scholarly journals The Tyrosine Kinase Tec Regulates Effector Th17 Differentiation, Pathogenicity, and Plasticity in T-Cell-Driven Intestinal Inflammation

2021 ◽  
Vol 12 ◽  
Author(s):  
Lisa Sandner ◽  
Marlis Alteneder ◽  
Ci Zhu ◽  
Anastasiya Hladik ◽  
Sandra Högler ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Tyrosine Kinase ◽  
Adoptive Transfer ◽  
Th17 Cells ◽  
Negative Regulator ◽  
Fine Tuning ◽  
T Helper ◽  
Stat3 Phosphorylation ◽  
Th17 Differentiation

T helper (Th) 17 cells are not only key in controlling infections mediated by extracellular bacteria and fungi but are also triggering autoimmune responses. Th17 cells comprise heterogeneous subsets, some with pathogenic functions. They can cease to secrete their hallmark cytokine IL-17A and even convert to other T helper lineages, a process known as transdifferentiation relying on plasticity. Both pathogenicity and plasticity are tightly linked to IL-23 signaling. Here, we show that the protein tyrosine kinase Tec is highly induced in Th17 cells. Th17 differentiation was enhanced at low interleukin-6 (IL-6) concentrations in absence of Tec, which correlates with increased STAT3 phosphorylation and higher Il23r expression. Therefore, we uncovered a function for Tec in the IL-6 sensing via STAT3 by CD4+ T cells, defining Tec as a fine-tuning negative regulator of Th17 differentiation. Subsequently, by using the IL-17A fate mapping mouse combined with in vivo adoptive transfer models, we demonstrated that Tec not only restrained effector Th17 differentiation but also pathogenicity and plasticity in a T-cell intrinsic manner. Our data further suggest that Tec regulates inflammatory Th17-driven immune responses directly impacting disease severity in a T-cell-driven colitis model. Notably, consistent with the in vitro findings, elevated levels of the IL-23 receptor (IL-23R) were observed on intestinal pre- and postconversion Th17 cells isolated from diseased Tec−/− mice subjected to adoptive transfer colitis, highlighting a fundamental role of Tec in restraining IL-23R expression, likely via the IL-6-STAT3 signaling axis. Taken together, these findings identify Tec as a negative regulator of Th17 differentiation, pathogenicity, and plasticity, contributing to the mechanisms which help T cells to orchestrate optimal immune protection and to restrain immunopathology.

scholarly journals A Novel Role for IL-6 Receptor Classic Signaling: Induction of RORγt+Foxp3+ Tregs with Enhanced Suppressive Capacity

2019 ◽  
Vol 30 (8) ◽  
pp. 1439-1453 ◽  
Author(s):  
Julia Hagenstein ◽  
Simon Melderis ◽  
Anna Nosko ◽  
Matthias T. Warkotsch ◽  
Johannes V. Richter ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Adoptive Transfer ◽  
Th17 Cells ◽  
Inflammatory Diseases ◽  
Double Positive ◽  
T Effector Cells ◽  
Suppressive Capacity

BackgroundNew therapies blocking the IL-6 receptor (IL-6R) have recently become available and are successfully being used to treat inflammatory diseases like arthritis. Whether IL-6 blockers may help patients with kidney inflammation currently remains unknown.MethodsTo learn more about the complex role of CD4+ T cell-intrinsic IL-6R signaling, we induced nephrotoxic nephritis, a mouse model for crescentic GN, in mice lacking T cell–specific IL-6Ra. We used adoptive transfer experiments and studies in reporter mice to analyze immune responses and Treg subpopulations.ResultsLack of IL-6Ra signaling in mouse CD4+ T cells impaired the generation of proinflammatory Th17 cells, but surprisingly did not ameliorate the course of GN. In contrast, renal damage was significantly reduced by restricting IL-6Ra deficiency to T effector cells and excluding Tregs. Detailed studies of Tregs revealed unaltered IL-10 production despite IL-6Ra deficiency. However, in vivo and in vitro, IL-6Ra classic signaling induced RORγt+Foxp3+ double-positive Tregs (biTregs), which carry the trafficking receptor CCR6 and have potent immunoregulatory properties. Indeed, lack of IL-6Ra significantly reduced Treg in vitro suppressive capacity. Finally, adoptive transfer of T cells containing IL-6Ra−/− Tregs resulted in severe aggravation of GN in mice.ConclusionsOur data refine the old paradigm, that IL-6 enhances Th17 responses and suppresses Tregs. We here provide evidence that T cell–intrinsic IL-6Ra classic signaling indeed induces the generation of Th17 cells but at the same time highly immunosuppressive RORγt+ biTregs. These results advocate caution and indicate that IL-6–directed therapies for GN need to be cell-type specific.

