Dexamethasone inhibits the HSV-tk/ ganciclovir bystander effect in malignant glioma cells.
Robe, Pierre ; Nguyen-Khac, Minh-Tuan ; Jolois, Olivier 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 ▲]Detailed reference viewed: 36 (4 ULg)
Nestin-positive mesenchymal stem cells favour the astroglial lineage in neural progenitors and stem cells by releasing active BMP4.
Wislet-Gendebien, Sabine ; Bruyere, Françoise ; Hans, Grégory et al
in BMC Neuroscience (2004), 5
BACKGROUND: Spontaneous repair is limited after CNS injury or degeneration because neurogenesis and axonal regrowth rarely occur in the adult brain. As a result, cell transplantation has raised much ... [more ▼]
BACKGROUND: Spontaneous repair is limited after CNS injury or degeneration because neurogenesis and axonal regrowth rarely occur in the adult brain. As a result, cell transplantation has raised much interest as potential treatment for patients with CNS lesions. Several types of cells have been considered as candidates for such cell transplantation and replacement therapies. Foetal brain tissue has already been shown to have significant effects in patients with Parkinson's disease. Clinical use of the foetal brain tissue is, however, limited by ethical and technical problems as it requires high numbers of grafted foetal cells and immunosuppression. Alternatively, several reports suggested that mesenchymal stem cells, isolated from adult bone marrow, are multipotent cells and could be used in autograft approach for replacement therapies. RESULTS: In this study, we addressed the question of the possible influence of mesenchymal stem cells on neural stem cell fate. We have previously reported that adult rat mesenchymal stem cells are able to express nestin in defined culture conditions (in the absence of serum and after 25 cell population doublings) and we report here that nestin-positive (but not nestin-negative) mesenchymal stem cells are able to favour the astroglial lineage in neural progenitors and stem cells cultivated from embryonic striatum. The increase of the number of GFAP-positive cells is associated with a significant decrease of the number of Tuj1- and O4-positive cells. Using quantitative RT-PCR, we demonstrate that mesenchymal stem cells express LIF, CNTF, BMP2 and BMP4 mRNAs, four cytokines known to play a role in astroglial fate decision. In this model, BMP4 is responsible for the astroglial stimulation and oligodendroglial inhibition, as 1) this cytokine is present in a biologically-active form only in nestin-positive mesenchymal stem cells conditioned medium and 2) anti-BMP4 antibodies inhibit the nestin-positive mesenchymal stem cells conditioned medium inducing effect on astrogliogenesis. CONCLUSIONS: When thinking carefully about mesenchymal stem cells as candidates for cellular therapy in neurological diseases, their effects on resident neural cell fate have to be considered. [less ▲]Detailed reference viewed: 86 (3 ULg)
In vitro and in vivo activity of the nuclear factor-kappa B inhibitor sulfasalazine in human glioblastomas.
Robe, Pierre ; ; 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 ▲]Detailed reference viewed: 59 (6 ULg)
Kinetic properties of the alpha(2) homo-oligomeric glycine receptor impairs a proper synaptic functioning
; ; et al
in Journal of Physiology-London (2003), 553(2), 369-386
Ionotropic glycine receptors (GlyRs) are present in the central nervous system well before the establishment of synaptic contacts. Immature nerve cells are known, at least in the spinal cord, to express ... [more ▼]
Ionotropic glycine receptors (GlyRs) are present in the central nervous system well before the establishment of synaptic contacts. Immature nerve cells are known, at least in the spinal cord, to express alpha(2) homomeric GlyRs, the properties of which are relatively unknown compared to those of the adult synaptic form of the GlyR (mainly alpha(1)/beta heteromeres). Here, the kinetics properties of GlyRs at the single-channel level have been recorded in real-time by means of the patch-clamp technique in the outside-out configuration coupled with an ultra-fast flow application system (< 100 µs). Recordings were performed on chinese hamster ovary (CHO) cells stably transfected with the a, GlyR subunit. We show that the onset, the relaxation and the desensitisation of α(2) homomeric GlyR-mediated currents are slower by one or two orders of magnitude compared to synaptic mature GlyRs and to other ligand-gated ionotropic channels involved in fast synaptic transmission. First latency analysis performed on single GlyR channels revealed that their slow activation time course was due to delayed openings. When synaptic release of glycine was mimicked (1 mM glycine; 1 ms pulse duration), the opening probability of α(2) homomeric GlyRs was low (P-o ≈ 0.1) when compared to mature synaptic GlyRs (P-o = 0.9). This low P-o is likely to be a direct consequence of the relatively slow activation kinetics of α(2) homomeric GlyRs when compared to the activation kinetics of mature α(1)/β GlyRs. Such slow kinetics suggest that embryonic α(2) homomeric GlyRs cannot be activated by fast neurotransmitter release at mature synapses but rather could be suited for a non-synaptic paracrine-like release of agonist, which is known to occur in the embryo. [less ▲]Detailed reference viewed: 21 (0 ULg)
Regulation of neural markers nestin and GFAP expression by cultivated bone marrow stromal cells.
