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MICRORNA-155 (MIR-155) INHIBIT T LYMPHOCYTE PRENYLATION TO PROTECT AGAINST ACUTE GRAFT VERSUS HOST DISEASE (AGVHD)
Author(s): ,
Xiaoxiao Wang
Affiliations:
Union Hospital, Tongji Medical College, Huazhong University of Science & Technology,WuHan,China
Linghui Xia
Affiliations:
Union Hospital, Tongji Medical College, Huazhong University of Science & Technology,WuHan,China
(Abstract release date: 05/17/18) EHA Library. Wang X. 06/16/18; 214528; S819
Xiaoxiao Wang
Xiaoxiao Wang
Contributions
Abstract

Abstract: S819

Type: Oral Presentation

Presentation during EHA23: On Saturday, June 16, 2018 from 11:45 - 12:00

Location: Room K1

Background
It is reported that farnesyl-transferase and geranylgeranyl-transferase inhibitors could help to reduce graft-versus-host (GVHD) disease significantly without having a negative impact on immune reconstitution. Previously, we have reported that miR-155 levels in T lymphocyte from peripheral blood of acut GVHD (aGVHD) patients and mice were significantly elevated and the inhibition of miR-155 can relieve the severe murine aGVHD. 

Aims
 we show a novel mechanism that inhibition of miR-155 protects against aGVHD via effects on prenylation of T cells.

Methods
TNF-α, which participates in the initiating events that culminate in aGVHD as well as amplifies the disease process once established. Therefore, TNF-α induced T cell injury was used to simulate the course of aGVHD in vitro. To assess the contribution of miR-155 to prenylation of human T lymphocyte, T lymphocyte from human peripheral blood mononuclear cells (PBMCs) was selected through negative selection using magnetic bead, which was effected for 48h with antagomir-155 and antagomir-NC before stimulated with TNF-α (100ng/ml) for 24h. To assess the contribution of miR-155 to prenylation in vivo, a well-established MHC mismatched bone marrow transplantation (BMT) model (C57BL/6 to BALB/c) was used to investigate the effect of deficiency of miR-155 on prenylation in vivo. 800 cGy X-rays irradiated BALB/c mice transplanted with 1×10BM cells and 2×107 spleen cells from C57BL/6 mice, were treated with antagomir-155 and antagomir-NC at a loading dose of 25 mg/kg on +7d, 5 mg/kg intravenously twice weekly up to +21d post-transplant. Mice T lymphocyte magnetically isolated from PBMCs. we examined expression of prenyltransferase of both human T lymphocyte and mice T lymphocyte by Realtime quantitative-PCR and western blotting. We evaluated the severity of aGVHD using a histopathology scoring system and the farnesyltransferase activity by immunohistochemistry.

Results
The results indicated TNF-α stimulated T cells to imitate aGVHD in vitro induced a higher expression of miR-155 (Figure1a,P<0.05), coincidentally, TNF-α stimulated T cells resulted a higher expression of farnesyltransferase(FT) subunits farnesyltransferase-α(FNTA)which is common to geranylgeranyltransferaseⅠ-α and farnesyltransferase-β(FNTB)mRNA (Figure1b) and protein levels(Figure3), similarly increased geranylgeranyltransferaseⅡ(GGTⅡ) subunits RABgeranylgeranyltransferase-α(RABGGTA) and RABgeranylgeranyltransferase-β(RABGGTB) mRNA expression(Figure1c). Intriguingly, the suppression of miR-155 could reverse this phenomenon, which not only restrained FNTA, FNTB mRNA and protein expression (Figure1b, P<0.01), but also decreased RABGGTA and RABGGTB (Figure1c, P<0.05) mRNA levels. Simultaneously, in aGVHD mice models, compared with control groups, aGVHD group caused higher expression of FNTA, FNTB, REBGGTA and RABGGTB, however, which exacerbation can be reversed by inhibition of miR-155 (Figure2a, b, P<0.05), all of this suggested that during the initiation and development of aGVHD, prenyltransferase and miR-155 levels were both increased, the suppression of miR-155 decreased th xpression of prenyltransferase in vivo and vitro. Next, we consistently discovered that the miR-155 deficient aGVHD mice which had a lower histopathology score of live(Figure3b) and small intestine(Figure3c) possessed of decreased farnesylated proteins and farnesyltransferase activity in spleen(Figure3a).

