References of "Jolois, Olivier"
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See detailDexamethasone inhibits the HSV-tk/ ganciclovir bystander effect in malignant glioma cells.
Robe, Pierre ULg; Nguyen-Khac, Minh-Tuan ULg; Jolois, Olivier ULg et al

in BMC Cancer (2005), 5

BACKGROUND: HSV-tk/ ganciclovir (GCV) gene therapy has been extensively studied in the setting of brain tumors and largely relies on the bystander effect. Large studies have however failed to demonstrate ... [more ▼]

BACKGROUND: HSV-tk/ ganciclovir (GCV) gene therapy has been extensively studied in the setting of brain tumors and largely relies on the bystander effect. Large studies have however failed to demonstrate any significant benefit of this strategy in the treatment of human brain tumors. Since dexamethasone is a frequently used symptomatic treatment for malignant gliomas, its interaction with the bystander effect and the overall efficacy of HSV-TK gene therapy ought to be assessed. METHODS: Stable clones of TK-expressing U87, C6 and LN18 cells were generated and their bystander effect on wild type cells was assessed. The effects of dexamethasone on cell proliferation and sensitivity to ganciclovir were assessed with a thymidine incorporation assay and a MTT test. Gap junction mediated intercellular communication was assessed with microinjections and FACS analysis of calcein transfer. The effect of dexamethasone treatment on the sensitivity of TK-expressing to FAS-dependent apoptosis in the presence or absence of ganciclovir was assessed with an MTT test. Western blot was used to evidence the effect of dexamethasone on the expression of Cx43, CD95, CIAP2 and BclXL. RESULTS: Dexamethasone significantly reduced the bystander effect in TK-expressing C6, LN18 and U87 cells. This inhibition results from a reduction of the gap junction mediated intercellular communication of these cells (GJIC), from an inhibition of their growth and thymidine incorporation and from a modulation of the apoptotic cascade. CONCLUSION: The overall efficacy of HSV-TK gene therapy is adversely affected by dexamethasone co-treatment in vitro. Future HSV-tk/ GCV gene therapy clinical protocols for gliomas should address this interference of corticosteroid treatment. [less ▲]

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See detailDistribution of nerve fibers and prion protein expression in mouse Peyer's patches
Defaweux, Valérie ULg; Dorban, G; Demonceau, C et al

Poster (2004, July)

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See detailFDC-B1: a new monoclonal antibody directed against bovine follicular dendritic cells
Defaweux, Valérie ULg; Mélot, France ULg; Jolois, Olivier ULg et al

in Veterinary Immunology and Immunopathology (2004), 97(1-2), 1-9

Follicular dendritic cells (FDCs) are a unique population of accessory cells located in the light zone of the germinal centres of lymphoid follicles. Their involvement in the generation of Immoral immune ... [more ▼]

Follicular dendritic cells (FDCs) are a unique population of accessory cells located in the light zone of the germinal centres of lymphoid follicles. Their involvement in the generation of Immoral immune responses implies a potential role for these cells in many disorders. Indeed, in prion diseases, FDCs seem to be the major sites of extraneuronal cellular prion protein expression and the principal sites of the infectious agent accumulation in lymphoid organs. The identification of FDC is useful for the analysis of their distribution in reactive lymphoid tissue as well as in pathological conditions. The production and characterisation of a new mouse monoclonal antibody directed against bovine follicular dendritic cells (FDC-B1) is reported. The antigen detected by FDC-B1 is expressed exclusively on the surface of FDCs in ruminant lymphoid organs. The antigen has an approximate molecular weight of 28 kDa. (C) 2003 Elsevier B.V. All rights reserved. [less ▲]

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See detailModulation of the HSV-TK/ganciclovir bystander effect by n-butyrate in glioblastoma: correlation with gap-junction intercellular communication.
Robe, Pierre ULg; Jolois, Olivier ULg; Nguyen Khac, Minh-Tuan ULg et al

in International Journal of Oncology (2004), 25(1), 187-92

The efficacy of HSV-TK/ganciclovir gene therapy largely relies on the bystander effect, i.e. the ability of transfected cells to kill the adjacent, untrasfected cells. This mechanism itself depends ... [more ▼]

