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Miraki Feriz A, Bahraini F, Khosrojerdi A, Azarkar S, Sajjadi SM, HosseiniGol E, Honardoost MA, Saghafi S, Silvestris N, Leone P, Safarpour H, Racanelli V. Deciphering the immune landscape of head and neck squamous cell carcinoma: A single-cell transcriptomic analysis of regulatory T cell responses to PD-1 blockade therapy. PLoS One 2023; 18:e0295863. [PMID: 38096229 PMCID: PMC10721039 DOI: 10.1371/journal.pone.0295863] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Accepted: 11/30/2023] [Indexed: 12/17/2023] Open
Abstract
Immunotherapy is changing the Head and Neck Squamous Cell Carcinoma (HNSCC) landscape and improving outcomes for patients with recurrent or metastatic HNSCC. A deeper understanding of the tumor microenvironment (TME) is required in light of the limitations of patients' responses to immunotherapy. Here, we aimed to examine how Nivolumab affects infiltrating Tregs in the HNSCC TME. We used single-cell RNA sequencing data from eight tissues isolated from four HNSCC donors before and after Nivolumab treatment. Interestingly, the study found that Treg counts and suppressive activity increased following Nivolumab therapy. We also discovered that changes in the CD44-SSP1 axis, NKG2C/D-HLA-E axis, and KRAS signaling may have contributed to the increase in Treg numbers. Furthermore, our study suggests that decreasing the activity of the KRAS and Notch signaling pathways, and increasing FOXP3, CTLA-4, LAG-3, and GZMA expression, may be mechanisms that enhance the killing and suppressive capacity of Tregs. Additionally, the result of pseudo-temporal analysis of the HNSCC TME indicated that after Nivolumab therapy, the expression of certain inhibitory immune checkpoints including TIGIT, ENTPD1, and CD276 and LY9, were decreased in Tregs, while LAG-3 showed an increased expression level. The study also found that Tregs had a dense communication network with cluster two, and that certain ligand-receptor pairs, including SPP1/CD44, HLA-E/KLRC2, HLA-E/KLRK1, ANXA1/FPR3, and CXCL9/FCGR2A, had notable changes after the therapy. These changes in gene expression and cell interactions may have implications for the role of Tregs in the TME and in response to Nivolumab therapy.
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Affiliation(s)
- Adib Miraki Feriz
- Student Research Committee, Birjand University of Medical Sciences (BUMS), Birjand, Iran
| | - Fatemeh Bahraini
- Student Research Committee, Birjand University of Medical Sciences (BUMS), Birjand, Iran
| | | | - Setareh Azarkar
- Student Research Committee, Birjand University of Medical Sciences (BUMS), Birjand, Iran
| | | | - Edris HosseiniGol
- Department of Computer Engineering, University of Birjand, Birjand, Iran
| | - Mohammad Amin Honardoost
- Laboratory of Systems Biology and Data Analytics, Genome Institute of Singapore, A*STAR, Singapore, Singapore
| | - Samira Saghafi
- Cellular and Molecular Research Center (CMRC), BUMS, Birjand, Iran
- Department of Internal Medicine, School of Medicine, BUMS, Birjand, Iran
| | - Nicola Silvestris
- Medical Oncology Unit, Department of Human Pathology “G. Barresi”, University of Messina, Messina, Italy
| | - Patrizia Leone
- Department of Biomedical Sciences and Human Oncology, University of Bari "Aldo Moro", Bari, Italy
| | | | - Vito Racanelli
- Centre for Medical Sciences (CISMed), University of Trento and Internal Medicine Division, Santa Chiara Hospital, Provincial Health Care Agency (APSS), Trento, Italy
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2
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Mansour R, El-Orfali Y, Saidu A, Al-Kalamouni H, Mardirossian H, Hanna-Wakim R, Abboud M, Massaad MJ. A novel homozygous mutation in RASGRP1 that predisposes to immune dysregulation and immunodeficiency associated with uncontrolled Epstein-Barr virus-induced B cell proliferation. Clin Immunol 2023; 257:109813. [PMID: 37898412 DOI: 10.1016/j.clim.2023.109813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 10/05/2023] [Accepted: 10/21/2023] [Indexed: 10/30/2023]
Abstract
BACKGROUND RASGRP1-deficiency results in an immune dysregulation and immunodeficiency that manifest as autoimmunity, lymphoproliferation, lymphopenia, defective T cell function, and increased incidence of Epstein-Bar Virus infections and lymphomas. OBJECTIVE To investigate the mechanism of autoimmune hemolytic anemia and infections in a male patient of consanguineous parents from Lebanon. METHODS Genetic diagnosis was obtained using next generation and Sanger sequencing. Protein expression and phosphorylation were determined by immunoblotting. T and B cell development and function were studied by flow cytometry. Cytokine and immunoglobulin secretions were quantified by enzyme-linked immunosorbent assay. RESULTS The patient suffered from severe lymphopenia especially affecting the T cell compartment. Genetic analysis revealed a homozygous insertion of adenine at position 1396_1397 in RASGRP1 that abolished protein expression and downstream Ras signaling. T cells from the patient showed severe activation defects resulting in uncontrolled Epstein-Bar Virus-induced B cell proliferation. B cells from the patient were normal. CONCLUSION This report expands the spectrum of mutations in patients with RasGRP1 deficiency, and provides evidence for the important role RasGRP1 plays in the ability of T cells to control Epstein-Bar Virus-induced B cell proliferation. CLINICAL IMPLICATIONS Following diagnosis, the patient will be maintained on oral valganciclovir and monitored regularly for Epstein-Bar Virus infections to avoid the development of Epstein-Bar Virus- induced B cell lymphoma. He is also candidate for hematopoietic stem cell transplantation.
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Affiliation(s)
- Rana Mansour
- Department of Experimental Pathology, Immunology, and Microbiology, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Youmna El-Orfali
- Department of Experimental Pathology, Immunology, and Microbiology, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Adam Saidu
- Department of Experimental Pathology, Immunology, and Microbiology, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Habib Al-Kalamouni
- Department of Experimental Pathology, Immunology, and Microbiology, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Hagop Mardirossian
- Department of Experimental Pathology, Immunology, and Microbiology, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Rima Hanna-Wakim
- Division of Pediatric Infectious Diseases, Department of Pediatrics and Adolescent Medicine, American University of Beirut Medical Center, Beirut, Lebanon; Center for Infectious Diseases Research, American University of Beirut, Beirut, Lebanon
| | - Miguel Abboud
- Division of Pediatric Hematology Oncology, Department of Pediatrics and Adolescent Medicine, American University of Beirut Medical Center, Beirut, Lebanon; Children's Cancer Center of Lebanon, American University of Beirut Medical Center, Beirut, Lebanon
| | - Michel J Massaad
- Department of Experimental Pathology, Immunology, and Microbiology, Faculty of Medicine, American University of Beirut, Beirut, Lebanon; Division of Pediatric Infectious Diseases, Department of Pediatrics and Adolescent Medicine, American University of Beirut Medical Center, Beirut, Lebanon; Center for Infectious Diseases Research, American University of Beirut, Beirut, Lebanon; Research Center of Excellence in Immunity and Infections, American University of Beirut, Beirut, Lebanon.
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3
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Terracina S, Ferraguti G, Tarani L, Fanfarillo F, Tirassa P, Ralli M, Iannella G, Polimeni A, Lucarelli M, Greco A, Fiore M. Nerve Growth Factor and Autoimmune Diseases. Curr Issues Mol Biol 2023; 45:8950-8973. [PMID: 37998739 PMCID: PMC10670231 DOI: 10.3390/cimb45110562] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 11/06/2023] [Accepted: 11/08/2023] [Indexed: 11/25/2023] Open
Abstract
NGF plays a crucial immunomodulatory role and increased levels are found in numerous tissues during autoimmune states. NGF directly modulates innate and adaptive immune responses of B and T cells and causes the release of neuropeptides and neurotransmitters controlling the immune system activation in inflamed tissues. Evidence suggests that NGF is involved in the pathogenesis of numerous immune diseases including autoimmune thyroiditis, chronic arthritis, multiple sclerosis, systemic lupus erythematosus, mastocytosis, and chronic granulomatous disease. Furthermore, as NGF levels have been linked to disease severity, it could be considered an optimal early biomarker to identify therapeutic approach efficacy. In conclusion, by gaining insights into how these molecules function and which cells they interact with, future studies can devise targeted therapies to address various neurological, immunological, and other disorders more effectively. This knowledge may pave the way for innovative treatments based on NGF manipulation aimed at improving the quality of life for individuals affected by diseases involving neurotrophins.
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Affiliation(s)
- Sergio Terracina
- Department of Experimental Medicine, Sapienza University of Rome, 00185 Rome, Italy
| | - Giampiero Ferraguti
- Department of Experimental Medicine, Sapienza University of Rome, 00185 Rome, Italy
| | - Luigi Tarani
- Department of Maternal Infantile and Urological Sciences, Sapienza University of Rome, 00185 Rome, Italy
| | - Francesca Fanfarillo
- Department of Experimental Medicine, Sapienza University of Rome, 00185 Rome, Italy
| | - Paola Tirassa
- Institute of Biochemistry and Cell Biology (IBBC-CNR), Department of Sensory Organs, Sapienza University of Rome, 00185 Rome, Italy
| | - Massimo Ralli
- Department of Sensory Organs, Sapienza University of Rome, 00185 Roma, Italy
| | - Giannicola Iannella
- Department of Sensory Organs, Sapienza University of Rome, 00185 Roma, Italy
| | - Antonella Polimeni
- Department of Odontostomatological and Maxillofacial Sciences, Sapienza University of Rome, 00185 Rome, Italy
| | - Marco Lucarelli
- Department of Experimental Medicine, Sapienza University of Rome, 00185 Rome, Italy
- Pasteur Institute, Cenci Bolognetti Foundation, Sapienza University of Rome, 00185 Rome, Italy
| | - Antonio Greco
- Department of Sensory Organs, Sapienza University of Rome, 00185 Roma, Italy
| | - Marco Fiore
- Institute of Biochemistry and Cell Biology (IBBC-CNR), Department of Sensory Organs, Sapienza University of Rome, 00185 Rome, Italy
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4
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Kennewick KT, Bensinger SJ. Decoding the crosstalk between mevalonate metabolism and T cell function. Immunol Rev 2023; 317:71-94. [PMID: 36999733 DOI: 10.1111/imr.13200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 03/12/2023] [Accepted: 03/16/2023] [Indexed: 04/01/2023]
Abstract
The mevalonate pathway is an essential metabolic pathway in T cells regulating development, proliferation, survival, differentiation, and effector functions. The mevalonate pathway is a complex, branched pathway composed of many enzymes that ultimately generate cholesterol and nonsterol isoprenoids. T cells must tightly control metabolic flux through the branches of the mevalonate pathway to ensure sufficient isoprenoids and cholesterol are available to meet cellular demands. Unbalanced metabolite flux through the sterol or the nonsterol isoprenoid branch is metabolically inefficient and can have deleterious consequences for T cell fate and function. Accordingly, there is tight regulatory control over metabolic flux through the branches of this essential lipid synthetic pathway. In this review we provide an overview of how the branches of the mevalonate pathway are regulated in T cells and discuss our current understanding of the relationship between mevalonate metabolism, cholesterol homeostasis and T cell function.
