Potentiation of CD3-induced expression of the linker for activation of T cells (LAT) by the calcineurin inhibitors cyclosporin A and FK506

Blood ◽  
2000 ◽  
Vol 95 (9) ◽  
pp. 2733-2741 ◽  
Author(s):  
David Peters ◽  
Masahiro Tsuchida ◽  
Eric R. Manthei ◽  
Tausif Alam ◽  
Clifford S. Cho ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cyclosporin A ◽  
T Cell Activation ◽  
Messenger Rna ◽  
Cell Activation ◽  
Calcineurin Inhibitors ◽  
Northern Blotting ◽  
Cellular Level ◽  
Therapeutic Implications

The activation of blood cells, including T cells, triggers intracellular signals that control the expression of critical molecules, including cytokines and cytokine receptors. We show that T-cell receptor (TCR) ligation increases the cellular level of the protein linker for activation of T cells (LAT), a molecule critical for T-cell development and function. T-cell activation increased LAT messenger RNA, as determined by reverse transcription–polymerase chain reaction and by Northern blotting. The TCR-induced increase in LAT expression involved the activation of the serine/threonine kinases PKC and MEK, because inhibitors of these kinases blocked the increase in LAT. Accordingly, the PKC activator phorbol myristate acetate up-regulated LAT expression. Strikingly, the calcineurin inhibitors cyclosporin A (CsA) and FK506 strongly potentiated TCR-induced LAT expression, suggesting that the activation of calcineurin following TCR ligation negatively regulates LAT expression. Accordingly, Ca++ ionophores, which can activate calcineurin by increasing intracellular Ca++, blocked the TCR-induced increase in cellular LAT. CsA and FK506 blocked the Ca++ionophores' inhibitory effect on LAT expression. Notably, CsA and FK506 preferentially up-regulated TCR-induced LAT expression; under the same conditions, these compounds did not increase the expression of 14 other molecules that previously had been implicated in T-cell activation. These data show that TCR-induced LAT expression involves the activation of the PKC-Erk pathway and is negatively regulated by the activation of calcineurin. Furthermore, the potentiation of TCR-induced LAT expression by CsA and FK506 suggests that the action of these agents involves up-regulating the cellular level of critical signaling molecules. These findings may have important therapeutic implications.

Effect of rapamycin on the cyclosporin A–resistant CD28-mediated costimulatory pathway

Blood ◽  
2002 ◽  
Vol 99 (12) ◽  
pp. 4517-4524 ◽  
Author(s):  
Paritosh Ghosh ◽  
Meredith A. Buchholz ◽  
Shingo Yano ◽  
Dennis Taub ◽  
Dan L. Longo
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cyclosporin A ◽  
T Cell Activation ◽  
Messenger Rna ◽  
Cell Activation ◽  
Human Peripheral Blood ◽  
Interleukin 2 ◽  
Immunosuppressive Drug ◽  
Receptor Interaction

The consequences of T-cell activation depend exclusively on costimulation during antigen–T-cell receptor interaction. Interaction between the T-cell coreceptor CD28 and its ligand B7 during antigen-antigen receptor engagement results in full activation of T cells, the outcomes of which are proliferation and effector functions. The ability of CD28 to costimulate the production of interleukin-2 (IL-2) explains the importance of this costimulation. The signaling event mediated by CD28 engagement has been proposed to have 2 components: one is sensitive to the immunosuppressive drug cyclosporin A (CsA), and the other one is CsA-resistant. In this report, we demonstrate that the CsA-resistant pathway is sensitive to the immunosuppressive drug rapamycin. Treatment with rapamycin blocked IL-2 production after activation of human peripheral blood T cells with phorbol ester (PMA) and anti-CD28 (CsA-resistant pathway), whereas this drug did not have any effect on PMA plus ionomycin stimulation (CsA-sensitive pathway). The inhibitory effect of rapamycin was on messenger RNA stability and translation, rather than on IL-2 transcription or protein turnover.

mRNA destabilization by BTG1 and BTG2 maintains T cell quiescence

Science ◽  
2020 ◽  
Vol 367 (6483) ◽  
pp. 1255-1260 ◽  
Author(s):  
Soo Seok Hwang ◽  
Jaechul Lim ◽  
Zhibin Yu ◽  
Philip Kong ◽  
Esen Sefik ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Messenger Rna ◽  
Cell Activation ◽  
Tail Length ◽  
Mrna Abundance ◽  
Quiescent State ◽  
Cell Quiescence ◽  
Global Increase

