scholarly journals Titanium Ions Promote Exogenous Calcium-Dependent Calcium Influx in Activated Jurkat T Cells: A Possible Mechanism to Explain Its Immunostimulatory Properties

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Jing Chen ◽  
Qiuying Li ◽  
Zhenhua Pang ◽  
Ming Gong ◽  
Li Tang
Keyword(s):  
T Cells ◽  
T Cell ◽  
Intracellular Calcium ◽  
T Cell Activation ◽  
Calcium Influx ◽  
Biological Activities ◽  
Jurkat Cells ◽  
Dependent Manner ◽  
Jurkat T Cells ◽  
Exogenous Calcium

Titanium and its alloys have been widely used in dental and orthopedic implants. Owing to the biotribocorrosion behavior of implants in simulated oral environment, Ti(IV) ions could be released into surrounding tissues. Current studies have found that Ti(IV) ions could affect the biological activities of immune cells in adjacent tissues and subsequently jeopardize the long-term performance of implant prostheses. However, the potential mechanism underlying its immunomodulatory properties remains unclear. Calcium signaling has been confirmed to be involved in regulation of lymphocyte immune function. Therefore, we hypothesize that Ti(IV) ions modulated T cell function through the change of intracellular calcium concentrations. This study is aimed at exploring the role of intracellular calcium responses in the modulatory effect of Ti(IV) ions on unactivated and phytohemagglutinin-activated Jurkat T cells. Here, we confirmed that Ti(IV) ions within a certain concentration range induced CD69 expression on both unactivated and activated T cells in our study. Additionally, the combined stimulation with Ti(IV) ions and PHA increased expression of IL-1β, TNF-α, and RANKL. Furthermore, we found that treatment with Ti(IV) induced a transitory increase in the levels of [Ca2+]i in activated Jurkat cells, dependent on the presence of exogenous calcium. Treatment with different doses of Ti(IV) for 24 h significantly increased the levels of [Ca2+]i in the activated Jurkat cells in a dose-dependent manner, but had little effect in the unactivated cells. Treatment with Ti(IV) did not significantly affect the PLCγ1 activation and inositol-1,4,5-trisphosphate (IP3) secretion in Jurkat cells. Taken together, these data indicated that Ti(IV) enhanced calcium influx during the T cell activation, independent of IP3-mediated intracellular calcium release. Our work provides insights into the mechanism involved in the regulation of lymphocyte behaviors under the effect of Ti(IV) ions, which may help to develop therapeutic strategies for dental implant failures.

RIAM Regulates Actin Reorganization at the Immunological Synapse and Calcium Mobilization during T Cell Activation.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 1722-1722
Author(s):  
Esther M. Lafuente ◽  
Mathew Salanga ◽  
Yoshiko Iwamoto ◽  
Lequn Li ◽  
Vassiliki A. Boussiotis
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
T Cell Activation ◽  
Cell Activation ◽  
Immunological Synapse ◽  
Jurkat Cells ◽  
Jurkat T Cells ◽  
Actin Reorganization ◽  
Cytoskeletal Dynamics

