Epigenetic and transcriptional signatures of stable versus plastic differentiation of proinflammatory γδ T cell subsets

Abstract

Two distinct subsets of γδ T cells that produce interleukin 17 (IL-17) (CD27 − γδ T cells) or interferon-γ (IFN-γ) (CD27 + γδ T cells) develop in the mouse thymus, but the molecular determinants of their functional potential in the periphery remain unknown. Here we conducted a genome-wide characterization of the methylation patterns of histone H3, along with analysis of mRNA encoding transcription factors, to identify the regulatory frames of peripheral IFN-γ-producing or IL-17-producing γδ T cell subsets in vivo. We found that CD27 + γδ T cells were committed to the expression of Ifng but not Il17, whereas CD27 − γδ T cells displayed permissive chromatin configurations at loci related to both the T H 17 and T H 1 subsets of helper T cells and differentiated into cells producing both IL-17 and IFN-γ in a tumor microenvironment.γδ T cells have emerged as key providers of interleukin 17 (IL-17) in various models of infection, inflammation and autoimmunity [1][2][3][4][5][6] . Antibody-mediated or genetic depletion of γδ T cells greatly reduces disease severity in IL-17-driven models of chronic inflammation [1][2][3][4]7 . Those results notwithstanding, many reports have made a compelling case for γδ T cells as the main producers of interferon-γ (IFN-γ) in both mice and humans 8 , which has been a major foundation for clinical trials targeting these lymphocytes in cancer immunotherapy 9 . Given the dual ability of γδ cells to produce IL-17 and IFN-γ, published work has aimed to contributed to designing the study and writing the manuscript; A.Q.G. helped to design and supervise the study; and B.S.-S. designed and supervised the study and wrote the manuscript. COMPETING FINANCIAL INTERESTSThe authors declare no competing financial interests.Reprints and permissions information is available online at http://www.nature.com/reprints/index.html. Europe PMC Funders GroupAuthor Manuscript Nat Immunol. Author manuscript; available in PMC 2016 April 18. Europe PMC Funders Author ManuscriptsEurope PMC Funders Author Manuscripts identify markers that associate with functional attributes of mouse γδ T cells [10][11][12][13] . Expression of the costimulatory receptor CD27 segregates IL-17-producing (CD27 − ) γδ T cells and IFN-γ-producing (CD27 + ) γδ T cells in both naive and Plasmodium-infected C57BL/6 mice 10 . Moreover, the chemokine receptor CCR6, which is expressed exclusively on CD27 − γδ T cells, constitutes an additional marker for IL-17 + γδ T cells 13,14. Both CD27 + and CD27 − γδ T cell subsets show spontaneous cytokine secretion after activation, in contrast to the delayed differentiation of conventional CD4 + T cells of the T H 1 or T H 17 subset of helper T cells 15 . That finding is highlighted by the observation that 30-40% of peripheral γδ T cells freshly isolated from naive mice produce either IL-17 or IFN-γ after 3 h of restimulation in vitro 10 . Those functionally mature γδ T cell subsets are also found in the thymus, as early as the embryonic stages of mouse development [10][11][12]16 . Moreove...

A Genome-Wide Analysis Identifies a Notch–RBP-Jκ–IL-7Rα Axis That Controls IL-17–Producing γδ T Cell Homeostasis in Mice

“…1C). Supporting this result, recent genome-wide epigenetic analysis of CCR6 + IL-17 + gd T cells showed enrichment of active H3K4me2 marks, but no repressive H3K27me3 marks, in the putative RBP-Jk binding site (25.4 kb), suggesting a permissive epigenetic status (31). These results suggest that, in murine gd T cells, ICN1 is specifically bound at the novel promoter site, 25.4 kb upstream of the TSS of IL-7Ra, possibly through the putative RBP-Jk binding site.…”

“…In an oral infection mouse model with Listeria monocytogenes, IFN-g + IL-17 + gd T cells were detected postinfection (54). A recent genomewide epigenetic analysis revealed that IL-17 + gd T cells had the ability to become IFN-g producers (31). These results suggested the possibility that IFN-g + IL-17 + gd T cells were derived from IL-17 + gd T cells via an unknown mechanism induced by IL-7.…”

Murine CD27 (−) Vγ6 (+) γδ T cells producing IL-17A promote ovarian cancer growth via mobilization of protumor small peritoneal macrophages

“…Interestingly, CD27 (−) γδ T cells in the secondary lymphoid organs have been shown to express higher levels of IL-7R, IL-1R1, and IL-23R than their IFN-γ-secreting counterparts (30,42,43), a property that seems to be transcriptionally acquired and epigenetically sustained (42). Among the type-17-driving cytokines, IL-7 was the most consistently up-regulated throughout ID8 growth, and its exogenous administration showed a tendency to increase the tumor load.…”

“…Therefore, both IL-17 and IFN-γ are likely to be involved in multiple cellular events taking place within the inflammatory tumor microenvironment as well as in draining lymph nodes. Along these lines, it should also be noted that IL-17 + γδ T cells can (under strong inflammatory conditions) differentiate into IL-17/IFN-γ double producers, whose function in the tumor milieu remains to be established (42,57). Gene expression analysis for tgfb, vegfa, cxcl1, mif, il1b, gata6, il17ra, and cd163 was performed by RT-qPCR and normalized to the housekeeping gene hprt.…”

Dermal-Resident versus Recruited γδ T Cell Response to Cutaneous Vaccinia Virus Infection

“…Emerging data from studies of cells in central lymphoid organs suggest that CD27 delineates gd T cell functional subsets, leading to a paradigm shift for how gd T cells are classified (11,29).…”