1
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Fathman CG, Yip L, Gómez-Martín D, Yu M, Seroogy CM, Hurt CR, Lin JT, Jenks JA, Nadeau KC, Soares L. How GRAIL controls Treg function to maintain self-tolerance. Front Immunol 2022; 13:1046631. [PMID: 36569931 PMCID: PMC9773990 DOI: 10.3389/fimmu.2022.1046631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Accepted: 11/21/2022] [Indexed: 12/14/2022] Open
Abstract
Regulatory T cells (Tregs) normally maintain self-tolerance. Tregs recognize "self" such that when they are not working properly, such as in autoimmunity, the immune system can attack and destroy one's own tissues. Current therapies for autoimmunity rely on relatively ineffective and too often toxic therapies to "treat" the destructive inflammation. Restoring defective endogenous immune regulation (self-tolerance) would represent a paradigm shift in the therapy of these diseases. One recent approach to restore self-tolerance is to use "low dose IL-2" as a therapy to increase the number of circulating Tregs. However, studies to-date have not demonstrated that low-dose IL-2 therapy can restore concomitant Treg function, and phase 2 studies in low dose IL-2 treated patients with autoimmune diseases have failed to demonstrate significant clinical benefit. We hypothesize that the defect in self-tolerance seen in autoimmunity is not due to an insufficient number of available Tregs, but rather, due to defects in second messengers downstream of the IL-2R that normally control Treg function and stability. Previous studies from our lab and others have demonstrated that GRAIL (a ubiquitin E3 ligase) is important in Treg function. GRAIL expression is markedly diminished in Tregs from patients with autoimmune diseases and allergic asthma and is also diminished in Tregs of mice that are considered autoimmune prone. In the relevant pathway in Tregs, GRAIL normally blocks cullin ring ligase activity, which inhibits IL-2R desensitization in Tregs and consequently promotes Treg function. As a result of this defect in GRAIL expression, the Tregs of patients with autoimmune diseases and allergic asthma degrade IL-2R-associated pJAK1 following activation with low dose IL-2, and thus cannot maintain pSTAT5 expression. pSTAT5 controls the transcription of genes required for Treg function. Additionally, the GRAIL-mediated defect may also allow the degradation of the mTOR inhibitor, DEP domain-containing mTOR interacting protein (Deptor). This can lead to IL-2R activation of mTOR and loss of Treg stability in autoimmune patients. Using a monoclonal antibody to the remnant di-glycine tag on ubiquitinated proteins after trypsin digestion, we identified a protein that was ubiquitinated by GRAIL that is important in Treg function, cullin5. Our data demonstrate that GRAIL acts a negative regulator of IL-2R desensitization by ubiquitinating a lysine on cullin5 that must be neddylated to allow cullin5 cullin ring ligase activity. We hypothesize that a neddylation inhibitor in combination with low dose IL-2 activation could be used to substitute for GRAIL and restore Treg function and stability in the Tregs of autoimmune and allergic asthma patients. However, the neddylation activating enzyme inhibitors (NAEi) are toxic when given systemically. By generating a protein drug conjugate (PDC) consisting of a NAEi bound, via cleavable linkers, to a fusion protein of murine IL-2 (to target the drug to Tregs), we were able to use 1000-fold less of the neddylation inhibitor drug than the amount required for therapeutically effective systemic delivery. The PDC was effective in blocking the onset or the progression of disease in several mouse models of autoimmunity (type 1 diabetes, systemic lupus erythematosus, and multiple sclerosis) and a mouse model of allergic asthma in the absence of detectable toxicity. This PDC strategy represents targeted drug delivery at its best where the defect causing the disease was identified, a drug was designed and developed to correct the defect, and the drug was targeted and delivered only to cells that needed it, maximizing safety and efficacy.
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Affiliation(s)
- C. Garrison Fathman
- Department of Medicine, School of Medicine, Stanford University, Palo Alto, CA, United States
| | - Linda Yip
- Department of Medicine, School of Medicine, Stanford University, Palo Alto, CA, United States
| | - Diana Gómez-Martín
- Departamento de Inmunología y Reumatología, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán (INCMNSZ), Mexico City, Mexico
| | - Mang Yu
- Department of Pediatrics, School of Medicine, Stanford University, Palo Alto, CA, United States
| | - Christine M. Seroogy
- Department of Pediatrics, Division of Allergy, Immunology and Rheumatology, University of Wisconsin, Madison, WI, United States
| | | | - Jack T. Lin
- Department of Medicine, School of Medicine, Stanford University, Palo Alto, CA, United States
| | - Jennifer A. Jenks
- Department of Pediatrics, School of Medicine, Stanford University, Palo Alto, CA, United States
| | - Kari C. Nadeau
- Department of Pediatrics, School of Medicine, Stanford University, Palo Alto, CA, United States
- Sean N. Parker Center for Allergy & Asthma Research, School of Medicine, Stanford University, Palo Alto, CA, United States
| | - Luis Soares
- Department of Medicine, School of Medicine, Stanford University, Palo Alto, CA, United States
- IL-2Rx, San Jose, CA, United States
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2
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Zhong T, Lei K, Lin X, Xie Z, Luo S, Zhou Z, Zhao B, Li X. Protein ubiquitination in T cell development. Front Immunol 2022; 13:941962. [PMID: 35990660 PMCID: PMC9386135 DOI: 10.3389/fimmu.2022.941962] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 07/11/2022] [Indexed: 11/26/2022] Open
Abstract
As an important form of posttranslational modification, protein ubiquitination regulates a wide variety of biological processes, including different aspects of T cell development and differentiation. During T cell development, thymic seeding progenitor cells (TSPs) in the thymus undergo multistep maturation programs and checkpoints, which are critical to build a functional and tolerant immune system. Currently, a tremendous amount of research has focused on the transcriptional regulation of thymocyte development. However, in the past few years, compelling evidence has revealed that the ubiquitination system also plays a crucial role in the regulation of thymocyte developmental programs. In this review, we summarize recent findings on the molecular mechanisms and cellular pathways that regulate thymocyte ubiquitination and discuss the roles of E3 ligases and deubiquitinating enzymes (DUBs) involved in these processes. Understanding how T cell development is regulated by ubiquitination and deubiquitination will not only enhance our understanding of cell fate determination via gene regulatory networks but also provide potential novel therapeutic strategies for treating autoimmune diseases and cancer.
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Affiliation(s)
| | | | | | | | | | | | - Bin Zhao
- *Correspondence: Bin Zhao, ; Xia Li,
| | - Xia Li
- *Correspondence: Bin Zhao, ; Xia Li,
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3
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miR-27b-3p Attenuates Muscle Atrophy by Targeting Cbl-b in Skeletal Muscles. Biomolecules 2022; 12:biom12020191. [PMID: 35204692 PMCID: PMC8961554 DOI: 10.3390/biom12020191] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Revised: 01/08/2022] [Accepted: 01/20/2022] [Indexed: 02/04/2023] Open
Abstract
As it is well known, muscle atrophy is a process in which protein degradation increases and protein synthesis decreases. This process is regulated by a variety of links. Among them, microRNAs play an essential role in this process, which has attracted widespread attention. In this paper, we find that miR-27b-3p and Cbl-b genes are significantly differentially expressed in the induced atrophy model. The dual-luciferase experiment and Western blot analysis confirmed that miR-27b-3p could regulate the expression of Cbl-b. In C2C12-differentiated myotubes, the overexpression of the Cbl-b gene showed that Cbl-b could upregulate the expression of MuRF-1 and Atrogin-1, which are related marker genes of muscle atrophy, at both the mRNA and protein levels, indicating that the Cbl-b gene can specifically affect muscle atrophy. The knockdown of the Cbl-b gene after C2C12-differentiated myotubes induced atrophy treatment can downregulate the expression of muscle-atrophy-related genes, indicating that manual intervention to downregulate the expression of Cbl-b has a certain alleviating effect on muscle atrophy. These data suggest that miR-27b-3p can regulate the expression of the Cbl-b gene and then exert a particular influence on muscle atrophy through the Cbl-b gene.
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4
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Zhang Y, Wei Z, Dong H, Zhou J, Yuan J, Ni B, Wu Y, Han C, Tian Y. Regulation of mRNA stability by RBPs and noncoding RNAs contributing to the pathogenicity of Th17 cells. RNA Biol 2020; 18:647-656. [PMID: 33302787 DOI: 10.1080/15476286.2020.1862567] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Th17 cells remain one of the most important subsets of T cells in numerous autoimmune and chronic inflammatory diseases. Posttranscriptional regulation (PTR), especially mRNA stability, has recently emerged as an important mechanism that controls the fate of Th17 cells. This review summarizes the current knowledge on RNA-binding proteins (RBPs), microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) that induce mRNA stability changes and their roles in mediating the differentiation, proliferation, function, and migration of Th17 cells. In addition, we summarize the role of RNA modifications and nonsense-mediated mRNA decay (NMD) in Th17 cells. Ongoing research will help to identify practical applications for the regulation of mRNA stability and provide potential targets to prevent and treat Th17-related autoimmune diseases.
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Affiliation(s)
- Yiwei Zhang
- Institute of Immunology, PLA, Third Military Medical University (Army Medical University), Chongqing, PR China.,Department of Orthopedics, The First Affiliated Hospital of Third Military Medical University (Army Medical University), Chongqing, PR China
| | - Zhiyuan Wei
- Department of Orthopedics, The First Affiliated Hospital of Third Military Medical University (Army Medical University), Chongqing, PR China
| | - Hui Dong
- Institute of Immunology, PLA, Third Military Medical University (Army Medical University), Chongqing, PR China
| | - Jian Zhou
- Institute of Immunology, PLA, Third Military Medical University (Army Medical University), Chongqing, PR China
| | - Jizhao Yuan
- Institute of Immunology, PLA, Third Military Medical University (Army Medical University), Chongqing, PR China
| | - Bing Ni
- Department of Pathophysiology, Third Military Medical University (Army Medical University), Chongqing, PR China
| | - Yuzhang Wu
- Institute of Immunology, PLA, Third Military Medical University (Army Medical University), Chongqing, PR China
| | - Chao Han
- Institute of Immunology, PLA, Third Military Medical University (Army Medical University), Chongqing, PR China
| | - Yi Tian
- Institute of Immunology, PLA, Third Military Medical University (Army Medical University), Chongqing, PR China
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5
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Han S, Toker A, Liu ZQ, Ohashi PS. Turning the Tide Against Regulatory T Cells. Front Oncol 2019; 9:279. [PMID: 31058083 PMCID: PMC6477083 DOI: 10.3389/fonc.2019.00279] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Accepted: 03/26/2019] [Indexed: 12/11/2022] Open
Abstract
Regulatory T (Treg) cells play crucial roles in health and disease through their immunosuppressive properties against various immune cells. In this review we will focus on the inhibitory role of Treg cells in anti-tumor immunity. We outline how Treg cells restrict T cell function based on our understanding of T cell biology, and how we can shift the equilibrium against regulatory T cells. To date, numerous strategies have been proposed to limit the suppressive effects of Treg cells, including Treg cell neutralization, destabilizing Treg cells and rendering T cells resistant to Treg cells. Here, we focus on key mechanisms which render T cells resistant to the suppressive effects of Treg cells. Lastly, we also examine current limitations and caveats of overcoming the inhibitory activity of Treg cells, and briefly discuss the potential to target Treg cell resistance in the context of anti-tumor immunity.
