The Role of IL-15 in Activating STAT5 and Fine-Tuning IL-17A Production in CD4 T Lymphocytes This information is current as Pushpa Pandiyan, Xiang-Ping Yang, Senthil S. of September 25, 2021. Saravanamuthu, Lixin Zheng, Satoru Ishihara, John J. O'Shea and Michael J. Lenardo J Immunol 2012; 189:4237-4246; Prepublished online 19 September 2012; doi: 10.4049/jimmunol.1201476 Downloaded from http://www.jimmunol.org/content/189/9/4237 Supplementary http://www.jimmunol.org/content/suppl/2012/09/19/jimmunol.120147 Material 6.DC1 http://www.jimmunol.org/ References This article cites 56 articles, 14 of which you can access for free at: http://www.jimmunol.org/content/189/9/4237.full#ref-list-1 Why The JI? Submit online. • Rapid Reviews! 30 days* from submission to initial decision by guest on September 25, 2021 • No Triage! Every submission reviewed by practicing scientists • Fast Publication! 4 weeks from acceptance to publication *average Subscription Information about subscribing to The Journal of Immunology is online at: http://jimmunol.org/subscription Permissions Submit copyright permission requests at: http://www.aai.org/About/Publications/JI/copyright.html Email Alerts Receive free email-alerts when new articles cite this article. Sign up at: http://jimmunol.org/alerts The Journal of Immunology is published twice each month by The American Association of Immunologists, Inc., 1451 Rockville Pike, Suite 650, Rockville, MD 20852 All rights reserved. Print ISSN: 0022-1767 Online ISSN: 1550-6606. The Journal of Immunology The Role of IL-15 in Activating STAT5 and Fine-Tuning IL-17A Production in CD4 T Lymphocytes Pushpa Pandiyan,*,† Xiang-Ping Yang,‡ Senthil S. Saravanamuthu,x Lixin Zheng,* Satoru Ishihara,{ John J. O’Shea,‡ and Michael J. Lenardo* IL-15 is an important IL-2–related cytokine whose role in Th17 cell biology has not been fully elucidated. In this study, we show that exogenous IL-15 decreased IL-17A production in Th17 cultures. Neutralization of IL-15 using an Ab led to increases in IL- 17A production in Th17 cultures. Both Il152/2 and Il15r2/2 T cell cultures displayed higher frequency of IL-17A producers and higher amounts of IL-17A in the supernatants compared with those of wild-type (WT) cells in vitro. IL-15 down-modulated IL- 17A production independently of retinoic acid-related orphan receptor-gt, Foxp3, and IFN-g expression. Both Th17 cells and APCs produced IL-15, which induced binding of STAT5, an apparent repressor to the Il17 locus in CD4 T cells. Also, in a model of myelin oligodendrocyte glycoprotein-induced experimental autoimmune encephalomyelitis (EAE), Il152/2 mice displayed exac- Downloaded from erbated inflammation—correlating with increased IL-17A production by their CD4+ T cells—compared with WT controls. Exogenous IL-15 administration and IL-17A neutralization reduced the severity of EAE in Il152/2 mice. Taken together, these data indicate that IL-15 has a negative regulatory role in fine-tuning of IL-17A production and Th17-mediated inflammation. The Journal of Immunology, 2012, 189: 4237–4246. helper 17 cells are a subset of CD4+ T lymphocytes that cytokines such as IL-6, IL-21, and IL-23 promote Th17 dif- http://www.jimmunol.org/ are implicated in host defense against extracellular bac- ferentiation (7, 8). In contrast, STAT5, IL-2, and IL-27 negatively T teria and fungi (1–4). Although Th17 responses are im- regulate Th17 responses (9–12). However, the function of IL-15, a portant for host defense, they also contribute to immunopathology key cytokine for the development and proliferation of CD8 T cells in various disease settings. Th17 responses have been documented in and NK T cells, in regulation of Th17 responses has not been fully chronic inflammation and autoimmune diseases such as inflamma- elucidated. tory bowel disease (IBD), multiple sclerosis (MS), and rheumatoid IL-15 is one of the common g-chain (gc) cytokines similar and arthritis (RA) (5, 6). Because both protective and harmful effects structurally homologous to IL-2 and has pleiotropic roles in im- of Th17 cells during infection and chronic inflammation have been mune system development and lymphocyte homeostasis (13, 14). by guest on September 25, 2021 described, it is critical to study how Th17 responses are regulated The IL-15R consists of IL-15Ra (CD215), IL-2Rb (CD122), and in vivo. At the molecular level, transcription factors such as reti- the common g (CD132) chains. In addition to sharing the b and gc noic acid-related orphan receptor (ROR)-a and -gt and STAT3 and receptor subunits, IL-2 and IL-15 also share biological actions; namely, antiapoptotic effects on T cells, stimulation of NK cell *Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, proliferation, and cytolytic activity (15–18). However, striking † National Institutes of Health, Bethesda, MD 20892; Department of Biological Sci- differences are observed between the phenotypes of IL-2 and IL- ences, School of Dental Medicine, Case