T cells maintain a quiescent state prior to activation. As inappropriate T cell activation can cause disease, T cell quiescence must be preserved. Despite its importance, the mechanisms underlying the “quiescent state” remain elusive. Here, we identify BTG1 and BTG2 (BTG1/2) as factors responsible for T cell quiescence. BTG1/2-deficient T cells show an increased proliferation and spontaneous activation due to a global increase in messenger RNA (mRNA) abundance, which reduces the threshold to activation. BTG1/2 deficiency leads to an increase in polyadenylate tail length, resulting in a greater mRNA half-life. Thus, BTG1/2 promote the deadenylation and degradation of mRNA to secure T cell quiescence. Our study reveals a key mechanism underlying T cell quiescence and suggests that low mRNA abundance is a crucial feature for maintaining quiescence.

scholarly journals CD28 ligation in T-cell activation: evidence for two signal transduction pathways

Blood ◽  
1990 ◽  
Vol 75 (7) ◽  
pp. 1531-1539 ◽  
Author(s):  
JA Ledbetter ◽  
JB Imboden ◽  
GL Schieven ◽  
LS Grosmaire ◽  
PS Rabinovitch ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Surface ◽  
T Cell Activation ◽  
Messenger Rna ◽  
Protein Tyrosine Kinase ◽  
Cell Activation ◽  
Mrna Stabilization ◽  
Direct Initiation ◽  
Inositol Phospholipid

The CD28 homodimer is thought to function as a signal transducing receptor during activation of T cells. Evidence is presented that the degree of aggregation of CD28 on the cell surface regulates two distinct CD28-associated signals. Binding of bivalent CD28 monoclonal antibody (MoAb) 9.3 upregulates lymphokine production by messenger RNA (mRNA) stabilization, without direct initiation of lymphokine mRNA transcription. This signal was not dependent on inositol phospholipid production or activation of a protein tyrosine kinase (PTK). In contrast, further crosslinking of CD28 on the cell surface rapidly induced formation of large amounts of inositol trisphosphate (InsP3) and increased cytoplasmic calcium concentration [( Ca2+]i), but did not stimulate PTK. CD28 crosslinking directly activated a subset of resting T cells, since CD25 (interleukin [IL]-2 receptor alpha chain) mRNA was rapidly induced in purified T cells, and proliferation, even without addition of exogenous IL-2, was sometimes observed. CD25 expression was detected on the cell surface of approximately 20% of CD4+ T cells. The degree of CD28 aggregation required for activation was investigated by preparing soluble 9.3 x 9.3 conjugates ranging in size from approximately 300 Kd to greater than 1,000 Kd, and comparing their function in T-cell proliferation assays with phorbol-12-myristate-13- acetate (PMA), anti-CD3, or IL-2. There was a correlation between conjugate size and proliferation with IL-2, whereas costimulation with PMA or CD3 was optimized at a lower degree of CD28 aggregation. The inositol phospholipid (InsP) generation and increase in [Ca2+]i after CD28 receptor aggregation appeared to proceed through a pathway different from the CD3/T-cell receptor (TCR) pathway since it was enhanced by pretreatment with PMA, while the InsP and [Ca2+]i signal from crosslinking CD3 was suppressed by PMA. Furthermore, the proliferation response to CD28 aggregation was resistant to inhibition by CD3 modulation. Thus, CD28 aggregation appears to trigger a phospholipase C activation pathway that differs from the CD3/TCR-linked pathway.

scholarly journals Releasing the Brake: Targeting Cbl-b to Enhance Lymphocyte Effector Functions

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Stephanie Wallner ◽  
Thomas Gruber ◽  
Gottfried Baier ◽  
Dominik Wolf
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Malignant Tumors ◽  
Current Knowledge ◽  
Negative Regulator ◽  
Therapeutic Concept ◽  
Therapeutic Implications