scholarly journals Generation of BCR-ABL Reactive CD4+ T Helper Cells By Reprograming and Redifferentiation

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 3424-3424
Author(s):  
Norihiro Ueda ◽  
Yasusi Uemura ◽  
Rhong Zhang ◽  
Shuichi Kitayama ◽  
Yutaka Yasui ◽  
...  
Keyword(s):  
T Cells ◽  
Stem Cell ◽  
T Cell ◽  
Tyrosine Kinase ◽  
Research Funding ◽  
T Helper ◽  
Th Cells ◽  
Hematopoietic Stem ◽  
Chugai Pharmaceutical ◽  
Dc Maturation

Abstract Chronic myeloid leukemia (CML) is a clonal hematopoietic stem cell disorder caused by BCR-ABL fusion protein that has constitutively active tyrosine kinase activity. Although the prognosis of the patient with CML in chronic phase has markedly improved by the advent of tyrosine kinase inhibiters, the management of the patients with CML in advanced phase remains to be the major challenge. Immunotherapy is considered to be one of the promising treatment strategies for refractory CML. BCR-ABL fusion region, b3a2 peptide, represents a neo-epitope that can induce CML-specific immune responses. The activation of b3a2 peptide-specific CD4+ T helper (Th) cells and their interaction with dendritic cells (DCs) can induce a robust cytotoxic T lymphocyte (CTL)-mediated anti-leukemic immunity through epitope spreading. However, current vaccination strategies cannot effectively induce the proliferation of antigen-specific Th cells in vivo, presumably due to the tumor-induced immunosuppressive milieu. In addition, ex vivo expansion of antigen-specific Th cells attenuates their effector functions by expansion-related cell senescence, and the procedure to establish antigen-specific Th cells for each patient's treatment is too complicated for the clinical application. The purpose of the present study is to establish a method to generate large amounts of functional b3a2-specific CD4+ Th cells enough for the treatment of the patients with refractory CML by using induced pluripotent stem cell (iPSC) technology. First, we established b3a2-specific CD4+ Th clone from peripheral blood mononuclear cells of a healthy donor positive for HLA-DRB1*09:01 and HLA-A*24:02. The Th clone recognized b3a2 peptide in the context of HLA-DR9 and exhibited a Th1 profile. Second, we established iPSCs from the Th clone and differentiated them into T cell lineage by coculture with OP9 stromal cells expressing Notch ligand Delta-like 1. The iPSC-derived T cells (b3a2-iPS-T cells) expressed the same T cell antigen receptor (TCR) as the original Th clone but not CD4 molecule. Because CD4 acts as a co-receptor in the TCR-mediated Th responses, we transduced b3a2-iPS-T cells with CD4 gene. The CD4-expressing b3a2-iPS-T cells (CD4+ b3a2-iPS-T cells) recognized b3a2 peptide in the context of HLA-DR9 as the original Th clone. Moreover, CD4+ b3a2-iPS-T cells activated by b3a2 