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

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.

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O22 Assessing the role of tendon T cell interactions in the development of chronicity in PsA

Rheumatology ◽

10.1093/rheumatology/keaa110.021 ◽

2020 ◽

Vol 59 (Supplement_2) ◽

Author(s):

Emma Garcia-Melchor ◽

Giacomo Cafaro ◽

Shatakshi Sood ◽

Lindsay A. N Crowe ◽

Michael McLean ◽

...

Keyword(s):

T Cells ◽

Cell Migration ◽

T Cell ◽

T Cell Activation ◽

Conditioned Media ◽

Activated T Cells ◽

Stromal Compartment ◽

T Cell Migration ◽

The Impact

Abstract Background Mechanical stress or damage is a well-known inducer of inflammation in both psoriasis and psoriatic arthritis (PsA). The occurrence of microtrauma at enthesial sites, areas subjected to high mechanic stress, could explain the development of local inflammation (enthesitis) that further extends to the synovial tissue through what it is known synovio-entheseal complex. Current treatment strategies mainly target the immune compartment, however there is growing evidence for the role of the stroma in the development of chronic inflammation. Increasing attention has focused on the interaction between the stroma and immune system and its role in the initiation/development of tissue inflammatory chronicity. Our hypothesis is that stromal cells in the tendon or tenocytes, once activated, are able to recruit and activate T cells into the tendon, which in turn may have an effect on the stroma, altogether leading to chronicity. Methods We assessed the effect of damage on healthy tenocytes after stimulation with conditioned media from tendon explants or IL-1β by qPCR and ELISA. A transwell membrane system was used to test the impact of conditioned media from tenocytes on T cell migration. T cells and tenocytes were co-cultured with or without the presence of a transwell membrane to quantify T cell activation (CD69 by FACS and IFN-γ by ELISA). Changes in gene expression on tenocytes after co-culture with activated T cells were analysed by qPCR. Results In the presence of damage, tenocytes upregulated inflammatory cytokines (IL-1β, IL-6), chemokines (IL-8, CCL2, CCL5, CXCL10) and adhesion molecules (ICAM-1). Of interest, we observed an upregulation of CCL20, both at transcript and protein level. Conditioned media from tenocytes induced T cell migration, especially after stimulation. Co-culture of tenocytes and T cells resulted in contact dependant activation of T cells. These activated T cells also had an effect on tenocytes, further upregulating the production of inflammatory mediators. Conclusion These results support the role of the tendon stromal compartment in the recruitment and activation of T cells, creating a feedback loop that could be involved in the maintenance of the inflammatory process and the development of chronicity in the context of PsA. Moreover, the production of CCL20 by tenocytes after damage could explain the preferential recruitment of Th17 or gamma delta T cells into the tendon. We are further investigating the mechanisms that govern this relationship that could be targeted therapeutically in the future. Disclosures E. Garcia-Melchor None. G. Cafaro None. S. Sood None. L.A.N. Crowe None. M. McLean None. I.B. McInnes None. M. Akbar None. N.L. Millar None.

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Optical Control of CD8+ T Cell Metabolism and Effector Functions

Frontiers in Immunology ◽

10.3389/fimmu.2021.666231 ◽

2021 ◽

Vol 12 ◽

Author(s):

Andrea M. Amitrano ◽

Brandon J. Berry ◽

Kihong Lim ◽

Kyun-Do Kim ◽

Richard E. Waugh ◽

...

Keyword(s):

T Cells ◽

Cell Migration ◽

Membrane Potential ◽

T Cell ◽

T Cell Activation ◽

Mitochondrial Membrane ◽

Cell Activation ◽

Cell Metabolism ◽

Effector Function ◽

T Cell Migration

Although cancer immunotherapy is effective against hematological malignancies, it is less effective against solid tumors due in part to significant metabolic challenges present in the tumor microenvironment (TME), where infiltrated CD8+ T cells face fierce competition with cancer cells for limited nutrients. Strong metabolic suppression in the TME is often associated with impaired T cell recruitment to the tumor site and hyporesponsive effector function via T cell exhaustion. Increasing evidence suggests that mitochondria play a key role in CD8+ T cell activation, effector function, and persistence in tumors. In this study, we showed that there was an increase in overall mitochondrial function, including mitochondrial mass and membrane potential, during both mouse and human CD8+ T cell activation. CD8+ T cell mitochondrial membrane potential was closely correlated with granzyme B and IFN-γ production, demonstrating the significance of mitochondria in effector T cell function. Additionally, activated CD8+ T cells that migrate on ICAM-1 and CXCL12 consumed significantly more oxygen than stationary CD8+ T cells. Inhibition of mitochondrial respiration decreased the velocity of CD8+ T cell migration, indicating the importance of mitochondrial metabolism in CD8+ T cell migration. Remote optical stimulation of CD8+ T cells that express our newly developed “OptoMito-On” successfully enhanced mitochondrial ATP production and improved overall CD8+ T cell migration and effector function. Our study provides new insight into the effect of the mitochondrial membrane potential on CD8+ T cell effector function and demonstrates the development of a novel optogenetic technique to remotely control T cell metabolism and effector function at the target tumor site with outstanding specificity and temporospatial resolution.

