scholarly journals Nanoconfinement of Microvilli Alters Gene Expression and Boosts T cell Activation

2021 ◽  
Author(s):  
Morteza Aramesh ◽  
Diana Stoycheva ◽  
Ioana Sandu ◽  
Stephan J. Ihle ◽  
Tamara Zund ◽  
...  
Keyword(s):  
Gene Expression ◽  
T Cells ◽  
T Cell ◽  
Cell Signaling ◽  
T Cell Activation ◽  
Cell Activation ◽  
Local Environment ◽  
T Cell Signaling ◽  
Sense And Respond ◽  
Altered Gene

T cells sense and respond to their local environment at the nanoscale by forming small actin-rich protrusions, called microvilli, which play critical roles in signaling and antigen recognition, particularly at the interface with the antigen presenting cells. However, the mechanisms by which microvilli contribute to cell signaling and activation is largely unknown. Here, we present a tunable engineered system that promotes microvilli formation and T cell signaling via physical stimuli. We discovered that nanoporous surfaces favored microvilli formation, and markedly altered gene expression in T cells and promoted their activation. Mechanistically, confinement of microvilli inside of nanopores leads to size-dependent sorting of membrane-anchored proteins, specifically segregating CD45 phosphatases and T cell receptors (TCR) from the tip of the protrusions when microvilli are confined in 200 nm pores, but not in 400 nm pores. Consequently, formation of TCR nanoclustered hotspots within 200 nm pores, allows sustained and augmented signaling that prompts T cell activation even in the absence of TCR agonists. The synergistic combination of mechanical and biochemical signals on porous surfaces presents a straightforward strategy to investigate the role of microvilli in T cell signaling as well as to boost T cell activation and expansion for application in the growing field of adoptive immunotherapy.

scholarly journals Nanoconfinement of microvilli alters gene expression and boosts T cell activation

2021 ◽  
Vol 118 (40) ◽  
pp. e2107535118
Author(s):  
Morteza Aramesh ◽  
Diana Stoycheva ◽  
Ioana Sandu ◽  
Stephan J. Ihle ◽  
Tamara Zünd ◽  
...  
Keyword(s):  
Gene Expression ◽  
T Cells ◽  
T Cell ◽  
Cell Signaling ◽  
T Cell Activation ◽  
Cell Activation ◽  
Local Environment ◽  
T Cell Signaling ◽  
Sense And Respond ◽  
Altered Gene

T cells sense and respond to their local environment at the nanoscale by forming small actin-rich protrusions, called microvilli, which play critical roles in signaling and antigen recognition, particularly at the interface with the antigen presenting cells. However, the mechanism by which microvilli contribute to cell signaling and activation is largely unknown. Here, we present a tunable engineered system that promotes microvilli formation and T cell signaling via physical stimuli. We discovered that nanoporous surfaces favored microvilli formation and markedly altered gene expression in T cells and promoted their activation. Mechanistically, confinement of microvilli inside of nanopores leads to size-dependent sorting of membrane-anchored proteins, specifically segregating CD45 phosphatases and T cell receptors (TCR) from the tip of the protrusions when microvilli are confined in 200-nm pores but not in 400-nm pores. Consequently, formation of TCR nanoclustered hotspots within 200-nm pores allows sustained and augmented signaling that prompts T cell activation even in the absence of TCR agonists. The synergistic combination of mechanical and biochemical signals on porous surfaces presents a straightforward strategy to investigate the role of microvilli in T cell signaling as well as to boost T cell activation and expansion for application in the growing field of adoptive immunotherapy.

scholarly journals MAP4K Family Kinases and DUSP Family Phosphatases in T-Cell Signaling and Systemic Lupus Erythematosus

Cells ◽  
2019 ◽  
Vol 8 (11) ◽  
pp. 1433 ◽  
Author(s):  
Chuang ◽  
Tan
Keyword(s):  
Systemic Lupus Erythematosus ◽  
T Cells ◽  
T Cell ◽  
Cell Signaling ◽  
T Cell Activation ◽  
Lupus Erythematosus ◽  
Cell Activation ◽  
Therapeutic Targets ◽  
T Cell Signaling ◽  
Systemic Lupus

