A Novel Role of Histone Deacetylase 11 (HDAC11) in the Regulation of IL-10 Production and Immune Tolerance Mediated by Antigen-Presenting Cells.

Abstract Antigen-presenting cells (APC) can induce T-cell activation as well as T-cell tolerance. The induction of such a divergent outcomes is determined by the inflammatory status of the APC at the time of encounter with antigen specific T-cells. The molecular basis by which the APC regulate this critical decision of the immune system remain not well understood. Chromatin modification induced by acetylation/deacetylation of histones plays an important role in regulation of gene transcription, including genes involved in the inflammatory response. Histone deacetylases, a set of enzymes involved in histone modification are molecular targets for histone deacetylase inhibitors (HDI), novel compounds being evaluated as anticancer drugs. Interestingly, in addition to their antitumor properties, HDI have been also shown to modulate inflammatory responses. We evaluated therefore whether treatment with the hydroxamic acid analogue pan-HDAC inhibitor LAQ824 could influence the inflammatory status of the APC and their ability to determine CD4+ T-cell priming versus tolerance. In vitro treatment of APCs with LAQ824 resulted in enhanced acetylation of histones H-2A, H-2B, H3 and H4, increased expression of the co-stimulatory molecule B7.2 and enhanced production of pro-inflammatory mediators such as IL-1a, IL-1-b, IL-6, IL-12, TNF-a and RANTES in response to LPS stimulation. To our surprise, a dose-dependent inhibition of IL-10 mRNA and protein was observed in APCs treated with LPS and LAQ824. Chromatin immune precipitation (CHIP) assays indicate that this particular effect of LAQ824 involves histone modifications at the IL-10-promoter level. Given this inhibitory effect of LAQ824 and the central role of IL-10 in immune tolerance, we asked next whether a specific histone deacetylase(s) could predominantly influence IL-10 gene expression. By utilizing a reporter gene carrying the IL10 promoter fused to a luciferase gene, plasmids coding for Flag-tagged versions of all HDACs and plasmids carrying siRNA for specific silencing of HDACs, we found that among all the HDACs evaluated, HDAC11 negatively regulates the production of IL-10 in APCs. Importantly, treatment of APCs with LAQ824 resulted in increased expression of HDAC 11, diminished IL-10 production and the generation of APCs that effectively prime naive CD4+ T-cells and restore the responsiveness of tolerized antigen-specific T-cells from lymphoma bearing hosts. Taken together, we have demonstrated for the first time that HDAC11, a member of the HDAC family with no prior defined physiological role, is involved in regulation of IL-10 gene expression. Furthermore, our findings that HDAC11 expression in APCs can be manipulated by treatment of these cells with LAQ824, points to HDAC11 as a novel therapeutic target to influence immune activation versus immune tolerance, a critical decision with significant implications in autoimmunity, transplantation and cancer immunotherapy.

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A Novel Role for Histone Deacetylase 6 (HDAC6) in the Regulation of IL-10 and Immune Tolerance Mediated by Antigen-Presenting Cells (APCs).

Blood ◽

10.1182/blood.v114.22.1360.1360 ◽

2009 ◽

Vol 114 (22) ◽

pp. 1360-1360

Author(s):

Fengdong Cheng ◽

Hongwei Wang ◽

Noreen Luetteke ◽

Javier Pinilla ◽

Alan Kozikowski ◽

...

Keyword(s):

