References of "Geenen, Vincent"
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See detailHistoire de la recherche biomédicale
Geenen, Vincent ULg

Learning material (2007)

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See detailIgf2 expression is required for complete immunological tolerance to insulin
Hansenne, Isabelle; Renard, Chantal; Geenen, Vincent ULg

Poster (2007, July)

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See detailEvaluation clinique de la fonction du thymus.
Castermans, Emilie ULg; Morrhaye, Gabriel ULg; Marchand, S. et al

in Revue Médicale de Liège (2007), 62(11), 675-8

The essential role of the thymus is to install an extremely diverse repertoire of T lymphocytes that are self-tolerant and competent against non-self, as well as to generate self-antigen specific ... [more ▼]

The essential role of the thymus is to install an extremely diverse repertoire of T lymphocytes that are self-tolerant and competent against non-self, as well as to generate self-antigen specific regulatory T cells (Treg) able to inactivate in periphery self-reactive T cells having escaped the thymic censorship. Although indirect, techniques of medical imaging and phenotyping of peripheral T cells may help in the investigation of thymic function. Nowadays however, thymopoiesis is better evaluated through quantification by PCR of T-cell receptor excision circles (TREC) generated by intrathymic random recombination of the gene segments coding for the variable parts of the T-cell receptor for antigen (TCR). The TREC methodology is very valuable in the circumstances not associated with intense proliferation or apoptosis of peripheral T lymphocytes. [less ▲]

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See detailEvaluation de la thymopoiese: applications cliniques.
Castermans, Emilie ULg; Morrhaye, Gabriel ULg; Marchand, S. et al

in Revue Médicale de Liège (2007), 62(12), 725-9

In the precedent article, we have described how T-cell generation in the thymus (thymopoiesis) may be currently evaluated through quantification by PCR of T-cell receptor excision circles (TREC) generated ... [more ▼]

In the precedent article, we have described how T-cell generation in the thymus (thymopoiesis) may be currently evaluated through quantification by PCR of T-cell receptor excision circles (TREC) generated by intrathymic random recombination of the gene segments coding for variable parts of T-cell receptor for antigen (TCR). In hematology, TREC methodology helps in a better understanding of immune reconstitution after graft of hematopoietic stem cells: first there is a proliferation of mature T cells present in the graft, then a differentiation of naive T cells. In geriatrics, the homeostasis of the peripheral T-cell repertoire is maintained through proliferation of peripheral memory T cells rather than through thymic generation of naive T cells. In addition, TREC quantification constitutes a novel major tool for deciphering the tight control of thymopoiesis by the neuroendocrine system. [less ▲]

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See detailDialogue between Blastocyst hCG and Endometrial LH/hCG Receptor: Which Role in Implantation?
PERRIER d'HAUTERIVE, Sophie ULg; Berndt, Sarah ULg; Tsampalas, Marie ULg et al

in Gynecologic & Obstetric Investigation (2007), 64(3), 156-60

The specific interaction of blastocyst-derived human chorionic gonadotropin (hCG) and endometrial LH/hCG-R constitutes a fundamental component of the molecular dialogue at the materno-fetal interface ... [more ▼]

The specific interaction of blastocyst-derived human chorionic gonadotropin (hCG) and endometrial LH/hCG-R constitutes a fundamental component of the molecular dialogue at the materno-fetal interface. From our observations and studies from other groups, hCG was indeed shown to play a significant role in implantation and tolerance of the embryo, decidual differentiation and remodeling, as well as in placentation. The profile pattern of LH/hCG-R expression by endometrial epithelium correlates with the theoretical timing of the implantation window. Studies are currently being conducted in assisted medical procreation and in an animal model of implantation to establish the index of LH/hCG-R expression as a new biomarker of uterine receptivity for embryo implantation. [less ▲]

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See detailLe rôle des virus dans la pathogénie du diabète de type 1
Geenen, Vincent ULg

