scholarly journals CD4+ T-Cell Activation Prompts Suppressive Function by Extracellular Vesicle-Associated MicroRNAs

2021 ◽  
Vol 9 ◽  
Author(s):  
Dario Di Silvestre ◽  
Silvia Garavelli ◽  
Claudio Procaccini ◽  
Francesco Prattichizzo ◽  
Giulia Passignani ◽  
...  
Keyword(s):  
T Cell ◽  
T Cell Activation ◽  
Transcriptional Repression ◽  
Cell Activation ◽  
Cell Activity ◽  
Protein Translation ◽  
Cell Receptor ◽  
Effector Function ◽  
Energy Utilization ◽  
Messenger Rnas

MicroRNAs (miRNAs), small non-coding molecules targeting messenger RNAs and inhibiting protein translation, modulate key biological processes, including cell growth and development, energy utilization, and homeostasis. In particular, miRNAs control the differentiation, survival, and activation of CD4+ T conventional (Tconv) cells, key players of the adaptive immunity, and regulate the physiological response to infections and the pathological loss of immune homeostasis in autoimmunity. Upon T-cell receptor (TCR) stimulation, the described global miRNA quantitative decrease occurring in T cells is believed to promote the acquisition of effector functions by relaxing the post-transcriptional repression of genes associated with proliferation and cell activity. MiRNAs were initially thought to get downregulated uniquely by intracellular degradation; on the other hand, miRNA secretion via extracellular vesicles (EVs) represents an additional mechanism of rapid downregulation. By focusing on molecular interactions by means of graph theory, we have found that miRNAs released by TCR-stimulated Tconv cells are significantly enriched for targeting transcripts upregulated upon stimulation, including those encoding for crucial proteins associated with Tconv cell activation and function. Based on this computational approach, we present our perspective based on the following hypothesis: a stimulated Tconv cell will release miRNAs targeting genes associated with the effector function in the extracellular space in association with EVs, which will thus possess a suppressive potential toward other Tconv cells in the paracrine environment. We also propose possible future directions of investigation aimed at taking advantage of these phenomena to control Tconv cell effector function in health and autoimmunity.

scholarly journals Suboptimal T-cell receptor signaling compromises protein translation, ribosome biogenesis, and proliferation of mouse CD8 T cells

2017 ◽  
Vol 114 (30) ◽  
pp. E6117-E6126 ◽  
Author(s):  
Thomas C. J. Tan ◽  
John Knight ◽  
Thomas Sbarrato ◽  
Kate Dudek ◽  
Anne E. Willis ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Receptor ◽  
T Cell Activation ◽  
Ribosome Biogenesis ◽  
Cell Activation ◽  
Mrna Translation ◽  
Protein Translation ◽  
Cell Receptor ◽  
Tcr Signaling

Global transcriptomic and proteomic analyses of T cells have been rich sources of unbiased data for understanding T-cell activation. Lack of full concordance of these datasets has illustrated that important facets of T-cell activation are controlled at the level of translation. We undertook translatome analysis of CD8 T-cell activation, combining polysome profiling and microarray analysis. We revealed that altering T-cell receptor stimulation influenced recruitment of mRNAs to heavy polysomes and translation of subsets of genes. A major pathway that was compromised, when TCR signaling was suboptimal, was linked to ribosome biogenesis, a rate-limiting factor in both cell growth and proliferation. Defective TCR signaling affected transcription and processing of ribosomal RNA precursors, as well as the translation of specific ribosomal proteins and translation factors. Mechanistically, IL-2 production was compromised in weakly stimulated T cells, affecting the abundance of Myc protein, a known regulator of ribosome biogenesis. Consequently, weakly activated T cells showed impaired production of ribosomes and a failure to maintain proliferative capacity after stimulation. We demonstrate that primary T cells respond to various environmental cues by regulating ribosome biogenesis and mRNA translation at multiple levels to sustain proliferation and differentiation.

scholarly journals LncRNAs Target Ferroptosis-Related Genes and Impair Activation of CD4+ T Cell in Gastric Cancer

2021 ◽  
Vol 9 ◽  
Author(s):  
Fuwen Yao ◽  
Yongqiang Zhan ◽  
Zuhui Pu ◽  
Ying Lu ◽  
Jiao Chen ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
T Cell ◽  
Tumor Microenvironment ◽  
T Cell Activation ◽  
Cell Activation ◽  
Immune Cell ◽  
Cell Activity ◽  
Cell Receptor ◽  
Cell Infiltration ◽  
Poor Overall Survival