Gene Expression ◽

T Cells ◽

T Cell ◽

Gene Transcription ◽

Immune Tolerance ◽

Cd4 T Cells ◽

Research Funding ◽

Inflammatory Status ◽

C Terminus ◽

Antigen Presenting

Abstract Abstract 1360 Poster Board I-382 There is now an undisputed recognition that bone marrow (BM) derived APCs can induce T-cell activation as well as T-cell tolerance to tumor antigens. The inflammatory status of the APC at the time of tumor antigen presentation, rather than its phenotype, has been proposed as explanation for the induction of such divergent T-cell outcomes. The molecular basis by which the APC regulate this critical decision remain however to be fully elucidated. Recently, we have focused our efforts to mechanistically understand the regulation of inflammatory/anti-inflammatory genes in their natural setting, the chromatin substrate, and how changes at this level could influence the overall inflammatory status of the APC. In particular, we have studied the consequences of chromatin modification by deacetylation of histone tails (mediated by histone deacetylases) upon expression of IL-10, an immunosuppressive cytokine that plays a central role in tolerance induction. By utilizing a reporter gene carrying the IL10 promoter fused to a luciferase gene, and plasmids encoding Flag-tagged versions of specific HDACs, we found that among all the HDACs evaluated, overexpression of HDAC6 in the APC resulted in transcriptional activation of IL-10 gene expression. Conversely, knockdown of HDAC6 in APCs using shRNA specific for murine HDAC6 resulted in abrogation of IL-10 gene transcription in response to LPS, as compared to APCs transduced with nontarget control (NT). Similar results were found when APCs were treated with the hydroxamate-based selective HDAC6 inhibitors, compound 3 (ST-3-06) and compound 7 (ST-292). Treatment of APCs with either compound resulted in a dose-dependent inhibition of IL-10 production in response to LPS. This effect was specific for IL-10, since no inhibition of other cytokines was observed in HDAC6 inhibitor-treated cells. Next, we evaluated the antigen-presenting capabilities of APCs in which HDAC6 was either knocked down or pharmacologically inhibited. In vitro culture of these APCs with naïve CD4+ T cells specific for a MHC class II restricted epitope of influenza hemagglutinin (HA) in the presence of cognate HA peptide resulted in enhanced activation of antigen-specific T cells since they produce higher levels of IL-2 and IFN-g ƒnrelative to clonotypic T cells encountering antigen on control APCs. Importantly, APCs lacking HDAC6 were capable of restoring the responsiveness of tolerized CD4+ T cells isolated from tumor-bearing mice. Our results suggest a role for HDAC6 in positively regulating IL-10 gene transcription in APCs, an effect that it is opposite to the recently described role of HDAC11 as a negative regulator IL-10 gene transcription1. To address whether a potential crosstalk between these two HDACs could represent a novel mechanism to tightly regulate IL-10 gene expression, we first performed confocal studies that revealed that HDAC6 and HDAC11 indeed colocalize in the cytoplasm. Coimmunoprecipitation confirmed that HDAC6 and HDAC11 interact. Furthermore, by using Flag-tagged HDAC6 wild type (1-1215) or Flag-tagged HDAC6 mutants lacking the C-terminus domain we demonstrated that the C-terminus portion of HDAC6 is required for its interaction with HDAC11. Taken together, we have demonstrated for the first time that HDAC6 regulates IL-10 gene expression, an effect that influences the overall inflammatory status of APC and determines antigen-specific T-cell responses. Importantly, inhibition of HDAC6 in APC with specific HDAC inhibitors represents a novel therapeutic approach to tip the balance towards immune activation rather than immune tolerance, a critical decision with significant implications for cancer immunotherapy. 1Villagra et al. Nature Immunology, 10:92-100, 2009 Disclosures Pinilla: Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Bristol-Myers Squibb: Research Funding; exelixis: Research Funding.

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Abstract 252: Interleukin-27 Signaling Regulates Myeloid Cells Activation in Atherosclerosis

Arteriosclerosis Thrombosis and Vascular Biology ◽

10.1161/atvb.36.suppl_1.252 ◽

2016 ◽

Vol 36 (suppl_1) ◽

Author(s):

Iuliia Peshkova ◽

Aliia Fatkhullina ◽

Ekaterina Koltsova

Keyword(s):

