Fbxo7 promotes Cdk6 activity to inhibit PFKP and glycolysis in T cells.

Deregulated Fbxo7 expression is associated with many pathologies, including anaemia, male sterility, cancer, and Parkinson's disease, demonstrating its critical role in a variety of cell types. Although Fbxo7 is an F-box protein that recruits substrates for SCF-type E3 ubiquitin ligases, it also promotes the formation of cyclin D/Cdk6/p27 complexes in an E3-ligase independent fashion. We discovered PFKP, the major gatekeeper of glycolysis, in a screen for Fbxo7 substrates. PFKP has been previously shown to be a critical substrate of Cdk6 for the viability of T-ALL cells. We investigated the molecular relationships between Fbxo7, Cdk6 and PFKP, and the functional effect Fbxo7 has on T cell metabolism, viability, and activation. Fbxo7 promotes Cdk6-independent ubiquitination and Cdk6-dependent phosphorylation of PFKP. Importantly Fbxo7-deficient cells have reduced Cdk6 activity, and haematopoietic and lymphocytic cell lines show a significant dependency on Fbxo7. Compared to WT cells, CD4+ T cells with reduced Fbxo7 expression show increased glycolysis, despite lower cell viability and activation levels. Metabolomic studies of activated CD4+ T cells confirm increased glycolytic flux in Fbxo7-deficient cells, as well as altered nucleotide biosynthesis and arginine metabolism. We show Fbxo7 expression is glucose-responsive at the mRNA and protein level, and we propose Fbxo7 inhibits PFKP and glycolysis via its activation of Cdk6.

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The Impact of Exercise Serum on Selected Parameters of CD4+ T Cell Metabolism

Immuno ◽

10.3390/immuno1030008 ◽

2021 ◽

Vol 1 (3) ◽

pp. 119-131

Author(s):

Jana Palmowski ◽

Kristina Gebhardt ◽

Thomas Reichel ◽

Torsten Frech ◽

Robert Ringseis ◽

...

Keyword(s):

T Cells ◽

Oxygen Consumption ◽

T Cell ◽

Real Time ◽

Cd4 T Cells ◽

Cell Metabolism ◽

Cd4 T Cell ◽

Autologous Serum ◽

Cell Phenotype ◽

The Impact

CD4+ T cells are sensitive to peripheral changes of cytokine levels and metabolic substrates such as glucose and lactate. This study aimed to analyze whether factors released after exercise alter parameters of human T cell metabolism, specifically glycolysis and oxidative phosphorylation. We used primary human CD4+ T cells activated in the presence of autologous serum, which was collected before (CO) and after a 30-min exercise intervention (EX). In the course of activation, cells and supernatants were analyzed for cell viability and diameter, real-time oxygen consumption by using PreSens Technology, mRNA expression of glycolytic enzymes and complexes of the electron transport chain by real-time PCR, glucose, and lactate levels in supernatants, and in vitro differentiation by flow cytometry. EX did not alter T cell phenotype, viability, or on-blast formation. Similarly, no difference between CO and EX were found for CD4+ T cell activation and cellular oxygen consumption. In contrast, higher levels of glucose were found after 48 h activation in EX conditions. T cells activated in autologous exercise serum expressed lower HK1 mRNA and higher IFN-γ receptor 1. We suggest that the exercise protocol used was not sufficient to destabilize the immune metabolism of T cells. Therefore, more intense and prolonged exercise should be used in future studies.

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The Class II Phosphatidylinositol 3 kinase C2β Is Required for the Activation of the K+ Channel KCa3.1 and CD4 T-Cells

Molecular Biology of the Cell ◽

10.1091/mbc.e09-05-0390 ◽

2009 ◽

Vol 20 (17) ◽

pp. 3783-3791 ◽

Cited By ~ 46

Author(s):

Shekhar Srivastava ◽

Lie Di ◽

Olga Zhdanova ◽

Zhai Li ◽

Santosha Vardhana ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

T Cell Activation ◽

Cd4 T Cells ◽

Critical Role ◽

Class Ii ◽

K Channel ◽

Channel Activity ◽

Phosphatidylinositol 3 Kinase ◽

Phosphatidylinositol 3

The Ca2+-activated K+ channel KCa3.1 is required for Ca2+ influx and the subsequent activation of T-cells. We previously showed that nucleoside diphosphate kinase beta (NDPK-B), a mammalian histidine kinase, directly phosphorylates and activates KCa3.1 and is required for the activation of human CD4 T lymphocytes. We now show that the class II phosphatidylinositol 3 kinase C2β (PI3K-C2β) is activated by the T-cell receptor (TCR) and functions upstream of NDPK-B to activate KCa3.1 channel activity. Decreased expression of PI3K-C2β by siRNA in human CD4 T-cells resulted in inhibition of KCa3.1 channel activity. The inhibition was due to decreased phosphatidylinositol 3-phosphate [PI(3)P] because dialyzing PI3K-C2β siRNA-treated T-cells with PI(3)P rescued KCa3.1 channel activity. Moreover, overexpression of PI3K-C2β in KCa3.1-transfected Jurkat T-cells led to increased TCR-stimulated activation of KCa3.1 and Ca2+ influx, whereas silencing of PI3K-C2β inhibited both responses. Using total internal reflection fluorescence microscopy and planar lipid bilayers, we found that PI3K-C2β colocalized with Zap70 and the TCR in peripheral microclusters in the immunological synapse. This is the first demonstration that a class II PI3K plays a critical role in T-cell activation.