Western Reserve University, Cleveland, OH 2/2 44106; ‡Molecular Immunology and Inflammation Branch, National Institute of Ar- 15 knockout ( ) mice (17). This may be partly due to differ- thritis, Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, ences in the expression patterns of these two cytokines (19). MD 20892; xLaboratory of Molecular and Developmental Biology, National Eye Institute, National Institutes of Health, Bethesda, MD 20892; and {Laboratory of Whereas IL-2 is expressed primarily by activated CD4 T cells, IL- Cellular and Molecular Immunology, National Institute of Allergy and Infectious 15 is expressed mainly in nonlymphoid cells including the pa- Diseases, National Institutes of Health, Bethesda, MD 20892 renchymal cells of many organs, keratinocytes, skeletal muscle Received for publication May 31, 2012. Accepted for publication August 20, 2012. cells, and APCs such as monocytes and dendritic cells (20–24). In This work was supported by the intramural research program of the National Institute the nervous system, IL-15 is expressed by neurons, astrocytes, and of Allergy and Infectious Diseases, National Institutes of Health. P.P. was partially microglia (25, 26). Although initially it was believed that IL-15 is supported by a fellowship from the National Research Council, National Academy of Sciences. expressed in lymphocytes, recent studies have suggested that P.P. designed the study, performed experiments, and analyzed data with the supervi- activated lymphocytes indeed express IL-15 (21–24). The major sion of M.J.L. P.P. wrote and M.J.L. edited the manuscript. L.Z. measured the weight cells responding to IL-15 are lymphocytes, especially NK and of the mice, helped with manuscript preparation, recorded experimental autoimmune encephalomyelitis scores in masked fashion, and contributed to discussions. S.I. and memory T cells. Macrophage- and dendritic cell-derived IL-15Ra S.S.S. performed real-time PCR experiments and analyzed the data. J.J.O. and X.-P. binds to N-glycosylated IL-15 within the endoplasmic reticulum Y. helped P.P. in chromatin immunoprecipitation experiments. and brings IL-15 to the cell surface to deliver membrane-bound Address correspondence and reprint requests to Dr. Michael J. Lenardo and Dr. agonistic signals. This cell contact-dependent mechanism, called Pushpa Pandiyan, National Institutes of Health, 10 Center Drive, Building 10, Room 11N246, Bethesda, MD 20892. E-mail addresses: [email protected] (M.J.L.) and trans-presentation, is an important step in transmitting physio- [email protected] (P.P.) logical IL-15Ra–IL-15 signals to most cells (27). After receptor The online version of this article contains supplemental material. engagement, IL-15 signaling activates both STAT3 and STAT5 Abbreviations used in this article: gc, g-chain; ChIP, chromatin immunoprecipitation; transcription factors to exert its regulatory functions in immune EAE, experimental autoimmune encephalomyelitis; IBD, inflammatory bowel dis- cells (28). ease; MOG, myelin oligodendrocyte glycoprotein; MS, multiple sclerosis; qPCR, quantitative PCR; qRT-PCR, quantitative real-time PCR; RA, rheumatoid arthritis; IL-15 has been implicated in a variety of inflammatory con- ROR, retinoic acid-related orphan receptor; WT, wild-type. ditions. Increased circulating IL-15 levels have been found in www.jimmunol.org/cgi/doi/10.4049/jimmunol.1201476 4238 IL-15 RESTRICTS Th17 RESPONSES Crohn’s and ulcerative colitis patients, implying that IL-15 pro- anti-CD3 and 3 mg/ml anti-CD28 Abs under Th0 or Th17 conditions for 3– motes the disease (29, 30). However, one study has shown that IL- 8 d. Th0 cells were stimulated only with anti-CD3 and anti-CD28 Abs with 15 protects against colitis in mice (31). Whether IL-15 controls no added cytokines, and Th17 cells were polarized using IL-6 (20 ng/ml), TGF-b (2 ng/ml), anti–IFN-g (6 mg/ml) and anti–IL-4 (6 mg/ml). Where IBD directly by regulating Th17 cells is unknown. In patients with indicated, APCs were added at a T cell/APC ratio of 1:1, and T cells were RA, IL-15 is considered proinflammatory, and blocking of IL-15 CFSE labeled to assess their proliferation. When indicated, cytokines, using anti–IL-15 mAb (HuMax-IL-15) ameliorated symptoms anti–IL-15 (20 mg/ml), and anti–IL-2 (10 mg/ml) were added at the be- (32). In the mouse collagen-induced arthritis model, although ginning of stimulation of cocultures. 2/2 wild-type (WT) and Il15 mice showed equal susceptibility to Quantitative PCR analyses the disease, transgenic overexpression of IL-15 increased the disease severity by enhancing the proliferation of CD4 T cells and For quantitative PCR (qPCR) analyses of ROR-a, ROR-gt, Foxp3, and IL- their production of IFN-g and IL-17A (33). Again, whether or not 17A mRNA, naive CD4 T cells were stimulated in Th17 cultures as de- scribed earlier, and RNA was recovered using an RNeasy Micro Kit IL-15 exerts a direct effect on IL-17A expression in CD4 cells and (Qiagen).