Abstract Engagement of immune recognition subunits on lymphocytes results in cytoskeletal reorganization, polarization of polymerized actin, conjugate formation between T cells and APC, stabilization of the immunological synapse (IS), and initiation of signaling cascades leading to T cell activation. Actin remodeling is essential for these events and is mandatory for T cell activation. We have identified RIAM, a novel adaptor molecule that interacts specifically with active GTP-bound Rap1 and with regulators of the actin cytoskeleton Evl, VASP and Profilin. Profilin associates with G-actin and promotes actin polymerization by adding actin monomers to the barbed ends of F-actin. Ena/VASP family proteins are cytoskeletal proteins and regulate actin dynamics. Via these interactions, RIAM functions as a regulator of the actin cytoskeleton. RIAM also has a mandatory role in regulating activation of integrins downstream of Rap1. The ability of a T cell to recognize and conjugate with an APC is dependent on cytoskeletal dynamics and “inside out” signaling leading to integrin-mediated adhesion. Activation of the b2 integrin LFA-1 leads to high avidity binding to ICAM proteins, which is crucial for stable T cell-APC conjugation. Because RIAM is involved both in cytoskeletal dynamics and integrin activation, we examined whether RIAM had a role in this process. Stable GFP-transfected Jurkat T cells were incubated with Raji B cells as APC, in the presence or absence of SEE. T cell:APC conjugates and formation of IS were examined by confocal microscopy. Synapse formation between GFP-Jurkat cells and Raji B cells was detected only in the presence of SEE. Under these conditions, polymerized (F) actin was highly recruited at the IS, as determined by phalloidin staining. Staining with RIAM-specific antibody indicated that in the absence of antigen, RIAM was diffusely expressed in the cytoplasm and at the plasma membrane. Impressively, upon incubation with SEE loaded Raji cells, RIAM was redistributed at the IS where it co-localized with polymerized (F) actin and ZAP-70. Knockdown of RIAM in Jurkat T cells resulted in significant defects in conjugate formation with SEE loaded B cells. Thus RIAM is involved in actin reorganization in the IS and in the formation of T cell:APC conjugates. Because appropriate actin reorganization is required for T cell activation we next explored whether RIAM knockdown leads to defects in TCR-mediated signaling events. RIAM-knockdown Jurkat T cells displayed significantly impaired IL-2 production in response to SEE loaded Raji and in decreased IL-2 promoter driven transcriptional activity. Surprisingly, despite the significant decrease in IL-2 transcription, RIAM-knockdown Jurkat cells did not show altered TCR-induced phosphorylation of PLCg1, or activation of MAP kinases including MEK, Erk1/2 and JNK, compared to control cells. Moreover, AP-1 and NF-kB-mediated gene transcription induced by CD3-plus-CD28 was unaffected. In contrast, NFAT-driven transcription was significantly impaired. Assessment of intracellular calcium by flow cytometry indicated that RIAM-knockdown cells had significantly reduced TCR-mediated intracellular calcium signal. These results indicate that RIAM is an important component of a signaling pathway that regulates calcium mobilization and NFAT mediated gene transcription in T lymphocytes.

scholarly journals SEA Antagonizes the Imatinib-Meditated Inhibitory Effects on T Cell Activation via the TCR Signaling Pathway

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Guanming Wang ◽  
Yuhui Yan ◽  
Xiaohua Chen ◽  
Chen Lin ◽  
Yangqiu Li
Keyword(s):  
T Cells ◽  
T Cell ◽  
Signaling Pathway ◽  
T Cell Activation ◽  
Cell Activation ◽  
Jurkat Cells ◽  
Imatinib Treatment ◽  
Dependent Manner ◽  
Inhibitory Effects ◽  
Tcr Signaling

The BCR-ABL kinase inhibitor imatinib is highly effective in the treatment of chronic myeloid leukemia (CML). However, long-term imatinib treatment induces immunosuppression, which is mainly due to T cell dysfunction. Imatinib can reduce TCR-triggered T cell activation by inhibiting the phosphorylation of tyrosine kinases such as Lck, ZAP70, LAT, and PLCγ1 early in the TCR signaling pathway. The purpose of this study was to investigate whether the superantigen SEA, a potent T cell stimulator, can block the immunosuppressive effects of imatinib on T cells. Our data show that the exposure of primary human T cells and Jurkat cells to SEA for 24 h leads to the upregulation of the Lck and ZAP70 proteins in a dose-dependent manner. T cells treated with SEA prior to TCR binding had increased the tyrosine phosphorylation of Lck, ZAP70, and PLCγ1. Pretreatment with SEA prevents the inhibitory effects of imatinib on TCR signaling, which leads to T cell proliferation and IL-2 production. It is conceivable that SEA antagonizes the imatinib-mediated inhibition of T cell activation and proliferation through the TCR signaling pathway.

scholarly journals Hypoxia-induced PD-L1/PD-1 crosstalk impairs T-cell function in sleep apnoea

