References of "Ehx, Grégory"
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See detailLimited Impact of Imatinib in a Murine Model of Sclerodermatouc Chronic Graft-versus-Host Disease
Belle, Ludovic; Fransolet, Gilles ULg; Somja, Joan ULg et al

in PLoS ONE (2016)

Background Sclerodermatous chronic Graft-versus-Host Disease (scl-cGVHD) is one of the most severe form of cGVHD. The Platelet-derived Grotwth Factor (PDGF) and the Transforming Growth Factor-β (TGF-β ... [more ▼]

Background Sclerodermatous chronic Graft-versus-Host Disease (scl-cGVHD) is one of the most severe form of cGVHD. The Platelet-derived Grotwth Factor (PDGF) and the Transforming Growth Factor-β (TGF-β) play a significant role in the fibrosing process occurring in scl-cGVHD. This prompted us to assess the impact of the PDGF-r and c-Abl tyrosine kinase inhibitor imatinib on scl-cGVHD. Methods To assess the impact of imatinib on T cell subset proliferation in vivo, Balb/cJ recipient mice were lethally (7 Gy) irradiated and then injected with 10x106 bone marrow cells from B10.D2 mice on day 0. Fourteen days later, 70x106 carboxyfluorescein succinimidyl ester (CFSE)- labeled splenocytes from B10.D2 mice were infused and imatinib or sterile water was administered for 5 days. To induce severe scl-cGVHD, Balb/cJ mice were injected i.v. with 10.106 bone marrow cells and 70.106 splenocytes from B10.D2 donor mice after 7 Gy irradiation. Mice were then given sterile water or imatinib from day +7 after transplantation to the end of the experiment (day +52). Results Imatinib decreased the proliferation of total T cells (P = 0.02), CD8+ T cells (P = 0.01), and of regulatory T cells (Tregs) (P = 0.02) in the spleen. In the severe scl-cGVHD model, imatinib- treated mice had significantly lower levels of PDGF-r phosphorylation than control mice on day 29 after transplantation (P = 0.008). However, scl-cGVHD scores were similar between vehicle- and imatinib-treated mice during the whole experiment, while there was a suggestion for less weight loss in imatinib-treated mice that reached statistical significance at day +52 following transplantation (P = 0.02). [less ▲]

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See detailXenogeneic graft-versus-host disease: Impact of Th17 cells.
Delens, Loïc ULg; SERVAIS, Sophie ULg; Vrancken, Louise et al

Poster (2016, December 08)

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See detailLimited impact of imatinib in a murine model of sclerodermatous chronic graft-versus-host disease (scl-cGVHD)
Fransolet, Gilles ULg; Belle, Ludovic; SOMJA, Joan ULg et al

Conference (2016, December 08)

- Introduction: Graft-versus-host disease (GVHD) remains one of the major complications following haematopoietic stem cell transplantation (HSCT). Approximately 15% of the patients with chronic GVHD ... [more ▼]

- Introduction: Graft-versus-host disease (GVHD) remains one of the major complications following haematopoietic stem cell transplantation (HSCT). Approximately 15% of the patients with chronic GVHD develop the sclerodermatous form of the disease characterized by multiple organ fibrosis and loss of skin elasticity. Several studies have shown the potential benefits of imatinib, a tyrosine kinase inhibitor (TKI), as a treatment of fibrosis in cGVHD due to its ability to inhibit simultaneously PDGF-R and c-Abl pathways which are both involved in fibrosis mechanisms. - Aims: Some early-phase clinical studies have assessed the impact of TKIs in patients with steroid-refractory cGVHD. Unfortunately, these studies yielded to conflicting results underlying the importance of re-assessing the impact of imatinib in scl-cGVHD pre-clinical models. This work investigates the possible benefits of imatinib on fibrosis in a murine model of sclerodermatous chronic GVHD (scl-cGVHD). - Methods and results: Lethally irradiated Balb/cJ mice (7 Gy TBI) were injected i.v. with 1.106 or 10.106 bone marrow cells and 2.106 or 70.106 splenocytes from B10.D2 donnor mice (Moderate and Classical scl-cGVHD models respectively). Mice were then treated with sterile water or imatinib (150 mg/kg/day) by oral gavage from day +7 to day +52 following transplantation. cGVHD severity was assessed three times/week with a scoring system encompassing 5 criteria (mice posture, weight loss, activity, hair loss, skin integrity ; 0-1-2 point(s)/criteria). Skin biopsies were performed on day +29 following transplantation to assess phosphorylation of c-Abl (TGF-β pathway) and PDGF receptor. Our results show that imatinib failed to prevent/improve GVHD with a similar evolution of the GVHD severity with no differences between groups (neither in moderate cGVHD model, nor in the classical cGVHD model). Mice weight loss during the experiments was also comparable between groups in both models of cGVHD. In the classical model, histological analyses indicate a significant reduction of the phosphorylation level of the PDGR receptor (p = 0.0079). In vivo cell proliferation assay with CFSE were also performed and showed a reduced proliferation of T cells and subsets (CD4, CD8 and Tregs) in spleen, lymph nodes, bone marrow and blood after imatinib treatment. Finally, FACS analyses performed on days +21 and +35 after transplantation did not show any differences in the absolute T-cell counts. - Conclusions: Although we have observed a decreased phosphorylation level of PDGR receptor and less proliferation of T cells and subsets in vivo, imatinib failed to alleviate scl-cGVHD both in moderate and classical murine models of scl-cGVHD. [less ▲]