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NFATc3 regulates the transcription of genes involved in T-cell activation and angiogenesis

Blood ◽

10.1182/blood-2010-12-322701 ◽

2011 ◽

Vol 118 (3) ◽

pp. 795-803 ◽

Cited By ~ 31

Author(s):

Katia Urso ◽

Arantzazu Alfranca ◽

Sara Martínez-Martínez ◽

Amelia Escolano ◽

Inmaculada Ortega ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

T Cell Activation ◽

Cell Activation ◽

Target Genes ◽

Gene Knockout ◽

Activated T Cells ◽

Knock Down ◽

And Function

Abstract The nuclear factor of activated T cells (NFAT) family of transcription factors plays important roles in many biologic processes, including the development and function of the immune and vascular systems. Cells usually express more than one NFAT member, raising the question of whether NFATs play overlapping roles or if each member has selective functions. Using mRNA knock-down, we show that NFATc3 is specifically required for IL2 and cyclooxygenase-2 (COX2) gene expression in transformed and primary T cells and for T-cell proliferation. We also show that NFATc3 regulates COX2 in endothelial cells, where it is required for COX2, dependent migration and angiogenesis in vivo. These results indicate that individual NFAT members mediate specific functions through the differential regulation of the transcription of target genes. These effects, observed on short-term suppression by mRNA knock-down, are likely to have been masked by compensatory effects in gene-knockout studies.

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T cells: a dedicated effector kinase pathways for every trait?

Biochemical Journal ◽

10.1042/bcj20210006 ◽

2021 ◽

Vol 478 (6) ◽

pp. 1303-1307

Author(s):

Kriti Bahl ◽

Jeroen P. Roose

Keyword(s):

T Cells ◽

T Cell ◽

T Cell Activation ◽

Cell Activation ◽

Cell Receptor ◽

Spectrometric Analysis ◽

Activated T Cells ◽

Biological Responses ◽

Extracellular Signal ◽

Differentiation And Proliferation

Signaling pathways play critical roles in regulating the activation of T cells. Recognition of foreign peptide presented by MHC to the T cell receptor (TCR) triggers a signaling cascade of proximal kinases and adapter molecules that lead to the activation of Effector kinase pathways. These effector kinase pathways play pivotal roles in T cell activation, differentiation, and proliferation. RNA sequencing-based methods have provided insights into the gene expression programs that support the above-mentioned cell biological responses. The proteome is often overlooked. A recent study by Damasio et al. [Biochem. J. (2021) 478, 79–98. doi:10.1042/BCJ20200661] focuses on characterizing the effect of extracellular signal-regulated kinase (ERK) on the remodeling of the proteome of activated CD8+ T cells using Mass spectrometric analysis. Surprisingly, the Effector kinase ERK pathway is responsible for only a select proportion of the proteome that restructures during T cell activation. The primary targets of ERK signaling are transcription factors, cytokines, and cytokine receptors. In this commentary, we discuss the recent findings by Damasio et al. [Biochem. J. (2021) 478, 79–98. doi:10.1042/BCJ20200661] in the context of different Effector kinase pathways in activated T cells.

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SLFN2 protection of tRNAs from stress-induced cleavage is essential for T cell–mediated immunity

Science ◽

10.1126/science.aba4220 ◽

2021 ◽

Vol 372 (6543) ◽

pp. eaba4220 ◽

Cited By ~ 1

Author(s):

Tao Yue ◽

Xiaoming Zhan ◽

Duanwu Zhang ◽

Ruchi Jain ◽

Kuan-wen Wang ◽

...

Keyword(s):

Oxidative Stress ◽

T Cells ◽

T Cell ◽

T Cell Activation ◽

Cell Activation ◽

Interleukin 2 ◽

Cell Receptor ◽

Cell Mediated Immunity ◽

Activated T Cells ◽

Granule Formation

Reactive oxygen species (ROS) increase in activated T cells because of metabolic activity induced to support T cell proliferation and differentiation. We show that these ROS trigger an oxidative stress response that leads to translation repression. This response is countered by Schlafen 2 (SLFN2), which directly binds transfer RNAs (tRNAs) to protect them from cleavage by the ribonuclease angiogenin. T cell–specific SLFN2 deficiency results in the accumulation of tRNA fragments, which inhibit translation and promote stress-granule formation. Interleukin-2 receptor β (IL-2Rβ) and IL-2Rγ fail to be translationally up-regulated after T cell receptor stimulation, rendering SLFN2-deficient T cells insensitive to interleukin-2’s mitogenic effects. SLFN2 confers resistance against the ROS-mediated translation-inhibitory effects of oxidative stress normally induced by T cell activation, permitting the robust protein synthesis necessary for T cell expansion and immunity.

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Extracellular signal-regulated kinase (ERK) pathway control of CD8+ T cell differentiation

10.1101/2020.08.18.255711 ◽

2020 ◽

Author(s):

Marcos P. Damasio ◽

Julia M. Marchingo ◽

Laura Spinelli ◽

Doreen A. Cantrell ◽

Andrew J.M. Howden

Keyword(s):

T Cells ◽

T Cell ◽

T Cell Activation ◽

Cell Activation ◽

Antigen Receptor ◽

T Cell Differentiation ◽

Signalling Pathways ◽

Activated T Cells ◽

Transcriptional Reprogramming ◽

Extracellular Signal

SummaryThe integration of multiple signalling pathways that co-ordinate T cell metabolism and transcriptional reprogramming is required to drive T cell differentiation and proliferation. One key T cell signalling module is mediated by extracellular signal-regulated kinases (ERKs) which are activated in response to antigen receptor engagement. The activity of ERKs is often used to report antigen receptor occupancy but the full details of how ERKs control T cell activation is not understood. Accordingly, we have used mass spectrometry to explore how ERK signalling pathways control antigen receptor driven proteome restructuring in CD8 + T cells to gain insights about the biological processes controlled by ERKs in primary lymphocytes. Quantitative analysis of >8000 proteins identified only 900 ERK regulated proteins in activated CD8+ T cells. The data identify both positive and negative regulatory roles for ERKs during T cell activation and reveal that ERK signalling primarily controls the repertoire of transcription factors, cytokines and cytokine receptors expressed by activated T cells. The ERKs thus drive the transcriptional reprogramming of activated T cells and the ability of T cells to communicate with external immune cues.

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Distinct cellular immune profiles in the airways and blood of critically ill patients with COVID-19

10.1101/2020.10.29.360586 ◽

2020 ◽

Author(s):

Anno Saris ◽

Tom D.Y. Reijnders ◽

Esther J. Nossent ◽

Alex R. Schuurman ◽

Jan Verhoeff ◽

...

Keyword(s):

Immune Response ◽

T Cells ◽

T Cell ◽

T Cell Activation ◽

Peripheral Blood ◽

Cell Activation ◽

Effector Memory ◽

Activated T Cells ◽

Immune Profile ◽

Prolonged Icu Stay

AbstractOur understanding of the coronavirus disease-19 (COVID-19) immune response is almost exclusively derived from studies that examined blood. To gain insight in the pulmonary immune response we analysed BALF samples and paired blood samples from 17 severe COVID-19 patients. Macrophages and T cells were the most abundant cells in BALF. In the lungs, both CD4 and CD8 T cells were predominantly effector memory cells and expressed higher levels of the exhaustion marker PD-1 than in peripheral blood. Prolonged ICU stay associated with a reduced proportion of activated T cells in peripheral blood and even more so in BALF. T cell activation in blood, but not in BALF, was higher in fatal COVID-19 cases. Increased levels of inflammatory mediators were more pronounced in BALF than in plasma. In conclusion, the bronchoalveolar immune response in COVID-19 has a unique local profile that strongly differs from the immune profile in peripheral blood.SummaryThe bronchoalveolar immune response in severe COVID-19 strongly differs from the peripheral blood immune profile. Fatal COVID-19 associated with T cell activation blood, but not in BALF.

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A novel form of immune signaling revealed by transmission of the inflammatory mediator serotonin between dendritic cells and T cells

Blood ◽

10.1182/blood-2005-07-2903 ◽

2006 ◽

Vol 107 (3) ◽

pp. 1010-1017 ◽

Cited By ~ 138

Author(s):

Peta J. O'Connell ◽

Xiangbin Wang ◽

Matilde Leon-Ponte ◽

Corrie Griffiths ◽

Sandeep C. Pingle ◽

...

