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Liu T, Xia S. The Proteostasis of Thymic Stromal Cells in Health and Diseases. Protein J 2024; 43:447-463. [PMID: 38622349 DOI: 10.1007/s10930-024-10197-x] [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] [Accepted: 04/05/2024] [Indexed: 04/17/2024]
Abstract
The thymus is the key immune organ for the development of T cells. Different populations of thymic stromal cells interact with T cells, thereby controlling the dynamic development of T cells through their differentiation and function. Proteostasis represents a balance between protein expression, folding, and modification and protein clearance, and its fluctuation usually depends at least partially on related protein regulatory systems for further survival and effects. However, in terms of the substantial requirement for self-antigens and their processing burden, increasing evidence highlights that protein regulation contributes to the physiological effects of thymic stromal cells. Impaired proteostasis may expedite the progression of thymic involution and dysfunction, accompanied by the development of autoimmune diseases or thymoma. Hence, in this review, we summarize the regulation of proteostasis within different types of thymic stromal cells under physiological and pathological conditions to identify potential targets for thymic regeneration and immunotherapy.
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Affiliation(s)
- Ting Liu
- Department of Immunology, School of Medicine, Jiangsu University, 301, Xuefu Road, Zhenjiang, Jiangsu, 212013, China
| | - Sheng Xia
- Department of Immunology, School of Medicine, Jiangsu University, 301, Xuefu Road, Zhenjiang, Jiangsu, 212013, China.
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2
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Hardtke-Wolenski M, Landwehr-Kenzel S. Tipping the balance in autoimmunity: are regulatory t cells the cause, the cure, or both? Mol Cell Pediatr 2024; 11:3. [PMID: 38507159 PMCID: PMC10954601 DOI: 10.1186/s40348-024-00176-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2023] [Accepted: 03/07/2024] [Indexed: 03/22/2024] Open
Abstract
Regulatory T cells (Tregs) are a specialized subgroup of T-cell lymphocytes that is crucial for maintaining immune homeostasis and preventing excessive immune responses. Depending on their differentiation route, Tregs can be subdivided into thymically derived Tregs (tTregs) and peripherally induced Tregs (pTregs), which originate from conventional T cells after extrathymic differentiation at peripheral sites. Although the regulatory attributes of tTregs and pTregs partially overlap, their modes of action, protein expression profiles, and functional stability exhibit specific characteristics unique to each subset. Over the last few years, our knowledge of Treg differentiation, maturation, plasticity, and correlations between their phenotypes and functions has increased. Genetic and functional studies in patients with numeric and functional Treg deficiencies have contributed to our mechanistic understanding of immune dysregulation and autoimmune pathologies. This review provides an overview of our current knowledge of Treg biology, discusses monogenetic Treg pathologies and explores the role of Tregs in various other autoimmune disorders. Additionally, we discuss novel approaches that explore Tregs as targets or agents of innovative treatment options.
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Affiliation(s)
- Matthias Hardtke-Wolenski
- Hannover Medical School, Department of Gastroenterology Hepatology, Infectious Diseases and Endocrinology, Carl-Neuberg-Str. 1, Hannover, 30625, Germany
- University Hospital Essen, Institute of Medical Microbiology, University Duisburg-Essen, Hufelandstraße 55, Essen, 45122, Germany
| | - Sybille Landwehr-Kenzel
- Hannover Medical School, Department of Pediatric Pneumology, Allergology and Neonatology, Carl-Neuberg-Str. 1, Hannover, 30625, Germany.
- Hannover Medical School, Institute of Transfusion Medicine and Transplant Engineering, Carl-Neuberg-Str. 1, Hannover, 30625, Germany.
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3
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Yu H, Yang W, Cao M, Lei Q, Yuan R, Xu H, Cui Y, Chen X, Su X, Zhuo H, Lin L. Mechanism study of ubiquitination in T cell development and autoimmune disease. Front Immunol 2024; 15:1359933. [PMID: 38562929 PMCID: PMC10982411 DOI: 10.3389/fimmu.2024.1359933] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Accepted: 02/19/2024] [Indexed: 04/04/2024] Open
Abstract
T cells play critical role in multiple immune processes including antigen response, tumor immunity, inflammation, self-tolerance maintenance and autoimmune diseases et. Fetal liver or bone marrow-derived thymus-seeding progenitors (TSPs) settle in thymus and undergo T cell-lineage commitment, proliferation, T cell receptor (TCR) rearrangement, and thymic selections driven by microenvironment composed of thymic epithelial cells (TEC), dendritic cells (DC), macrophage and B cells, thus generating T cells with diverse TCR repertoire immunocompetent but not self-reactive. Additionally, some self-reactive thymocytes give rise to Treg with the help of TEC and DC, serving for immune tolerance. The sequential proliferation, cell fate decision, and selection during T cell development and self-tolerance establishment are tightly regulated to ensure the proper immune response without autoimmune reaction. There are remarkable progresses in understanding of the regulatory mechanisms regarding ubiquitination in T cell development and the establishment of self-tolerance in the past few years, which holds great potential for further therapeutic interventions in immune-related diseases.
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Affiliation(s)
- Hui Yu
- Department of Urology, Medical Research Center, Department of Neurosurgery, The Third People’s Hospital of Chengdu, The Affiliated Hospital of Southwest Jiaotong University, The Second Chengdu Hospital Affiliated to Chongqing Medical University, Chengdu, China
| | - Wenyong Yang
- Department of Urology, Medical Research Center, Department of Neurosurgery, The Third People’s Hospital of Chengdu, The Affiliated Hospital of Southwest Jiaotong University, The Second Chengdu Hospital Affiliated to Chongqing Medical University, Chengdu, China
| | - Min Cao
- Department of Urology, Medical Research Center, Department of Neurosurgery, The Third People’s Hospital of Chengdu, The Affiliated Hospital of Southwest Jiaotong University, The Second Chengdu Hospital Affiliated to Chongqing Medical University, Chengdu, China
| | - Qingqiang Lei
- Department of Urology, Medical Research Center, Department of Neurosurgery, The Third People’s Hospital of Chengdu, The Affiliated Hospital of Southwest Jiaotong University, The Second Chengdu Hospital Affiliated to Chongqing Medical University, Chengdu, China
| | - Renbin Yuan
- Department of Urology, Medical Research Center, Department of Neurosurgery, The Third People’s Hospital of Chengdu, The Affiliated Hospital of Southwest Jiaotong University, The Second Chengdu Hospital Affiliated to Chongqing Medical University, Chengdu, China
| | - He Xu
- Department of Urology, Medical Research Center, Department of Neurosurgery, The Third People’s Hospital of Chengdu, The Affiliated Hospital of Southwest Jiaotong University, The Second Chengdu Hospital Affiliated to Chongqing Medical University, Chengdu, China
| | - Yuqian Cui
- Department of Urology, Medical Research Center, Department of Neurosurgery, The Third People’s Hospital of Chengdu, The Affiliated Hospital of Southwest Jiaotong University, The Second Chengdu Hospital Affiliated to Chongqing Medical University, Chengdu, China
| | - Xuerui Chen
- Department of Urology, Medical Research Center, Department of Neurosurgery, The Third People’s Hospital of Chengdu, The Affiliated Hospital of Southwest Jiaotong University, The Second Chengdu Hospital Affiliated to Chongqing Medical University, Chengdu, China
| | - Xu Su
- Department of Urology, Medical Research Center, Department of Neurosurgery, The Third People’s Hospital of Chengdu, The Affiliated Hospital of Southwest Jiaotong University, The Second Chengdu Hospital Affiliated to Chongqing Medical University, Chengdu, China
- College of Medicine, Southwest Jiaotong University, Chengdu, China
| | - Hui Zhuo
- Department of Urology, Medical Research Center, Department of Neurosurgery, The Third People’s Hospital of Chengdu, The Affiliated Hospital of Southwest Jiaotong University, The Second Chengdu Hospital Affiliated to Chongqing Medical University, Chengdu, China
| | - Liangbin Lin
- Department of Urology, Medical Research Center, Department of Neurosurgery, The Third People’s Hospital of Chengdu, The Affiliated Hospital of Southwest Jiaotong University, The Second Chengdu Hospital Affiliated to Chongqing Medical University, Chengdu, China
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4
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Yuming Z, Ruqi T, Gershwin ME, Xiong M. Autoimmune Hepatitis: Pathophysiology. Clin Liver Dis 2024; 28:15-35. [PMID: 37945156 DOI: 10.1016/j.cld.2023.06.003] [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] [Indexed: 11/12/2023]
Abstract
Genome-wide association analyses suggest that HLA genes including HLA-DRB*0301, HLA-DRB*0401, and HLA-B*3501 as well as non-HLA genes including CD28/CTLA4/ICOS and SYNPR increased AIH susceptibility. The destruction of hepatocytes is the result of the imbalance between proinflammatory cells and immunosuppressive cells, especially the imbalance between Tregs and Th17 cells. The microbiome in patients with AIH is decreased in diversity with a specific decline in Bifidobacterium and enrichment in Veillonella and Faecalibacterium. Recent evidence has demonstrated the pathogenic role of E. gallinarum and L.reuteri in inducing autoimmunity in the liver.