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See detailLimited impact of imatinib in a murine model of sclerodermic chronic graft-versus-host disease
Belle, Ludovic; Fransolet, Gilles ULg; SOMJA, Joan ULg et al

Poster (2016, November 17)

Background: Graft-versus-host disease (GVHD) remains one of the major complications following haematopoietic stem cell transplantation (HSCT). Approximately 15% of the patients with chronic GVHD develop ... [more ▼]

Background: Graft-versus-host disease (GVHD) remains one of the major complications following haematopoietic stem cell transplantation (HSCT). Approximately 15% of the patients with chronic GVHD develop the sclerodermatous form of the disease characterized by multiple organ fibrosis and loss of skin elasticity. Several studies have shown the potential benefits of imatinib, a tyrosine kinase inhibitor, as a treatment of fibrosis in cGVHD due to its ability to inhibit simultaneously PDGF-R and c-Abl pathways which are both involved in fibrosis mechanisms. This work investigates the possible benefits of imatinib on fibrosis in a murine model of sclerodermatous chronic GVHD (sclcGVHD). Methods: Lethally irradiated Balb/cJ mice (7 Gy TBI) were injected i.v. with 10.106 bone marrow cells and 70.106 splenocytes from B10.D2 donnor mice. Mice were then treated with sterile water or imatinib (150 mg/kg/day) by oral gavage from day +7 to day +52 following transplantation. GVHD severity was assessed three times/week with a scoring system encompassing 5 criteria (mice posture, weight loss, activity, hair loss, skin integrity ; 0-1-2 point(s)/criteria). Results: Our results show that imatinib failed to prevent/improve GVHD with a similar evolution of the GVHD severity with no differences between groups. Histological analyses indicate a significant reduction of the phosphorylation level of the PDGR receptor (p = 0,033) and a trend to a decreased level of phosphorylated c-Abl (p = 0,1854). In vivo cell proliferation assay with CFSE were also performed and showed a reduced proliferation of T cells and subsets (CD4, CD8 and Tregs) in spleen, lymph nodes, bone marrow and blood after imatinib treatment. Finally, FACS analyses performed on days +21 and +35 after transplantation did not show any differences in the absolute T-cell counts. Conclusion: Although we have observed a decreased phosphorylation level of PDGR receptor and less proliferation of T cells and subsets in vivo, imatinib failed to alleviate scl-cGVHD in a murine model of severe scl-cGVHD. [less ▲]

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See detailAzacytidine mitigates experimental sclerodermic graft-versus-host disease
Fransolet, Gilles ULg; Ehx, Grégory ULg; SOMJA, Joan ULg et al

in Journal of Hematology & Oncology (2016)

Background Previous studies have demonstrated that regulatory T cells (Tregs) play a protective role in the pathogenesis of chronic graft-versus-host disease (cGVHD). Tregs constitutively express the gene ... [more ▼]

