scholarly journals Differential impact of mammalian target of rapamycin inhibition on CD4+CD25+Foxp3+ regulatory T cells compared with conventional CD4+ T cells

Blood ◽  
2008 ◽  
Vol 111 (1) ◽  
pp. 453-462 ◽  
Author(s):  
Robert Zeiser ◽  
Dennis B. Leveson-Gower ◽  
Elizabeth A. Zambricki ◽  
Neeraja Kambham ◽  
Andreas Beilhack ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Regulatory T Cells ◽  
Mammalian Target Of Rapamycin ◽  
Interleukin 2 ◽  
Mtor Pathway ◽  
Negative Regulator ◽  
Target Of Rapamycin ◽  
Differential Impact ◽  
Mtor Inhibition

Based on their ability to control T-cell homeostasis, Foxp3+CD4+CD25+ regulatory T cells (Tregs) are being considered for treatment of autoimmune disorders and acute graft-versus-host disease (aGVHD). When combining Tregs with the immunosuppressant rapamycin (RAPA), we observed reduced alloreactive conventional T-cell (Tconv) expansion and aGVHD lethality compared with each treatment alone. This synergistic in vivo protection was paralleled by intact expansion of polyclonal Tregs with conserved high FoxP3 expression. In contrast to Tconv, activation of Tregs with alloantigen and interleukin-2 preferentially led to signal transducer and activator of transcription 5 (STAT5) phosphorylation and not phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) pathway activity. Expression of phosphatase and tensin homolog deleted on chromosome 10 (PTEN), a negative regulator of the PI3K/Akt/mTOR pathway, remained high in Tregs but not Tconv during stimulation. Conversely, targeted deletion of PTEN increased susceptibility of Tregs to mTOR inhibition by RAPA. Differential impact of RAPA as a result of reduced usage of the mTOR pathway in Tregs compared with conventional T cells explains the synergistic effect of RAPA and Tregs in aGVHD protection, which has important implications for clinical trials using Tregs.

scholarly journals A2A receptor signaling promotes peripheral tolerance by inducing T-cell anergy and the generation of adaptive regulatory T cells

Blood ◽  
2008 ◽  
Vol 111 (1) ◽  
pp. 251-259 ◽  
Author(s):  
Paul E. Zarek ◽  
Ching-Tai Huang ◽  
Eric R. Lutz ◽  
Jeanne Kowalski ◽  
Maureen R. Horton ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Regulatory T Cells ◽  
Transforming Growth Factor ◽  
Interleukin 2 ◽  
Peripheral Tolerance ◽  
Negative Regulator ◽  
T Cell Anergy ◽  
A2a Receptor ◽  
Cell Anergy

Tissue-derived adenosine, acting via the adenosine A2A receptor (A2AR), is emerging as an important negative regulator of T-cell function. In this report, we demonstrate that A2AR stimulation not only inhibits the generation of adaptive effector T cells but also promotes the induction of adaptive regulatory T cells. In vitro, antigen recognition in the setting of A2AR engagement induces T-cell anergy, even in the presence of costimulation. T cells initially stimulated in the presence of an A2AR agonist fail to proliferate and produce interleukin-2 and interferon (IFN)-γ when rechallenged in the absence of A2AR stimulation. Likewise, in an in vivo model of autoimmunity, tissue-derived adenosine promotes anergy and abrogates tissue destruction. Indeed, A2AR stimulation inhibits interleukin-6 expression while enhancing the production of transforming growth factor-β. Accordingly, treating mice with A2AR agonists not only inhibits Th1 and Th17 effector cell generation but also promotes the generation of Foxp3+ and LAG-3+ regulatory T cells. In this regard, A2AR agonists fail to prevent autoimmunity by LAG-3−/− clonotypic T cells, implicating an important role for LAG-3 in adenosine-mediated peripheral tolerance. Overall, our findings demonstrate that extracellular adenosine stimulates the A2AR to promote long-term T-cell anergy and the generation of adaptive regulatory T cells.

scholarly journals Mammalian target of rapamycin signaling activation patterns in neuroendocrine tumors of the lung

2010 ◽  
Vol 17 (4) ◽  
pp. 977-987 ◽  
Author(s):  
Luisella Righi ◽  
Marco Volante ◽  
Ida Rapa ◽  
Veronica Tavaglione ◽  
Frediano Inzani ◽  
...  
Keyword(s):  
Neuroendocrine Tumors ◽  
Mammalian Target Of Rapamycin ◽  
Mtor Pathway ◽  
Differential Sensitivity ◽  
Initiation Factor ◽  
Target Of Rapamycin ◽  
Low Grade ◽  
Mtor Inhibition ◽  
Signaling Activation ◽  
Activation Status