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Affiliation(s)
- Zhou Yuming
- Division of Gastroenterology and Hepatology, Key Laboratory of Gastroenterology and Hepatology, Ministry of Health, NHC Key Laboratory of Digestive Diseases, State Key Laboratory for Oncogenes and Related Genes, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai Institute of Digestive Disease, 145 Middle Shandong Road, Shanghai, China
| | - Tang Ruqi
- Division of Gastroenterology and Hepatology, Key Laboratory of Gastroenterology and Hepatology, Ministry of Health, NHC Key Laboratory of Digestive Diseases, State Key Laboratory for Oncogenes and Related Genes, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai Institute of Digestive Disease, 145 Middle Shandong Road, Shanghai, China
| | - Merrill Eric Gershwin
- Division of Rheumatology, Department of Medicine, Allergy and Clinical Immunology, University of California at Davis, 451 Health Sciences Drive, Suite 6510, Davis, CA 95616, USA.
| | - Ma Xiong
- Division of Gastroenterology and Hepatology, Key Laboratory of Gastroenterology and Hepatology, Ministry of Health, NHC Key Laboratory of Digestive Diseases, State Key Laboratory for Oncogenes and Related Genes, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai Institute of Digestive Disease, 145 Middle Shandong Road, Shanghai, China; Institute of Aging & Tissue Regeneration, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.
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5
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Centa M, Thermidor C, Fiel MI, Alexandropoulos K. Profiling of mouse and human liver diseases identifies targets for therapeutic treatment of autoimmune hepatitis. Clin Immunol 2023; 256:109807. [PMID: 37821072 DOI: 10.1016/j.clim.2023.109807] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Accepted: 10/07/2023] [Indexed: 10/13/2023]
Abstract
Autoimmune hepatitis (AIH), primary sclerosing cholangitis (PSC), and non-alcoholic steatohepatitis (NASH) are chronic liver diseases (CLDs) of distinct etiologies that represent a public health risk with limited therapeutic options. A common feature among CLDs is an aggressive T cell response resulting in destruction of liver tissue and fibrosis. Here, we assessed the presence and nature of T cell inflammation in late-stage human AIH, PSC and NASH and examined whether targeting the T cell response can improve disease pathology in a mouse model (Traf6ΔTEC) of spontaneous AIH. T cell infiltration and ensuing inflammatory pathways were present in human AIH and PSC and to a lesser extent in NASH. However, we observed qualitative differences in infiltrating T cell subsets and upregulation of inflammatory pathways among these diseases, while mouse and human AIH exhibited similar immunogenic signatures. While gene expression profiles differed among diseases, we identified 52 genes commonly upregulated across all diseases that included the JAK3 tyrosine kinase. Therapeutic targeting of chronic AIH with the JAK inhibitor tofacitinib reduced hepatic T cell infiltration, AIH histopathology and associated immune parameters in treated Traf6ΔTEC mice. Our results indicate that targeting T cell responses in established hepatic autoimmune inflammation is a feasible strategy for developing novel therapeutic approaches to treat AIH and possibly other CLDs irrespective of etiology.
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Affiliation(s)
- Monica Centa
- Department of Medicine, Division of Clinical Immunology, Division of Liver Diseases, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Christelle Thermidor
- Department of Medicine, Division of Clinical Immunology, Division of Liver Diseases, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Maria Isabel Fiel
- Department of Pathology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Konstantina Alexandropoulos
- Department of Medicine, Division of Clinical Immunology, Division of Liver Diseases, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
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6
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Lagou MK, Karagiannis GS. Obesity-induced thymic involution and cancer risk. Semin Cancer Biol 2023; 93:3-19. [PMID: 37088128 DOI: 10.1016/j.semcancer.2023.04.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 04/19/2023] [Accepted: 04/20/2023] [Indexed: 04/25/2023]
Abstract
Declining thymic functions associated either with old age (i.e., age-related thymic involution), or with acute involution as a result of stress, infectious disease, or cytoreductive therapies (e.g., chemotherapy/radiotherapy), have been associated with cancer development. A key mechanism underlying such increased cancer risk is the thymus-dependent debilitation of adaptive immunity, which is responsible for orchestrating immunoediting mechanisms and tumor immune surveillance. In the past few years, a blooming set of evidence has intriguingly linked obesity with cancer development and progression. The majority of such studies has focused on obesity-driven chronic inflammation, steroid/sex hormone and adipokine production, and hyperinsulinemia, as principal factors affecting the tumor microenvironment and driving the development of primary malignancy. However, experimental observations about the negative impact of obesity on T cell development and maturation have existed for more than half a century. Here, we critically discuss the molecular and cellular mechanisms of obesity-driven thymic involution as a previously underrepresented intermediary pathology leading to cancer development and progression. This knowledge could be especially relevant in the context of childhood obesity, because impaired thymic function in young individuals leads to immune system abnormalities, and predisposes to various pediatric cancers. A thorough understanding behind the molecular and cellular circuitries governing obesity-induced thymic involution could therefore help towards the rationalized development of targeted thymic regeneration strategies for obese individuals at high risk of cancer development.
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Affiliation(s)
- Maria K Lagou
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY, USA; Tumor Microenvironment of Metastasis Program, Albert Einstein Cancer Center, Bronx, NY, USA
| | - George S Karagiannis
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY, USA; Tumor Microenvironment of Metastasis Program, Albert Einstein Cancer Center, Bronx, NY, USA; Cancer Dormancy and Tumor Microenvironment Institute, Albert Einstein College of Medicine, Bronx, NY, USA; Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, NY, USA; Integrated Imaging Program for Cancer Research, Albert Einstein College of Medicine, Bronx, NY, USA.
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7
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Liu G, Zhang Y, Han S, Zhuang W, Lv J, Han M, Xie L, Jiang X, Wang C, Saimaier K, Shen J, Du C. TPN10466 ameliorates Concanavalin A-induced autoimmune hepatitis in mice via inhibiting ERK/JNK/p38 signaling pathway. Eur J Immunol 2023; 53:e2250100. [PMID: 36648433 DOI: 10.1002/eji.202250100] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 11/30/2022] [Accepted: 01/16/2023] [Indexed: 01/18/2023]
Abstract
Autoimmune hepatitis (AIH) eventually progresses to liver fibrosis, cirrhosis, and even hepatocellular carcinoma, causing irreversible damage to the liver. Concanavalin A-induced hepatitis in mice is a well-established model with pathophysiology similar to that of immune-mediated liver injury in human viral and autoimmune hepatitis, and it has been widely used to explore the pathogenesis and clinical treatment of human immune hepatitis. Artemisinin has been shown to exhibit anti-inflammatory effects through unclear mechanisms. In this study, we aimed to assess the effect of the artemisinin derivative TPN10466 on AIH. In vitro studies showed that TPN10466 dose dependently inhibited the percentage of IFN-γ-producing T cells. Further studies showed that TPN10466 attenuated the disease severity of AIH by downregulating the ability of lymphocytes to secrete IFN-γ and by reducing lymphocyte number in the liver. In addition, we found that TPN10466 treatment reduced T-cell responses by inhibiting JNK, ERK, and p38 pathways. In conclusion, our work suggests that TPN10466 provides protection against the autoimmune disease AIH by suppressing the inflammatory response of T cells, suggesting that TPN10466 may be a promising potential agent for the treatment of AIH.