peptide induced DC maturation, as indicated by the upregulation of CD86 on DCs. In the additional presence of HLA-A24-restricted Wilms tumor 1 (WT1) peptide, the mature DCs stimulated primary expansion of WT1-specific CTLs. The CTLs exerted cytotoxicity against WT1 peptide-loaded HLA-A24 positive cell lines. These data suggest that the CD4+ b3a2-iPS-T cells have a potential to induce effective anti-leukemic immunity via DC maturation and subsequent CTL responses. The current approach enable to provide large amounts of b3a2 specific CD4+ Th-like cells that would augment CTL-mediated anti-leukemic responses via DC maturation, which may contribute to the treatment of patients with refractory CML. Disclosures Kiyoi: Yakult Honsha Co.,Ltd.: Research Funding; FUJIFILM Corporation: Patents & Royalties, Research Funding; Eisai Co., Ltd.: Research Funding; Kyowa Hakko Kirin Co., Ltd.: Consultancy, Research Funding; Sumitomo Dainippon Pharma Co., Ltd.: Research Funding; Zenyaku Kogyo Co., Ltd.: Research Funding; Novartis Pharma K.K.: Research Funding; Mochida Pharmaceutical Co., Ltd.: Research Funding; Astellas Pharma Inc.: Consultancy, Research Funding; Nippon Shinyaku Co., Ltd.: Research Funding; FUJIFILM RI Pharma Co.,Ltd.: Research Funding; Nippon Boehringer Ingelheim Co., Ltd.: Research Funding; Alexion Pharmaceuticals: Research Funding; MSD K.K.: Research Funding; Japan Blood Products Organization: Research Funding; Takeda Pharmaceutical Co., Ltd.: Research Funding; Pfizer Inc.: Research Funding; Bristol-Myers Squibb: Research Funding; Chugai Pharmaceutical Co., Ltd.: Research Funding; Taisho Toyama Pharmaceutical Co., Ltd.: Research Funding; Teijin Ltd.: Research Funding. Naoe:Celgene K.K.: Research Funding; Otsuka Pharmaceutical Co., Ltd.: Research Funding; Toyama Chemical CO., LTD.: Research Funding; Kyowa Hakko Kirin Co., Ltd.: Patents & Royalties, Research Funding; Chugai Pharmaceutical Co., Ltd.: Patents & Royalties; FUJIFILM Corporation: Patents & Royalties, Research Funding; Nippon Boehringer Ingelheim Co., Ltd.: Research Funding; Pfizer Inc.: Research Funding; Astellas Pharma Inc.: Research Funding. Kaneko:AsTlym Co., Ltd: Other: founder, shareholder and scientific adviser.

scholarly journals Phosphoprotein Associated with Glycosphingolipid-Enriched Microdomains (Pag), a Novel Ubiquitously Expressed Transmembrane Adaptor Protein, Binds the Protein Tyrosine Kinase Csk and Is Involved in Regulation of T Cell Activation

2000 ◽  
Vol 191 (9) ◽  
pp. 1591-1604 ◽  
Author(s):  
Tomás̆ Brdic̆ka ◽  
Dagmar Pavlis̆tová ◽  
Albrecht Leo ◽  
Eddy Bruyns ◽  
Vladimír Kor̆ínek ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Tyrosine Kinase ◽  
T Cell Activation ◽  
Peripheral Blood ◽  
Adaptor Protein ◽  
Jurkat Cells ◽  
Negative Regulator ◽  
Membrane Microdomains ◽  
Quiescent State