The E3 ubiquitin ligase Cbl-b is an established nonredundant negative regulator of T-cell activation. Cbl-b fine-tunes the activation threshold of T cells and uncouples T cells from their vital need of a costimulatory signal to mount a productive immune response. Accordingly, mice deficient incblbare prone to autoimmunity and reject tumors. The latter has been described to be mediatedviaCD8+T cells, which are hyperactive and more abundant in shrinking tumors ofcblb-deficient animals. This might at least also in part be mediated by resistance ofcblb-deficient T cells to negative cues exerted by tumor-associated immuno-suppressive factors, such as TGF-βand regulatory T cells (Treg). Experiments usingcblb-deficient T cells either alone or in combination with vaccines validate the therapeutic concept of enhancing the efficacy of adoptively transferred lymphocytes to treat malignant tumors. This paper summarizes the current knowledge about the negative regulatory role of Cbl-b in T-cell activation and its potential therapeutic implications for cancer immunotherapy.

Transient but Reversible Activation Defect of T-Cell Responses Against Cytomegalovirus and Adenovirus through Immunosuppresion with Calcineurin Inhibitors.

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 4542-4542
Author(s):  
Cornelia Neinhaus ◽  
Kathrin Opherk ◽  
Simone Kayser ◽  
Joseph Leibold ◽  
Judith Feucht ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Response ◽  
Cell Activation ◽  
Immunosuppressive Treatment ◽  
Calcineurin Inhibitors ◽  
T Cell Response ◽  
T Cell Proliferation ◽  
Ciclosporin A

Abstract Abstract 4542 Immunosuppressive treatment is widely used, especially after allogeneic stem cell transplantation (HSCT) to prevent or treat graft versus host disease (GvHD). Common drugs are Ciclosporin A or Tacrolimus in combination with steroids. However, immunosuppressive treatment and the underlying conditions are associated with an increased risk of viral reactivations with persistent pathogens like cytomegalovirus or adenovirus. In the absence of a protective immune response, virus infection remains a life-threatening complication after HSCT. Here we investigated the antiviral T-cell response (n=12) after ex vivo exposition with Ciclosporin A, Tacrolimus, Prednisolone or Mycophenolate at time of immunosuppression, 24 hours and 72 hours later. Analysis has been done with IFNgamma Elispot assays, confirmed by intracellular cytokine staining in flow cytometry and analysis of T-cell proliferation detected by CFSE. The antiviral T-cell response is suppressed after 24 hours using normal serum concentrations (100-200ng/ml) of cyclosporine A. T-cell annergy, induced by cyclosporine, could be reversible, after 72 without immunosuppression. Tacrolimus has a stronger immunosuppressive effect on T-cell activation within the same time and even low levels of 1ng/ml induce T-cell suppression after 72 hours. Peak levels of calcineurin inhibitors even suppressed the T-cell response to superantigens like staphylococcal antigen B or PHA. As expected, Prednisolone had a short and dose dependend effect on T-cell activation. Mycophenolate has a mild effect on the activation of virus-specific T-cells. However, all three drugs induced a significant reduction in Ag-specific T-cell proliferation. In conclusion, Interferonγ detection in virus-specific T-cells is a good diagnostic tool for clinicians to monitor the risk of viral complications in immunosuppressed patients. Tacrolimus, Cyclosporin A, Prednisolone and Mycophenolate induce an activation defect in Ag-specific T-cells with decreasing severity. The effect is reversible and corresponds to high or low serum levels. Disclosures: No relevant conflicts of interest to declare.

scholarly journals The NFAT-1 DNA binding complex in activated T cells contains Fra-1 and JunB.

1993 ◽  
Vol 13 (3) ◽  
pp. 1911-1919 ◽  
Author(s):  
L H Boise ◽  
B Petryniak ◽  
X Mao ◽  
C H June ◽  
C Y Wang ◽  
...  
Keyword(s):  
T Cells ◽  
Transcription Factors ◽  
T Cell ◽  
Cyclosporin A ◽  
Binding Site ◽  
T Cell Activation ◽  
Cell Activation ◽  
Binding Activity ◽  
Activated T Cells ◽  
Quiescent T Cells