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Affiliation(s)
- Guangyu Liu
- Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration of Ministry of Education, Orthopaedic Department of Tongji Hospital, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Yan Zhang
- University of Chinese Academy of Sciences, Beijing, China
- Xinjiang Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Urumqi, China
| | - Sansheng Han
- Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration of Ministry of Education, Orthopaedic Department of Tongji Hospital, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Wei Zhuang
- Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration of Ministry of Education, Orthopaedic Department of Tongji Hospital, School of Life Sciences and Technology, Tongji University, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
- Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Jie Lv
- Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration of Ministry of Education, Orthopaedic Department of Tongji Hospital, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Mengyao Han
- Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration of Ministry of Education, Orthopaedic Department of Tongji Hospital, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Ling Xie
- Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration of Ministry of Education, Orthopaedic Department of Tongji Hospital, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Xiangrui Jiang
- University of Chinese Academy of Sciences, Beijing, China
- CAS Key Laboratory for Receptor Research, Shanghai Institute of Materia, Medica, Chinese Academy of Sciences, Shanghai, China
| | - Chun Wang
- Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration of Ministry of Education, Orthopaedic Department of Tongji Hospital, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Kaidireya Saimaier
- Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration of Ministry of Education, Orthopaedic Department of Tongji Hospital, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Jingshan Shen
- University of Chinese Academy of Sciences, Beijing, China
- CAS Key Laboratory for Receptor Research, Shanghai Institute of Materia, Medica, Chinese Academy of Sciences, Shanghai, China
| | - Changsheng Du
- Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration of Ministry of Education, Orthopaedic Department of Tongji Hospital, School of Life Sciences and Technology, Tongji University, Shanghai, China
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Lapierre P, Alvarez F. Type 2 autoimmune hepatitis: Genetic susceptibility. Front Immunol 2022; 13:1025343. [PMID: 36248826 PMCID: PMC9556705 DOI: 10.3389/fimmu.2022.1025343] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Accepted: 09/14/2022] [Indexed: 11/13/2022] Open
Abstract
Two types of autoimmune hepatitis (AIH) are recognized; AIH-1 is characterized by the presence of anti-nuclear and/or anti-smooth muscle autoantibodies, while AIH-2 is associated with the presence of anti-Liver kidney microsome and/or anti-Liver Cytosol antibodies. The autoantigens targeted by AIH-2 autoantibodies are the cytochrome P450 2D6 and Formiminotransferase-cyclodeaminase for anti-LKM1 and anti-LC1 respectively. Both autoantigens are expressed in hepatocytes at higher levels than in any other cell type. Therefore, compared to AIH-1, the autoantigens targeted in AIH-2 are predominantly tissue-specific. Distinct clinical features are specific to AIH-2 compared to AIH-1, including diagnosis in younger patients (mean age 6.6 years), onset as fulminant hepatitis in very young patients (3 years of age or less), higher frequency in children than in adults and is frequently associated with extrahepatic T cell-mediated autoimmune diseases. AIH-2 is also often diagnosed in patients with primary immunodeficiency. AIH-2 is associated with specific HLA class II susceptibility alleles; DQB1*0201 is considered the main determinant of susceptibility while DRB1*07/DRB1*03 is associated with the type of autoantibody present. HLA DQB1*0201 is in strong linkage disequilibrium with both HLA DRB1*03 and DRB1*07. Interestingly, as in humans, MHC and non-MHC genes strongly influence the development of the disease in an animal model of AIH-2. Altogether, these findings suggest that AIH-2 incidence is likely dependent on specific genetic susceptibility factors combined with distinct environmental triggers.
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Affiliation(s)
- Pascal Lapierre
- Laboratoire d’hépatologie cellulaire, Centre de recherche du Centre hospitalier de l’Université de Montréal (CRCHUM), Montréal, QC, Canada
- Département de médecine, Université de Montréal, Montréal, QC, Canada
| | - Fernando Alvarez
- Service de gastroentérologie, hépatologie et nutrition, Centre Hospitalier Universitaire (CHU) Sainte-Justine, Montréal, QC, Canada
- Département de Pédiatrie, Université de Montréal, Montréal, QC, Canada
- *Correspondence: Fernando Alvarez,
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9
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Zhong T, Lei K, Lin X, Xie Z, Luo S, Zhou Z, Zhao B, Li X. Protein ubiquitination in T cell development. Front Immunol 2022; 13:941962. [PMID: 35990660 PMCID: PMC9386135 DOI: 10.3389/fimmu.2022.941962] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 07/11/2022] [Indexed: 11/26/2022] Open
Abstract
As an important form of posttranslational modification, protein ubiquitination regulates a wide variety of biological processes, including different aspects of T cell development and differentiation. During T cell development, thymic seeding progenitor cells (TSPs) in the thymus undergo multistep maturation programs and checkpoints, which are critical to build a functional and tolerant immune system. Currently, a tremendous amount of research has focused on the transcriptional regulation of thymocyte development. However, in the past few years, compelling evidence has revealed that the ubiquitination system also plays a crucial role in the regulation of thymocyte developmental programs. In this review, we summarize recent findings on the molecular mechanisms and cellular pathways that regulate thymocyte ubiquitination and discuss the roles of E3 ligases and deubiquitinating enzymes (DUBs) involved in these processes. Understanding how T cell development is regulated by ubiquitination and deubiquitination will not only enhance our understanding of cell fate determination via gene regulatory networks but also provide potential novel therapeutic strategies for treating autoimmune diseases and cancer.
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Affiliation(s)
| | | | | | | | | | | | - Bin Zhao
- *Correspondence: Bin Zhao, ; Xia Li,
| | - Xia Li
- *Correspondence: Bin Zhao, ; Xia Li,
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10
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Centa M, Weinstein EG, Clemente JC, Faith JJ, Fiel MI, Lyallpuri R, Herbin O, Alexandropoulos K. Impaired central tolerance induces changes in the gut microbiota that exacerbate autoimmune hepatitis. J Autoimmun 2022; 128:102808. [PMID: 35276587 PMCID: PMC8963681 DOI: 10.1016/j.jaut.2022.102808] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Revised: 02/10/2022] [Accepted: 02/19/2022] [Indexed: 12/18/2022]
Abstract
Medullary thymic epithelial cells (mTECs) induce T cell tolerance in the thymus through the elimination of self-reactive thymocytes. Commensal bacteria are also critical for shaping T cell responses in the gut and distal organs. We previously showed that mice depleted of mTECs (Traf6ΔTEC) generated autoreactive T cells and developed autoimmune hepatitis (AIH). In this report, we found that Toll-like receptor (TLR)-mediated microbial sensing on liver hematopoietic cells and the gut microbiota contributed to AIH development in Traf6ΔTEC mice. While adoptive transfer of thymic Traf6ΔTEC T cells in immune-deficient mice was sufficient for AIH development, colonization of germ-free mice with Traf6ΔTEC microbiota failed to induce AIH, suggesting that the gut microbiota contributes to but is not sufficient for AIH development. Microbiota-mediated exacerbation of AIH associated with increased numbers of hepatic Foxp3+ T cells and their increase was proportional to the degree of inflammation. The contribution of the gut microbiota to AIH development associated with an altered microbial signature whose composition was influenced by the qualitative nature of the thymic T cell compartment. These results suggest that aberrant selection of T cells in the thymus can induce changes in the gut microbiota that lead to exacerbation of organ-specific autoimmunity and AIH. Our results add to our understanding of the mechanisms of AIH development and create a platform towards developing novel therapeutic approaches for treating this disease.