Among alternative therapeutic strategies in clinically aggressive neuroendocrine tumors (NETs) of the lung, promising results have been obtained in experimental clinical trials with mammalian target of rapamycin (mTOR) inhibitors, though in the absence of a proven mTOR signaling activation status. This study analyzed the expression of phosphorylated mTOR (p-mTOR) and its major targets, the ribosomal p70S6-kinase (S6K) and the eukaryotic initiation factor 4E-binding protein 1 (4EBP1) in a large series of 218 surgically resected, malignant lung NETs, including 24 metastasizing typical carcinoids, 73 atypical carcinoids, 60 large cell neuroendocrine carcinomas (LCNECs), and 61 small cell carcinomas (SCLCs). By immunohistochemistry, low-to-intermediate-grade tumors as compared with high-grade tumors showed higher levels of p-mTOR and phosphorylated S6K (p-S6K) (P<0.001), at variance with phosphorylated 4EBP1 (p-4EBP1), which was mainly expressed in LCNECs and SCLCs (P<0.001). The activated status of mTOR pathway was proved by the strong correlation of p-mTOR with p-S6K and somatostatin receptor(s). Western blot analysis of NET tumor samples confirmed such findings, and differential sensitivity to mTOR inhibition according to mTOR pathway activation characteristics was determined in two lung carcinoid cell lines in vitro. None of the investigated molecules had an impact on survival. However, in low-grade tumors, low p-mTOR expression correlated with lymph node metastases (P=0.016), recurrent disease, and survival (P=0.005). In conclusion, these data demonstrate a differential mTOR activation status in the spectrum of pulmonary NETs, possibly suggesting that mTOR pathway profiling might play a predictive role in candidate patients for mTOR-targeted therapies.

scholarly journals OX40 costimulation and regulatory T cells

Blood ◽  
2007 ◽  
Vol 110 (7) ◽  
pp. 2217-2218
Author(s):  
Jerzy W. Kupiec-Weglinski
Keyword(s):  
T Cells ◽  
T Cell ◽  
Regulatory T Cells ◽  
T Regulatory Cells ◽  
Costimulatory Molecule ◽  
Negative Regulator ◽  
Regulatory Cells ◽  
Activated T Cells

The OX40 T-cell costimulatory molecule, critical for both survival and proliferation of activated T cells, has now been identified as a key negative regulator of Foxp3+ T regulatory cells (Tregs).

scholarly journals Helicobacterpylori-Specific CD4+ CD25high Regulatory T Cells Suppress Memory T-Cell Responses to H. pylori in Infected Individuals

2003 ◽  
Vol 71 (4) ◽  
pp. 1755-1762 ◽  
Author(s):  
Anna Lundgren ◽  
Elisabeth Suri-Payer ◽  
Karin Enarsson ◽  
Ann-Mari Svennerholm ◽  
B. Samuel Lundin
Keyword(s):  
T Cells ◽  
T Cell ◽  
Regulatory T Cells ◽  
Interleukin 2 ◽  
T Cell Responses ◽  
Duodenal Mucosa ◽  
Peptic Ulcers ◽  
Memory Cells ◽  
Cell Responses ◽  
H Pylori

ABSTRACT Helicobacter pylori colonizes the gastric and duodenal mucosa. The infection normally persists for life and causes peptic ulcers and gastric cancer in a subset of infected individuals. We hypothesized that the inability to clear the infection may be a consequence of H. pylori-specific regulatory T cells that actively suppress T-cell responses. Therefore, we characterized the T-cell responses to H. pylori in H. pylori-infected individuals without any subjective symptoms and in uninfected control subjects and investigated the role of regulatory CD4+ CD25high T cells during infection. The stimulation of CD4+ peripheral blood T cells with monocyte-derived dendritic cells pulsed with a membrane preparation of H. pylori resulted in proliferation and gamma interferon production in both infected and uninfected individuals. Sorted memory cells from infected individuals responded less than cells from uninfected subjects, and the unresponsiveness could be abolished by depletion of CD4+ CD25high regulatory T cells or the addition of interleukin 2. Furthermore, CD4+ CD25high T cells suppressed H. pylori-induced responses in cocultures with CD25low/− cells. Tetanus toxoid induced comparable responses in memory cells from infected and uninfected individuals in both the presence and the absence of regulatory T cells, suggesting that the suppression was H. pylori specific. In conclusion, we have shown that H. pylori-infected individuals have impaired memory CD4+ T-cell responses to H. pylori that are linked to the presence of H. pylori-specific regulatory T cells that actively suppress the responses.