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Immune regulation of neuronal injury and repair by observing T cell activation

Proceedings of IMPRS ◽

10.18060/22748 ◽

2018 ◽

Vol 1 (1) ◽

Author(s):

Eric J. Regele ◽

Elizabeth M. Runge ◽

Felicia M. Kennedy ◽

Virginia M. Sanders ◽

Kathryn J. Jones

Keyword(s):

T Cells ◽

T Cell Activation ◽

Cd4 T Cells ◽

Cell Activation ◽

Critical Role ◽

Cd4 Cells ◽

Knock Out ◽

Facial Motoneuron ◽

Injury And Repair ◽

Antigen Presenting

Background and Hypothesis: It is unknown how the immune system maintains the majority of facial motoneuron (FMN) survival after axotomy. IL-10 cytokine is necessary for FMN survival and CD4+ T cells are activated and play a critical role in survival, but do not produce IL-10. It was proposed that the source of IL-10 resides in the CNS; however, it is possible that antigen presenting cells (APC) produce IL-10 which activate CD4+ T cells to a neuroprotective phenotype. The regulation of IL-10 receptors (IL-10R) in immunodeficient compared to wild-type (WT) mice in the facial nucleus was studied in this experiment, as well as the possibility of the PNS producing IL-10. Experimental Design or Project Methods: To study APC’s role in motoneuron survival, we transferred WT whole splenocytes into global IL-10 knock out (KO) mice prior to axotomy. To study IL-10R gene expression, immunodeficient RAG-2 KO mice received WT or IL-10R-/- CD4+ T cells prior to axotomy. Results: qPCR revealed that WT mice upregulate IL-10R after axotomy, whereas RAG-2 KO mice had decreased expression comparatively. RAG-2 mice who received WT CD4+ T cells transfer restored IL-10R comparable to WT values.IL-10R was rescued in RAG-2 mice after the adoptive transfer of WT CD4+T cells. When IL-10R-/- CD4+ cells were transferred into RAG-2 mice, IL-10R values were restored; however, these T cells were unable to rescue FMN survival. Conclusion and Potential Impact: If WT whole splenocytes transferred into global IL-10 KO mice rescue FMN survival, it implies that APC play a role in producing IL-10. If they cannot mediate rescue, then peripheral IL-10 is unlikely sufficient for FMN survival. CD4+ T cells regulate central IL-10R response and must respond to IL-10 to mediate FMN survival. The transfer of whole splenocytes provides APCs capable of producing IL-10 and CD4+ T cells capable of responding to IL-10.

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The critical role of human transcriptional repressor CTCF mRNA up-regulation in the induction of anti-HIV-1 responses in CD4+ T cells

Immunology Letters ◽

10.1016/j.imlet.2007.11.017 ◽

2008 ◽

Vol 117 (1) ◽

pp. 35-44 ◽

Cited By ~ 6

Author(s):

Yuchang Li ◽

Guanhua Li ◽

Anna Ivanova ◽

Sagiv Aaron ◽

Malgorzata Simm

Keyword(s):

T Cells ◽

Cd4 T Cells ◽

Critical Role ◽

Transcriptional Repressor ◽

Anti Hiv ◽

Hiv 1

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Phosphofructokinase deficiency impairs ATP generation, autophagy, and redox balance in rheumatoid arthritis T cells

Journal of Experimental Medicine ◽

10.1084/jem.20130252 ◽

2013 ◽

Vol 210 (10) ◽

pp. 2119-2134 ◽

Cited By ~ 172

Author(s):

Zhen Yang ◽

Hiroshi Fujii ◽

Shalini V. Mohan ◽

Jorg J. Goronzy ◽

Cornelia M. Weyand

Keyword(s):