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Affiliation(s)
- SeongJun Han
- Princess Margaret Cancer Centre, Campbell Family Institute for Breast Cancer Research, University Health Network, Toronto, ON, Canada
- Department of Immunology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Aras Toker
- Princess Margaret Cancer Centre, Campbell Family Institute for Breast Cancer Research, University Health Network, Toronto, ON, Canada
| | - Zhe Qi Liu
- Princess Margaret Cancer Centre, Campbell Family Institute for Breast Cancer Research, University Health Network, Toronto, ON, Canada
- Department of Immunology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Pamela S. Ohashi
- Princess Margaret Cancer Centre, Campbell Family Institute for Breast Cancer Research, University Health Network, Toronto, ON, Canada
- Department of Immunology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
- Department of Medical Biophysics, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
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6
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Kleine-Eggebrecht N, Staufner C, Kathemann S, Elgizouli M, Kopajtich R, Prokisch H, Lainka E. Mutation in ITCH Gene Can Cause Syndromic Multisystem Autoimmune Disease With Acute Liver Failure. Pediatrics 2019; 143:peds.2018-1554. [PMID: 30705142 DOI: 10.1542/peds.2018-1554] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 10/08/2018] [Indexed: 11/24/2022] Open
Abstract
Pediatric intractable autoimmune hepatitis is rare and may be responsible for acute liver failure. Mutations in the itchy E3 ubiquitin protein ligase (ITCH) gene (located on chromosome 20q11.22) can lead to a deficiency of the encoded protein, resulting in increased T-cell activity with lack of immune tolerance and manifestation of a complex systemic autoimmune disease. A 1-year-old girl of consanguineous parents received a liver transplant (LT) because of acute liver failure attributed to a drug-induced hypereosinophilic syndrome with positive liver-kidney-mikrosome-2 antibodies. Notable findings were syndromic features, dystrophy, short stature, psychomotor retardation, and muscular hypotonia. Later, we saw corticosteroid-sensitive rejections as well as a systemic autoimmune disease with detection of specific antibodies (de novo autoimmune hepatitis, thyroiditis with exophthalmos, diabetes mellitus type 1, and immune neutropenia). Histologically, liver cirrhosis with lobular inflammatory infiltrates, giant-cell hepatitis, and ductopenia was verified in chronic cholestasis. Shortly after a second LT, a comparable liver histology could be detected, and viral, bacterial, and mycotic infections deteriorated the general health condition. Because of refractory pancytopenia related to portal hypertension and hypersplenism, a posttransplant lymphoproliferative disorder was excluded. One year after the second LT, epidural and subdural bleeding occurred. Three months afterward, the girl died of sepsis. Postmortem, whole-exome sequencing revealed a homozygous mutation in the ITCH gene. A biallelic mutation in ITCH can cause a severe syndromic multisystem autoimmune disease with the above phenotypic characteristics and acute liver failure because of autoimmune hepatitis. This case reveals the importance of ubiquitin pathways for regulation of the immune system.
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Affiliation(s)
| | - Christian Staufner
- Department of Pediatrics, University of Heidelberg, Heidelberg, Germany; and
| | | | | | - Robert Kopajtich
- Institute of Human Genetics, Klinikum rechts der Isar, Technical University Munich, Munich, Germany
| | - Holger Prokisch
- Institute of Human Genetics, Klinikum rechts der Isar, Technical University Munich, Munich, Germany
| | - Elke Lainka
- Departments of Pediatrics, Gastroenterology, and Hepatology and
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7
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Nanjappa SG, Mudalagiriyappa S, Fites JS, Suresh M, Klein BS. CBLB Constrains Inactivated Vaccine-Induced CD8 + T Cell Responses and Immunity against Lethal Fungal Pneumonia. THE JOURNAL OF IMMUNOLOGY 2018; 201:1717-1726. [PMID: 30054317 DOI: 10.4049/jimmunol.1701241] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 07/12/2018] [Indexed: 12/24/2022]
Abstract
Fungal infections in CD4+ T cell immunocompromised patients have risen sharply in recent years. Although vaccines offer a rational avenue to prevent infections, there are no licensed fungal vaccines available. Inactivated vaccines are safer but less efficacious and require adjuvants that may undesirably bias toward poor protective immune responses. We hypothesized that reducing the TCR signaling threshold could potentiate antifungal CD8+ T cell responses and immunity to inactivated vaccine in the absence of CD4+ T cells. In this study, we show that CBLB, a negative regulator of TCR signaling, suppresses CD8+ T cells in response to inactivated fungal vaccination in a mouse model of CD4+ T cell lymphopenia. Conversely, Cblb deficiency enhanced both the type 1 (e.g., IFN-γ) and type 17 (IL-17A) CD8+ T cell responses to inactivated fungal vaccines and augmented vaccine immunity to lethal fungal pneumonia. Furthermore, we show that immunization with live or inactivated vaccine yeast did not cause detectable pathologic condition in Cblb-/- mice. Augmented CD8+ T cell responses in the absence of CBLB also did not lead to terminal differentiation or adversely affect the expression of transcription factors T-bet, Eomes, and RORγt. Additionally, our adoptive transfer experiments showed that CBLB impedes the effector CD8+ T cell responses in a cell-intrinsic manner. Finally, we showed that ablation of Cblb overcomes the requirement of HIF-1α for expansion of CD8+ T cells upon vaccination. Thus, adjuvants that target CBLB may augment inactivated vaccines and immunity against systemic fungal infections in vulnerable patients.
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Affiliation(s)
- Som G Nanjappa
- Department of Pathobiology, University of Illinois at Urbana-Champaign, Urbana, IL 61802;
| | | | - J Scott Fites
- Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, Madison, WI 53792
| | - M Suresh
- Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI 53706
| | - Bruce S Klein
- Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, Madison, WI 53792.,Department of Internal Medicine, University of Wisconsin School of Medicine and Public Health, Madison, WI 53792; and.,Department of Medical Microbiology and Immunology, University of Wisconsin School of Medicine and Public Health, Madison, WI 53792
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8
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Wang S, Xu L, Che X, Li C, Xu L, Hou K, Fan Y, Wen T, Qu X, Liu Y. E3 ubiquitin ligases Cbl-b and c-Cbl downregulate PD-L1 in EGFR wild-type non-small cell lung cancer. FEBS Lett 2018; 592:621-630. [PMID: 29364514 DOI: 10.1002/1873-3468.12985] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Revised: 12/14/2017] [Accepted: 01/17/2018] [Indexed: 01/12/2023]
Abstract
Anti-PD-1/PD-L1 therapies have demonstrated prominent clinical effects in the treatment of non-small cell lung cancer (NSCLC). However, limited understanding of the regulatory mechanisms of PD-L1 has become one of the biggest challenges for further improving efficacy. In this study, we observed that in wild-type EFGR cell lines A549 and H460, the ubiquitin ligases Cbl-b and c-Cbl inhibit PD-L1 by inactivating STAT, AKT, and ERK signaling. MiR-181a and miR-940 were screened and validated to target Cbl-b and c-Cbl, respectively. Furthermore, in NSCLC tissues, the expression of Cbl-b/c-Cbl is negatively correlated with PD-L1 expression. Taken together, these findings indicated a new regulatory mechanism for PD-L1 in wild-type EGFR NSCLC cell lines by Cbl-b and c-Cbl.
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Affiliation(s)
- Shuo Wang
- Department of Medical Oncology, the First Hospital of China Medical University, Shenyang, China.,Key Laboratory of Anticancer Drugs and Biotherapy of Liaoning Province, Department of Medical Oncology, the First Hospital of China Medical University, Shenyang, China
| | - Ling Xu
- Department of Medical Oncology, the First Hospital of China Medical University, Shenyang, China.,Key Laboratory of Anticancer Drugs and Biotherapy of Liaoning Province, Department of Medical Oncology, the First Hospital of China Medical University, Shenyang, China
| | - Xiaofang Che
- Department of Medical Oncology, the First Hospital of China Medical University, Shenyang, China.,Key Laboratory of Anticancer Drugs and Biotherapy of Liaoning Province, Department of Medical Oncology, the First Hospital of China Medical University, Shenyang, China
| | - Ce Li
- Department of Medical Oncology, the First Hospital of China Medical University, Shenyang, China.,Key Laboratory of Anticancer Drugs and Biotherapy of Liaoning Province, Department of Medical Oncology, the First Hospital of China Medical University, Shenyang, China
| | - Lu Xu
- Department of Medical Oncology, the First Hospital of China Medical University, Shenyang, China.,Key Laboratory of Anticancer Drugs and Biotherapy of Liaoning Province, Department of Medical Oncology, the First Hospital of China Medical University, Shenyang, China
| | - Kezuo Hou
- Department of Medical Oncology, the First Hospital of China Medical University, Shenyang, China.,Key Laboratory of Anticancer Drugs and Biotherapy of Liaoning Province, Department of Medical Oncology, the First Hospital of China Medical University, Shenyang, China
| | - Yibo Fan
- Department of Medical Oncology, the First Hospital of China Medical University, Shenyang, China.,Key Laboratory of Anticancer Drugs and Biotherapy of Liaoning Province, Department of Medical Oncology, the First Hospital of China Medical University, Shenyang, China
| | - Ti Wen
- Department of Medical Oncology, the First Hospital of China Medical University, Shenyang, China.,Key Laboratory of Anticancer Drugs and Biotherapy of Liaoning Province, Department of Medical Oncology, the First Hospital of China Medical University, Shenyang, China
| | - Xiujuan Qu
- Department of Medical Oncology, the First Hospital of China Medical University, Shenyang, China.,Key Laboratory of Anticancer Drugs and Biotherapy of Liaoning Province, Department of Medical Oncology, the First Hospital of China Medical University, Shenyang, China
| | - Yunpeng Liu
- Department of Medical Oncology, the First Hospital of China Medical University, Shenyang, China.,Key Laboratory of Anticancer Drugs and Biotherapy of Liaoning Province, Department of Medical Oncology, the First Hospital of China Medical University, Shenyang, China
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9
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Morris G, Barichello T, Stubbs B, Köhler CA, Carvalho AF, Maes M. Zika Virus as an Emerging Neuropathogen: Mechanisms of Neurovirulence and Neuro-Immune Interactions. Mol Neurobiol 2017; 55:4160-4184. [PMID: 28601976 DOI: 10.1007/s12035-017-0635-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Accepted: 05/23/2017] [Indexed: 01/08/2023]
Abstract
Zika virus (ZIKV) is an emerging arbovirus of the genus Flaviviridae, which causes a febrile illness and has spread from across the Pacific to the Americas in a short timeframe. Convincing evidence has implicated the ZIKV to incident cases of neonatal microcephaly and a set of neurodevelopmental abnormalities referred to as the congenital Zika virus syndrome. In addition, emerging data points to an association with the ZIKV and the development of the so-called Guillain-Barre syndrome, an acute autoimmune polyneuropathy. Accumulating knowledge suggests that neurovirulent strains of the ZIKV have evolved from less pathogenic lineages of the virus. Nevertheless, mechanisms of neurovirulence and host-pathogen neuro-immune interactions remain incompletely elucidated. This review provides a critical discussion of genetic and structural alterations in the ZIKV which could have contributed to the emergence of neurovirulent strains. In addition, a mechanistic framework of neuro-immune mechanisms related to the emergence of neuropathology after ZIKV infection is discussed. Recent advances in knowledge point to avenues for the development of a putative vaccine as well as novel therapeutic strategies. Nevertheless, there are unique unmet challenges that need to be addressed in this regard. Finally, a research agenda is proposed.
