1
|
Chang Y, Manivannan P, Doosti A, Lapinski PE, Chen D, Roose J, King PD. Cutting Edge: Induced Loss of Rasgrp1 in Peripheral CD4+ T Cells of Conditional Rasgrp1-Deficient Mice Reveals an Essential Role for Rasgrp1 in TCR/CD28-Induced Ras-MAPK Signaling. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2023; 211:917-922. [PMID: 37566514 PMCID: PMC10529702 DOI: 10.4049/jimmunol.2300138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Accepted: 07/25/2023] [Indexed: 08/13/2023]
Abstract
Ras guanine nucleotide-releasing protein 1 (Rasgrp1) is a Ras guanine nucleotide exchange factor that participates in the activation of the Ras-ERK signaling pathway in developing T cells and is required for efficient thymic T cell positive selection. However, the role of Rasgrp1 in mature peripheral T cells has not been definitively addressed, in part because peripheral T cells from constitutive Rasgrp1-deficient mice show an abnormal activated phenotype. In this study, we generated an inducible Rasgrp1-deficient mouse model to allow acute disruption of Rasgrp1 in peripheral CD4+ T cells in the context of normal T cell development. TCR/CD28-mediated activation of Ras-ERK signaling was blocked in Rasgrp1-deficient peripheral CD4+ T cells. Furthermore, Rasgrp1-deficient CD4+ T cells were unable to synthesize IL-2 and the high-affinity IL-2R and were unable to proliferate in response to TCR/CD28 stimulation. These findings highlight an essential function for Rasgrp1 for TCR/CD28-induced Ras-ERK activation in peripheral CD4+ T cells.
Collapse
Affiliation(s)
- Yating Chang
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Praveen Manivannan
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Abbas Doosti
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Philip E. Lapinski
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Di Chen
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Jeroen Roose
- Department of Anatomy, University of California, San Francisco, USA
| | - Philip D. King
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, USA
- Department of Anatomy, University of California, San Francisco, USA
| |
Collapse
|
2
|
Harley ITW, Allison K, Scofield RH. Polygenic autoimmune disease risk alleles impacting B cell tolerance act in concert across shared molecular networks in mouse and in humans. Front Immunol 2022; 13:953439. [PMID: 36090990 PMCID: PMC9450536 DOI: 10.3389/fimmu.2022.953439] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Accepted: 07/19/2022] [Indexed: 11/23/2022] Open
Abstract
Most B cells produced in the bone marrow have some level of autoreactivity. Despite efforts of central tolerance to eliminate these cells, many escape to periphery, where in healthy individuals, they are rendered functionally non-responsive to restimulation through their antigen receptor via a process termed anergy. Broad repertoire autoreactivity may reflect the chances of generating autoreactivity by stochastic use of germline immunoglobulin gene segments or active mechanisms may select autoreactive cells during egress to the naïve peripheral B cell pool. Likewise, it is unclear why in some individuals autoreactive B cell clones become activated and drive pathophysiologic changes in autoimmune diseases. Both of these remain central questions in the study of the immune system(s). In most individuals, autoimmune diseases arise from complex interplay of genetic risk factors and environmental influences. Advances in genome sequencing and increased statistical power from large autoimmune disease cohorts has led to identification of more than 200 autoimmune disease risk loci. It has been observed that autoantibodies are detectable in the serum years to decades prior to the diagnosis of autoimmune disease. Thus, current models hold that genetic defects in the pathways that control autoreactive B cell tolerance set genetic liability thresholds across multiple autoimmune diseases. Despite the fact these seminal concepts were developed in animal (especially murine) models of autoimmune disease, some perceive a disconnect between human risk alleles and those identified in murine models of autoimmune disease. Here, we synthesize the current state of the art in our understanding of human risk alleles in two prototypical autoimmune diseases – systemic lupus erythematosus (SLE) and type 1 diabetes (T1D) along with spontaneous murine disease models. We compare these risk networks to those reported in murine models of these diseases, focusing on pathways relevant to anergy and central tolerance. We highlight some differences between murine and human environmental and genetic factors that may impact autoimmune disease development and expression and may, in turn, explain some of this discrepancy. Finally, we show that there is substantial overlap between the molecular networks that define these disease states across species. Our synthesis and analysis of the current state of the field are consistent with the idea that the same molecular networks are perturbed in murine and human autoimmune disease. Based on these analyses, we anticipate that murine autoimmune disease models will continue to yield novel insights into how best to diagnose, prognose, prevent and treat human autoimmune diseases.
Collapse
Affiliation(s)
- Isaac T. W. Harley
- Division of Rheumatology, Department of Medicine, University of Colorado School of Medicine, Aurora, CO, United States
- Human Immunology and Immunotherapy Initiative (HI3), Department of Immunology, University of Colorado School of Medicine, Aurora, CO, United States
- Rheumatology Section, Medicine Service, Rocky Mountain Regional Veterans Affairs Medical Center, Aurora, CO, United States
- *Correspondence: Isaac T. W. Harley,
| | - Kristen Allison
- Division of Rheumatology, Department of Medicine, University of Colorado School of Medicine, Aurora, CO, United States
- Human Immunology and Immunotherapy Initiative (HI3), Department of Immunology, University of Colorado School of Medicine, Aurora, CO, United States
| | - R. Hal Scofield
- Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
- Arthritis & Clinical Immunology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, United States
- Medical/Research Service, US Department of Veterans Affairs Medical Center, Oklahoma City, OK, United States
| |
Collapse
|
3
|
Cooke M, Kazanietz MG. Overarching roles of diacylglycerol signaling in cancer development and antitumor immunity. Sci Signal 2022; 15:eabo0264. [PMID: 35412850 DOI: 10.1126/scisignal.abo0264] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Diacylglycerol (DAG) is a lipid second messenger that is generated in response to extracellular stimuli and channels intracellular signals that affect mammalian cell proliferation, survival, and motility. DAG exerts a myriad of biological functions through protein kinase C (PKC) and other effectors, such as protein kinase D (PKD) isozymes and small GTPase-regulating proteins (such as RasGRPs). Imbalances in the fine-tuned homeostasis between DAG generation by phospholipase C (PLC) enzymes and termination by DAG kinases (DGKs), as well as dysregulation in the activity or abundance of DAG effectors, have been widely associated with tumor initiation, progression, and metastasis. DAG is also a key orchestrator of T cell function and thus plays a major role in tumor immunosurveillance. In addition, DAG pathways shape the tumor ecosystem by arbitrating the complex, dynamic interaction between cancer cells and the immune landscape, hence representing powerful modifiers of immune checkpoint and adoptive T cell-directed immunotherapy. Exploiting the wide spectrum of DAG signals from an integrated perspective could underscore meaningful advances in targeted cancer therapy.