T Cells ◽

T Cell ◽

Inflammatory Cytokines ◽

Antigen Presenting Cells ◽

Atherosclerotic Lesions ◽

Mediators Of Inflammation ◽

Antigen Presenting ◽

Deficient Mice ◽

Pro Inflammatory Cytokines

Atherosclerosis is a lipid-driven inflammatory disease characterized by the progressive plaque growth in the vessels. Cytokines are important mediators of inflammation and atherosclerosis. While pro-inflammatory cytokines were extensively investigated, little is known about the role of anti-inflammatory cytokines as to their ability to control vascular inflammation. We tested whether immunoregulatory IL-27R signaling is important to control inflammation in mouse models of atherosclerosis. We found that atherosclerosis-prone mice with hematopoietic deficiency of IL-27R ( Ldlr -/- mice reconstituted with bone marrow from Il27ra -/- ) or global deficiency ( Il27ra -/- x Apoe -/- ) developed significantly larger atherosclerotic lesions compared to controls. Atherosclerotic lesions in IL-27R deficient mice contained more CD45 + leukocytes and CD4 + T cells, which produced pro-atherogenic cytokines IL-17A and TNF-α. These cytokines normally suppressed by IL-27, regulated the expression of CCL2 and other chemokines, which in turn led to accumulation of myeloid CD11b + and CD11c + cells in atherosclerotic aortas. Using two-photon microscopy, we found enhanced interactions between antigen presenting cells and T cells in the aortas of IL-27R deficient mice accompanied by enhanced CD4 T cell proliferation. Moreover, macrophages in Il27ra -/- aortas also demonstrated enhanced ability to produce pro-inflammatory cytokines, including IL-1. The blockade of IL-1R signaling, however, strongly suppressed atherosclerosis progression in IL-27R deficient but not control mice, suggesting an important role of IL-27 in the regulation of IL-1 production in atherosclerosis. Overall, our data demonstrate that IL-27R signaling in atherosclerosis is required to control function of antigen presenting cells modulating subsequent T cell activation in the aortas. Moreover, it controls macrophage activation and pro-inflammatory myeloid cell-derived cytokine production. These mechanisms altogether curb pathogenic T cell lineage differentiation and, thus, atherosclerosis, suggesting potent anti-atherogenic role of IL-27.

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A Crucial Role for Antigen Presenting Cells in Donor CD4+CD25+ Regulatory T Cell Mediated Suppression of Experimental Gvhd.

Blood ◽

10.1182/blood.v114.22.688.688 ◽

2009 ◽

Vol 114 (22) ◽

pp. 688-688

Author(s):