Only the CD45RA+ subpopulation of CD4+CD25high T cells gives rise to homogeneous regulatory T-cell lines upon in vitro expansion

Blood ◽  
2006 ◽  
Vol 108 (13) ◽  
pp. 4260-4267 ◽  
Author(s):  
Petra Hoffmann ◽  
Ruediger Eder ◽  
Tina J. Boeld ◽  
Kristina Doser ◽  
Biserka Piseshka ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Regulatory T Cells ◽  
Cell Lines ◽  
Cytotoxic T Lymphocyte ◽  
Interleukin 2 ◽  
Solid Organ ◽  
Cell Therapies ◽  
In Vitro Expansion

Abstract Thymus-derived CD4+CD25+ regulatory T cells suppress autoreactive CD4+ and CD8+ T cells and thereby protect from autoimmunity. In animal models, adoptive transfer of CD4+CD25+ regulatory T cells has been shown to prevent and even cure autoimmune diseases as well as pathogenic alloresponses after solid organ and stem-cell transplantations. We recently described methods for the efficient in vitro expansion of human regulatory T cells for clinical applications. We now demonstrate that only CCR7- and L-selectin (CD62L)–coexpressing cells within expanded CD4+CD25high T cells maintain phenotypic and functional characteristics of regulatory T cells. Further analysis revealed that these cells originate from CD45RA+ naive cells within the CD4+CD25high T-cell compartment, as only this subpopulation homogeneously expressed CD62L, CCR7, cytotoxic T lymphocyte–associated antigen-4 (CTLA-4), and forkhead box P3 (FOXP3), produced no inflammatory cytokines and maintained robust suppressive activity after expansion. In contrast, cell lines derived from CD45RA– memory-type CD4+CD25high T cells lost expression of lymph node homing receptors CCR7 and CD62L, contained interleukin-2 (IL-2) and interferon-γ (IFN-γ) as well as IL-10–secreting cells, showed only moderate suppression and, most importantly, did not maintain FOXP3 expression. Based on these unexpected findings, we suggest that isolation and expansion of CD45RA+ naive CD4+ CD25high T cells is the best strategy for adoptive regulatory T (Treg)–cell therapies.

Initial depletion of regulatory T cells: the missing solution to preserve the immune functions of T lymphocytes designed for cell therapy

Blood ◽  
2006 ◽  
Vol 107 (1) ◽  
pp. 381-388 ◽  
Author(s):  
Mariana Mesel-Lemoine ◽  
Mustapha Cherai ◽  
Sabine Le Gouvello ◽  
Maude Guillot ◽  
Virginie Leclercq ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Regulatory T Cells ◽  
Cell Therapy ◽  
Cell Cultures ◽  
Interleukin 2 ◽  
Culture Conditions ◽  
Immune Functions ◽  
T Cell Therapy ◽  
Cells Cultured

Abstract We investigated the causes of the altered functionality of T cells cultured under conditions designed for cell and gene therapy and the strategies to prevent their defects. We first showed that human T cells cultured for 6 days with anti-CD3 ± anti-CD28 antibodies and interleukin-2 presented a 50% decrease of their proliferative responses to allogeneic or recall antigens. Similarly, day-6 cultured murine T cells completely lost their capacity to reject allogeneic skin grafts and to provoke graft-versus-host disease (GVHD) when infused into irradiated semi-allogeneic mice. Interestingly, injection of higher amounts of cultured T cells restored GVHD induction. Moreover, depletion of CD25+ cells prior to T-cell cultures can prevent these deficiencies both in mice and humans. Therefore, we demonstrated that culture conditions used for T-cell therapy preferentially activated and expanded regulatory T cells (Treg's). Thus, we showed that dividing cells sorted from T-cell cultures strongly suppressed the proliferation of autologous T cells in response to allogeneic stimulation. An increased detection of Foxp3 at mRNA and protein levels in the cultures confirmed the Treg expansion. Overall, we demonstrate that T-cell cultures promote Treg expansion over effector T cells, leading to deleterious immune functions, and that this imbalance can be prevented by an initial depletion of CD25+ cells.

scholarly journals Nuclear factor of activated T-cell c3 inhibition of mammalian target of rapamycin signaling through induction of regulated in development and DNA damage response 1 in human intestinal cells

2012 ◽  
Vol 23 (15) ◽  
pp. 2963-2972 ◽  
Author(s):  
Yuning Zhou ◽  
Qingding Wang ◽  
Zheng Guo ◽  
Heidi L. Weiss ◽  
B. Mark Evers
Keyword(s):  
Cell Differentiation ◽  
T Cell ◽  
Protein Expression ◽  
Promoter Activity ◽  
Mammalian Target Of Rapamycin ◽  
Target Of Rapamycin ◽  
Nuclear Factor ◽  
Mtor Inhibition ◽  
Mrna And Protein Expression ◽  
Activated T Cell

