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Kumar A, Ye C, Nkansah A, Decoville T, Fogo GM, Sajjakulnukit P, Reynolds MB, Zhang L, Quaye O, Seo YA, Sanderson TH, Lyssiotis CA, Chang CH. Iron regulates the quiescence of naive CD4 T cells by controlling mitochondria and cellular metabolism. Proc Natl Acad Sci U S A 2024; 121:e2318420121. [PMID: 38621136 PMCID: PMC11047099 DOI: 10.1073/pnas.2318420121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2023] [Accepted: 03/14/2024] [Indexed: 04/17/2024] Open
Abstract
In response to an immune challenge, naive T cells undergo a transition from a quiescent to an activated state acquiring the effector function. Concurrently, these T cells reprogram cellular metabolism, which is regulated by iron. We and others have shown that iron homeostasis controls proliferation and mitochondrial function, but the underlying mechanisms are poorly understood. Given that iron derived from heme makes up a large portion of the cellular iron pool, we investigated iron homeostasis in T cells using mice with a T cell-specific deletion of the heme exporter, FLVCR1 [referred to as knockout (KO)]. Our finding revealed that maintaining heme and iron homeostasis is essential to keep naive T cells in a quiescent state. KO naive CD4 T cells exhibited an iron-overloaded phenotype, with increased spontaneous proliferation and hyperactive mitochondria. This was evidenced by reduced IL-7R and IL-15R levels but increased CD5 and Nur77 expression. Upon activation, however, KO CD4 T cells have defects in proliferation, IL-2 production, and mitochondrial functions. Iron-overloaded CD4 T cells failed to induce mitochondrial iron and exhibited more fragmented mitochondria after activation, making them susceptible to ferroptosis. Iron overload also led to inefficient glycolysis and glutaminolysis but heightened activity in the hexosamine biosynthetic pathway. Overall, these findings highlight the essential role of iron in controlling mitochondrial function and cellular metabolism in naive CD4 T cells, critical for maintaining their quiescent state.
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Affiliation(s)
- Ajay Kumar
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI48109
| | - Chenxian Ye
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI48109
| | - Afia Nkansah
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI48109
- Department of Biochemistry, Cell and Molecular Biology, West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, AccraG4522, Ghana
| | - Thomas Decoville
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI48109
| | - Garrett M. Fogo
- Department of Emergency Medicine, University of Michigan Medical School, Ann Arbor, MI48109
| | - Peter Sajjakulnukit
- Rogel Cancer Center, University of Michigan Medical School, Ann Arbor, MI48109
| | - Mack B. Reynolds
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI48109
| | - Li Zhang
- Rogel Cancer Center, University of Michigan Medical School, Ann Arbor, MI48109
| | - Osbourne Quaye
- Department of Biochemistry, Cell and Molecular Biology, West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, AccraG4522, Ghana
| | - Young-Ah Seo
- Department of Nutritional Sciences, University of Michigan School of Public Health, Ann Arbor, MI48109
| | - Thomas H. Sanderson
- Department of Emergency Medicine, University of Michigan Medical School, Ann Arbor, MI48109
- Department of Internal Medicine, Division of Gastroenterology and Hepatology, University of Michigan Medical School, Ann Arbor, MI48109
| | - Costas A. Lyssiotis
- Rogel Cancer Center, University of Michigan Medical School, Ann Arbor, MI48109
- Department of Internal Medicine, Division of Gastroenterology and Hepatology, University of Michigan Medical School, Ann Arbor, MI48109
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI48109
| | - Cheong-Hee Chang
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI48109
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Machado MP, dos Santos MH, Guimarães JG, de Campos GY, Oliveira Brito PKM, Ferreira CMG, Rezende CP, Frota NF, Soares SG, Kumaresan PR, Lourenzoni MR, da Silva TA. GXMR-CAR containing distinct GXM-specific single-chain variable fragment (scFv) mediated the cell activation against Cryptococcus spp. And had difference in the strength of tonic signaling. Bioengineered 2023; 14:2281059. [PMID: 37978838 PMCID: PMC10761124 DOI: 10.1080/21655979.2023.2281059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Accepted: 11/02/2023] [Indexed: 11/19/2023] Open
Abstract