Keyword(s):

T Cells ◽

Dendritic Cells ◽

T Cell ◽

T Cell Activation ◽

Cell Activation ◽

Activated T Cells ◽

Immune Synapse ◽

Cell Proliferation And Differentiation ◽

Proliferation And Differentiation ◽

5 Ht Uptake

AbstractAdaptive immunity is triggered at the immune synapse, where peptide-major histocompatibility complexes and costimulatory molecules expressed by dendritic cells (DCs) are physically presented to T cells. Here we describe transmission of the inflammatory monoamine serotonin (5-hydroxytryptamine [5-HT]) between these cells. DCs take up 5-HT from the microenvironment and from activated T cells (that synthesize 5-HT) and this uptake is inhibited by the antidepressant, fluoxetine. Expression of 5-HT transporters (SERTs) is regulated by DC maturation, exposure to microbial stimuli, and physical interactions with T cells. Significantly, 5-HT sequestered by DCs is stored within LAMP-1+ vesicles and subsequently released via Ca2+-dependent exocytosis, which was confirmed by amperometric recordings. In turn, extracellular 5-HT can reduce T-cell levels of cAMP, a modulator of T-cell activation. Thus, through the uptake of 5-HT at sites of inflammation, and from activated T cells, DCs may shuttle 5-HT to naive T cells and thereby modulate T-cell proliferation and differentiation. These data constitute the first direct measurement of triggered exocytosis by DCs and reveal a new and rapid type of signaling that may be optimized by the intimate synaptic environment between DCs and T cells. Moreover, these results highlight an important role for 5-HT signaling in immune function and the potential consequences of commonly used drugs that target 5-HT uptake and release.

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T cell-T cell activation in multiple sclerosis

Multiple Sclerosis Journal ◽

10.1177/135245859700300404 ◽

1997 ◽

Vol 3 (4) ◽

pp. 238-242 ◽

Cited By ~ 7

Author(s):

JW Lindsey ◽

RH Kerman ◽

JS Wolinsky

Keyword(s):

Multiple Sclerosis ◽

T Cells ◽

T Cell ◽

T Cell Activation ◽

Cell Activation ◽

Viral Infections ◽

Activated T Cells ◽

In Vitro Proliferation

Activated T cells are able to stimulate proliferation in resting T cells through an antigen non-specific mechanism. The in vivo usefulness of this T cell-T cell activation is unclear, but it may serve to amplify immune responses. T cell-T cell activation could be involved in the well-documented occurrence of multiple sclerosis (MS) exacerbations following viral infections. Excessive activation via this pathway could also be a factor in the etiology of MS. We tested the hypothesis that excessive T cell-T cell activation occurs in MS patients using in vitro proliferation assays comparing T cells from MS patients to T cells from controls. When tested as responder cells, T cells from MS patients proliferated slightly less after stimulation with previously activated cells than T cells from controls. When tested as stimulator cells, activated cells from MS patients stimulated slightly more non-specific proliferation than activated cells from controls. Neither of these differences were statistically significant We conclude that T cell proliferation in response to activated T cells is similar in MS and controls.

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Signaling via LAT (linker for T-cell activation) and Syk/ZAP70 is required for ERK activation and NFAT transcriptional activation following CD2 stimulation

Blood ◽

10.1182/blood.v96.6.2181 ◽

2000 ◽

Vol 96 (6) ◽

pp. 2181-2190 ◽

Cited By ~ 34

Author(s):

Maria Paola Martelli ◽

Huamao Lin ◽

Weiguo Zhang ◽

Lawrence E. Samelson ◽

Barbara E. Bierer

Keyword(s):

T Cells ◽

T Cell ◽

T Cell Activation ◽

Transcriptional Activation ◽

Cell Activation ◽

Interleukin 2 ◽

Cell Receptor ◽

Adapter Protein ◽

Activated T Cells

Abstract Activation of T cells can be initiated through cell surface molecules in addition to the T-cell receptor-CD3 (TCR-CD3) complex. In human T cells, ligation of the CD2 molecule by mitogenic pairs of anti-CD2 monoclonal antibodies activates T cells via biochemical signaling pathways similar but not identical to those elicited on TCR engagement. This study describes a key role for the p36/38 membrane adapter protein linker for T cell activation (LAT) in CD2-mediated T-cell activation. Following ligation of CD2 on the surface of the Jurkat T-cell line and human purified T cells, LAT was tyrosine phosphorylated and shown to associate in vivo with a number of other tyrosine phosphorylated proteins including PLCγ-1, Grb-2, and SLP-76. Using Jurkat cell lines deficient in ZAP70/Syk (P116) or LAT (ANJ3) expression, CD2-dependent PLCγ-1 and SLP-76 tyrosine phosphorylation required expression both of ZAP70 or Syk and of LAT. As predicted, the absence of either LAT or ZAP70/Syk kinases correlated with a defect in the induction of nuclear factor of activated T cells (NFAT) transcriptional activity, activation of the interleukin-2 promoter, and ERK phosphorylation following CD2 stimulation. These data suggest that LAT is an adapter protein important for the regulation of CD2-mediated T-cell activation.

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