Background Previous studies have demonstrated that regulatory T cells (Tregs) play a protective role in the pathogenesis of chronic graft-versus-host disease (cGVHD). Tregs constitutively express the gene of the transcription factor Foxp3 whose CNS2 region is heavily methylated in conventional CD4+ T cells (CD4+Tconvs) but demethylated in Tregs. Methods Here, we assessed the impact of azacytidine (AZA) on cGVHD in a well-established murine model of sclerodermic cGVHD (B10.D2 (H-2d) → BALB/cJ (H-2d)). Results The administration of AZA every 48 h from day +10 to day +30 at the dose of 0.5 mg/kg or 2 mg/kg mitigated chronic GVHD. Further, AZA-treated mice exhibited higher blood and thymic Treg frequencies on day +35, as well as higher demethylation levels of the Foxp3 enhancer and the IL-2 promoter in splenocytes at day +52. Interestingly, Tregs from AZA-treated mice expressed more frequently the activation marker CD103 on day +52. AZA-treated mice had also lower counts of CD4+Tconvs and CD8+ T cells from day +21 to day +35 after transplantation, as well as a lower proportion of CD4+Tconvs expressing the Ki67 antigen on day +21 demonstrating an anti-proliferating effect of the drug on T cells. Conclusions Our results indicate that AZA prevented sclerodermic cGVHD in a well-established murine model of cGVHD. These data might serve as the basis for a pilot study of AZA administration for cGVHD prevention in patients at high risk for cGVHD. [less ▲]

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See detailNovel approaches for preventing acute graftversus- host disease after allogeneic hematopoietic stem cell transplantation
SERVAIS, Sophie ULg; BEGUIN, Yves ULg; Delens, Loïc ULg et al

in Expert Opinion on Investigational Drugs (2016)

Introduction Allogeneic hematopoietic stem cell transplantation (alloHSCT) offers potential curative treatment for a wide range of malignant and nonmalignant hematological disorders. However, its success ... [more ▼]

Introduction Allogeneic hematopoietic stem cell transplantation (alloHSCT) offers potential curative treatment for a wide range of malignant and nonmalignant hematological disorders. However, its success may be limited by post-transplant acute graft-versus-host disease (aGVHD), a systemic syndrome in which donor’s immune cells attack healthy tissues in the immunocompromised host. aGVHD is one of the main causes of morbidity and mortality after alloHSCT. Despite standard GVHD prophylaxis regimens, aGVHD still develops in approximately 40–60% of alloHSCT recipients. Areas covered In this review, after a brief summary of current knowledge on the pathogenesis of aGVHD, the authors review the current combination of a calcineurin inhibitor with an antimetabolite with or without added anti-thymocyte globulin (ATG) and emerging strategies for GVHD prevention. Expert opinion A new understanding of the involvement of cytokines, intracellular signaling pathways, epigenetics and immunoregulatory cells in GVHD pathogenesis will lead to new standards for aGVHD prophylaxis allowing better prevention of severe aGVHD without affecting graft-versus-tumor effects. [less ▲]

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See detailAzacytidine Enhances Regulatory T-Cells In Vivo and Prevents Experimental Xenogeneic Graft-Versus-Host Disease
Ehx, Grégory ULg; Fransolet, Gilles ULg; de Leval, Laurence ULg et al

in Biology of Blood and Marrow Transplantation (2016, March), 22(3), 393

Background. The demethylating agent 5-azacytidine (AZA) has proven its efficacy as treatment for myelodysplastic syndrome and acute myeloid leukemia. In addition, AZA can demethylate FOXP3 intron 1 ... [more ▼]

Background. The demethylating agent 5-azacytidine (AZA) has proven its efficacy as treatment for myelodysplastic syndrome and acute myeloid leukemia. In addition, AZA can demethylate FOXP3 intron 1 (FOXP3i1) leading to the generation of regulatory T cells (Tregs). Objective. We investigated the impact of AZA on xenogeneic graft-versus-host disease (xGVHD) in a humanized murine model of transplantation, and described the impact of the drug on human T cells in vivo. Methods. In order to induce xGVHD, human peripheral blood mononuclear cells (huPBMC) were administered intravenously in NOD-scid IL-2Rγnull (NSG) mice. Results. AZA successfully improved both survival (p<0.0001) and xGVHD scores (p<0.0001). Further, AZA significantly decreased human T-cell proliferation as well as INF-γ and TNF-α serum levels, and reduced the expression of GRANZYME B and PERFORIN 1 by cytotoxic T cells. In addition, AZA administration significantly increased the function, proliferation and frequency of Tregs through demethylation of FOXP3i1 and higher secretion of IL-2 by conventional T cells due to IL2 gene promoter site 1 demethylation. Interestingly, among AZA-treated mice surviving the acute phase of xGVHD, there was an inverse correlation between the presence of Tregs and signs of chronic GVHD. Finally, Tregs harvested from the spleen of AZA-treated mice were suppressive and stable over time since they persisted at high frequency in secondary transplant experiments. Conclusion. These findings emphasize a potential role for AZA as prevention or treatment of GVHD and other autoimmune diseases. [less ▲]