The efficacy of HSV-TK/ganciclovir gene therapy largely relies on the bystander effect, i.e. the ability of transfected cells to kill the adjacent, untrasfected cells. This mechanism itself depends chiefly on the transfer via gap junctions of phosphorylated ganciclovir between cells, and is often deficient in glioblastomas. In this report, we demonstrate that n-butyrate markedly enhances the gap junction intercellular communication of GJIC-deficient glioma cells, and significantly increases the bystander effect in such cells. This effect of n-butyrate appears to be independent from its HDAC inhibitory effect, since trichostatin A does not reproduce it. [less ▲]

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See detailIn vitro and in vivo activity of the nuclear factor-kappa B inhibitor sulfasalazine in human glioblastomas.
Robe, Pierre ULg; Bentires-Alj, Mohamed; Bonif, Marianne et al

in Clinical Cancer Research : An Official Journal of the American Association for Cancer Research (2004), 10(16), 5595-603

Glioblastomas, the most common primary brain cancers, respond poorly to current treatment modalities and carry a dismal prognosis. In this study, we demonstrated that the transcription factor nuclear ... [more ▼]

Glioblastomas, the most common primary brain cancers, respond poorly to current treatment modalities and carry a dismal prognosis. In this study, we demonstrated that the transcription factor nuclear factor (NF)-kappaB is constitutively activated in glioblastoma surgical samples, primary cultures, and cell lines and promotes their growth and survival. Sulfasalazine, an anti-inflammatory drug that specifically inhibits the activation of NF-kappaB, blocked the cell cycle and induced apoptosis in several glioblastoma cell lines and primary cultures, as did gene therapy with a vector encoding a super-repressor of NF-kappaB. In vivo, sulfasalazine also significantly inhibited the growth of experimental human glioblastomas in nude mice brains. Given the documented safety of sulfasalazine in humans, these results may lead the way to a new class of glioma treatment. [less ▲]

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See detailDistribution of nerve fibres and prion protein expression in mice Peyer’s patches
Defaweux, Valérie ULg; Dorban, G.; Demonceau, C. et al

Poster (2003, October)

Prion pathogenesis following oral exposure is thought to involve gut-associated lymphoid tissue, which includes Peyer’s patches (PP). The antigens enter into the underlying lymphoid tissue organized in PP ... [more ▼]

Prion pathogenesis following oral exposure is thought to involve gut-associated lymphoid tissue, which includes Peyer’s patches (PP). The antigens enter into the underlying lymphoid tissue organized in PP through the medium of M cells. Infectious prion protein (PrPres) would probably take the same way of entry and like this initiate the first stage of lympho-invasion. Theoretically, intestinal lymphoid cells can come in contact with ingested PrPres and with nerve endings of the intramural system. The distribution pattern of the nerve fibres and lymphoid cells in PP and possible contact between these two elements implicated in neuroinvasion are not yet fully elucidated. In our study, classical immunoperoxydase staining and double immunofluorescence staining analysed with a confocal microscope has been carried out on C56Bl/6 mice PP. Immunoperoxidase and immunofluorescent CD11c stainings show numerous dendritic cells (DC) in the suprafollicular dome, close to the epithelium made of enterocytes and M-cells. Confocal studies show the presence of DC in the T cell zones of Peyer's patches, and also close to B cells in the follicule and to follicular dendritic cells (FDC) in the germinal centres. The PrPc expression, fundamental in the pathogenesis of prion diseases, is notably localized in germinal centres, co-localized with the FDC network and on cellular structures close to the epithelium, co-localized with DC. Nerve fibres have been immunostained in fluorescence using antibodies raised against neurofilaments High, Medium and Low and against glial fibrillary acidic protein (GFAP). Only GFAP staining revealed the presence of some nerve fibres in the suprafollicular dome, coursing the mucosal epithelium and also at the periphery of germinal centres in close connection with numerous dendritic cells. Such results permit us to postulate that these nerve fibres and PrPc positive dendritic cells, strategically positioned under the intestinal epithelium as well as in the germinal centres close to FDC network, highly expressing PrPc and thought to replicate PrPres, may be involved in the peripheral transport of the infectious prion protein. [less ▲]