Wislet-Gendebien, Sabine ; Leprince, Pierre ; Moonen, Gustave et al
in Journal of Cell Science (2003), 116(Pt 16), 3295-302
Bone marrow stromal cells can differentiate into many types of mesenchymal cells, i.e. osteocyte, chondrocyte and adipocyte, but can also differentiate into non-mesenchymal cells, i.e. neural cells under ... [more ▼]
Bone marrow stromal cells can differentiate into many types of mesenchymal cells, i.e. osteocyte, chondrocyte and adipocyte, but can also differentiate into non-mesenchymal cells, i.e. neural cells under appropriate in vivo experimental conditions (Kopen et al., 1999; Brazelton et al., 2000; Mezey et al., 2000). This neural phenotypic plasticity allows us to consider the utilization of mesenchymal stem cells as cellular material in regenerative medicine. In this study, we demonstrate that cultured adult rat stromal cells can express nestin, an intermediate filament protein predominantly expressed by neural stem cells. Two factors contribute to the regulation of nestin expression by rat stromal cells: serum in the culture medium inhibits nestin expression and a threshold number of passages must be reached below which nestin expression does not occur. Only nestin-positive rat stromal cells are able to form spheres when they are placed in the culture conditions used for neural stem cells. Likewise, only nestin-positive stromal cells are able to differentiate into GFAP (glial fibrillary acidic protein)-positive cells when they are co-cultivated with neural stem cells. We thus demonstrated that adult rat stromal cells in culture express nestin in absence of serum after passaging the cells at least ten times, and we suggest that nestin expression by these cells might be a prerequisite for the acquisition of the capacity to progress towards the neural lineage. [less ▲]Detailed reference viewed: 98 (4 ULg)
What are the realistic hopes for remyelinisation in the central nervous system ?
in Bulletin de l'Académie Nationale de Médecine (2003), 158Detailed reference viewed: 33 (0 ULg)
What are the realistic hopes for stem cells in neurological diseases ?
in Bulletin de l'Académie Nationale de Médecine (2003), 158Detailed reference viewed: 11 (2 ULg)
Nestin expression in cultivated mesenchymal stem cells: Regulation and potential role in their neural differentiation
Wislet-Gendebien, Sabine ; Leprince, Pierre ; Moonen, Gustave et al
in Glia (2002, May), (Suppl. 1), 87
Bone marrow stromal cells can differentiate into many types of mesenchymal cells, i.e. osteocyte, chondrocyte, fibroblast and adipocyte, but can also differentiate into non-mesenchymal cell, i.e. neural ... [more ▼]
Bone marrow stromal cells can differentiate into many types of mesenchymal cells, i.e. osteocyte, chondrocyte, fibroblast and adipocyte, but can also differentiate into non-mesenchymal cell, i.e. neural cells in appropriate in vivo experimental conditions (Kopen and al.,PNAS,96, 10711,1999, Brazelton and al, Science, 290,1175, 2000, Mezey and al, Science, 290,1179, 2000). In neurological disorders, such as Alzheimer's and Parkinson's diseases, auto-transplantation of neural cell types derived from mesenchymal stem cells offers the potential of replacing lost cells and recovering lost functions. Nestin is an intermediate filament protein predominantly expressed by neural stem cells and is used to identify neural progenitor. In this