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See detailSalt but not glucocorticoïds enhances Th17 differentiation from naïve T cells in vitro
Delens, Loïc ULg; SERVAIS, Sophie ULg; Vrancken, Louise et al

Poster (2016, January 29)

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See detailL'Azacytidine comme traitement de la maladie du greffon contre l'hôte de type chronique sclérodermique expérimentale.
Fransolet, Gilles ULg; Ehx, Grégory ULg; SOMJA, Joan ULg et al

Conference (2015, November 19)

Introduction: Graft-versus-host disease (GVHD) has remained a major complication of allogeneic hematopoietic stem cell transplantation (HSCT) for the last decades. Following unmanipulated peripheral-blood ... [more ▼]

Introduction: Graft-versus-host disease (GVHD) has remained a major complication of allogeneic hematopoietic stem cell transplantation (HSCT) for the last decades. Following unmanipulated peripheral-blood stem cell transplantation, 60% of the patients experience chronic GVHD while approximately 15% of them develop a sclerodermic form of chronic GVHD characterized by multiple organ fibrosis and loss of skin elasticity. Regulatory T cells (Tregs) play a pivotal protective role in the pathogenesis of chronic GVHD by inhibiting alloreactive conventional T cells (Tconvs). Several studies have shown that hypomethylating agents such as azacytidine (Aza) can demethylate the master transcription factor of Treg (Forkhead box protein 3 factor, FoxP3), thus promoting Treg differentiation from Tconvs. This work investigates the impact of Aza in a classical murine model of sclerodermic chronic GVHD (B10.D2  BALB/cJ). Methods: In vitro analyses have been performed to determine the impact of Aza on collagen production. NIH-3T3 fibroblastic cells were plated and stimulated with 50 ng of PDGF or 10 ng of TGF-beta. Cells were then cultured with various concentrations of Aza for 48 hours. After culture, cells were stained with Sirius Red before quantification of collagen amount by absorbance at 490 nm. For in vivo experiments, lethally irradiated (7 Gy) BALB/cJ recipient mice were injected with 107 bone marrow cells + 7.107splenocytes from B10.D2 donor mice to induce scl-cGVHD. Recipients were injected with either 0,5 or 2 mg/kg of Aza every 48 hours from day 10 to 30 following transplantation. GVHD was scored using a five criteria scale (weight loss, activity, fibrosis, hair loss and mice posture; 0-1-2 points/criteria). Mice were sacrificed at a score of 8/10 (or > 20% weight loss) or at day 52 after transplantation (end of experiment). Results: Concerning in vitro analyses, results suggest a decreased production of collagen at higher concentration of Aza with both stimulations (seen by a gradual diminution of absorbance). For in vivo experiments, mice treated with Aza 0.5 mg/kg (n = 14) or 2 mg/kg (n = 25) had significant lower clinical scores of GVHD compared to control ones (n = 23) after treatment. FACS analysis showed a higher proportion of Treg among CD4+ T cells in the blood of Aza 2 mg/kg mice than in control mice at day 35 following transplantation (P = 0.047), as well as a higher percentage of Tregs expressing the KI67 proliferative marker on the same time point (P = 0.0005). Finally, analyses of the cellular blood components with Cell-dyn demonstrated that Aza 2 mg/kg treated mice were significantly lymphopenic as compared to control mice at day 35 after transplantation (P = 0.05). Conclusion : Aza prevented sclerodermic GVHD in this classical murine model of chronic GVHD. [less ▲]

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See detailImmune Recovery after Allogeneic Hematopoietic Stem Cell Transplantation following Flu-TBI versus TLI-ATG Conditioning
HANNON, Muriel ULg; BEGUIN, Yves ULg; Ehx, Grégory ULg et al

in Clinical Cancer Research : An Official Journal of the American Association for Cancer Research (2015), 21(14), 3131-9