Collapse
Affiliation(s)
- Mariana Cooke
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.,Department of Medicine, Einstein Medical Center Philadelphia, Philadelphia, PA 19141, USA
| | - Marcelo G Kazanietz
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| |
Collapse
|
4
|
Fernández-Medarde A, Santos E. Ras GEF Mouse Models for the Analysis of Ras Biology and Signaling. METHODS IN MOLECULAR BIOLOGY (CLIFTON, N.J.) 2021; 2262:361-395. [PMID: 33977490 DOI: 10.1007/978-1-0716-1190-6_23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Animal models have become in recent years a crucial tool to understand the physiological and pathological roles of many cellular proteins. They allow analysis of the functional consequences of [1] complete or partial (time- or organ-limited) removal of specific proteins (knockout animals), [2] the exchange of a wild-type allele for a mutant or truncated version found in human illnesses (knock-in), or [3] the effect of overexpression of a given protein in the whole body or in specific organs (transgenic mice). In this regard, the study of phenotypes in Ras GEF animal models has allowed researchers to find specific functions for otherwise very similar proteins, uncovering their role in physiological contexts such as memory formation, lymphopoiesis, photoreception, or body homeostasis. In addition, mouse models have been used to unveil the functional role of Ras GEFs under pathological conditions, including Noonan syndrome, skin tumorigenesis, inflammatory diseases, diabetes, or ischemia among others. In the following sections, we will describe the methodological approaches employed for Ras GEF animal model analyses, as well as the main discoveries made.
Collapse
Affiliation(s)
- Alberto Fernández-Medarde
- Centro de Investigación del Cáncer-Instituto de Biología Molecular y Celular del Cáncer (CSIC-Universidad de Salamanca) and CIBERONC, Salamanca, Spain.
| | - Eugenio Santos
- Centro de Investigación del Cáncer-Instituto de Biología Molecular y Celular del Cáncer (CSIC-Universidad de Salamanca) and CIBERONC, Salamanca, Spain
| |
Collapse
|
5
|
Rchiad Z, Haidar M, Ansari HR, Tajeri S, Mfarrej S, Ben Rached F, Kaushik A, Langsley G, Pain A. Novel tumour suppressor roles for GZMA and RASGRP1 in Theileria annulata-transformed macrophages and human B lymphoma cells. Cell Microbiol 2020; 22:e13255. [PMID: 32830401 PMCID: PMC7685166 DOI: 10.1111/cmi.13255] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 08/03/2020] [Accepted: 08/07/2020] [Indexed: 12/22/2022]
Abstract
Theileria annulata is a tick-transmitted apicomplexan parasite that infects and transforms bovine leukocytes into disseminating tumours that cause a disease called tropical theileriosis. Using comparative transcriptomics we identified genes transcriptionally perturbed during Theileria-induced leukocyte transformation. Dataset comparisons highlighted a small set of genes associated with Theileria-transformed leukocyte dissemination. The roles of Granzyme A (GZMA) and RAS guanyl-releasing protein 1 (RASGRP1) were verified by CRISPR/Cas9-mediated knockdown. Knocking down expression of GZMA and RASGRP1 in attenuated macrophages led to a regain in their dissemination in Rag2/γC mice confirming their role as dissemination suppressors in vivo. We further evaluated the roles of GZMA and RASGRP1 in human B lymphomas by comparing the transcriptome of 934 human cancer cell lines to that of Theileria-transformed bovine host cells. We confirmed dampened dissemination potential of human B lymphomas that overexpress GZMA and RASGRP1. Our results provide evidence that GZMA and RASGRP1 have a novel tumour suppressor function in both T. annulata-infected bovine host leukocytes and in human B lymphomas.
Collapse
Affiliation(s)
- Zineb Rchiad
- Pathogen Genomics Laboratory, BESE Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia.,Laboratoire de Biologie Comparative des Apicomplexes, Faculté de Médecine, Université Paris Descartes - Sorbonne Paris Cité, Paris, France.,INSERM U1016, CNRS UMR8104, Cochin Institute, Paris, France.,Centre de Coalition, Innovation, et de prévention des Epidémies au Maroc (CIPEM), Mohammed VI Polytechnic University (UM6P), Ben Guerir, Morocco
| | - Malak Haidar
- Pathogen Genomics Laboratory, BESE Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia.,Laboratoire de Biologie Comparative des Apicomplexes, Faculté de Médecine, Université Paris Descartes - Sorbonne Paris Cité, Paris, France.,INSERM U1016, CNRS UMR8104, Cochin Institute, Paris, France
| | - Hifzur Rahman Ansari
- Pathogen Genomics Laboratory, BESE Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia.,King Abdullah International Medical Research Center (KAIMRC), King Abdulaziz Medical City, Ministry of National Guard Health Affairs, Jeddah, Saudi Arabia
| | - Shahin Tajeri
- Laboratoire de Biologie Comparative des Apicomplexes, Faculté de Médecine, Université Paris Descartes - Sorbonne Paris Cité, Paris, France.,INSERM U1016, CNRS UMR8104, Cochin Institute, Paris, France
| | - Sara Mfarrej
- Pathogen Genomics Laboratory, BESE Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Fathia Ben Rached
- Pathogen Genomics Laboratory, BESE Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Abhinav Kaushik
- Pathogen Genomics Laboratory, BESE Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Gordon Langsley
- Laboratoire de Biologie Comparative des Apicomplexes, Faculté de Médecine, Université Paris Descartes - Sorbonne Paris Cité, Paris, France.,INSERM U1016, CNRS UMR8104, Cochin Institute, Paris, France
| | - Arnab Pain
- Pathogen Genomics Laboratory, BESE Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia.,Global Station for Zoonosis Control, Global Institution for Collaborative Research and Education (GI-CoRE), Hokkaido University, Sapporo, Japan
| |
Collapse
|
6
|
RASGRP1 mutation in autoimmune lymphoproliferative syndrome-like disease. J Allergy Clin Immunol 2018; 142:595-604.e16. [DOI: 10.1016/j.jaci.2017.10.026] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Revised: 09/27/2017] [Accepted: 10/02/2017] [Indexed: 12/18/2022]
|
7
|
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.