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Affiliation(s)
- Gerwyn Morris
- Tir Na Nog, Bryn Road seaside 87, Llanelli, Wales, SA15 2LW, UK
| | - Tatiana Barichello
- Laboratory of Experimental Microbiology, Graduate Program in Health Sciences, Health Sciences Unit, University of Southern Santa Catarina (UNESC), Criciúma, SC, Brazil.,Translational Psychiatry Program, Department of Psychiatry and Behavioral Sciences, McGovern Medical School, The University of Texas Health Science Center at Houston (UTHealth), Houston, TX, USA.,Neuroscience Graduate Program, The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, TX, USA
| | - Brendon Stubbs
- Physiotherapy Department, South London and Maudsley NHS Foundation Trust, Denmark Hill, London, SE5 8AZ, UK.,Health Service and Population Research Department, Institute of Psychiatry, Psychology and Neuroscience, King's College London, De Crespigny Park, London, SE5 8AF, UK.,Faculty of Health, Social Care and Education, Anglia Ruskin University, Bishop Hall Lane, Chelmsford, CM1 1SQ, UK
| | - Cristiano A Köhler
- Department of Clinical Medicine and Translational Psychiatry Research Group, Faculty of Medicine, Federal University of Ceará, Fortaleza, CE, Brazil
| | - André F Carvalho
- Department of Clinical Medicine and Translational Psychiatry Research Group, Faculty of Medicine, Federal University of Ceará, Fortaleza, CE, Brazil
| | - Michael Maes
- IMPACT Strategic Research Centre, School of Medicine, Barwon Health, Deakin University, P.O. Box 291, Geelong, VIC, 3220, Australia. .,Health Sciences Postgraduate Program, Health Sciences Center, State University of Londrina, Londrina, Parana, Brazil. .,Department of Psychiatry, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand. .,Revitalis, Waalre, The Netherlands. .,Department of Psychiatry, Medical University of Plovdiv, Plovdiv, Bulgaria.
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10
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Huang XL, Zhang L, Duan Y, Wang YJ, Zhao JH, Wang J. E3 ubiquitin ligase: A potential regulator in fibrosis and systemic sclerosis. Cell Immunol 2016; 306-307:1-8. [PMID: 27406900 DOI: 10.1016/j.cellimm.2016.07.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2016] [Revised: 05/17/2016] [Accepted: 07/05/2016] [Indexed: 01/11/2023]
Abstract
Systemic sclerosis (SSc) is an autoimmune disease characterized by fibrosis in the skin and internal organs. The pathogenesis of SSc is not completely understood until now. Recently, many studies have focused on the role of E3 ubiquitin ligases in organ fibrosis. However, the possible regulatory mechanisms of E3 ubiquitin ligases in fibrosis and SSc are not well documented. In this review, we summarized that E3 ubiquitin ligases regulated fibrosis through ubiquitin-mediated degradation of TGF-β/Smad signaling pathway. Moreover, E3 ubiquitin ligases participated in regulating fibrosis by other methods, such as inducing epithelial transition to mesenchymal cell, enhancing the production of TGF-β and protecting activated hepatic stellate cells from apoptosis. However, the specific regulatory mechanisms of E3 ubiquitin ligases in scleroderma is still not fully understood. There are more works to be done to specify the mechanism of E3 ubiquitin ligases in regulation of fibrosis in SSc.
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Affiliation(s)
- Xiao-Lei Huang
- Department of Epidemiology and Biostatistics, School of Public Health, Anhui Medical University, Hefei, China
| | - Li Zhang
- Medical Genetics Center, Anhui Medical College, Hefei, China
| | - Yu Duan
- Department of Epidemiology and Biostatistics, School of Public Health, Anhui Medical University, Hefei, China
| | - Yu-Jie Wang
- Department of Epidemiology and Biostatistics, School of Public Health, Anhui Medical University, Hefei, China
| | - Jiu-Hua Zhao
- West Anhui Health Vocational College, Lu'an, Anhui, China
| | - Jing Wang
- Department of Epidemiology and Biostatistics, School of Public Health, Anhui Medical University, Hefei, China.
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11
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Athanasopoulos V, Ramiscal RR, Vinuesa CG. ROQUIN signalling pathways in innate and adaptive immunity. Eur J Immunol 2016; 46:1082-90. [PMID: 27060455 DOI: 10.1002/eji.201545956] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Revised: 03/15/2016] [Accepted: 03/30/2016] [Indexed: 12/25/2022]
Abstract
ROQUIN is an RNA-binding protein that plays important roles in both the innate and adaptive immune systems. ROQUIN binds to several key immune-relevant messenger RNA (mRNA) targets through its ROQ domain modulating their stability and influencing macrophage function and the peripheral homeostasis of T cells and B cells. More recently, the E3 ubiquitin ligase activity of the ROQUIN RING domain has been shown to be crucial for T-cell-dependent B-cell responses against infection. Defective ROQUIN activity can culminate in a range of diseases, such as systemic autoimmunity, immunodeficiency, and inflammatory bowel disorder. Here, we provide a current overview of the immunomodulatory role of ROQUIN defined by its ribonucleoprotein-like structure, its repertoire of mRNA targets shared by related RNA-binding enzymes, and its involvement in a range of intracellular signalling pathways central to shaping immune responses.
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Affiliation(s)
- Vicki Athanasopoulos
- John Curtin School of Medical Research, Australian National University, Canberra, Australia
| | - Roybel R Ramiscal
- John Curtin School of Medical Research, Australian National University, Canberra, Australia
| | - Carola G Vinuesa
- John Curtin School of Medical Research, Australian National University, Canberra, Australia
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12
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Herrington FD, Carmody RJ, Goodyear CS. Modulation of NF-κB Signaling as a Therapeutic Target in Autoimmunity. ACTA ACUST UNITED AC 2015; 21:223-42. [PMID: 26597958 DOI: 10.1177/1087057115617456] [Citation(s) in RCA: 100] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 10/26/2015] [Indexed: 01/04/2023]
Abstract
Autoimmune diseases arise from the loss of tolerance to endogenous self-antigens, resulting in a heterogeneous range of chronic conditions that cause considerable morbidity and mortality worldwide. In Western countries, over 5% of the population is affected by some form of autoimmune disease, with enhanced or inappropriate activation of nuclear factor (NF)-κB implicated in a number of these conditions. Although treatment strategies for autoimmunity have improved significantly in recent years, current therapeutics are still not capable of achieving satisfactory disease management in all patients, and as such, the therapeutic modulation of NF-κB is an attractive target in autoimmunity. To date, no NF-κB inhibitors have progressed to the clinic for the treatment of autoimmunity, but a variety of promising approaches targeting multiple stages of the NF-κB pathway are currently being explored. This review focuses on the current strategies being investigated for the inhibition of the NF-κB pathway in autoimmune diseases and considers potential future strategies for the therapeutic targeting of this crucial transcription factor.
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Affiliation(s)
- Felicity D Herrington
- University of Glasgow, Institute of Infection, Immunity and Inflammation, Glasgow, UK
| | - Ruaidhrí J Carmody
- University of Glasgow, Institute of Infection, Immunity and Inflammation, Glasgow, UK
| | - Carl S Goodyear
- University of Glasgow, Institute of Infection, Immunity and Inflammation, Glasgow, UK GLAZgo Discovery Centre, University of Glasgow, Institute of Infection, Immunity and Inflammation, Glasgow, UK
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13
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Natural small molecule FMHM inhibits lipopolysaccharide-induced inflammatory response by promoting TRAF6 degradation via K48-linked polyubiquitination. Sci Rep 2015; 5:14715. [PMID: 26423026 PMCID: PMC4589686 DOI: 10.1038/srep14715] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Accepted: 09/01/2015] [Indexed: 12/11/2022] Open
Abstract
TNF receptor-associated factor 6 (TRAF6) is a key hub protein involved in Toll-like receptor-dependent inflammatory signaling pathway, and it recruits additional proteins to form multiprotein complexes capable of activating downstream NF-κB inflammatory signaling pathway. Ubiquitin-proteasome system (UPS) plays a crucial role in various protein degradations, such as TRAF6, leading to inhibitory effects on inflammatory response and immunologic function. However, whether ubiquitination-dependent TRAF6 degradation can be used as a novel anti-inflammatory drug target still remains to be explored. FMHM, a bioactive natural small molecule compound extracted from Chinese herbal medicine Radix Polygalae, suppressed acute inflammatory response by targeting ubiquitin protein and inducing UPS-dependent TRAF6 degradation mechanism. It was found that FMHM targeted ubiquitin protein via Lys48 site directly induced Lys48 residue-linked polyubiquitination. This promoted Lys48 residue-linked polyubiquitin chain formation on TRAF6, resulting in increased TRAF6 degradation via UPS and inactivation of downstream NF-κB inflammatory pathway. Consequently, FMHM down-regulated inflammatory mediator levels in circulation, protected multiple organs against inflammatory injury in vivo, and prolong the survival of endotoxemia mouse models. Therefore, FMHM can serve as a novel lead compound for the development of TRAF6 scavenging agent via ubiquitination-dependent mode, which represents a promising strategy for treating inflammatory diseases.
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14
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K33-linked polyubiquitination of Zap70 by Nrdp1 controls CD8(+) T cell activation. Nat Immunol 2015; 16:1253-62. [PMID: 26390156 DOI: 10.1038/ni.3258] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Accepted: 07/30/2015] [Indexed: 12/11/2022]
Abstract
The key molecular mechanisms that control signaling via T cell antigen receptors (TCRs) remain to be fully elucidated. Here we found that Nrdp1, a ring finger-type E3 ligase, mediated Lys33 (K33)-linked polyubiquitination of the signaling kinase Zap70 and promoted the dephosphorylation of Zap70 by the acidic phosphatase-like proteins Sts1 and Sts2 and thereby terminated early TCR signaling in CD8(+) T cells. Nrdp1 deficiency significantly promoted the activation of naive CD8(+) T cells but not that of naive CD4(+) T cells after engagement of the TCR. Nrdp1 interacted with Zap70 and with Sts1 and Sts2 and connected K33 linkage of Zap70 to Sts1- and Sts2-mediated dephosphorylation. Our study suggests that Nrdp1 terminates early TCR signaling by inactivating Zap70 and provides new mechanistic insights into the non-proteolytic regulation of TCR signaling by E3 ligases.