According to a recently proposed hypothesis, initiation of signal transduction via immunoreceptors depends on interactions of the engaged immunoreceptor with glycosphingolipid-enriched membrane microdomains (GEMs). In this study, we describe a novel GEM-associated transmembrane adaptor protein, termed phosphoprotein associated with GEMs (PAG). PAG comprises a short extracellular domain of 16 amino acids and a 397-amino acid cytoplasmic tail containing ten tyrosine residues that are likely phosphorylated by Src family kinases. In lymphoid cell lines and in resting peripheral blood α/β T cells, PAG is expressed as a constitutively tyrosine-phosphorylated protein and binds the major negative regulator of Src kinases, the tyrosine kinase Csk. After activation of peripheral blood α/β T cells, PAG becomes rapidly dephosphorylated and dissociates from Csk. Expression of PAG in COS cells results in recruitment of endogenous Csk, altered Src kinase activity, and impaired phosphorylation of Src-specific substrates. Moreover, overexpression of PAG in Jurkat cells downregulates T cell receptor–mediated activation of the transcription factor nuclear factor of activated T cells. These findings collectively suggest that in the absence of external stimuli, the PAG–Csk complex transmits negative regulatory signals and thus may help to keep resting T cells in a quiescent state.

Plasticity of human Th17 cells and iTregs is orchestrated by different subsets of myeloid cells

Blood ◽  
2011 ◽  
Vol 117 (24) ◽  
pp. 6532-6541 ◽  
Author(s):  
Bastian Hoechst ◽  
Jaba Gamrekelashvili ◽  
Michael P. Manns ◽  
Tim F. Greten ◽  
Firouzeh Korangy
Keyword(s):  
T Cells ◽  
T Cell ◽  
Regulatory T Cells ◽  
Cd4 T Cells ◽  
Th17 Cells ◽  
Human Peripheral Blood ◽  
Myeloid Cells ◽  
T Cell Subsets ◽  
T Helper ◽  
Hla Dr

Abstract CD4+ T helper cell differentiation is essential for mounting robust immune responses without compromising unresponsiveness toward self-tissue. Here, we show that different subsets of myeloid cells isolated from human peripheral blood modulate TGF-β–dependent CD4+ T-cell developmental programs ex vivo. Human CD14+HLA-DR−/low myeloid-derived suppressor cells (MDSCs) induce Foxp3+ regulatory T cells, whereas CD14+HLA-DR+ monocytes promote generation of IL-17–secreting RORc+ Th17 cells when cocultured with naive CD4+ T cells. More importantly, not only do these 2 subsets modulate the de novo induction of Tregs and Th17 cells from CD4+ T cells, but MDSCs also catalyze the transdifferentiation of Foxp3+ regulatory T cells from monocyte-induced Th17 cells. The mechanism of such Th17 plasticity is dependent on MDSC-derived TGF-β and retinoic acid. Our results identify a previously unknown feature of the different subsets of CD14+ myeloid cells namely their pivotal role in immune response regulation and plasticity of CD4+ T helper cells. We propose that different subsets of myeloid cells in humans can orchestrate the differentiation of naive CD4+ T cells into effector/regulatory T-cell subsets. The balance between these 2 subsets can impact the outcome of immune reaction from inflammation to tolerance.

scholarly journals Social Defeat Modulates T Helper Cell Percentages in Stress Susceptible and Resilient Mice

2019 ◽  
Vol 20 (14) ◽  
pp. 3512 ◽  
Author(s):  
Oliver Ambrée ◽  
Christina Ruland ◽  
Peter Zwanzger ◽  
Luisa Klotz ◽  
Bernhard T Baune ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Function ◽  
Social Defeat ◽  
Cell Phenotype ◽  
T Helper ◽  
Altered Expression ◽  
Expression Levels ◽  
Th17 Differentiation ◽  
And Function

Altered adaptive immunity involving T lymphocytes has been found in depressed patients and in stress-induced depression-like behavior in animal models. Peripheral T cells play important roles in homeostasis and function of the central nervous system and thus modulate behavior. However, the T cell phenotype and function associated with susceptibility and resilience to depression remain largely unknown. Here, we characterized splenic T cells in susceptible and resilient mice after 10 days of social defeat stress (SDS). We found equally decreased T cell frequencies and comparably altered expression levels of genes associated with T helper (Th) cell function in resilient and susceptible mice. Interleukin (IL)-17 producing CD4+ and CD8+ T cell numbers in the spleen were significantly increased in susceptible mice. These animals further exhibited significantly reduced numbers of regulatory T cells (Treg) and decreased gene expression levels of TGF-β. Mice with enhanced Th17 differentiation induced by conditional deletion of PPARγ in CD4+ cells (CD4-PPARγKO), an inhibitor of Th17 development, were equally susceptible to SDS when compared to CD4-PPARγWT controls. These data indicate that enhanced Th17 differentiation alone does not alter stress vulnerability. Thus, SDS promotes Th17 cell and suppresses Treg cell differentiation predominantly in susceptible mice with yet unknown effects in immune responses after stress exposure.