study, we demonstrate that cultured rat mesenchymal stem cells (rMSC) can express nestin in appropriate conditions. Two factors contribute to the regulation of nestin expression by rMSC : 1) the presence of serum-derived components in the culture medium which repress nestin expression and 2) the cell’s number of passages. LPA and thrombin mimic this serum effect. Furthermore, when nestin- positive cells are trypsinized and resuspended into culture conditions used for neural stem cells (NSC), sphere formation is observed. Likewise, by co-cultivating nestin-positive rMSC with NSC derived from green mouse, heterogenous spheres were obtained. When those heterogenous spheres are placed on polyornithine-coated surfaces, a differentiation of some rMSC into GFAP-positive cells occurs. These results indicate that nestin expression might be a pre-requisite for the acquisition by rMSC of the capacity to differentiate into some neural cell types. [less ▲]Detailed reference viewed: 141 (4 ULg)
Functional glycine receptors are expressed by postnatal nestin-positive neural stem/progenitor cells
Nguyen, Laurent ; Malgrange, Brigitte ; Belachew, Shibeshih et al
in European Journal of Neuroscience (2002), 15(8), 1299-1305
Multipotent neural stem and progenitor cells (NS/PCs) are well-established cell subpopulations occurring in the developing, and also in the mature mammalian nervous systems. Trophic and transcription ... [more ▼]
Multipotent neural stem and progenitor cells (NS/PCs) are well-established cell subpopulations occurring in the developing, and also in the mature mammalian nervous systems. Trophic and transcription factors are currently the main signals known to influence the development and the commitment of NS/PCs and their progeny. However, recent studies suggest that neurotransmitters could also contribute to neural development. In that respect, rodent-cultured embryonic NS/PCs have been reported to express functional neurotransmitter receptors. No similar investigation has, however, been made in postnatal and/or in adult rodent brain stem cells. In this study, using RT-PCR and immunocytochemical methods, we show that alpha(1) -, alpha(2) - and beta-subunit mRNAs and alpha-subunit proteins of the glycine ionotropic receptor are expressed by 80.5 +/- 0.9% of postnatal rat striatum-derived, nestin-positive cells within cultured neurospheres. Whole-cell patch-clamp experiments further demonstrated that glycine triggers in 33.5% of these cells currents that can be reversibly blocked by strychnine and picrotoxin. This demonstrates that NS/PCs express functional glycine receptors, the consequence(s) of their activation remaining unknown. [less ▲]Detailed reference viewed: 41 (1 ULg)
Proliferative generation of mammalian auditory hair cells in culture
Malgrange, Brigitte ; Belachew, Shibeshih ; Thiry, Marc et al
in Mechanisms of Development (2002), 112(1-2), 79-88Detailed reference viewed: 35 (6 ULg)
Quels espoirs de remyélinisation dans la sclérose en plaques ?
Rogister, Bernard ; Wislet, Sabine ; Belachew, Shibeshih
in Agenda Psychiatrie (L') (2002), 24Detailed reference viewed: 58 (9 ULg)
Les facteurs neurotrophiques : un mythe thérapeutique ?
in Ahead in Neurology (2002), 5(1), 3-20Detailed reference viewed: 18 (0 ULg)
Etude moléculaire et cellulaire des phénomènes de plasticité phénotypique nerveuse des cellules souches mésenchymateuses.