T cells play a critical role in the pathogenesis of systemic lupus erythematosus (SLE), which is a severe autoimmune disease. In the past 60 years, only one new therapeutic agent with limited efficacy has been approved for SLE treatment; therefore, the development of early diagnostic biomarkers and therapeutic targets for SLE is desirable. Mitogen-activated protein kinase kinase kinase kinases (MAP4Ks) and dual-specificity phosphatases (DUSPs) are regulators of MAP kinases. Several MAP4Ks and DUSPs are involved in T-cell signaling and autoimmune responses. HPK1 (MAP4K1), DUSP22 (JKAP), and DUSP14 are negative regulators of T-cell activation. Consistently, HPK1 and DUSP22 are downregulated in the T cells of human SLE patients. In contrast, MAP4K3 (GLK) is a positive regulator of T-cell signaling and T-cell-mediated immune responses. MAP4K3 overexpression-induced RORγt–AhR complex specifically controls interleukin 17A (IL-17A) production in T cells, leading to autoimmune responses. Consistently, MAP4K3 and the RORγt–AhR complex are overexpressed in the T cells of human SLE patients, as are DUSP4 and DUSP23. In addition, DUSPs are also involved in either human autoimmune diseases (DUSP2, DUSP7, DUSP10, and DUSP12) or T-cell activation (DUSP1, DUSP5, and DUSP14). In this review, we summarize the MAP4Ks and DUSPs that are potential biomarkers and/or therapeutic targets for SLE.

scholarly journals Disc Large Homolog 1 Is Critical for Early T Cell Receptor Micro Cluster Formation and Activation in Human T Cells

Vaccines ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 1446
Author(s):  
June Guha ◽  
Raj Chari
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Signaling ◽  
T Cell Receptor ◽  
T Cell Activation ◽  
Cell Activation ◽  
Synapse Formation ◽  
Immunological Synapse ◽  
Cell Receptor ◽  
T Cell Signaling

T cell activation by antigen involves multiple sequential steps, including T cell receptor-microcluster TCR-(MC) formation, immunological synapse formation, and phosphorylation of mediators downstream of the TCR. The adaptor protein, Disc Large Homolog 1 (DLG1), is known to regulate proximal TCR signaling and, in turn, T cell activation, acting as a molecular chaperone that organizes specific kinases downstream of antigen recognition. In this study, we used knockdown and knockout technologies in human primary T cells and a human T cell line to demonstrate the role of DLG1 in proximal T cell signaling. High-end confocal microscopy was used for pictorial representation of T cell micro-clusters and colocalization studies. From all these studies, we could demonstrate that DLG1 functions even earlier than immunological synapse formation, to regulate T cell activation by promoting TCR-MC formation. Moreover, we found that DLG1 can act as a bridge between the TCR-ζ chain and ZAP70 while inhibiting binding of the phosphatase SHP1 to TCR-ζ. Together, these effects drive dysregulation of T cell activation in DLG1-deficient T cells. Overall, the activation and survival status of T cell is a critical determinant of effective vaccine response, and DLG1-mediated T cell signaling events can be a driving factor for improving vaccine-designing strategies.

Canonical T cell receptor docking on peptide–MHC is essential for T cell signaling

Science ◽  
2021 ◽  
Vol 372 (6546) ◽  
pp. eabe9124
Author(s):  
Pirooz Zareie ◽  
Christopher Szeto ◽  
Carine Farenc ◽  
Sachith D. Gunasinghe ◽  
Elizabeth M. Kolawole ◽  
...  
Keyword(s):  
T Cell ◽  
Cell Signaling ◽  
T Cell Receptor ◽  
T Cell Activation ◽  
Cell Activation ◽  
Direct Consequence ◽  
Cell Receptor ◽  
T Cell Signaling ◽  
Cell Repertoire

T cell receptor (TCR) recognition of peptide–major histocompatibility complexes (pMHCs) is characterized by a highly conserved docking polarity. Whether this polarity is driven by recognition or signaling constraints remains unclear. Using “reversed-docking” TCRβ-variable (TRBV) 17+ TCRs from the naïve mouse CD8+ T cell repertoire that recognizes the H-2Db–NP366 epitope, we demonstrate that their inability to support T cell activation and in vivo recruitment is a direct consequence of reversed docking polarity and not TCR–pMHCI binding or clustering characteristics. Canonical TCR–pMHCI docking optimally localizes CD8/Lck to the CD3 complex, which is prevented by reversed TCR–pMHCI polarity. The requirement for canonical docking was circumvented by dissociating Lck from CD8. Thus, the consensus TCR–pMHC docking topology is mandated by T cell signaling constraints.