Isao Tawara ◽

Tomomi Toubai ◽

Chelsea Malter ◽

Yaping Sun ◽

Evelyn Nieves ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Cd8 T Cells ◽

Conflicts Of Interest ◽

Antigen Presenting Cells ◽

Class Ii ◽

Indoleamine 2 ◽

Effector Phase ◽

Antigen Presenting

Abstract Abstract 688 Several lines of evidence show that donor derived mature CD4+CD25+Foxp3+ regulatory T cells (Tregs) suppress experimental GVHD. The mechanism of GVHD suppression by donor Tregs is, however, not well understood. Recent observations have brought in a renewed focus on the role of professional antigen presenting cells (APCs) in the induction and maintenance of GVHD by alloreactive T cell effectors (Teffs). But the role of APCs in modulating the responses of Tregs after allogeneic BMT is not known. We first tested the requirement of host APCs in Treg mediated regulation of GVHD. We utilized a clinically relevant CD8+ T cell dependent MHC matched but miHA disparate C3H.SW (H-2b) → wild type (wt) or Class II deficient Abb (II-/-) B6 (H-2b) model of GVHD because host APCs and target tissues from the Abb animals do not express class II and as such donor CD4+CD25+ Tregs will not directly interact with the host tissues while alloreactive CD8+ T cells could still respond to miHA allo-antigens presented by the intact class I on host APCs. The recipient Abb (II-/-) and wt B6 animals were lethally irradiated and transplanted with 2 × 105 CD8+ T cells along with or without CD4+CD25+ Tregs at 1:2 ratio from either syngeneic B6 or allogeneic C3H.SW animals. The wt recipients that received Tregs showed significantly better survival compared with the wt animals that did not receive any Tregs (P< 0.01) while the class II-/- animals showed similar GVHD mortality regardless of Treg infusion (P>0.8). To confirm whether the lack of Treg mediated protection was only due to the absence of interaction with host type APCs and also to exclude the possibility of development of Tregs from the infused BM we thymectomized wt B6 animals and then generated [B6 B6] controls and the [Abb B6] chimeras. These chimeric animals were used as recipients in a second BMT and transplanted with CD8+ Teffs and Tregs from allogeneic C3H.SW mice. Tregs reduced GVHD mortality in the [B6 B6] (P<0.01) but not in the [Abb B6] animals (P>0.7). We next evaluated whether host APC expression of allo-antigens alone was sufficient for Treg mediated GVHD protection in the absence of class II expression on target tissues by generating [B6 B6] and [B6 Abb] chimeras and found that Tregs demonstrated equivalent GVHD protection even when the class II allo-antigens were expressed only on the host APCs. Mechanistic studies demonstrated that Tregs significantly inhibited the expansion of CD8+ Teffs on days +10 and 17 after BMT in the spleens of the WT recipients (P<0.05) but not in the class II-/- animals. However, infused Tregs demonstrated reduced expansion in the class II-/- animals only early after BMT (on day +10) but was equivalent at later time-point (days 17 and 29) to the WT recipients. We further determined the mechanisms by which host APCs might contribute to Treg mediated protection. To this end we used IL-10-/-, indoleamine 2, 3 dioxygenase (IDO)-/- deficient animals and generated [IL-10-/- B6] and [IDO-/- B6] animals as recipients. Tregs mitigated GVHD mortality regardless of the ability of the host APCs to express IL-10 or IDO. We next determined whether Tregs suppressed Teffs in their activation phase at the level of their interaction with host APCs or in the effector phase. C3H.SW CD8+ T cells were primed (both in vivo and ex vivo with B6 allo-antigens) and then infused into the [β2mg-/- B6] animals such that pre-activated CD8 Teffs would still be able to initiate GVHD without the need for host APCs for their activation. Infusion of donor Tregs into [β2mg-/- B6] animals that were transplanted with the pre-activated Teffs mitigated GVHD severity demonstrating that Tregs, once activated by host APCs, were capable of suppressing Teff cells in their effector phase. Collectively our data show (a) host APCs are critical (b) expression of allo-antigens on host target tissues is not obligatory (c) host derived IL-10 and IDO are not critical for Treg mediated GVHD protection and (d) Tregs can mitigate GVHD by suppressing alloreactive Teffs in the effector phase even after they have been activated. Disclosures: No relevant conflicts of interest to declare.

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Decay-accelerating factor regulates T-cell immunity in the context of inflammation by influencing costimulatory molecule expression on antigen-presenting cells

Blood ◽

10.1182/blood-2011-04-348474 ◽

2011 ◽

Vol 118 (4) ◽

pp. 1008-1014 ◽

Cited By ~ 13

Author(s):

Chongyun Fang ◽

Takashi Miwa ◽

Wen-Chao Song

Keyword(s):

T Cells ◽

T Cell ◽

Knockout Mice ◽

Antigen Presenting Cells ◽

T Cell Immunity ◽

Decay Accelerating Factor ◽

Cell Immunity ◽

Complement Regulator ◽

Antigen Presenting

Abstract Recent studies have indicated a role of complement in regulating T-cell immunity but the mechanism of action of complement in this process remains to be clarified. Here we studied mice deficient in decay-accelerating factor (DAF), a key membrane complement regulator whose deficiency led to increased complement-dependent T-cell immune responses in vivo. By crossing OT-II and OT-I T-cell receptor transgenic mice with DAF-knockout mice, we found that lack of DAF on T cells did not affect their responses to antigen stimulation. Similarly, lack of DAF on antigen-presenting cells (APCs) of naive mice did not alter their T-cell stimulating activity. In contrast, APCs from DAF-knockout mice treated with inflammatory stimuli were found to be more potent T-cell stimulators than cells from similarly treated wild-type mice. Acquisition of higher T-cell stimulating activity by APCs in challenged DAF-knockout mice required C3 and C5aR and was correlated with decreased surface PD-L1 and/or increased CD40 expression. These findings implied that DAF suppressed T-cell immunity as a complement regulator in the context of inflammation but did not play an intrinsic role on T cells or APCs. Collectively, our data suggest a systemic and indirect role of complement in T-cell immunity.

