scholarly journals FOXP3 Isoforms and Human Regulatory T Cells

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Rebeca Santos ◽  
Baohua Zhou
Keyword(s):  
T Cells ◽  
Regulatory T Cells ◽  
Inflammatory Cytokines ◽  
T Cell Activation ◽  
Cell Activation ◽  
Mononuclear Cells ◽  
Human Peripheral Blood ◽  
Negative Regulator ◽  
Regulatory Function ◽  
Exon 2

Background:  Regulatory T-cells (Tregs) are critical to maintaining immune tolerance, thus prevent autoimmunity and allergic diseases. The master transcription factor FOXP3, expressed in humans as two isoforms through mRNA alternative splicing, controls the development and function of Tregs. However, the functions of the two isoforms remain unclear. We hypothesized that the oligonucleotides, developed by the lab, would efficiently shift FOXP3 to its shorter isoform, lacking exon 2 (FOXP3 ΔE2), which enables us to study how the FOXP3 ΔE2 isoform affects Treg function.      Methods:  Human peripheral blood mononuclear cells (PBMC) were obtained from healthy donors and cultured in the presence of 1 µM isoform-shifting oligonucleotides for three weeks. Expression of the FOXP3 isoforms, CD25, CTLA-4, CD40L, was examined through flow cytometry. Another goal was to study how the FOXP3 ΔE2 isoform shift affects the Treg response to inflammatory cytokines.    Results:  The oligonucleotides are highly effective in shifting the FOXP3 to the FOXP3 ΔE2 isoform. The majority of Tregs express only the FOXP3 ΔE2 isoform after two weeks of culturing in 1 µM oligo and had reduced expression of CD25, which plays a role in Treg differentiation, function, and homeostasis. Tregs display reduced expression of CTLA-4, a negative regulator of T-cell activation, but elevated CD40L, which costimulates and regulates the immune response. The FOXP3 ΔE2 isoform shift also sensitizes the Tregs to proinflammatory cytokine stimulation, allowing for increased IL-4, IL-17A, and IFN-γ production.    Conclusion:  Our studies demonstrate that FOXP3 ΔE2 Tregs are less stable because of the lower CD25 expression and less suppressive as determined by lower CTLA-4 but higher CD40L expression. In the inflammatory environment, the FOXP3 ΔE2 Tregs also produce more inflammatory cytokines, which further reduces their regulatory function. This study establishes an understanding of FOXP3ΔE2 Tregs’ role in autoimmunity and provides a potential novel target to treating autoimmune diseases.     Acknowledgements:  This study was funded, in part, with support from the Immunology and Infectious Diseases Training Program Grant funded, in part by T32 AI 060519 from the National Institutes of Health to RS and NIH AI159804 to BZ.  

A novel negative regulatory function of the phosphoprotein associated with glycosphingolipid-enriched microdomains: blocking Ras activation

Blood ◽  
2007 ◽  
Vol 110 (2) ◽  
pp. 596-625 ◽  
Author(s):  
Michal Smida ◽  
Anita Posevitz-Fejfar ◽  
Vaclav Horejsi ◽  
Burkhart Schraven ◽  
Jonathan A. Lindquist
Keyword(s):  
T Cells ◽  
T Cell Activation ◽  
Cell Activation ◽  
Kinase Activity ◽  
Src Kinase ◽  
Sh2 Domain ◽  
Negative Regulator ◽  
Regulatory Function ◽  
Ras Activation ◽  
Anergic T Cells

Abstract In primary human T cells, anergy induction results in enhanced p59Fyn activity. Because Fyn is the kinase primarily responsible for the phosphorylation of PAG (the phosphoprotein associated with glycosphingolipid-enriched microdomains), which negatively regulates Src-kinase activity by recruiting Csk (the C-terminal Src kinase) to the membrane, we investigated whether anergy induction also affects PAG. Analysis of anergic T cells revealed that PAG is hyperphosphorylated at the Csk binding site, leading to enhanced Csk recruitment and inhibitory tyrosine phosphorylation within Fyn. This together with enhanced phosphorylation of a tyrosine within the SH2 domain of Fyn leads to the formation of a hyperactive conformation, thus explaining the enhanced Fyn kinase activity. In addition, we have also identified the formation of a multiprotein complex containing PAG, Fyn, Sam68, and RasGAP in stimulated T cells. We demonstrate that PAG-Fyn overexpression is sufficient to suppress Ras activation in Jurkat T cells and show that this activity is independent of Csk binding. Thus, in addition to negatively regulating Src family kinases by recruiting Csk, PAG also negatively regulates Ras by recruiting RasGAP to the membrane. Finally, by knocking down PAG, we demonstrate both enhanced Src kinase activity and Ras activation, thereby establishing PAG as an important negative regulator of T-cell activation.