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Affiliation(s)
- Kelly T Kennewick
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, California, USA
| | - Steven J Bensinger
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, California, USA
- Department of Molecular and Medical Pharmacology, University of California, Los Angeles, California, USA
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5
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Wang H, Moniruzzaman R, Li L, Ji B, Liu Y, Zuo X, Abbasgholizadeh R, Zhao J, Liu G, Wang R, Tang H, Sun R, Su X, Tan TH, Maitra A, Wang H. Hematopoietic progenitor kinase 1 inhibits the development and progression of pancreatic intraepithelial neoplasia. J Clin Invest 2023; 133:e163873. [PMID: 37140994 PMCID: PMC10266776 DOI: 10.1172/jci163873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Accepted: 05/02/2023] [Indexed: 05/05/2023] Open
Abstract
Ras plays an essential role in the development of acinar-to-ductal metaplasia (ADM) and pancreatic ductal adenocarcinoma (PDAC). However, mutant Kras is an inefficient driver for PDAC development. The mechanisms of the switching from low Ras activity to high Ras activity that are required for development and progression of pancreatic intraepithelial neoplasias (PanINs) are unclear. In this study, we found that hematopoietic progenitor kinase 1 (HPK1) was upregulated during pancreatic injury and ADM. HPK1 interacted with the SH3 domain and phosphorylated Ras GTPase-activating protein (RasGAP) and upregulated RasGAP activity. Using transgenic mouse models of HPK1 or M46, a kinase-dead mutant of HPK1, we showed that HPK1 inhibited Ras activity and its downstream signaling and regulated acinar cell plasticity. M46 promoted the development of ADM and PanINs. Expression of M46 in KrasG12D Bac mice promoted the infiltration of myeloid-derived suppressor cells and macrophages, inhibited the infiltration of T cells, and accelerated the progression of PanINs to invasive and metastatic PDAC, while HPK1 attenuated mutant Kras-driven PanIN progression. Our results showed that HPK1 plays an important role in ADM and the progression of PanINs by regulating Ras signaling. Loss of HPK1 kinase activity promotes an immunosuppressive tumor microenvironment and accelerates the progression of PanINs to PDAC.
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Affiliation(s)
- Hua Wang
- Department of Gastrointestinal Medical Oncology and
| | - Rohan Moniruzzaman
- Department of Pathology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Lei Li
- Department of Pathology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Baoan Ji
- Department of Cancer Biology, Mayo Clinic, Jacksonville, Florida, USA
| | - Yi Liu
- Department of Gastrointestinal Medical Oncology and
| | | | - Reza Abbasgholizadeh
- Department of Pathology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Jun Zhao
- Department of Pathology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Guangchao Liu
- Department of Pathology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Ruiqi Wang
- Department of Pathology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | | | - Ryan Sun
- Department of Biostatistics, and
| | - Xiaoping Su
- Advanced Technology Genomics Core
- Department of Bioinformatics & Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Tse-Hua Tan
- Immunology Research Center, National Health Research Institutes, Zhunan, Taiwan
| | - Anirban Maitra
- Department of Pathology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
- Department of Translational Molecular Pathology and
- Sheikh Ahmed Center for Pancreatic Cancer Research, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Huamin Wang
- Department of Pathology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
- Department of Translational Molecular Pathology and
- Sheikh Ahmed Center for Pancreatic Cancer Research, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
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6
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Meitei HT, Lal G. T cell receptor signaling in the differentiation and plasticity of CD4 + T cells. Cytokine Growth Factor Rev 2023; 69:14-27. [PMID: 36028461 DOI: 10.1016/j.cytogfr.2022.08.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Accepted: 08/17/2022] [Indexed: 02/07/2023]
Abstract
CD4+ T cells are critical components of the adaptive immune system. The T cell receptor (TCR) and co-receptor signaling cascades shape the phenotype and functions of CD4+ T cells. TCR signaling plays a crucial role in T cell development, antigen recognition, activation, and differentiation upon recognition of foreign- or auto-antigens. In specific autoimmune conditions, altered TCR repertoire is reported and can predispose autoimmunity with organ-specific inflammation and tissue damage. TCR signaling modulates various signaling cascades and regulates epigenetic and transcriptional regulation during homeostasis and disease conditions. Understanding the mechanism by which coreceptors and cytokine signals control the magnitude of TCR signal amplification will aid in developing therapeutic strategies to treat inflammation and autoimmune diseases. This review focuses on the role of the TCR signaling cascade and its components in the activation, differentiation, and plasticity of various CD4+ T cell subsets.
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Affiliation(s)
| | - Girdhari Lal
- National Centre for Cell Science, SPPU campus, Ganeshkhind, Pune, MH 411007, India.
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7
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West SJ, Boehning D, Akimzhanov AM. Regulation of T cell function by protein S-acylation. Front Physiol 2022; 13:1040968. [PMID: 36467682 PMCID: PMC9709458 DOI: 10.3389/fphys.2022.1040968] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Accepted: 11/02/2022] [Indexed: 10/26/2023] Open
Abstract
S-acylation, the reversible lipidation of free cysteine residues with long-chain fatty acids, is a highly dynamic post-translational protein modification that has recently emerged as an important regulator of the T cell function. The reversible nature of S-acylation sets this modification apart from other forms of protein lipidation and allows it to play a unique role in intracellular signal transduction. In recent years, a significant number of T cell proteins, including receptors, enzymes, ion channels, and adaptor proteins, were identified as S-acylated. It has been shown that S-acylation critically contributes to their function by regulating protein localization, stability and protein-protein interactions. Furthermore, it has been demonstrated that zDHHC protein acyltransferases, the family of enzymes mediating this modification, also play a prominent role in T cell activation and differentiation. In this review, we aim to highlight the diversity of proteins undergoing S-acylation in T cells, elucidate the mechanisms by which reversible lipidation can impact protein function, and introduce protein acyltransferases as a novel class of regulatory T cell proteins.
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Affiliation(s)
- Savannah J. West
- Department of Biochemistry and Molecular Biology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, United States
- MD Anderson Cancer Center and University of Texas Health Science at Houston Graduate School, Houston, TX, United States
| | - Darren Boehning
- Department of Biomedical Sciences, Cooper Medical School of Rowan University, Camden, NJ, United States
| | - Askar M. Akimzhanov
- Department of Biochemistry and Molecular Biology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, United States
- MD Anderson Cancer Center and University of Texas Health Science at Houston Graduate School, Houston, TX, United States
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8
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Gatti S, Gelzoni G, Catassi GN, Catassi C. The Clinical Spectrum of Inflammatory Bowel Disease Associated With Specific Genetic Syndromes: Two Novel Pediatric Cases and a Systematic Review. Front Pediatr 2021; 9:742830. [PMID: 34765575 PMCID: PMC8576358 DOI: 10.3389/fped.2021.742830] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Accepted: 09/22/2021] [Indexed: 12/21/2022] Open
Abstract
Background and Aims: Inflammatory bowel disease (IBD) is a typical polygenic disorder and less frequently shows a monogenic origin. Furthermore, IBD can originate in the context of specific genetic syndromes associated with a risk of autoimmune disorders. We aimed to systematically evaluate the prevalence of IBD in specific genetic syndromes and to review the clinical characteristics of the published cases. Methods: According to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, studies describing patients with IBD and a genetic syndrome and/or studies indicating the prevalence or incidence of IBD in subjects with a genetic syndrome were included. Results: Forty-six studies describing a total of 67 cases of IBD in six genetic syndromes and two personally assessed unpublished cases were included in the review. The majority of cases were associated with Turner syndrome (TS) (38 cases), Down syndrome (DS) (18 cases) and neurofibromatosis type 1 (NF1) (8 cases). Sporadic cases were described in DiGeorge syndrome (2), Kabuki syndrome (2), and Williams syndrome (1). The prevalence of IBD ranged from 0.67 to 4% in TS and from 0.2 to 1.57% in DS. The incidence of IBD was increased in TS and DS compared to the general population. Eight cases of IBD in TS had a severe/lethal course, many of which described before the year 2000. Two IBD cases in DS were particularly severe. Conclusion: Evidence of a greater prevalence of IBD is accumulating in TS, DS, and NF1. Management of IBD in patients with these genetic conditions should consider the presence of comorbidities and possible drug toxicities. Systematic Review Registration: PROSPERO, identifier: CRD42021249820.
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Affiliation(s)
- Simona Gatti
- Department of Pediatrics, Polytechnic University of Marche, G. Salesi Children's Hospital, Ancona, Italy
| | - Giulia Gelzoni
- Department of Pediatrics, Polytechnic University of Marche, G. Salesi Children's Hospital, Ancona, Italy
| | - Giulia N Catassi
- Department of Maternal and Child Health, Pediatric Gastroenterology and Liver Unit, Umberto I Hospital, Sapienza University of Rome, Rome, Italy
| | - Carlo Catassi
- Department of Pediatrics, Polytechnic University of Marche, G. Salesi Children's Hospital, Ancona, Italy
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9
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Valencic E, Da Lozzo P, Tornese G, Ghirigato E, Facca F, Piscianz E, Faletra F, Taddio A, Tommasini A, Magnolato A. Clinical and Cytometric Study of Immune Involvement in a Heterogeneous Cohort of Subjects With RASopathies and mTORopathies. Front Pediatr 2021; 9:703613. [PMID: 34485194 PMCID: PMC8414575 DOI: 10.3389/fped.2021.703613] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 07/20/2021] [Indexed: 12/02/2022] Open
Abstract
RASopathies and mTORopathies are groups of genetic syndromes associated with increased activation of the RAS-MAPK or the PI3K-AKT-mTOR pathway, resulting in altered cell proliferation during embryonic and postnatal development. The RAS-MAPK and the PI3K-AKT-mTOR pathways are connected to each other and play a crucial role in adaptive immunity. However, with the exception of Activated PI3K delta syndrome (APDS), immune function has not been deeply studied in these disorders. We collected clinical and immunophenotypic data of a cohort of patients with RASopathies and mTORopathies. Overall, we enrolled 47 patients (22 females, 25 males, age 2-40 years): 33 with neurofibromatosis type 1, 11 Noonan syndrome and 3 Bannayan-Riley-Ruvalcaba syndrome. 8 patients reported a history of invasive infections requiring hospitalization and intravenous antibiotic therapy. Only 3 patients reported a history of unusual, difficult-to-treat or deep-seated infection. Adenotonsillectomy was performed in 11 patients (24%). However, in most cases (83%) patients' parents did not perceive their child as more prone to infections than their peers. Lymphocyte subpopulations were analyzed in 37 of the 47 patients (16 female, 21 males, age 1-40 years). Among the studied lymphocyte subsets, the only consistent alteration regarded an increased percentage of immature B cells (recent bone marrow emigrants) in 34 out of 37 (91,9%) patients, and an increased percentage of double negative T cells in 9 patients. In conclusion, although borderline immune abnormalities were present in a significant proportion of subjects and adenotonsillectomy was performed more frequently than expected for the general population, no major immune disturbance was found in this cohort of patients.
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Affiliation(s)
- Erica Valencic
- Department of Pediatrics, Institute for Maternal and Child Health (IRCCS) "Burlo Garofolo", Trieste, Italy
| | - Prisca Da Lozzo
- Department of Medical, Surgical and Health Sciences, University of Trieste, Trieste, Italy
| | - Gianluca Tornese
- Department of Pediatrics, Institute for Maternal and Child Health (IRCCS) "Burlo Garofolo", Trieste, Italy
| | - Elena Ghirigato
- Department of Medical, Surgical and Health Sciences, University of Trieste, Trieste, Italy
| | - Francesco Facca
- Department of Medical, Surgical and Health Sciences, University of Trieste, Trieste, Italy
| | - Elisa Piscianz
- Department of Pediatrics, Institute for Maternal and Child Health (IRCCS) "Burlo Garofolo", Trieste, Italy
| | - Flavio Faletra
- Department of Diagnostics, Institute for Maternal and Child Health (IRCCS) "Burlo Garofolo", Trieste, Italy
| | - Andrea Taddio
- Department of Pediatrics, Institute for Maternal and Child Health (IRCCS) "Burlo Garofolo", Trieste, Italy.,Department of Medical, Surgical and Health Sciences, University of Trieste, Trieste, Italy
| | - Alberto Tommasini
- Department of Pediatrics, Institute for Maternal and Child Health (IRCCS) "Burlo Garofolo", Trieste, Italy.,Department of Medical, Surgical and Health Sciences, University of Trieste, Trieste, Italy
| | - Andrea Magnolato
- Department of Pediatrics, Institute for Maternal and Child Health (IRCCS) "Burlo Garofolo", Trieste, Italy
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10
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Zhang X, Mariano CF, Ando Y, Shen K. Bioengineering tools for probing intracellular events in T lymphocytes. WIREs Mech Dis 2020; 13:e1510. [PMID: 33073545 DOI: 10.1002/wsbm.1510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 09/14/2020] [Accepted: 09/16/2020] [Indexed: 11/11/2022]
Abstract
T lymphocytes are the central coordinator and executor of many immune functions. The activation and function of T lymphocytes are mediated through the engagement of cell surface receptors and regulated by a myriad of intracellular signaling network. Bioengineering tools, including imaging modalities and fluorescent probes, have been developed and employed to elucidate the cellular events throughout the functional lifespan of T cells. A better understanding of these events can broaden our knowledge in the immune systems biology, as well as accelerate the development of effective diagnostics and immunotherapies. Here we review the commonly used and recently developed techniques and probes for monitoring T lymphocyte intracellular events, following the order of intracellular events in T cells from activation, signaling, metabolism to apoptosis. The techniques introduced here can be broadly applied to other immune cells and cell systems. This article is categorized under: Immune System Diseases > Molecular and Cellular Physiology Immune System Diseases > Biomedical Engineering Infectious Diseases > Biomedical Engineering.
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Affiliation(s)
- Xinyuan Zhang
- Department of Biomedical Engineering, University of Southern California, Los Angeles, California, USA
| | - Chelsea F Mariano
- Department of Biomedical Engineering, University of Southern California, Los Angeles, California, USA
| | - Yuta Ando
- Department of Biomedical Engineering, University of Southern California, Los Angeles, California, USA
| | - Keyue Shen
- Department of Biomedical Engineering, University of Southern California, Los Angeles, California, USA.,Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, California, USA.,USC Stem Cell, University of Southern California, Los Angeles, California, USA
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11
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How the T cell signaling network processes information to discriminate between self and agonist ligands. Proc Natl Acad Sci U S A 2020; 117:26020-26030. [PMID: 33020303 DOI: 10.1073/pnas.2008303117] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
T cells exhibit remarkable sensitivity and selectivity in detecting and responding to agonist peptides (p) bound to MHC molecules in a sea of self pMHC molecules. Despite much work, understanding of the underlying mechanisms of distinguishing such ligands remains incomplete. Here, we quantify T cell discriminatory capacity using channel capacity, a direct measure of the signaling network's ability to discriminate between antigen-presenting cells (APCs) displaying either self ligands or a mixture of self and agonist ligands. This metric shows how differences in information content between these two types of peptidomes are decoded by the topology and rates of kinetic proofreading signaling steps inside T cells. Using channel capacity, we constructed numerically substantiated hypotheses to explain the discriminatory role of a recently identified slow LAT Y132 phosphorylation step. Our results revealed that in addition to the number and kinetics of sequential signaling steps, a key determinant of discriminatory capability is spatial localization of a minimum number of these steps to the engaged TCR. Biochemical and imaging experiments support these findings. Our results also reveal the discriminatory role of early negative feedback and necessary amplification conferred by late positive feedback.
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Wei X, Zhao T, Zhang Y, Ai K, Li H, Yang J. Involvement of H-Ras in the adaptive immunity of Nile tilapia by regulating lymphocyte activation. FISH & SHELLFISH IMMUNOLOGY 2019; 89:281-289. [PMID: 30953781 DOI: 10.1016/j.fsi.2019.04.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Revised: 03/24/2019] [Accepted: 04/02/2019] [Indexed: 06/09/2023]
Abstract
H-Ras is a guanosine triphosphatase (GTPase), which acts as a molecular switch and controls multiple important cellular processes including lymphocyte activation and function. However, regulatory mechanism of adaptive immune response by H-Ras remains unclear in non-mammalian animals. In the present study, we investigated the involvement of H-Ras in lymphocyte activation with a teleost model Oreochromis niloticus. H-Ras from O. niloticus (On-H-Ras) is highly conserved with those from other vertebrates. The mRNA of On-H-Ras showed a wide expression pattern in the lymphoid-tissues and with the highest level in liver. After Aeromonas hydrophila infection, transcription of On-H-Ras was significantly induced on day 8 but came back to basal level on day 16, suggesting that On-H-Ras potentially participated in primary response during the adaptive immunity. Furthermore, On-H-Ras mRNA was obviously up-regulated when leukocytes were activated by T lymphocyte mitogen PHA in vitro. Meanwhile, protein level of H-Ras was also augmented once leukocytes were stimulated with lymphocyte receptor signaling agonist PMA and ionomycin. More importantly, once Ras activity was inhibited by specific inhibitor, the up-regulation of lymphocyte activation marker CD122 was obviously impaired during lymphocyte activation process. Therefore, On-H-Ras regulated lymphocyte activation through both mRNA and protein level. Altogether, our results illustrated the involvement of H-Ras in teleost adaptive immunity via controlling lymphocyte activation, and thus provided a novel perspective to understand evolution of the lymphocyte-mediated adaptive immunity.
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Affiliation(s)
- Xiumei Wei
- State Key Laboratory of Estuarine and Coastal Research, Laboratory of Aquatic Comparative Immunology, School of Life Sciences, East China Normal University, Shanghai, 200241, China
| | - Tianyu Zhao
- State Key Laboratory of Estuarine and Coastal Research, Laboratory of Aquatic Comparative Immunology, School of Life Sciences, East China Normal University, Shanghai, 200241, China
| | - Yu Zhang
- State Key Laboratory of Estuarine and Coastal Research, Laboratory of Aquatic Comparative Immunology, School of Life Sciences, East China Normal University, Shanghai, 200241, China
| | - Kete Ai
- State Key Laboratory of Estuarine and Coastal Research, Laboratory of Aquatic Comparative Immunology, School of Life Sciences, East China Normal University, Shanghai, 200241, China
| | - Huiying Li
- State Key Laboratory of Estuarine and Coastal Research, Laboratory of Aquatic Comparative Immunology, School of Life Sciences, East China Normal University, Shanghai, 200241, China
| | - Jialong Yang
- State Key Laboratory of Estuarine and Coastal Research, Laboratory of Aquatic Comparative Immunology, School of Life Sciences, East China Normal University, Shanghai, 200241, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.
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Small GTPase RAS in multiple sclerosis - exploring the role of RAS GTPase in the etiology of multiple sclerosis. Small GTPases 2018; 11:312-319. [PMID: 30043672 DOI: 10.1080/21541248.2018.1502591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
Abstract
RAS signaling is involved in the development of autoimmunity in general. Multiple sclerosis (MS) is a T cell-mediated autoimmune disease of the central nervous system. It is widely recognized that a reduction of Foxp3+ regulatory T (Treg) cells is an immunological hallmark of MS, but the underlying mechanisms are unclear. In experimental autoimmune models, N-Ras and K-Ras inhibition triggers an anti-inflammatory effect up-regulating, via foxp3 elevation, the numbers and the functional suppressive properties of Tregs. Similarly, an increase in natural Tregs number during Experimental Autoimmune Encephalomyelitis (EAE) in R-RAS -/- mice results in attenuated disease. In humans, only KRAS GTPase isoform is involved in mechanism causing tolerance defects in rheumatoid arthritis (RA). T cells from these patients have increased transcription of KRAS (but not NRAS). RAS genes are major drivers in human cancers. Consequently, there has been considerable interest in developing anti-RAS inhibitors for cancer treatment. Despite efforts, no anti-RAS therapy has succeeded in the clinic. The major strategy that has so far reached the clinic aimed to inhibit activated Ras indirectly through blocking its post-translational modification and inducing its mis-localization. The disappointing clinical outcome of Farnesyl Transferase Inhibitors (FTIs) in cancers has decreased interest in these drugs. However, FTIs suppress EAE by downregulation of myelin-reactive activated T-lymphocytes and statins are currently studied in clinical trials for MS. However, no pharmacologic approaches to targeting Ras proteins directly have yet succeeded. The therapeutic strategy to recover immune function through the restoration of impaired Tregs function with the mounting evidences regarding KRAS in autoimmune mediated disorder (MS, SLE, RA, T1D) suggest as working hypothesis the direct targeting KRAS activation using cancer-derived small molecules may be clinically relevant. ABBREVIATIONS FTIs: Farnesyl Transferase Inhibitors; MS: Multiple Sclerosis; RRMS: Relapsing Remitting Multiple Sclerosis; PPMS: Primary Progressive Multiple Sclerosis; Tregs: regulatory T-cells; Foxp3: Forkhead box P3; EAE: Experimental Autoimmune Encephalomyelitis; T1D: Type 1 Diabete; SLE: Systemic Lupus Erythematosus; RA: Rheumatoid Arthritis; CNS: Central Nervous System; TMEV: Theiler's murine encephalomyelitis virus; FTS: farnesyl thiosalicylic acid; TCR: T-Cell Receptor; AIA: Adjuvant-induced Arthritis; EAN: experimental autoimmune neuritis; HVR: hypervariable region; HMG-CoA: 3-hydroxy-3-methylglutaryl coenzyme A reductase; PBMC: Peripheral Blood Mononuclear Cells.