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Affiliation(s)
- Monica Centa
- Department of Medicine, Division of Clinical Immunology, Division of Liver Diseases, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | | | - Jose C Clemente
- Department of Medicine, Division of Clinical Immunology, Division of Liver Diseases, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Jeremiah J Faith
- Department of Medicine, Division of Clinical Immunology, Division of Liver Diseases, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - M Isabel Fiel
- Department of Pathology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Robby Lyallpuri
- Department of Medicine, Division of Clinical Immunology, Division of Liver Diseases, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | | | - Konstantina Alexandropoulos
- Department of Medicine, Division of Clinical Immunology, Division of Liver Diseases, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
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11
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Terziroli Beretta-Piccoli B, Mieli-Vergani G, Vergani D. Autoimmmune hepatitis. Cell Mol Immunol 2022; 19:158-176. [PMID: 34580437 PMCID: PMC8475398 DOI: 10.1038/s41423-021-00768-8] [Citation(s) in RCA: 55] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2021] [Accepted: 08/29/2021] [Indexed: 02/06/2023] Open
Abstract
Autoimmune hepatitis (AIH) is a T-cell mediated, inflammatory liver disease affecting all ages and characterized by female preponderance, elevated serum transaminase and immunoglobulin G levels, positive circulating autoantibodies, and presence of interface hepatitis at liver histology. AIH type 1, affecting both adults and children, is defined by positive anti-nuclear and/or anti-smooth muscle antibodies, while type 2 AIH, affecting mostly children, is defined by positive anti-liver-kidney microsomal type 1 and/or anti-liver cytosol type 1 antibody. While the autoantigens of type 2 AIH are well defined, being the cytochrome P4502D6 (CYP2D6) and the formiminotransferase cyclodeaminase (FTCD), in type 1 AIH they remain to be identified. AIH-1 predisposition is conferred by possession of the MHC class II HLA DRB1*03 at all ages, while DRB1*04 predisposes to late onset disease; AIH-2 is associated with possession of DRB1*07 and DRB1*03. The majority of patients responds well to standard immunosuppressive treatment, based on steroid and azathioprine; second- and third-line drugs should be considered in case of intolerance or insufficient response. This review offers a comprehensive overview of pathophysiological and clinical aspects of AIH.
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Affiliation(s)
- Benedetta Terziroli Beretta-Piccoli
- Epatocentro Ticino & Facoltà di Scienze Biomediche, Università della Svizzera Italiana, Lugano, Switzerland.
- Institute for Research in Biomedicine, Bellinzona, Switzerland.
- King's College London Faculty of Life Sciences & Medicine at King's College Hospital, London, UK.
| | - Giorgina Mieli-Vergani
- King's College London Faculty of Life Sciences & Medicine at King's College Hospital, London, UK
- Paediatric Liver, GI and Nutrition Centre, MowatLabs, King's College Hospital, London, UK
| | - Diego Vergani
- King's College London Faculty of Life Sciences & Medicine at King's College Hospital, London, UK
- Institute of Liver Studies, MowatLabs, King's College Hospital, London, UK
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12
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Liu J, Ma Z, Li H, Li X. Chinese medicine in the treatment of autoimmune hepatitis: Progress and future opportunities. Animal Model Exp Med 2022; 5:95-107. [PMID: 35263512 PMCID: PMC9043711 DOI: 10.1002/ame2.12201] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 12/31/2021] [Accepted: 01/06/2022] [Indexed: 12/22/2022] Open
Abstract
Autoimmune hepatitis (AIH) is a chronic inflammatory liver disease occurring in individuals of all ages with a higher incidence in females and characterized by hypergammaglobulinemia, elevated serum autoantibodies and histological features of interface hepatitis. AIH pathogenesis remains obscure and still needs in‐depth study, which is likely associated with genetic susceptibility and the loss of immune homeostasis. Steroids alone and in combination with other immunosuppressant agents are the primary choices of AIH treatment in the clinic, whereas, in some cases, severe adverse effects and disease relapse may occur. Chinese medicine used for the treatment of AIH has proven its merits over many years and is well tolerated. To better understand the pathogenesis of AIH and to evaluate the efficacy of novel therapies, several animal models have been generated to recapitulate the immune microenvironment of patients with AIH. In the current review, we summarize recent advances in the study of animal models for AIH and their application in pharmacological research of Chinese medicine‐based therapies and also discuss current limitations. This review aims to provide novel insights into the discovery of Chinese medicine‐originated therapies for AIH using cutting‐edge animal models.
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Affiliation(s)
- Jia Liu
- School of Life SciencesBeijing University of Chinese MedicineBeijingChina
| | - Zhi Ma
- School of Life SciencesBeijing University of Chinese MedicineBeijingChina
| | - Han Li
- School of Life SciencesBeijing University of Chinese MedicineBeijingChina
| | - Xiaojiaoyang Li
- School of Life SciencesBeijing University of Chinese MedicineBeijingChina
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13
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Petrova T, Bennett K, Nanda S, Strickson S, Scudamore CL, Prescott AR, Cohen P. Why are the phenotypes of TRAF6 knock-in and TRAF6 knock-out mice so different? PLoS One 2022; 17:e0263151. [PMID: 35157702 PMCID: PMC8843210 DOI: 10.1371/journal.pone.0263151] [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: 07/29/2021] [Accepted: 01/12/2022] [Indexed: 11/30/2022] Open
Abstract
The expression of TNF-Receptor Associated Factor 6 (TRAF6) is essential for many physiological processes. Here we studied the phenotype of TRAF6[L74H] knock-in mice which are devoid of TRAF6 E3 ligase activity in every cell of the body, but express normal levels of the TRAF6 protein. Remarkably, TRAF6[L74H] mice have none of the phenotypes seen in TRAF6 KO mice. Instead TRAF6[L74H] mice display an entirely different phenotype, exhibiting autoimmunity, and severe inflammation of the skin and modest inflammation of the liver and lungs. Similar to mice with a Treg-specific knockout of TRAF6, or mice devoid of TRAF6 in all T cells, the CD4+ and CD8+ T cells in the spleen and lymph nodes displayed an activated effector memory phenotype with CD44high/CD62Llow expression on the cell surface. In contrast, T cells from WT mice exhibited the CD44low/CD62Lhigh phenotype characteristic of naïve T cells. The onset of autoimmunity and autoinflammation in TRAF6[L74H] mice (two weeks) was much faster than in mice with a Treg-specific knockout of TRAF6 or lacking TRAF6 expression in all T cells (2-3 months) and we discuss whether this may be caused by secondary inflammation of other tissues. The distinct phenotypes of mice lacking TRAF6 expression in all cells appears to be explained by their inability to signal via TNF Receptor Superfamily members, which does not seem to be impaired significantly in TRAF6[L74H] mice.
