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Prostaglandin E 2 signaling networks in T cells revealed through a systems approach
Author(s) -
Lone Anna Mari,
Giansanti Piero,
Jørgensen Marthe Jøntvedt,
Gjerga Enio,
Dugourd Aurelien,
Scholten Arjen,
SaezRodriguez Julio,
Heck Albert,
Tasken Kjetil
Publication year - 2019
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.2019.33.1_supplement.lb258
Subject(s) - phosphoproteomics , signal transduction , microbiology and biotechnology , kinase , cd8 , biology , prostaglandin e2 receptor , phosphorylation , receptor , cell signaling , immune system , t cell , chemistry , cancer research , protein kinase a , biochemistry , immunology , protein phosphorylation , agonist
Prostaglandin E 2 (PGE 2 ) plays a crucial role in immune homeostasis, inflammation and cancer. Elevated in several cancers, PGE 2 promotes tumor progression and an immunosuppressive tumor microenvironment, partly through its actions on T cells. Currently, we lack a comprehensive view of the signaling pathways and networks that PGE 2 triggers through its four distinct receptors (EP1‐EP4) in different T cells subsets. Here, we use a two‐pronged approach based on phosphoproteomics and phosphoflow cytometry in combination with highly specific agonists and antagonists of EP1–4 to fully characterize PGE 2 signaling in T cell subsets, including CD4, CD8 and Tregs. Phosphoproteomics revealed >1000 phosphosites regulated upon EP1–4 triggering, among them novel sites as well as sites with known biological function. Phosphosites identified were specifically regulated by one receptor, or by several, indicating potential receptor cross‐talk. Functional analyses demonstrated the involvement of PGE 2 signaling in key immunological processes. Phosphorylation motif characterization and kinase predictions confirmed the involvement of kinases such as PKC, CDKs, CK2, MAPKs and PKA, and revealed signaling differences between CD4 and CD8 cells. Modeling of the MS data enabled visualization of predicted networks. Phosphoflow cytometry studies elucidated signaling kinetics, including differences in signal duration between EP2 and EP4 receptors, which both signal through Gα s . Cell type differences observed by phosphoflow mirrored the phosphoproteomics data, with the highest signaling levels observed in EP2‐stimulated CD8 cells and different T cell subtypes exhibiting distinct signaling pathways. Predicted kinases, notably PKA and CK2, were verified using kinase inhibitors, and further kinases involved in PGE 2 signaling, including PI3K and Src, were also identified. Finally, we used logic‐based models to understand the organization and dynamic behavior of the networks. In sum, we present a comprehensive and detailed view of PGE 2 signaling nodes, pathways and networks in T cells, thus improving the current understanding of PGE 2 's role in T cells and providing a solid foundation for targeted and hypothesis‐based investigations of PGE 2 signaling and functions in T cells. Support or Funding Information Norwegian Cancer Society, Health South‐East, Research Council of Norway, EU‐project Prime‐XS. This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .