte primary cocultures derived from PrP transgenic mice. In this system, prion-infected astrocytes delivered ovine PrP(Sc) to neurons lacking PrP(C) (prion-resistant), or expressing a PrP(C) convertible (sheep) or not (mouse, human). We show that interaction between neuronal PrP(C) and exogenous PrP(Sc) was not sufficient to induce neuronal death but that efficient PrP(C) conversion was required for prion-associated neurotoxicity. Prion-infected astrocytes markedly accelerated neurodegeneration in homologous cocultures compared to infected single neuronal cultures, despite no detectable neurotoxin release. Finally, PrP(Sc) accumulation in neurons led to neuritic damages and cell death, both potentiated by glutamate and reactive oxygen species. Thus, conversion of neuronal PrP(C) rather than PrP(C)-mediated neurotoxic signaling appears as the main culprit in prion-induced neurodegeneration. We suggest that active prion replication in neurons sensitizes them to environmental stress regulated by neighboring cells, including astrocytes.
    The FASEB Journal 06/2012; 26(9):3854-61. · 5.70 Impact Factor
  • Vincent Béringue, Jean-Luc Vilotte, Hubert Laude
    Medecine sciences: M/S 06/2012; 28(6-7):565-8. · 0.56 Impact Factor

Publication Stats

2k Citations
326.39 Total Impact Points

Institutions

  • 2003–2014
    • French National Institute for Agricultural Research
      • Virologie et Immunologie Moléculaires (VIM)
      Lutetia Parisorum, Île-de-France, France
  • 2006
    • Station Biologique de Roscoff
      Rosko, Brittany, France
  • 2003–2004
    • Imperial College London
      • Faculty of Medicine
      London, ENG, United Kingdom
  • 1997–2002
    • Cea Leti
      Grenoble, Rhône-Alpes, France
    • Atomic Energy and Alternative Energies Commission
      Fontenay, Île-de-France, France
  • 2000
    • National Institute of Allergy and Infectious Diseases
      Maryland, United States
  • 1998
    • National Institutes of Health
      Maryland, United States