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Affiliation(s)
- Tsvetana Petrova
- MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Kyle Bennett
- MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee, United Kingdom
- Division of Cell Signalling, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Sambit Nanda
- MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Sam Strickson
- MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | | | - Alan R. Prescott
- Dundee Imaging Facility and Division of Cell Signalling and Immunology, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Philip Cohen
- MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee, United Kingdom
- * E-mail:
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14
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Sirbe C, Simu G, Szabo I, Grama A, Pop TL. Pathogenesis of Autoimmune Hepatitis-Cellular and Molecular Mechanisms. Int J Mol Sci 2021; 22:13578. [PMID: 34948375 PMCID: PMC8703580 DOI: 10.3390/ijms222413578] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2021] [Revised: 12/09/2021] [Accepted: 12/14/2021] [Indexed: 02/05/2023] Open
Abstract
Pediatric autoimmune liver disorders include autoimmune hepatitis (AIH), autoimmune sclerosing cholangitis (ASC), and de novo AIH after liver transplantation. AIH is an idiopathic disease characterized by immune-mediated hepatocyte injury associated with the destruction of liver cells, causing inflammation, liver failure, and fibrosis, typically associated with autoantibodies. The etiology of AIH is not entirely unraveled, but evidence supports an intricate interaction among genetic variants, environmental factors, and epigenetic modifications. The pathogenesis of AIH comprises the interaction between specific genetic traits and molecular mimicry for disease development, impaired immunoregulatory mechanisms, including CD4+ T cell population and Treg cells, alongside other contributory roles played by CD8+ cytotoxicity and autoantibody production by B cells. These findings delineate an intricate pathway that includes gene to gene and gene to environment interactions with various drugs, viral infections, and the complex microbiome. Epigenetics emphasizes gene expression through hereditary and reversible modifications of the chromatin architecture without interfering with the DNA sequence. These alterations comprise DNA methylation, histone transformations, and non-coding small (miRNA) and long (lncRNA) RNA transcriptions. The current first-line therapy comprises prednisolone plus azathioprine to induce clinical and biochemical remission. Further understanding of the cellular and molecular mechanisms encountered in AIH may depict their impact on clinical aspects, detect biomarkers, and guide toward novel, effective, and better-targeted therapies with fewer side effects.
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Affiliation(s)
- Claudia Sirbe
- 2nd Pediatric Discipline, Department of Mother and Child, “Iuliu Hatieganu” University of Medicine and Pharmacy, 400012 Cluj-Napoca, Romania; (C.S.); (T.L.P.)
- 2nd Pediatric Clinic, Emergency Clinical Hospital for Children, 400177 Cluj-Napoca, Romania
| | - Gelu Simu
- Cardiology Department, “Iuliu Hatieganu” University of Medicine and Pharmacy, 400012 Cluj-Napoca, Romania;
- Cardiology Department, Rehabilitation Hospital, 400066 Cluj-Napoca, Romania
| | - Iulia Szabo
- Department of Rheumatology, “Iuliu Hatieganu” University of Medicine and Pharmacy, 400012 Cluj-Napoca, Romania;
| | - Alina Grama
- 2nd Pediatric Discipline, Department of Mother and Child, “Iuliu Hatieganu” University of Medicine and Pharmacy, 400012 Cluj-Napoca, Romania; (C.S.); (T.L.P.)
- 2nd Pediatric Clinic, Emergency Clinical Hospital for Children, 400177 Cluj-Napoca, Romania
| | - Tudor Lucian Pop
- 2nd Pediatric Discipline, Department of Mother and Child, “Iuliu Hatieganu” University of Medicine and Pharmacy, 400012 Cluj-Napoca, Romania; (C.S.); (T.L.P.)
- 2nd Pediatric Clinic, Emergency Clinical Hospital for Children, 400177 Cluj-Napoca, Romania
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15
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Vuerich M, Wang N, Kalbasi A, Graham JJ, Longhi MS. Dysfunctional Immune Regulation in Autoimmune Hepatitis: From Pathogenesis to Novel Therapies. Front Immunol 2021; 12:746436. [PMID: 34650567 PMCID: PMC8510512 DOI: 10.3389/fimmu.2021.746436] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Accepted: 09/10/2021] [Indexed: 12/20/2022] Open
Abstract
Autoimmune hepatitis (AIH) is a chronic inflammatory disorder characterized by hypergammaglobulinemia, presence of serum autoantibodies and histological features of interface hepatitis. AIH therapeutic management still relies on the administration of corticosteroids, azathioprine and other immunosuppressants like calcineurin inhibitors and mycophenolate mofetil. Withdrawal of immunosuppression often results in disease relapse, and, in some cases, therapy is ineffective or associated with serious side effects. Understanding the mechanisms underlying AIH pathogenesis is therefore of paramount importance to develop more effective and well tolerated agents capable of restoring immunotolerance to liver autoantigens. Imbalance between effector and regulatory cells permits liver damage perpetuation and progression in AIH. Impaired expression and regulation of CD39, an ectoenzyme key to immunotolerance maintenance, have been reported in Tregs and effector Th17-cells derived from AIH patients. Interference with these altered immunoregulatory pathways may open new therapeutic avenues that, in addition to limiting aberrant inflammatory responses, would also reconstitute immune homeostasis. In this review, we highlight the most recent findings in AIH immunopathogenesis and discuss how these could inform and direct the development of novel therapeutic tools.
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Affiliation(s)
- Marta Vuerich
- Department of Anesthesia, Critical Care & Pain Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States
| | - Na Wang
- Department of Anesthesia, Critical Care & Pain Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States.,Department of Hematology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, China.,School of Medicine, Shandong University, Jinan, China
| | - Ahmadreza Kalbasi
- Department of Anesthesia, Critical Care & Pain Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States
| | - Jonathon J Graham
- Department of Anesthesia, Critical Care & Pain Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States
| | - Maria Serena Longhi
- Department of Anesthesia, Critical Care & Pain Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States
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16
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Liang Z, Zhang Q, Dong X, Zhang Z, Wang H, Zhang J, Zhao Y. mTORC2 negatively controls the maturation process of medullary thymic epithelial cells by inhibiting the LTβR/RANK-NF-κB axis. J Cell Physiol 2021; 236:4725-4737. [PMID: 33269476 DOI: 10.1002/jcp.30192] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 11/06/2020] [Accepted: 11/20/2020] [Indexed: 01/01/2023]
Abstract
The differentiation of mature medullary thymic epithelial cells (mTECs) is critical for the induction of central immune tolerance. Although the critical effect of mechanistic target of rapamycin complex 1 (mTORC1) in shaping mTEC differentiation has been studied, the regulatory role of mTORC2 in the differentiation and maturation of mTECs is poorly understood. We herein reported that TEC-specific ablation of a rapamycin-insensitive companion of mTOR (RICTOR), a key component of mTORC2, significantly decreased the thymus size and weight, the total cell number of TECs, and the cell number of mTECs with a smaller degree of reduced cortical thymic epithelial cells. Interestingly, RICTOR deficiency significantly accelerated the mTEC maturation process, as indicated by the increased ratios of mature mTECs (MHCIIhi , CD80+ , and Aire+ ) to immature mTECs (MHCIIlo , CD80- , and Aire- ) in Rictor-deficient mice. The RNA-sequencing assays showed that the upregulated nuclear factor-κB (NF-κB) signaling pathway in Rictor-deficient mTECs was one of the obviously altered pathways compared with wild-type mTECs. Our studies further showed that Rictor-deficient mTECs exhibited upregulated expression of receptor activator of NF-κB (RANK) and lymphotoxin β receptor (LTβR), as well as increased activity of canonical and noncanonical NF-κB signaling pathways as determined by ImageStream and Simple Western. Finally, our results showed that inhibition of NF-κB signaling pathways could partially reverse the accelerated maturation of mTECs in Rictor conditional KO mice. Thus, mTORC2 negatively controls the kinetics of the mTEC maturation process by inhibiting the LTβR/RANK-NF-κB signal axis.
