scholarly journals The Gtpase Rho Controls a P53-Dependent Survival Checkpoint during Thymopoiesis

2000 ◽  
Vol 192 (1) ◽  
pp. 77-86 ◽  
Author(s):  
Patrick S. Costello ◽  
Steve C. Cleverley ◽  
Ricciarda Galandrini ◽  
Stefan W. Henning ◽  
Doreen A. Cantrell
Keyword(s):  
T Cells ◽  
Cell Death ◽  
T Cell ◽  
Cell Survival ◽  
Ectopic Expression ◽  
Double Positive ◽  
Cell Stage ◽  
Guanine Nucleotide Binding Protein ◽  
Survival Signaling ◽  
T Cell Progenitors

During the early stages of thymopoiesis, cell survival is controlled by cytokines that regulate the expression of antiapoptotic proteins such as Bcl-2. At the pre-T cell stage, a critical checkpoint for β chain selection is monitored by the tumor suppressor p53: pre-T cells can survive and differentiate when p53 is removed genetically or when its proapoptotic function is inactivated physiologically as a consequence of signaling through the pre-T cell receptor complex. Previous work has shown that the guanine nucleotide binding protein Rho controls cell survival in T cell progenitors. Here we define the survival pathways controlled by Rho in pre-T cells and show that this GTPase is a pivotal regulator of the p53-mediated checkpoint operating at the time of β selection: loss of Rho function results in apoptosis in pre-T cells, but this cell death is prevented by loss of p53. The prevention of cell death by loss of p53 restored numbers of early T cell progenitors but did not fully restore thymic cellularity. Further analysis revealed that loss of Rho function caused survival defects in CD4/8 double-positive thymocytes that is independent of p53 but can be prevented by ectopic expression of Bcl-2. These studies highlight that the GTPase Rho is a crucial component of survival signaling pathways in at least two different thymocyte subpopulations: Rho controls the p53 survival checkpoint in pre-T cells and is also crucial for a p53 independent survival signaling pathway in CD4/8 double positives.

scholarly journals A Novel Gene Essential for the Development of Single Positive Thymocytes

2009 ◽  
Vol 29 (18) ◽  
pp. 5128-5135 ◽  
Author(s):  
Kiyokazu Kakugawa ◽  
Takuwa Yasuda ◽  
Ikuo Miura ◽  
Ayako Kobayashi ◽  
Hitomi Fukiage ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Mutant Mice ◽  
Cell Phenotype ◽  
Double Positive ◽  
Cell Stage ◽  
Class I Mhc ◽  
Orphan Gene ◽  
Novel Gene ◽  
Single Positive

ABSTRACT A critical step during intrathymic T-cell development is the transition of CD4+ CD8+ double-positive (DP) cells to the major histocompatibility complex class I (MHC-I)-restricted CD4− CD8+ and MHC-II-restricted CD4+ CD8− single-positive (SP) cell stage. Here, we identify a novel gene that is essential for this process. Through the T-cell phenotype-based screening of N-ethyl-N-nitrosourea (ENU)-induced mutant mice, we established a mouse line in which numbers of CD4 and CD8 SP thymocytes as well as peripheral CD4 and CD8 T cells were dramatically reduced. Using linkage analysis and DNA sequencing, we identified a missense point mutation in a gene, E430004N04Rik (also known as themis), that does not belong to any known gene family. This orphan gene is expressed specifically in DP and SP thymocytes and peripheral T cells, whereas in mutant thymocytes the levels of protein encoded by this gene were drastically reduced. We generated E430004N04Rik-deficient mice, and their phenotype was virtually identical to that of the ENU mutant mice, thereby confirming that this gene is essential for the development of SP thymocytes.

scholarly journals Protein phosphatase 2A has an essential role in promoting thymocyte survival during selection

2019 ◽  
Vol 116 (25) ◽  
pp. 12422-12427 ◽  
Author(s):  
Mingzhu Zheng ◽  
Dan Li ◽  
Zhishan Zhao ◽  
Dmytro Shytikov ◽  
Qin Xu ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Positive Selection ◽  
Cell Survival ◽  
Protein Phosphatase ◽  
Essential Role ◽  
Protein Phosphatase 2A ◽  
Thymocyte Development ◽  
Double Positive ◽  
Phosphatase 2A