scholarly journals Protein C receptor (PROCR) is a negative regulator of Th17 pathogenicity

2016 ◽  
Vol 213 (11) ◽  
pp. 2489-2501 ◽  
Author(s):  
Yasuhiro Kishi ◽  
Takaaki Kondo ◽  
Sheng Xiao ◽  
Nir Yosef ◽  
Jellert Gaublomme ◽  
...  
Keyword(s):  
T Cells ◽  
Th17 Cells ◽  
Protein C ◽  
Activated Protein C ◽  
Negative Regulator ◽  
Cell Surface Molecule ◽  
Cooperative Action ◽  
Th17 Differentiation

Th17 cells are key players in defense against pathogens and maintaining tissue homeostasis, but also act as critical drivers of autoimmune diseases. Based on single-cell RNA-seq profiling of pathogenic versus nonpathogenic Th17 cells, we identified protein C receptor (PROCR) as a cell surface molecule expressed in covariance with the regulatory module of Th17 cells. Although PROCR expression in T cells was controlled by the cooperative action of the Th17 lineage-specific transcription factors RORγt, IRF4, and STAT3, PROCR negatively regulated Th17 differentiation. CD4+ T cells from PROCR low expressor mutant mice readily differentiated into Th17 cells, whereas addition of the PROCR ligand, activated protein C, inhibited Th17 differentiation in vitro. In addition, PROCR acted as a negative regulator of Th17 pathogenicity in that it down-regulated expression of several pathogenic signature genes, including IL-1 and IL-23 receptors. Furthermore, T cell–specific deficiency of PROCR resulted in the exacerbation of experimental autoimmune encephalomyelitis (EAE) and higher frequencies of Th17 cell in vivo, indicating that PROCR also inhibits pathogenicity of Th17 cells in vivo. PROCR thus does not globally inhibit Th17 responses but could be targeted to selectively inhibit proinflammatory Th17 cells.

scholarly journals T Cell-Intrinsic CDK6 Is Dispensable for Anti-Viral and Anti-Tumor Responses In Vivo

2021 ◽  
Vol 12 ◽  
Author(s):  
Klara Klein ◽  
Agnieszka Witalisz-Siepracka ◽  
Dagmar Gotthardt ◽  
Benedikt Agerer ◽  
Felix Locker ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Negative Regulator ◽  
Fine Tuning ◽  
Type I ◽  
Cell Functions ◽  
Intrinsic Loss