Rheumatoid Arthritis ◽

T Cells ◽

Cd4 T Cells ◽

Redox Balance ◽

Glycolytic Enzyme ◽

Pentose Phosphate ◽

Glycolytic Flux ◽

Alternative Means ◽

Atp Generation ◽

Phosphofructokinase Deficiency

In the HLA class II–associated autoimmune syndrome rheumatoid arthritis (RA), CD4 T cells are critical drivers of pathogenic immunity. We have explored the metabolic activity of RA T cells and its impact on cellular function and fate. Naive CD4 T cells from RA patients failed to metabolize equal amounts of glucose as age-matched control cells, generated less intracellular ATP, and were apoptosis-susceptible. The defect was attributed to insufficient induction of 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 3 (PFKFB3), a regulatory and rate-limiting glycolytic enzyme known to cause the Warburg effect. Forced overexpression of PFKFB3 in RA T cells restored glycolytic flux and protected cells from excessive apoptosis. Hypoglycolytic RA T cells diverted glucose toward the pentose phosphate pathway, generated more NADPH, and consumed intracellular reactive oxygen species (ROS). PFKFB3 deficiency also constrained the ability of RA T cells to resort to autophagy as an alternative means to provide energy and biosynthetic precursor molecules. PFKFB3 silencing and overexpression identified a novel extraglycolytic role of the enzyme in autophagy regulation. In essence, T cells in RA patients, even those in a naive state, are metabolically reprogrammed with insufficient up-regulation of the glycolytic activator PFKFB3, rendering them energy-deprived, ROS- and autophagy-deficient, apoptosis-sensitive, and prone to undergo senescence.

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Telomerase and CD4 T Cell Immunity in Cancer

Cancers ◽

10.3390/cancers12061687 ◽

2020 ◽

Vol 12 (6) ◽

pp. 1687

Author(s):

Magalie Dosset ◽

Andrea Castro ◽

Hannah Carter ◽

Maurizio Zanetti

Keyword(s):

T Cells ◽

T Cell ◽

Cd4 T Cells ◽

Critical Role ◽

Tumor Formation ◽

T Cell Immunity ◽

Cd4 T Cell ◽

Current Status ◽

Mhc Ii ◽

Cell Immunity

Telomerase reverse transcriptase (TERT) is a conserved self-tumor antigen which is overexpressed in most tumors and plays a critical role in tumor formation and progression. As such, TERT is an antigen of great relevance to develop widely applicable immunotherapies. CD4 T cells play a major role in the anti-cancer response alone or with other effector cells such as CD8 T cells and NK cells. To date, efforts have been made to identify TERT peptides capable of stimulating CD4 T cells that are also able to bind diverse MHC-II alleles to ease immune status monitoring and immunotherapies. Here, we review the current status of TERT biology, TERT/MHC-II immunobiology, and past and current vaccine clinical trials. We propose that monitoring CD4 T cell immunity against TERT is a simple and direct way to assess immune surveillance in cancer patients and a new way to predict the response to immune checkpoint inhibitors (ICPi). Finally, we present the initial results of a systematic discovery of TERT peptides able to bind the most common HLA Class II alleles worldwide and show that the repertoire of MHC-II TERT peptides is wider than currently appreciated.

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The critical role of CD4+ T cells in PD-1 blockade against MHC-II–expressing tumors such as classic Hodgkin lymphoma

Blood Advances ◽

10.1182/bloodadvances.2020002098 ◽

2020 ◽

Vol 4 (17) ◽

pp. 4069-4082

Author(s):

Joji Nagasaki ◽

Yosuke Togashi ◽

Takeaki Sugawara ◽

Makiko Itami ◽

Nobuhiko Yamauchi ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Cd4 T Cells ◽

Critical Role ◽

Cd4 T Cell ◽

Antitumor Effects ◽

Cell Axis ◽

Mhc I ◽

Mhc Ii

Abstract Classic Hodgkin lymphoma (cHL) responds markedly to PD-1 blockade therapy, and the clinical responses are reportedly dependent on expression of major histocompatibility complex class II (MHC-II). This dependence is different from other solid tumors, in which the MHC class I (MHC-I)/CD8+ T-cell axis plays a critical role. In this study, we investigated the role of the MHC-II/CD4+ T-cell axis in the antitumor effect of PD-1 blockade on cHL. In cHL, MHC-I expression was frequently lost, but MHC-II expression was maintained. CD4+ T cells highly infiltrated the tumor microenvironment of MHC-II–expressing cHL, regardless of MHC-I expression status. Consequently, CD4+ T-cell, but not CD8+ T-cell, infiltration was a good prognostic factor in cHL, and PD-1 blockade showed antitumor efficacy against MHC-II–expressing cHL associated with CD4+ T-cell infiltration. Murine lymphoma and solid tumor models revealed the critical role of antitumor effects mediated by CD4+ T cells: an anti-PD-1 monoclonal antibody exerted antitumor effects on MHC-I−MHC-II+ tumors but not on MHC-I−MHC-II− tumors, in a cytotoxic CD4+ T-cell–dependent manner. Furthermore, LAG-3, which reportedly binds to MHC-II, was highly expressed by tumor-infiltrating CD4+ T cells in MHC-II–expressing tumors. Therefore, the combination of LAG-3 blockade with PD-1 blockade showed a far stronger antitumor immunity compared with either treatment alone. We propose that PD-1 blockade therapies have antitumor effects on MHC-II–expressing tumors such as cHL that are mediated by cytotoxic CD4+ T cells and that LAG-3 could be a candidate for combination therapy with PD-1 blockade.

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