Dimethyl Fumarate Modulates T Cell Metabolism and Function in Systemic Lupus Erythematosus Patient Samples

Background Activated T cells make a significant contribution to inflammation in systemic lupus erythematosus (SLE). Their ability to secrete proinflammatory cytokines and express activating NK receptors allows them to mediate inflammation. We know that cellular metabolism regulates the activation of T cells. A phase II study has reported on efficacy of DMF in cutaneous lupus [1]. Evidence from patients with multiple sclerosis indicates that dimethyl fumarate (DMF), an electrophile, targets cellular metabolism to modulate T cell activation and function [2]. However, the potential of DMF to modulate T cell metabolism and activation in SLE is not known. Objectives We investigated whether DMF modulates T cell metabolism, activation and function in samples from patients with SLE in a series of in vitro experiments. Methods All experiments were performed using isolated T cells from freshly drawn whole blood samples from patients with SLE. T cells were isolated using negative selection using Stem cell or Miltenyei magnetic bead separation kit. Isolated T cells were activated with anti-CD3 and IL-2 and incubated with either DMF at 25μM concentration or DMSO alone for three or seven days at 37°C and 5% CO2 before harvesting and analysing on BD FACS flow cytometer. Analysis of cytokines in supernatants was performed using cytometric bead arrays. Flow jo software was used to analyse flow cytometry files. Graph Pad Prism software was used to perform statistical analysis. Results In Seahorse experiments, after three days of incubation dimethyl fumarate (DMF) inhibited the oxygen consumption rate (OCR) and extra cellular acidification rate (ECAR) in isolated T cells when compared with samples incubated with vehicle, dimethyl sulfoxide (DMSO). Our results revealed that DMF significantly inhibited: 1) aerobic glycolysis and oxidative phosphorylation in activated CD4+T cells from patients with SLE (n=4), in vitro; 2) T cell activation and proliferation as assessed by a reduction in the frequency of CD69 (n=4) and Ki67 (n=2) positivity, respectively. Collectively, these results suggest that DMF inhibits T cell activation and proliferation in samples from patients with SLE. After 7 days of incubation, DMF significantly inhibited the expression of activating NK receptors CD158a and NKG2D on CD4+T cells whereas DMF seemed to have a trend toward enhancing the expression of inhibitory NK receptors NKG2A and CD158b (n=6). After 7 days of incubation, DMF significantly reduced CD4+T cell intracellular expression of IFN-γ, TNF-α, IL-17 and secretion of pro-inflammatory cytokines IFN-γ and TNF-α in supernatants (n=6). Conclusion Our data indicated that DMF modulates metabolic programming, both glycolysis and oxidative phosphorylation, to inhibit activation, proliferation, and secretion of proinflammatory cytokines from CD4+T cells from patients with SLE. These results provide strong mechanistic rationale for considering dimethyl fumarate as a novel therapeutic agent to treat systemic lupus erythematosus. References [1]Kuhn A, Landmann A, Patsinakidis N, Ruland V, Nozinic S, Perusquia Ortiz AM, et al. Fumaric acid ester treatment in cutaneous lupus erythematosus (CLE): a prospective, open-label, phase II pilot study. Lupus. 2016;25(12):1357-64. [2]Kornberg MD, Bhargava P, Kim PM, Putluri V, Snowman AM, Putluri N, et al. Dimethyl fumarate targets GAPDH and aerobic glycolysis to modulate immunity. Science. 2018;360(6387):449-53. Acknowledgements The study received full funding support from the biomedical research centre, University College Hospital. Dr. Reddy’s work was supported by MRC-CARP fellowship award. Disclosure of Interests Loren Kell: None declared, Samuel Taylor: None declared, Kavina Shah: None declared, Roel De Maeyer: None declared, David Isenberg Consultant of: no competing interest with submitted work, Grant/research support from: no competing interest with submitted work, Madhura Castelino: None declared, Geraldine Cambridge: None declared, Debajit Sen: None declared, Maria José Leandro Consultant of: no competing interest with submitted work, Grant/research support from: Roche Glycart, Arne Akbar: None declared, Venkat Reddy Grant/research support from: Roche Glycart, no competing interest with submitted work.