Collapse
|
8
|
Huang YH, Tsai K, Tan SY, Kang S, Ford ML, Harder KW, Priatel JJ. 2B4-SAP signaling is required for the priming of naive CD8 + T cells by antigen-expressing B cells and B lymphoma cells. Oncoimmunology 2016; 6:e1267094. [PMID: 28344876 DOI: 10.1080/2162402x.2016.1267094] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Revised: 11/22/2016] [Accepted: 11/24/2016] [Indexed: 10/20/2022] Open
Abstract
Mutations in SH2D1A gene that encodes SAP (SLAM-associated protein) result in X-linked lymphoproliferative disease (XLP), a rare primary immunodeficiency disease defined by exquisite sensitivity to the B-lymphotropic Epstein-Barr virus (EBV) and B cell lymphomas. However, the precise mechanism of how the loss of SAP function contributes to extreme vulnerability to EBV and the development of B cell lymphomas remains unclear. Here, we investigate the hypothesis that SAP is critical for CD8+ T cell immune surveillance of antigen (Ag)-expressing B cells or B lymphoma cells under conditions of defined T cell receptor (TCR) signaling. Sh2d1a-/- CD8+ T cells exhibited greatly diminished proliferation relative to wild type when Ag-presenting-B cells or -B lymphoma cells served as the primary Ag-presenting cell (APC). By contrast, Sh2d1a-/- CD8+ T cells responded equivalently to wild-type CD8+ T cells when B cell-depleted splenocytes, melanoma cells or breast carcinoma cells performed Ag presentation. Through application of signaling lymphocyte activation molecule (SLAM) family receptor blocking antibodies or SLAM family receptor-deficient CD8+ T cells and APCs, we found that CD48 engagement on the B cell surface by 2B4 is crucial for initiating SAP-dependent signaling required for the Ag-driven CD8+ T cell proliferation and differentiation. Altogether, a pivotal role for SAP in promoting the expansion and differentiation of B cell-primed viral-specific naive CD8+ T cells may explain the selective immune deficiency of XLP patients to EBV and B cell lymphomas.
Collapse
Affiliation(s)
- Yu-Hsuan Huang
- British Columbia Children's Hospital Research Institute, Vancouver, British Columbia, Canada; Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Kevin Tsai
- British Columbia Children's Hospital Research Institute, Vancouver, British Columbia, Canada; Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Sara Y Tan
- British Columbia Children's Hospital Research Institute, Vancouver, British Columbia, Canada; Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Sohyeong Kang
- British Columbia Children's Hospital Research Institute, Vancouver, British Columbia, Canada; Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Mandy L Ford
- Department of Surgery, Emory University , Atlanta, GA, USA
| | - Kenneth W Harder
- Department of Microbiology and Immunology, University of British Columbia , Vancouver, British Columbia, Canada
| | - John J Priatel
- British Columbia Children's Hospital Research Institute, Vancouver, British Columbia, Canada; Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| |
Collapse
|
9
|
Zhou XJ, Nath SK, Qi YY, Sun C, Hou P, Zhang YM, Lv JC, Shi SF, Liu LJ, Chen R, Yang W, He KZ, Li Y, Zhang H. Novel identified associations of RGS1 and RASGRP1 variants in IgA Nephropathy. Sci Rep 2016; 6:35781. [PMID: 27804980 PMCID: PMC5090199 DOI: 10.1038/srep35781] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Accepted: 10/05/2016] [Indexed: 12/21/2022] Open
Abstract
Known susceptibility loci together can only explain about 6-8% of the disease heritability of IgA nephropathy (IgAN), suggesting that there are still a large number of genetic variants remained to be discovered. We previously identified IgAN and systemic lupus erythematosus (SLE)/lupus nephritis (LN) shared many loci based on GWAS on Chinese populations. The more recent study with high-density genotyping of immune-related loci in individuals with Asian ancestry identified 10 new and 6 suggestive loci in SLE. In the current study, we thus included all the lead SNPs from these 16 loci reported, and firstly tested their associations in 1,248 patients with sporadic IgAN, 737 patients with LN and 1,187 controls. Significant associations identified in IgAN were replicated in additional 500 patients and 2372 controls. rs12022418 in RGS1 (p = 3.0 × 10-6) and rs7170151 in RASGRP1 (p = 1.9 × 10-5) showed novel associations in IgAN. Compared to SNPs that were in LD with them, the associated variants showed higher potential of regulatory features by affecting gene expression. And systemic evaluation of GWAS data supported the pleiotropic effects of RGS1 and RASGRP1 variants in mediating human complex diseases. In conclusion, novel risk loci shared between IgAN and SLE/LN were identified, which may shed new light to exploit the potential pathogenesis for those two diseases.
