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See detailTh17 cells impact on xenogeneic graft-versus-host disease
Delens, Loïc ULg; SERVAIS, Sophie ULg; Ehx, Grégory ULg et al

Poster (2017, May 24)

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See detailAzacytidine prevents experimental xenogeneic graft-versus-host disease without abrogating graft-versus-leukemia effects
Ehx, Grégory ULg; Fransolet, Gilles ULg; De Leval, Laurence et al

in Oncoimmunology (2017)

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 ... [more ▼]

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 (Treg). Here, we investigated the impact of AZA on xenogeneic graft-versus-host disease (xGVHD) and graft-versus-leukemia effects in a humanized murine model of transplantation (human PBMCs-infused NSG mice), and described the impact of the drug on human T cells in vivo. We observed that AZA improved both survival and xGVHD scores. Further, AZA significantly decreased human T-cell proliferation as well as IFN-γ and TNF-α serum levels, and reduced the expression of GRANZYME B and PERFORIN 1 by cytotoxic T cells. In addition, AZA significantly increased Treg frequency through hypomethylation of FOXP3i1 as well as increased Treg proliferation. The later was subsequent to higher STAT5 signaling in Treg from AZA-treated mice, which resulted from higher IL-2 secretion by conventional T cells from AZA-treated mice itself secondary to demethylation of the IL-2 gene promoter by AZA. Importantly, Tregs harvested from AZA-treated mice were suppressive and stable over time since they persisted at high frequency in secondary transplant experiments. Finally, graft-versus-leukemia effects (assessed by growth inhibition of THP-1 cells, transfected to express the luciferase gene) were not abrogated by AZA. In summary, our data demonstrate that AZA prevents xGVHD without abrogating graft-versus-leukemia effects. These findings could serve of basis for further studies of GVHD prevention by AZA in acute myeloid leukemia patients offered an allogeneic transplantation. [less ▲]

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

Poster (2017, March 27)

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See detailImmunomodulatory effects of rapamycin in xenogeneic Graft versus Host Disease
Ehx, Grégory ULg; Hannon, Muriel ULg; DUBOIS, Sophie ULg et al

in Biology of Blood and Marrow Transplantation (2017, March), 23(3), 365366

Graft-versus-host disease (GVHD) remains a major cause of morbidity and mortality after allogeneic hematopoietic stem cell transplantation. Several studies have suggested 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. Several studies have suggested that rapamycin (RAPA), an mTOR inhibitor with immunosuppressive properties, may reduce GVHD severity and mortality, possibly by promoting regulatory T cells (Tregs). However, few data have been reported about the impact of this drug on overall T cell population. The present work aims at investigating the mechanisms by which RAPA impacts GVHD in a humanized mouse model of GVHD (NSG mice infused with human PBMCs). We observed that RAPA injections significantly reduced xenogeneic GVHD lethality and severity. RAPA dramatically reduced human cells chimerism in RAPA mice and increased 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-). Further, the differentiation of helper T cells (Th1, Th2 and Th17) was significantly decreased in treated mice. 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 suggest that RAPA ameliorates GVHD by lowering cytotoxic and effector CD4+ T cells frequency as well as promoting Tregs. [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 detailImpact des cellules Th17 sur la GVH xénogénique
Delens, Loïc ULg; SERVAIS, Sophie ULg; Ehx, Grégory ULg et al

Conference (2016, November 18)

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See detailAzacytidine prevents experimental xenogeneic graft-versus-host disease without abrogating graft-versus-leukemia effects
Ehx, Grégory ULg; Fransolet, Gilles ULg; de Leval, Laurence ULg et al

Conference (2016, November 18)

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 ... [more ▼]

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 (Treg). Here, we investigated the impact of AZA on xenogeneic graft-versus-host disease (xGVHD) and graft-versus-leukemia effects in a humanized murine model of transplantation (human PBMCs-infused NSG mice), and described the impact of the drug on human T cells in vivo. We observed that AZA improved both survival and xGVHD scores. Further, AZA significantly decreased human T-cell proliferation as well as IFN-γ and TNF-α serum levels, and reduced the expression of GRANZYME B and PERFORIN 1 by cytotoxic T cells. In addition, AZA significantly increased Treg frequency through hypomethylation of FOXP3i1 as well as increased Treg proliferation. The later was subsequent to higher STAT5 signaling in Treg from AZA-treated mice, which resulted from higher IL-2 secretion by conventional T cells from AZA-treated mice itself secondary to demethylation of the IL-2 gene promoter by AZA. Importantly, Tregs harvested from AZA-treated mice were suppressive and stable over time since they persisted at high frequency in secondary transplant experiments. Finally, graft-versus-leukemia effects (assessed by growth inhibition of THP-1 cells, transfected to express the luciferase gene) were not abrogated by AZA. In summary, our data demonstrate that AZA prevents xGVHD without abrogating graft-versus-leukemia effects. These findings could serve of basis for further studies of GVHD prevention by AZA in acute myeloid leukemia patients offered an allogeneic transplantation. [less ▲]

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

in Journal of Hematology & Oncology (2016), 9

Background <br />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 ... [more ▼]

Background <br />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. <br />Methods <br />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)). <br />Results <br />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. <br />Conclusions <br />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 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 detailGalectin-1 is involved in osteoclast biology
Muller, Joséphine ULg; Binsfeld, Marilène ULg; DUBOIS, Sophie ULg et al

Poster (2016, February 28)

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See detailImmunomodulatory effects of rapamycin in Graft versus Host Disease
Ehx, Grégory ULg; Hannon, Muriel ULg; Humblet-Baron, Stéphanie et al

Poster (2016, January 29)

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

Poster (2016, January 29)

Introduction: Graft-versus-host disease (GVHD) remains a major complication of allogeneic hematopoietic stem cell transplantation (HSCT). Following allo-transplantation, 60% of the patients experience ... [more ▼]

Introduction: Graft-versus-host disease (GVHD) remains a major complication of allogeneic hematopoietic stem cell transplantation (HSCT). Following allo-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) or Decitabine (DAC) can demethylate the master transcription factor of Treg (FoxP3), thus promoting Treg differentiation from Tconvs. This work investigates the impact of AZA and DAC in a murine model of sclerodermic chronic GVHD. Methods: 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 0.5 or 2 mg/kg of AZA or 0.75 mg/kg of DAC every 48h 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. Results: Mice treated with AZA 0.5 mg/kg (n=14) or 2 mg/kg (n=17) or DAC 0.75 mg/kg (n=5) had lower clinical scores of GVHD compared to control (n=15). FACS analyses showed a higher proportion of Treg in the blood of AZA 0.5 or 2 mg/kg or DAC 0.75 mg/kg mice than in control at day 35. Results also showed a decreased number of Tconv and CD8 in AZA and DAC treated mice while proliferation of these cells expressing Ki67 was lower during AZA/DAC treatment but higher after discontinuation. Histological analyses showed less skin fibrosis in mice treated with 2 mg/kg of AZA. Finally, analyses of the blood components demonstrated that AZA mice were leuco- and lymphopenic as compared to control at day 21 and 35. Conclusion : AZA and DAC prevented sclerodermic GVHD in this murine model. [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 detailGalectin-1 is involved in osteoclast biology
Muller, Joséphine ULg; Binsfeld, Marilène; DUBOIS, Sophie ULg et al

Poster (2016)

Detailed reference viewed: 13 (3 ULg)