Purpose: A conditioning regimen for allogeneic hematopoietic cell transplantation (HCT) combining total lymphoid irradiation (TLI) plus anti-thymocyte globulin (ATG) has been develop to induce graft ... [more ▼]

Purpose: A conditioning regimen for allogeneic hematopoietic cell transplantation (HCT) combining total lymphoid irradiation (TLI) plus anti-thymocyte globulin (ATG) has been develop to induce graft-versus-tumor effects without graft-versus-host disease (GVHD). Experimental Design: We compared immune recovery in 53 patients included in a phase II randomized study comparing nonmyeloablative HCT following either fludarabine plus 2 Gy total body irradiation (TBI arm, n=28) or 8 Gy TLI plus anti-thymocyte globulin (TLI arm, n=25). Results: In comparison to TBI patients, TLI patients had a similarly low 6-month incidence of grade II-IV acute GVHD, a lower incidence of moderate/severe chronic GVHD (P=0.02), a higher incidence of CMV reactivation (P<0.001), and a higher incidence of relapse (P=0.01). While recovery of total CD8+ T cells was similar in the two groups, with median CD8+ T cell counts reaching the normal values 40-60 days after allo-HCT, TLI patients had lower percentages of naïve CD8 T cells. Median CD4+ T cell counts did not reach the lower limit of normal values the first year after allo-HCT in the two groups. Further, CD4+ T cell counts were significantly lower in TLI than in TBI patients the first 6 months after transplantation. Interestingly, while median absolute regulatory T cell (Treg) counts were comparable in TBI and TLI patients, Treg/naïve CD4+ T cell ratios were significantly higher in TLI than in TBI patients the 2 first years after transplantation. Conclusions: Immune recovery differs substantially between these two conditioning regimens possibly explaining the different clinical outcomes observed (NCT00603954). [less ▲]

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See detailAzacytidine prevents experimental sclerodermic chronic graft-versus-host disease
Fransolet, Gilles ULg; Ehx, Grégory ULg; SOMJA, Joan ULg et al

Poster (2015, January 30)

Introduction: Graft-versus-host disease (GVHD) remains one major complication of allogeneic hematopoietic stem cell transplantation (HSCT). Following unmanipulated peripheral-blood stem cell ... [more ▼]

Introduction: Graft-versus-host disease (GVHD) remains one major complication of allogeneic hematopoietic stem cell transplantation (HSCT). Following unmanipulated peripheral-blood stem cell transplantation, 60% of the patients experience chronic GVHD while approximately 15% of them develop a sclerodermic form of chronic GVHD characterized by multiple organ fibrosis and loss of skin elasticity. Regulatory T cells (Tregs) play a pivotal role in the pathology of chronic GVHD by inhibiting alloreactive conventional T cells. Several studies have shown the hypomethylating agent Azacytidine (Aza) can demethylate the master transcription factor of Treg (Forkhead box protein 3 factor, FoxP3), thus promoting Treg differentiation of conventional T cells. This work investigates the impact of Aza in a classical murine model of sclerodermic chronic GVHD (B10.D2  BALB/cJ). Methods: Lethally irradiated BALB/cJ recipient mice were injected with 107 bone marrow cells + 7.107splenocytes from B10.D2 donor mice. Recipients were treated with subcutaneous injections of Aza at the dose of 0,5 or 2 mg/kg every two days from day 10 to 30 following transplantation. Mice GVHD was evaluated with five criteria (weight loss, activity, fibrosis, hair loss and mice posture; 0-1-2 points/criteria). Mice were sacrificed at a score of 8/10 (or > 20% weight loss). Results: Mice treated with Aza 0.5 mg/kg (n = 14) or 2 mg/kg (n = 17) had significant lower clinical scores compared to control ones (n = 15) after treatment. FACS analysis showed a higher proportion of Treg among CD4+ T cells in the blood of Aza 2 mg/kg mice than in control mice (P = 0.047), as well as a higher percentage of Tregs expressing the KI67 proliferative marker on the same day (P = 0.0005). Finally, analyses of the cellular blood components with Cell-dyn demonstrated that Aza 2 mg/kg treated mice were significantly lymphopenic as compared to control mice (P = 0.05). Conclusion : Aza prevented sclerodermic GVHD in this classical murine model of chronic GVHD. [less ▲]

