Semaphorin3A Rewires CD4

Semaphorin3A (Sema3A) is a regulatory protein found to be expressed on regulatory T and B cells and also secreted into peripheral blood. It has been identified as a potent immune regulator; however, not all its regulatory mechanisms have been evaluated. In this respect, we aim to investigate how Sema3A affects key metabolic pathways in T cells during homeostasis and rheumatoid arthritis (RA), and on the AKT/mTORC1 signaling axis. In this study, peripheral blood samples were collected from 119 healthy donors and 32 rheumatoid arthritis patients. T cells were subjected to Seahorse analysis to evaluate OXPHOS and glycolysis, live cell TMRE staining to evaluate mitochondrial activity, mass spectrometry for metabolite profiling, ATP determination to study ATP production, and Western blot analysis to investigate the signaling pathway activity. This study presents evidence showing that Sema3A inhibits the AKT/mTORC1 pathway, leading to a decreased glucose uptake and glycolysis disruption. Furthermore, we show that Sema3A reduces mitochondrial capacity and OXPHOS in activated T cells of healthy and RA donors, leading to a decreased ATP production. In contrast, Sema3A upregulates fatty acid oxidation (FA), probably as a backup pathway to ensure cell survival. Results with