Effect of PP2A deficiency on gene expression in CD8+ T cells activation [bulkRNA-Seq]

Protein phosphatase 2A (PP2A) is one of the most abundant serine/threonine phosphatases and plays critical roles in regulating cell fate and function. We previously showed that PP2A regulates the differentiation of CD4+ T cells and the development of thymocytes. Nevertheless, its role in CD8+ T cells remains elusive. By ablating the catalytic subunit a (Ca) of PP2A in CD8+ T cells, we revealed the essential role of PP2A in promoting the effector functions of CD8+ T cells. Notably, PP2A Ca-deficient CD8+ T cells exhibit reduced proliferation and decreased cytokine production upon stimulation in vitro. In vivo, mice lacking PP2A Ca in T cells displayed defective immune responses against lymphocytic choriomeningitis virus infection, associated with reduced CD8+ T cell expansion and decreased cytokine production. Consistently, the ablation of the PP2A Ca subunit in CD8+ T cells results in attenuated antitumor activity in mice. There is a notable decrease in the infiltration of PP2A Ca-deficient CD8+ T cells within the tumor microenvironment, and the cells that do infiltrate exhibit diminished effector functions. Mechanistically, PP2A Ca deficiency impedes CD28-induced AKT Ser473 phosphorylation, thus impairing CD8+ T cell costimulation signal. Collectively, our findings underscore the critical role of phosphatase PP2A as a propeller for CD28-mediated costimulation signaling in CD8+ T cell effector function by fine-tuning T cell activation. Overall design: To inveatigate the role of PP2A in CD8+ T cell effector function, we isolated naïve CD8+ T cells from 8-week-old WT and PP2A cKO mice. Then we performed gene expression profiling analysis using data obtained from RNA-seq of WT and PP2A cKO CD8+ T cells stimulated by anti-CD3+CD28 for 1h.