Cryptococcus spp. has a polysaccharide capsule composed of glucuronoxylomannan-GXM, a major virulence factor that can prevent the recognition of fungi by immune cells. Chimeric Antigen Receptor (CAR) redirects T cells to target Cryptococcus spp. as previously demonstrated by a CAR specific to GXM, GXMR-CAR. The current study evaluated the strength of the signal transduction triggered by GXMR-CAR, composed of a distinct antigen-binding domain sourced from a single-chain variable fragment (scFv). GXM-specific scFv derived from mAbs 2H1 and 18B7, 2H1-GXMR-CAR and 18B7-GXMR-CAR, respectively, were designed to express CD8 molecule as hinge/transmembrane, and the costimulatory molecule CD137 (4-1BB) coupled to CD3ζ. The 2H1-GXMR-CAR or 18B7-GXMR-CAR Jurkat cells recognized soluble GXM from C. gattii and C. neoformans, and the levels of IL-2 released by the modified cells did not differ between the GXMR-CAR constructs after exposure to Cryptococcus spp. 18B7-GXMR-CAR triggered tonic signaling was more pronounced in modified Jurkat cells, and a protein kinase inhibitor of the Src family (dasatinib) significantly reduced GXMR-CAR tonic signaling and inhibited cell activation against ligands. 18B7 scFv showed a structural modification of the variable heavy (VH) chain that clarified the difference in the strength of tonic signaling and the level of cell activation between 2H1-GXMR-CAR and 18B7-GXMR-CAR. GXMR-CAR constructs induced T-cell activation against clinical isolates of Cryptococcus spp. and serum from patients with cryptococcosis induced high levels of IL-2, mainly in cells modified with 18B7-GXMR-CAR. Thus, 18B7-GXMR-CAR and 2H1-GXMR-CAR mediated T cell activation against Cryptococcus spp. and 18B7 and 2H1 scFv influenced the strength of tonic signaling.
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Affiliation(s)
- Michele Procópio Machado
- Department of Cellular and Molecular Biology, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao, Sao Paulo, Brazil
| | - Matheus Henrique dos Santos
- Department of Cellular and Molecular Biology, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao, Sao Paulo, Brazil
| | - Júlia Garcia Guimarães
- Department of Cellular and Molecular Biology, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao, Sao Paulo, Brazil
| | - Gabriela Yamazaki de Campos
- Department of Cellular and Molecular Biology, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao, Sao Paulo, Brazil
| | | | - Camilly Melo Garcia Ferreira
- Department of Cellular and Molecular Biology, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao, Sao Paulo, Brazil
| | - Caroline Patini Rezende
- Department of Biochemistry and Immunology, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao, Sao Paulo, Brazil
| | | | | | - Pappanaicken R. Kumaresan
- Department of Hematopoietic Biology and Malignancy, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Marcos Roberto Lourenzoni
- Fundação Oswaldo Cruz Ceará (Fiocruz-CE), Research Group on Protein Engineering and Health Solutions (GEPeSS), Eusébio, Ceara, Brazil
| | - Thiago Aparecido da Silva
- Department of Cellular and Molecular Biology, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao, Sao Paulo, Brazil
- Department of Clinical Analysis, School of Pharmaceutical Sciences in Araraquara, Sao Paulo State University, Araraquara, Sao Paulo, Brazil
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3
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Hou P, Zielonka M, Serneels L, Martinez-Muriana A, Fattorelli N, Wolfs L, Poovathingal S, T'Syen D, Balusu S, Theys T, Fiers M, Mancuso R, Howden AJM, De Strooper B. The γ-secretase substrate proteome and its role in cell signaling regulation. Mol Cell 2023; 83:4106-4122.e10. [PMID: 37977120 DOI: 10.1016/j.molcel.2023.10.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 06/22/2023] [Accepted: 10/20/2023] [Indexed: 11/19/2023]
Abstract
γ-Secretases mediate the regulated intramembrane proteolysis (RIP) of more than 150 integral membrane proteins. We developed an unbiased γ-secretase substrate identification (G-SECSI) method to study to what extent these proteins are processed in parallel. We demonstrate here parallel processing of at least 85 membrane proteins in human microglia in steady-state cell culture conditions. Pharmacological inhibition of γ-secretase caused substantial changes of human microglial transcriptomes, including the expression of genes related to the disease-associated microglia (DAM) response described in Alzheimer disease (AD). While the overall effects of γ-secretase deficiency on transcriptomic cell states remained limited in control conditions, exposure of mouse microglia to AD-inducing amyloid plaques strongly blocked their capacity to mount this putatively protective DAM cell state. We conclude that γ-secretase serves as a critical signaling hub integrating the effects of multiple extracellular stimuli into the overall transcriptome of the cell.