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15
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Lutz-Nicoladoni C, Wolf D, Sopper S. Modulation of Immune Cell Functions by the E3 Ligase Cbl-b. Front Oncol 2015; 5:58. [PMID: 25815272 PMCID: PMC4356231 DOI: 10.3389/fonc.2015.00058] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Accepted: 02/24/2015] [Indexed: 01/10/2023] Open
Abstract
Maintenance of immunological tolerance is a critical hallmark of the immune system. Several signaling checkpoints necessary to balance activating and inhibitory input to immune cells have been described so far, among which the E3 ligase Cbl-b appears to be a central player. Cbl-b is expressed in all leukocyte subsets and regulates several signaling pathways in T cells, NK cells, B cells, and different types of myeloid cells. In most cases, Cbl-b negatively regulates activation signals through antigen or pattern recognition receptors and co-stimulatory molecules. In line with this function, cblb-deficient immune cells display lower activation thresholds and cblb knockout mice spontaneously develop autoimmunity and are highly susceptible to experimental autoimmunity. Interestingly, genetic association studies link CBLB-polymorphisms with autoimmunity also in humans. Vice versa, the increased activation potential of cblb-deficient cells renders them more potent to fight against malignancies or infections. Accordingly, several reports have shown that cblb knockout mice reject tumors, which mainly depends on cytotoxic T and NK cells. Thus, targeting Cbl-b may be an interesting strategy to enhance anti-cancer immunity. In this review, we summarize the findings on the molecular function of Cbl-b in different cell types and illustrate the potential of Cbl-b as target for immunomodulatory therapies.
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Affiliation(s)
- Christina Lutz-Nicoladoni
- Department of Hematology and Oncology, Medical University Innsbruck , Innsbruck , Austria ; Tumor Immunology Laboratory, Tyrolean Cancer Research Institute , Innsbruck , Austria
| | - Dominik Wolf
- Medical Clinic III for Oncology, Haematology and Rheumatology, University Clinic Bonn (UKB) , Bonn , Germany
| | - Sieghart Sopper
- Department of Hematology and Oncology, Medical University Innsbruck , Innsbruck , Austria ; Tumor Immunology Laboratory, Tyrolean Cancer Research Institute , Innsbruck , Austria
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16
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Bu N, Wu H, Zhang G, Zhan S, Zhang R, Sun H, Du Y, Yao L, Wang H. Exosomes from Dendritic Cells Loaded with Chaperone-Rich Cell Lysates Elicit a Potent T Cell Immune Response Against Intracranial Glioma in Mice. J Mol Neurosci 2015; 56:631-43. [PMID: 25680514 DOI: 10.1007/s12031-015-0506-9] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Accepted: 01/29/2015] [Indexed: 01/05/2023]
Abstract
Chaperone-rich cell lysates (CRCLs) may play an important role in the development of anti-tumor vaccines. Tumor-derived CRCLs have been reported to activate dendritic cells (DCs) to elicit potent anti-tumor activity. However, the role of DC-derived exosomes (DEXs) secreted from DCs loaded with CRCLs in the treatment of tumors has not been clearly determined. In the present study, DEXs were generated from DCs loaded with CRCLs derived from GL261 glioma cells. These DEXs, designated DEX (CRCL-GL261), were then used to treat DCs to create DEX (CRCL-GL261)-DCs. The DEX (CRCL-GL261)-DCs were found to promote cell proliferation and cytotoxic T lymphocyte (CTL) activity of CD4(+) and CD8(+) T cells in vitro compared with DEX (GL261)-DCs, which were loaded with DEXs derived from DCs loaded with GL261 tumor cell lysates. DEX (CRCL-GL261)-DCs significantly prolonged the survival of mice with tumors and inhibited tumor growth in vivo. In addition, DEX (CRCL-GL261)-DCs induced enhanced T cell infiltration in intracranial glioma tissues compared with other treatments. DEX (CRCL-GL261)-DCs induced strong production of anti-tumor cytokines, including interleukin-2 and interferon-γ. Moreover, depletion of CD4(+) and CD8(+) T cells significantly impaired the anti-tumor effect of DEX (CRCL-GL261)-DCs. Finally, DEX (CRCL-GL261)-DCs were found to negatively regulate Casitas B cell lineage lymphoma (Cbl)-b and c-Cbl signaling, leading to the activation of phosphatidyl inositol 3-kinase (PI3K)/Akt and extracellular signal-regulated kinase (ERK) signaling in T cells. In summary, we present evidence that DEX (CRCL-GL261)-DCs induce more potent and effective anti-tumor T cell immune responses and delineate the underlying mechanism by which DEX (CRCL-GL261)-DCs exerted their anti-tumor activity through modulating Cbl-b and c-Cbl signaling. These results provide novel and promising insight for the development of an anti-tumor vaccine.
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Affiliation(s)
- Ning Bu
- Department of Neurology, The Second Affiliated Hospital, Xi'an Jiaotong University, No. 157 Xiwu Road, Xi'an, 710004, Shaanxi, People's Republic of China,
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17
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Schaefer JS, Montufar-Solis D, Klein JR. A role for IL-10 in the transcriptional regulation of Roquin-1. Gene 2014; 549:134-40. [PMID: 25062971 DOI: 10.1016/j.gene.2014.07.056] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Revised: 07/03/2014] [Accepted: 07/21/2014] [Indexed: 01/25/2023]
Abstract
Roquin-1, a RING finger E3 ubiquitin ligase, functions as a modulator of inflammation; however, nothing is known about how Rc3h1 expression is regulated. Here, we describe an opposing relationship between Roquin-1 and the IL-17 proinflammatory cytokine by demonstrating that enforced expression of Rc3h1 restricts Il17a expression, and that exposure of T cells to IL-10, a cytokine with immunosuppressive activity, increases Rc3h1 expression. Luciferase reporter assays conducted using eight transcription factor plasmids (STAT1, STAT3, STAT5, GATA2, c-Rel, IKZF1, IKZF2, and IKZF3) demonstrated that STAT1, STAT3, GATA2, and c-Rel increased Rc3h1 promoter activity, whereas IKZF2 decreased activity. Gene expression of those five transcription factors increased in T cells exposed to IL-10. Transcription factor-specific siRNAs suppressed the IL-10 effect on Rc3h1 transcription. These findings identify a role for IL-10 in regulating Rc3h1 transcription, and they have implications for understanding how Roquin-1 controls the immune response.
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Affiliation(s)
- Jeremy S Schaefer
- Department of Diagnostic and Biomedical Sciences, School of Dentistry, The University of Texas Health Science Center at Houston, Houston, TX 77054, USA
| | - Dina Montufar-Solis
- Department of Diagnostic and Biomedical Sciences, School of Dentistry, The University of Texas Health Science Center at Houston, Houston, TX 77054, USA
| | - John R Klein
- Department of Diagnostic and Biomedical Sciences, School of Dentistry, The University of Texas Health Science Center at Houston, Houston, TX 77054, USA.
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18
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Weil R. Does antigen masking by ubiquitin chains protect from the development of autoimmune diseases? Front Immunol 2014; 5:262. [PMID: 24917867 PMCID: PMC4042494 DOI: 10.3389/fimmu.2014.00262] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Accepted: 05/19/2014] [Indexed: 11/20/2022] Open
Abstract
Autoimmune diseases are characterized by the production of antibodies against self-antigens and generally arise from a failure of central or peripheral tolerance. However, these diseases may develop when newly appearing antigens are not recognized as self by the immune system. The mechanism by which some antigens are “invisible” to the immune system is not completely understood. Apoptotic and complement system defects or autophagy imbalance can generate this antigenic autoreactivity. Under particular circumstances, cellular debris containing autoreactive antigens can be recognized by innate immune receptors or other sensors and can eventually lead to autoimmunity. Ubiquitination may be one of the mechanisms protecting autoreactive antigens from the immune system that, if disrupted, can lead to autoimmunity. Ubiquitination is an essential post-translational modification used by cells to target proteins for degradation or to regulate other intracellular processes. The level of ubiquitination is regulated during T cell tolerance and apoptosis and E3 ligases have emerged as a crucial signaling pathway for the regulation of T cell tolerance toward self-antigens. I propose here that an unrecognized role of ubiquitin and ubiquitin-like proteins could be to render intracellular or foreign antigens (present in cellular debris resulting from apoptosis, complement system, or autophagy defects) invisible to the immune system in order to prevent the development of autoimmunity.
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Affiliation(s)
- Robert Weil
- Unité de Signalisation Moléculaire et Activation Cellulaire, CNRS URA 2582, Institut Pasteur , Paris , France
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19
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Montufar-Solis D, Vigneswaran N, Nakra N, Schaefer JS, Klein JR. Hematopoietic not systemic impairment of Roquin expression accounts for intestinal inflammation in Roquin-deficient mice. Sci Rep 2014; 4:4920. [PMID: 24815331 PMCID: PMC4017215 DOI: 10.1038/srep04920] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Accepted: 04/22/2014] [Indexed: 01/17/2023] Open
Abstract
Roquin, an E3 ligase, is involved in curtailing autoimmune pathology as seen from studies using mice with mutated (Rc3h1san/san) or disrupted (Rc3h1gt/gt) Rc3h1 gene. The extent to which intestinal immunopathology is caused by insufficient Roquin expression in the immune system, or by Roquin impairment in non-hematopoietic cells, has not been determined. Using bone marrow cells from Rc3h1gt/gt mice transferred into irradiated normal mice (Rc3h1gt/gt → NL chimeras), we show that inflammation developed in the small intestine, kidney, lung, liver, and spleen. Proinflammatory cytokine levels were elevated in lamina propria lymphocytes (LPLs). Inflammation in the liver was accompanied by areas of hepatocyte apoptosis. Lung inflammation consisted of an influx of both T cells and B cells. Small intestinal LPLs had increased numbers of CD44hi, CD62Llo, KLRG1+, ICOS+ short-lived effector cells, indicating an influx of activated T cells. Following oral infection with L. monocytogenes, Rc3h1gt/gt → NL chimeras had more liver pathology and greater numbers of bacteria in the Peyer's patches than NL → NL chimeras. These findings demonstrate that small intestinal inflammation in Rc3h1san/san and Rc3h1gt/gt mice is due to a failure of Roquin expression in the immune system and not to insufficient systemic Roquin expression.
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Affiliation(s)
- Dina Montufar-Solis
- Department of Diagnostic and Biomedical Sciences, School of Dentistry, The University of Texas Health Science Center at Houston, Houston, TX 77054 USA
| | - Nadarajah Vigneswaran
- Department of Diagnostic and Biomedical Sciences, School of Dentistry, The University of Texas Health Science Center at Houston, Houston, TX 77054 USA
| | - Niyati Nakra
- Department of Diagnostic and Biomedical Sciences, School of Dentistry, The University of Texas Health Science Center at Houston, Houston, TX 77054 USA
| | - Jeremy S Schaefer
- Department of Diagnostic and Biomedical Sciences, School of Dentistry, The University of Texas Health Science Center at Houston, Houston, TX 77054 USA
| | - John R Klein
- Department of Diagnostic and Biomedical Sciences, School of Dentistry, The University of Texas Health Science Center at Houston, Houston, TX 77054 USA
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20
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Abstract
T cell activation is a key event in the adaptive immune response and vital to the generation of both cellular and humoral immunity. Activation is required not only for effective CD4 T cell responses but also to provide help for B cells and the generation of cytotoxic T cell responses. Unsurprisingly, impaired T cell activation results in infectious pathology, whereas dysregulated activation can result in autoimmunity. The decision to activate is therefore tightly regulated and the CD28/CTLA-4 pathway represents this apical decision point at the molecular level. In particular, CTLA-4 (CD152) is an essential checkpoint control for autoimmunity; however, the molecular mechanism(s) by which CTLA-4 achieves its regulatory function are not well understood, especially how it functionally intersects with the CD28 pathway. In this chapter, we review the established molecular and cellular concepts relating to CD28 and CTLA-4 biology, and attempt to integrate these by discussing the transendocytosis of ligands as a new model of CTLA-4 function.