scholarly journals Novel self-amplificatory loop between T cells and tenocytes as a driver of chronicity in tendon disease

2021 ◽  
pp. annrheumdis-2020-219335
Author(s):  
Emma Garcia-Melchor ◽  
Giacomo Cafaro ◽  
Lucy MacDonald ◽  
Lindsay A N Crowe ◽  
Shatakshi Sood ◽  
...  
Keyword(s):  
T Cells ◽  
Cell Migration ◽  
T Cell ◽  
Inflammatory Cytokines ◽  
T Cell Activation ◽  
Cell Activation ◽  
Conditioned Media ◽  
Tissue Remodelling ◽  
Activated T Cells ◽  
T Cell Migration

ObjectivesIncreasing evidence suggests that inflammatory mechanisms play a key role in chronic tendon disease. After observing T cell signatures in human tendinopathy, we explored the interaction between T cells and tendon stromal cells or tenocytes to define their functional contribution to tissue remodelling and inflammation amplification and hence disease perpetuation.MethodsT cells were quantified and characterised in healthy and tendinopathic tissues by flow cytometry (FACS), imaging mass cytometry (IMC) and single cell RNA-seq. Tenocyte activation induced by conditioned media from primary damaged tendon or interleukin-1β was evaluated by qPCR. The role of tenocytes in regulating T cell migration was interrogated in a standard transwell membrane system. T cell activation (cell surface markers by FACS and cytokine release by ELISA) and changes in gene expression in tenocytes (qPCR) were assessed in cocultures of T cells and explanted tenocytes.ResultsSignificant quantitative differences were observed in healthy compared with tendinopathic tissues. IMC showed T cells in close proximity to tenocytes, suggesting tenocyte–T cell interactions. On activation, tenocytes upregulated inflammatory cytokines, chemokines and adhesion molecules implicated in T cell recruitment and activation. Conditioned media from activated tenocytes induced T cell migration and coculture of tenocytes with T cells resulted in reciprocal activation of T cells. In turn, these activated T cells upregulated production of inflammatory mediators in tenocytes, while increasing the pathogenic collagen 3/collagen 1 ratio.ConclusionsInteraction between T cells and tenocytes induces the expression of inflammatory cytokines/chemokines in tenocytes, alters collagen composition favouring collagen 3 and self-amplifies T cell activation via an auto-regulatory feedback loop. Selectively targeting this adaptive/stromal interface may provide novel translational strategies in the management of human tendon disorders.

scholarly journals Endogenous retrovirus-encoded Syncytin-2 contributes to exosome-mediated immunosuppression of T cells†

2019 ◽  
Author(s):  
Adjimon G Lokossou ◽  
Caroline Toudic ◽  
Phuong Trang Nguyen ◽  
Xavier Elisseeff ◽  
Amandine Vargas ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell Activation ◽  
Map Kinases ◽  
Cell Activation ◽  
Mononuclear Cells ◽  
Immune Cell ◽  
Endogenous Retrovirus ◽  
Jurkat Cells ◽  
Peripheral Blood Mononuclear ◽  
Interfering Rna

Abstract Modulation of the activation status of immune cell populations during pregnancy depends on placental villous cytotrophoblast (VCT) cells and the syncytiotrophoblast (STB). Failure in the establishment of this immunoregulatory function leads to pregnancy complications. Our laboratory has been studying Syncytin-2 (Syn-2), an endogenous retroviral protein expressed in placenta and on the surface of placental exosomes. This protein plays an important role not only in STB formation through its fusogenic properties, but also through its immunosuppressive domain (ISD). Considering that Syn-2 expression is importantly reduced in preeclamptic placentas, we were interested in addressing its possible immunoregulatory effects on T cells. Activated Jurkat T cells and peripheral blood mononuclear cells (PBMCs) were treated with monomeric or dimerized version of a control or a Syn-2 ISD peptide. Change in phosphorylation levels of ERK1/2 MAP kinases was selectively noted in Jurkat cells treated with the dimerized ISD peptide. Upon incubation with the dimerized Syn-2 ISD peptide, significant reduction in Th1 cytokine production was further demonstrated by ELISA and Human Th1/Th2 Panel Multi-Analyte Flow Assay. To determine if exosome-associated Syn-2 could also be immunosuppressive placental exosomes were incubated with activated Jurkat and PBMCs. Quantification of Th1 cytokines in the supernatants revealed severe reduction in T cell activation. Interestingly, exosomes from Syn-2-silenced VCT incubated with PBMCs were less suppressive when compared with exosome derived from VCT transfected with control small interfering RNA (siRNA). Our results suggest that Syn-2 is an important immune regulator both locally and systemically, via its association with placental exosomes.