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Mechanism of SOS PR-domain autoinhibition revealed by single-molecule assays on native protein from lysate. Nat Commun 2017; 8:15061. [PMID: 28452363 PMCID: PMC5414354 DOI: 10.1038/ncomms15061] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2016] [Accepted: 02/23/2017] [Indexed: 12/16/2022] Open
Abstract
The guanine nucleotide exchange factor (GEF) Son of Sevenless (SOS) plays a critical role in signal transduction by activating Ras. Here we introduce a single-molecule assay in which individual SOS molecules are captured from raw cell lysate using Ras-functionalized supported membrane microarrays. This enables characterization of the full-length SOS protein, which has not previously been studied in reconstitution due to difficulties in purification. Our measurements on the full-length protein reveal a distinct role of the C-terminal proline-rich (PR) domain to obstruct the engagement of allosteric Ras independently of the well-known N-terminal domain autoinhibition. This inhibitory role of the PR domain limits Grb2-independent recruitment of SOS to the membrane through binding of Ras·GTP in the SOS allosteric binding site. More generally, this assay strategy enables characterization of the functional behaviour of GEFs with single-molecule precision but without the need for purification.
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Li X, Ding Y, Zi M, Sun L, Zhang W, Chen S, Xu Y. CD19, from bench to bedside. Immunol Lett 2017; 183:86-95. [DOI: 10.1016/j.imlet.2017.01.010] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2016] [Revised: 01/19/2017] [Accepted: 01/20/2017] [Indexed: 12/27/2022]
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Cheng D, Deobagkar-Lele M, Zvezdova E, Choi S, Uehara S, Baup D, Bennett SC, Bull KR, Crockford TL, Ferry H, Warzecha C, Marcellin M, de Peredo AG, Lesourne R, Anzilotti C, Love PE, Cornall RJ. Themis2 lowers the threshold for B cell activation during positive selection. Nat Immunol 2016; 18:205-213. [PMID: 27992403 DOI: 10.1038/ni.3642] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Accepted: 11/22/2016] [Indexed: 12/21/2022]
Abstract
The positive and negative selection of lymphocytes by antigen is central to adaptive immunity and self-tolerance, yet how this is determined by different antigens is not completely understood. We found that thymocyte-selection-associated family member 2 (Themis2) increased the positive selection of B1 cells and germinal center B cells by self and foreign antigens. Themis2 lowered the threshold for B-cell activation by low-avidity, but not high-avidity, antigens. Themis2 constitutively bound the adaptor protein Grb2, src-kinase Lyn and signal transducer phospholipase γ2 (PLC-γ2), and increased activation of PLC-γ2 and its downstream pathways following B cell receptor stimulation. Our findings identify a unique function for Themis2 in differential signaling and provide insight into how B cells discriminate between antigens of different quantity and quality.
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Affiliation(s)
- Daian Cheng
- MRC Human Immunology Unit, Weatherall Institute for Molecular Medicine, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Mukta Deobagkar-Lele
- MRC Human Immunology Unit, Weatherall Institute for Molecular Medicine, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Ekaterina Zvezdova
- Section on Hematopoiesis and Lymphocyte Biology, Eunice Kennedy Shriver, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Seeyoung Choi
- Section on Hematopoiesis and Lymphocyte Biology, Eunice Kennedy Shriver, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Shoji Uehara
- Section on Hematopoiesis and Lymphocyte Biology, Eunice Kennedy Shriver, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Delphine Baup
- MRC Human Immunology Unit, Weatherall Institute for Molecular Medicine, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Sophia C Bennett
- MRC Human Immunology Unit, Weatherall Institute for Molecular Medicine, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Katherine R Bull
- MRC Human Immunology Unit, Weatherall Institute for Molecular Medicine, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Tanya L Crockford
- MRC Human Immunology Unit, Weatherall Institute for Molecular Medicine, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Helen Ferry
- MRC Human Immunology Unit, Weatherall Institute for Molecular Medicine, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Claude Warzecha
- Section on Hematopoiesis and Lymphocyte Biology, Eunice Kennedy Shriver, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Marlène Marcellin
- Institut de Pharmacologie et de Biologie Structurale and Université de Toulouse, Université Paul Sabatier, Centre National de la Recherche Scientifique, Toulouse, France
| | - Anne Gonzalez de Peredo
- Institut de Pharmacologie et de Biologie Structurale and Université de Toulouse, Université Paul Sabatier, Centre National de la Recherche Scientifique, Toulouse, France
| | - Renaud Lesourne
- Centre de Physiopathologie de Toulouse Purpan, Toulouse, France; and Institut National de la Santé et de la Recherche Médicale, U1043, Centre National de la Recherche Scientifique, and Université de Toulouse, Université Paul Sabatier, Toulouse, France
| | - Consuelo Anzilotti
- MRC Human Immunology Unit, Weatherall Institute for Molecular Medicine, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Paul E Love
- Section on Hematopoiesis and Lymphocyte Biology, Eunice Kennedy Shriver, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Richard J Cornall
- MRC Human Immunology Unit, Weatherall Institute for Molecular Medicine, Nuffield Department of Medicine, University of Oxford, Oxford, UK
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Christensen SM, Tu HL, Jun JE, Alvarez S, Triplet MG, Iwig JS, Yadav KK, Bar-Sagi D, Roose JP, Groves JT. One-way membrane trafficking of SOS in receptor-triggered Ras activation. Nat Struct Mol Biol 2016; 23:838-46. [PMID: 27501536 PMCID: PMC5016256 DOI: 10.1038/nsmb.3275] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Accepted: 07/08/2016] [Indexed: 02/07/2023]
Abstract
SOS is a key activator of the small GTPase Ras. In cells, SOS-Ras signaling is thought to be initiated predominantly by membrane recruitment of SOS via the adaptor Grb2 and balanced by rapidly reversible Grb2-SOS binding kinetics. However, SOS has multiple protein and lipid interactions that provide linkage to the membrane. In reconstituted-membrane experiments, these Grb2-independent interactions were sufficient to retain human SOS on the membrane for many minutes, during which a single SOS molecule could processively activate thousands of Ras molecules. These observations raised questions concerning how receptors maintain control of SOS in cells and how membrane-recruited SOS is ultimately released. We addressed these questions in quantitative assays of reconstituted SOS-deficient chicken B-cell signaling systems combined with single-molecule measurements in supported membranes. These studies revealed an essentially one-way trafficking process in which membrane-recruited SOS remains trapped on the membrane and continuously activates Ras until being actively removed via endocytosis.
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Affiliation(s)
- Sune M. Christensen
- Department of Chemistry, University of California, Berkeley, California, USA
| | - Hsiung-Lin Tu
- Department of Chemistry, University of California, Berkeley, California, USA
| | - Jesse E. Jun
- Department of Anatomy, University of California, San Francisco, California, USA
| | - Steven Alvarez
- Department of Chemistry, University of California, Berkeley, California, USA
| | - Meredith G. Triplet
- Department of Chemistry, University of California, Berkeley, California, USA
| | - Jeffrey S. Iwig
- Howard Hughes Medical Institute, Department of Molecular and Cell Biology, University of California, Berkeley, California, USA
| | - Kamlesh K. Yadav
- Department of Biochemistry, New York University School of Medicine, New York, USA
| | - Dafna Bar-Sagi
- Department of Biochemistry, New York University School of Medicine, New York, USA
| | - Jeroen P. Roose
- Department of Anatomy, University of California, San Francisco, California, USA
| | - Jay T. Groves
- Department of Chemistry, University of California, Berkeley, California, USA
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Golec DP, Henao Caviedes LM, Baldwin TA. RasGRP1 and RasGRP3 Are Required for Efficient Generation of Early Thymic Progenitors. THE JOURNAL OF IMMUNOLOGY 2016; 197:1743-53. [PMID: 27465532 DOI: 10.4049/jimmunol.1502107] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Accepted: 06/28/2016] [Indexed: 11/19/2022]
Abstract
T cell development is dependent on the migration of progenitor cells from the bone marrow to the thymus. Upon reaching the thymus, progenitors undergo a complex developmental program that requires inputs from various highly conserved signaling pathways including the Notch and Wnt pathways. To date, Ras signaling has not been implicated in the very earliest stages of T cell differentiation, but members of a family of Ras activators called RasGRPs have been shown to be involved at multiple stages of T cell development. We examined early T cell development in mice lacking RasGRP1, RasGRP3, and RasGRPs 1 and 3. We report that RasGRP1- and RasGRP3-deficient thymi show significantly reduced numbers of early thymic progenitors (ETPs) relative to wild type thymi. Furthermore, RasGRP1/3 double-deficient thymi show significant reductions in ETP numbers compared with either RasGRP1 or RasGRP3 single-deficient thymi, suggesting that both RasGRP1 and RasGRP3 regulate the generation of ETPs. In addition, competitive bone marrow chimera experiments reveal that RasGRP1/3 double-deficient progenitors intrinsically generate ETPs less efficiently than wild type progenitors. Finally, RasGRP1/3-deficient progenitors show impaired migration toward the CCR9 ligand, CCL25, suggesting that RasGRP1 and RasGRP3 may regulate progenitor entry into the thymus through a CCR9-dependent mechanism. These data demonstrate that, in addition to Notch and Wnt, the highly conserved Ras pathway is critical for the earliest stages of T cell development and further highlight the importance of Ras signaling during thymocyte maturation.
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Affiliation(s)
- Dominic P Golec
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta T6G 2S2, Canada
| | - Laura M Henao Caviedes
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta T6G 2S2, Canada
| | - Troy A Baldwin
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta T6G 2S2, Canada
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Hobeika E, Nielsen PJ, Medgyesi D. Signaling mechanisms regulating B-lymphocyte activation and tolerance. J Mol Med (Berl) 2015; 93:143-58. [PMID: 25627575 DOI: 10.1007/s00109-015-1252-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 12/15/2014] [Accepted: 12/25/2014] [Indexed: 01/01/2023]
Abstract
It is becoming more and more accepted that, in addition to producing autoantibodies, B lymphocytes have other important functions that influence the development of autoimmunity. For example, autoreactive B cells are able to produce inflammatory cytokines and activate pathogenic T cells. B lymphocytes can react to extracellular signals with a range of responses from anergy to autoreactivity. The final outcome is determined by the relative contribution of signaling events mediated by activating and inhibitory pathways. Besides the B cell antigen receptor (BCR), several costimulatory receptors expressed on B cells can also induce B cell proliferation and survival, or regulate antibody production. These include CD19, CD40, the B cell activating factor receptor, and Toll-like receptors. Hyperactivity of these receptors clearly contributes to breaking B-cell tolerance in several autoimmune diseases. Inhibitors of these activating signals (including protein tyrosine phosphatases, deubiquitinating enzymes and several adaptor proteins) are crucial to control B-cell activation and maintain B-cell tolerance. In this review, we summarize the inhibitory signaling mechanisms that counteract B-cell activation triggered by the BCR and the coreceptors.
