Coenzyme A synthase controls pathogenic features of myelin-specific T cells by linking metabolic reprogramming to alteration of intracellular signaling pathways

In recent years, it has become clear that metabolism of immune cells critically influences the outcome of immune responses and contribute to the pathogenesis of autoimmunity. Thus, the emerging field of immunometabolism may hold the potential to discover new therapeutic targets for the treatment of autoimmune diseases. In the development of such pathologies, the involvement of Coenzyme A (CoA) metabolism was never directly investigated. The aim of this study was to investigate the involvement of CoA synthase (COASY), the enzyme that catalyzes the last two steps of CoA synthesis pathway, in the control of autoreactive T cell pathogenicity by using murine experimental autoimmune encephalomyelitis (EAE) as a model of autoimmune disease. By using metabolomics, proteomics and functional in vitro assays we investigated the pathogenic features of encephalitogenic PLP139-151(myelin)-specific effector T cells (PLP-T cells), which represent the major players in the pathogenesis of EAE in SJL mice. By performing metabolomics analysis, we have shown that PLP-T cells displayed reduced intracellular CoA synthesis, increased free fatty acids levels, and glycolysis-, Krebs cycle- and pentose phosphate pathway-related metabolites, compared to naïve T cells. In light of this, we investigated the immuno-modulatory effect of the CoA precursor pantethine (PTTH), on the pathogenic features of PLP-T cells and the impact of such immunomodulation on the development of EAE. CoA fueling, induced by PTTH treatment, reprogrammed autoreactive T cells, to a “naïve/resting-like state” leading them to reduce glycolysis, block pentose phosphate pathway, inhibit nucleic acid synthesis, and significantly alter lipid and protein content. Our phosphoproteomics analysis revealed that PTTH is able to affect crucial immune processes associated with the functionality and the pathogenicity of PLP-T cells, such as cell activation and proliferation, cytokine production and cell migration. These observations were confirmed by in vitro functional assays showing how CoA fueling strongly influenced PLP-T cells by reducing their antigen-specific proliferative capacity, pro-inflammatory cytokine production and their integrin-dependent adhesion. The role of PTTH, as an enhancer of the CoA synthesis pathway, was confirmed by the siRNA mediated silencing of COASY, which resulted in a significant loss of the inhibitory effect of PTTH on the proliferation rate of PLP-T cells. Interestingly, the knockdown of COASY in PLP-T cells increased their proliferation in absence of antigen stimulation, suggesting a key role of COASY in the control of autoreactive T cell activation. The potential role of COASY in the regulation of the immune response was corroborated by a bioinformatics analysis that showed a link between COASY and pathways like MAPK, RAC1 and mTOR. In light of the immuno-modulatory effect of CoA fueling on PLP-T cells in vitro, we sought to test the clinical potential of metabolic perturbation by PTTH in vivo. Pantethine treatment prevented the development of EAE by delaying the disease onset and acuteness. Furthermore, PTTH treatment started after disease onset significantly ameliorated the disease course. In conclusion, our data demonstrated a new role of CoA synthesis pathway in the metabolic reprogramming of autoreactive T cell necessary for their pathogenic features, suggesting the CoA fueling as a novel potential therapeutic target for the treatment of autoimmune diseases.