PBMC-07- Stimulation of human peripheral blood mononuclear cells with immobilized anti-CD3 and soluble anti-CD28 antibodies. v1

2021 ◽  
Author(s):  
Alessia Furgiuele ◽  
Massimilano Legnaro ◽  
Alessandra Luini ◽  
Marco Ferrari ◽  
Emanuela Rasini ◽  
...  
Keyword(s):  
T Cell ◽  
T Cell Activation ◽  
Peripheral Blood Mononuclear Cells ◽  
Peripheral Blood ◽  
Cell Activation ◽  
Mononuclear Cells ◽  
Human Peripheral Blood ◽  
Functional Responses ◽  
Peripheral Blood Mononuclear ◽  
Blood Mononuclear Cells

This protocol was designed to activate the lymphocytes T of a population of peripheral blood mononuclear cells (PBMCs), simulating their physiological response to antigen/MHC complex acting on T Cell Receptors-TCR , in order to test their functional responses including cell proliferation and cytokine production. The co-stimulation protocol include: i)anti-CD3 antibody a polyclonal activator specific for invariant framework epitopes on TCR complex (in particular, we use UCHT1 clone an anti-human CD3 antibody that recognizes the ε-chain of CD3 which is used for immobilized option of activation) (http://static.bdbiosciences.com/documents/BD_Tcell_Human_CD3_Activation_Protocol.pdf) ii) anti-CD28 antibody used to cooperate with TCR signals promoting activation of T cells The procedure has been reproduced following the indications contained in the protocol of "EBiooscience" (https://tools.thermofisher.com/content/sfs/manuals/t-cell-activation-in-vitro.pdf). Pilot experiments on PBMC were carried out to determine the best concentrations of anti-CD3 and anti-CD28 to induce optimal proliferation of PBMC and production of cytokines TNF-α and IFN-γ. We found a dose dependent correlation between immobilized anti-CD3 and cells functional responses. The selected amount was 2 µg/mL for both anti-CD3 and anti-CD28 that was the concentration below the maximum response which allows also to test possible modulations by therapeutic agents. References http://static.bdbiosciences.com/documents/BD_Tcell_Human_CD3_Activation_Protocol.pdf https://tools.thermofisher.com/content/sfs/manuals/t-cell-activation-in-vitro.pdf https://www.bdbiosciences.com/ds/pm/tds/555330.pdf https://www.bdbiosciences.com/ds/pm/tds/555726.pdf BEFORE STARTING with this procedure Moreover, work under laminar flow hood when you are processing samples from the beginning to the end of the culture. Make sure you are using,sterile culture mediumand sterile plastic disposable as well.

Effect of CD28 signal transduction on c-Rel in human peripheral blood T cells

1994 ◽  
Vol 14 (12) ◽  
pp. 7933-7942
Author(s):  
R G Bryan ◽  
Y Li ◽  
J H Lai ◽  
M Van ◽  
N R Rice ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Peripheral Blood ◽  
Cell Activation ◽  
Nuclear Translocation ◽  
Human Peripheral Blood ◽  
Interleukin 2 ◽  
Cell Receptor ◽  
Cd28 Costimulation

Optimal T-cell activation requires both an antigen-specific signal delivered through the T-cell receptor and a costimulatory signal which can be delivered through the CD28 molecule. CD28 costimulation induces the expression of multiple lymphokines, including interleukin 2 (IL-2). Because the c-Rel transcription factor bound to and activated the CD28 response element within the IL-2 promoter, we focused our study on the mechanism of CD28-mediated regulation of c-Rel in human peripheral blood T cells. We showed that CD28 costimulation accelerated the kinetics of nuclear translocation of c-Rel (and its phosphorylated form), p50 (NFKB1), and p65 (RelA). The enhanced nuclear translocation of c-Rel correlated with the stimulation of Il-2 production and T-cell proliferation by several distinct anti-CD28 monoclonal antibodies. This is explained at least in part by the long-term downregulation of I kappa B alpha following CD28 signalling as opposed to phorbol myristate acetate alone. Furthermore, we showed that the c-Rel-containing CD28-responsive complex is enhanced by, but not specific to, CD28 costimulation. Our results indicate that c-Rel is one of the transcription factors targeted by CD28 signalling.

