Bcl6 controls granzyme B expression in effector CD8<sup>+</sup> T cells

In adoptive therapy, CD8 T cells expressing active STAT5 (STAT5CA) transcription factors were found to be superior to unmanipulated counterparts in long-term persistence, capacity to infiltrate autochthonous mouse melanomas, thrive in their microenvironment, and induce their regression. However, the molecular mechanisms sustaining these properties were undefined. In this study, we report that STAT5CA induced sustained expression of genes controlling tissue homing, cytolytic granule composition, type 1 CD8 cytotoxic T cell–associated effector molecules granzyme B+, IFN-γ+, TNF-α+, and CCL3+, but not IL-2, and transcription factors T-bet and eomesodermin (Eomes). Chromatin immunoprecipitation sequencing analyses identified the genes possessing regulatory regions to which STAT5 bound in long-term in vivo maintained STAT5CA-expressing CD8 T cells. This analysis identified 34% of the genes differentially expressed between STAT5CA-expressing and nonexpressing effector T cells as direct STAT5CA target genes, including those encoding T-bet, Eomes, and granzyme B. Additionally, genes encoding the IL-6R and TGFbRII subunits were stably repressed, resulting in dampened IL-17–producing CD8 T cell polarization in response to IL-6 and TGF-β1. The absence of T-bet did not affect STAT5CA-driven accumulation of the T cells in tissue or their granzyme B expression but restored IL-2 secretion and IL-6R and TGFbRII expression and signaling, as illustrated by IL-17 induction. Therefore, concerted STAT5/T-bet/Eomes regulation controls homing, long-term maintenance, recall responses, and resistance to polarization towards IL-17–producing CD8 T cells while maintaining expression of an efficient type 1 CD8 cytotoxic T cell program (granzyme B+, IFN-γ+).

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“…1A). This result is in agreement with the reported repression of Bcl6 expression by STAT5 (11) and repression by Bcl6 of GzmB expression (39).…”

Section: Stat5ca Expression In In Vivo-transferred Cd8 T Cells Inducesupporting

confidence: 93%

“…4); indirect regulation through increased T-bet/Eomes expression, as well as decreased Bcl6 expression, as the latter TF is a known repressor of GzmB transcription (39); and/or complementation between the T-box members T-bet and Eomes (Fig. 5).…”

Section: Discussionmentioning

confidence: 99%

Active STAT5 Regulates T-bet and Eomesodermin Expression in CD8 T Cells and Imprints a T-bet–Dependent Tc1 Program with Repressed IL-6/TGF-β1 Signaling

Grange

Verdeil

Arnoux

et al. 2013

The Journal of Immunology

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“…Bcl-6 is a key regulator in Th-cell differentiation and in the regulation of CD4 + and CD8 + T-cell memory (40). Although it has been demonstrated before that Bcl-6 is transiently expressed in activated T cells and continuously up-regulated in CD8 + effector T cells (41), its role in these cells is less understood. Here, we could demonstrate that Bcl-6 prevents CTLA-4 from being expressed in these cells.…”

Section: Discussionmentioning

confidence: 99%

Mannose receptor induces T-cell tolerance via inhibition of CD45 and up-regulation of CTLA-4

Schuette

Embgenbroich

Ulas

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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The mannose receptor (MR) is an endocytic receptor involved in serum homeostasis and antigen presentation. Here, we identify the MR as a direct regulator of CD8 + T-cell activity. We demonstrate that MR expression on dendritic cells (DCs) impaired T-cell cytotoxicity in vitro and in vivo. This regulatory effect of the MR was mediated by a direct interaction with CD45 on the T cell, inhibiting its phosphatase activity, which resulted in up-regulation of cytotoxic T-lymphocyte-associated Protein 4 (CTLA-4) and the induction of T-cell tolerance. Inhibition of CD45 prevented expression of B-cell lymphoma 6 (Bcl-6), a transcriptional inhibitor that directly bound the CTLA-4 promoter and regulated its activity. These data demonstrate that endocytic receptors expressed on DCs contribute to the regulation of T-cell functionality.T he mannose receptor (MR) is an endocytic receptor belonging to the C-type lectin family and is expressed by distinct populations of dendritic cells (DCs), macrophages, and endothelial cells (1). It consists of an N-terminal cysteine-rich domain (CR), a fibronectin type II (FN II) domain, eight C-type lectinlike domains (CTLDs), a transmembrane region, and a short intracellular region. The CTLDs of the MR can bind to glycoconjugates terminated in mannose, fucose, or glucose. Despite the presence of eight CTLDs, only CTLD4 is responsible for carbohydrate binding. Additionally, the MR can bind to sulfated carbohydrates via its CR and to collagen via its FN II domain (1).In a previous study, we demonstrated that antigens internalized by the MR are processed specifically for cross-presentation (2). The correlation between the MR and cross-presentation offered the possibility that antigens targeted toward the MR could induce potent cytotoxic T-cell responses. Because the induction of a strong cytotoxic T-cell response against tumor-specific antigens is a crucial process in many tumor vaccination strategies, antigen targeting toward the MR seemed to be a promising approach. However, in in vivo tumor models, antigen targeting toward the MR did not result in a strong cytotoxic T-cell response but, instead, led to the induction of antigen-specific T-cell tolerance (3, 4). Therefore, we analyzed whether the MR has a regulatory effect on the induction of immune responses by means distinct from antigen uptake and presentation, and we investigated a direct influence of the MR on T-cell activation. We could demonstrate that the presence of the MR on the antigen-presenting cell (APC) directly impairs the cytotoxic activity of T cells in vitro and in vivo. We showed that this effect was due to a direct interaction of the MR with CD45 on the T-cell surface. This interaction inhibited CD45 activity and resulted in the up-regulation of the inhibitory molecule cytotoxic T-lymphocyte-associated Protein 4 (CTLA-4), which was responsible for the impaired cytotoxic activity of the T cells. ResultsThe Presence of the MR on DCs Reduces Cytotoxic Activity of CD8 + T Cells. To investigate whether the MR influences T-cell ...