The cyclin-dependent kinase 6 (CDK6) regulates the transition through the G1-phase of the cell cycle, but also acts as a transcriptional regulator. As such CDK6 regulates cell survival or cytokine secretion together with STATs, AP-1 or NF-κB. In the hematopoietic system, CDK6 regulates T cell development and promotes leukemia and lymphoma. CDK4/6 kinase inhibitors are FDA approved for treatment of breast cancer patients and have been reported to enhance T cell-mediated anti-tumor immunity. The involvement of CDK6 in T cell functions remains enigmatic. We here investigated the role of CDK6 in CD8+ T cells, using previously generated CDK6 knockout (Cdk6-/-) and kinase-dead mutant CDK6 (Cdk6K43M) knock-in mice. RNA-seq analysis indicated a role of CDK6 in T cell metabolism and interferon (IFN) signaling. To investigate whether these CDK6 functions are T cell-intrinsic, we generated a T cell-specific CDK6 knockout mouse model (Cdk6fl/fl CD4-Cre). T cell-intrinsic loss of CDK6 enhanced mitochondrial respiration in CD8+ T cells, but did not impact on cytotoxicity and production of the effector cytokines IFN-γ and TNF-α by CD8+ T cells in vitro. Loss of CDK6 in peripheral T cells did not affect tumor surveillance of MC38 tumors in vivo. Similarly, while we observed an impaired induction of early responses to type I IFN in CDK6-deficient CD8+ T cells, we failed to observe any differences in the response to LCMV infection upon T cell-intrinsic loss of CDK6 in vivo. This apparent contradiction might at least partially be explained by the reduced expression of Socs1, a negative regulator of IFN signaling, in CDK6-deficient CD8+ T cells. Therefore, our data are in line with a dual role of CDK6 in IFN signaling; while CDK6 promotes early IFN responses, it is also involved in the induction of a negative feedback loop. These data assign CDK6 a role in the fine-tuning of cytokine responses.

scholarly journals T Helper Cell Lineage-Defining Transcription Factors: Potent Targets for Specific GVHD Therapy?

2022 ◽  
Vol 12 ◽  
Author(s):  
Julia Campe ◽  
Evelyn Ullrich
Keyword(s):  
T Cells ◽  
Stem Cell ◽  
T Cell ◽  
Acute Gvhd ◽  
Cell Subset ◽  
Cell Transplant ◽  
T Helper ◽  
Hematopoietic Stem ◽  
Th Cell ◽  
Th17 Differentiation

Allogenic hematopoietic stem cell transplantation (allo-HSCT) represents a potent and potentially curative treatment for many hematopoietic malignancies and hematologic disorders in adults and children. The donor-derived immunity, elicited by the stem cell transplant, can prevent disease relapse but is also responsible for the induction of graft-versus-host disease (GVHD). The pathophysiology of acute GVHD is not completely understood yet. In general, acute GVHD is driven by the inflammatory and cytotoxic effect of alloreactive donor T cells. Since several experimental approaches indicate that CD4 T cells play an important role in initiation and progression of acute GVHD, the contribution of the different CD4 T helper (Th) cell subtypes in the pathomechanism and regulation of the disease is a central point of current research. Th lineages derive from naïve CD4 T cell progenitors and lineage commitment is initiated by the surrounding cytokine milieu and subsequent changes in the transcription factor (TF) profile. Each T cell subtype has its own effector characteristics, immunologic function, and lineage specific cytokine profile, leading to the association with different immune responses and diseases. Acute GVHD is thought to be mainly driven by the Th1/Th17 axis, whereas Treg cells are attributed to attenuate GVHD effects. As the differentiation of each Th subset highly depends on the specific composition of activating and repressing TFs, these present a potent target to alter the Th cell landscape towards a GVHD-ameliorating direction, e.g. by inhibiting Th1 and Th17 differentiation. The finding, that targeting of Th1 and Th17 differentiation appears more effective for GVHD-prevention than a strategy to inhibit Th1 and Th17 cytokines supports this concept. In this review, we shed light on the current advances of potent TF inhibitors to alter Th cell differentiation and consecutively attenuate GVHD. We will focus especially on preclinical studies and outcomes of TF inhibition in murine GVHD models. Finally, we will point out the possible impact of a Th cell subset-specific immune modulation in context of GVHD.