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Affiliation(s)
- Pengfei Hou
- Laboratory for the Research of Neurodegenerative Diseases, VIB Center for Brain & Disease Research, VIB, Leuven 3000, Belgium; Department of Neurosciences and Leuven Brain Institute, KU Leuven, Leuven 3000, Belgium
| | - Magdalena Zielonka
- Laboratory for the Research of Neurodegenerative Diseases, VIB Center for Brain & Disease Research, VIB, Leuven 3000, Belgium; Department of Neurosciences and Leuven Brain Institute, KU Leuven, Leuven 3000, Belgium
| | - Lutgarde Serneels
- Laboratory for the Research of Neurodegenerative Diseases, VIB Center for Brain & Disease Research, VIB, Leuven 3000, Belgium; Department of Neurosciences and Leuven Brain Institute, KU Leuven, Leuven 3000, Belgium
| | - Anna Martinez-Muriana
- Laboratory for the Research of Neurodegenerative Diseases, VIB Center for Brain & Disease Research, VIB, Leuven 3000, Belgium; Department of Neurosciences and Leuven Brain Institute, KU Leuven, Leuven 3000, Belgium
| | - Nicola Fattorelli
- Laboratory for the Research of Neurodegenerative Diseases, VIB Center for Brain & Disease Research, VIB, Leuven 3000, Belgium; Department of Neurosciences and Leuven Brain Institute, KU Leuven, Leuven 3000, Belgium
| | - Leen Wolfs
- Laboratory for the Research of Neurodegenerative Diseases, VIB Center for Brain & Disease Research, VIB, Leuven 3000, Belgium; Department of Neurosciences and Leuven Brain Institute, KU Leuven, Leuven 3000, Belgium
| | - Suresh Poovathingal
- Department of Neurosciences and Leuven Brain Institute, KU Leuven, Leuven 3000, Belgium; Single Cell & Microfluidics Expertise Unit, VIB Center for Brain & Disease Research, VIB, Leuven 3000, Belgium
| | - Dries T'Syen
- Laboratory for the Research of Neurodegenerative Diseases, VIB Center for Brain & Disease Research, VIB, Leuven 3000, Belgium; Department of Neurosciences and Leuven Brain Institute, KU Leuven, Leuven 3000, Belgium
| | - Sriram Balusu
- Laboratory for the Research of Neurodegenerative Diseases, VIB Center for Brain & Disease Research, VIB, Leuven 3000, Belgium; Department of Neurosciences and Leuven Brain Institute, KU Leuven, Leuven 3000, Belgium
| | - Tom Theys
- Department of Neurosciences, Research Group Experimental Neurosurgery and Neuroanatomy, KU Leuven, Leuven 3000, Belgium
| | - Mark Fiers
- Laboratory for the Research of Neurodegenerative Diseases, VIB Center for Brain & Disease Research, VIB, Leuven 3000, Belgium; Department of Neurosciences and Leuven Brain Institute, KU Leuven, Leuven 3000, Belgium; Center for Human Genetics, KU Leuven, Leuven 3000, Belgium; Dementia Research Institute, Institute of Neurology, University College London, London WC1E 6BT, UK
| | - Renzo Mancuso
- Microglia and Inflammation in Neurological Disorders (MIND) Lab, VIB Center for Molecular Neurology, VIB, Antwerp 2610, Belgium; Department of Biomedical Sciences, University of Antwerp, Antwerp 2610, Belgium
| | - Andrew J M Howden
- Division of Cell Signaling and Immunology, School of Life Sciences, University of Dundee, Dundee DD1 4HN, UK
| | - Bart De Strooper
- Laboratory for the Research of Neurodegenerative Diseases, VIB Center for Brain & Disease Research, VIB, Leuven 3000, Belgium; Department of Neurosciences and Leuven Brain Institute, KU Leuven, Leuven 3000, Belgium; Center for Human Genetics, KU Leuven, Leuven 3000, Belgium; Dementia Research Institute, Institute of Neurology, University College London, London WC1E 6BT, UK.