Collapse
Affiliation(s)
- Xu-Jie Zhou
- Renal Division, Peking University First Hospital; Peking University Institute of Nephrology; Key Laboratory of Renal Disease, Ministry of Health of China; and Key Laboratory of Chronic Kidney Disease Prevention and Treatment (Peking University), Ministry of Education; Beijing, 100034, People's Republic of China
| | - Swapan K Nath
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, USA
| | - Yuan-Yuan Qi
- Renal Division, Peking University First Hospital; Peking University Institute of Nephrology; Key Laboratory of Renal Disease, Ministry of Health of China; and Key Laboratory of Chronic Kidney Disease Prevention and Treatment (Peking University), Ministry of Education; Beijing, 100034, People's Republic of China
| | - Celi Sun
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, USA
| | - Ping Hou
- Renal Division, Peking University First Hospital; Peking University Institute of Nephrology; Key Laboratory of Renal Disease, Ministry of Health of China; and Key Laboratory of Chronic Kidney Disease Prevention and Treatment (Peking University), Ministry of Education; Beijing, 100034, People's Republic of China
| | - Yue-Miao Zhang
- Renal Division, Peking University First Hospital; Peking University Institute of Nephrology; Key Laboratory of Renal Disease, Ministry of Health of China; and Key Laboratory of Chronic Kidney Disease Prevention and Treatment (Peking University), Ministry of Education; Beijing, 100034, People's Republic of China
| | - Ji-Cheng Lv
- Renal Division, Peking University First Hospital; Peking University Institute of Nephrology; Key Laboratory of Renal Disease, Ministry of Health of China; and Key Laboratory of Chronic Kidney Disease Prevention and Treatment (Peking University), Ministry of Education; Beijing, 100034, People's Republic of China
| | - Su-Fang Shi
- Renal Division, Peking University First Hospital; Peking University Institute of Nephrology; Key Laboratory of Renal Disease, Ministry of Health of China; and Key Laboratory of Chronic Kidney Disease Prevention and Treatment (Peking University), Ministry of Education; Beijing, 100034, People's Republic of China
| | - Li-Jun Liu
- Renal Division, Peking University First Hospital; Peking University Institute of Nephrology; Key Laboratory of Renal Disease, Ministry of Health of China; and Key Laboratory of Chronic Kidney Disease Prevention and Treatment (Peking University), Ministry of Education; Beijing, 100034, People's Republic of China
| | - Ruoyan Chen
- Department of Paediatrics and Adolescent Medicine Centre for Genomic Sciences, Queen Mary Hospital, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong
| | - Wanling Yang
- Department of Paediatrics and Adolescent Medicine Centre for Genomic Sciences, Queen Mary Hospital, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong
| | - Kevin Zhi He
- Department of Biostatistics, School of Public Health, University of Michigan, Ann Arbor, USA
| | - Yanming Li
- Department of Biostatistics, School of Public Health, University of Michigan, Ann Arbor, USA
| | - Hong Zhang
- Renal Division, Peking University First Hospital; Peking University Institute of Nephrology; Key Laboratory of Renal Disease, Ministry of Health of China; and Key Laboratory of Chronic Kidney Disease Prevention and Treatment (Peking University), Ministry of Education; Beijing, 100034, People's Republic of China
| |
Collapse
|
10
|
Salzer E, Cagdas D, Hons M, Mace EM, Garncarz W, Petronczki ÖY, Platzer R, Pfajfer L, Bilic I, Ban SA, Willmann KL, Mukherjee M, Supper V, Hsu HT, Banerjee PP, Sinha P, McClanahan F, Zlabinger GJ, Pickl WF, Gribben JG, Stockinger H, Bennett KL, Huppa JB, Dupré L, Sanal Ö, Jäger U, Sixt M, Tezcan I, Orange JS, Boztug K. RASGRP1 deficiency causes immunodeficiency with impaired cytoskeletal dynamics. Nat Immunol 2016; 17:1352-1360. [PMID: 27776107 DOI: 10.1038/ni.3575] [Citation(s) in RCA: 93] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Accepted: 09/01/2016] [Indexed: 12/15/2022]
Abstract
RASGRP1 is an important guanine nucleotide exchange factor and activator of the RAS-MAPK pathway following T cell antigen receptor (TCR) signaling. The consequences of RASGRP1 mutations in humans are unknown. In a patient with recurrent bacterial and viral infections, born to healthy consanguineous parents, we used homozygosity mapping and exome sequencing to identify a biallelic stop-gain variant in RASGRP1. This variant segregated perfectly with the disease and has not been reported in genetic databases. RASGRP1 deficiency was associated in T cells and B cells with decreased phosphorylation of the extracellular-signal-regulated serine kinase ERK, which was restored following expression of wild-type RASGRP1. RASGRP1 deficiency also resulted in defective proliferation, activation and motility of T cells and B cells. RASGRP1-deficient natural killer (NK) cells exhibited impaired cytotoxicity with defective granule convergence and actin accumulation. Interaction proteomics identified the dynein light chain DYNLL1 as interacting with RASGRP1, which links RASGRP1 to cytoskeletal dynamics. RASGRP1-deficient cells showed decreased activation of the GTPase RhoA. Treatment with lenalidomide increased RhoA activity and reversed the migration and activation defects of RASGRP1-deficient lymphocytes.
Collapse
Affiliation(s)
- Elisabeth Salzer
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria.,Ludwig Boltzmann Institute for Rare and Undiagnosed Diseases, Vienna, Austria
| | - Deniz Cagdas
- Section of Pediatric Immunology, Hacettepe University, Ihsan Dogramaci Children's Hospital, Ankara, Turkey
| | - Miroslav Hons
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Emily M Mace
- Center for Human Immunobiology, Baylor College of Medicine and Texas Children's Hospital, Houston, Texas, USA
| | - Wojciech Garncarz
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria.,Ludwig Boltzmann Institute for Rare and Undiagnosed Diseases, Vienna, Austria
| | - Özlem Yüce Petronczki
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria.,Ludwig Boltzmann Institute for Rare and Undiagnosed Diseases, Vienna, Austria
| | - René Platzer
- Institute for Hygiene and Applied Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | - Laurène Pfajfer
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria.,Ludwig Boltzmann Institute for Rare and Undiagnosed Diseases, Vienna, Austria
| | - Ivan Bilic
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Sol A Ban
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Katharina L Willmann
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Malini Mukherjee