STAT3 Serine Phosphorylation and HDAC Inhibition In CTCL

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 3755-3755 ◽  
Author(s):  
Swati Goel ◽  
Laura K Fogli ◽  
Amy Sun ◽  
Melania Fanok ◽  
Niels Odum ◽  
...  
Keyword(s):  
T Cell ◽  
Mouse Model ◽  
Cell Lines ◽  
Th17 Cells ◽  
Hdac Inhibitors ◽  
Serine Phosphorylation ◽  
Stat3 Signaling ◽  
Stat3 Phosphorylation ◽  
Th17 Differentiation

Abstract Phosphorylation of signal transducer and activator of transcription 3 (STAT3) is essential for cell survival, proliferation and differentiation. STAT3 phosphorylation results from signaling by cytokines and growth factors, and constitutive STAT3 activity is characteristic of a number of human malignancies, including Cutaneous T Cell Lymphoma (CTCL). Furthermore, we now know that STAT3 is also required for the initiation and maintenance of the Th17 differentiation program. Th17 cells are a subset of CD4 T helper cells that have been implicated in chronic inflammatory conditions like rheumatoid arthritis and psoriasis. Mycosis fungoides (MF) and the leukemic variant of this disease, Sezary syndrome (SS), are the most frequently encountered forms of CTCL and in both of these diseases, the cell of origin – as far as the type of Teffector cell involved, has not been defined. Recent results from our laboratory and that of our colleagues have lead us to believe that Th17 cells may either be the cells of origin in CTCL or may act as critical mediators of chronic inflammation that creates a favorable environment for tumor growth in the context of this malignancy. In an effort to elucidate the role of STAT3 as a transforming factor in T cell malignancies, we generated a mouse model wherein T cell specific expression of a hyper-active STAT3 mutant protein (STAT3C) leads to the development of a lymphoproliferative disease that is highly reminiscent of CTCL. We are now taking advantage of this unique mouse model, patient biospecimens and carefully characterized CTCL cell lines to dissect the role of STAT3 signaling cascade in the malignant transformation and maintenance of CTCL. Most recently, our attention has been focused on understanding the mechanism of action of epigenetic therapy in the form of histone deacetylase inhibitors (HDACi), which is highly effective in the treatment of CTCL. We hypothesize that HDAC inhibitors affect the STAT3 mediated Th17 differentiation and thus have clinical efficacy in this disease. In addition to the regulation of chromatin accessibility through the regulation of histone modifications, HDACi have also been implicated in a less conventional mode of protein regulation directly influencing STAT3 serine phosphorylation. To dissect the action of HDACi on malignant cells, we took advantage of CTCL cell lines and cultured these with and without Romidepsin, which is an effective HDAC inhibitor used in clinic. MyLa2059 and PB2B are MF cell lines with skin only phenotype whereas SeAx and SeZ4 are SS cell lines. The cells were cultured for 48 hours with no Romidepsin, 5nm and 50 nm Romidepsin. After 48 hours, cells were fixed and permeabilized using BD fix-perm protocol. Cells were then stained to assess Serine 727 STAT3 and Tyrosine Y705 STAT3 phosphorylation and analyzed using flowcytometry. We found that Romidepsin affected serine phosphorylation exclusively in CTCL cell lines (Figure 1). This leads us to believe that STAT3 serine phosphorylation might play an important role in lymphomagenesis and can act as a potential therapeutic target. The role of serine phosphorylation in the context of STAT3 signaling is hotly debated and we are now attempting to characterize the role of Serine STAT3 phosphorylation in the context of CTCL. We are also hoping to recapitulate these observations in patients' biospecimens collected before and after treatment with HDAC inhibitors. We will also study the role of serine phosphorylation in STAT3 activity in carcinogenesis using our mouse model with phenotypic and pathological characteristics similar to CTCL. We hope that these studies will advance our knowledge about the role that Stat 3 signaling plays in MF/SS malignant transformation and cancer progression and help us develop target specific treatment options for the clinical practice. Disclosures: Hymes: Celgene: Consultancy.

scholarly journals 2406 The microbial-derived short-chain fatty acid butyrate directly and differentially inhibits gut T helper cell subset activation and proliferation

2018 ◽  
Vol 2 (S1) ◽  
pp. 31-32
Author(s):  
Jon Kibbie ◽  
Stephanie Dillon ◽  
Moriah Castleman ◽  
Jay Liu ◽  
Martin McCarter ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cd4 T Cells ◽  
Th17 Cells ◽  
Cell Activation ◽  
Cd4 T Cell ◽  
T Helper ◽  
T Helper Subsets ◽  
Hiv 1

