Carole Crozet
Centre national de la recherche scientifique
Network
Latest external collaboration on country level. Dive into details by clicking on the dots.
Publication
Featured researches published by Carole Crozet.
Journal of Neurochemistry | 2004
Véronique Perrier; Jérôme Solassol; Carole Crozet; Yveline Frobert; Chantal Mourton-Gilles; Jacques Grassi; Sylvain Lehmann
The use of anti‐PrP antibodies represents one of the most promising strategies for the treatment of prion diseases. In the present study, we screened various anti‐PrP antibodies with the aim of identifying those that would block PrPSc replication in prion‐infected cell culture. Two antibodies, SAF34 recognizing the flexible octarepeats region on HuPrP protein, and SAF61 directed against PrP amino acid residues (144–152), not only inhibited PrPSc formation in prion‐infected neuroblastoma cells but also decreased the PrPC levels in non‐infected N2a cells. In addition, treatment with both SAF34 and SAF61 antibodies decreased PrPC and PrPSc levels in the cells synergistically. In the presence of both antibodies, our results showed that the mode of action which leads to the disappearance of PrPSc in cells is directly coupled to PrPC degradation by reducing the half‐life of the PrPC protein.
Proteomics | 2009
Stéphane Roche; Bruno Delorme; Robert A.J. Oostendorp; Romain Barbet; David Caton; Danièle Noël; Karim Boumediene; Helen A. Papadaki; Béatrice Cousin; Carole Crozet; Ollivier Milhavet; Louis Casteilla; Jacques Hatzfeld; Christian Jorgensen; Pierre Charbord; Sylvain Lehmann
Mesenchymal stem cells (MSC) are adult multipotential progenitors which have a high potential in regenerative medicine. They can be isolated from different tissues throughout the body and their homogeneity in terms of phenotype and differentiation capacities is a real concern. To address this issue, we conducted a 2‐DE gel analysis of mesenchymal stem cells isolated from bone marrow (BM), adipose tissue, synovial membrane and umbilical vein wall. We confirmed that BM and adipose tissue derived cells were very similar, which argue for their interchangeable use for cell therapy. We also compared human mesenchymal to embryonic stem cells and showed that umbilical vein wall stem cells, a neo‐natal cell type, were closer to BM cells than to embryonic stem cells. Based on these proteomic data, we could propose a panel of proteins which were the basis for the definition of a mesenchymal stem cell proteomic signature.
Journal of Cell Science | 2004
Alain Mangé; Carole Crozet; Sylvain Lehmann; Florence Béranger
Prion diseases are fatal transmissible neurodegenerative disorders characterized by the accumulation of an abnormally folded isoform of the cellular prion protein (PrPC) denoted PrPSc. Recently, wild-type and pathogenic PrP mutants have been shown to be degraded by the endoplasmic reticulum-associated degradation proteasome pathway after translocation into the cytosol. We show here that a protease resistant form of PrP accumulated in the nuclei of prion-infected cells independently of proteasome activity, and that this nuclear translocation required an intact microtubule network. Moreover, our results show for the first time that nuclear PrP interacts with chromatin in vivo, which may have physiopathological consequences in prion diseases
Biochemical and Biophysical Research Communications | 2008
Florence Béranger; Carole Crozet; Andrew Goldsborough; Sylvain Lehmann
Neurodegenerative disorders such as Alzheimers, Huntingtons, and prion diseases are characterized by abnormal protein deposits in the brain of affected patients. In prion diseases, a key event in the pathogenesis is the conversion of the normal prion protein (PrP(c)) into abnormal protease resistant PrP(Sc) deposits, a phenomenon associated with a higher sensitivity to oxidative stress in vitro. In cellular models of Alzheimer and Huntington diseases, the disaccharide trehalose has been shown to be effective in inhibiting huntingtin and Abeta peptide aggregates and reducing their associated toxicity. We show in this study that trehalose treatment of prion-infected cells decreases the size of de novo produced PrP(Sc) aggregates and modify their subcellular localization. Despite the fact that trehalose does not modify the protease resistance properties of PrP(Sc) molecules, it significantly protects prion-infected cells from induced oxidative damage, suggesting that this compound is of therapeutic interest.