Gastric cancer (GC) is a malignant disease of the digestive tract and a life-threatening disease worldwide. Ferroptosis, an iron-dependent cell death caused by lipid peroxidation, is reported to be highly correlated with gastric tumorigenesis and immune cell activity. However, the underlying relationship between ferroptosis and the tumor microenvironment in GC and potential intervention strategies have not been unveiled. In this study, we profiled the transcriptome and prognosis data of ferroptosis-related genes (FRGs) in GC samples of the TCGA-STAD dataset. The infiltrating immune cells in GC were estimated using the CIBERSORT and XCELL algorithms. We found that the high expression of the hub FRGs (MYB, PSAT1, TP53, and LONP1) was positively correlated with poor overall survival in GC patients. The results were validated in an external GC cohort (GSE62254). Further immune cell infiltration analysis revealed that CD4+ T cells were the major infiltrated cells in the tumor microenvironment of GC. Moreover, the hub FRGs were significantly positively correlated with activated CD4+ T cell infiltration, especially Th cells. The gene features in the high-FRG score group were enriched in cell division, DNA repair, protein folding, T cell receptor, Wnt and NIK/NF-kappaB signaling pathways, indicating that the hub FRGs may mediate CD4+ T cell activation by these pathways. In addition, an upstream transcriptional regulation network of the hub FRGs by lncRNAs was also developed. Three lncRNAs (A2M-AS1, C2orf27A, and ZNF667-AS1) were identified to be related to the expression of the hub FRGs. Collectively, these results showed that lncRNA A2M-AS1, C2orf27A, and ZNF667-AS1 may target the hub FRGs and impair CD4+ T cell activation, which finally leads to poor prognosis of GC. Effective interventions for the above lncRNAs and the hub FRGs can help promote CD4+ T cell activation in GC patients and improve the efficacy of immunotherapy. These findings provide a novel idea of GC immunotherapy and hold promise for future clinical application.

Sphingomyelin breakdown in T cells: role in activation, effector functions and immunoregulation

2015 ◽  
Vol 396 (6-7) ◽  
pp. 749-758 ◽  
Author(s):  
Niklas Beyersdorf ◽  
Nora Müller
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Receptor ◽  
T Cell Activation ◽  
Cell Activation ◽  
Immunological Synapse ◽  
Cell Activity ◽  
Cell Receptor ◽  
Cell Mediated Immunity ◽  
Functional Responses

Abstract Host T cell activation, a key step in obtaining adaptive immunity against pathogens, is initiated by the binding of the T cell receptor to a foreign antigenic peptide presented by the major histocompatibility complex on the surface of an antigen-presenting cell and, consequently, formation of an immunological synapse. Within the immunological synapse, the engagement of the T cell receptor in cooperation with simultaneous ligation of co-stimulatory molecules induces a precisely organized cascade of signaling events and pathways that regulate clonal expansion and differentiation of naïve T cells into effector T cells contributing to pathogen clearance. The biochemical changes that underlie T cell activation and differentiation, however, not only involve proteins but also lipids. In particular, catabolic cleavage of sphingomyelin generating ceramide can substantially influence functional responses in cells of the immune system. Changes in sphingomyelin and ceramide content have been reported to directly impact on membrane physiology, thus modifying signal transmission and interfering with diverse aspects of T cell activity. In this review we will focus on sphingomyelin breakdown/ceramide generation in T cells with regard to their function and development of T cell-mediated immunity.

scholarly journals Quantitative phosphoproteomic analysis reveals involvement of PD-1 in multiple T cell functions

2020 ◽  
Vol 295 (52) ◽  
pp. 18036-18050
Author(s):  
Anna S. Tocheva ◽  
Michael Peled ◽  
Marianne Strazza ◽  
Kieran R. Adam ◽  
Shalom Lerrer ◽  
...  
Keyword(s):  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Synapse Formation ◽  
Significant Proportion ◽  
T Cell Responses ◽  
Protein Translation ◽  
Cell Receptor ◽  
Cell Functions ◽  
Cell Responses