OBJECTIVES/SPECIFIC AIMS: A hallmark of progressive HIV-1 infection is the massive activation and depletion of the gut barrier protective CD4 T helper subsets (Th17 and Th22) in the intestinal mucosa. The loss of these cells is thought to contribute to microbial translocation and systemic immune activation that occurs during chronic infection. In addition to the loss of protective Th subsets, we previously showed that chronically HIV-1 infected individuals have an altered colonic mucosal microbiome, which is in part characterized by a lower relative abundance of bacteria that produce the short-chain fatty acid butyrate in conjunction with increased relative abundance of gram-negative pathobionts. This dysbiosis was linked to markers of mucosal and systemic immune activation in these individuals. Following up on these clinical observations, we sought to understand how a loss of butyrate might contribute to HIV-associated inflammation. Initial studies showed that the addition of butyrate to cultured lamina propria mononuclear cells (LPMC) resulted in decreased pathobiont-driven gut T cell activation, HIV-1 infection levels and production of IL-17 and IFNy. Since the gut barrier protective Th17 and Th22 subsets are preferentially infected and depleted, which is critical to HIV-1 pathogenesis, we wanted to determine the mechanism by which butyrate modulates activation of these important Th subsets in the gut. METHODS/STUDY POPULATION: Total LPMCs or purified LP CD4 T cells were isolated from human jejunal tissue (n=3–6), labeled with CFSE and cultured with TCR/CD28 beads to mimic APC driven T cell activation, with the addition of butyrate at physiologic doses(0–2 mM). Four days after culture, secreted cytokine(IL-17 and IFNy) levels were measured by ELISA. Cells were then short-term (4 hr) mitogenically stimulated (PMA/Ionomycin) in the presence of a golgi transport inhibitor. Total CD4 T cell activation (CD38+/HLA-DR+, CD25+), proliferation (CFSElow), and frequencies of intracellular cytokines were measured by multi-color flow cytometry. Paired t-tests were performed to determine statistical significance. RESULTS/ANTICIPATED RESULTS: Butyrate inhibited LP CD4 T cell activation (p=0.013) and proliferation (p=0.015) within total LPMCs stimulated with TCR/CD28 beads in a dose-dependent manner, with significant activity starting at 0.125 mM. Quantification of total secreted cytokines revealed that butyrate significantly decreased both IL-17 and IFNy production after 4 days of culture at 0.0625 mM and 0.25 mM of butyrate, respectively. Assays using purified LP CD4 T cells demonstrated that butyrate directly decreased LP CD4 T cell activation, proliferation and cytokine production in response to TCR/CD28 stimulation. Studies on specific T helper subsets revealed that butyrate inhibited proliferation of Th17 cells at lower concentrations (IC50:0.147 mM) compared with Th1 (IC50:0.229 mM) and Th22 (IC50:0.258 mM) and Th non-IL-22/IL-17/IFNy producing (IC50:2.14 mM) subsets. In addition, it appeared there was a paradoxical increase of HIV-1 infection levels at lower concentrations of butyrate (0.125 mM). DISCUSSION/SIGNIFICANCE OF IMPACT: The addition of butyrate to activated LP CD4 T cells decreases TCR-mediated activation in a dose-dependent manner, and butyrate acts directly on purified LP CD4 T cell populations independent of other cell populations. Butyrate differentially inhibited the proliferation of Th17, Th1, and Th22 subsets, with Th17 cells being the most sensitive to butyrate but increased the infection levels of all T helper subsets at low concentrations. Further studies are needed to determine the mechanism of butyrate’s actions on LP Th cells and the sensitivity of Th17 cells to the inhibitory effects of butyrate. These results could help direct targeted manipulation of the colonic microbiome of HIV-1 infected individuals to help resolve inflammation and limit the impact of the infection in the gut mucosa and systemically.

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