The nuclear factor of activated T-cell (NFAT) proteins are a family of transcription factors (NFATc1–c4) involved in the regulation of cell differentiation. We identified REDD1, a negative regulator of mammalian target of rapamycin (mTOR) through the tuberous sclerosis complex (TSC1/2 complex), as a new molecular target of NFATc3. We show that treatment with a combination of phorbol 12-myristate 13-acetate (PMA) plus ionophore A23187 (Io), which induces NFAT activation, increased REDD1 mRNA and protein expression and inhibited mTOR signaling; pretreatment with the calcineurin inhibitor cyclosporin A (CsA), an antagonist of NFAT signaling, decreased REDD1 induction and mTOR inhibition. Knockdown of NFATc3, not NFATc1, NFATc2, or NFATc4, attenuated PMA/Io-induced REDD1 expression. Treatment with PMA/Io increased REDD1 promoter activity and increased NFATc3 binding to the REDD1 promoter. Overexpression of NFATc3 increased REDD1 mRNA and protein expression and increased PMA/Io-mediated REDD1 promoter activity. Treatment with PMA/Io increased expression of the goblet cell differentiation marker MUC2; these changes were attenuated by pretreatment with CsA or knockdown of REDD1 or NFATc3. Overexpression of NFATc3 increased, while knockdown of TSC2 decreased, MUC2 expression. We provide evidence showing NFATc3 inhibits mTOR via induction of REDD1. Our results suggest a role for the NFATc3/REDD1/TSC2 axis in the regulation of intestinal cell differentiation.

scholarly journals ROG Negatively Regulates T-Cell Activation but Is Dispensable for Th-Cell Differentiation

2005 ◽  
Vol 25 (2) ◽  
pp. 554-562 ◽  
Author(s):  
Bok Yun Kang ◽  
Shi-Chuen Miaw ◽  
I-Cheng Ho
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Target Gene ◽  
Interleukin 2 ◽  
Negative Regulator ◽  
Th2 Cells ◽  
Th Cells ◽  
And Function

ABSTRACT ROG, a transcriptional repressor, is a direct target gene of NF-AT and a putative negative regulator of T-cell activation. In addition, overexpression of ROG suppresses the activity of GATA-3, implying a role of ROG in the differentiation and function of Th cells. Despite these observations, the function of ROG has yet to be confirmed by loss-of-function approaches. Here we report that ROG-deficient T cells are hypersensitive to anti-CD3 stimulation and produce more interleukin-2 (IL-2) due to enhanced NF-κB activity. ROG-deficient dendritic cells also produce more IL-12p40, another NF-κB target gene. However, ROG-deficient Th cells are capable of differentiating into Th1 and Th2 cells, and ROG-deficient mice have no defect in mounting appropriate Th immune responses in vivo. Thus, ROG is dispensable for the differentiation and function of Th cells but serves as a mediator of NF-AT-initiated suppression of NF-κB. Its mechanism of action and its expression pattern are distinct from those of other transcription factors negatively regulating the activation of T cells.

Induction of allopeptide-specific human CD4+CD25+ regulatory T cells ex vivo

Blood ◽  
2003 ◽  
Vol 102 (6) ◽  
pp. 2180-2186 ◽  
Author(s):  
Shuiping Jiang ◽  
Niels Camara ◽  
Giovanna Lombardi ◽  
Robert I. Lechler
Keyword(s):  
T Cells ◽  
T Cell ◽  
Regulatory T Cells ◽  
Cell Line ◽  
Ex Vivo ◽  
Interleukin 2 ◽  
Cell Lineage ◽  
Human Leukocyte ◽  
Regulatory Cells ◽  
Antigen Specificity

Abstract Although CD4+CD25+ regulatory T cells are pivotal in the prevention of autoimmunity and appear to mediate transplantation tolerance, little is known concerning their antigen specificity. Here we describe the induction of a human CD4+CD25+ regulatory T-cell line specific for a defined peptide alloantigen (human leukocyte antigen A2 [HLA-A2] 138-170) by priming purified CD4+CD25+ cells ex vivo. The regulatory cells were anergic and retained their ability to suppress antigen-driven responses of CD4+CD25– cells. They inhibited not only interleukin 2 (IL-2) secretion by CD4+CD25– T cells specific for the same peptide but also direct alloresponse of naive CD4+CD25– T cells stimulated by semiallogeneic dendritic cells (DCs) in the presence of the peptide (“linked suppression”). They also suppressed the response of CD4+ T cells specific for viral and bacterial antigens. The suppressive T-cell line showed sustained high CD25 expression. These findings suggest that peripheral CD4+CD25+ regulatory cells are a precommitted cell lineage from which cells with specificity for non–self-peptides can be selected. This may pave the way for inducing and expanding peptide antigen-specific regulatory T cells ex vivo for cell therapy in transplantation, allergy, and autoimmune disease.

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