Scientific conference (2006, December 05)

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See detailAngiogenic activity of human chorionic gonadotropin through LH receptor activation on endothelial and epithelial cells of the endometrium
Berndt, Sarah ULg; PERRIER d'HAUTERIVE, Sophie ULg; Blacher, Silvia ULg et al

in FASEB Journal (2006), 20(14), 2630-2632

Successful embryo development requires an extensive endometrial angiogenesis in proximity of implantation site. The glycoprotein hCG is produced even before implantation by trophoblast in normal pregnancy ... [more ▼]

Successful embryo development requires an extensive endometrial angiogenesis in proximity of implantation site. The glycoprotein hCG is produced even before implantation by trophoblast in normal pregnancy. In this manuscript, we demonstrate an angiogenic effect of hCG in several in vivo (chick chorioallantoic membrane, matrigel plug assay, aortic ring assay) and in vitro experimental models. In contrast, human placental lactogen (hPL) did not display angiogenic properties. LH/hCG receptor was detected in endothelial cells by reverse-transcriptase polymerase chain reaction (RT-PCR) and by Western blotting. In mice aortic ring assay, angiostimulation by hCG was abrogated by deletion of LH/hCG receptor (LuRKO mice). Use of recombinant hCG and anti-hCG antibody (Ab) further confirmed the specificity of this angiogenic activity. By using dibutyryl cAMP, adenylate cyclase, or protein kinase A inhibitors, we demonstrate that hCG-mediated angiogenesis involves adenylyl-cyclase-protein kinase A activation. Addition of hCG to endometrial epithelial epithelial cells, but not to cultured endothelial cells, stimulated vascular endothelial growth factor (VEGF). VEGF and hCG also displayed additive activities. Altogether, these data demonstrate that peritrophoblastic angiostimulation may result from a paracrine dialogue between trophoblast, epithelial, and endothelial cells through hCG and VEGF. [less ▲]

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See detailThymus-dependent T cell tolerance of neuroendocrine functions - Principles, reflections, and implications for tolerogenic/negative self-vaccination
Geenen, Vincent ULg

in Annals of the New York Academy of Sciences (2006), 1088

Under the evolutionary pressure exerted by the emergence of adaptive immunity and its inherent risk of horror autotoxicus, the thymus appeared some 500 million years ago as a novel lymphoid structure able ... [more ▼]

Under the evolutionary pressure exerted by the emergence of adaptive immunity and its inherent risk of horror autotoxicus, the thymus appeared some 500 million years ago as a novel lymphoid structure able to prevent autoimmunity and to orchestrate self-tolerance as a cornerstone in the physiology of the immune system. Also, the thymus plays a prominent role in T cell education to neuroendocrine principles. Some self-antigens (oxytocin, neurotensin, insulin-like growth factor 2 [IGF-2]) have been selected to be predominantly expressed in thymic epithelium and to be presented to thymus T cells for educating them to tolerate other antigens related to them. In the insulin family, IGF2 is dominantly transcribed in cortical (c) and medullary (m) thymic epithelial cells (TECs), whereas the insulin gene (INS) is expressed at low level by only a few subsets of mTECs. Intrathymic transcription of both IGF2 and INS is under the control of the autoimmune regulator (Aire) gene. The highest concentrations of IGF-2 in the thymus explain why this peptide is much more tolerated than insulin, and why tolerance to IGF-2 is so difficult to break by active immunization. The high level of tolerance to IGF-2 is correlated to the development of a tolerogenic/regulatory profile when the sequence B11-25 of IGF-2 (homologous to the autoantigen insulin B9-23) is presented to DQ8+ type 1 diabetic patients. Since subcutaneous and oral insulin does not exert any tolerogenic properties, IGF-2 and other thymus self-antigens related to type I diabetes (T1D) should be preferred to insulin for the design of novel specific antigen-based preventive approaches against T1D. [less ▲]