- Center for Human Immunobiology, Baylor College of Medicine and Texas Children's Hospital, Houston, Texas, USA
| | - Verena Supper
- Institute for Hygiene and Applied Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | - Hsiang Ting Hsu
- Center for Human Immunobiology, Baylor College of Medicine and Texas Children's Hospital, Houston, Texas, USA
| | - Pinaki P Banerjee
- Center for Human Immunobiology, Baylor College of Medicine and Texas Children's Hospital, Houston, Texas, USA
| | - Papiya Sinha
- Center for Human Immunobiology, Baylor College of Medicine and Texas Children's Hospital, Houston, Texas, USA
| | - Fabienne McClanahan
- Centre for Haemato-Oncology, Barts Cancer Institute - a CR-UK Centre of Excellence, Queen Mary University of London, London, UK
| | - Gerhard J Zlabinger
- Institute of Immunology, Center of Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | - Winfried F Pickl
- Christian Doppler Laboratory for Immunomodulation and Institute of Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | - John G Gribben
- Centre for Haemato-Oncology, Barts Cancer Institute - a CR-UK Centre of Excellence, Queen Mary University of London, London, UK
| | - Hannes Stockinger
- Institute for Hygiene and Applied Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | - Keiryn L Bennett
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Johannes B Huppa
- Institute for Hygiene and Applied Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | - Loïc Dupré
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria.,Ludwig Boltzmann Institute for Rare and Undiagnosed Diseases, Vienna, Austria.,Centre de Physiopathologie de Toulouse Purpan (CPTP), INSERM, UMR1043, Toulouse Purpan University Hospital, Toulouse, France
| | - Özden Sanal
- Section of Pediatric Immunology, Hacettepe University, Ihsan Dogramaci Children's Hospital, Ankara, Turkey
| | - Ulrich Jäger
- Department of Medicine I, Division of Hematology and Hemostaseology, Medical University of Vienna, Vienna, Austria
| | - Michael Sixt
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Ilhan Tezcan
- Section of Pediatric Immunology, Hacettepe University, Ihsan Dogramaci Children's Hospital, Ankara, Turkey
| | - Jordan S Orange
- Center for Human Immunobiology, Baylor College of Medicine and Texas Children's Hospital, Houston, Texas, USA
| | - Kaan Boztug
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria.,Ludwig Boltzmann Institute for Rare and Undiagnosed Diseases, Vienna, Austria.,Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria.,St. Anna Kinderspital and Children's Cancer Research Institute, Department of Pediatrics, Medical University of Vienna, Vienna, Austria
| |
Collapse
|
11
|
Smith C, Buhlmann JE, Wang X, Bartlett A, Lim B, Barrington RA. CD275-Independent IL-17-Producing T Follicular Helper-like Cells in Lymphopenic Autoimmune-Prone Mice. THE JOURNAL OF IMMUNOLOGY 2016; 196:4935-46. [PMID: 27183569 DOI: 10.4049/jimmunol.1402193] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2014] [Accepted: 04/15/2016] [Indexed: 12/27/2022]
Abstract
T cells undergo homeostatic expansion and acquire an activated phenotype in lymphopenic microenvironments. Restoration of normal lymphocyte numbers typically re-establishes normal homeostasis, and proinflammatory cytokine production returns to baseline. Mice deficient in guanine nucleotide exchange factor RasGRP1 exhibit dysregulated homeostatic expansion, which manifests as lymphoproliferative disease with autoantibody production. Our previous work revealed that autoreactive B cells lacking RasGRP1 break tolerance early during development, as well as during germinal center responses, suggesting that T cell-independent and T cell-dependent mechanisms are responsible. Examination of whether a particular T cell subset is involved in the breach of B cell tolerance revealed increased Th17 cells in Rasgrp1-deficient mice relative to control mice. Rasgrp1-deficient mice lacking IL-17R had fewer germinal centers, and germinal centers that formed contained fewer autoreactive B cells, suggesting that IL-17 signaling is required for a break in B cell tolerance in germinal centers. Interestingly, a fraction of Th17 cells from Rasgrp1-deficient mice were CXCR5(+) and upregulated levels of CD278 coordinate with their appearance in germinal centers, all attributes of T follicular helper cells (Tfh17). To determine whether CD278-CD275 interactions were required for the development of Tfh17 cells and for autoantibody, Rasgrp1-deficient mice were crossed with CD275-deficient mice. Surprisingly, mice deficient in RasGRP1 and CD275 formed Tfh17 cells and germinal centers and produced similar titers of autoantibodies as mice deficient in only RasGRP1. Therefore, these studies suggest that requirements for Tfh cell development change in lymphopenia-associated autoimmune settings.
Collapse
Affiliation(s)
- Christopher Smith
- Department of Microbiology and Immunology, University of South Alabama, Mobile, AL 36688; and
| | - Janet E Buhlmann
- Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02115
| | - Xiaogan Wang
- Department of Microbiology and Immunology, University of South Alabama, Mobile, AL 36688; and
| | - Amber Bartlett
- Department of Microbiology and Immunology, University of South Alabama, Mobile, AL 36688; and
| | - Bing Lim
- Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02115
| | - Robert A Barrington
- Department of Microbiology and Immunology, University of South Alabama, Mobile, AL 36688; and
| |
Collapse
|
12
|
Guo B, Rothstein TL. RasGRP1 Is an Essential Signaling Molecule for Development of B1a Cells with Autoantigen Receptors. THE JOURNAL OF IMMUNOLOGY 2016; 196:2583-90. [PMID: 26851222 DOI: 10.4049/jimmunol.1502132] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Accepted: 01/04/2016] [Indexed: 01/08/2023]
Abstract
B1a cells, particularly the PD-L2(+) B1a cell subset, are enriched with autoantigen-specific receptors. However, the underlying molecular mechanism responsible for the skewed selection of autoreactive B1a cells remains unclear. In this study, we find that B1 cells express only Ras guanyl nucleotide-releasing protein (RasGRP) 1, whereas B2 cells express mostly RasGRP3 and little RasGRP1. RasGRP1 is indispensable for transduction of weak signals. RasGRP1 deficiency markedly impairs B1a cell development and reduces serum natural IgM production; in particular, B1a cells that express autoantigen receptors, such as anti-phosphatidylcholine B1a cells, are virtually eliminated. Thus, unlike Btk and other signalosome components, RasGRP1 deficiency selectively affects only the B1a cell population with autoantigen receptors rather than the entire pool of B1a cells.