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Affiliation(s)
- Elias Hobeika
- BIOSS Centre of Biological Signalling Studies, University of Freiburg and Department for Molecular Immunology, Faculty of Biology, University of Freiburg, 79104, Freiburg, Germany
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MAP Kinase Cascades in Antigen Receptor Signaling and Physiology. Curr Top Microbiol Immunol 2015; 393:211-231. [PMID: 26275875 DOI: 10.1007/82_2015_481] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Mitogen-activated protein kinases (MAPKs) play roles in a cell type and context-dependent manner to convert extracellular stimuli to a variety of cellular responses, thereby directing cells to proliferation, differentiation, survival, apoptosis, and migration. Studies of genetically engineered mice or chemical inhibitors specific to each MAPK signaling pathway revealed that MAPKs have various, but non-redundant physiologically important roles among different families. MAPK cascades are obviously integrated in the B cell receptor signaling pathways as critical components to drive B cell-mediated immunity.
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Azoulay-Alfaguter I, Strazza M, Mor A. Chaperone-mediated specificity in Ras and Rap signaling. Crit Rev Biochem Mol Biol 2014; 50:194-202. [PMID: 25488471 DOI: 10.3109/10409238.2014.989308] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Ras and Rap proteins are closely related small guanosine triphosphatase (GTPases) that share similar effector-binding domains but operate in a very different signaling networks; Ras has a dominant role in cell proliferation, while Rap mediates cell adhesion. Ras and Rap proteins are regulated by several shared processes such as post-translational modification, phosphorylation, activation by guanine exchange factors and inhibition by GTPase-activating proteins. Sub-cellular localization and trafficking of these proteins to and from the plasma membrane are additional important regulatory features that impact small GTPases function. Despite its importance, the trafficking mechanisms of Ras and Rap proteins are not completely understood. Chaperone proteins play a critical role in trafficking of GTPases and will be the focus of the discussion in this work. We will review several aspects of chaperone biology focusing on specificity toward particular members of the small GTPase family. Understanding this specificity should provide key insights into drug development targeting individual small GTPases.
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22
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Resolving Early Signaling Events in T-Cell Activation Leading to IL-2 and FOXP3 Transcription. Processes (Basel) 2014. [DOI: 10.3390/pr2040867] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Janardhan SV, Marks R, Gajewski TF. Primary murine CD4+ T cells fail to acquire the ability to produce effector cytokines when active Ras is present during Th1/Th2 differentiation. PLoS One 2014; 9:e112831. [PMID: 25397617 PMCID: PMC4232516 DOI: 10.1371/journal.pone.0112831] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Accepted: 10/16/2014] [Indexed: 01/10/2023] Open
Abstract
Constitutive Ras signaling has been shown to augment IL-2 production, reverse anergy, and functionally replace many aspects of CD28 co-stimulation in CD4+ T cells. These data raise the possibility that introduction of active Ras into primary T cells might result in improved functionality in pathologic situations of T cell dysfunction, such as cancer or chronic viral infection. To test the biologic effects of active Ras in primary T cells, CD4+ T cells from Coxsackie-Adenovirus Receptor Transgenic mice were transduced with an adenovirus encoding active Ras. As expected, active Ras augmented IL-2 production in naive CD4+ T cells. However, when cells were cultured for 4 days under conditions to promote effector cell differentiation, active Ras inhibited the ability of CD4+ T cells to acquire a Th1 or Th2 effector cytokine profile. This differentiation defect was not due to deficient STAT4 or STAT6 activation by IL-12 or IL-4, respectively, nor was it associated with deficient induction of T-bet and GATA-3 expression. Impaired effector cytokine production in active Ras-transduced cells was associated with deficient demethylation of the IL-4 gene locus. Our results indicate that, despite augmenting acute activation of naïve T cells, constitutive Ras signaling inhibits the ability of CD4+ T cells to properly differentiate into Th1/Th2 effector cytokine-producing cells, in part by interfering with epigenetic modification of effector gene loci. Alternative strategies to potentiate Ras pathway signaling in T cells in a more regulated fashion should be considered as a therapeutic approach to improve immune responses in vivo.
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Affiliation(s)
- Sujit V. Janardhan
- Department of Pathology, The University of Chicago, Chicago, Illinois, United States of America
| | - Reinhard Marks
- Department of Pathology, The University of Chicago, Chicago, Illinois, United States of America
| | - Thomas F. Gajewski
- Department of Pathology, The University of Chicago, Chicago, Illinois, United States of America
- Department of Medicine, The University of Chicago, Chicago, Illinois, United States of America
- * E-mail:
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Molecular mechanisms and functional implications of polarized actin remodeling at the T cell immunological synapse. Cell Mol Life Sci 2014; 72:537-556. [PMID: 25355055 DOI: 10.1007/s00018-014-1760-7] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Revised: 09/22/2014] [Accepted: 10/13/2014] [Indexed: 02/05/2023]
Abstract
Transient,specialized cell-cell interactions play a central role in leukocyte function by enabling specific intercellular communication in the context of a highly dynamic systems level response. The dramatic structural changes required for the formation of these contacts are driven by rapid and precise cytoskeletal remodeling events. In recent years, the immunological synapse that forms between a T lymphocyte and its antigen-presenting target cell has emerged as an important model system for understanding immune cell interactions. In this review, we discuss how regulators of the cortical actin cytoskeleton control synaptic architecture and in this way specify T cell function.
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Daley SR, Coakley KM, Hu DY, Randall KL, Jenne CN, Limnander A, Myers DR, Polakos NK, Enders A, Roots C, Balakishnan B, Miosge LA, Sjollema G, Bertram EM, Field MA, Shao Y, Andrews TD, Whittle B, Barnes SW, Walker JR, Cyster JG, Goodnow CC, Roose JP. Rasgrp1 mutation increases naive T-cell CD44 expression and drives mTOR-dependent accumulation of Helios⁺ T cells and autoantibodies. eLife 2013; 2:e01020. [PMID: 24336796 PMCID: PMC3858598 DOI: 10.7554/elife.01020] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Missense variants are a major source of human genetic variation. Here we analyze a new mouse missense variant, Rasgrp1Anaef, with an ENU-mutated EF hand in the Rasgrp1 Ras guanine nucleotide exchange factor. Rasgrp1Anaef mice exhibit anti-nuclear autoantibodies and gradually accumulate a CD44hi Helios+ PD-1+ CD4+ T cell population that is dependent on B cells. Despite reduced Rasgrp1-Ras-ERK activation in vitro, thymocyte selection in Rasgrp1Anaef is mostly normal in vivo, although CD44 is overexpressed on naïve thymocytes and T cells in a T-cell-autonomous manner. We identify CD44 expression as a sensitive reporter of tonic mTOR-S6 kinase signaling through a novel mouse strain, chino, with a reduction-of-function mutation in Mtor. Elevated tonic mTOR-S6 signaling occurs in Rasgrp1Anaef naïve CD4+ T cells. CD44 expression, CD4+ T cell subset ratios and serum autoantibodies all returned to normal in Rasgrp1AnaefMtorchino double-mutant mice, demonstrating that increased mTOR activity is essential for the Rasgrp1Anaef T cell dysregulation. DOI:http://dx.doi.org/10.7554/eLife.01020.001 Our DNA contains more than three billion nucleotides. Each of these nucleotides can be an A, C, G or T, and groups of three neighboring nucleotides within our DNA are used to represent the 20 amino acids that are used to make proteins. This means that changing just one nucleotide can cause one amino acid to be replaced by a different amino acid in the protein encoded by that stretch of DNA: AAA and AAG code for the amino acid lysine, for example, but AAC and AAT code for asparagine. Known as missense gene variants, these changes can also increase or decrease the expression of the gene. Every person has thousands of missense gene variants, including about 12,000 inherited from their parents. Sometimes these variants have no consequence, but they can be harmful if replacing the correct amino acid with a different amino acid prevents the protein from performing an important task. In particular, missense gene variants in genes that encode immune system proteins are likely to play a role in diseases of the immune system. For example, variants near a gene called Rasgrp1 have been linked to two autoimmune diseases – type 1 diabetes and Graves’ disease—in which the immune system mistakenly attacks the body’s own cells and tissues. Now Daley et al. have shed new light on the mechanism by which a missense gene variant in Rasgrp1 can cause autoimmune diseases. Mice with this mutation show signs of autoimmune disease, but their T cells—white blood cells that have a central role in the immune system – develop normally despite this mutation. Instead, Daley et al. found that a specific type of T cell, called T helper cells, accumulated in large numbers in the mutant mice and stimulated cells of a third type—immune cells called B cells—to produce autoantibodies. The production of autoantibodies is a common feature of autoimmune diseases. Daley et al. traced the origins of the T helper cells to excessive activity on a signaling pathway that involves a protein called mTOR, and went on to show that treatment with the drug rapamycin counteracted the accumulation of the T helper cells and reduced the level of autoimmune activity. In addition to exemplifying how changing just one amino acid change can have a profound effect, the work of Daley et al. is an attractive model for exploring how missense gene variants in people can contribute to autoimmune diseases. DOI:http://dx.doi.org/10.7554/eLife.01020.002
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Affiliation(s)
- Stephen R Daley
- Department of Immunology, John Curtin School of Medical Research, The Australian National University, Canberra, Australia
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Le Floc'h A, Tanaka Y, Bantilan NS, Voisinne G, Altan-Bonnet G, Fukui Y, Huse M. Annular PIP3 accumulation controls actin architecture and modulates cytotoxicity at the immunological synapse. ACTA ACUST UNITED AC 2013; 210:2721-37. [PMID: 24190432 PMCID: PMC3832928 DOI: 10.1084/jem.20131324] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
In T cells, PI3K activation in the periphery of the immune synapse leads to PIP3 accumulation that promotes actin polymerization in a pathway important for cytotoxic function. The immunological synapse formed by a T lymphocyte on the surface of a target cell contains a peripheral ring of filamentous actin (F-actin) that promotes adhesion and facilitates the directional secretion of cytokines and cytolytic factors. We show that growth and maintenance of this F-actin ring is dictated by the annular accumulation of phosphatidylinositol trisphosphate (PIP3) in the synaptic membrane. PIP3 functions in this context by recruiting the exchange factor Dock2 to the periphery of the synapse, where it drives actin polymerization through the Rho-family GTPase Rac. We also show that synaptic PIP3 is generated by class IA phosphoinositide 3-kinases that associate with T cell receptor microclusters and are activated by the GTPase Ras. Perturbations that inhibit or promote PIP3-dependent F-actin remodeling dramatically affect T cell cytotoxicity, demonstrating the functional importance of this pathway. These results reveal how T cells use lipid-based signaling to control synaptic architecture and modulate effector responses.