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See detailDifferential involvement of the hMRE11/hRAD50/NBS1 complex, BRCA1 and MLH1 in NF-kappa B activation by camptothecin and X-ray
Habraken, Yvette ULg; Jolois, Olivier ULg; Piette, Jacques ULg

in Oncogene (2003), 22(38), 6090-6099

Camptothecin (CPT) and X-ray (XR) generate double-strand breaks (DSB) that can be processed by homologous or nonhomologous recombination. We studied the participation of proteins involved in recombination ... [more ▼]

Camptothecin (CPT) and X-ray (XR) generate double-strand breaks (DSB) that can be processed by homologous or nonhomologous recombination. We studied the participation of proteins involved in recombination pathways and cell cycle control in the signal transduction between DNA damage and NF-kappaB. Cells harbouring mutated NBS, hMRE11, BRCA1 or MLH1 were analysed. NBS- and hMRE11-deficient cells present a classical kinetic of NF-kappaB induction after camptothecin treatment. When DSB are generated by XR, NBS-deficient cells exhibit a delayed and strongly reduced level of NF-kappaB induction, whereas the hMRE11 mutated cells do not induce NF-kappaB at all. This indicates an important role of the hMRE11/hRAD50/NBS complex in the signal transduction initiated by XR. In HCC1937 cells that express a truncated version of BRCA1, XR induces a very rapid and transient NF-kappaB activation, whereas CPT leads to a delayed activation suggesting that BRCA1 modulates the transduction pathways in different manners after these two stresses. Finally, we found that a proficient MMR pathway is essential to the NF-kappaB activation after both CPT and XR. These results indicate that DSB originating from XR or CPT do not induce NF-kappaB in a unique way. MMR participates in both cascades, whereas the hMRE11/hRAD50/NBS trimer is specifically involved in the response elicited by XR. [less ▲]

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See detailFDC-B1, a new monoclonal antibody directed against bovine follicular dendrititic cells.
Defaweux, Valérie ULg; Mélot, France ULg; Jolois, Olivier ULg et al

Poster (2003, March)

Follicular dendritic cells (FDCs) are unique immunological accessory cells located in the light and dark zones of the germinal centres in lymph follicles. Characterized by long branching processes forming ... [more ▼]

Follicular dendritic cells (FDCs) are unique immunological accessory cells located in the light and dark zones of the germinal centres in lymph follicles. Characterized by long branching processes forming a three-dimensional network, FDCs create particular microenvironments for germinal centre B and T cells and contribute to the maturation of B cells into memory cells. An involvement of the FDCs is suspected in various disorders affecting lymphoid tissues, malignant lymphoma or in some viral diseases. Moreover, in prion diseases, FDCs seem to be the major sites of extraneuronal cellular prion protein expression and the principal sites of the infectious agent accumulation in lymph organs. Because no antibody commercially available was specific to bovine FDCs, a new monoclonal antibody directed against bovine FDCs (FDC-B1) has been produced and characterized in our laboratory. The antigen detected by FDC-B1 is expressed on FDC surfaces in ruminant (bovine, ovine and caprine) lymphoid organs. This protein seems to be a membrane glycoprotein of more or less 28 kDa whose sequence will be soon determined. Moreover, FDC-B1 can be used in various applications: immunofluorescence, immunoperoxidase, immunogold labellings and western blotting. FDCs are potential targets for therapy or prophylaxis in natural TSEs, such as bovine spongiform encephalopathies and scrapie. Thus, it appears of great interest to identify bovine and ovine FDCs in routine lymphoid tissues sections. An other application of this antibody to immunofluorescence histochemistry techniques will enable the study of possible direct contacts between bovine FDCs and nerve endings and thus clarify prions neuroinvasion scheme in the case of BSE and scrapie. [less ▲]

