mTORC1-GLUT1-mediated glucose metabolism drives hyperactivation of B cells in primary Sjogren's syndrome

Primary Sjögren's syndrome (pSS) is a chronic systemic autoimmune disease characterized by B cell hyperactivation and hypergrammaglobulinemia. Currently, the role of metabolic pathways in the B cells of pSS patients is poorly defined. Here, we showed that upon cytosine phosphate-guanine (CpG)/sCD40L/IL-4 stimulation, B cells proportionally increased glycolysis and oxygen consumption, and compared with B cells from healthy controls (HCs), B cells from pSS patients exhibited higher glycolysis capacity and maximal oxidative respiration (OXPHOS). We also found that glucose transporter 1 (GLUT1) expression in B cells from pSS patients was significantly higher than that in B cells from HCs. Treatment with 2-deoxy-d-glucose (2-DG) inhibited the activation of B cells in pSS patients. Both 2-DG and Metformin inhibited the proliferation, formation of plasma/plasmablasts and decreased the IgG and IgM levels in the supernatants of B cells from pSS patients. Furthermore, inhibition of mTORC1 by rapamycin had an effect similar to that of 2-DG, suppressing B cell activation, proliferation and antibody production. Taken together, we demonstrated that B cells from pSS patients are more metabolically active than those from HCs and suggested that the mTORC1-GLUT1 glycolysis pathways were the major drivers of B cell hyperactivation and autoantibody production in pSS patients.