Activation of T cells induces transcription of the interleukin-2 (IL-2) gene. IL-2 expression is regulated through the binding of transcription factors to multiple sites within the IL-2 enhancer. One such cis-acting element within the IL-2 enhancer is the NFAT-1 (nuclear factor of activated T cells) binding site. NFAT-1 binding activity is absent in resting cells but is induced upon T-cell activation. The induction of NFAT-1 binding activity can be inhibited by cyclosporin A, potentially accounting for the ability of cyclosporin A to inhibit IL-2 production by T cells. We have previously reported that the NFAT-1 binding complex is composed of at least two proteins and that the 5' portion of the NFAT-1 sequence acts as a binding site for one or more proteins from the Ets family of transcription factors. We now report that the 3' portion of the NFAT-1 sequence contains a variant AP-1 binding site. NFAT-1 binding can be specifically inhibited by oligonucleotides containing a consensus AP-1 site. Moreover, mutation of the AP-1 site at the 3' end of the NFAT-1 sequence inhibits both NFAT-1 binding and the ability of the NFAT-1 binding site to activate expression from a reporter plasmid upon T-cell activation. Since AP-1 sites bind dimeric protein complexes composed of individual members of the Fos and Jun families of transcription factors, we used antibodies specific for individual Fos and Jun family members to determine whether they are present in the NFAT-1 binding complex. These experiments demonstrated that the NFAT-1 binding complex contains JunB and Fra-1 proteins. Northern (RNA) blot analyses demonstrate that both fra-1 and junB mRNAs are induced upon T-cell activation, although fra-1 mRNA is present even in quiescent T cells. Of interest, junB is not expressed in quiescent T cells, and it is induced with kinetics that are similar to those for the induction of IL-2 mRNA expression. Taken together, these results suggested that the JunB-Fra-1 heterodimer is the inducible nuclear component of the NFAT-1 binding activity and that JunB expression regulates the formation of the heterodimer. In addition, these data indicated that specific heterodimers of Fos and Jun family members may have selective roles in the induction of transcription during cellular activation.

scholarly journals CD28 ligation in T-cell activation: evidence for two signal transduction pathways

Blood ◽  
1990 ◽  
Vol 75 (7) ◽  
pp. 1531-1539 ◽  
Author(s):  
JA Ledbetter ◽  
JB Imboden ◽  
GL Schieven ◽  
LS Grosmaire ◽  
PS Rabinovitch ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Surface ◽  
T Cell Activation ◽  
Messenger Rna ◽  
Protein Tyrosine Kinase ◽  
Cell Activation ◽  
Mrna Stabilization ◽  
Direct Initiation ◽  
Inositol Phospholipid

Abstract The CD28 homodimer is thought to function as a signal transducing receptor during activation of T cells. Evidence is presented that the degree of aggregation of CD28 on the cell surface regulates two distinct CD28-associated signals. Binding of bivalent CD28 monoclonal antibody (MoAb) 9.3 upregulates lymphokine production by messenger RNA (mRNA) stabilization, without direct initiation of lymphokine mRNA transcription. This signal was not dependent on inositol phospholipid production or activation of a protein tyrosine kinase (PTK). In contrast, further crosslinking of CD28 on the cell surface rapidly induced formation of large amounts of inositol trisphosphate (InsP3) and increased cytoplasmic calcium concentration [( Ca2+]i), but did not stimulate PTK. CD28 crosslinking directly activated a subset of resting T cells, since CD25 (interleukin [IL]-2 receptor alpha chain) mRNA was rapidly induced in purified T cells, and proliferation, even without addition of exogenous IL-2, was sometimes observed. CD25 expression was detected on the cell surface of approximately 20% of CD4+ T cells. The degree of CD28 aggregation required for activation was investigated by preparing soluble 9.3 x 9.3 conjugates ranging in size from approximately 300 Kd to greater than 1,000 Kd, and comparing their function in T-cell proliferation assays with phorbol-12-myristate-13- acetate (PMA), anti-CD3, or IL-2. There was a correlation between conjugate size and proliferation with IL-2, whereas costimulation with PMA or CD3 was optimized at a lower degree of CD28 aggregation. The inositol phospholipid (InsP) generation and increase in [Ca2+]i after CD28 receptor aggregation appeared to proceed through a pathway different from the CD3/T-cell receptor (TCR) pathway since it was enhanced by pretreatment with PMA, while the InsP and [Ca2+]i signal from crosslinking CD3 was suppressed by PMA. Furthermore, the proliferation response to CD28 aggregation was resistant to inhibition by CD3 modulation. Thus, CD28 aggregation appears to trigger a phospholipase C activation pathway that differs from the CD3/TCR-linked pathway.