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See detailDo Bovine Lymphocytes Express a Peculiar Prion Protein?
Mélot, France ULg; Thielen, Caroline ULg; Labiet, T. et al

in Developmental Immunology (2002), 9(4), 245-52

The cellular prion protein (PrPc) is a glycolipid-anchored cell surface protein that usually exhibits three glycosylation states. Its post-translationally modified isoform, PrPsc, is involved in the ... [more ▼]

The cellular prion protein (PrPc) is a glycolipid-anchored cell surface protein that usually exhibits three glycosylation states. Its post-translationally modified isoform, PrPsc, is involved in the pathogenesis of various transmissible spongiform encephalopathies (TSEs). In bovine species, BSE infectivity appears to be restricted to the central nervous system; few or no detectable infectivity is found in lymphoid tissues in contrast to scrapie or variant CJD. Since expression of PrPc is a prerequisite for prion replication, we have investigated PrPc expression by bovine immune cells. Lymphocytes from blood and five different lymph organs were isolated from the same animal to assess intra- and interindividual variability of PrPc expression, considering six individuals. As shown by flow cytometry, this expression is absent or weak on granulocytes but is measurable on monocytes, B and T cells from blood and lymph organs. The activation of the bovine cells produces an upregulation of PrPc. The results of our in vitro study of PrPc biosynthesis are consistent with previous studies in other species. Interestingly, western blotting experiments showed only one form of the protein, the diglycosylated band. We propose that the glycosylation state could explain the lack of infectivity of the bovine immune cells. [less ▲]

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See detailSpermine induces precocious development of the spleen in mice
Jolois, Olivier ULg; Peulen, Olivier ULg; Collin, Serge ULg et al

in Experimental Physiology (2002), 87(1), 69-75

Spermine is a low molecular weight polyamine involved in the postnatal maturation of the gut. When it is administered orally to suckling rats, it induces maturation of the intestinal tract (liver ... [more ▼]

Spermine is a low molecular weight polyamine involved in the postnatal maturation of the gut. When it is administered orally to suckling rats, it induces maturation of the intestinal tract (liver, pancreas and small intestine). Here we show that this polyamine is able to induce precocious intestinal and splenic development in suckling mice. In fact, in 15-day-old mice which had received spermine orally twice daily for 3 days we observed an increase in the ratio of white pulp surface to total spleen surface in comparison with untreated mice. The two macrophage subsets of the marginal zone and the B-cell population were more developed and reached the development level of 5- or 10-week-old mice. The proliferation rate of B-cells was increased by spermine administration to pups. These observations suggest that spermine might play a role in immune system development; further investigation of its effects are intended, namely the evaluation of its capacity to enhance defence during the neonatal period. [less ▲]

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See detailDNA immunisation. New histochemical and morphometric data.
Ehirchiou, D.; Zorzi, Willy ULg; Biemans, R. et al

in European Journal of Histochemistry (2002), 46(3), 215-22

Splenic germinal center reactions were measured during primary response to a plasmidic DNA intramuscular injection. Cardiotoxin-pretreated Balb/c mice were immunized with DNA plasmids encodmg or not the ... [more ▼]

Splenic germinal center reactions were measured during primary response to a plasmidic DNA intramuscular injection. Cardiotoxin-pretreated Balb/c mice were immunized with DNA plasmids encodmg or not the SAG1 protein, a membrane antigen of Toxoplasma gondii. Specific anti-SAG1 antibodies were detected on days 16 and 36 after injection of coding plasmids. The results of ELISAs showed that the SAG1-specific antibodies are of the IgG2a class. Morphometric analyses were done on serial immunostained cryosections of spleen and draining or non-draining lymph nodes. This new approach made it possible to evaluate the chronological changes induced by DNA immunisation in the germinal centres (in number and in size). Significant increases in the number of germinal centres were measured in the spleen and only in draining lymph nodes after plasmid injection, the measured changes of the germinal centers appeared to result from the adjuvant stimulatory effect of the plasmidic DNA since both the coding and the noncoding plasmid DNA induced them. No measurable changes were recorded in the T-dependent zone of lymph organs. [less ▲]