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4
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Zhu X, Li Q, Zhu X. Mechanisms of CAR T cell exhaustion and current counteraction strategies. Front Cell Dev Biol 2022; 10:1034257. [PMID: 36568989 PMCID: PMC9773844 DOI: 10.3389/fcell.2022.1034257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Accepted: 11/24/2022] [Indexed: 12/13/2022] Open
Abstract
The functional state of chimeric antigen receptor T (CAR T) cells determines their efficacy in vivo. Exhausted CAR T cells exhibit decreased proliferative capacity, impaired anti-tumor activity, and attenuated persistence. CAR T cell exhaustion has been recognized as a vital cause of nonresponse and relapse after CAR T cell therapy. However, the triggers and mechanisms leading to CAR T cell exhaustion remain blurry and complicated. Therefore, it is essential to clear the regulation network of CAR T cell exhaustion and explore potent solutions. Here, we review the diverse inducers of CAR T cell exhaustion in terms of manufacture process and immunosuppressive tumor microenvironment. In addition to the admitted immune checkpoint blockade, we also describe promising strategies that may reverse CAR T cell exhaustion including targeting the tumor microenvironment, epigenetics and transcriptomics.
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Affiliation(s)
- Xiaoying Zhu
- Department of Hematology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Qing Li
- Department of Hematology, Wuhan No. 1 Hospital, Wuhan, China,*Correspondence: Qing Li, ; Xiaojian Zhu,
| | - Xiaojian Zhu
- Department of Hematology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China,*Correspondence: Qing Li, ; Xiaojian Zhu,
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5
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Abstract
The manufacture of efficacious CAR T cells represents a major challenge in cellular therapy. An important aspect of their quality concerns energy production and consumption, known as metabolism. T cells tend to adopt diverse metabolic profiles depending on their differentiation state and their stimulation level. It is therefore expected that the introduction of a synthetic molecule such as CAR, activating endogenous signaling pathways, will affect metabolism. In addition, upon patient treatment, the tumor microenvironment might influence the CAR T cell metabolism by compromising the energy resources. The access to novel technology with higher throughput and reduced cost has led to an increased interest in studying metabolism. Indeed, methods to quantify glycolysis and mitochondrial respiration have been available for decades but were rarely applied in the context of CAR T cell therapy before the release of the Seahorse XF apparatus. The present review will focus on the use of this instrument in the context of studies describing the impact of CAR on T cell metabolism and the strategies to render of CAR T cells more metabolically fit.
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Affiliation(s)
- Christopher Forcados
- Translational Research Unit, Department of Cellular Therapy, Oslo University Hospital, 0379 Oslo, Norway; (C.F.); (S.J.); (N.P.C.); (B.C.)
| | - Sandy Joaquina
- Translational Research Unit, Department of Cellular Therapy, Oslo University Hospital, 0379 Oslo, Norway; (C.F.); (S.J.); (N.P.C.); (B.C.)
| | - Nicholas Paul Casey
- Translational Research Unit, Department of Cellular Therapy, Oslo University Hospital, 0379 Oslo, Norway; (C.F.); (S.J.); (N.P.C.); (B.C.)
| | - Benjamin Caulier
- Translational Research Unit, Department of Cellular Therapy, Oslo University Hospital, 0379 Oslo, Norway; (C.F.); (S.J.); (N.P.C.); (B.C.)
- Center for Cancer Cell Reprogramming (CanCell), Institute for Clinical Medicine, Faculty of Medicine, University of Oslo, 0372 Oslo, Norway
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, 0379 Oslo, Norway
| | - Sébastien Wälchli
- Translational Research Unit, Department of Cellular Therapy, Oslo University Hospital, 0379 Oslo, Norway; (C.F.); (S.J.); (N.P.C.); (B.C.)
- Correspondence:
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Webster B, Xiong Y, Hu P, Wu D, Alabanza L, Orentas RJ, Dropulic B, Schneider D. Self-driving armored CAR-T cells overcome a suppressive milieu and eradicate CD19 + Raji lymphoma in preclinical models. Mol Ther 2021; 29:2691-706. [PMID: 33974997 DOI: 10.1016/j.ymthe.2021.05.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 02/08/2021] [Accepted: 05/05/2021] [Indexed: 11/20/2022] Open
Abstract
Chimeric antigen receptor (CAR) T cells typically use a strong constitutive promoter to ensure maximal long-term CAR expression. However, recent evidence suggests that restricting the timing and magnitude of CAR expression is functionally beneficial, whereas constitutive CAR activation may lead to exhaustion and loss of function. We created a self-driving CD19-targeting CAR, which regulates its own function based on the presence of a CD19 antigen engaged by the CAR itself, by placing self-driving CAR19 constructs under transcriptional control of synthetic activator protein 1 (AP1)-nuclear factor κB (NF-κB) or signal transducer and activator of transcription (STAT)5 promoters. CD19 antigen-regulated expression was observed for self-driving AP1-NFκB-CAR19, with CAR19 upregulation within 18 h after exposure to target CD19, and corresponded to the level of tumor burden. Self-driving CAR-T cells showed enhanced tumor-dependent activation, expansion, and low exhaustion in vitro as compared to constitutively expressed EF1α and murine stem cell virus (MSCV) CARs and mediated tumor regression and survival in Raji-bearing NOD.Cg-PrkdcscidIl2rgtm1Wjl/SzJ (NSG) mice. Long-term CAR function correlated with upregulated CAR expression within 24 h of exposure to tumor antigen. The self-driving AP1-NFκB-CAR19 circuit was also used to inducibly express dominant-negative transforming growth factor β receptor II (TGFBRIIdn), which effectively countered the negative effects of TGF-β on CAR-T activation. Thus, a self-driving CAR approach may offer a new modality to express CAR and auxiliary proteins by enhancing CAR-T functional activity and limiting exhaustion.
