ACR Meeting Abstracts

ACR Meeting Abstracts

Abstract Number: 1783

TNFα Influences RasGRP1 and RasGRP3 Expression Levels in PBMC, B and T Cells

Marie-Laure Potier1, Martine Hiron1, Clément Guillou1, Céline Derambure2, Olivier Boyer3, Xavier Le Loët4, Olivier Vittecoq5 and Thierry Lequerré6, 1Inserm 905 & Institute for Biomedical Research, University of Rouen, Rouen, France, 2Inserm 905 & Institute for Biomedical Research, University of Rouen, Rouen, France, Rouen, France, 3Immunology, Inserm 905, Institute for Biomedical research, University of Rouen, Rouen, France, 4Rheumatology Department, Department of Rheumatology, Rouen University Hospital & Inserm 905, Institute for Biomedical Research, University of Rouen, Rouen Cedex, France, 5Rheumatology, Department of Rheumatology, Rouen University Hospital & Inserm 905, Institute for Biomedical Research, University of Rouen, Rouen Cedex, France, 6Rheumatology Department & Inserm 905, Department of Rheumatology, Rouen University Hospital & Inserm 905, Institute for Biomedical Research, University of Rouen, Rouen Cedex, France

Meeting: 2012 ACR/ARHP Annual Meeting

Keywords: , , ,

Session Information

Title: Cytokines, Mediators, and Gene Regulation

Session Type: Abstract Submissions (ACR)

Background/Purpose: Rheumatoid arthritis (RA) is the most common inflammatory arthritis. B and T lymphocytes play a central role in the pathophysiology of RA. RasGRP is a member of the CDC25 family of Ras guanyl nucleotide exchange factors. RasGRP1 is expressed in T and B cells whereas RasGRP3 is only expressed in B cells. In previous studies, we have shown that RasGRP3expression level significantly decreased in Peripheral blood mononuclear cells (PBMC) from RA patients responders to adalimumab after 3 months, leading to the question of TNFα involvement in pathways including RasGRP1 and RasGRP3. Objectives : To study TNFα effect on RasGRP1 and RasGRP3 expression levels in vitro.

Methods: We measured by qRT-PCR, RasGRP1 and RasGRP3 expression levels, i) in PBMC from 3 healthy controls (HC), ii) in negative selected B and T cells from PBMC isolated from 3 buffy coat. In each condition, cells were cultured with or without BCR or TCR stimulation for 4 days and TNFα was added for 24 or 48 hours. Immunofluorescence staining was performed to check the cell purity and B and T cells stimulation by flow cytometry. Moreover, IL-2 production was measured by ELISA in T-cells before and after TNFα stimulation. In addition, TNFα effects on cell proliferation were evaluated by [3H] thymidine incorporation by the B and T cells.

Results: In B cells, TNFα induced an increase of RasGRP1 (p<0.001) and RasGRP3 (p<0.001) expression levels in absence of BCR stimulation. In the same way, in T cells, TNFα induced an increase of RasGRP1 (p<0.001) and RasGRP3 (p<0.001) expression levels in absence of TCR stimulation. Furthermore, TNFα induced a significantly increased of IL-2 production (p<0.05) in unstimulated T-cells. However, TNFα have no effects on B and T cells proliferation

Conclusion: This study suggests the RasGRP1 and RasGRP3 regulation by TNFα, independently of B and T cells stimulation. The increasing of RasGRP3 and RasGRP1 in B and T cells specifically via TNFα binding on its receptors could promote the activation and proliferation of B and T cells using another signaling pathway than BCR and TCR. This second pathway could explain the maintenance of B and T cells activation by an independent antigen pathway.

Disclosure:

M. L. Potier,
None;

M. Hiron,
None;

C. Guillou,
None;

C. Derambure,
None;

O. Boyer,
None;

X. Le Loët,
None;

O. Vittecoq,
None;

T. Lequerré,
None.

« Back to 2012 ACR/ARHP Annual Meeting

ACR Meeting Abstracts - https://acrabstracts.org/abstract/tnf%ce%b1-influences-rasgrp1-and-rasgrp3-expression-levels-in-pbmc-b-and-t-cells/