2017 ◽  
Vol 50 (4) ◽  
pp. 1700833 ◽  
Author(s):  
Carolina Cubillos-Zapata ◽  
Jose Avendaño-Ortiz ◽  
Enrique Hernandez-Jimenez ◽  
Victor Toledano ◽  
Jose Casas-Martin ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Intermittent Hypoxia ◽  
Cell Activation ◽  
Cell Function ◽  
Sleep Apnoea ◽  
Orphan Receptor ◽  
Dependent Manner ◽  
Obstructive Sleep

Obstructive sleep apnoea (OSA) is associated with higher cancer incidence, tumour aggressiveness and cancer mortality, as well as greater severity of infections, which have been attributed to an immune deregulation. We studied the expression of programmed cell death (PD)-1 receptor and its ligand (PD-L1) on immune cells from patients with OSA, and its consequences on immune-suppressing activity. We report that PD-L1 was overexpressed on monocytes and PD-1 was overexpressed on CD8+ T-cells in a severity-dependent manner. PD-L1 and PD-1 overexpression were induced in both the human in vitro and murine models of intermittent hypoxia, as well as by hypoxia-inducible factor-1α transfection. PD-L1/PD-1 crosstalk suppressed T-cell proliferation and activation of autologous T-lymphocytes and impaired the cytotoxic activity of CD8+ T-cells. In addition, monocytes from patients with OSA exhibited high levels of retinoic acid related orphan receptor, which might explain the differentiation of myeloid-derived suppressor cells. Intermittent hypoxia upregulated the PD-L1/PD-1 crosstalk in patients with OSA, resulting in a reduction in CD8+ T-cell activation and cytotoxicity, providing biological plausibility to the increased incidence and aggressiveness of cancer and the higher risk of infections described in these patients.

scholarly journals Modulating p56Lck in T-Cells by a Chimeric Peptide Comprising Two Functionally Different Motifs of Tip fromHerpesvirus saimiri

2015 ◽  
Vol 2015 ◽  
pp. 1-12
Author(s):  
Jean-Paul Vernot ◽  
Ana María Perdomo-Arciniegas ◽  
Luis Alberto Pérez-Quintero ◽  
Diego Fernando Martínez
Keyword(s):  
T Cells ◽  
T Cell ◽  
Lipid Rafts ◽  
T Cell Activation ◽  
Cell Activation ◽  
Jurkat Cells ◽  
Chimeric Peptide ◽  
Vector Targeting

The Lck interacting protein Tip ofHerpesvirus saimiriis responsible for T-cell transformation bothin vitroandin vivo. Here we designed the chimeric peptide hTip-CSKH, comprising the Lck specific interacting motif CSKH of Tip and its hydrophobic transmembrane sequence (hTip), the latter as a vector targeting lipid rafts. We found that hTip-CSKH can induce a fivefold increase in proliferation of human andAotussp. T-cells. Costimulation with PMA did not enhance this proliferation rate, suggesting that hTip-CSKH is sufficient and independent of further PKC stimulation. We also found that human Lck phosphorylation was increased earlier after stimulation when T-cells were incubated previously with hTip-CSKH, supporting a strong signalling and proliferative effect of the chimeric peptide. Additionally, Lck downstream signalling was evident with hTip-CSKH but not with control peptides. Importantly, hTip-CSKH could be identified in heavy lipid rafts membrane fractions, a compartment where important T-cell signalling molecules (LAT, Ras, and Lck) are present during T-cell activation. Interestingly, hTip-CSKH was inhibitory to Jurkat cells, in total agreement with the different signalling pathways and activation requirements of this leukemic cell line. These results provide the basis for the development of new compounds capable of modulating therapeutic targets present in lipid rafts.

scholarly journals Human T cell activation. IV. T cell activation and proliferation via the early activation antigen EA 1.