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Affiliation(s)
- Blagoje Soskic
- School of Immunity and Infection, University of Birmingham, Birmingham, United Kingdom
| | | | - Tiezheng Hou
- UCL Institute of Immunity and Transplantation, Royal Free Campus, London, United Kingdom
| | - David M Sansom
- UCL Institute of Immunity and Transplantation, Royal Free Campus, London, United Kingdom.
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21
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Abstract
Ubiquitination is a post-translational modification process that has been implicated in the regulation of innate and adaptive immune responses. There is increasing evidence that both ubiquitination and its reversal, deubiquitination, play crucial roles not only during the development of the immune system but also in the orchestration of an immune response by ensuring the proper functioning of the different cell types that constitute the immune system. Here, we provide an overview of the latest discoveries in this field and discuss how they impact our understanding of the ubiquitin system in host defence mechanisms as well as self-tolerance.
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Affiliation(s)
- Julia Zinngrebe
- Centre for Cell Death, Cancer, and Inflammation (CCCI) UCL Cancer Institute, University College London, London, UK
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22
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Xie JJ, Liang JQ, Diao LH, Altman A, Li Y. TNFR-associated factor 6 regulates TCR signaling via interaction with and modification of LAT adapter. THE JOURNAL OF IMMUNOLOGY 2013; 190:4027-36. [PMID: 23514740 DOI: 10.4049/jimmunol.1202742] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
TNFR-associated factor (TRAF)6 is an essential ubiquitin E3 ligase in immune responses, but its function in adaptive immunity is not well understood. In this study, we show that TRAF6 is recruited to the peripheral ring of the T cell immunological synapse in Jurkat T cells or human primary CD4(+) T cells conjugated with staphylococcal enterotoxin E-pulsed B cells. This recruitment depends on TRAF6 interacting with linker for activation of T cells (LAT) via its TRAF domain. Although LAT was indispensable for TCR/CD28-induced TRAF6 ubiquitination and its ligase activity, RNA interference-induced TRAF6 knockdown in T cells decreased TCR/CD28-induced LAT ubiquitination, tyrosine phosphorylation, and association with tyrosine kinase ZAP70. Overexpression of TRAF6 or its catalytically inactive form C70A promoted and decreased, respectively, LAT tyrosine phosphorylation upon stimulation. Moreover, LAT was ubiquitinated at Lys(88) by TRAF6 via K63-linked chain. In addition, TRAF6 was required for and synergized with LAT to promote the TCR/CD28-induced activation of NFAT. These results reveal a novel function and mechanism of TRAF6 action in the TCR-LAT signaling pathway distinct from its role in TCR-induced NF-κB activation, indicating that LAT also plays an adapter role in TCR/CD28-induced activation of TRAF6.
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Affiliation(s)
- Ji-Ji Xie
- State Key Laboratory of Biocontrol, Key Laboratory of Gene Engineering of Ministry of Education, School of Life Sciences, Sun Yat-sen University, Guangzhou 510006, China
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23
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Schaefer JS, Montufar-Solis D, Nakra N, Vigneswaran N, Klein JR. Small intestine inflammation in Roquin-mutant and Roquin-deficient mice. PLoS One 2013; 8:e56436. [PMID: 23451046 PMCID: PMC3581552 DOI: 10.1371/journal.pone.0056436] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2012] [Accepted: 01/10/2013] [Indexed: 01/05/2023] Open
Abstract
Roquin, an E3 ubiquitin ligase that localizes to cytosolic RNA granules, is involved in regulating mRNA stability and translation. Mice that have a M199R mutation in the Roquin protein (referred to as sanroque or Roquinsan/san mice) develop autoimmune pathologies, although the extent to which these occur in the intestinal mucosa has not been determined. Here, we demonstrate that Roquinsan/san mice reproducibly develop intestinal inflammation in the small intestine but not the colon. Similarly, mice generated in our laboratory in which the Roquin gene was disrupted by insertion of a gene trap cassette (Roquingt/gt mice) had small intestinal inflammation that mimicked that of Roquinsan/san mice. MLN cells in Roquinsan/san mice consisted of activated proliferating T cells, and had increased numbers of CD44hi CD62Llo KLRG1+ short-lived effector cells. Proportionally more small intestinal intraepithelial lymphocytes in Roquinsan/san mice expressed the ICOS T cell activation marker. Of particular interest, small intestinal lamina propria lymphocytes in Roquinsan/san mice consisted of a high proportion of Gr-1+ T cells that included IL-17A+ cells and CD8+ IFN-γ+ cells. Extensive cytokine dysregulation resulting in both over-expression and under-expression of chemotactic cytokines occurred in the ileum of Roquinsan/san mice, the region most prone to the development of inflammation. These findings demonstrate that chronic inflammation ensues in the intestine following Roquin alteration either as a consequence of protein mutation or gene disruption, and they have implications for understanding how small intestinal inflammation is perpetuated in Crohn's disease (CD). Due to the paucity of animal models of CD-like pathophysiology in the small intestine, and because the primary gene/protein defects of the Roquin animal systems used here are well-defined, it will be possible to further elucidate the underlying genetic and molecular mechanisms that drive the disease process.
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Affiliation(s)
- Jeremy S. Schaefer
- Department of Diagnostic and Biomedical Sciences, University of Texas Health Science Center School of Dentistry, Houston, Texas, United States of America
| | - Dina Montufar-Solis
- Department of Diagnostic and Biomedical Sciences, University of Texas Health Science Center School of Dentistry, Houston, Texas, United States of America
| | - Niyati Nakra
- Department of Diagnostic and Biomedical Sciences, University of Texas Health Science Center School of Dentistry, Houston, Texas, United States of America
| | - Nadarajah Vigneswaran
- Department of Diagnostic and Biomedical Sciences, University of Texas Health Science Center School of Dentistry, Houston, Texas, United States of America
| | - John R. Klein
- Department of Diagnostic and Biomedical Sciences, University of Texas Health Science Center School of Dentistry, Houston, Texas, United States of America
- * E-mail:
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24
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Chuang WY, Kung PH, Kuo CY, Wu CC. Sulforaphane prevents human platelet aggregation through inhibiting the phosphatidylinositol 3-kinase/Akt pathway. Thromb Haemost 2013; 109:1120-30. [PMID: 23426129 DOI: 10.1160/th12-09-0636] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2012] [Accepted: 01/23/2013] [Indexed: 01/05/2023]
Abstract
Sulforaphane, a dietary isothiocyanate found in cruciferous vegetables, has been shown to exert beneficial effects in animal models of cardiovascular diseases. However, its effect on platelet aggregation, which is a critical factor in arterial thrombosis, is still unclear. In the present study, we show that sulforaphane inhibited human platelet aggregation caused by different receptor agonists, including collagen, U46619 (a thromboxane A2 mimic), protease-activated receptor 1 agonist peptide (PAR1-AP), and an ADP P2Y12 receptor agonist. Moreover, sulforaphane significantly reduced thrombus formation on a collagen-coated surface under whole blood flow conditions. In exploring the underlying mechanism, we found that sulforaphane specifically prevented phosphatidylinositol 3-kinase (PI3K)/Akt signalling, without markedly affecting other signlaling pathways involved in platelet aggregation, such as protein kinase C activation, calcium mobilisation, and protein tyrosine phosphorylation. Although sulforaphane did not directly inhibit the catalytic activity of PI3K, it caused ubiquitination of the regulatory p85 subunit of PI3K, and prevented PI3K translocation to membranes. In addition, sulforaphane caused ubiquitination and degradation of phosphoinositide-dependent kinase 1 (PDK1), which is required for Akt activation. Therefore, sulforaphane is able to inhibit the PI3K/Akt pathway at two distinct sites. In conclusion, we have demonstrated that sulforaphane prevented platelet aggregation and reduced thrombus formation in flow conditions; our data also support that the inhibition of the PI3K/Akt pathway by sulforaphane contributes it antiplatelet effects.
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Affiliation(s)
- Wen-Ying Chuang
- Graduate Institute of Natural Products, Kaohsiung Medical University, Kaohsiung, Taiwan
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25
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Gorentla BK, Zhong XP. T cell Receptor Signal Transduction in T lymphocytes. JOURNAL OF CLINICAL & CELLULAR IMMUNOLOGY 2012; 2012:5. [PMID: 23946894 PMCID: PMC3740441 DOI: 10.4172/2155-9899.s12-005] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The T cell receptor (TCR) recognizes self or foreign antigens presented by major histocompatibility complex (MHC) molecules. Engagement of the TCR triggers the formation of multi-molecular signalosomes that lead to the generation of second messengers and subsequent activation of multiple distal signaling cascades, such as the Ca+2-calcineurin-NFAT, RasGRP1-Ras-Erk1/2, PKCθ-IKK-NFκB, and TSC1/2-mTOR pathways. These signaling cascades control many aspects of T cell biology. Mechanisms have been evolved to fine-tune TCR signaling to maintain T cell homeostasis and self-tolerance, and to properly mount effective responses to microbial infection. Defects or deregulation of TCR signaling has been implicated in the pathogenesis of multiple human diseases.
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Affiliation(s)
- Balachandra K Gorentla
- Pediatric Biology Center, Translational Health Science and Technology Institute, Gurgaon, 122016, India
| | - Xiao-Ping Zhong
- Department of Pediatrics, Duke University Medical Center, Durham, NC 27710, USA
- Department of Immunology, Duke University Medical Center, Durham, NC 27710, USA
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26
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Ji YR, Kim HJ, Yu DH, Bae KB, Park SJ, Yi JK, Kim N, Park SJ, Oh KB, Hwang SS, Lee S, Kim SH, Kim MO, Lee JW, Ryoo ZY. Enforced expression of roquin protein in T cells exacerbates the incidence and severity of experimental arthritis. J Biol Chem 2012; 287:42269-77. [PMID: 23066015 DOI: 10.1074/jbc.m112.374835] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
To investigate the role of Roquin, a RING-type ubiquitin ligase family member, we used transgenic mice with enforced Roquin expression in T cells, with collagen-induced arthritis (CIA). Wild-type (WT) and Roquin transgenic (Tg) mice were immunized with bovine type II collagen (CII). Arthritis severity was evaluated by clinical score; histopathologic CIA severity; proinflammatory and anti-inflammatory cytokine levels; anti-CII antibody levels; and populations of Th1, Th2, germinal center B cells, and follicular helper T cells in CIA. T cell proliferation in vitro and cytokine levels were determined to assess the response to CII. Roquin Tg mice developed more severe CIA and joint destruction compared with WT mice. Production of TNF-α, IFN-γ, IL-6, and pathogenic anti-collagen CII-specific IgG and IgG2a antibodies was increased in Roquin Tg mice. In addition, in vitro T cell assays showed increased proliferation and proinflammatory cytokine production in response to CII as a result of enforced Roquin expression in T cells. Furthermore, the Th1/Th2 balance was altered by an increased Th1 and decreased Th2 population. These findings suggest that overexpression of Roquin exacerbates the development of CIA and that enforced expression of Roquin in T cells may promote autoimmune diseases such as CIA.