Journal of Virology | 2004
Thierry Baron; Carole Crozet; Anne-Gaëlle Biacabe; Sandrine Philippe; Jérémie Verchere; Anna Bencsik; Jean-Yves Madec; Didier Calavas; Jacques Samarut
ABSTRACT The existence of different strains of infectious agents involved in scrapie, a transmissible spongiform encephalopathy (TSE) of sheep and goats, remains poorly explained. These strains can, however, be differentiated by characteristics of the disease in mice and also by the molecular features of the protease-resistant prion protein (PrPres) that accumulates into the infected tissues. For further analysis, we first transmitted the disease from brain samples of TSE-infected sheep to ovine transgenic [Tg(OvPrP4)] and to wild-type (C57BL/6) mice. We show that, as in sheep, molecular differences of PrPres detected by Western blotting can differentiate, in both ovine transgenic and wild-type mice, infection by the bovine spongiform encephalopathy (BSE) agent from most scrapie sources. Similarities of an experimental scrapie isolate (CH1641) with BSE were also likewise found following transmission in ovine transgenic mice. Secondly, we transmitted the disease to ovine transgenic mice by inoculation of brain samples of wild-type mice infected with different experimental scrapie strains (C506M3, 87V, 79A, and Chandler) or with BSE. Features of these strains in ovine transgenic mice were reminiscent of those previously described for wild-type mice, by both ratios and by molecular masses of the different PrPres glycoforms. Moreover, these studies revealed the diversity of scrapie strains and their differences with BSE according to labeling by a monoclonal antibody (P4). These data, in an experimental model expressing the prion protein of the host of natural scrapie, further suggest a genuine diversity of TSE infectious agents and emphasize its linkage to the molecular features of the abnormal prion protein.
EMBO Reports | 2001
Carole Crozet; Anna Bencsik; Frédéric Flamant; Jacques Samarut; Thierry Baron
The occurrence of the variant Creutzfeldt–Jakob disease (vCJD), related to bovine spongiform encephalopathy (BSE), raises the important question of the sources of human contamination. The possibility that sheep may have been fed with BSE‐contaminated foodstuff raises the serious concern that BSE may now be present in sheep without being distinguishable from scrapie. Sensitive models are urgently needed given the dramatic consequences of such a possible contamination on animal and human health. We inoculated transgenic mice expressing the ovine PrP gene with a brain homogenate from sheep experimentally infected with BSE. We found numerous typical florid plaques in their brains. Such florid plaques are a feature of vCJD in humans and experimental BSE infection in macaques. Our observation represents the first description, after a primary infection, of this hallmark in a transgenic mouse model. Moreover, these mice appear to be a promising tool in the search for BSE in sheep.
Molecular and Cellular Neuroscience | 2006
Carole Crozet; Julien Vézilier; Virginie Delfieu; Takuya Nishimura; Takashi Onodera; Danielle Casanova; Sylvain Lehmann; Florence Béranger
The mechanisms of prion-induced neurological dysfunction observed in prion diseases are poorly understood. Transgenic mice expressing a truncated form of the prion protein (23-230 PrP) acquire cerebellar degeneration (Ma and Lindquist, Science, 2002). To decipher the mechanisms of neurodegeneration induced by 23-230 PrP, we established inducible cell lines expressing this truncated form of PrP. We found that 23-230 PrP, expected to be cytosolic, accumulated mostly in the nucleus of the cells and was not cytotoxic. Nuclear localization of this mutant form of PrP is independent of its predicted nuclear localization signals. In contrast to what we previously described for PrPSc, nuclear accumulation of 23-230 PrP does not require a functional microtubule network. We observed that 23-230 PrP interacts with chromatin in vivo, as already described for recombinant PrP and for PrPSc. Our data demonstrate that the 23-230 PrP model does not reflect the situation of a cytosolic PrP but could represent a very useful tool to understand the consequences of the accumulation of the prion protein in the nucleus.