Lysophosphatidic acid enhances interleukin-13 gene expression and promoter activity in T cells

2006 ◽  
Vol 290 (1) ◽  
pp. L66-L74 ◽  
Author(s):  
Joshua Rubenfeld ◽  
Jia Guo ◽  
Nitat Sookrung ◽  
Rongbing Chen ◽  
Wanpen Chaicumpa ◽  
...  
Keyword(s):  
Gene Expression ◽  
T Cells ◽  
T Cell ◽  
Signaling Pathways ◽  
T Cell Activation ◽  
Lysophosphatidic Acid ◽  
Cell Activation ◽  
Human Peripheral Blood ◽  
Regulatory Elements ◽  
Jurkat Cells

Lysophosphatidic acid (LPA) is a membrane-derived lysophospholipid with wide-ranging effects on multiple lung cells including airway epithelial and smooth muscle cells. LPA can augment migration and cytokine synthesis in lymphocytes, but its potential effects on Th2 cytokines have not been well studied. We examined the effects of physiological concentrations of LPA on IL-13 gene expression in human T cells. The Jurkat T cell line and human peripheral blood CD4+ T cells were incubated with LPA alone or with 1) pharmacological agonists of different signaling pathways, or 2) antibodies directed against the T cell receptor complex and costimulatory molecules. Luciferase-based reporter constructs driven by different lengths of the human IL-13 promoter were transfected by electroporation in Jurkat cells treated with and without LPA. The effects of LPA on IL-13 mRNA stability were examined using actinomycin D to halt ongoing transcription. Expression of mRNA encoding LPA2and LPP-1 increased with T cell activation. LPA augmented IL-13 secretion under conditions of submaximal T cell activation. This was observed using pharmacological agonists activating intracellular calcium-, PKC-, and cAMP-dependent signaling pathways, as well as antibodies directed against CD3 and CD28. LPA only slightly prolonged IL-13 mRNA half-life in submaximally stimulated Jurkat cells. In contrast, LPA significantly enhanced transcriptional activation of the IL-13 promoter via regulatory elements contained within proximal 312 bp. The effects of LPA on IL-13 promoter activation appeared to be distinct from those mediated by GATA-3. LPA can augment IL-13 gene expression in T cells, especially under conditions of submaximal activation.

scholarly journals Trapping or slowing the diffusion of T cell receptors at close contacts initiates T cell signaling

2021 ◽  
Vol 118 (39) ◽  
pp. e2024250118 ◽  
Author(s):  
Kevin Y. Chen ◽  
Edward Jenkins ◽  
Markus Körbel ◽  
Aleks Ponjavic ◽  
Anna H. Lippert ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Lipid Bilayers ◽  
T Cell Activation ◽  
Cell Activation ◽  
Cell Receptor ◽  
Stochastic Simulations ◽  
T Cell Signaling ◽  
Extracellular Region ◽  
Close Contacts

T cell activation is initiated by T cell receptor (TCR) phosphorylation. This requires the local depletion of large receptor-type phosphatases from “close contacts” formed when T cells interact with surfaces presenting agonistic TCR ligands, but exactly how the ligands potentiate signaling is unclear. It has been proposed that TCR ligands could enhance receptor phosphorylation and signaling just by holding TCRs in phosphatase-depleted close contacts, but this has not been directly tested. We devised simple methods to move the TCR in and out of close contacts formed by T cells interacting with supported lipid bilayers (SLBs) and to slow the receptor’s diffusion in the contacts, using a series of anti-CD3ε Fab- and ligand-based adducts of the receptor. TCRs engaging a Fab extended with the large extracellular region of CD45 were excluded from contacts and produced no signaling. Conversely, allowing the extended Fab to become tethered to the SLB trapped the TCR in the close contacts, leading to very strong signaling. Importantly, attaching untethered anti-CD3ε Fab or peptide/MHC ligands, each of which were largely inactive in solution but both of which reduced TCR diffusion in close contacts approximately fivefold, also initiated signaling during cell/SLB contact. Our findings indicate that holding TCRs in close contacts or simply slowing their diffusion in phosphatase-depleted regions of the cell surface suffices to initiate signaling, effects we could reproduce in single-particle stochastic simulations. Our study shows that the TCR is preconfigured for signaling in a way that allows it to be triggered by ligands acting simply as receptor “traps.”