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Affiliation(s)
- Audrey Le Floc'h
- Immunology Program, 2 Computational Biology Program, Memorial Sloan-Kettering Cancer Center, New York, NY 10065
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Oliver JA, Lapinski PE, Lubeck BA, Turner JS, Parada LF, Zhu Y, King PD. The Ras GTPase-activating protein neurofibromin 1 promotes the positive selection of thymocytes. Mol Immunol 2013; 55:292-302. [PMID: 23522726 PMCID: PMC3646930 DOI: 10.1016/j.molimm.2013.03.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2012] [Revised: 02/27/2013] [Accepted: 03/04/2013] [Indexed: 02/08/2023]
Abstract
TCR-mediated activation of the Ras signaling pathway is critical for T cell development in the thymus and function in the periphery. However, which members of a family of Ras GTPase-activating proteins (RasGAPs) negatively regulate Ras activation in T cells is unknown. In this study we examined a potential function for the neurofibromin 1 (NF1) RasGAP in the T cell lineage with the use of T cell-specific NF1-deficient mice. Surprisingly, on an MHC class I-restricted TCR transgenic background, NF1 was found to promote thymocyte positive selection. By contrast, NF1 neither promoted nor inhibited the negative selection of thymocytes. In the periphery, NF1 was found to be necessary for the maintenance of normal numbers of naïve CD4⁺ and CD8⁺ T cells but was dispensable as a regulator of TCR-induced Ras activation, cytokine synthesis, proliferation and differentiation and death. These findings point to a novel unexpected role for NF1 in T cell development as well as a regulator of T cell homeostasis.
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Affiliation(s)
- Jennifer A. Oliver
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Philip E. Lapinski
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Beth A. Lubeck
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Jackson S. Turner
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Luis F. Parada
- Department of Developmental Biology, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
| | - Yuan Zhu
- Division of Molecular Medicine and Genetics, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Philip D. King
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
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Activation of Extracellular Signal-Regulated Kinase but Not of p38 Mitogen-Activated Protein Kinase Pathways in Lymphocytes Requires Allosteric Activation of SOS. Mol Cell Biol 2013; 33:2470-84. [DOI: 10.1128/mcb.01593-12] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
ABSTRACT
Thymocytes convert graded T cell receptor (TCR) signals into positive selection or deletion, and activation of extracellular signal-related kinase (ERK), p38, and Jun N-terminal protein kinase (JNK) mitogen-activated protein kinases (MAPKs) has been postulated to play a discriminatory role. Two families of Ras guanine nucleotide exchange factors (RasGEFs), SOS and RasGRP, activate Ras and the downstream RAF-MEK-ERK pathway. The pathways leading to lymphocyte p38 and JNK activation are less well defined. We previously described how RasGRP alone induces analog Ras-ERK activation while SOS and RasGRP cooperate to establish bimodal ERK activation. Here we employed computational modeling and biochemical experiments with model cell lines and thymocytes to show that TCR-induced ERK activation grows exponentially in thymocytes and that a W729E allosteric pocket mutant, SOS1, can only reconstitute analog ERK signaling. In agreement with RasGRP allosterically priming SOS, exponential ERK activation is severely decreased by pharmacological or genetic perturbation of the phospholipase Cγ (PLCγ)-diacylglycerol-RasGRP1 pathway. In contrast, p38 activation is not sharply thresholded and requires high-level TCR signal input. Rac and p38 activation depends on SOS1 expression but not allosteric activation. Based on computational predictions and experiments exploring whether SOS functions as a RacGEF or adaptor in Rac-p38 activation, we established that the presence of SOS1, but not its enzymatic activity, is critical for p38 activation.
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Kong G, Du J, Liu Y, Meline B, Chang YI, Ranheim EA, Wang J, Zhang J. Notch1 gene mutations target KRAS G12D-expressing CD8+ cells and contribute to their leukemogenic transformation. J Biol Chem 2013; 288:18219-27. [PMID: 23673656 DOI: 10.1074/jbc.m113.475376] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Acute T-cell lymphoblastic leukemia/lymphoma (T-ALL) is an aggressive hematopoietic malignancy affecting both children and adults. Previous studies of T-ALL mouse models induced by different genetic mutations have provided highly diverse results on the issues of T-cell leukemia/lymphoma-initiating cells (T-LICs) and potential mechanisms contributing to T-LIC transformation. Here, we show that oncogenic Kras (Kras G12D) expressed from its endogenous locus is a potent inducer of T-ALL even in a less sensitized BALB/c background. Notch1 mutations, including exon 34 mutations and recently characterized type 1 and 2 deletions, are detected in 100% of Kras G12D-induced T-ALL tumors. Although these mutations are not detected at the pre-leukemia stage, incremental up-regulation of NOTCH1 surface expression is observed at the pre-leukemia and leukemia stages. As secondary genetic hits in the Kras G12D model, Notch1 mutations target CD8(+) T-cells but not hematopoietic stem cells to further promote T-ALL progression. Pre-leukemia T-cells without detectable Notch1 mutations do not induce T-ALL in secondary recipient mice compared with T-ALL tumor cells with Notch1 mutations. We found huge variations in T-LIC frequency and immunophenotypes of cells enriched for T-LICs. Unlike Pten deficiency-induced T-ALL, oncogenic Kras-initiated T-ALL is not associated with up-regulation of the Wnt/β-catenin pathway. Our results suggest that up-regulation of NOTCH1 signaling, through either overexpression of surface NOTCH1 or acquired gain-of-function mutations, is involved in both T-ALL initiation and progression. Notch1 mutations and Kras G12D contribute cooperatively to leukemogenic transformation of normal T-cells.
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Affiliation(s)
- Guangyao Kong
- McArdle Laboratory for Cancer Research, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
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31
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Muscolini M, Camperio C, Capuano C, Caristi S, Piccolella E, Galandrini R, Tuosto L. Phosphatidylinositol 4-Phosphate 5-Kinase α Activation Critically Contributes to CD28-Dependent Signaling Responses. THE JOURNAL OF IMMUNOLOGY 2013; 190:5279-86. [DOI: 10.4049/jimmunol.1203157] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Abstract
Activating mutations and overexpression of classical Ras subfamily members (K-Ras, N-Ras and H-Ras) have been widely investigated as key events in the development of human cancers. The role in cancer of its closest relatives, the Ras-related (RRas) subfamily members, has been less studied despite the fact that one of its members (TC21 or RRas2) is strongly transforming in vitro. Nevertheless, and in spite the paucity of publications, several studies have shown that wild type TC21 is overexpressed in different types of carcinomas and lymphomas. If the study of RRas members in cancer is still in its infancy, their role in physiological functions is even behind. For instance, T and B cell immunologists still use the vague term "Ras activation" without indication of what Ras family molecule is indeed intervening. In this view, we discuss the participation of TC21 in the specific process of T cell antigen receptor internalization from the immunological synapse and acquisition of membrane fragments from the antigen presenting cells by phagocytosis.
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Affiliation(s)
- Balbino Alarcón
- Centro de Biologia Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas, Universidad Autonoma de Madrid, Madrid, Spain.
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Dillon TJ, Takahashi M, Li Y, Tavisala S, Murray SE, Moran AE, Parker DC, Stork PJS. B-Raf is required for positive selection and survival of DP cells, but not for negative selection of SP cells. Int Immunol 2013; 25:259-69. [PMID: 23334952 DOI: 10.1093/intimm/dxs104] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The duration of signaling through the MAP kinase (or ERK pathway) cascade has been implicated in thymic development, particularly positive and negative selection. In T cells, two isoforms of the MAP kinase kinase kinase Raf function to transmit signals from the T-cell receptor to ERK: C-Raf and B-Raf. In this study, we conditionally ablated B-Raf expression within thymocytes to assess the effects on ERK activation and thymocyte development. The complete loss of B-Raf is accompanied by a dramatic loss of ERK activation in both the double positive (DP) and single positive (SP) thymocytes, as well as peripheral splenocytes. There was a significant decrease in the cellularity of KO thymi, largely due to a loss of pre-selected DP cells, a decrease in DP cells undergoing positive selection, and a defect in SP maturation. B-Raf plays significant roles in survival of DP thymocytes and function of SP cells in the periphery. Surprisingly, we saw no effect of B-Raf deficiency on negative selection of autoreactive SP thymocytes, despite the greatly reduced ERK activation in these cells.
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Affiliation(s)
- Tara J Dillon
- Vollum Institute, Oregon Health and Science University, Portland, OR, USA
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Kortum RL, Rouquette-Jazdanian AK, Miyaji M, Merrill RK, Markegard E, Pinski JM, Wesselink A, Nath NN, Alexander CP, Li W, Kedei N, Roose JP, Blumberg PM, Samelson LE, Sommers CL. A phospholipase C-γ1-independent, RasGRP1-ERK-dependent pathway drives lymphoproliferative disease in linker for activation of T cells-Y136F mutant mice. THE JOURNAL OF IMMUNOLOGY 2012; 190:147-58. [PMID: 23209318 DOI: 10.4049/jimmunol.1201458] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Mice expressing a germline mutation in the phospholipase C-γ1-binding site of linker for activation of T cells (LAT) show progressive lymphoproliferation and ultimately die at 4-6 mo age. The hyperactivated T cells in these mice show defective TCR-induced calcium flux but enhanced Ras/ERK activation, which is critical for disease progression. Despite the loss of LAT-dependent phospholipase C-γ1 binding and activation, genetic analysis revealed RasGRP1, and not Sos1 or Sos2, to be the major Ras guanine exchange factor responsible for ERK activation and the lymphoproliferative phenotype in these mice. Analysis of isolated CD4(+) T cells from LAT-Y136F mice showed altered proximal TCR-dependent kinase signaling, which activated a Zap70- and LAT-independent pathway. Moreover, LAT-Y136F T cells showed ERK activation that was dependent on Lck and/or Fyn, protein kinase C-θ, and RasGRP1. These data demonstrate a novel route to Ras activation in vivo in a pathological setting.
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Affiliation(s)
- Robert L Kortum
- Laboratory of Cellular and Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
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Huang H, Jin T, Wang L, Wang F, Zhang R, Pan Y, Wang Z, Chen Y. The RAS guanyl nucleotide-releasing protein RasGRP1 is involved in lymphatic development in zebrafish. J Biol Chem 2012. [PMID: 23184941 DOI: 10.1074/jbc.m112.418202] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The molecular basis of the lymphatic development remains largely unknown. Using zebrafish as a model, we discovered a novel role for the Ras guanine-releasing protein 1 (RasGRP1), a protein involved in Ras activation in lymphangiogenesis. Secondary lymphatic sprouts from the posterior cardinal vein give rise to thoracic duct which is the first lymphatic vessel in zebrafish. Knockdown of rasgrp1 by injecting morpholino in zebrafish embryos impaired formation of thoracic duct accompanied by pericardial and truck edema, whereas blood vessel development of the embryos was largely unaffected. In rasgrp1-knockdown embryos, the number of sprouts producing the string of parachordal lymphangioblast cells was reduced. Meanwhile the total number of the secondary sprouts was not changed. As a result, the number of venous intersegmental vessels was increased, whereas the number of lymphatic vessel was reduced at a later stage. The lymphatic developmental defects caused by rasgrp1 knockdown could be rescued by ectopic expression of a constitutively active HRas. Further analysis revealed that RasGRP1 knockdown could synergize with flt4/vegfr3 knockdown to induce defects in lymphangiogenesis. Taken together, this finding demonstrates a critical role for RasGRP1 in lymphatic development in zebrafish.