Programmed cell death protein 1 (PD-1) is a critical inhibitory receptor that limits excessive T cell responses. Cancer cells have evolved to evade these immunoregulatory mechanisms by upregulating PD-1 ligands and preventing T cell–mediated anti-tumor responses. Consequently, therapeutic blockade of PD-1 enhances T cell–mediated anti-tumor immunity, but many patients do not respond and a significant proportion develop inflammatory toxicities. To improve anti-cancer therapy, it is critical to reveal the mechanisms by which PD-1 regulates T cell responses. We performed global quantitative phosphoproteomic interrogation of PD-1 signaling in T cells. By complementing our analysis with functional validation assays, we show that PD-1 targets tyrosine phosphosites that mediate proximal T cell receptor signaling, cytoskeletal organization, and immune synapse formation. PD-1 ligation also led to differential phosphorylation of serine and threonine sites within proteins regulating T cell activation, gene expression, and protein translation. In silico predictions revealed that kinase/substrate relationships engaged downstream of PD-1 ligation. These insights uncover the phosphoproteomic landscape of PD-1–triggered pathways and reveal novel PD-1 substrates that modulate diverse T cell functions and may serve as future therapeutic targets. These data are a useful resource in the design of future PD-1–targeting therapeutic approaches.

scholarly journals SIRT5 Contributes to Colorectal Cancer Growth by Regulating T Cell Activity

2020 ◽  
Vol 2020 ◽  
pp. 1-17
Author(s):  
Ke Wang ◽  
Zuojian Hu ◽  
Cuiping Zhang ◽  
Lujie Yang ◽  
Li Feng ◽  
...  
Keyword(s):  
T Cell ◽  
Tumor Microenvironment ◽  
T Cell Activation ◽  
Metabolic Regulation ◽  
Cell Activation ◽  
Cell Activity ◽  
Cell Receptor ◽  
Treg Cells ◽  
T Helper 1 ◽  
Colorectal Tumorigenesis

Over the past several years, SIRT5 has attracted considerable attention in metabolic regulation. However, the function of SIRT5 in tumorigenesis by regulating tumor microenvironment is poorly understood. In this work, we found that Sirt5 knockout mice were resistant to AOM and DSS-induced colitis-associated colorectal tumorigenesis and the level of IFN-γ in their tumor microenvironment was higher. Additionally, proteome and network analysis revealed that SIRT5 was important in the T cell receptor signaling pathway. Furthermore, we determined that a deficiency of Sirt5 induced stronger T cell activation and demonstrated that SIRT5 played a pivotal role in regulating the differentiation of CD4+ regulatory T (Treg) cells and T helper 1 (Th1) cells. An imbalance in the lineages of immunosuppressive Treg cells and the inflammatory Th1 subsets of helper T cells leads to the development of colon cancer. Our results revealed a regulatory role of SIRT5 in T cell activation and colorectal tumorigenesis.

scholarly journals PD-1 suppresses TCR-CD8 cooperativity during T-cell antigen recognition

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Kaitao Li ◽  
Zhou Yuan ◽  
Jintian Lyu ◽  
Eunseon Ahn ◽  
Simon J. Davis ◽  
...  
Keyword(s):  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Clinical Success ◽  
Clinical Intervention ◽  
Cell Receptor ◽  
Cell Interaction ◽  
Antigen Recognition ◽  
Inhibitory Function ◽  
Src Homology

AbstractDespite the clinical success of blocking its interactions, how PD-1 inhibits T-cell activation is incompletely understood, as exemplified by its potency far exceeding what might be predicted from its affinity for PD-1 ligand-1 (PD-L1). This may be partially attributed to PD-1’s targeting the proximal signaling of the T-cell receptor (TCR) and co-stimulatory receptor CD28 via activating Src homology region 2 domain-containing phosphatases (SHPs). Here, we report PD-1 signaling regulates the initial TCR antigen recognition manifested in a smaller spreading area, fewer molecular bonds formed, and shorter bond lifetime of T cell interaction with peptide-major histocompatibility complex (pMHC) in the presence than absence of PD-L1 in a manner dependent on SHPs and Leukocyte C-terminal Src kinase. Our results identify a PD-1 inhibitory mechanism that disrupts the cooperative TCR–pMHC–CD8 trimolecular interaction, which prevents CD8 from augmenting antigen recognition, explaining PD-1’s potent inhibitory function and its value as a target for clinical intervention.

scholarly journals Ca2+/Calmodulin-Dependent Protein Kinase II Is a Modulator of CARMA1-Mediated NF-κB Activation