The NFAT-1 DNA binding complex in activated T cells contains Fra-1 and JunB

1993 ◽  
Vol 13 (3) ◽  
pp. 1911-1919
Author(s):  
L H Boise ◽  
B Petryniak ◽  
X Mao ◽  
C H June ◽  
C Y Wang ◽  
...  
Keyword(s):  
T Cells ◽  
Transcription Factors ◽  
T Cell ◽  
Cyclosporin A ◽  
Binding Site ◽  
T Cell Activation ◽  
Cell Activation ◽  
Binding Activity ◽  
Activated T Cells ◽  
Quiescent T Cells

Activation of T cells induces transcription of the interleukin-2 (IL-2) gene. IL-2 expression is regulated through the binding of transcription factors to multiple sites within the IL-2 enhancer. One such cis-acting element within the IL-2 enhancer is the NFAT-1 (nuclear factor of activated T cells) binding site. NFAT-1 binding activity is absent in resting cells but is induced upon T-cell activation. The induction of NFAT-1 binding activity can be inhibited by cyclosporin A, potentially accounting for the ability of cyclosporin A to inhibit IL-2 production by T cells. We have previously reported that the NFAT-1 binding complex is composed of at least two proteins and that the 5' portion of the NFAT-1 sequence acts as a binding site for one or more proteins from the Ets family of transcription factors. We now report that the 3' portion of the NFAT-1 sequence contains a variant AP-1 binding site. NFAT-1 binding can be specifically inhibited by oligonucleotides containing a consensus AP-1 site. Moreover, mutation of the AP-1 site at the 3' end of the NFAT-1 sequence inhibits both NFAT-1 binding and the ability of the NFAT-1 binding site to activate expression from a reporter plasmid upon T-cell activation. Since AP-1 sites bind dimeric protein complexes composed of individual members of the Fos and Jun families of transcription factors, we used antibodies specific for individual Fos and Jun family members to determine whether they are present in the NFAT-1 binding complex. These experiments demonstrated that the NFAT-1 binding complex contains JunB and Fra-1 proteins. Northern (RNA) blot analyses demonstrate that both fra-1 and junB mRNAs are induced upon T-cell activation, although fra-1 mRNA is present even in quiescent T cells. Of interest, junB is not expressed in quiescent T cells, and it is induced with kinetics that are similar to those for the induction of IL-2 mRNA expression. Taken together, these results suggested that the JunB-Fra-1 heterodimer is the inducible nuclear component of the NFAT-1 binding activity and that JunB expression regulates the formation of the heterodimer. In addition, these data indicated that specific heterodimers of Fos and Jun family members may have selective roles in the induction of transcription during cellular activation.

scholarly journals Probiotic supplementation reduces inflammatory profiles but does not prevent oral immune perturbations during SIV infection

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Rhianna Jones ◽  
Kyle Kroll ◽  
Courtney Broedlow ◽  
Luca Schifanella ◽  
Scott Smith ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cd4 T Cells ◽  
Cell Activation ◽  
Rhesus Macaques ◽  
Oral Microbiome ◽  
Probiotic Supplementation ◽  
Siv Infection ◽  
Anti Inflammatory

AbstractHIV/SIV infections lead to massive loss of mucosal CD4 + T cells and breakdown of the epithelial mucosa resulting in severe microbial dysbiosis and chronic immune activation that ultimately drive disease progression. Moreover, disruption of one of the most understudied mucosal environments, the oral cavity, during HIV-induced immunosuppression results in significant microbial and neoplastic co-morbidities and contributes to and predicts distal disease complications. In this study we evaluated the effects of oral probiotic supplementation (PBX), which can stimulate and augment inflammatory or anti-inflammatory pathways, on early SIV infection of rhesus macaques. Our study revealed that similar to the GI mucosae, oral CD4 + T cells were rapidly depleted, and as one of the first comprehensive analyses of the oral microflora in SIV infection, we also observed significant modulation among two genera, Porphyromonas and Actinobacillus, early after infection. Interestingly, although PBX therapy did not substantially protect against oral dysbiosis or ameliorate cell loss, it did somewhat dampen inflammation and T cell activation. Collectively, these data provide one of the most comprehensive evaluations of SIV-induced changes in oral microbiome and CD4 + T cell populations, and also suggest that oral PBX may have some anti-inflammatory properties in lentivirus infections.

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