DNA mismatch repair deficiency and benefit from adjuvant bevacizumab in NSABP C-08: Molecular profiling results.

2012 ◽  
Vol 30 (30_suppl) ◽  
pp. 55-55
Author(s):  
Katherine L. Pogue-Geile ◽  
Noriko Tanaka ◽  
Patrick Gavin ◽  
Greg Yothers ◽  
Linda H. Colangelo ◽  
...  
Keyword(s):  
Gene Expression ◽  
T Cells ◽  
T Cell ◽  
Mismatch Repair ◽  
T Cell Activation ◽  
Cell Activation ◽  
Statistical Tests ◽  
Differentially Expressed ◽  
Braf Mutations ◽  
Study Gene Expression

55 Background: The purpose of this study was to identify biomarkers that define a subset of patients who received benefit from bevacizumab (bev) in NSABP trial C-08, even though bev did not improve outcomes over standard adjuvant chemotherapy (CT) in the treatment of stage II and III colon cancer. Methods: A randomly selected cohort of C-08 cases (N=500) were profiled for whole genome expression (N=445) and for mutations (N=463) in KRAS, NRAS, PIK3CA, and MET. BRAF mutations and mismatch repair (MMR) status were profiled on the available cases (N=1,764 and 1,993, respectively). Cox proportional hazard models were used to assess prognosis and prediction for the value of bev using overall survival (0S) and time to recurrence (TTR) as end points. Results: The effect of bev was different for MMR deficient (MMR-d) and proficient tumors for OS (interaction p=.035) but not TTR (interaction p=.08). Patients with MMR-d (N=252) tumors showed a significant benefit from the addition of bev to CT for OS (hazard ratio =0.52 (95% CI: 0.29-0.94, p=0.028). KRAS, NRAS, PIK3CA, and MET were not significant for interaction with bev in the discovery cohort. BRAF mutations were associated with MMR status (p<.0001) and the prognostic value of MMR depended on BRAF for TTR (interaction p=.027) but not OS (interaction p=.31). The effect of bev was independent of BRAF (interaction p=.28 TTR and .37 OS). Three-factor interaction tests for bev, MMR, and BRAF were not significant for either endpoint. Gene expression analysis with BRB array tools identified 5 BioCarta pathways (p<0.05) which differentially expressed in 4 statistical tests; 4 of these pathways were directly or indirectly involved in T cell activation and one was involved in the activation of VEGF. Conclusions: Patients in C-08 with MMR-d tumors received benefit from bev treatment but these results need to be validated in a separate study. Gene expression data suggest that T-cells may be differentially expressed based on MMR status. Activation of VEGF has been shown to suppress T-cell development (Ohm et al. Blood. 2003:10;4878). A speculative possibility for the benefit of bev in MMR-d tumors may be due to blocking of VEGF, releasing T cells from VEGF suppression.

scholarly journals T cell signaling and Treg dysfunction correlate to disease kinetics in IL-2Rα-KO autoimmune mice

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Genevieve N. Mullins ◽  
Kristen M. Valentine ◽  
Mufadhal Al-Kuhlani ◽  
Dan Davini ◽  
Kirk D. C. Jensen ◽  
...  
Keyword(s):  
T Cell ◽  
Autoimmune Disease ◽  
Cell Signaling ◽  
T Cell Activation ◽  
Cell Activation ◽  
Bone Marrow Failure ◽  
Systemic Autoimmune Disease ◽  
Cytokine Signaling ◽  
T Cell Signaling ◽  
Immune Parameters

AbstractIL-2Rα, in part, comprises the high affinity receptor for IL-2, a cytokine important in immune proliferation, activation, and regulation. IL-2Rα deficient mice (IL-2Rα-KO) develop systemic autoimmune disease and die from severe anemia between 18 and 80 days of age. These mice develop kinetically distinct autoimmune progression, with approximately a quarter dying by 21 days of age and half dying after 30 days. This research aims to define immune parameters and cytokine signaling that distinguish cohorts of IL-2Rα-KO mice that develop early- versus late-stage autoimmune disease. To investigate these differences, we evaluated complete blood counts (CBC), antibody binding of RBCs, T cell numbers and activation, hematopoietic progenitor changes, and signaling kinetics, during autoimmune hemolytic anemia (AIHA) and bone marrow failure. We identified several alterations that, when combined, correlate to disease kinetics. Early onset disease correlates with anti-RBC antibodies, lower hematocrit, and reduced IL-7 signaling. CD8 regulatory T cells (Tregs) have enhanced apoptosis in early disease. Further, early and late end stage disease, while largely similar, had several differences suggesting distinct mechanisms drive autoimmune disease kinetics. Therefore, IL-2Rα-KO disease pathology rates, driven by T cell signaling, promote effector T cell activation and expansion and Treg dysfunction.