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See detailDendritic cell differentiation and immune tolerance to insulin-related peptides in Igf2-deficient mice
Hansenne, Isabelle ULg; Renard-Charlet, C.; Greimers, Roland ULg et al

in Journal of Immunology (Baltimore, Md. : 1950) (2006), 176(8), 4651-4657

There is some evidence that insulin-like growth factor 2 (IGF-2) may intervene in the control of T cell differentiation. To further study the immunoregulatory function of this growth factor, we analyzed ... [more ▼]

There is some evidence that insulin-like growth factor 2 (IGF-2) may intervene in the control of T cell differentiation. To further study the immunoregulatory function of this growth factor, we analyzed the immune system of Igf2(-/-) mice. Phenotypically, some immunological parameters such as lymphoid organ morphology and cellularity were unaltered in Igf2(-/-) mice, but an increase of CD8(+) cells and a decrease of B220(+) cells were observed in spleen. In vitro, the development of bone marrow-derived dendritic cells was affected by the absence of Igf2 expression. After maturation, a higher percentage of immature dendritic cells was observed in Igf2(-/-) population, together with a secondary decrease in allogenic T cell proliferation. Activation of T cells was also affected by the lack of expression of this growth factor. The profile of B cell response in mutant mice immunized with IGF-2 evidenced a T-dependent profile of anti-IGF-2 Abs that was absent in Igf2(+/+) mice. The influence of IGF-2 upon tolerance to insulin was also assessed in this model, and this showed that IGF-2 also intervenes in tolerance to insulin. The presence of a T-dependent response in Igf2-deficient mice should allow cloning of specific "forbidden" T CD4(+) lymphocytes directed against IGF-2, as well as further investigation of their possible pathogenic properties against insulin family. [less ▲]

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See detailDu nouveau à l'interface materno-foetale: rôle du couple hCG/récepteur LH-hCG dans l'implantation embryonnaire
PERRIER d'HAUTERIVE, Sophie ULg; Charlet, Jeanne de Chantal ULg; Dubois, Michel ULg et al

in Revue Médicale de Liège (2006), 61(10), 705-12

Implantation of the embryo into the maternal endometrium represents a unique biological process, combining an immunological (tolerance of an allograft) and biological (adhesion of two epitheliums) paradox ... [more ▼]

Implantation of the embryo into the maternal endometrium represents a unique biological process, combining an immunological (tolerance of an allograft) and biological (adhesion of two epitheliums) paradox. The success of implantation depends on a receptive endometrium, a functionally normal blastocyst and a synchronized cross-talk between embryonic and maternal tissues. Though sexual steroids control the process, a cascade of growth factors or cytokines are the prime paracrine mediators of the dialogue at the maternal-embryonic interface. HCG is one of the molecules most precociously produced by the embryo and is the most specific marker of its presence. HCG is a luteotropic factor which relays the inadequate support provided by the reduced rates of LH, but also influences the pregnancy on a paracrine mode by a local action on implantation process, probably by interacting with its receptor, the LH/hCG-R that we have evidenced on endometrial epithelium. We demonstrate that embryo actively participate into its implantation, tolerance and placentation. [less ▲]

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See detailAntiviral diabetes susceptibility gene
Geenen, Vincent ULg

in International Diabetes Monitor (2006), 18

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See detailProlonged viral RNA detection in blood and lymphoid tissues from Coxsackievirus B4 E2 orally-inoculated Swiss mice
Jaidane, H.; Gharbi, J.; Lobert, P. E. et al

in Microbiology and Immunology (2006), 50(12), 971-974

The spreading of viral RNA within Swiss Albino mice orally inoculated with coxsackievirus B4 E2 strain (CVB4 E2) was studied by using RT-PCR and semi-nested-RT-PCR methods. Viral RNA was detected in ... [more ▼]