2006 ◽  
Vol 26 (14) ◽  
pp. 5497-5508 ◽  
Author(s):  
Kazuhiro Ishiguro ◽  
Todd Green ◽  
Joseph Rapley ◽  
Heather Wachtel ◽  
Cosmas Giallourakis ◽  
...  
Keyword(s):  
T Cell ◽  
Protein Kinase ◽  
T Cell Activation ◽  
Cell Activation ◽  
Cell Receptor ◽  
Tcr Signaling ◽  
Dependent Protein Kinase ◽  
Immune Synapse ◽  
Protein Kinase Ii ◽  
Dependent Protein

ABSTRACT CARMA1 is a central regulator of NF-κB activation in lymphocytes. CARMA1 and Bcl10 functionally interact and control NF-κB signaling downstream of the T-cell receptor (TCR). Computational analysis of expression neighborhoods of CARMA1-Bcl10MALT 1 for enrichment in kinases identified calmodulin-dependent protein kinase II (CaMKII) as an important component of this pathway. Here we report that Ca2+/CaMKII is redistributed to the immune synapse following T-cell activation and that CaMKII is critical for NF-κB activation induced by TCR stimulation. Furthermore, CaMKII enhances CARMA1-induced NF-κB activation. Moreover, we have shown that CaMKII phosphorylates CARMA1 on Ser109 and that the phosphorylation facilitates the interaction between CARMA1 and Bcl10. These results provide a novel function for CaMKII in TCR signaling and CARMA1-induced NF-κB activation.

scholarly journals A new HLA-linked T cell membrane molecule, related to the beta chain of the clonotypic receptor, is associated with T3.

1986 ◽  
Vol 164 (2) ◽  
pp. 458-473 ◽  
Author(s):  
Y Bushkin ◽  
D N Posnett ◽  
B Pernis ◽  
C Y Wang
Keyword(s):  
T Cell ◽  
T Cell Activation ◽  
Functional Role ◽  
Cell Activation ◽  
Cell Receptor ◽  
Leukemia Cells ◽  
Alpha Beta ◽  
Beta 2 Microglobulin ◽  
T Cell Membrane ◽  
Membrane Molecule

The 38 kD molecule is noncovalently associated with beta 2 microglobulin (beta 2m)-free HLA heavy chain-like molecule, and thus forms a second heterodimer distinct from the clonotypic alpha/beta T cell receptor expressed by the same clone of leukemia cells. This second heterodimer (38 kD/HLA) is variably expressed and appears to be associated with the T3 molecule. We suggest, therefore, that it has a functional role in T cell activation.

scholarly journals T cell receptor zeta/CD3-p59fyn(T)-associated p120/130 binds to the SH2 domain of p59fyn(T).

1993 ◽  
Vol 178 (6) ◽  
pp. 2107-2113 ◽  
Author(s):  
A J da Silva ◽  
O Janssen ◽  
C E Rudd
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Receptor ◽  
T Cell Activation ◽  
Intracellular Signaling ◽  
Cell Activation ◽  
Cell Receptor ◽  
Sh2 Domain ◽  
T Complex

Intracellular signaling from the T cell receptor (TCR)zeta/CD3 complex is likely to be mediated by associated protein tyrosine kinases such as p59fyn(T), ZAP-70, and the CD4:p56lck and CD8:p56lck coreceptors. The nature of the signaling cascade initiated by these kinases, their specificities, and downstream targets remain to be elucidated. The TCR-zeta/CD3:p59fyn(T) complex has previously been noted to coprecipitate a 120/130-kD doublet (p120/130). This intracellular protein of unknown identity associates directly with p59fyn(T) within the receptor complex. In this study, we have shown that this interaction with p120/130 is specifically mediated by the SH2 domain (not the fyn-SH3 domain) of p59fyn(T). Further, based on the results of in vitro kinase assays, p120/130 appears to be preferentially associated with p59fyn(T) in T cells, and not with p56lck. Antibody reprecipitation studies identified p120/130 as a previously described 130-kD substrate of pp60v-src whose function and structure is unknown. TCR-zeta/CD3 induced activation of T cells augmented the tyrosine phosphorylation of p120/130 in vivo as detected by antibody and GST:fyn-SH2 fusion proteins. p120/130 represents the first identified p59fyn(T):SH2 binding substrate in T cells, and as such is likely to play a key role in the early events of T cell activation.

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