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Zajc CU, Salzer B, Taft JM, Reddy ST, Lehner M, Traxlmayr MW. Driving CARs with alternative navigation tools - the potential of engineered binding scaffolds. FEBS J 2020; 288:2103-2118. [PMID: 32794303 PMCID: PMC8048499 DOI: 10.1111/febs.15523] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Revised: 07/31/2020] [Accepted: 08/08/2020] [Indexed: 12/11/2022]
Abstract
T cells that are genetically engineered to express chimeric antigen receptors (CAR T cells) have shown impressive clinical efficacy against B‐cell malignancies. In contrast to these highly potent CD19‐targeting CAR T cells, many of those directed against other tumor entities and antigens currently suffer from several limitations. For example, it has been demonstrated that many scFvs used as antigen‐binding domains in CARs show some degree of oligomerization, which leads to tonic signaling, T cell exhaustion, and poor performance in vivo. Therefore, in many cases alternatives to scFvs would be beneficial. Fortunately, due to the development of powerful protein engineering technologies, also non‐immunoglobulin‐based scaffolds can be engineered to specifically recognize antigens, thus eliminating the historical dependence on antibody‐based binding domains. Here, we discuss the advantages and disadvantages of such engineered binding scaffolds, in particular with respect to their application in CARs. We review recent studies, collectively showing that there is no functional or biochemical aspect that necessitates the use of scFvs in CARs. Instead, antigen recognition can also be mediated efficiently by engineered binding scaffolds, as well as natural ligands or receptors fused to the CAR backbone. Finally, we critically discuss the risk of immunogenicity and show that the extent of nonhuman amino acid stretches in engineered scaffolds—even in those based on nonhuman proteins—is more similar to humanized scFvs than might be anticipated. Together, we expect that engineered binding scaffolds and natural ligands and receptors will be increasingly used for the design of CAR T cells.
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Affiliation(s)
- Charlotte U Zajc
- Christian Doppler Laboratory for Next Generation CAR T Cells, Vienna, Austria.,Department of Chemistry, Institute of Biochemistry, BOKU-University of Natural Resources and Life Sciences, Vienna, Austria
| | - Benjamin Salzer
- Christian Doppler Laboratory for Next Generation CAR T Cells, Vienna, Austria.,St. Anna Children's Cancer Research Institute, Vienna, Austria
| | - Joseph M Taft
- Department of Biosystems Science and Engineering, ETH Zurich, Basel, Switzerland
| | - Sai T Reddy
- Department of Biosystems Science and Engineering, ETH Zurich, Basel, Switzerland
| | - Manfred Lehner
- Christian Doppler Laboratory for Next Generation CAR T Cells, Vienna, Austria.,St. Anna Children's Cancer Research Institute, Vienna, Austria.,Department of Pediatrics, St. Anna Kinderspital, Medical University of Vienna, Austria
| | - Michael W Traxlmayr
- Christian Doppler Laboratory for Next Generation CAR T Cells, Vienna, Austria.,Department of Chemistry, Institute of Biochemistry, BOKU-University of Natural Resources and Life Sciences, Vienna, Austria
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8
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Myers DR, Norlin E, Vercoulen Y, Roose JP. Active Tonic mTORC1 Signals Shape Baseline Translation in Naive T Cells. Cell Rep 2020; 27:1858-1874.e6. [PMID: 31067469 PMCID: PMC6593126 DOI: 10.1016/j.celrep.2019.04.037] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2018] [Revised: 01/25/2019] [Accepted: 04/05/2019] [Indexed: 12/15/2022] Open
Abstract
Naive CD4+ T cells are an example of dynamic cell homeostasis: T cells need to avoid autoreactivity while constantly seeing self-peptides, yet they must be primed to react to foreign antigens during infection. The instructive signals that balance this primed yet quiescent state are unknown. Interactions with self-peptides result in membrane-proximal, tonic signals in resting T cells. Here we reveal selective and robust tonic mTORC1 signals in CD4+ T cells that influence T cell fate decisions. We find that the Ras exchange factor Rasgrp1 is necessary to generate tonic mTORC1 signals. Genome-wide ribosome profiling of resting, primary CD4+ T cells uncovers a baseline translational landscape rich in mTOR targets linked to mitochondria, oxidative phosphorylation, and splicing. Aberrantly increased tonic mTORC1 signals from a Rasgrp1Anaef allele result in immunopathology with spontaneous appearance of T peripheral helper cells, follicular helper T cells, and anti-nuclear antibodies that are preceded by subtle alterations in the translational landscape. Myers et al. evaluate a mouse model of autoimmunity, Rasgrp1Anaef. They find that T cells with the Rasgrp1Anaef allele exhibit altered signaling from Rasgrp1 to the mTORC1 pathway in the basal state. They show that increased basal Rasgrp1Anaef-mTORC1 signals lead to an altered translational landscape in T cells and immunopathology.