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Affiliation(s)
- Young Rae Ji
- School of Life Sciences and Biotechnology, Kyungpook National University, 1370 Sankyuk-dong, Buk-ku, Daegu 702-701, Korea
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27
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Ehrlichia chaffeensis TRP32 interacts with host cell targets that influence intracellular survival. Infect Immun 2012; 80:2297-306. [PMID: 22547548 DOI: 10.1128/iai.00154-12] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Ehrlichia chaffeensis is an obligately intracellular bacterium that exhibits tropism for mononuclear phagocytes and survives by evading host cell defense mechanisms. Recently, molecular interactions of E. chaffeensis tandem repeat proteins 47 and 120 (TRP47 and -120) and the eukaryotic host cell have been described. In this investigation, yeast two-hybrid analysis demonstrated that an E. chaffeensis type 1 secretion system substrate, TRP32, interacts with a diverse group of human proteins associated with major biological processes of the host cell, including protein synthesis, trafficking, degradation, immune signaling, cell signaling, iron metabolism, and apoptosis. Eight target proteins, including translation elongation factor 1 alpha 1 (EF1A1), deleted in azoospermia (DAZ)-associated protein 2 (DAZAP2), ferritin light polypeptide (FTL), CD63, CD14, proteasome subunit beta type 1 (PSMB1), ring finger and CCCH-type domain 1 (RC3H1), and tumor protein p53-inducible protein 11 (TP53I11) interacted with TRP32 as determined by coimmunoprecipitation assays, colocalization with TRP32 in HeLa and THP-1 cells, and/or RNA interference. Interactions between TRP32 and host targets localized to the E. chaffeensis morulae or in the host cell cytoplasm adjacent to morulae. Common or closely related interacting partners of E. chaffeensis TRP32, TRP47, and TRP120 demonstrate a molecular convergence on common cellular processes and molecular cross talk between Ehrlichia TRPs and host targets. These findings further support the role of TRPs as effectors that promote intracellular survival.
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Abstract
Ubiquitination, the covalent attachment of ubiquitin molecules to proteins, is emerging as a widely utilized mechanism for rapidly regulating cell signaling. Recent studies indicate that ubiquitination plays potent roles in regulating a variety of signals in both innate and adaptive immune cells. Here, we will review recent studies of ubiquitin ligases, ubiquitin chain linkages, and ubiquitin binding proteins that highlight the diversity and specificity of ubiquitin dependent functions in immune cells. We will also review studies that shed light on how ubiquitination signals are integrated in cell-type-specific fashion to regulate the immune system in vivo.
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Affiliation(s)
- Barbara A Malynn
- Department of Medicine, Biomedical Sciences Program, University of California, San Francisco, San Francisco, CA 94143-0451, USA
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Ramon HE, Riling CR, Bradfield J, Yang B, Hakonarson H, Oliver PM. The ubiquitin ligase adaptor Ndfip1 regulates T cell-mediated gastrointestinal inflammation and inflammatory bowel disease susceptibility. Mucosal Immunol 2011; 4:314-24. [PMID: 20962770 PMCID: PMC3905456 DOI: 10.1038/mi.2010.69] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Nedd4 family interacting protein 1 (Ndfip1) is an adaptor protein that regulates Itch, an E3 ubiquitin ligase that ubiquitylates JunB, thereby preventing interleukin (IL)-4 and IL-5 production. Mice lacking Ndfip1 or Itch develop T helper type 2 (T(H)2)-mediated inflammation in the skin and lungs and die prematurely. In this study we show that Ndfip1-/- mice also develop inflammation in the gastrointestinal tract. Inflammation is characterized by infiltration of eosinophils and T cells and is accompanied by a failure to gain weight. T cells are both necessary and sufficient for eosinophil recruitment and inflammation. This is because Ndfip1-/- T cells become activated and produce IL-5. Itch mutant mice develop much less severe gastrointestinal inflammation, suggesting that Ndfip1 regulation of Itch cannot entirely account for this phenotype and that Ndfip1 has both Itch-dependent and Itch-independent roles. Ndfip1 may also regulate human disease. We found single-nucleotide polymorphisms in the Ndfip1 locus that associate with inflammatory bowel disease. Taken together, our data support a role for Ndfip1 in gastrointestinal inflammation in both mice and humans.
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Affiliation(s)
- HE Ramon
- University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA
| | - CR Riling
- Cell Pathology Division, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - J Bradfield
- Department of Pediatrics, CHOP, Philadelphia, Pennsylvania, USA
| | - B Yang
- Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - H Hakonarson
- University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA,Department of Pediatrics, CHOP, Philadelphia, Pennsylvania, USA,The Center for Applied Genomics, CHOP, Philadelphia, Pennsylvania, USA,The Division of Human Genetics, CHOP, Philadelphia, Pennsylvania, USA
| | - PM Oliver
- Cell Pathology Division, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA,Department of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA
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Mechanisms that regulate peripheral immune responses to control organ-specific autoimmunity. Clin Dev Immunol 2011; 2011:294968. [PMID: 21603204 PMCID: PMC3095406 DOI: 10.1155/2011/294968] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2011] [Accepted: 02/16/2011] [Indexed: 01/10/2023]
Abstract
The immune system must balance the need to maintain a diverse repertoire of lymphocytes to be able to fight infection with the need to maintain tolerance to self-proteins. The immune system places strict regulation over the ability of T cells to produce the major T cell growth factor interleukin 2 as this cytokine can influence a variety of immune outcomes. T cells require the delivery of two signals, one through the antigen receptor and a second through the costimulatory receptor CD28. The immune system uses a variety of E3 ubiquitin ligases to target signaling proteins that function downstream of the TCR and CD28 receptors. Mutations in these E3 ligases can lead to a breakdown in immune tolerance and development of autoimmunity. This paper will examine the role of a range of E3 ubiquitin ligases and signaling pathways that influence the development of T-cell effector responses and the development of organ-specific autoimmune diseases such as type 1 diabetes.
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31
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Yingchun L, Xiujuan Q, Jinglei Q, Ye Z, Jing L, Yuee T, Xuejun H, Kezuo H, Yunpeng L. E3 ubiquitin ligase Cbl-b potentiates the apoptotic action of arsenic trioxide by inhibiting the PI3K/Akt pathway. Braz J Med Biol Res 2010; 44:105-11. [PMID: 21180886 DOI: 10.1590/s0100-879x2010007500142] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2010] [Accepted: 12/06/2010] [Indexed: 11/22/2022] Open
Abstract
Arsenic trioxide (ATO) is a strong inducer of apoptosis in malignant hematological cells. Inducible phosphatidyl inositol 3 kinase (PI3K)-Akt activation promotes resistance to ATO. In the present study, we evaluated whether E3 ubiquitin ligase Cbl-b, a negative regulator of PI3K activation, is involved in the action of ATO. The effect of ATO on cell viability was measured by the Trypan blue exclusion assay or by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Apoptosis was determined by flow cytometry and protein expression was assayed by Western blotting. ATO decreased the viability of HL60 cells and induced cellular apoptosis, which was accompanied by transient activation of Akt. The PI3K/Akt inhibitor, LY294002, significantly increased ATO-induced apoptosis (P < 0.05). In addition, ATO up-regulated the expression of Cbl-b proteins. Furthermore, ATO inhibited cell viability with an IC50 of 18.54 μM at 24 h in rat basophilic leukemia-2H3 cells. ATO induced cellular apoptosis with transient activation of Akt and Cbl-b was also up-regulated. Rat basophilic leukemia-2H3 cells transfected with a dominant negative (DN) Cbl-b mutation showed overexpression of Cbl-b (DN) and enhanced Akt activation. Compared with cells transfected with vector, ATO-induced apoptosis was decreased and G2/M phase cells were increased at the same concentration (P < 0.05). The PI3K/Akt inhibitor, LY294002, re-sensitized Cbl-b (DN) overexpressing cells to ATO and reversed G2/M arrest (P < 0.05). Taken together, these results suggest that Cbl-b potentiates the apoptotic action of ATO by inhibition of the PI3K/Akt pathway.
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Affiliation(s)
- Li Yingchun
- Department of Medical Oncology, China Medical University
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Whiting CC, Su LL, Lin JT, Fathman CG. GRAIL: a unique mediator of CD4 T-lymphocyte unresponsiveness. FEBS J 2010; 278:47-58. [PMID: 21078124 DOI: 10.1111/j.1742-4658.2010.07922.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
GRAIL (gene related to anergy in lymphocytes, also known as RNF128), an ubiquitin-protein ligase (E3), utilizes a unique single transmembrane protein with a split-function motif, and is an important gatekeeper of T-cell unresponsiveness. Although it may play a role in other CD4 T-cell functions including activation, survival and differentiation, GRAIL is most well characterized as a negative regulator of T-cell receptor responsiveness and cytokine production. Here, we review the recent literature on this remarkable E3 in the regulation of human and mouse CD4 T-cell unresponsiveness.
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Affiliation(s)
- Chan C Whiting
- Department of Medicine, Stanford University, Stanford, CA 94305, USA
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33
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Stromnes IM, Blattman JN, Tan X, Jeevanjee S, Gu H, Greenberg PD. Abrogating Cbl-b in effector CD8(+) T cells improves the efficacy of adoptive therapy of leukemia in mice. J Clin Invest 2010; 120:3722-34. [PMID: 20890046 DOI: 10.1172/jci41991] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2010] [Accepted: 07/28/2010] [Indexed: 01/28/2023] Open
Abstract
The clinical use of adoptive immunotherapy with tumor-reactive T cells to treat established cancers is limited in part by the poor in vivo survival and function of the transferred T cells. Although administration of exogenous cytokines such as IL-2 can promote T cell survival, such strategies have many nonspecific activities and are often associated with toxicity. We show here that abrogating expression of Casitas B-lineage lymphoma b (Cbl-b), a negative regulator of lymphocyte activation, in tumor-reactive CD8(+) T cells expanded ex vivo increased the efficacy of adoptive immunotherapy of disseminated leukemia in mice. Mechanistically, Cbl-b abrogation bypassed the requirement for exogenous IL-2 administration for tumor eradication in vivo. In addition, CD8(+) T cells lacking Cbl-b demonstrated a lower threshold for activation, better survival following target recognition and stimulation, and enhanced proliferative responses as a result of both IL-2-dependent and -independent pathways. Importantly, siRNA knockdown of Cbl-b in human CD8(+)CD28- effector T cell clones similarly restored IL-2 production and proliferation following target recognition independent of exogenous IL-2, enhanced IFN-γ production, and increased target avidity. Thus, abrogating Cbl-b expression in effector T cells may improve the efficacy of adoptive therapy of some human malignancies.