Abstract 219: Deficiency of the T Cell Regulator Cbl-B Aggravates Atherosclerosis by Inducing CD8 + T Cell-Mediated Macrophage Death

2017 ◽  
Vol 37 (suppl_1) ◽  
Author(s):  
Tom T Seijkens ◽  
Holger Winkels ◽  
Marion Gijbels ◽  
Jan A Kuivenhoven ◽  
Ljubica Perisic ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Aortic Arch ◽  
T Cell Activation ◽  
Cell Activation ◽  
B Cell Lymphoma ◽  
Negative Regulator ◽  
Atherosclerotic Plaques ◽  
Chow Diet ◽  
Plaque Area

Aims: The E3-ligase CBL-B ( Casitas B-cell Lymphoma-B ) is an important negative regulator of T cell activation that is also expressed in macrophages. T cells and macrophages mediate atherosclerosis, but their regulation in this disease remains largely unknown; thus, we studied the function of CBL-B in atherogenesis. Methods and Results: Here we investigated the effect of CBL-B deficiency in hyperlipidemic Apoe -/- mice in atherosclerosis. At the age of 20 weeks, chow diet-fed Cbl-b -/- Apoe -/- mice showed a significant increase in plaque area in the aortic arch, due to greater macrophage infiltration. Cbl-b -/- Apoe -/- macrophages displayed strong recruitment towards MCP1 and showed an increase in oxidized (ox)LDL uptake. In the aortic root of the same Cbl-b -/- Apoe -/- mice, where more advanced plaques were present than in the aortic arch, plaque area rose by 40%, accompanied by a dramatic change in plaque phenotype. Plaques contained fewer macrophages, had larger necrotic cores, and harboured more CD8 + T cells. The CD8 + T cells of Cbl-b -/- Apoe -/- mice were less susceptible to apoptosis and less resistant to Treg suppression. The increase in CD8 + T cells in the plaque effected greater macrophage apoptosis, resulting in enhanced necrotic core formation. Moreover, CBL-B gene expression was downregulated in human atherosclerotic plaques, and positively correlated with FoxP3 expression, indicating an atheroprotective effect. Conclusion: CBL-B is an important regulator of innate and adaptive immune reactions in atherosclerosis, by mediating macrophage recruitment and activation, CD8 + T cell activation, and CD8 + T cell-induced macrophage death in atherosclerotic plaques.

TREM-1 modulates dendritic cell maturation and dendritic cell–mediated T cell activation induced by ox-LDL

2020 ◽  
Author(s):  
Yunkai Wang ◽  
Jie Wang ◽  
Lu Han ◽  
Yun Li Shen ◽  
Jie Yun You ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
T Cell ◽  
Dendritic Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Human Peripheral Blood ◽  
Dendritic Cell Maturation ◽  
Cell Maturation ◽  
Blood Monocytes

Abstract Background: Triggering receptor expressed on myeloid cells (TREM)-1is identified as a major upstream proatherogenic receptor. However, the cellular processes modulated by TREM-1 in the development of atherosclerosis and plaque destabilization has not been fully elucidated. In this study, we investigated the effects of TREM-1 on dendritic cell maturation and dendritic cell–mediated T-cell activation induced by oxidized low-density lipoprotein (ox-LDL) in atherogenesis. Methods: Human peripheral blood monocytes were differentiated to dendritic cells and stimulated by ox-LDL. Naive autologous T cells were co-cultured with pretreated dendritic cells.The expressionof TREM-1 and the production of inflammatory cytokines were assessed by real-time PCR, western blot and ELISA.The expression of immune factors was determined with FACS to evaluate dendritic cell maturation and T-cell activation. Results: Stimulation with ox-LDL promoted dendritic cell maturation, TREM-1 expression and T-cell activation, and exposure of T cells to ox-LDL-treated dendritic cells induced production of interferon-γ and IL-17. Blocking TREM-1 suppressed dendritic cell maturation with low expression of CD1a, CD40, CD86 and HLA-DR, decreased production of TNF-α, IL-1β, IL-6 and MCP-1, and increased secretion of TGF-β and IL-10. In addition, stimulation of ox-LDL induced miR-155, miR-27, Let-7c and miR-185 expression, whereas inhibition of TREM-1 repressed miRNA-155. Silencing TREM-1 or miRNA-155 increased SOCS1 expression induced by ox-LDL. T cells derived from carotid atherosclerotic plaques or healthy individuals showed similar result patterns. Conclusion: These data suggest that TREM-1 modulates maturation of dendritic cells and activation of plaque T cells induced by ox-LDL, a pivotal player in atherogenesis.

