PPARβ/δ-orchestrated metabolic reprogramming supports the formation and maintenance of memory CD8+ T cells

The formation of antigen-specific memory CD8+ T cells is one of the most important features of the adaptative immune system, allowing the establishment of long-term protection against secondary infections. Although emerging evidence suggests that metabolic reprogramming is crucial for memory T cell differentiation and survival, the underlying mechanisms that drive metabolic rewiring needed for memory T cells remain unclear. Here, we found that the nuclear receptor peroxisome proliferator-activated receptor-beta/delta (PPARβ/δ) was upregulated to instruct the metabolic reprogramming, including downregulation of aerobic glycolysis and the promotion of oxidative metabolism and fatty acid oxidation, that occurs during the transition toward the establishment of central memory CD8+ T cells. Mechanistically, the exposure to interleukin-15 (IL-15) and expression of T cell factor 1 (TCF1) could coordinately activated the PPARβ/δ pathway during acute viral infection and chronic antigen exposure contexts, counteracting apoptosis induced by antigen clearance and metabolic stress. Together, our work indicates that PPARβ/δ is a master metabolic regulator orchestrating the metabolic reprogramming required for the establishment of a metabolic profile favorable for T cells longevity. 10K P14 WT and PPARb deficient CD8+ T cells were transferred in B6 host which were infected the next next with LCMV Armstrong. After 28 days, the spleens were collected and the central memory CD8+ transferred cells WT and KO were sorted (CD62l+ CD127+). RNA was extracted using the RNeasy® Mini Kit (Qiagen) following the instructions of the manufacturer. Bulk RNA-seq was then performed.