Collapse
Affiliation(s)
- Benchang Guo
- Center for Oncology and Cell Biology, Feinstein Institute for Medical Research, Manhasset, NY 11030;
| | - Thomas L Rothstein
- Center for Oncology and Cell Biology, Feinstein Institute for Medical Research, Manhasset, NY 11030; Department of Medicine, Hofstra North Shore-Long Island Jewish School of Medicine, Manhasset, NY 11030; and Department of Molecular Medicine, Hofstra North Shore-Long Island Jewish School of Medicine, Manhasset, NY 11030
| |
Collapse
|
13
|
Li JY, Tao F, Wu XX, Tan YZ, He L, Lu H. Common RASGRP1 Gene Variants That Confer Risk of Type 2 Diabetes. Genet Test Mol Biomarkers 2015; 19:439-43. [PMID: 26076219 DOI: 10.1089/gtmb.2015.0005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Genome-wide association studies have validated the RAS guanyl nucleotide-releasing protein 1 (RASGRP1) gene as a type 2 diabetes (T2D) susceptibility locus. AIMS This study aimed to replicate and verify the association of RASGRP1 tag single-nucleotide polymorphisms with T2D in a Chinese Han population. METHODS Eleven common variants of RASGRP1 were detected using TaqMan technology in 1272 healthy controls and 1234 T2D patients. All study participants were unrelated members of the Han ethnic group in China. In this study, the rs7403531 genotype frequency differed significantly between T2D patients and controls (allele: adjusted p=8.30×10(-6), genotype: adjusted p=2.50×10(-5), OR=1.366 [95% CI=1.206-1.546]). The rs4465567-rs4567661 C-A and C-C haplotypes were also significant risk factors for T2D (adjusted p=0.0002 and p=0.0006, respectively) with a global p-value of 6.46×10(-5). These results indicate that in a Chinese Han population, RASGRP1 variants, particularly rs7403531, confer a risk for developing T2D.
Collapse
Affiliation(s)
- Jun-Yan Li
- 1 Diabetes Research Institute, Department of Endocrinology, Shanghai Key Laboratory of Traditional Chinese Clinical Medicine, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine , Shanghai, China
| | - Feng Tao
- 1 Diabetes Research Institute, Department of Endocrinology, Shanghai Key Laboratory of Traditional Chinese Clinical Medicine, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine , Shanghai, China
| | - Xin-Xing Wu
- 2 Shanghai Technical Institute of Electronics & Information , Shanghai, China
| | - Ying-Zi Tan
- 1 Diabetes Research Institute, Department of Endocrinology, Shanghai Key Laboratory of Traditional Chinese Clinical Medicine, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine , Shanghai, China
| | - Lin He
- 3 Bio-X Institutes, Shanghai Jiao Tong University , Shanghai, China
| | - Hao Lu
- 1 Diabetes Research Institute, Department of Endocrinology, Shanghai Key Laboratory of Traditional Chinese Clinical Medicine, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine , Shanghai, China
| |
Collapse
|
14
|
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
Collapse
Affiliation(s)
- Stephen R Daley
- Department of Immunology, John Curtin School of Medical Research, The Australian National University, Canberra, Australia
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
15
|
Bartlett A, Buhlmann JE, Stone J, Lim B, Barrington RA. Multiple checkpoint breach of B cell tolerance in Rasgrp1-deficient mice. THE JOURNAL OF IMMUNOLOGY 2013; 191:3605-13. [PMID: 23997211 DOI: 10.4049/jimmunol.1202892] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Lymphopenic hosts offer propitious microenvironments for expansion of autoreactive B and T cells. Despite this, many lymphopenic hosts do not develop autoimmune disease, suggesting that additional factors are required for breaching self-tolerance in the setting of lymphopenia. Mice deficient in guanine nucleotide exchange factor Rasgrp1 develop a lymphoproliferative disorder with features of human systemic lupus erythematosus. Early in life, Rasgrp1-deficient mice have normal B cell numbers but are T lymphopenic, leading to defective homeostatic expansion of CD4 T cells. To investigate whether B cell-intrinsic mechanisms also contribute to autoimmunity, Rasgrp1-deficient mice were bred to mice containing a knockin autoreactive BCR transgene (564Igi), thereby allowing the fate of autoreactive B cells to be assessed. During B cell development, the frequency of receptor-edited 564Igi B cells was reduced in Rasrp1-deficient mice compared with Rasgrp1-sufficient littermate control mice, suggesting that tolerance was impaired. In addition, the number of 564Igi transitional B cells was increased in Rasgrp1-deficient mice compared with control mice. Immature 564Igi B cells in bone marrow and spleen lacking RasGRP1 expressed lower levels of Bim mRNA and protein, suggesting that autoreactive B cells elude clonal deletion during development. Concomitant with increased serum autoantibodies, Rasgrp1-deficient mice developed spontaneous germinal centers at 8-10 wk of age. The frequency and number of 564Igi B cells within these germinal centers were significantly increased in Rasgrp1-deficient mice relative to control mice. Taken together, these studies suggest that autoreactive B cells lacking Rasgrp1 break central and peripheral tolerance through both T cell-independent and -dependent mechanisms.
Collapse
Affiliation(s)
- Amber Bartlett
- Department of Microbiology and Immunology, University of South Alabama, Mobile, AL 36688
| | | | | | | | | |
Collapse
|
16
|
Rangachari M, Zhu C, Sakuishi K, Xiao S, Karman J, Chen A, Angin M, Wakeham A, Greenfield EA, Sobel RA, Okada H, McKinnon PJ, Mak TW, Addo MM, Anderson AC, Kuchroo VK. Bat3 promotes T cell responses and autoimmunity by repressing Tim-3–mediated cell death and exhaustion. Nat Med 2012; 18:1394-400. [PMID: 22863785 DOI: 10.1038/nm.2871] [Citation(s) in RCA: 270] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2011] [Accepted: 06/14/2012] [Indexed: 12/14/2022]
Abstract
T cell immunoglobulin and mucin domain–containing 3 (Tim-3) is an inhibitory receptor that is expressed on exhausted T cells during infection with HIV-1 and hepatitis C virus. By contrast, Tim-3 expression and function are defective in multiple human autoimmune diseases. However, the molecular mechanisms modulating Tim-3 function are not well understood. Here we show that human leukocyte antigen B (HLA-B)-associated transcript 3 (Bat3) binds to, and represses the function of, Tim-3. Bat3 protects T helper type 1 (TH1) cells from galectin-9–mediated cell death and promotes both proliferation and proinflammatory cytokine production. Bat3-deficient T cells have elevated expression of exhaustion-associated molecules such as Tim-3, Lag3, Prdm1 and Pbx3, and Bat3 knockdown in myelin-antigen–specific CD4+ T cells markedly inhibits the development of experimental autoimmune encephalomyelitis while promoting the expansion of a dysfunctional Tim-3hi, interferon-γ (IFN-γ)loCD4+ cell population. Furthermore, expression of Bat3 is reduced in exhausted Tim-3+ T cells from mouse tumors and HIV-1–infected individuals. These data indicate that Bat3 acts as an inhibitor of Tim-3–dependent exhaustion and cell death. Bat3 may thus represent a viable therapeutic target in autoimmune disorders, chronic infections and cancers.