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Affiliation(s)
- Zhanfeng Liang
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Qian Zhang
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Xue Dong
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Zhaoqi Zhang
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Hongxia Wang
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- Laboratory Medicine Center, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, China
| | - Jiayu Zhang
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yong Zhao
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
- Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing, China
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17
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Preti M, Schlott L, Lübbering D, Krzikalla D, Müller AL, Schuran FA, Poch T, Schakat M, Weidemann S, Lohse AW, Weiler-Normann C, Sebode M, Schwinge D, Schramm C, Carambia A, Herkel J. Failure of thymic deletion and instability of autoreactive Tregs drive autoimmunity in immune-privileged liver. JCI Insight 2021; 6:141462. [PMID: 33600378 PMCID: PMC8026180 DOI: 10.1172/jci.insight.141462] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 02/17/2021] [Indexed: 12/11/2022] Open
Abstract
The liver is an immune-privileged organ that can deactivate autoreactive T cells. Yet in autoimmune hepatitis (AIH), autoreactive T cells can defy hepatic control and attack the liver. To elucidate how tolerance to self-antigens is lost during AIH pathogenesis, we generated a spontaneous mouse model of AIH, based on recognition of an MHC class II–restricted model peptide in hepatocytes by autoreactive CD4+ T cells. We found that the hepatic peptide was not expressed in the thymus, leading to deficient thymic deletion and resulting in peripheral abundance of autoreactive CD4+ T cells. In the liver, autoreactive CD4+ effector T cells accumulated within portal ectopic lymphoid structures and maturated toward pathogenic IFN-γ and TNF coproducing cells. Expansion and pathogenic maturation of autoreactive effector T cells was enabled by a selective increase of plasticity and instability of autoantigen-specific Tregs but not of nonspecific Tregs. Indeed, antigen-specific Tregs were reduced in frequency and manifested increased IL-17 production, reduced epigenetic demethylation, and reduced expression of Foxp3. As a consequence, autoantigen-specific Tregs had a reduced suppressive capacity, as compared with that of nonspecific Tregs. In conclusion, loss of tolerance and the pathogenesis of AIH were enabled by combined failure of thymic deletion and peripheral regulation.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | - Christoph Schramm
- Department of Medicine I.,Martin Zeitz Center for Rare Diseases, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany
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18
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Assandri R, Montanelli A. Acute severe autoimmune hepatitis with anti-rods and rings autoantibodies; literature first evidence. GASTROENTEROLOGY AND HEPATOLOGY FROM BED TO BENCH 2021; 14:89-94. [PMID: 33868616 PMCID: PMC8035537] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Accepted: 12/22/2020] [Indexed: 10/28/2022]
Abstract
Autoimmune hepatitis (AIH) was defined as a progressive, chronic inflammatory autoimmune liver disease (ALD). The diagnosis of AIH requires the presence of characteristic clinical and laboratory features, and the exclusion of other clinical conditions that cause chronic hepatitis and cirrhosis. AIH can have an acute onset that mimics an acute viral or toxic hepatitis or an acute severe (fulminant, ASF) presentation that satisfies criteria for acute liver. Guidelines from the European Association for the Study of Liver Diseases define ALF with absence of pre-existing liver disease, acute onset of ≤ 26 weeks, coagulopathy (international normalised ratio (INR) ≥ 1.5), and presence of hepatic encephalopathy (HE). In recent years, autoantibodies (Aab) targeting subcellular structures described as the rods and rings (R&R) pattern in HEp-2 ANA have been presented as a unique and particular case of Aab generation. These R&R structures are composed of inosine monophosphate dehydrogenase type 2 (IMPDH2), and their formation can be induced in vitro by several small-molecule inhibitors. Aab targeting these relatively unknown structures has been observed in Hepatitis C virus (HCV) patients who have undergone treatment with pegylated interferona/ ribavirin (IFN/RBV) therapy. We presented and characterized a case patient with R&R and SMA Aab in AIH (ASF, fatal, without liver transplantation). To the best of our knowledge, this is the first evidence described in the Literature. Our early experience showed the R&R circulating Aab in one patient with Primary Biliary Cholangitis. This work now demonstrates that R&R Aab can also be present in AIH case.
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Affiliation(s)
- Roberto Assandri
- Clinical Investigation Laboratory, ASST Crema, Crema, Cremona, Italy
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19
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Mechanism by which TRAF6 Participates in the Immune Regulation of Autoimmune Diseases and Cancer. BIOMED RESEARCH INTERNATIONAL 2020; 2020:4607197. [PMID: 33294443 PMCID: PMC7714562 DOI: 10.1155/2020/4607197] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 11/06/2020] [Accepted: 11/17/2020] [Indexed: 11/24/2022]
Abstract
Tumor necrosis factor (TNF) receptor-associated factor 6 (TRAF6), an E3 ubiquitin ligase, is a signal transduction molecule shared by the interleukin-1 receptor (IL-1R)/Toll-like receptor (TLR) family and the TNFR superfamily. TRAF6 has a unique TRAF domain and RING finger domain that mediate intracellular signaling events. In the immune system, TRAF6-mediated signaling has been shown to be critical for the development, homeostasis, and activation of a variety of immune cells, including B cells, T cells, dendritic cells, and macrophages. Although the pathogenesis and etiology of autoimmune diseases and cancer are not fully understood, it is worth noting that existing studies have shown that TRAF6 is involved in the pathogenesis and development of a variety of these diseases. Herein, we reviewed the role of TRAF6 in certain immune cells, as well as the function and potential effect of TRAF6 in autoimmune diseases and cancer. Our review indicates that TRAF6 may be a novel target for autoimmune diseases and cancer.
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20
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Identification and characterization of dynamically regulated hepatitis-related genes in a concanavalin A-induced liver injury model. Aging (Albany NY) 2020; 12:23187-23199. [PMID: 33221747 PMCID: PMC7746381 DOI: 10.18632/aging.104089] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 08/31/2020] [Indexed: 12/11/2022]
Abstract
Background: Concanavalin A (ConA)-induced liver damage of mice is a well-established murine model mimicking the human autoimmune hepatitis (AIH). However, the pathogenic genes of the liver injury remain to be revealed. Methods: Using time-series liver transcriptome, top dynamic genes were inferred from a set of segmented regression models, and cross-checked by weighted correlation network analysis (WGCNA). AIH murine models created by ConA were used to verify the in vivo effect of these genes. Results: We identified 115 top dynamic genes, of which most were overlapped with the hub genes determined by WGCNA. The expression of several top dynamic genes including Cd63, Saa3, Slc10a1, Nrxn1, Ugt2a3, were verified in vivo. Further, Cluster determinant 63 (Cd63) knockdown in mice treated with ConA showed significantly less liver pathology and inflammation as well as higher survival rates than the corresponding controls. Conclusion: We have identified the top dynamic genes related to the process of acute liver injury, and highlighted a targeted strategy for Cd63 might have utility for the protection of hepatocellular damage.
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21
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Wang H, Feng X, Yan W, Tian D. Regulatory T Cells in Autoimmune Hepatitis: Unveiling Their Roles in Mouse Models and Patients. Front Immunol 2020; 11:575572. [PMID: 33117375 PMCID: PMC7575771 DOI: 10.3389/fimmu.2020.575572] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Accepted: 09/07/2020] [Indexed: 12/11/2022] Open
Abstract
Autoimmune hepatitis (AIH) is a severe and chronic liver disease, and its incidence has increased worldwide in recent years. Research into the pathogenesis of AIH remains limited largely owing to the lack of suitable mouse models. The concanavalin A (ConA) mouse model is a typical and well-established model used to investigate T cell-dependent liver injury. However, ConA-induced hepatitis is acute and usually disappears after 48 h; thus, it does not mimic the pathogenesis of AIH in the human body. Several studies have explored various AIH mouse models, but as yet there is no widely accepted and valid mouse model for AIH. Immunosuppression is the standard clinical therapy for AIH, but patient side effects and recurrence limit its use. Regulatory T cells (Tregs) play critical roles in the maintenance of immune homeostasis and in the prevention of autoimmune diseases, which may provide a potential therapeutic target for AIH therapy. However, the role of Tregs in AIH has not yet been clarified, partly because of difficulties in diagnosing AIH and in collecting patient samples. In this review, we discuss the studies related to Treg in various AIH mouse models and patients with AIH and provide some novel insights for this research area.