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Affiliation(s)
- Ingunn M Stromnes
- Department of Immunology, University of Washington, Seattle, Washington 98195-6425, USA
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34
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Fighting cancers from within: augmenting tumor immunity with cytokine therapy. Trends Pharmacol Sci 2010; 31:356-63. [DOI: 10.1016/j.tips.2010.05.003] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2009] [Revised: 05/14/2010] [Accepted: 05/19/2010] [Indexed: 12/26/2022]
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Pellegrini M, Mak TW. Tumor immune therapy: Lessons from infection and implications for cancer - Can IL-7 help overcome immune inhibitory networks? Eur J Immunol 2010; 40:1852-61. [DOI: 10.1002/eji.201040603] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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36
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Li J, Wan Y, Guo Q, Zou L, Zhang J, Fang Y, Zhang J, Zhang J, Fu X, Liu H, Lu L, Wu Y. Altered microRNA expression profile with miR-146a upregulation in CD4+ T cells from patients with rheumatoid arthritis. Arthritis Res Ther 2010; 12:R81. [PMID: 20459811 PMCID: PMC2911863 DOI: 10.1186/ar3006] [Citation(s) in RCA: 207] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2010] [Revised: 04/20/2010] [Accepted: 05/11/2010] [Indexed: 12/14/2022] Open
Abstract
Introduction Increasing evidence indicates that microRNAs (miRNAs) play a critical role in the pathogenesis of inflammatory diseases. The aim of the study was to investigate the expression pattern and function of miRNAs in CD4+ T cells from patients with rheumatoid arthritis (RA). Methods The expression profile of miRNAs in CD4+ T cells from synovial fluid (SF) and peripheral blood of 33 RA patients was determined by microarray assay and validated by qRT-PCR analysis. The correlation between altered expression of miRNAs and cytokine levels was determined by linear regression analysis. The role of miR-146a overexpression in regulating T cell apoptosis was evaluated by flow cytometry. A genome-wide gene expression analysis was further performed to identify miR-146a-regulated genes in T cells. Results miRNA expression profile analysis revealed that miR-146a expression was significantly upregulated while miR-363 and miR-498 were downregulated in CD4+ T cells of RA patients. The level of miR-146a expression was positively correlated with levels of tumor necrosis factor-alpha (TNF-α), and in vitro studies showed TNF-α upregulated miR-146a expression in T cells. Moreover, miR-146a overexpression was found to suppress Jurkat T cell apoptosis. Finally, transcriptome analysis of miR-146a overexpression in T cells identified Fas associated factor 1 (FAF1) as a miR-146a-regulated gene, which was critically involved in modulating T cell apoptosis. Conclusions We have detected increased miR-146a in CD4+ T cells of RA patients and its close correlation with TNF-α levels. Our findings that miR-146a overexpression suppresses T cell apoptosis indicate a role of miR-146a in RA pathogenesis and provide potential novel therapeutic targets.
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Affiliation(s)
- Jingyi Li
- Institute of Immunology, PLA, Third Military Medical University, 30# Gaotanyan Street, District Shipingba, Chongqing 400038, PR China
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38
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Abstract
Dysregulation of the UPS (ubiquitin-proteasome system) has been implicated in a wide range of pathologies including cancer, neurodegeneration and viral infection. Inhibiting the proteasome has been shown to be an effective therapeutic strategy in humans; however, toxicity with this target remains high. E3s (Ub-protein ligases) represent an alternative attractive therapeutic target in the UPS. In this paper, we will discuss current platforms that report on E3 ligase activity and can detect E3 inhibitors, and underline the advantages and disadvantages of each approach.
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39
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Harnett W, Harnett MM. Helminth-derived immunomodulators: can understanding the worm produce the pill? Nat Rev Immunol 2010; 10:278-84. [PMID: 20224568 DOI: 10.1038/nri2730] [Citation(s) in RCA: 154] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Helminths may protect humans against allergic and autoimmune diseases and, indeed, defined helminth-derived products have recently been shown to prevent the development of such inflammatory diseases in mouse models. Here, we propose that helminth-derived products not only have therapeutic potential but can also be used as unique tools for defining key molecular events in the induction of an anti-inflammatory response and, therefore, for defining new therapeutic targets.
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Affiliation(s)
- William Harnett
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK.
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40
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Li Y, Yang SL, Tang ZL, Cui WT, Mu YL, Chu MX, Zhao SH, Wu ZF, Li K, Peng KM. Expression and SNP association analysis of porcine FBXL4 gene. Mol Biol Rep 2010; 37:579-85. [PMID: 19768576 DOI: 10.1007/s11033-009-9825-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2009] [Accepted: 09/03/2009] [Indexed: 10/20/2022]
Abstract
As a kind of E3 ligase, the product of FBXL4 gene belongs to a member of FBLs which is the biggest eukaryotic subfamily of F-BOX proteins, it can recognize some substrate through particular protein-protein interaction domains. To investigate its functions, the polymorphism and association analysis was analyzed. The partial cDNA of porcine FBXL4 with 2384 bp long was first cloned; the deduced protein comprises a conserved F-BOX domain at position from the 277th to 332nd amino acid. The phylogenetic tree indicated porcine FBXL4 has the closest genetic relationship with bovine FBXL4 than other selected animal species. Ten tissue expression level of porcine FBXL4 mRNA fluctuated remarkably in a large range by quantitative RT-PCR analysis. For two identified SNPs, the genotyping analysis of Tail showed TT genotype owned dominance in introduced Landrace pig and miniature Guizhou and Wuzhishan breeds, but CC genotype was more than two other genotypes in miniature Laiwu breed. While in another genotyping analysis of BsaJI, CC genotype was obviously more than other genotypes in two kinds of Chinese miniature pig breeds and introduced Landrace pig breeds. Furthermore, the association analysis with immune traits and blood parameters revealed that SNP Tail was significantly associated with the lymphocyte percentage (P = 0.0166) and the antibody levels for pseudorabies virus vaccination (P = 0.0001) of neonate piglets at 0 day. Meanwhile, SNP BsaJI was significantly associated with lymphocyte percentage of individuals at 32 days (P = 0.0351), neutrophil percentage (P = 0.0005), the absolute lymphocyte count (P = 0.0458), and the mixed cells (P = 0.0010) of neonate piglets at 0 day.
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Affiliation(s)
- Y Li
- The Key Laboratory for Farm Animal Genetic Resources and Utilization of Ministry of Agriculture of China, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, People's Republic of China
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41
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Eldridge AG, O'Brien T. Therapeutic strategies within the ubiquitin proteasome system. Cell Death Differ 2010; 17:4-13. [PMID: 19557013 DOI: 10.1038/cdd.2009.82] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The ubiquitin-dependent proteolysis system (UPS) is the main driver of regulated protein degradation in all eukaryotic cells, and it is becoming increasingly clear that defects within this pathway drive a large number of human pathologies. Recent success in the use of proteasome inhibitors in the treatment of hematological malignancies validates the UPS as a viable therapeutic pathway, and substantial effort is now focused on the development of both second-generation proteasome inhibitors as well as novel strategies for the inhibition of upstream UPS enzymes. In this review we discuss the potential 'druggability' of key nodes within the UPS and summarize recent advances within the field.
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Affiliation(s)
- A G Eldridge
- Department of Cell Regulation, Genentech Inc., South San Francisco, CA 94080, USA.
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42
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Qu JL, Qu XJ, Qu JL, Qu XJ, Zhao MF, Teng YE, Zhang Y, Hou KZ, Jiang YH, Yang XH, Liu YP. The role of cbl family of ubiquitin ligases in gastric cancer exosome-induced apoptosis of Jurkat T cells. Acta Oncol 2009; 48:1173-80. [PMID: 19863226 DOI: 10.3109/02841860903032817] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
BACKGROUND. Exosomes are nanometer-sized vesicles with immunomodulatory functions, which are released by a diverse range of living cells. Although recent studies have shown that tumor-derived exosomes can suppress the function of T cells, the molecular mechanisms are not well understood. In the present study, we investigated the role of the Casitas B lineage lymphoma (cbl) family of ubiquitin ligases in gastric cancer exosome-induced apoptosis of Jurkat T cells. MATERIALS AND METHODS. By serial centrifugation and sucrose gradient ultracentrifugation, we isolated and purified the exosomes from gastric cancer SGC7901 cells, and identified them by electron microscopy and Western blotting. Cell apoptosis was detected using propidium iodide staining. Western blotting and RT-PCR was exploited to evaluate the expression of proteins and mRNA, respectively. RESULTS. Gastric cancer exosomes induced Jurkat T cell apoptosis in a time- and dose-dependent manner and activated caspases 3, 8 and 9. The expression of Cbl-b and c-Cbl was up-regulated during exosome-induced apoptosis of cells. Meanwhile, exosomes induced ubiquitination of the p85 subunit of phosphoinositide 3-kinase (PI3K) and reduced downstream Akt activity. Inhibition of proteasome led to partial restoration of Akt activity and cell apoptosis. DISCUSSION AND CONCLUSIONS. The Cbl family of ubiquitin ligases might be involved in regulation of exosome-induced apoptosis of Jurkat T cells by increasing PI3K proteasome degradation, inactivation of PI3K/Akt signaling, thus mediating some effects of caspase activation.
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Affiliation(s)
- Jing-Lei Qu
- Department of Medical Oncology, The First Hospital, China Medical University, NO.155, North Nanjing Street, Heping District, Shenyang, 110001, Liaoning Province, China
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Szigyarto CA, Sibbons P, Williams G, Uhlen M, Metcalfe SM. The E3 ligase axotrophin/MARCH-7: protein expression profiling of human tissues reveals links to adult stem cells. J Histochem Cytochem 2009; 58:301-8. [PMID: 19901269 DOI: 10.1369/jhc.2009.954420] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Axotrophin/MARCH-7 was first identified in mouse embryonic stem cells as a neural stem cell gene. Using the axotrophin/MARCH-7 null mouse, we discovered profound effects on T lymphocyte responses, including 8-fold hyperproliferation and 5-fold excess release of the stem cell cytokine leukemia inhibitory factor (LIF). Our further discovery that axotrophin/MARCH-7 is required for targeted degradation of the LIF receptor subunit gp190 implies a direct role in the regulation of LIF signaling. Bioinformatics studies revealed a highly conserved RING-CH domain in common with the MARCH family of E3-ubiquitin ligases, and accordingly, axotrophin was renamed "MARCH-7." To probe protein expression of human axotrophin/MARCH-7, we prepared antibodies against different domains of the protein. Each antibody bound its specific target epitope with high affinity, and immunohistochemistry cross-validated target specificity. Forty-eight human tissue types were screened. Epithelial cells stained strongly, with trophoblasts having the greatest staining. In certain tissues, specific cell types were selectively positive, including neurons and neuronal progenitor cells in the hippocampus and cerebellum, endothelial sinusoids of the spleen, megakaryocytes in the bone marrow, crypt stem cells of the small intestine, and alveolar macrophages in the lung. Approximately 20% of central nervous system neuropils were positive. Notably, axotrophin/MARCH-7 has an expression profile that is distinct from that of other MARCH family members. This manuscript contains online supplemental material at http://www.jhc.org. Please visit this article online to view these materials.