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“…Total RNA was reverse transcribed with Superscript III Reverse Transcriptase (Invitrogen Life Technologies) and oligo(dT) (Amersham Biosciences, Piscataway, NJ), and the cDNAs were used for PCR. Real-time RT-PCR was performed as described elsewhere (38). Real-time PCR with cDNAs was conducted using SYBR Green PCR Master Mix (Applied Biosystems, Foster City, CA) and run on an ABI Prism 7000 Sequence Detection System (Applied Biosystems).…”

Section: Real-time Quantitative Rt-pcrmentioning

confidence: 99%

Bcl6 Is Required for the Development of Mouse CD4+ and CD8α+ Dendritic Cells

Ohtsuka

Sakamoto

Pan

et al. 2011

The Journal of Immunology

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Th2-type inflammation spontaneously shown in Bcl6-knockout (KO) mice is mainly caused by bone marrow (BM)-derived nonlymphoid cells. However, the function of dendritic cells (DCs) in Bcl6-KO mice has not been reported. We show in this article that the numbers of CD4+ conventional DCs (cDCs) and CD8α+ cDCs, but not of plasmacytoid DCs, were markedly reduced in the spleen of Bcl6-KO mice. Generation of cDCs from DC progenitors in BM cells was perturbed in the spleen of irradiated wild-type (WT) mice transferred with Bcl6-KO BM cells, indicating an intrinsic effect of Bcl6 in cDC precursors. Although cDC precursors were developed in a Bcl6-KO BM culture with Fms-like tyrosine kinase 3 ligand, the cDC precursors were more apoptotic than WT ones. Also p53, one of the molecular targets of Bcl6, was overexpressed in the precursors. The addition of a p53 inhibitor to Bcl6-KO BM culture protected apoptosis, suggesting that Bcl6 is required by cDC precursors for survival by controlling p53 expression. Furthermore, large numbers of T1/ST2+ Th2 cells were naturally developed in the spleen of Bcl6-KO mice. Th2 skewing was accelerated in the culture of WT CD4 T cells stimulated with Ags and LPS-activated Bcl6-KO BM-derived DCs, which produced more IL-6 and less IL-12 than did WT DCs; the addition of anti–IL-6 Abs to the culture partially abrogated the Th2 skewing. These results suggest that Bcl6 is required in cDC precursors for survival and in activated DCs for modulating the cytokine profile.

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Bcl6 controls granzyme B expression in effector CD8⁺ T cells

Cited by 56 publications

References 37 publications

Active STAT5 Regulates T-bet and Eomesodermin Expression in CD8 T Cells and Imprints a T-bet–Dependent Tc1 Program with Repressed IL-6/TGF-β1 Signaling

Active STAT5 Regulates T-bet and Eomesodermin Expression in CD8 T Cells and Imprints a T-bet–Dependent Tc1 Program with Repressed IL-6/TGF-β1 Signaling

Mannose receptor induces T-cell tolerance via inhibition of CD45 and up-regulation of CTLA-4

Bcl6 Is Required for the Development of Mouse CD4+ and CD8α+ Dendritic Cells

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Bcl6 controls granzyme B expression in effector CD8+ T cells

Cited by 56 publications

References 37 publications

Active STAT5 Regulates T-bet and Eomesodermin Expression in CD8 T Cells and Imprints a T-bet–Dependent Tc1 Program with Repressed IL-6/TGF-β1 Signaling

Active STAT5 Regulates T-bet and Eomesodermin Expression in CD8 T Cells and Imprints a T-bet–Dependent Tc1 Program with Repressed IL-6/TGF-β1 Signaling

Mannose receptor induces T-cell tolerance via inhibition of CD45 and up-regulation of CTLA-4

Bcl6 Is Required for the Development of Mouse CD4+ and CD8α+ Dendritic Cells

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Bcl6 controls granzyme B expression in effector CD8⁺ T cells