The development of thymocytes to mature T cells in the thymus is tightly controlled by cellular selection, in which only a small fraction of thymocytes equipped with proper quality of TCRs progress to maturation. It is pivotal to protect the survival of the few T cells, which pass the selection. However, the signaling events, which safeguard the cell survival in thymus, are not totally understood. In this study, protein Ser/Thr phosphorylation in thymocytes undergoing positive selection is profiled by mass spectrometry. The results revealed large numbers of dephosphorylation changes upon T cell receptor (TCR) activation during positive selection. Subsequent substrate analysis pinpointed protein phosphatase 2A (PP2A) as the enzyme responsible for the dephosphorylation changes in developing thymocytes. PP2A catalytic subunit α (Ppp2ca) deletion in the T cell lineage in Ppp2caflox/flox-Lck-Cre mice (PP2A cKO) displayed dysregulated dephosphorylation of apoptosis-related proteins in double-positive (DP) cells and caused substantially decreased numbers of DP CD4+ CD8+ cells. Increased levels of apoptosis in PP2A cKO DP cells were found to underlie aberrant thymocyte development. Finally, the defective thymocyte development in PP2A cKO mice could be rescued by either Bcl2 transgene expression or by p53 knockout. In summary, our work reveals an essential role of PP2A in promoting thymocyte development through the regulation of cell survival.

scholarly journals NLRP6 Deficiency in CD4 T Cells Decreases T Cell Survival Associated with Increased Cell Death

2019 ◽  
Vol 203 (2) ◽  
pp. 544-556 ◽  
Author(s):  
Katarina Radulovic ◽  
C. Korcan Ayata ◽  
Rachel Mak'Anyengo ◽  
Kristina Lechner ◽  
Philipp Wuggenig ◽  
...  
Keyword(s):  
T Cells ◽  
Cell Death ◽  
T Cell ◽  
Cell Survival ◽  
Cd4 T Cells ◽  
T Cell Survival

scholarly journals Thymocyte Maturation Is Regulated by the Activity of the Helix-Loop-Helix Protein, E47

1999 ◽  
Vol 190 (11) ◽  
pp. 1605-1616 ◽  
Author(s):  
Gretchen Bain ◽  
Melanie W. Quong ◽  
Rachel S. Soloff ◽  
Stephen M. Hedrick ◽  
Cornelis Murre
Keyword(s):  
T Cells ◽  
T Cell ◽  
Positive Selection ◽  
Mhc Class I ◽  
Ectopic Expression ◽  
Class I ◽  
Double Positive ◽  
Helix Loop Helix

The E2A proteins, E12 and E47, are required for progression through multiple developmental pathways, including early B and T lymphopoiesis. Here, we provide in vitro and in vivo evidence demonstrating that E47 activity regulates double-positive thymocyte maturation. In the absence of E47 activity, positive selection of both major histocompatibility complex (MHC) class I– and class II–restricted T cell receptors (TCRs) is perturbed. Additionally, development of CD8 lineage T cells in an MHC class I–restricted TCR transgenic background is sensitive to the dosage of E47. Mice deficient for E47 display an increase in production of mature CD4 and CD8 lineage T cells. Furthermore, ectopic expression of an E2A inhibitor helix-loop-helix protein, Id3, promotes the in vitro differentiation of an immature T cell line. These results demonstrate that E2A functions as a regulator of thymocyte positive selection.

scholarly journals Immunogenomic Gene Signature of Cell-Death Associated Genes with Prognostic Implications in Lung Cancer

Cancers ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 155
Author(s):  
Pankaj Ahluwalia ◽  
Meenakshi Ahluwalia ◽  
Ashis K. Mondal ◽  
Nikhil Sahajpal ◽  
Vamsi Kota ◽  
...  
Keyword(s):  
Lung Cancer ◽  
T Cells ◽  
Cell Death ◽  
T Cell ◽  
High Risk ◽  
Lung Adenocarcinoma ◽  
Risk Group ◽  
High Risk Group ◽  
Free Survival ◽  
Cell Death Pathways