Collapse
Affiliation(s)
- Manu Rangachari
- Center for Neurologic Diseases, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
17
|
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.
Collapse
Affiliation(s)
- Kris A Reedquist
- Division of Clinical Immunology and Rheumatology, Department of Experimental Immunology, Academic Medical Center, University of Amsterdam, The Netherlands
| | | |
Collapse
|
18
|
Regulation of RasGRP1 function in T cell development and activation by its unique tail domain. PLoS One 2012; 7:e38796. [PMID: 22719950 PMCID: PMC3373593 DOI: 10.1371/journal.pone.0038796] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2012] [Accepted: 05/07/2012] [Indexed: 12/30/2022] Open
Abstract
The Ras-guanyl nucleotide exchange factor RasGRP1 plays a critical role in T cell receptor-mediated Erk activation. Previous studies have emphasized the importance of RasGRP1 in the positive selection of thymocytes, activation of T cells, and control of autoimmunity. RasGRP1 consists of a number of well-characterized domains, which it shares with its other family members; however, RasGRP1 also contains an ∼200 residue-long tail domain, the function of which is unknown. To elucidate the physiological role of this domain, we generated knock-in mice expressing RasGRP1 without the tail domain. Further analysis of these knock-in mice showed that thymocytes lacking the tail domain of RasGRP1 underwent aberrant thymic selection and, following TCR stimulation, were unable to activate Erk. Furthermore, the deletion of the tail domain led to enhanced CD4+ T cell expansion in aged mice, as well as the production of autoantibodies. Mechanistically, the tail-deleted form of RasGRP1 was not able to traffic to the cell membrane following stimulation, indicating a potential reason for its inability to activate Erk. While the DAG-binding C1 domain of RasGRP1 has long been recognized as an important factor mediating Erk activation, we have revealed the physiological relevance of the tail domain in RasGRP1 function and control of Erk signaling.
Collapse
|
19
|
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.
Collapse
|
20
|
Abstract
Thymocytes must transit at least two distinct developmental checkpoints, governed by signals that emanate from either the pre-T cell receptor (pre-TCR) or the TCR to the small G protein Ras before emerging as functional T lymphocytes. Recent studies have shown a role for the Ras guanine exchange factor (RasGEF) Sos1 at the pre-TCR checkpoint. At the second checkpoint, the quality of signaling through the TCR is interrogated to ensure the production of an appropriate T cell repertoire. Although RasGRP1 is the only confirmed RasGEF required at the TCR checkpoint, current models suggest that the intensity and character of Ras activation, facilitated by both Sos and RasGRP1, will govern the boundary between survival (positive selection) and death (negative selection) at this stage. Using mouse models, we have assessed the independent and combined roles for the RasGEFs Sos1, Sos2, and RasGRP1 during thymocyte development. Although Sos1 was the dominant RasGEF at the pre-TCR checkpoint, combined Sos1/RasGRP1 deletion was required to effectively block development at this stage. Conversely, while RasGRP1 deletion efficiently blocked positive selection, combined RasGRP1/Sos1 deletion was required to block negative selection. This functional redundancy in RasGEFs during negative selection may act as a failsafe mechanism ensuring appropriate central tolerance.
Collapse
|
21
|
Shin J, O'Brien TF, Grayson JM, Zhong XP. Differential regulation of primary and memory CD8 T cell immune responses by diacylglycerol kinases. THE JOURNAL OF IMMUNOLOGY 2012; 188:2111-7. [PMID: 22271650 DOI: 10.4049/jimmunol.1102265] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The manipulation of signals downstream of the TCR can have profound consequences for T cell development, function, and homeostasis. Diacylglycerol (DAG) produced after TCR stimulation functions as a secondary messenger and mediates the signaling to Ras-MEK-Erk and NF-κB pathways in T cells. DAG kinases (DGKs) convert DAG into phosphatidic acid, resulting in termination of DAG signaling. In this study, we demonstrate that DAG metabolism by DGKs can serve a crucial function in viral clearance upon lymphocytic choriomeningitis virus infection. Ag-specific CD8(+) T cells from DGKα(-/-) and DGKζ(-/-) mice show enhanced expansion and increased cytokine production after lymphocytic choriomeningitis virus infection, yet DGK-deficient memory CD8(+) T cells exhibit impaired expansion after rechallenge. Thus, DGK activity plays opposing roles in the expansion of CD8(+) T cells during the primary and memory phases of the immune response, whereas consistently inhibiting antiviral cytokine production.
Collapse
Affiliation(s)
- Jinwook Shin
- Department of Pediatrics, Duke University Medical Center, Durham, NC 27710, USA
| | | | | | | |
Collapse
|
22
|
Abstract
Ras guanyl nucleotide releasing proteins (RasGRPs) are guanyl nucleotide exchange factors that activate Ras and related GTPases such as Rap. Like Sos proteins, RasGRPs have a catalytic region composed of a Ras exchange motif (REM) and a CDC25 domain. RasGRPs also possess a pair of atypical EF hands that may bind calcium in vivo and a C1 domain resembling the diacylglycerol (DAG)-binding domain of protein kinase C. DAG directly activates RasGRPs by a membrane recruitment mechanism as well as indirectly by PKC-mediated phosphorylation. RasGRPs are prominently expressed in blood cells. RasGRP1 acts downstream of TCR, while RasGRP1 and RasGRP3 both act downstream of BCR. Together, they regulate Ras in adaptive immune cells. RasGRP2, through Rap, plays a role in controlling platelet adhesion, while RasGRP4 controls Ras activation in mast cells. RasGRP malfunction likely contributes to autoimmunity and may contribute to blood malignancies. RasGRPs might prove to be viable drug targets. The intracellular site of RasGRP action and the relationship between RasGRPs and other Ras regulatory mechanisms are subjects of lively debate.