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Affiliation(s)
- Han Wang
- Department of Gastroenterology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xinxia Feng
- Department of Gastroenterology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Wei Yan
- Department of Gastroenterology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Dean Tian
- Department of Gastroenterology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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22
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Assis DN. Immunopathogenesis of Autoimmune Hepatitis. Clin Liver Dis (Hoboken) 2020; 15:129-132. [PMID: 32257125 PMCID: PMC7128031 DOI: 10.1002/cld.873] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Accepted: 08/12/2019] [Indexed: 02/04/2023] Open
Abstract
http://aasldpubs.onlinelibrary.wiley.com/hub/journal/10.1002/(ISSN)2046-2484/video/15-3-reading-assis a video presentation of this article http://aasldpubs.onlinelibrary.wiley.com/hub/journal/10.1002/(ISSN)2046-2484/video/15-3-interview-assis the interview with the author.
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Affiliation(s)
- David N. Assis
- Department of Medicine, Section of Digestive DiseasesYale School of MedicineNew HavenCT
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23
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Abstract
The generation of a functional T cell repertoire in the thymus is mainly orchestrated by thymic epithelial cells (TECs), which provide developing T cells with cues for their navigation, proliferation, differentiation and survival. The TEC compartment has been segregated historically into two major populations of medullary TECs and cortical TECs, which differ in their anatomical localization, molecular characteristics and functional roles. However, recent studies have shown that TECs are highly heterogeneous and comprise multiple subpopulations with distinct molecular and functional characteristics, including tuft cell-like or corneocyte-like phenotypes. Here, we review the most recent advances in our understanding of TEC heterogeneity from a molecular, functional and developmental perspective. In particular, we highlight the key insights that were recently provided by single-cell genomic technologies and in vivo fate mapping and discuss them in the context of previously published data.
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24
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Webb GJ, Hirschfield GM, Krawitt EL, Gershwin ME. Cellular and Molecular Mechanisms of Autoimmune Hepatitis. ANNUAL REVIEW OF PATHOLOGY-MECHANISMS OF DISEASE 2019; 13:247-292. [PMID: 29140756 DOI: 10.1146/annurev-pathol-020117-043534] [Citation(s) in RCA: 87] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Autoimmune hepatitis is an uncommon idiopathic syndrome of immune-mediated destruction of hepatocytes, typically associated with autoantibodies. The disease etiology is incompletely understood but includes a clear association with human leukocyte antigen (HLA) variants and other non-HLA gene variants, female sex, and the environment. Pathologically, there is a CD4+ T cell-rich lymphocytic inflammatory infiltrate with variable hepatocyte necrosis and subsequent hepatic fibrosis. Attempts to understand pathogenesis are informed by several monogenetic syndromes that may include autoimmune liver injury, by several drug and environmental agents that have been identified as triggers in a minority of cases, by human studies that point toward a central role for CD4+ effector and regulatory T cells, and by animal models of the disease. Nonspecific immunosuppression is the current standard therapy. Further understanding of the disease's cellular and molecular mechanisms may assist in the design of better-targeted therapies, aid the limitation of adverse effects from therapy, and inform individualized risk assessment and prognostication.
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Affiliation(s)
- G J Webb
- National Institute for Health Research Liver Biomedical Research Centre, Institute of Immunology and Immunotherapy, University of Birmingham, Birmingham B15 2TT, United Kingdom; ,
| | - G M Hirschfield
- National Institute for Health Research Liver Biomedical Research Centre, Institute of Immunology and Immunotherapy, University of Birmingham, Birmingham B15 2TT, United Kingdom; ,
| | - E L Krawitt
- Department of Medicine, University of Vermont, Burlington, Vermont 05405, USA; .,Department of Medicine, Dartmouth College, Hanover, New Hampshire 03755, USA
| | - M E Gershwin
- Division of Rheumatology, Allergy, and Clinical Immunology, School of Medicine, University of California, Davis, California 95817, USA;
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25
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Fujita Y, Tinoco R, Li Y, Senft D, Ronai ZA. Ubiquitin Ligases in Cancer Immunotherapy - Balancing Antitumor and Autoimmunity. Trends Mol Med 2019; 25:428-443. [PMID: 30898473 DOI: 10.1016/j.molmed.2019.02.002] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 02/05/2019] [Accepted: 02/07/2019] [Indexed: 12/25/2022]
Abstract
Considerable progress has been made in understanding the contribution of E3 ubiquitin ligases to health and disease, including the pathogenesis of immunological disorders. Ubiquitin ligases exert exquisite spatial and temporal control over protein stability and function, and are thus crucial for the regulation of both innate and adaptive immunity. Given that immune responses can be both detrimental (autoimmunity) and beneficial (antitumor immunity), it is vital to understand how ubiquitin ligases maintain immunological homeostasis. Such knowledge could reveal novel mechanisms underlying immune regulation and identify new therapeutic approaches to enhance antitumor immunity and safeguard against autoimmunity.
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Affiliation(s)
- Yu Fujita
- National Cancer Institute (NCI) Cancer Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA; Present address: Division of Respiratory Medicine, Department of Internal Medicine, Jikei University School of Medicine, Tokyo 105-8461, Japan
| | - Roberto Tinoco
- Department of Molecular Biology and Biochemistry, University of California Irvine, Irvine, CA 92697, USA
| | - Yan Li
- National Cancer Institute (NCI) Cancer Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA
| | - Daniela Senft
- Research Unit Apoptosis in Hematopoietic Stem Cells, Helmholtz Zentrum München, German Research Center for Environmental Health (HMGU), Munich, Germany
| | - Ze'ev A Ronai
- National Cancer Institute (NCI) Cancer Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA.
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Zhao Y, Li Y, Zhao D, Zhang H, Liu Y, Liao H, Zhang Y, Yan H. Fumarate hydratase-specific T cell response in Chinese patients with autoimmune hepatitis. Clin Res Hepatol Gastroenterol 2018; 42:339-346. [PMID: 29610041 DOI: 10.1016/j.clinre.2017.12.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Accepted: 12/19/2017] [Indexed: 02/04/2023]
Abstract
PURPOSE Fumarate hydratase (FH) is expressed in the serum of patients with autoimmune hepatitis (AIH). The specific involvement of FH-specific T cell response is currently unknown. The aim of the study was to assess the frequency and clinical significance of FH-specific T cell response in AIH. METHODS This was a prospective study of 42 consecutive patients admitted to the clinical study center of autoimmune liver disease of our Hospital, Capital Medical University (China) between January 2011 and December 2014. PBMCs were collected and the FH-specific T cell response was detected by Elispot. Cytokines and antibody responses were assessed. RESULTS Among the 42 AIH patients, 57.1% showed a positive response to FH peptides. The difference in FH-specific T cell response frequency among AIH patients and control groups was significant (P<0.001). The FH peptides induced the secretion of CD4+ and CD8+ T cells. The FH-specific T cell response in patients with active disease was stronger than in those with remission (P=0.0283). FH-specific T cell response in patients with active disease showed a positive association with ALT (r=0.4712, P=0.0098) and AST (r=0.3924, P=0.0352) levels. The magnitude of the FH-specific T cell response correlated with the HAI score (r=0.7290, P=0.0047) and anti-FH titer (r=0.6457, P=0.0093). CONCLUSION FH-specific T cell response may be detected in the blood of patients with AIH and seems to be associated with AIH disease progression. FH-specific T cell response could be a pathogenic cause of AIH.
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Affiliation(s)
- Yan Zhao
- Center for clinical laboratory, Beijing You'An Hospital, Capital Medical University, 100069 Beijing, China
| | - Yanli Li
- Beijing University of Chinese Medicine Third Affiliated Hospital, Beijing, China
| | - Dantong Zhao
- Center for clinical laboratory, Beijing You'An Hospital, Capital Medical University, 100069 Beijing, China
| | - Haiping Zhang
- Center for clinical laboratory, Beijing You'An Hospital, Capital Medical University, 100069 Beijing, China
| | - Yanmin Liu
- Study Centre of Autoimmune liver disease, Beijing You'An Hospital, Capital Medical University, 100069 Beijing, China
| | - Huiyu Liao
- Study Centre of Autoimmune liver disease, Beijing You'An Hospital, Capital Medical University, 100069 Beijing, China
| | - Yonghong Zhang
- Interventional therapy center, Beijing You'An Hospital, Capital Medical University, 100069 Beijing, China.
| | - Huiping Yan
- Center for clinical laboratory, Beijing You'An Hospital, Capital Medical University, 100069 Beijing, China.