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See detailAzacytidine augments regulatory T cells and prevents experimental xenogeneic graft-versus-host disease.
Ehx, Grégory ULg

Conference (2015, January 30)

The demethylating agent 5-azacytidine (AZA) has proven its efficiency in myeloid malignancies treatment. Recently, several studies have shown that AZA also presents an immunomodulatory activity, mainly ... [more ▼]

The demethylating agent 5-azacytidine (AZA) has proven its efficiency in myeloid malignancies treatment. Recently, several studies have shown that AZA also presents an immunomodulatory activity, mainly through the induction of regulatory T cells (Treg) differentiation from conventional T cells. Treg promotion is a promising treatment option for graft-versus-host disease (GVHD) following hematopoietic stem cell transplantation. In this way, AZA has been shown to reduce GVHD in mouse-to-mouse transplantation models. However, the impact of AZA on human GVHD remains elusive as well as its effects on human Treg and on the other T cell subsets in vivo. Here we report AZA impact on GVHD in a xeno-transplantation model of the disease and describe the overall effects of the drug on human T cells in vivo. When administered to NSG mice receiving 2.107 human PBMC intravenously, AZA successfully ameliorated both survival (p < 0.001) and GVHD score. Flow cytometry analyses showed that this improvement may be mediated through an anti-proliferative effect of AZA on human T cells while these cells presented an increased activation state. We also observed a significant decrease of Th1 and 2 differentiation, assessed by RT-qPCR and cytokines secretion assays, and a reduced production of granzyme B and perforin 1 by cytotoxic T cells. As expected, AZA dramatically augmented Treg frequency while we could also observe a promotion of their IL-2 mediated proliferation over conventional T cells. Interestingly, Th17 frequency was not affected by AZA, therefore increasing the balance Treg/Th17. Finally our data suggest that AZA-induced Treg may have an improved suppressive activity and present long-term stability in vivo. Altogether our findings suggest that AZA may be a promising treatment option for GVHD in the clinical setting. [less ▲]

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See detailValidation of a multicolor staining to monitor phosphoSTAT5 levels in regulatory T-cell subsets
Ehx, Grégory ULg; Hannon, Muriel ULg; BEGUIN, Yves ULg et al

in Oncotarget (2015)

BACKGROUND: Regulatory T cells (Tregs) are key players in immune tolerance. They express the transcription factor FOXP3 and are dependent of the STAT5 signaling for their homeostasis. So far, the study of ... [more ▼]

BACKGROUND: Regulatory T cells (Tregs) are key players in immune tolerance. They express the transcription factor FOXP3 and are dependent of the STAT5 signaling for their homeostasis. So far, the study of phosphorylated epitopes by flow cytometry required treating the cells with methanol, which is harmful for several epitopes. METHODS: Here we assessed whether the PerFix EXPOSE reagent kit (PFE) (Beckman Coulter) allowed monitoring the phosphorylation level of STAT5 in Treg subpopulations together with complex immunophenotyping. Results observed with the PFE kit were compared to those observed without cell permeabilization for surface markers, with paraformaldehyde permeabilization for non-phosphorylated intracellular epitopes, and with methanol-based permeabilization for phosphoSTAT5 staining. RESULTS: In human PBMCs, the PFE kit allowed the detection of surface antigens, FOXP3, KI67 and phosphoSTAT5 in similar proportions to what was observed without permeabilization (for surface antigens), or with PFA or methanol permeabilizations for FOXP3/KI67 and phosphoSTAT5, respectively. Comparable observations were made with murine splenocytes. Further, the PFE kit allowed determining the response of different human and murine Treg subsets to IL-2. It also allowed demonstrating that human Treg subsets with the highest levels of phosphoSTAT5 had also the highest suppressive activity in vitro, and that anti-thymocyte glogulin (ATG) induced Treg independently of the STAT5 pathway, both in vitro and in vivo. CONCLUSIONS: We have validated a multicolor staining method that allows monitoring phosphoSTAT5 levels in Treg subsets. This staining could be useful to monitor responses of various Treg subsets to IL-2 therapy. [less ▲]