Lung cancer is one of the leading causes of death worldwide. Cell death pathways such as autophagy, apoptosis, and necrosis can provide useful clinical and immunological insights that can assist in the design of personalized therapeutics. In this study, variations in the expression of genes involved in cell death pathways and resulting infiltration of immune cells were explored in lung adenocarcinoma (The Cancer Genome Atlas: TCGA, lung adenocarcinoma (LUAD), 510 patients). Firstly, genes involved in autophagy (n = 34 genes), apoptosis (n = 66 genes), and necrosis (n = 32 genes) were analyzed to assess the prognostic significance in lung cancer. The significant genes were used to develop the cell death index (CDI) of 21 genes which clustered patients based on high risk (high CDI) and low risk (low CDI). The survival analysis using the Kaplan–Meier curve differentiated patients based on overall survival (40.4 months vs. 76.2 months), progression-free survival (26.2 months vs. 48.6 months), and disease-free survival (62.2 months vs. 158.2 months) (Log-rank test, p < 0.01). Cox proportional hazard model significantly associated patients in high CDI group with a higher risk of mortality (Hazard Ratio: H.R 1.75, 95% CI: 1.28–2.45, p < 0.001). Differential gene expression analysis using principal component analysis (PCA) identified genes with the highest fold change forming distinct clusters. To analyze the immune parameters in two risk groups, cytokines expression (n = 265 genes) analysis revealed the highest association of IL-15RA and IL 15 (> 1.5-fold, p < 0.01) with the high-risk group. The microenvironment cell-population (MCP)-counter algorithm identified the higher infiltration of CD8+ T cells, macrophages, and lower infiltration of neutrophils with the high-risk group. Interestingly, this group also showed a higher expression of immune checkpoint molecules CD-274 (PD-L1), CTLA-4, and T cell exhaustion genes (HAVCR2, TIGIT, LAG3, PDCD1, CXCL13, and LYN) (p < 0.01). Furthermore, functional enrichment analysis identified significant perturbations in immune pathways in the higher risk group. This study highlights the presence of an immunocompromised microenvironment indicated by the higher infiltration of cytotoxic T cells along with the presence of checkpoint molecules and T cell exhaustion genes. These patients at higher risk might be more suitable to benefit from PD-L1 blockade or other checkpoint blockade immunotherapies.

scholarly journals Type I interferons affect the metabolic fitness of CD8+ T cells from patients with systemic lupus erythematosus

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Norzawani Buang ◽  
Lunnathaya Tapeng ◽  
Victor Gray ◽  
Alessandro Sardini ◽  
Chad Whilding ◽  
...  
Keyword(s):  
Systemic Lupus Erythematosus ◽  
T Cells ◽  
Cell Death ◽  
T Cell ◽  
Lupus Erythematosus ◽  
Type I Interferons ◽  
Type I ◽  
Type I Ifn ◽  
Systemic Lupus ◽  
Mitochondrial Abnormalities

AbstractThe majority of patients with systemic lupus erythematosus (SLE) have high expression of type I IFN-stimulated genes. Mitochondrial abnormalities have also been reported, but the contribution of type I IFN exposure to these changes is unknown. Here, we show downregulation of mitochondria-derived genes and mitochondria-associated metabolic pathways in IFN-High patients from transcriptomic analysis of CD4+ and CD8+ T cells. CD8+ T cells from these patients have enlarged mitochondria and lower spare respiratory capacity associated with increased cell death upon rechallenge with TCR stimulation. These mitochondrial abnormalities can be phenocopied by exposing CD8+ T cells from healthy volunteers to type I IFN and TCR stimulation. Mechanistically these ‘SLE-like’ conditions increase CD8+ T cell NAD+ consumption resulting in impaired mitochondrial respiration and reduced cell viability, both of which can be rectified by NAD+ supplementation. Our data suggest that type I IFN exposure contributes to SLE pathogenesis by promoting CD8+ T cell death via metabolic rewiring.

549 Characterizing double positive T cells in the tumor microenvironment: a tale of promiscuous cell fates

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A586-A586
Author(s):  
Sara Schad ◽  
Andrew Chow ◽  
Heng Pan ◽  
Levi Mangarin ◽  
Roberta Zappasodi ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Tumor Microenvironment ◽  
Cd8 T Cells ◽  
Human Melanoma ◽  
B16 Melanoma ◽  
T Cell Subsets ◽  
Double Positive ◽  
Cell Fates ◽  
Single Positive