Collapse
Affiliation(s)
- James C Stone
- Department of Biochemistry, University of Alberta, Edmonton, AB, Canada
| |
Collapse
|
23
|
Omilusik K, Priatel J, Chen X, Wang Y, Xu H, Choi K, Gopaul R, McIntyre-Smith A, Teh HS, Tan R, Bech-Hansen N, Waterfield D, Fedida D, Hunt S, Jefferies W. The CaV1.4 Calcium Channel Is a Critical Regulator of T Cell Receptor Signaling and Naive T Cell Homeostasis. Immunity 2011; 35:349-60. [DOI: 10.1016/j.immuni.2011.07.011] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2009] [Revised: 06/09/2011] [Accepted: 07/22/2011] [Indexed: 12/12/2022]
|
24
|
Abstract
Second messenger molecules relay, amplify, and diversify cell surface receptor signals. Two important examples are phosphorylated D-myo-inositol derivatives, such as phosphoinositide lipids within cellular membranes, and soluble inositol phosphates. Here, we review how phosphoinositide metabolism generates multiple second messengers with important roles in T-cell development and function. They include soluble inositol(1,4,5)trisphosphate, long known for its Ca(2+)-mobilizing function, and phosphatidylinositol(3,4,5)trisphosphate, whose generation by phosphoinositide 3-kinase and turnover by the phosphatases PTEN and SHIP control a key "hub" of TCR signaling. More recent studies unveiled important second messenger functions for diacylglycerol, phosphatidic acid, and soluble inositol(1,3,4,5)tetrakisphosphate (IP(4)) in immune cells. Inositol(1,3,4,5)tetrakisphosphate acts as a soluble phosphatidylinositol(3,4,5)trisphosphate analog to control protein membrane recruitment. We propose that phosphoinositide lipids and soluble inositol phosphates (IPs) can act as complementary partners whose interplay could have broadly important roles in cellular signaling.
Collapse
Affiliation(s)
- Yina H Huang
- Department of Pathology, Washington University School of Medicine, St. Louis, Missouri 63110, USA
| | | |
Collapse
|
25
|
Priatel JJ, Chen X, Huang YH, Chow MT, Zenewicz LA, Coughlin JJ, Shen H, Stone JC, Tan R, Teh HS. RasGRP1 regulates antigen-induced developmental programming by naive CD8 T cells. THE JOURNAL OF IMMUNOLOGY 2009; 184:666-76. [PMID: 20007535 DOI: 10.4049/jimmunol.0803521] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Ag encounter by naive CD8 T cells initiates a developmental program consisting of cellular proliferation, changes in gene expression, and the formation of effector and memory T cells. The strength and duration of TCR signaling are known to be important parameters regulating the differentiation of naive CD8 T cells, although the molecular signals arbitrating these processes remain poorly defined. The Ras-guanyl nucleotide exchange factor RasGRP1 has been shown to transduce TCR-mediated signals critically required for the maturation of developing thymocytes. To elucidate the role of RasGRP1 in CD8 T cell differentiation, in vitro and in vivo experiments were performed with 2C TCR transgenic CD8 T cells lacking RasGRP1. In this study, we report that RasGRP1 regulates the threshold of T cell activation and Ag-induced expansion, at least in part, through the regulation of IL-2 production. Moreover, RasGRP1(-/-) 2C CD8 T cells exhibit an anergic phenotype in response to cognate Ag stimulation that is partially reversible upon the addition of exogenous IL-2. By contrast, the capacity of IL-2/IL-2R interactions to mediate Ras activation and CD8 T cell expansion and differentiation appears to be largely RasGRP1-independent. Collectively, our results demonstrate that RasGRP1 plays a selective role in T cell signaling, controlling the initiation and duration of CD8 T cell immune responses.
Collapse
Affiliation(s)
- John J Priatel
- Child and Family Research Institute, Vancouver, British Columbia, Canada.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
26
|
Chen X, Priatel JJ, Chow MT, Teh HS. Preferential development of CD4 and CD8 T regulatory cells in RasGRP1-deficient mice. THE JOURNAL OF IMMUNOLOGY 2008; 180:5973-82. [PMID: 18424717 DOI: 10.4049/jimmunol.180.9.5973] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
RasGRP1 and Sos are two Ras-guanyl-nucleotide exchange factors that link TCR signal transduction to Ras and MAPK activation. Recent studies demonstrate positive selection of developing thymocytes is crucially dependent on RasGRP1, whereas negative selection of autoreactive thymocytes appears to be RasGRP1 independent. However, the role of RasGRP1 in T regulatory (Treg) cell development and function is unknown. In this study, we characterized the development and function of CD4(+)CD25(+)Foxp3(+) and CD8(+)CD44(high)CD122(+) Treg lineages in RasGRP1(-/-) mice. Despite impaired CD4 Treg cell development in the thymus, the periphery of RasGRP1(-/-) mice contained significantly increased frequencies of CD4(+)Foxp3(+) Treg cells that possessed a more activated cell surface phenotype. Furthermore, on a per cell basis, CD4(+)Foxp3(+) Treg cells from mutant mice are more suppressive than their wild-type counterparts. Our data also suggest that the lymphopenic environment in the mutant mice plays a dominant role of favored peripheral development of CD4 Treg cells. These studies suggest that whereas RasGRP1 is crucial for the intrathymic development of CD4 Treg cells, it is not required for their peripheral expansion and function. By contrast to CD4(+)CD25(+)Foxp3(+) T cells, intrathymic development of CD8(+)CD44(high)CD122(+) Treg cells is unaffected by the RasGRP1(-/-) mutation. Moreover, RasGRP1(-/-) mice contained greater numbers of CD8(+)CD44(high)CD122(+) T cells in the spleen, relative to wild-type mice. Activated CD8 Treg cells from RasGRP1(-/-) mice retained their ability to synthesize IL-10 and suppress the proliferation of wild-type CD8(+)CD122(-) T cells, albeit at a much lower efficiency than wild-type CD8 Treg cells.
Collapse
Affiliation(s)
- Xiaoxi Chen
- Department of Microbiology and Immunology, Life Science Centre, University of British Columbia, 2350 Health Science Mall, Vancouver, BC, Canada
| | | | | | | |
Collapse
|