/NFAT Signaling 2+ Alternative Splicing and Ca Processing Proteins and Modulates Activated T Cell PRMT5 Promotes Symmetric Dimethylation of RNA

Protein arginine methyltransferase (PRMT) 5 is the type 2 methyltransferase catalyzing symmetric dimethylation of arginine. PRMT5 inhibition or deletion in CD4 Th cells reduces TCR engagement-induced IL-2 production and Th cell expansion and confers protection against experimental autoimmune encephalomyelitis, the animal model of multiple sclerosis. However, the mechanisms by which PRMT5modulates Th cell proliferation are still not completely understood, and neither are the methylation targets in T cells. In this manuscript, we uncover the role of PRMT5 on alternative splicing in activatedmouse T cells and identify several targets of PRMT5 symmetric dimethylation involved in splicing. In addition, we find a possible link between PRMT5-mediated alternative splicing of transient receptor potential cation channel subfamily Mmember 4 (Trpm4) and TCR/NFAT signaling/IL-2 production. This understandingmay guide development of drugs targeting these processes to benefit patients with T cell–mediated diseases. ImmunoHorizons, 2021, 5: 884–897. Received for publication August 11, 2021. Accepted for publication October 1, 2021. Address correspondence and reprint requests to:Mireia Guerau-de-Arellano, The Ohio State University, 453 W. 10th Avenue, Room 535C, Columbus, OH 43210. E-mail address: mireia.guerau@osumc.edu ORCIDs: 0000-0003-1680-1315 (S. Sengupta); 0000-0002-9632-7205 (K.O.W.); 0000-0001-9254-7078 (S. Sanghvi); 0000-0001-9205-8258 (G.L.); 0000-00030271-6574 (L.M.A.); 0000-0002-5300-0448 (P.N.T.); 0000-0002-6135-1897 (H.S.); 0000-0003-2442-4679 (K.L.P.); 0000-0002-0600-4593 (M.G.-d.-A.) This work was supported by National Institutes of Health (NIH)/National Institute of Allergy and Infectious Diseases Grants R01AI121405 and 1R21AI127354 (both to M.G.d.A.), start-up funds from The Ohio State University School of Health and Rehabilitation Sciences (to M.G.d.A.), an American Association of Immunologists Travel for Techniques Award (to M.G.d.A. and S. Sengupta), the Comprehensive Cancer Center Mass Spectrometry Resource (Core Cancer Center Support Grant S10OD018056), NIH/National Cancer Institute Grant 01-CA186729 (to P.N.T.), a Pelotonia postdoctoral fellowship (to G.L.), and the National Center for Advancing Translational Sciences, which sponsors the Center for Clinical and Translational Science Award (Grant UL1TR002733). The content is the sole responsibility of the authors and does not necessarily represent the official views of the National Center for Advancing Translational Sciences or the NIH. The RNA sequencing data in resting T cells associated with the RNA sequencing experiment have been submitted to the Gene Expression Omnibus (https://www.ncbi.nlm.nih. gov/geo/) under accession number GSE181931. Abbreviations used in this article:C, expected percent spliced value; DC, expected change inC; AJ, alternative junction; AS, alternative splicing; EAE, experimental autoimmune encephalomyelitis; GO, Gene Ontology; IP, immunoprecipitation; KO, knockout; LC-MS/MS, liquid chromatography/tandem MS; LSV, local splice variant; MAJIQ, modeling alternative junction inclusion quantification; MS, mass spectrometry; MS/MS, tandem mass spectrometry; PRMT, protein arginine methyltransferase; RNA-Seq, RNA sequencing; SDM, symmetric dimethylation, symmetrically dimethylated; sh, short hairpin; SL, stem loop; snRNA, small nuclear RNA; Trpm4, transient receptor potential cation channel subfamily M member 4. The online version of this article contains supplemental material. This article is distributed under the terms of the CC BY-NC-ND 4.0 Unported license. Copyright © 2021 The Authors 884 https://doi.org/10.4049/immunohorizons.2100076 ImmunoHorizons is published by The American Association of Immunologists, Inc. RESEARCH ARTICLE