scholarly journals Genetic determinants of chromatin accessibility in T cell activation across humans

2016 ◽  
Author(s):  
Rachel E. Gate ◽  
Christine S. Cheng ◽  
Aviva P. Aiden ◽  
Atsede Siba ◽  
Marcin Tabaka ◽  
...  
Keyword(s):  
Gene Expression ◽  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Genetic Variants ◽  
Cell Activation ◽  
Cell Types ◽  
Regulatory Elements ◽  
Specific Cell ◽  
Accessible Chromatin

AbstractOver 90% of genetic variants associated with complex human traits map to non-coding regions, but little is understood about how they modulate gene regulation in health and disease. One possible mechanism is that genetic variants affect the activity of one or more cis-regulatory elements leading to gene expression variation in specific cell types. To identify such cases, we analyzed Assay for Transposase-Accessible Chromatin sequencing (ATAC-seq) and RNA-seq profiles from activated CD4+ T cells of up to 105 healthy donors. We found that regions of accessible chromatin (ATAC-peaks) are co-accessible at kilobase and megabase resolution, in patterns consistent with the 3D organization of chromosomes measured by in situ Hi-C in T cells. 15% of genetic variants located within ATAC-peaks affected the accessibility of the corresponding peak through disrupting binding sites for transcription factors important for T cell differentiation and activation. These ATAC quantitative trait nucleotides (ATAC-QTNs) have the largest effects on co-accessible peaks, are associated with gene expression from the same aliquot of cells, are rarely affecting core binding motifs, and are enriched for autoimmune disease variants. Our results provide insights into how natural genetic variants modulate cis- regulatory elements, in isolation or in concert, to influence gene expression in primary immune cells that play a key role in many human diseases.

scholarly journals The Tec kinase ITK differentially optimizes NFAT, NF-κB, and MAPK signaling during early T cell activation to regulate graded gene induction

2020 ◽  
Author(s):  
Michael P. Gallagher ◽  
James M. Conley ◽  
Pranitha Vangala ◽  
Andrea Reboldi ◽  
Manuel Garber ◽  
...  
Keyword(s):  
Gene Expression ◽  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Signal Strength ◽  
Mapk Signaling ◽  
Early Gene ◽  
Cell Nuclei ◽  
Activated T Cells

ABSTRACTThe strength of peptide:MHC interactions with the T cell receptor (TCR) is correlated with the time to first cell division, the relative scale of the effector cell response, and the graded expression of activation-associated proteins like IRF4. To regulate T cell activation programming, the TCR and the TCR proximal kinase ITK simultaneously trigger many biochemically separate TCR signaling cascades. T cells lacking ITK exhibit selective impairments in effector T cell responses after activation, but under the strongest signaling conditions ITK activity is dispensable. To gain insight into whether TCR signal strength and ITK activity tune observed graded gene expression through unequal activation of disparate signaling pathways, we examined Erk1/2 activation and NFAT, NF-κB translocation in naive OT-I CD8+ cell nuclei. We observed consistent digital activation of NFAT1 and Erk-MAPK, but NF-κB displayed dynamic, graded activation in response to variation in TCR signal strength and was tunable by treatment with an ITK inhibitor. Inhibitor-treated cells showed dampened induction of AP-1 factors Fos and Fosb, NF-κB response gene transcripts, and survival factor Il2 transcripts. ATAC-seq analysis also revealed genomic regions most sensitive to ITK inhibition were enriched for NF-κB and AP-1 motifs. Specific inhibition of NF-κB during peptide stimulation tuned expression of early gene products like c-Fos. Together, these data indicate a key role for ITK in orchestrating optimal activation of separate TCR downstream pathways, specifically aiding NF-κB activation. More broadly, we revealed a mechanism by which variation in TCR signal strength can produce patterns of graded gene expression in activated T cells.

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