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Affiliation(s)
- Darienne R Myers
- Department of Anatomy, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Emilia Norlin
- Department of Anatomy, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Yvonne Vercoulen
- Department of Anatomy, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Jeroen P Roose
- Department of Anatomy, University of California, San Francisco, San Francisco, CA 94143, USA.
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9
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Abstract
Nonclonal innate immune responses mediated by germ line-encoded receptors, such as Toll-like receptors or natural killer receptors, are commonly contrasted with diverse, clonotypic adaptive responses of lymphocyte antigen receptors generated by somatic recombination. However, the Variable (V) regions of antigen receptors include germ line-encoded motifs unaltered by somatic recombination, and theoretically available to mediate nonclonal, innate responses, that are independent of or largely override clonotypic responses. Recent evidence demonstrates that such responses exist, underpinning the associations of particular γδ T cell receptors (TCRs) with specific anatomical sites. Thus, TCRγδ can make innate and adaptive responses with distinct functional outcomes. Given that αβ T cells and B cells can also make nonclonal responses, we consider that innate responses of antigen receptor V-regions may be more widespread, for example, inducing states of preparedness from which adaptive clones are better selected. We likewise consider that potent, nonclonal T cell responses to microbial superantigens may reflect subversion of physiologic innate responses of TCRα/β chains.
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Affiliation(s)
- Adrian C Hayday
- Peter Gorer Department of Immunobiology, King's College, London, SE1 9RT, United Kingdom; .,Immunosurveillance Laboratory, Francis Crick Institute, London, NW1 1AT, United Kingdom
| | - Pierre Vantourout
- Peter Gorer Department of Immunobiology, King's College, London, SE1 9RT, United Kingdom; .,Immunosurveillance Laboratory, Francis Crick Institute, London, NW1 1AT, United Kingdom
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10
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Myers DR, Zikherman J, Roose JP. Tonic Signals: Why Do Lymphocytes Bother? Trends Immunol 2017; 38:844-857. [PMID: 28754596 DOI: 10.1016/j.it.2017.06.010] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Revised: 06/23/2017] [Accepted: 06/27/2017] [Indexed: 01/09/2023]
Abstract
Since the 1990s it has been known that B and T lymphocytes exhibit low-level, constitutive signaling in the basal state (tonic signaling). These lymphocytes display a range of affinity for self, which in turn generates a range of tonic signaling. Surprisingly, what signaling pathways are active in the basal state and the functional relevance of the observed tonic signaling heterogeneity remain open questions today. Here we summarize what is known about the mechanistic and functional details of tonic signaling. We highlight recent advances that have increased our understanding of how the amount of tonic signal impacts immune function, describing novel tools that have moved the field forward and toward a molecular understanding of tonic signaling.
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Affiliation(s)
- Darienne R Myers
- Department of Anatomy, School of Medicine, University of California, San Francisco, CA 94143, USA
| | - Julie Zikherman
- Division of Rheumatology, Rosalind Russell and Ephraim P. Engleman Arthritis Research Center, Department of Medicine, University of California, San Francisco, CA 94143, USA
| | - Jeroen P Roose
- Department of Anatomy, School of Medicine, University of California, San Francisco, CA 94143, USA.
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