Wislet, Sabine ; Rogister, Bernard
Conference (2002)Detailed reference viewed: 12 (0 ULg)
Neurotransmitters as Early Signals for Central Nervous System Development
Nguyen, Laurent ; ; et al
in Cell & Tissue Research (2001), 305(2), 187-202
During brain ontogenesis, the temporal and spatial generation of the different types of neuronal and glial cells from precursors occurs as a sequence of successive progenitor stages whose proliferation ... [more ▼]
During brain ontogenesis, the temporal and spatial generation of the different types of neuronal and glial cells from precursors occurs as a sequence of successive progenitor stages whose proliferation, survival and cell-fate choice are controlled by environmental and cellular regulatory molecules. Neurotransmitters belong to the chemical microenvironment of neural cells, even at the earliest stages of brain development. It is now established that specific neurotransmitter receptors are present on progenitor cells of the developing central nervous system and could play, during neural development, a role that has remained unsuspected until recently. The present review focuses on the occurrence of neurotransmitters and their corresponding ligand-gated ion channel receptors in immature cells, including neural stem cells of specific embryonic and neonatal brain regions. We summarize in vitro and in vivo data arguing that neurotransmitters could regulate morphogenetic events such as proliferation, growth, migration, differentiation and survival of neural precursor cells. The understanding of neurotransmitter function during early neural maturation could lead to the development of pharmacological tools aimed at improving adult brain repair strategies. [less ▲]Detailed reference viewed: 50 (3 ULg)
Neuregulin signaling regulates neural precursor growth and the generation of oligodendrocytes in vitro
; Rogister, Bernard ; et al
in Journal of Neuroscience (2001), 21Detailed reference viewed: 9 (1 ULg)
The SH2 domain containing 5-phosphatase SHIP2 is expressed in the germinal layers of embryo and adult mouse brain : increased expression in N_CAM deficient mice.
; ; et al
in Neuroscience (2001), 105Detailed reference viewed: 5 (0 ULg)
A 295-Kda Intermediate Filament-Associated Protein in Radial Glia and Developing Muscle Cells in Vivo and in Vitro
; Thiry, Marc ; et al
in Developmental Dynamics : An Official Publication of the American Association of Anatomists (2000), 219(4), 514-25
The RC2 antibody is frequently used to label mouse radial glial cells in all parts of the nervous system where neuronal migration occurs during embryonic and early postnatal life. The antigen recognized ... [more ▼]
The RC2 antibody is frequently used to label mouse radial glial cells in all parts of the nervous system where neuronal migration occurs during embryonic and early postnatal life. The antigen recognized by this antibody still needs to be identified. We have characterized further its localization in vivo, its expression and subcellular localization in vitro, as well as its molecular nature. Histologic investigations of whole mouse embryos reveal an equally intense expression of RC2 immunostaining in radial glial cells in brain and spinal cord and in skeletal muscle. In glial cells cultures, the RC2 antibody recognizes an epitope located on the glial cytoskeleton and identified as an intermediate filament associated protein (IFAP) at the ultrastructural level. RC2 immunostaining in those cells is strongly dependent on the presence of a serum-derived activity. Serum-removal causes a decrease of the staining while adding serum back to the cells induces reexpression of RC2 immunoreactivity. By Western blotting, we find that in intermediate filament (IF) preparations obtained from cultured cerebellar glia, the RC2 antibody recognizes a 295-kDa protein whose expression is also dependent on the presence of serum in culture medium. In developing muscle cells, RC2 immunostaining is observed from the myoblast stage and disappears after complete myotube fusion. Both in vivo and in vitro, staining is first seen as a loose capping around myoblasts nuclei and progressively concentrates into Z-disks in association with the muscle IF protein desmin. The RC2 antibody also recognizes a 295-kDa protein band in muscle tissue protein extracts. Thus, the RC2 antibody recognizes a developmentally regulated cytoskeletal protein that is expressed, like other previously identified IFAPs, by cells of the glial and myogenic lineages and whose expression in vitro seems to be controlled by a signaling mechanism known to modulate astroglial morphology. [less ▲]Detailed reference viewed: 78 (4 ULg)
La chirurgie du thymus, normal, involue ou tumoral
Limet, Raymond ; Rogister, Bernard
in Revue Médicale de Liège (2000), 55(10), 940-4
Thymoma is the most frequently resected mediastinal tumor. Its malignancy is related more to macroscopical findings than to microscopical analysis. All thymomas should be resected, in order to prevent ... [more ▼]
Thymoma is the most frequently resected mediastinal tumor. Its malignancy is related more to macroscopical findings than to microscopical analysis. All thymomas should be resected, in order to prevent malignant degeneration. Furthermore, for the treatment of myasthenia, several centers recommend resection of the thymus, either tumoral (thymoma) or atrophied. Although the role of surgery in this regard is controversial, all authors unanimously stress that complete resection of all thymic remnants is essential to achieve adequate results. [less ▲]Detailed reference viewed: 44 (3 ULg)