1989 ◽  
Vol 169 (3) ◽  
pp. 677-689 ◽  
Author(s):  
S Nakamura ◽  
S S Sung ◽  
J M Bjorndahl ◽  
S M Fu
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Mrna Levels ◽  
Dependent Manner ◽  
Early Activation ◽  
Human T Cell ◽  
Accessory Cells ◽  
Activation Antigen

A new mAb G38 was generated against purified EA 1, an early activation antigen. In immunoprecipitation, it was reactive with the same complex precipitated by the initial anti-EA 1 mAb P8. mAb G38 augmented PMA-induced proliferation of PBMC. It was shown to be mitogenic for purified T cells in collaboration with PMA in a dose-dependent manner. This effect was independent of monocytes and other accessory cells. mAb G38 augmented PMA-induced IL-2-R expression. In conjunction with PMA, it induced IL-2 synthesis and secretion. Its effects on IL-2-R and IL-2 expression were documented at both protein and mRNA levels. Both anti-EA 1 mAbs did not induce Ca2+ influx by themselves in PMA-treated T cells. However, the addition of second anti-mouse Ig antibodies induced readily detectable increases in [Ca2+]i. Ca2+-mediated pathways may be utilized as the transduction signal mechanisms. mAb Leu-23 was shown to be reactive with EA 1. mAb Leu-23 was also mitogenic for T cells in the presence of PMA. These findings provide evidence for a functional role for EA 1 in T cell activation and proliferation.

scholarly journals Tyrosine 192 within the SH2 domain of the Src-protein tyrosine kinase p56Lck regulates T-cell activation independently of Lck/CD45 interactions

2020 ◽  
Vol 18 (1) ◽  
Author(s):  
Matthias Kästle ◽  
Camilla Merten ◽  
Roland Hartig ◽  
Thilo Kaehne ◽  
Ardiyanto Liaunardy-Jopeace ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Tyrosine Kinase ◽  
Enzymatic Activity ◽  
T Cell Activation ◽  
Protein Tyrosine Kinase ◽  
Cell Activation ◽  
Sh2 Domain ◽  
Jurkat T Cells

Abstract Background Upon engagement of the T-cell receptor (TCR), the Src-family protein tyrosine kinase p56Lck phosphorylates components of the TCR (e.g. the TCRζ chains), thereby initiating T-cell activation. The enzymatic activity of Lck is primarily regulated via reversible and dynamic phosphorylation of two tyrosine residues, Y394 and Y505. Lck possesses an additional highly conserved tyrosine Y192, located within the SH2 domain, whose role in T-cell activation is not fully understood. Methods Knock-in mice expressing a phospho-mimetic (Y192E) form of Lck were generated. Cellular and biochemical characterization was performed to elucidate the function of Y192 in primary T cells. HEK 293T and Jurkat T cells were used for in vitro studies. Results Co-immunoprecipitation studies and biochemical analyses using T cells from LckY192E knock-in mice revealed a diminished binding of LckY192E to CD45 and a concomitant hyperphosphorylation of Y505, thus corroborating previous data obtained in Jurkat T cells. Surprisingly however, in vitro kinase assays showed that LckY192E possesses a normal enzymatic activity in human and murine T cells. FLIM/FRET measurements employing an LckY192E biosensor further indicated that the steady state conformation of the LckY192E mutant is similar to Lckwt. These data suggest that Y192 might regulate Lck functions also independently from the Lck/CD45-association. Indeed, when LckY192E was expressed in CD45−/−/Csk−/− non-T cells (HEK 293T cells), phosphorylation of Y505 was similar to Lckwt, but LckY192E still failed to optimally phosphorylate and activate the Lck downstream substrate ZAP70. Furthermore, LckY19E was recruited less to CD3 after TCR stimulation. Conclusions Taken together, phosphorylation of Y192 regulates Lck functions in T cells at least twofold, by preventing Lck association to CD45 and by modulating ligand-induced recruitment of Lck to the TCR. Major findings Our data change the current view on the function of Y192 and suggest that Y192 also regulates Lck activity in a manner independent of Y505 phosphorylation.