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See detailIsolation of Bovine Follicular Dendritic Cells Allows the Demonstration of a Particular Cellular Prion Protein
Thielen, Caroline ULg; Mélot, France ULg; Jolois, Olivier ULg et al

in Cell & Tissue Research (2001), 306(1), 49-55

As interaction of cellular prion protein (PrPc) and the infectious agent (PrPres) appears to be a crucial pathogenic step promoted by homology, variation in PrPc isoforms on bovine immune cells may ... [more ▼]

As interaction of cellular prion protein (PrPc) and the infectious agent (PrPres) appears to be a crucial pathogenic step promoted by homology, variation in PrPc isoforms on bovine immune cells may explain the absence of infectivity in most bovine lymph organs. In this study, we examined PrPc expression in bovine lymph organs (tonsils and lymph nodes) and on isolated follicular dendritic cells (FDCs). We used a panel of different monoclonal antibodies (MoAbs) raised against different epitopes of prion protein. Two MoAbs recognise amino acids 79-92 (SAF 34 and SAF 32 Mo-Abs); the 6H4 antibody reacts with a specific peptide comprising the 144-152 amino acids, and the 12F10 MoAb recognises the sequence 142-160. After immunolabelling of frozen sections of lymph organs with 6H4 or 12F10 MoAbs, we detected cellular prion protein in germinal centres. However, using the SAF 34 or SAF 32 antibodies, PrPc was revealed outside the lymphoid tissues. No PrPc was observed in the germinal centres. Therefore, we adapted the method of FDC isolation, making it suitable for the study of PrPc expression on their surface. Using electron microscopy, the presence of PrPc on the surface of FDCs was demonstrated only with 6H4 MoAb. These results suggest that bovine follicular dendritic cells express a particular form of prion protein. Either the N-terminal part of PrPc is cleaved or the accessibility of the specific epitope (79-92) of SAF 34 MoAb is abolished by interaction with other molecules. This particular isoform of PrPc on bovine FDCs might be related to the apparent absence of infectivity in lymph organs in cattle affected by bovine spongiform encephalopathy. [less ▲]

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See detailMechanism of Colon Cancer Cell Apoptosis Mediated by Pyropheophorbide-a Methylester Photosensitization
Matroule, Jean-Yves; Carthy, Chris M; Granville, David J et al

in Oncogene (2001), 20

Pyropheophorbide-a methylester (PPME) is a second generation of photosensitizers used in photodynamic therapy (PDT). We demonstrated that PPME photosensitization triggered apoptosis of colon cancer cells ... [more ▼]

Pyropheophorbide-a methylester (PPME) is a second generation of photosensitizers used in photodynamic therapy (PDT). We demonstrated that PPME photosensitization triggered apoptosis of colon cancer cells as measured by using several classical parameters such as DNA laddering, PARP cleavage, caspase activation and mitochondrial release of cytochrome c. Preincubation of cells with N-acetyl cysteine (NAC) or pyrolidine dithiocarbamate (PDTC) protected against apoptosis mediated by PPME photosensitization showing that reactive oxygen species (ROS) are involved as second messengers. On the other hand, photosensitization carried out in the presence of deuterium oxide (D2O) which enhances singlet oxygen (1O2) lifetime only increases necrosis without affecting apoptosis. Since PPME was localized in the endoplasmic reticulum (ER)/Golgi system and lysosomes, other messengers than ROS were tested such as calcium, Bid, Bap31, phosphorylated Bcl-2 and caspase-12 but none was clearly identified as being involved in triggering cytochrome c release from mitochondria. On the other hand, we demonstrated that the transduction pathways leading to NF-kappaB activation and apoptosis were clearly independent although NF-kappaB was shown to counteract apoptosis mediated by PPME photosensitization. [less ▲]