BackgroundCD4 and CD8 T cells are genetically and functionally distinct cell subsets of the adaptive immune system that play pivotal roles in immune surveillance and disease control. During development in the thymus, transcription factors ThPOK and Runx3 regulate the differentiation and maturation of these two lineages into single positive T cells that enter the periphery with mutually exclusive expression of either the CD4 or CD8 co-receptor.1–2 Despite our expectation that these two cell fates are fixed, mature CD4+CD8+ double positive (DP) T cells have been described in the context of numerous immunological responses, including cancer, but their molecular and functional properties and therapeutic relevance remain controversial and largely unknown.3–5MethodsOur lab has identified and characterized a heterogenous DP T cell population in murine and human melanoma tumors comprised of CD4 and CD8 T cells re-expressing the opposite co-receptor and a parallel uptake in the opposite cell type’s phenotype and function. Using CD4 (Trp1) and CD8 (Pmel) transgenic TCR T cells specific to B16 melanoma antigens gp75 and gp100 respectively, we demonstrate the re-expression of the opposite co-receptor following adoptive T cell transfer in B16 melanoma tumor bearing mice.ResultsSpecifically, up to 50% of transferred CD4 Trp1 T cells will re-express CD8 to become a DP T cell in the tumor microenvironment. Further, these CD4 derived DP T cells upregulate CD8 lineage regulator Runx3 and cytolytic genes Gzmb, Gzmk, and Prf1 to become potent cytotoxic T cells. Alternatively, a subset of CD8 Pmel T cells differentiate into DP T cells characterized by the increased expression of CD4, ThPOK, and regulatory marker FoxP3 (figure 1). In addition, we utilized 10x single cell and ATAC sequencing to further characterize these divergent DP T cell populations among open repertoire T cells isolated from murine and human melanoma tumors.ConclusionsOur findings highlight the capability of single positive T cells to differentiate in response to antigen and local stimuli into novel T cell subsets with polyfunctional characteristics. The resulting cell subsets will potentially affect the tumor microenvironment in distinct ways. Our studies may inform therapeutic approaches to identify antigen specific T cells as well as innovative signaling pathways to target when genetically engineering T cells to optimize cytotoxic function in the setting of adoptive cell therapy.Ethics ApprovalThe human biospecimen analyses were approved by Memorial Sloan Kettering Cancer Center IRB #06-107ReferencesEllmeier W, Haust L & Tschismarov R. Transcriptional control of CD4 and CD8 coreceptor expression during T cell development. Cell Mol Life Sci 2013;70:4537–4553.Luckey MA, et al. The transcription factor ThPOK suppresses Runx3 and imposes CD4+ lineage fate by inducing the SOCS suppressors of cytokine signaling. Nature Immunology 2014; 15, 638–645.Bohner P, et al. Double positive CD4(+)CD8(+) T Cells are enriched in urological cancers and favor T Helper-2 polarization. Front Immunol 2019; 10, 622.Nascimbeni M, Shin E-C, Chiriboga L, Kleiner DE & Rehermann B. Peripheral CD4(+)CD8(+) T cells are differentiated effector memory cells with antiviral functions. Blood 2004;104:478–486.Nishida K, et al. Clinical importance of the expression of CD4+CD8+ T cells in renal cell carcinoma. Int Immunol 2020;32:347–357.

Susceptibility to cell death is a dominant phenotype: triggering of activation-driven T-cell death independent of the T-cell antigen receptor complex

1992 ◽  
Vol 12 (1) ◽  
pp. 379-385
Author(s):  
G Nickas ◽  
J Meyers ◽  
L D Hebshi ◽  
J D Ashwell ◽  
D P Gold ◽  
...  
Keyword(s):  
T Cells ◽  
Cell Death ◽  
T Cell ◽  
Interleukin 2 ◽  
Antigen Receptor ◽  
Alternative Activation ◽  
Receptor Complex ◽  
T Cell Antigen Receptor ◽  
Cell Antigen Receptor ◽  
Cell Antigen

The failure of Thy-1 and Ly-6 to trigger interleukin-2 production in the absence of surface T-cell antigen receptor complex (TCR) expression has been interpreted to suggest that functional signalling via these phosphatidylinositol-linked alternative activation molecules is dependent on the TCR. We find, in contrast, that stimulation of T cells via Thy-1 or Ly-6 in the absence of TCR expression does trigger a biological response, the cell suicide process of activation-driven cell death. Activation-driven cell death is a process of physiological cell death that likely represents the mechanism of negative selection of T cells. The absence of the TCR further reveals that signalling leading to activation-driven cell death and to lymphokine production are distinct and dissociable. In turn, the ability of alternative activation molecules to function in the absence of the TCR raises another issue: why immature T cells, thymomas, and hybrids fail to undergo activation-driven cell death in response to stimulation via Thy-1 and Ly-6. One possibility is that these activation molecules on immature T cells are defective. Alternatively, susceptibility to activation-driven cell death may be developmentally regulated by TCR-independent factors. We have explored these possibilities with somatic cell hybrids between mature and immature T cells, in which Thy-1 and Ly-6 are contributed exclusively by the immature partner. The hybrid cells exhibit sensitivity to activation-driven cell death triggered via Thy-1 and Ly-6. Thus, the Thy-1 and Ly-6 molecules of the immature T cells can function in a permissive environment. Moreover, with regard to susceptibility to Thy-1 and Ly-6 molecules of the immature T cells can function in a permissive environment. Moreover, with regard to susceptibility to Thy-1 and Ly-6 triggering, the mature phenotype of sensitivity to cell death is genetically dominant.

