OP0196 IMBALANCE BETWEEN MEMORY TH1 AND TH1-TREG CELLS DEPENDS ON DIFFERENTIAL REGULATION OF CELL METABOLISM IN PATIENTS WITH SLE

Abstract

Background T helper 1 (Th1) cells play an important role in Systemic Lupus Erythematosus (SLE). However, which abnormalities generated in Th1 cells may be related to the pathogenesis of SLE remains elusive. “Immunometabolism” has recently attracted much attention. We previously reported that both IFN-γ and T-bet positively regulated aerobic glycolysis, leading to activation of Th1 cells in mice (REF1). This suggests a potentially important role for metabolic reprograming in human Th1 cells and the pathogenesis of SLE which requires further investigation. Objectives In this study, we assessed the abnormality of metabolism in Th1 cells in patients with SLE. In addition, we investigated which abnormalities of Th1 cells are generated via metabolic reprograming in vitro. Methods Peripheral blood mononuclear cells (PBMCs) were obtained from 31 age-matched healthy donors (HDs) and 60 patients with SLE. Th1- and metabolism-related markers in CD4+ T cells were measured by flow cytometry. In addition, the correlation of these markers with clinical characteristics was investigated. Next, CD4+CD45RA- cells were purified from peripheral of HDs, and the effect of mTORC1 inhibitor Rapamycin (Rapa) or glycolysis inhibitor 2DG on characteristic changes in Th1 cells were assessed in vitro. Results Baseline characteristics of patients with SLE were males: females=5:55, age 41.1 years, disease duration 142.3 months, SLEDAI 11.5 and BILAG 12.9 at the timing of admission due to exacerbation of SLE. Activated effector memory CD4+T-bethi cells in patients with SLE were higher than HCs. The CD4+T-bethi cells had high potential for IFN-γ production. mTORC1 acts as a regulator of cell growth through the phosphorylation of substrates that potentiate anabolic processes such as aerobic glycolysis. The CD4+T-bethi cells highly expressed p-mTORC1, and this was closely related to treatment-resistance, but not disease activity and autoantibodies such as anti ds-DNA Abs (Treatment resistance was defined as refractory to >3 kinds of immunosupressants and/or 2> re-increase to high dose corticosteroid). Therefore, we examined the effect of Rapa or 2DG to such memory mTORC1+T-bet+IFNγ+CD4+ cells in vitro. When CD45RA-CD4+ cells were isolated from peripheral blood of HDs and stimulated with anti-CD3/CD28 Abs, T-bet expression and IFN-γ production as well as p-mTOC1 expression and glycolysis were induced. Interestingly, 2DG, but not Rapa, suppressed IFN-γ production and, in contrast, enhanced IL-2 production. Therefore, we hypothesized that 2DG induced Th1-Treg cells, reported as one of Treg cell subsets (REF2). 2DG induced FoxP3hiT-bet+IFN-γ- (Th1-Treg like) cells and suppressed FoxP3-T-bet+IFN-γ+ (Th1 like) cells. Meanwhile, Rapa induced FoxP3intT-bet+IFN-γ+ (non-Treg like) cells and did not affect to FoxP3-T-bet+IFN-γ+ (Th1 like) cells. Finally, we examined the involvement of Th1-Treg cells to the pathogenesis of SLE. CD45RA-FoxP3intIFN-γ+ (non-Treg) cells as well as T-bethi (Th1 like) cells were increased, whereas CD45RA-FoxP3hiCXCR3+T-bethi (Th1-Treg) cells were decreased in SLE. Conclusion These results indicate that activated effector memory Th1 cells were increased while memory Th1-Treg cells were decreased in patients with SLE. Importantly, metabolic modulators redressing the imbalance of helper T subsets have potential as a new therapeutic strategy.