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Affiliation(s)
- Heng Huang
- Key Laboratory of Nutrition and Metabolism, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China
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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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Reedquist KA, Tak PP. Signal transduction pathways in chronic inflammatory autoimmune disease: small GTPases. Open Rheumatol J 2012; 6:259-72. [PMID: 23028410 PMCID: PMC3460313 DOI: 10.2174/1874312901206010259] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2011] [Revised: 06/19/2012] [Accepted: 06/21/2012] [Indexed: 01/28/2023] Open
Abstract
Ras superfamily small GTPases represent a wide and diverse class of intracellular signaling proteins that are highly conserved during evolution. These enzymes serve as key checkpoints in coupling antigen receptor, growth factor, cytokine and chemokine stimulation to cellular responses. Once activated, via their ability to regulate multiple downstream signaling pathways, small GTPases amplify and diversify signaling cascades which regulate cellular proliferation, survival, cytokine expression, trafficking and retention. Small GTPases, particularly members of the Ras, Rap, and Rho family, critically coordinate the function and interplay of immune and stromal cells during inflammatory respones, and increasing evidence indicates that alterations in small GTPase signaling contribute to the pathological behavior of these cell populations in human chronic inflammatory diseases such as rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE). Here, we review how Ras, Rap, and Rho family GTPases contribute to the biology of cell populations relevant to human chronic inflammatory disease, highlight recent advances in understanding how alterations in these pathways contribute to pathology in RA and SLE, and discuss new therapeutic strategies that may allow specific targeting of small GTPases in the clinic.
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Affiliation(s)
- Kris A Reedquist
- Division of Clinical Immunology and Rheumatology, Department of Experimental Immunology, Academic Medical Center, University of Amsterdam, The Netherlands
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Mageed RA, Garaud S, Taher TE, Parikh K, Pers JO, Jamin C, Renaudineau Y, Youinou P. CD5 expression promotes multiple intracellular signaling pathways in B lymphocyte. Autoimmun Rev 2012; 11:795-8. [DOI: 10.1016/j.autrev.2012.02.007] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Colasanti T, Maselli A, Conti F, Sanchez M, Alessandri C, Barbati C, Vacirca D, Tinari A, Chiarotti F, Giovannetti A, Franconi F, Valesini G, Malorni W, Pierdominici M, Ortona E. Autoantibodies to estrogen receptor α interfere with T lymphocyte homeostasis and are associated with disease activity in systemic lupus erythematosus. ACTA ACUST UNITED AC 2012; 64:778-87. [PMID: 21968947 DOI: 10.1002/art.33400] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
OBJECTIVE Estrogens influence many physiologic processes and are also implicated in the development or progression of numerous diseases, including autoimmune disorders. Aberrations of lymphocyte homeostasis that lead to the production of multiple pathogenic autoantibodies, including autoantibodies specific to estrogen receptor (ER), have been detected in the peripheral blood of patients with systemic lupus erythematosus (SLE). This study was undertaken to assess the presence of both anti-ERα and anti-ERβ antibodies in sera from patients with SLE, to analyze the effect of these antibodies on peripheral blood T lymphocyte homeostasis, and to evaluate their role as determinants of disease pathogenesis and progression. METHODS Anti-ER antibody serum immunoreactivity was analyzed by enzyme-linked immunosorbent assay in samples from 86 patients with SLE and 95 healthy donors. Phenotypic and functional analyses were performed by flow cytometry and Western blotting. RESULTS Anti-ERα antibodies were present in 45% of the patients with SLE, whereas anti-ERβ antibodies were undetectable. In healthy donors, anti-ERα antibodies induced cell activation and consequent apoptotic cell death in resting lymphocytes as well as proliferation of anti-CD3-stimulated T lymphocytes. A significant association between anti-ERα antibody values and clinical parameters, i.e., the SLE Disease Activity Index and arthritis, was found. CONCLUSION Our data suggest that anti-ERα autoantibodies interfere with T lymphocyte homeostasis and are significantly associated with lupus disease activity.
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Affiliation(s)
- Tania Colasanti
- Istituto Superiore di Sanità, Rome, Italy, and San Raffaele Institute Sulmona, L'Aquila, Italy
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Sustained Rap1 activation in autoantigen-specific T lymphocytes attenuates experimental autoimmune encephalomyelitis. J Neuroimmunol 2012; 250:35-43. [PMID: 22688423 DOI: 10.1016/j.jneuroim.2012.05.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Revised: 05/14/2012] [Accepted: 05/18/2012] [Indexed: 11/21/2022]
Abstract
Altered Ras superfamily guanine nucleotide triphosphatase signaling may contribute to the activation of autoreactive T cells in diseases such as rheumatoid arthritis and systemic lupus erythematosus. Here, we show that transgenic expression of activated Rap1, a Ras-related protein which is protective in murine arthritis, in both wildtype (WT) and 2D2 mice, enhances autoreactive T cell activation by myelin oligodendrocyte glycoprotein peptide in vitro and in vivo. However, RapV12 reduces the number of autoreactive T cells in both WT and 2D2 mice, and increases murine survival in experimental autoimmune encephalitis, suggesting Rap1 activation restricts autoimmune T cell-mediated pathology through enhancing tolerance.
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Abel SM, Roose JP, Groves JT, Weiss A, Chakraborty AK. The membrane environment can promote or suppress bistability in cell signaling networks. J Phys Chem B 2012; 116:3630-40. [PMID: 22332778 DOI: 10.1021/jp2102385] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Many key biochemical reactions that mediate signal transduction in cells occur at the cell membrane, yet how the two-dimensional membrane environment influences the collective behavior of signaling networks is poorly understood. We study models of two topologically different signaling pathways that exhibit bistability, examining the effects of reduced protein mobility and increased concentration at the membrane, as well as effects due to differences in spatiotemporal correlations between the membrane environment and three-dimensional cytoplasm. The two model networks represent the distributive enzymatic modification of a protein at multiple sites and the positive feedback-mediated activation of a protein. In both cases, we find that confining proteins to a membrane-like environment can markedly alter the emergent dynamics. For the distributive protein modification network, increased concentration promotes bistability through enhanced protein-protein binding, while lower mobility and membrane-enhanced spatiotemporal correlations suppress bistability. For the positive feedback-mediated activation network, confinement to a membrane environment enhances protein activation, which can induce bistability or stabilize a monostable, active state. Importantly, the influence of the membrane environment on signaling dynamics can be qualitatively different for signaling modules with different network topologies.
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Affiliation(s)
- Steven M Abel
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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Semplice M, Veglio A, Naldi G, Serini G, Gamba A. A bistable model of cell polarity. PLoS One 2012; 7:e30977. [PMID: 22383986 PMCID: PMC3285628 DOI: 10.1371/journal.pone.0030977] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2011] [Accepted: 12/29/2011] [Indexed: 12/16/2022] Open
Abstract
Ultrasensitivity, as described by Goldbeter and Koshland, has been considered for a long time as a way to realize bistable switches in biological systems. It is not as well recognized that when ultrasensitivity and reinforcing feedback loops are present in a spatially distributed system such as the cell plasmamembrane, they may induce bistability and spatial separation of the system into distinct signaling phases. Here we suggest that bistability of ultrasensitive signaling pathways in a diffusive environment provides a basic mechanism to realize cell membrane polarity. Cell membrane polarization is a fundamental process implicated in several basic biological phenomena, such as differentiation, proliferation, migration and morphogenesis of unicellular and multicellular organisms. We describe a simple, solvable model of cell membrane polarization based on the coupling of membrane diffusion with bistable enzymatic dynamics. The model can reproduce a broad range of symmetry-breaking events, such as those observed in eukaryotic directional sensing, the apico-basal polarization of epithelium cells, the polarization of budding and mating yeast, and the formation of Ras nanoclusters in several cell types.
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Affiliation(s)
- Matteo Semplice
- Department of Physics and Mathematics, Università dell'Insubria, Como, Italy
| | - Andrea Veglio
- Genomes and Genetics Department, Unit Physics of Biological Systems, Institut Pasteur, Paris, France
| | - Giovanni Naldi
- Department of Mathematics “F. Enriques”, Università degli studi di Milano, Milano, Italy
- * E-mail:
| | - Guido Serini
- Laboratory of Cell Adhesion Dynamics, Institute for Cancer Research and Treatment and Department of Oncological Sciences, School of Medicine, Università degli studi di Torino, Candiolo, Italy
| | - Andrea Gamba
- Department of Mathematics, Politecnico di Torino, Torino, Italy
- Laboratory of Systems Biology, Institute for Cancer Research and Treatment, Candiolo, Italy
- INFN, Torino, Italy
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Prevention of induced colitis in mice by the ras antagonist farnesylthiosalicylic acid. Dig Dis Sci 2012; 57:320-6. [PMID: 21901261 DOI: 10.1007/s10620-011-1880-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2011] [Accepted: 08/16/2011] [Indexed: 02/06/2023]
Abstract
BACKGROUND Ras proteins are crucial for cell differentiation and proliferation. Targeting Ras with farnesylthiosalicylic acid (FTS), a Ras antagonist, has been suggested as a therapeutic strategy in proliferative and inflammatory diseases. AIMS To examine the role of Ras and the therapeutic potential of FTS in experimental colitis. METHODS Colitis was induced in 26 mice by adding 2.5% dextran sodium sulfate to their drinking water for 7 days during which 12 study mice were treated with FTS and 14 control mice were given normal saline. Two additional controls included 10 naïve mice treated with FTS and 7 naïve non-treated mice. The animals were followed clinically and sacrificed after 7 days. Their colons were isolated for histological assessment and for measurement of myeloperoxidase activity (MPO), tumor necrosis factor-α(TNF-α), and interleukin-1β(Il-1β) levels. Ras and activated Ras expression was determined by immunoblotting assays. T cell populations in the colon and spleen were analyzed by flow-cytometry. RESULTS FTS induced a 2.1-fold reduction in activated Ras levels (P < 0.004). FTS-treated mice had lower disease activity scores (3.9 ± 1.7 vs. 7.5 ± 2.3, P < 0.001), and lower levels of MPO activity (1.65 ± 0.6 vs. 2.6 ± 0.8 units/g, P < 0.007), Il-1β (2.4 ± 3.6 vs. 24.3 ± 17.5 pg/mg, P < 0.01) and TNF-α (0.63 ± 0.5 vs. 1.9 ± 1 pg/mg, P < 0.04). FTS increased regulatory T cell population in the spleen (1.9 ± 0.4-fold, P < 0.04), and decreased effector T cell populations in the colon and spleen by 24 ± 3% (P < 0.03) and 27 ± 1% (P < 0.02), respectively. FTS had no remarkable side effects. CONCLUSIONS Ras is involved in the inflammatory processes of induced colitis in mice and its inhibition by FTS ameliorates the severity of the inflammation.