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See detailLiver proteomic response to hypertriglyceridemia in human-apolipoprotein C-III transgenic mice at cellular and mitochondrial compartment levels
Ehx, Grégory ULg; Gerin, Stéphanie ULg; Mathy, Grégory et al

in Lipids in Health and Disease (2014), 13

Background: Hypertriglyceridemia (HTG) is defined as a triglyceride (TG) plasma level exceeding 150 mg/dl and is tightly associated with atherosclerosis, metabolic syndrome, obesity, diabetes and acute ... [more ▼]

Background: Hypertriglyceridemia (HTG) is defined as a triglyceride (TG) plasma level exceeding 150 mg/dl and is tightly associated with atherosclerosis, metabolic syndrome, obesity, diabetes and acute pancreatitis. The present study was undertaken to investigate the impact of hypertriglyceridemia on the mitochondrial, sub-mitochondrial and cellular proteomes in the hepatocytes of a hypertriglyceridemic transgenic mouse model overexpressing the human apolipoproteinC-III. Methods: Quantitative comparative proteomics (2D-DIGE) was carried out in both “low-expressor” (LE) and “high-expressor” (HE) mice, respectively exhibiting moderate and severe HTG, to characterize the effect of the TG plasma level on the proteomic response. Results: The mitoproteome analysis revealed the occurrence of a large-scale adaptation in transgenic mice consisting of a general down-regulation of matricial proteins and up-regulation of inner membrane proteins. Remarkably, the magnitude of these proteomic changes appears to strongly depend on the TG plasma level. Altogether, our different analyses indicate that, in HE mice, the capacity of several metabolic pathways is altered to promote the availability of acetyl-CoA, glycerol-3-phosphate, ATP and NADPH for de novo TG biosynthesis. The up-regulation of several cytosolic ROS detoxifying enzymes also tend to confirm that the cytoplasm of HTG mice is subjected to oxidative stress as previously stated. The up-regulation of cytosolic ferritin indicates that iron over-accumulation could take place in the cytosol of HE mice hepatocytes and contribute to (i) enhance oxidative stress and (ii) promote cellular proliferation. Conclusions: The present analyses demonstrate that important TG dose-responsive metabolic adaptations are set up in human apolipoproteinC-III-overexpressing mice. Our results indicate that these adaptations could support the higher TG production rates which have been previously reported in this HTG model, and also suggest that cytosolic oxidative stress may result from FFA over-accumulation, iron overload and enhanced activity of some ROS-producing catabolic enzymes. [less ▲]

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See detailXenogeneic GVHD in NSG mice: focus on rapamycin
Ehx, Grégory ULg

Conference (2014, April 11)

Detailed reference viewed: 36 (8 ULg)
See detailImmunomodulatory effects of Rapamycin in xenogeneic GVHD
Ehx, Grégory ULg

Poster (2014, January 31)

Graft-versus-host disease (GVHD) remains a major cause of morbidity and mortality after allogeneic hematopoietic stem cell transplantation (HSCT). Several studies have shown that rapamycin (RAPA), an mTOR ... [more ▼]

Graft-versus-host disease (GVHD) remains a major cause of morbidity and mortality after allogeneic hematopoietic stem cell transplantation (HSCT). Several studies have shown that rapamycin (RAPA), an mTOR inhibitor with immunosuppressive properties, may reduce GVHD severity and mortality, notably by favoring regulatory T cells (Tregs) proliferation in vivo and in vitro. However, very few data have been reported about the global impact of this drug on the immune system in the context of GVHD. The present work investigates the cellular mechanisms by which RAPA delays death from xenogeneic GVHD induced by peripheral blood mononuclear cells infusion in NSG mice. Our results show that RAPA injections significantly delay death from xenogeneic GVHD and reduce disease severity. Flow cytometric analyses highlighted a strong reduction of human cells chimerism in mice together with higher CD4+/CD8+ T cells balance due to a lower proliferation of CD8+ T cells. In addition, the frequencies of naive CD4+ and CD8+ T cells were higher and the CD4+ T cells showed a reduced effector phenotype (CD45RO+CD27-). Tregs were positively affected as RAPA up-regulated their expression of Bcl-2 and Ki67 as well as their STAT5 phosphorylation level, leading to higher Treg frequency in treated mice. Altogether these data demonstrate that RAPA delays xenogeneic GVHD by lowering human chimerism and effector CD4+ frequency as well as promoting Tregs. [less ▲]

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