Molecular Cell | 2013
Siem van der Laan; Nikolay Tsanov; Carole Crozet; Domenico Maiorano
The molecular mechanism underlying G1/S checkpoint bypass in mouse embryonic stem cells (ESCs) remains unknown. DNA damage blocks S phase entry by inhibiting the CDK2 kinase through destruction of its activator, the Cdc25A phosphatase. We observed high Cdc25A levels in G1 that persist even after DNA damage in mouse ESCs. We also found higher expression of Dub3, a deubiquitylase that controls Cdc25A protein abundance. Moreover, we demonstrate that the Dub3 gene is a direct target of Esrrb, a key transcription factor of the self-renewal machinery. We show that Dub3 expression is strongly downregulated during neural conversion and precedes Cdc25A destabilization, while forced Dub3 expression in ESCs becomes lethal upon differentiation, concomitant to cell-cycle remodeling and lineage commitment. Finally, knockdown of either Dub3 or Cdc25A induced spontaneous differentiation of ESCs. Altogether, these findings couple the self-renewal machinery to cell-cycle control through a deubiquitylase in ESCs.
PLOS ONE | 2008
Karine Toupet; Valérie Compan; Carole Crozet; Chantal Mourton-Gilles; Nadine Mestre-Francés; Françoise Ibos; Pierre Corbeau; Jean-Michel Verdier; Véronique Perrier
Classical drug therapies against prion diseases have encountered serious difficulties. It has become urgent to develop radically different therapeutic strategies. Previously, we showed that VSV-G pseudotyped FIV derived vectors carrying dominant negative mutants of the PrP gene are efficient to inhibit prion replication in chronically prion-infected cells. Besides, they can transduce neurons and cells of the lymphoreticular system, highlighting their potential use in gene therapy approaches. Here, we used lentiviral gene transfer to deliver PrPQ167R virions possessing anti-prion properties to analyse their efficiency in vivo. Since treatment for prion diseases is initiated belatedly in human patients, we focused on the development of a curative therapeutic protocol targeting the late stage of the disease, either at 35 or 105 days post-infection (d.p.i.) with prions. We observed a prolongation in the lifespan of the treated mice that prompted us to develop a system of cannula implantation into the brain of prion-infected mice. Chronic injections of PrPQ167R virions were done at 80 and 95 d.p.i. After only two injections, survival of the treated mice was extended by 30 days (20%), accompanied by substantial improvement in behaviour. This delay was correlated with: (i) a strong reduction of spongiosis in the ipsilateral side of the brain by comparison with the contralateral side; and (ii) a remarkable decrease in astrocytic gliosis in the whole brain. These results suggest that chronic injections of dominant negative lentiviral vectors into the brain, may be a promising approach for a curative treatment of prion diseases.
The Journal of Infectious Diseases | 2006
Jérôme Solassol; Manuela Pastore; Carole Crozet; Véronique Perrier; Sylvain Lehmann
With the appearance of variant Creutzfeldt-Jakob disease (CJD) and the detection of infectious prions in the peripheral organs of persons with sporadic CJD, the development of decontamination methods that are compatible with medical equipment has become a major issue. Here, we show that a formulation of copper metal ions in combination with hydrogen peroxide dramatically reduces the level of prion protein (PrP)(Sc) (the scrapie isoform of PrP) present in homogenates of samples from prion-infected brains, including brain samples from humans with CJD. An animal bioassay confirmed the reduction in prion infectivity, indicating that this novel Cu(2+)-H(2)O(2) formulation has great potential for prion decontamination.