Conclusion
 this results confirmed that miR-155 simulate the role of farnesyl-transferase and geranylgeranyl-transferase inhibitors to relieve the effect of aGVHD.

Session topic: 22. Stem cell transplantation - Experimental

Keyword(s): Acute graft-versus-host disease

Abstract: S819

Type: Oral Presentation

Presentation during EHA23: On Saturday, June 16, 2018 from 11:45 - 12:00

Location: Room K1

Background
It is reported that farnesyl-transferase and geranylgeranyl-transferase inhibitors could help to reduce graft-versus-host (GVHD) disease significantly without having a negative impact on immune reconstitution. Previously, we have reported that miR-155 levels in T lymphocyte from peripheral blood of acut GVHD (aGVHD) patients and mice were significantly elevated and the inhibition of miR-155 can relieve the severe murine aGVHD. 

Aims
 we show a novel mechanism that inhibition of miR-155 protects against aGVHD via effects on prenylation of T cells.

Methods
TNF-α, which participates in the initiating events that culminate in aGVHD as well as amplifies the disease process once established. Therefore, TNF-α induced T cell injury was used to simulate the course of aGVHD in vitro. To assess the contribution of miR-155 to prenylation of human T lymphocyte, T lymphocyte from human peripheral blood mononuclear cells (PBMCs) was selected through negative selection using magnetic bead, which was effected for 48h with antagomir-155 and antagomir-NC before stimulated with TNF-α (100ng/ml) for 24h. To assess the contribution of miR-155 to prenylation in vivo, a well-established MHC mismatched bone marrow transplantation (BMT) model (C57BL/6 to BALB/c) was used to investigate the effect of deficiency of miR-155 on prenylation in vivo. 800 cGy X-rays irradiated BALB/c mice transplanted with 1×10BM cells and 2×107 spleen cells from C57BL/6 mice, were treated with antagomir-155 and antagomir-NC at a loading dose of 25 mg/kg on +7d, 5 mg/kg intravenously twice weekly up to +21d post-transplant. Mice T lymphocyte magnetically isolated from PBMCs. we examined expression of prenyltransferase of both human T lymphocyte and mice T lymphocyte by Realtime quantitative-PCR and western blotting. We evaluated the severity of aGVHD using a histopathology scoring system and the farnesyltransferase activity by immunohistochemistry.

Results
The results indicated TNF-α stimulated T cells to imitate aGVHD in vitro induced a higher expression of miR-155 (Figure1a,P<0.05), coincidentally, TNF-α stimulated T cells resulted a higher expression of farnesyltransferase(FT) subunits farnesyltransferase-α(FNTA)which is common to geranylgeranyltransferaseⅠ-α and farnesyltransferase-β(FNTB)mRNA (Figure1b) and protein levels(Figure3), similarly increased geranylgeranyltransferaseⅡ(GGTⅡ) subunits RABgeranylgeranyltransferase-α(RABGGTA) and RABgeranylgeranyltransferase-β(RABGGTB) mRNA expression(Figure1c). Intriguingly, the suppression of miR-155 could reverse this phenomenon, which not only restrained FNTA, FNTB mRNA and protein expression (Figure1b, P<0.01), but also decreased RABGGTA and RABGGTB (Figure1c, P<0.05) mRNA levels. Simultaneously, in aGVHD mice models, compared with control groups, aGVHD group caused higher expression of FNTA, FNTB, REBGGTA and RABGGTB, however, which exacerbation can be reversed by inhibition of miR-155 (Figure2a, b, P<0.05), all of this suggested that during the initiation and development of aGVHD, prenyltransferase and miR-155 levels were both increased, the suppression of miR-155 decreased th xpression of prenyltransferase in vivo and vitro. Next, we consistently discovered that the miR-155 deficient aGVHD mice which had a lower histopathology score of live(Figure3b) and small intestine(Figure3c) possessed of decreased farnesylated proteins and farnesyltransferase activity in spleen(Figure3a).

Conclusion
 this results confirmed that miR-155 simulate the role of farnesyl-transferase and geranylgeranyl-transferase inhibitors to relieve the effect of aGVHD.

Session topic: 22. Stem cell transplantation - Experimental

Keyword(s): Acute graft-versus-host disease

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