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Activation of Reactive Versus Malignant T Cells in Cutaneous T Cell Lymphoma: Role of Abnormal Antigen Presenting Cells and T Cell Activating Molecules

Basic Mechanisms of Physiologic and Aberrant Lymphoproliferation in the Skin ◽

10.1007/978-1-4615-1861-7_3 ◽

1994 ◽

pp. 29-38 ◽

Cited By ~ 1

Author(s):

Kevin D. Cooper ◽

May-Sen Lee ◽

Darius Mehregen ◽

Erik Hansen ◽

Ole Baadsgaard ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Cell Lymphoma ◽

Antigen Presenting Cells ◽

T Cell Lymphoma ◽

Cutaneous T Cell Lymphoma ◽

Antigen Presenting ◽

Malignant T Cells

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Teaching T cells to remember : the role of antigen presenting cells in the development of CD4+ T cell memory

10.32469/10355/9741 ◽

2009 ◽

Author(s):

Jason Scott Ellis

Keyword(s):

T Cells ◽

T Cell ◽

Antigen Presenting Cells ◽

Cd4 T Cell ◽

T Cell Memory ◽

Cell Memory ◽

Antigen Presenting

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Notch Is a Novel Critical Signaling Pathway Regulating Responses of T Cell and Antigen Presenting Cells in Multiple Murine aGVHD Models

Blood ◽

10.1182/blood.v126.23.5418.5418 ◽

2015 ◽

Vol 126 (23) ◽

pp. 5418-5418

Author(s):

Xiaodan Luo ◽

Pengfei Qin ◽

Chunyan Wang ◽

Zhenqian Huang ◽

Huo Tan

Keyword(s):

T Cells ◽

Body Weight ◽

T Cell ◽

Signaling Pathway ◽

Antigen Presenting Cells ◽

Hematopoietic Stem ◽

Secretase Inhibitor ◽

Donor T Cells ◽

Antigen Presenting

Abstract Introduction: Acute graft-versus-host disease (aGVHD) is a potentially life-threatening complication mediated by both host-derived antigen presenting cells (APCs) and donor T cells after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Despite prophylaxis and treatments, aGVHD stell occurs in many allo-HSCT patients. The role of Notch1 signal inhibition becomes more and more important in aGVHD study. This study is to investigate the role of Notch1 inhibition by γ-secretase inhibitor DAPT in murine aGVHD model. Methods: We established a C57BL/6 BALB/c murine aGVHD model. γ-secretase inhibitor-DAPT is used to inhibit Notch1 signal in vivo and in vitro before transplantation. The degree of clinical and histopathologic GVHD is assessed by aGVHD scores and body weight. The functions of host-derived APCs and donor T cells are analyzed by flow cytometry, ELISA and PCR. Results: All mice survived at least 14 days after transplantation and all of them developed aGVHD (n=20). The expression of Hes-1, as one of the target genes of Notch1 signal pathway, decreased significantly after DAPT inhibition. Body weight of mice in control groups decreased significantly compared to mice with Notch1 inhibition by DAPT after transplantation. Notch1 inhibited recipients produced markedly decreased amounts of the pro-inflammatory cytokines IFN-γ. The expressions of CD4 and Foxp3 increased while CD11c, CD80 and CD86 decreased after Notch1 inhibition. Conclusions: These results indicate that Notch is a novel critical signaling pathway regulating responses of T cell and antigen presenting cells in multiple murine aGVHD models. Notch signaling inhibition appears to limit the harmful effects of aGVHD. Disclosures No relevant conflicts of interest to declare.

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