scholarly journals DNAM1 and TIGIT balance the T cell response, with low T cell TIGIT expression corresponding to inflammation in psoriatic disease

2020 ◽  
Author(s):  
M E Jacobs ◽  
J N Pouw ◽  
M A Olde Nordkamp ◽  
T R D J Radstake ◽  
E F A Leijten ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Mononuclear Cells ◽  
Cytokine Production ◽  
Inverse Correlation ◽  
T Cell Response ◽  
Peripheral Blood Mononuclear ◽  
Psoriatic Disease

Abstract Background Signals at the contact site of antigen-presenting cells (APCs) and T cells help orchestrate the adaptive immune response. CD155 on APCs can interact with the stimulatory receptor DNAM1 or inhibitory receptor TIGIT on T cells. The CD155/DNAM1/TIGIT axis is under extensive investigation as immunotherapy target in inflammatory diseases including cancer, chronic infection and autoimmune diseases. We investigated a possible role for CD155/DNAM1/TIGIT signaling in psoriatic disease. Methods By flow cytometry we analyzed peripheral blood mononuclear cells of patients with psoriasis (n=20) or psoriatic arthritis (n=21), and healthy individuals (n=7). We measured CD155, TIGIT and DNAM1 expression on leukocyte subsets and compared activation-induced cytokine production between CD155-positive and -negative APCs. We assessed the effects of TIGIT and DNAM1 blockade on T cell activation, and related the expression of CD155/DNAM1/TIGIT axis molecules to measures of disease activity. Results High CD155 expression associates with TNF production in myeloid and plasmacytoid dendritic cells (DC). In CD1c+ myeloid DC, activation-induced CD155 expression associates with increased HLA-DR expression. CD8 T cells - but not CD4 T cells - express high levels of TIGIT. DNAM1 blockade decreases T cell pro-inflammatory cytokine production, while TIGIT blockade increased T cell proliferation. Finally, T cell TIGIT expression shows an inverse correlation with inflammation biomarkers in psoriatic disease. Conclusion CD155 is increased on pro-inflammatory APCs, while the receptors DNAM1 and TIGIT expressed on T cells balance the inflammatory response by T cells. In psoriatic disease, low TIGIT expression on T cells is associated with systemic inflammation.

scholarly journals Induction of Cytotoxic T Lymphocyte Antigen 4 (Ctla-4) Restricts Clonal Expansion of Helper T Cells

2001 ◽  
Vol 194 (7) ◽  
pp. 893-902 ◽  
Author(s):  
Alden M. Doyle ◽  
Alan C. Mullen ◽  
Alejandro V. Villarino ◽  
Anne S. Hutchins ◽  
Frances A. High ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell Activation ◽  
T Lymphocyte ◽  
Cd4 T Cells ◽  
Cell Activation ◽  
Cytotoxic T Lymphocyte ◽  
Clonal Expansion ◽  
Negative Regulator ◽  
Lymphocyte Antigen ◽  
Cell Divisions

Cytotoxic T lymphocyte antigen (CTLA)-4 plays an essential role in immunologic homeostasis. How this negative regulator of T cell activation executes its functions has remained controversial. We now provide evidence that CTLA-4 mediates a cell-intrinsic counterbalance to restrict the clonal expansion of proliferating CD4+ T cells. The regulation of CTLA-4 expression and function ensures that, after ∼3 cell divisions of expansion, most progeny will succumb to either proliferative arrest or death over the ensuing three cell divisions. The quantitative precision of the counterbalance hinges on the graded, time-independent induction of CTLA-4 expression during the first three cell divisions. In contrast to the limits imposed on unpolarized cells, T helper type 1 (Th1) and Th2 effector progeny may be rescued from proliferative arrest by interleukin (IL)-12 and IL-4 signaling, respectively, allowing appropriately stimulated progeny to proceed to the stage of tissue homing. These results suggest that the cell-autonomous regulation of CTLA-4 induction may be a central checkpoint of clonal expansion of CD4+ T cells, allowing temporally and spatially restricted growth of progeny to be dictated by the nature of the threat posed to the host.

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