The spreading of viral RNA within Swiss Albino mice orally inoculated with coxsackievirus B4 E2 strain (CVB4 E2) was studied by using RT-PCR and semi-nested-RT-PCR methods. Viral RNA was detected in various organs: pancreas, heart, small intestine, spleen, thymus, and blood at various post-infectious (p.i.) times ranging from 8 hr to 150 days. Our results show that (i) outbred mice can be infected with CVB4 E2 following an oral inoculation, which results in systemic spreading of viral RNA, (ii) CVB4 E2 infection can be associated with a prolonged detection of viral RNA in spleen, thymus and blood, up to 70 days p.i. and further in other organ tissues. [less ▲]

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See detailType 1 diabetes susceptibility loci from genome scans in multiplex families
Geenen, Vincent ULg

in International Diabetes Monitor (2006), 18

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See detailNovel perspectives in the pathogenesis of type 1 diabetes
Geenen, Vincent ULg

Conference (2005, November)

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See detailOxytocin receptor pattern of expression in primary lung cancer and in normal human lung
Pequeux, Christel ULg; Breton, C.; Hagelstein, M. T. et al

in Lung Cancer (2005), 50(2), 177-188

In order to assess if oxytocin- and vasopressin-induced mitogenic effects detected on small-cell lung carcinoma (SCLC) cell lines could be transposed on primary SCLC, the aim of the present work was to ... [more ▼]

In order to assess if oxytocin- and vasopressin-induced mitogenic effects detected on small-cell lung carcinoma (SCLC) cell lines could be transposed on primary SCLC, the aim of the present work was to identify mediators of these mitogenic actions on primary tumours samples. This was addressed on normal human lung tissue, on SCLC and on non-SCLC (NSCLC). Herein, we observe, in normal human lung, that OTR is colocalized with vascular endothelial cells of the lung and is not expressed by lung cells of epithelial nature. We detected mRNA amplification of V1aR, V2R and of a V2R variant. We observed that 86% of SCLC biopsies analyzed expressed at least the OTR and that 71% expressed the OTR, the V1aR and the V2R altogether. Comparatively, 50% of NSCLC biopsies tested expressed at least the OTR and 32% expressed the OTR, the V1aR and the V2R altogether. The occurrence of the V1bR/V3R is of 28 and 18% for SCLC and NSCLC, respectively. Nevertheless, for the SCLC biopsies analyzed in this study, V1bR/V3R expression correlates, in all cases, with the expression of all the other neurohypophysial peptide receptors. Our results suggest that neurohypophysial peptide antagonists may offer promise as a potential new therapeutic modality for the treatment of lung cancer expressing at least one of the neurhypophysial peptide receptor subtypes. (c) 2005 Elsevier Ireland Ltd. All rights reserved. [less ▲]

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See detailOntogenesis and functional aspects of oxytocin and vasopressin gene expression in the thymus network
Hansenne, Isabelle ULg; Rasier, G.; Pequeux, Christel ULg et al

in Journal of Neuroimmunology (2005), 158(1-2), 67-75

Ontogenesis of oxytocin (OT) and vasopressin (VP) gene expression and function were investigated in murine thymus. OT and VP transcripts were detected in the thymus on embryonic days 13 and 15 ... [more ▼]

Ontogenesis of oxytocin (OT) and vasopressin (VP) gene expression and function were investigated in murine thymus. OT and VP transcripts were detected in the thymus on embryonic days 13 and 15, respectively. Corresponding messenger RNAs were evidenced in thymic epithelial cells by in situ hybridization with a neurophysin probe. From all OT and VP receptors, only OTR was expressed by all T-cell subsets, while V1bR was found in double positive and single positive CD8 cells. In fetal thymic organ cultures, OTR antagonist d[DTyr(Et)(2), Thr(4)]OVT increased early apoptosis of CD8 cells, while V1bR antagonist (Sanofi SSR 149415) inhibited T-cell differentiation, and favored CD8 T-cell commitment. (C) 2004 Elsevier B.V. All rights reserved. [less ▲]

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