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See detailDoes spleen innervation influence TSE pathogenesis?
Jolois, Olivier ULg; Farquhar, Christine; Brown, Karen et al

Poster (2001)

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See detailSpermine induces precocious development of the spleen in Wistar rat
Peulen, Olivier ULg; Jolois, Olivier ULg; Galopin, Catherine et al

in Trends in Comparative Biochemistry and Physiology (2001), 8

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See detailEvidence of rainbow trout prolactin interaction with its receptor through unstable homodimerisation.
Le Rouzic, Philippe; Sandra, Olivier; Grosclaude, Jeanne et al

in Molecular & Cellular Endocrinology (2001), 172(1-2), 105-13

This study aims to characterise Prolactin receptor (PRLR) in rainbow trout for which no information is available despite the availability of Salmonid PRL preparations. By screening a freshwater rainbow ... [more ▼]

This study aims to characterise Prolactin receptor (PRLR) in rainbow trout for which no information is available despite the availability of Salmonid PRL preparations. By screening a freshwater rainbow trout intestine cDNA library with a probe corresponding to the extracellular domain (ECD) of tilapia PRLR, we have cloned a 2.5 kb insert coding for the PRLR. The mature protein of 614 amino acid residues is similar to PRLR isolated in tilapia and also the long form of mammalian PRLR. Analysis of PRLR gene expression in osmoregulatory organs revealed the presence of a unique transcript, thus confirming the involvement of this hormone in the control of osmoregulation in this fish species. By using surface plasmon resonance (SPR) technology, kinetic measurement of interaction between trout PRL and its receptor ECD was studied. This approach allowed us to demonstrate the formation of a transient, unstable homodimeric complex. This unstability could explain the inability to perform binding experiments using homologous PRL. In contrast, heterologous lactogenic ligands were able to interact through a more stable complex. Whether these characteristics of PRL-receptor interaction in rainbow trout are different to what occurs in tilapia where a homologous radioreceptor assay was developed would require further studies. [less ▲]

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See detailDifferential Expression of Cellular Prion Protein on Human Blood and Tonsil Lymphocytes
Antoine, Nadine ULg; Cesbron, J. Y.; Coumans, Bernard ULg et al

in Haematologica (2000), 85(5), 475-80

BACKGROUND AND OBJECTIVE: The expression of cellular prion protein (PrPc) on the surface of peripheral lymphocytes has been previously reported, but little is known about its expression on lymphoid cells ... [more ▼]

BACKGROUND AND OBJECTIVE: The expression of cellular prion protein (PrPc) on the surface of peripheral lymphocytes has been previously reported, but little is known about its expression on lymphoid cells from secondary lymph organs. In this report, we compare the surface expression of PrPc on human blood lymphocytes and tonsil lymphocytes. DESIGN AND METHODS: This analysis was performed by cytometry on live lymphocytes isolated from healthy donors or from the tonsils of adults or children. RESULTS: Human peripheral lymphocytes and tonsillar lymphoid cells, but not erythrocytes or granulocytes, express PrPc at their surfaces. Interestingly, we found significantly less PrPc on freshly isolated tonsil lymphocytes, both B and T, than on blood cells. Although tonsil cells bear less PrPc than circulating blood lymphocytes, they are able to express high quantities of PrPc on their surface when placed in culture. However, contrary to previous results, mitogen stimulation does not affect this expression on B- or T-cells. INTERPRETATION AND CONCLUSIONS: We suggest that the PrPc expression by lymphocytes may be modified by interactions occurring during intratissular migration or during cell-to-cell contacts. Whether PrPc plays a role in intracellular communication at this location, as it does in the nervous system, remains an open question. [less ▲]

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