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 NSOM/QD-Based Visualization of GM1 Serving as Platforms for TCR/CD3 Mediated T-Cell Activation

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Liyun Zhong ◽  
Zhun Zhang ◽  
Xiaoxu Lu ◽  
Shengde Liu ◽  
Crystal Y. Chen ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Imaging System ◽  
Near Field ◽  
Cell Receptor ◽  
Dependent Manner ◽  
Receptor Complexes ◽  
Before And After

Direct molecular imaging of nanoscale relationship between T-cell receptor complexes (TCR/CD3) and gangliosidosis GM1 before and after T-cell activation has not been reported. In this study, we made use of our expertise of near-field scanning optical microscopy(NSOM)/immune-labeling quantum dots- (QD-)based dual-color imaging system to visualize nanoscale profiles for distribution and organization of TCR/CD3, GM1, as well as their nanospatial relationship and their correlation with PKCθsignaling cascade during T-cell activation. Interestingly, after anti-CD3/anti-CD28 Ab co-stimulation, both TCR/CD3 and GM1 were clustered to form nanodomains; moreover, all of TCR/CD3 nanodomains were colocalized with GM1 nanodomains, indicating that the formation of GM1 nanodomains was greatly correlated with TCR/CD3 mediated signaling. Specially, while T-cells were pretreated with PKCθsignaling inhibitor rottlerin to suppress IL-2 cytokine production, no visible TCR/CD3 nanodomains appeared while a lot of GM1 nanodomains were still observed. However, while T-cells are pretreated with PKCαβsignaling inhibitor GÖ6976 to suppress calcium-dependent manner, all of TCR/CD3 nanodomains were still colocalized with GM1 nanodomains. These findings possibly support the notion that the formation of GM1 nanodomains indeed serves as platforms for the recruitment of TCR/CD3 nanodomains, and TCR/CD3 nanodomains are required for PKCθsignaling cascades and T-cell activation

scholarly journals Epigenetic regulation of Kcna3-encoding Kv1.3 potassium channel by cereblon contributes to regulation of CD4+ T-cell activation

2016 ◽  
Vol 113 (31) ◽  
pp. 8771-8776 ◽  
Author(s):  
Jung-Ah Kang ◽  
Sang-Heon Park ◽  
Sang Phil Jeong ◽  
Min-Hee Han ◽  
Cho-Rong Lee ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Potassium Channel ◽  
T Cell Activation ◽  
Epigenetic Regulation ◽  
Cell Activation ◽  
Calcium Influx ◽  
Epigenetic Modification ◽  
Binding Motif ◽  
Potassium Flux

The role of cereblon (CRBN) in T cells is not well understood. We generated mice with a deletion in Crbn and found cereblon to be an important antagonist of T-cell activation. In mice lacking CRBN, CD4+ T cells show increased activation and IL-2 production on T-cell receptor stimulation, ultimately resulting in increased potassium flux and calcium-mediated signaling. CRBN restricts T-cell activation via epigenetic modification of Kcna3, which encodes the Kv1.3 potassium channel required for robust calcium influx in T cells. CRBN binds directly to conserved DNA elements adjacent to Kcna3 via a previously uncharacterized DNA-binding motif. Consequently, in the absence of CRBN, the expression of Kv1.3 is derepressed, resulting in increased Kv1.3 expression, potassium flux, and CD4+ T-cell hyperactivation. In addition, experimental autoimmune encephalomyelitis in T-cell–specific Crbn-deficient mice was exacerbated by increased T-cell activation via Kv1.3. Thus, CRBN limits CD4+ T-cell activation via epigenetic regulation of Kv1.3 expression.

18β-Glycyrrhetinic acid potently inhibits Kv1.3 potassium channels and T cell activation in human Jurkat T cells

2013 ◽  
Vol 148 (2) ◽  
pp. 647-654 ◽  
Author(s):  
Xiao-Xing Fu ◽  
Li-Li Du ◽  
Ning Zhao ◽  
Qian Dong ◽  
Yu-Hua Liao ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Potassium Channels ◽  
T Cell Activation ◽  
Cell Activation ◽  
Glycyrrhetinic Acid ◽  
Jurkat T Cells
Sign in / Sign up

Export Citation Format

Share Document