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Szabo M, Czompoly T, Kvell K, Talaber G, Bartis D, Nemeth P, Berki T, Boldizsar F. Fine-tuning of proximal TCR signaling by ZAP-70 tyrosine residues in Jurkat cells. Int Immunol 2011; 24:79-87. [PMID: 22207134 DOI: 10.1093/intimm/dxr105] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Zeta-chain-associated protein kinase of 70kDa (ZAP-70) kinase is a key regulator in the early steps of TCR signaling but some aspects of its fine regulation are still unclear. From its 31 tyrosine (Y) residues, 11 phosphorylation sites have been identified, some with activator (Y315 and Y493) or inhibitory (Y292 and Y492) and others with unknown function (Y069, Y126 and Y178). In our present work, we aimed to elucidate the role of different Y residues of ZAP-70, especially those with unknown function, in calcium signaling and the autoregulation of the kinase. ZAP-70-deficient Jurkat cells (P116) were stably reconstituted with point-mutated ZAP-70 constructs where tyrosine residues 069, 126, 178, 238, 292, 315, 492 or 493 were replaced with phenylalanine (F). The anti-CD3-elicited calcium signal increased in F069-, F292- and F492-ZAP-70-expressing cell lines but decreased in the F126-, F315- and F493-ZAP-70-expressing cell lines. ZAP-70 point mutations led to phosphorylation changes predominantly in SH2 domain containing leukocyte protein of 76kDa (SLP-76) but not linker of activated T cells (LAT) during CD3-activation; moreover, we detected basal hyperphosphorylation of SLP-76 Y128 in the F126-, F178- and F492-ZAP-70-expressing cell lines. In summary, Y069, Y178, Y292 and Y492 have inhibitory, while Y126, Y315 and Y493 activator role in anti-CD3-induced T-cell activation. Phosphorylation changes in LAT and SLP-76 suggest that fine regulation of ZAP-70 on calcium signaling is rather transmitted through SLP-76 not LAT. Additionally, negative or positive autoregulatory function of Y292 and Y493 or Y315, respectively, was revealed in ZAP-70. These data indicate that previously not characterized Y069, Y126 and Y178 in ZAP-70 participate in the fine regulation of TCR signaling.
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Affiliation(s)
- M Szabo
- Department of Immunology and Biotechnology, University of Pecs, H-7643 Pecs, Hungary
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45
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Janas ML, Turner M. Interaction of Ras with p110γ is required for thymic β-selection in the mouse. THE JOURNAL OF IMMUNOLOGY 2011; 187:4667-75. [PMID: 21930962 DOI: 10.4049/jimmunol.1101949] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Thymocytes are tested for productive rearrangement of the tcrb locus by expression of a pre-TCR in a process termed β-selection, which requires both Notch1 and CXCR4 signaling. It has been shown that activation of the GTPase Ras allows thymocytes to proliferate and differentiate in the absence of a Pre-TCR; the direct targets of Ras at this checkpoint have not been identified, however. Mice with a mutant allele of p110γ unable to bind active Ras revealed that CXCR4-mediated PI3K activation is Ras dependent. The Ras-p110γ interaction was necessary for efficient β-selection-promoted proliferation but was dispensable for the survival or differentiation of thymocytes. Uncoupling Ras from p110γ provides unambiguous identification of a Ras interaction required for thymic β-selection.
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Affiliation(s)
- Michelle L Janas
- Laboratory of Lymphocyte Signalling and Development, The Babraham Institute, Cambridge CB22 3AT, United Kingdom
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46
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Limnander A, Weiss A. Ca-dependent Ras/Erk signaling mediates negative selection of autoreactive B cells. Small GTPases 2011; 2:282-288. [PMID: 22292132 DOI: 10.4161/sgtp.2.5.17794] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2011] [Revised: 08/08/2011] [Accepted: 08/18/2011] [Indexed: 12/17/2022] Open
Abstract
Signaling via the Ras/Erk pathway has long been recognized to be critical in lymphocyte development and function, yet the mechanisms that control the distinct functional outputs of this pathway in different cellular contexts remain poorly understood. Our recent results have demonstrated unexpected involvement of Ras/Erk signaling in the sensitization of B cells to apoptosis in order to eliminate autoreactive cells. Increases in cytosolic Ca(2+) are necessary and sufficient to induce activation of this Ras/Erk pathway, and the biochemical events involved in its activation are different from the ones involved in diacylglycerol (DAG)-mediated Ras/Erk activation. Developmental regulation of upstream mediators of these distinct pathways contributes to their predominant activation at different stages of B cell development. These findings have revealed a mechanism by which antigen stimulation can activate distinct Ras/Erk pathways at different developmental stages to mediate appropriate functional outputs that control the selection, development and activation of B cells. Despite these recent findings, however, much remains to be learned about the molecular mechanisms that confer functional specificity to common Ras/Erk signaling modules.
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Affiliation(s)
- Andre Limnander
- Department of Medicine; Howard Hughes Medical Institute; Rosalind Russell Medical Research Center for Arthritis; University of California at San Francisco; San Francisco, CA USA
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Mor A, Aizman E, George J, Kloog Y. Ras inhibition induces insulin sensitivity and glucose uptake. PLoS One 2011; 6:e21712. [PMID: 21738773 PMCID: PMC3126849 DOI: 10.1371/journal.pone.0021712] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2011] [Accepted: 06/06/2011] [Indexed: 02/06/2023] Open
Abstract
Background Reduced glucose uptake due to insulin resistance is a pivotal mechanism in the pathogenesis of type 2 diabetes. It is also associated with increased inflammation. Ras inhibition downregulates inflammation in various experimental models. The aim of this study was to examine the effect of Ras inhibition on insulin sensitivity and glucose uptake, as well as its influence on type 2 diabetes development. Methods and Findings The effect of Ras inhibition on glucose uptake was examined both in vitro and in vivo. Ras was inhibited in cells transfected with a dominant-negative form of Ras or by 5-fluoro-farnesylthiosalicylic acid (F-FTS), a small-molecule Ras inhibitor. The involvement of IκB and NF-κB in Ras-inhibited glucose uptake was investigated by immunoblotting. High fat (HF)-induced diabetic mice were treated with F-FTS to test the effect of Ras inhibition on induction of hyperglycemia. Each of the Ras-inhibitory modes resulted in increased glucose uptake, whether in insulin-resistant C2C12 myotubes in vitro or in HF-induced diabetic mice in vivo. Ras inhibition also caused increased IκB expression accompanied by decreased expression of NF-κB . In fat-induced diabetic mice treated daily with F-FTS, both the incidence of hyperglycemia and the levels of serum insulin were significantly decreased. Conclusions Inhibition of Ras apparently induces a state of heightened insulin sensitization both in vitro and in vivo. Ras inhibition should therefore be considered as an approach worth testing for the treatment of type 2 diabetes.
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Affiliation(s)
- Adi Mor
- Department of Neurobiology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel-Aviv, Israel
| | - Elizabeta Aizman
- Department of Neurobiology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel-Aviv, Israel
| | - Jacob George
- Department of Cardiology, Kaplan Medical Center, Rehovot, affiliated to the Hebrew University—Hadassah Medical School, Jerusalem, Israel
| | - Yoel Kloog
- Department of Neurobiology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel-Aviv, Israel
- * E-mail:
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H-ras and N-ras are dispensable for T-cell development and activation but critical for protective Th1 immunity. Blood 2011; 117:5102-11. [PMID: 21444916 DOI: 10.1182/blood-2010-10-315770] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The small guanine nucleotide binding proteins of the Ras family, including in mammals the highly homologous H-ras, N-ras, and K-ras isoforms, are rapidly activated on ligation of the T-cell antigen receptor (TCR), but whether each isoform plays specific roles in T cells is largely unknown. Here, we show, with the use of mice specifically lacking H-ras or N-ras, that these isoforms are dispensable for thymocyte development and mature T-cell activation. By contrast, CD4⁺ T cells from Ras-deficient mice exhibited markedly decreased production of the Th1 signature cytokine IFN-γ early after TCR stimulation, concomitantly with impaired induction of the Th1-specific transcription factor T-bet. Accordingly, Ras-deficient mice failed to mount a protective Th1 response in vivo against the intracellular parasite Leishmania major, although they could be rendered resistant to infection if a Th1-biased milieu was provided during parasite challenge. Collectively, our data indicate that the TCR recruits distinct Ras isoforms for signal transduction in developing and mature T cells, thus providing a mechanism for differential signaling from the same surface receptor. Furthermore, we demonstrate for the first time that H-ras and N-ras act as critical controllers of Th1 responses, mostly by transmitting TCR signals for Th1 priming of CD4⁺ T cells.
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Ladygina N, Martin BR, Altman A. Dynamic palmitoylation and the role of DHHC proteins in T cell activation and anergy. Adv Immunol 2011; 109:1-44. [PMID: 21569911 DOI: 10.1016/b978-0-12-387664-5.00001-7] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Although protein S-palmitoylation was first characterized >30 years ago, and is implicated in the function, trafficking, and localization of many proteins, little is known about the regulation and physiological implications of this posttranslational modification. Palmitoylation of various signaling proteins required for TCR-induced T cell activation is also necessary for their proper function. Linker for activation of T cells (LAT) is an essential scaffolding protein involved in T cell development and activation, and we found that its palmitoylation is selectively impaired in anergic T cells. The recent discovery of the DHHC family of palmitoyl acyl transferases and the establishment of sensitive and quantitative proteomics-based methods for global analysis of the palmitoyl proteome led to significant progress in studying the biology and underlying mechanisms of cellular protein palmitoylation. We are using these approaches to explore the palmitoyl proteome in T lymphocytes and, specifically, the mechanistic basis for the impaired palmitoylation of LAT in anergic T cells. This chapter reviews the history of protein palmitoylation and its role in T cell activation, the DHHC family and new methodologies for global analysis of the palmitoyl proteome, and summarizes our recent work in this area. The new methodologies will accelerate the pace of research and provide a greatly improved mechanistic and molecular understanding of the complex process of protein palmitoylation and its regulation, and the substrate specificity of the novel DHHC family. Reversible protein palmitoylation will likely prove to be an important posttranslational mechanism that regulates cellular responses, similar to protein phosphorylation and ubiquitination.
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Affiliation(s)
- Nadejda Ladygina
- Division of Cell Biology, La Jolla Institute for Allergy and Immunology, California, USA
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GIMAP Proteins in T-Lymphocytes. JOURNAL OF SIGNAL TRANSDUCTION 2010; 2010:268589. [PMID: 21637352 PMCID: PMC3100574 DOI: 10.1155/2010/268589] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/28/2010] [Accepted: 06/16/2010] [Indexed: 12/21/2022]
Abstract
(GIMAPs) GTPase of the immunity associated protein family are a novel protein family of putative small GTPases. GIMAPs are mainly expressed in the cells of the immune system and have been associated with immunological functions, such as thymocyte development, apoptosis of peripheral lymphocytes and T helper cell differentiation. GIMAPs have also been linked to immunological diseases, such as T cell lymphopenia, leukemia and autoimmune diseases. In this review we examine the role of GIMAP proteins in T-lymphocyte biology.
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