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Affiliation(s)
- Cristina A Szigyarto
- Human Proteome Resource, School of Biotechnology, Department of Proteomics, Royal Institute of Technology, Stockholm, Sweden
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E3 ubiquitin ligase GRAIL controls primary T cell activation and oral tolerance. Proc Natl Acad Sci U S A 2009; 106:16770-5. [PMID: 19805371 DOI: 10.1073/pnas.0908957106] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
T cell unresponsiveness or anergy is one of the mechanisms that maintain inactivity of self-reactive lymphocytes. E3 ubiquitin ligases are important mediators of the anergic state. The RING finger E3 ligase GRAIL is thought to selectively function in anergic T cells but its mechanism of action and its role in vivo are largely unknown. We show here that genetic deletion of Grail in mice leads not only to loss of an anergic phenotype in various models but also to hyperactivation of primary CD4(+) T cells. Grail(-/-) CD4(+) T cells hyperproliferate in vitro to TCR stimulation alone or with concomitant anti-CD28 costimulation, with transient increased survival. In vitro differentiated T helper 1 cells show slight but significant hypersecretion of IFN-gamma in Grail(-/-) mice whereas Th2 and Th17 cytokine secretions are unchanged. Consistent with defective in vitro anergy, oral tolerance is abolished in vivo in OT-II TCR transgenic Grail(-/-) mice fed with ovalbumin. In experimental allergic encephalitis, a model of organ-specific autoimmunity, oral tolerization with myelin basic protein was abrogated as well in Grail(-/-) mice. On the protein level, Grail(-/-) naïve T cells show no significant differences of total and phosphorylated levels of ZAP70, phospholipase Cgamma1, and MAP kinases p38 and JNK but elevated baseline levels of MAP kinase ERK1/2. In summary, we define a role for GRAIL in primary T cell activation, survival, and differentiation. In addition, we formally prove an indispensable role for GRAIL in T cell anergy and oral tolerance-a promising, antigen-specific strategy to treat autoimmune diseases.
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Carpino N, Chen Y, Nassar N, Oh HW. The Sts proteins target tyrosine phosphorylated, ubiquitinated proteins within TCR signaling pathways. Mol Immunol 2009; 46:3224-31. [PMID: 19733910 DOI: 10.1016/j.molimm.2009.08.015] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2009] [Revised: 08/11/2009] [Accepted: 08/12/2009] [Indexed: 10/20/2022]
Abstract
The T cell receptor (TCR) detects the presence of infectious pathogens and activates numerous intracellular signaling pathways. Protein tyrosine phosphorylation and ubiquitination serve as key regulatory mechanisms downstream of the TCR. Negative regulation of TCR signaling pathways is important in controlling the immune response, and the Suppressor of TCR Signaling proteins (Sts-1 and Sts-2) have been shown to function as critical negative regulators of TCR signaling. Although their mechanism of action has yet to be fully uncovered, it is known that the Sts proteins possess intrinsic phosphatase activity. Here, we demonstrate that Sts-1 and Sts-2 are instrumental in down-modulating proteins that are dually modified by both protein tyrosine phosphorylation and ubiquitination. Specifically, both naïve and activated T cells derived from genetically engineered mice that lack the Sts proteins display strikingly elevated levels of tyrosine phosphorylated, ubiquitinated proteins following TCR stimulation. The accumulation of the dually modified proteins is transient, and in activated T cells but not naïve T cells is significantly enhanced by co-receptor engagement. Our observations hint at a novel regulatory mechanism downstream of the T cell receptor.
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Affiliation(s)
- Nick Carpino
- Department of Molecular Genetics and Microbiology, Room 130, Life Sciences Building, Stony Brook University, Stony Brook, NY 11794-5222, USA.
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46
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A comprehensive framework of E2-RING E3 interactions of the human ubiquitin-proteasome system. Mol Syst Biol 2009; 5:295. [PMID: 19690564 PMCID: PMC2736652 DOI: 10.1038/msb.2009.55] [Citation(s) in RCA: 112] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2008] [Accepted: 07/07/2009] [Indexed: 12/28/2022] Open
Abstract
Covalent attachment of ubiquitin to substrates is crucial to protein degradation, transcription regulation and cell signalling. Highly specific interactions between ubiquitin-conjugating enzymes (E2) and ubiquitin protein E3 ligases fulfil essential roles in this process. We performed a global yeast-two hybrid screen to study the specificity of interactions between catalytic domains of the 35 human E2s with 250 RING-type E3s. Our analysis showed over 300 high-quality interactions, uncovering a large fraction of new E2–E3 pairs. Both within the E2 and the E3 cohorts, several members were identified that are more versatile in their interaction behaviour than others. We also found that the physical interactions of our screen compare well with reported functional E2–E3 pairs in in vitro ubiquitination experiments. For validation we confirmed the interaction of several versatile E2s with E3s in in vitro protein interaction assays and we used mutagenesis to alter the E3 interactions of the E2 specific for K63 linkages, UBE2N(Ubc13), towards the K48-specific UBE2D2(UbcH5B). Our data provide a detailed, genome-wide overview of binary E2–E3 interactions of the human ubiquitination system.
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47
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Schmitz ML. Activation of T Cells: Releasing the Brakes by Proteolytic Elimination of Cbl-b. Sci Signal 2009; 2:pe38. [DOI: 10.1126/scisignal.276pe38] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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Shikama N, Nusspaumer G, Holländer GA. Clearing the AIRE: on the pathophysiological basis of the autoimmune polyendocrinopathy syndrome type-1. Endocrinol Metab Clin North Am 2009; 38:273-88, vii. [PMID: 19328411 DOI: 10.1016/j.ecl.2009.01.011] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Autoimmune polyendocrine syndrome type-1 clinically manifests as the triad of hypoparathyroidism, primary adrenocortical insufficiency, and chronic mucocutaneous candidiasis. Mutations in the gene that encodes the autoimmune regulator protein, AIRE, have been identified as the cause of the autoimmune polyendocrine syndrome type-1. The loss of immunologic tolerance to tissue-restricted antigens consequent to an absence of AIRE expression in the thymus results in the thymic export of autoreactive T cells that initiate autoimmunity. In this article, we discuss the role of AIRE in autoimmune polyendocrine syndrome type-1 and identify issues that still need to be addressed to fully understand the molecular pathophysiology of this complex syndrome.
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Affiliation(s)
- Noriko Shikama
- Laboratory of Pediatric Immunology, Department of Biomedicine, University of Basel and The University Children's Hospital (UKBB), Basel, Switzerland
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Li Y, Qu X, Qu J, Zhang Y, Liu J, Teng Y, Hu X, Hou K, Liu Y. Arsenic trioxide induces apoptosis and G2/M phase arrest by inducing Cbl to inhibit PI3K/Akt signaling and thereby regulate p53 activation. Cancer Lett 2009; 284:208-15. [PMID: 19457607 DOI: 10.1016/j.canlet.2009.04.035] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2008] [Revised: 03/23/2009] [Accepted: 04/20/2009] [Indexed: 10/20/2022]
Abstract
Arsenic trioxide (ATO) strongly induces apoptosis in acute promyelocytic leukemia (APL), but it induces cell cycle arrest in most solid tumors. In this study, we investigated the mechanism of ATO action on APL-derived NB4 cells and gastric cancer cell lines. ATO decreased the viability of both cell lines, but gastric cancer cells were much less susceptible. ATO-induced G2/M phase arrest and p53 degradation in gastric cancer MGC803 cells. In contrast, ATO-induced apoptosis in NB4 cells without degradation of p53. Both processes were accompanied by transient activation of Akt. The PI3K/Akt inhibitor LY294002 significantly increased the amount of p53 protein and ATO-induced apoptosis in both cell lines and decreased G2/M phase arrest of MGC803 cells. In addition, ATO up-regulated the expression of Cbl proteins in both cell lines. Inhibition of Cbl with the proteasome inhibitor Ps341 decreased apoptosis in NB4 cells and increased the G2/M phase arrest of MGC803 cells, and it also prolonged the activation of PI3K/Akt by ATO. Consistent results with those in MGC803 cells were showed in gastric cancer cell BGC823 and SGC7901 after ATO treatment. These results demonstrate that inhibition of PI3K/Akt signaling by Cbl is involved in both ATO-induced apoptosis of NB4 cells and ATO-induced G2/M phase arrest of gastric cancer cells. Cbl achieved these effects probably via its regulating PI3K/Akt pathway, and thereby modulated p53 activation.
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Affiliation(s)
- Yingchun Li
- Department of Medical Oncology, The First Hospital, China Medical University, Heping District, Shenyang City 110001, China
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Lin JT, Lineberry NB, Kattah MG, Su LL, Utz PJ, Fathman CG, Wu L. Naive CD4 t cell proliferation is controlled by mammalian target of rapamycin regulation of GRAIL expression. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2009; 182:5919-28. [PMID: 19414743 PMCID: PMC2853371 DOI: 10.4049/jimmunol.0803986] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
In this study, we demonstrate that the E3 ubiquitin ligase gene related to anergy in lymphocytes (GRAIL) is expressed in quiescent naive mouse and human CD4 T cells and has a functional role in inhibiting naive T cell proliferation. Following TCR engagement, CD28 costimulation results in the expression of IL-2 whose signaling through its receptor activates the Akt-mammalian target of rapamycin (mTOR) pathway. Activation of mTOR allows selective mRNA translation, including the epistatic regulator of GRAIL, Otubain-1 (Otub1), whose expression results in the degradation of GRAIL and allows T cell proliferation. The activation of mTOR appears to be the critical component of IL-2R signaling regulating GRAIL expression. CTLA4-Ig treatment blocks CD28 costimulation and resultant IL-2 expression, whereas rapamycin and anti-IL-2 treatment block mTOR activation downstream of IL-2R signaling. Thus, all three of these biotherapeutics inhibit mTOR-dependent translation of mRNA transcripts, resulting in blockade of Otub1 expression, maintenance of GRAIL, and inhibition of CD4 T cell proliferation. These observations provide a mechanistic pathway sequentially linking CD28 costimulation, IL-2R signaling, and mTOR activation as important requirements for naive CD4 T cell proliferation through the regulation of Otub1 and GRAIL expression. Our findings also extend the role of GRAIL beyond anergy induction and maintenance, suggesting that endogenous GRAIL regulates general cell cycle and proliferation of primary naive CD4 T cells.
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Affiliation(s)
- Jack T. Lin
- Stanford University School of Medicine, Department of Medicine, Division of Immunology and Rheumatology, Stanford, CA 94305
| | - Neil B. Lineberry
- Stanford University School of Medicine, Department of Medicine, Division of Immunology and Rheumatology, Stanford, CA 94305
| | - Michael G. Kattah
- Stanford University School of Medicine, Department of Medicine, Division of Immunology and Rheumatology, Stanford, CA 94305
| | - Leon L. Su
- Stanford University School of Medicine, Department of Medicine, Division of Immunology and Rheumatology, Stanford, CA 94305
| | - Paul J. Utz
- Stanford University School of Medicine, Department of Medicine, Division of Immunology and Rheumatology, Stanford, CA 94305
| | - C. Garrison Fathman
- Stanford University School of Medicine, Department of Medicine, Division of Immunology and Rheumatology, Stanford, CA 94305
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