Altered thymocyte and T cell development in neonatal mice with hyperoxia-induced lung injury

2018 ◽  
Vol 46 (4) ◽  
pp. 441-449
Author(s):  
Sowmya Angusamy ◽  
Tamer Mansour ◽  
Mohammed Abdulmageed ◽  
Rachel Han ◽  
Brian C. Schutte ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Lung Injury ◽  
T Cell Development ◽  
Adaptive Immune System ◽  
Cell Development ◽  
Thymocyte Development ◽  
Double Positive ◽  
Neonatal Mice ◽  
Single Positive

Abstract Background: The adaptive immune system of neonates is relatively underdeveloped. The thymus is an essential organ for adaptive T cell development and might be affected during the natural course of oxygen induced lung injury. The effect of prolonged hyperoxia on the thymus, thymocyte and T cell development, and its proliferation has not been studied extensively. Methods: Neonatal mice were exposed to 85% oxygen (hyperoxia) or room air (normoxia) up to 28 days. Flow cytometry using surface markers were used to assay for thymocyte development and proliferation. Results: Mice exposed to prolonged hyperoxia had evidence of lung injury associated alveolar simplification, a significantly lower mean weight, smaller thymic size, lower mean thymocyte count and higher percentage of apoptotic thymocytes. T cells subpopulation in the thymus showed a significant reduction in the count and proliferation of double positive and double negative T cells. There was a significant reduction in the count and proliferation of single positive CD4+ and CD8+ T cells. Conclusions: Prolonged hyperoxia in neonatal mice adversely affected thymic size, thymocyte count and altered the distribution of T cells sub-populations. These results are consistent with the hypothesis that prolonged hyperoxia causes defective development of T cells in the thymus.

Combination cancer immunotherapy targeting PD-1 and GITR can rescue CD8+T cell dysfunction and maintain memory phenotype

2018 ◽  
Vol 3 (29) ◽  
pp. eaat7061 ◽  
Author(s):  
Bei Wang ◽  
Wen Zhang ◽  
Vladimir Jankovic ◽  
Jacquelynn Golubov ◽  
Patrick Poon ◽  
...  
Keyword(s):  
T Cells ◽  
Cell Death ◽  
T Cell ◽  
Programmed Cell Death ◽  
Cancer Immunotherapy ◽  
Effector Memory ◽  
Cell Phenotype ◽  
Checkpoint Inhibition ◽  
Cell Dysfunction ◽  
T Cell Dysfunction

Most patients with cancer do not develop durable antitumor responses after programmed cell death protein 1 (PD-1) or programmed cell death ligand 1(PD-L1) checkpoint inhibition monotherapy because of an ephemeral reversal of T cell dysfunction and failure to promote long-lasting immunological T cell memory. Activating costimulatory pathways to induce stronger T cell activation may improve the efficacy of checkpoint inhibition and lead to durable antitumor responses. We performed single-cell RNA sequencing of more than 2000 tumor-infiltrating CD8+T cells in mice receiving both PD-1 and GITR (glucocorticoid-induced tumor necrosis factor receptor–related protein) antibodies and found that this combination synergistically enhanced the effector function of expanded CD8+T cells by restoring the balance of key homeostatic regulators CD226 and T cell immunoreceptor with Ig and ITIM domains (TIGIT), leading to a robust survival benefit. Combination therapy decreased CD8+T cell dysfunction and induced a highly proliferative precursor effector memory T cell phenotype in a CD226-dependent manner. PD-1 inhibition rescued CD226 activity by preventing PD-1–Src homology region 2 (SHP2) dephosphophorylation of the CD226 intracellular domain, whereas GITR agonism decreased TIGIT expression. Unmasking the molecular pathways driving durable antitumor responses will be essential to the development of rational approaches to optimizing cancer immunotherapy.

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