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Matsumoto R, Dainichi T, Tsuchiya S, Nomura T, Kitoh A, Hayden MS, Ishii KJ, Tanaka M, Honda T, Egawa G, Otsuka A, Nakajima S, Sakurai K, Nakano Y, Kobayashi T, Sugimoto Y, Kabashima K. Epithelial TRAF6 drives IL-17-mediated psoriatic inflammation. JCI Insight 2018; 3:121175. [PMID: 30089718 DOI: 10.1172/jci.insight.121175] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Accepted: 06/21/2018] [Indexed: 12/25/2022] Open
Abstract
Epithelial cells are the first line of defense against external dangers, and contribute to induction of adaptive immunity including Th17 responses. However, it is unclear whether specific epithelial signaling pathways are essential for the development of robust IL-17-mediated immune responses. In mice, the development of psoriatic inflammation induced by imiquimod required keratinocyte TRAF6. Conditional deletion of TRAF6 in keratinocytes abrogated dendritic cell activation, IL-23 production, and IL-17 production by γδ T cells at the imiquimod-treated sites. In contrast, hapten-induced contact hypersensitivity and papain-induced IgE production were not affected by loss of TRAF6. Loss of psoriatic inflammation was not solely due to defective imiquimod sensing, as subcutaneous administration of IL-23 restored IL-17 production but did not reconstitute psoriatic pathology in the mutant animals. Thus, TRAF6 was required for the full development of IL-17-mediated inflammation. Therefore, epithelial TRAF6 signaling plays an essential role in both triggering and propagating IL-17-mediated psoriatic inflammation.
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Affiliation(s)
- Reiko Matsumoto
- Department of Dermatology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Teruki Dainichi
- Department of Dermatology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Soken Tsuchiya
- Department of Pharmaceutical Biochemistry, Kumamoto University Faculty of Life Sciences, Kumamoto, Japan
| | - Takashi Nomura
- Department of Dermatology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Akihiko Kitoh
- Department of Dermatology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Matthew S Hayden
- Section of Dermatology, Department of Surgery, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, USA
| | - Ken J Ishii
- Laboratory of Adjuvant Innovation, National Institutes of Biomedical Innovation, Health and Nutrition, Osaka, Japan.,Laboratory of Vaccine Science, WPI Immunology Frontier Research Center, Osaka University, Osaka, Japan
| | - Mayuri Tanaka
- Laboratory of Adjuvant Innovation, National Institutes of Biomedical Innovation, Health and Nutrition, Osaka, Japan.,Laboratory of Vaccine Science, WPI Immunology Frontier Research Center, Osaka University, Osaka, Japan
| | - Tetsuya Honda
- Department of Dermatology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Gyohei Egawa
- Department of Dermatology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Atsushi Otsuka
- Department of Dermatology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Saeko Nakajima
- Department of Dermatology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Kenji Sakurai
- Department of Dermatology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Yuri Nakano
- Department of Dermatology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Takashi Kobayashi
- Department of Infectious Disease Control, Faculty of Medicine, Oita University, Oita, Japan
| | - Yukihiko Sugimoto
- Department of Pharmaceutical Biochemistry, Kumamoto University Faculty of Life Sciences, Kumamoto, Japan
| | - Kenji Kabashima
- Department of Dermatology, Kyoto University Graduate School of Medicine, Kyoto, Japan.,Singapore Immunology Network (SIgN) and Institute of Medical Biology, Agency for Science, Technology and Research (A*STAR), Biopolis, Singapore
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28
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Pinto AI, Smith J, Kissack MR, Hogg KG, Green EA. Thymic B Cell-Mediated Attack of Thymic Stroma Precedes Type 1 Diabetes Development. Front Immunol 2018; 9:1281. [PMID: 29930554 PMCID: PMC5999731 DOI: 10.3389/fimmu.2018.01281] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Accepted: 05/22/2018] [Indexed: 01/11/2023] Open
Abstract
Type 1 diabetes (T1D) results from a coordinated autoimmune attack of insulin producing beta cells in the pancreas by the innate and adaptive immune systems, beta cell death being predominantly T cell-mediated. In addition to T cells, peripheral B cells are important in T1D progression. The thymus of mice and man also contains B cells, and lately they have been linked to central tolerance of T cells. The role of thymic B cells in T1D is undefined. Here, we show there are abnormalities in the thymic B cell compartment before beta cell destruction and T1D manifestation. Using non-obese diabetic (NOD) mice, we document that preceding T1D development, there is significant accumulation of thymic B cells-partly through in situ development- and the putative formation of ectopic germinal centers. In addition, in NOD mice we quantify thymic plasma cells and observe in situ binding of immunoglobulins to undefined antigens on a proportion of medullary thymic epithelial cells (mTECs). By contrast, no ectopic germinal centers or pronounced intrathymic autoantibodies are detectable in animals not genetically predisposed to developing T1D. Binding of autoantibodies to thymic stroma correlates with apoptosis of mTECs, including insulin-expressing cells. By contrast, apoptosis of mTECs was decreased by 50% in B cell-deficient NOD mice suggesting intrathymic autoantibodies may selectively target certain mTECs for destruction. Furthermore, we observe that these thymic B cell-associated events correlated with an increased prevalence of premature thymic emigration of T cells. Together, our data suggest that the thymus may be a principal autoimmune target in T1D and contributes to disease progression.
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Affiliation(s)
- Ana Isabel Pinto
- Centre for Immunology and Infection, Department of Biology, Hull York Medical School, University of York, York, United Kingdom
| | - Jennifer Smith
- Cambridge Institute for Medical Research, University of Cambridge, Addenbrooke's Hospital, Cambridge, United Kingdom
| | - Miriam R Kissack
- Centre for Immunology and Infection, Department of Biology, Hull York Medical School, University of York, York, United Kingdom
| | - Karen G Hogg
- Centre for Immunology and Infection, Department of Biology, Hull York Medical School, University of York, York, United Kingdom
| | - E Allison Green
- Centre for Immunology and Infection, Department of Biology, Hull York Medical School, University of York, York, United Kingdom.,Cambridge Institute for Medical Research, University of Cambridge, Addenbrooke's Hospital, Cambridge, United Kingdom
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29
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Christen U. Animal models of autoimmune hepatitis. Biochim Biophys Acta Mol Basis Dis 2018; 1865:970-981. [PMID: 29857050 DOI: 10.1016/j.bbadis.2018.05.017] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 05/14/2018] [Accepted: 05/22/2018] [Indexed: 02/06/2023]
Abstract
Many animal models for autoimmune hepatitis (AIH) have been described in the past. Most models had to deal with the relative immunosuppressive environment of the liver. Therefore, some models used a combination of several triggering factors often on a susceptible background to generate an aggressive immune response that targets the liver. In addition, in order to be able to track the immune response the models used specific model autoantigens as targets that are either not present or have not been identified as a natural autoantigen in AIH patients. Thereby the feasibility of such models is somewhat questionable. Although many historic approaches included challenges of experimental animals with liver homogenates it was only in the last decade that natural occurring liver autoantigens have been used in animal models. This article reflects on the requirements for breaking liver tolerance and on how an ideal experimental model for AIH would look like. In addition, it discusses historic as well as recent animal models in the context of feasibility of induction, similarity of the clinical outcome to human AIH, and gain of knowledge for possible future therapies.
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Affiliation(s)
- Urs Christen
- Pharmazentrum Frankfurt/ZAFES, Goethe University Hospital, Frankfurt am Main, Germany.
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30
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Mieli-Vergani G, Vergani D, Czaja AJ, Manns MP, Krawitt EL, Vierling JM, Lohse AW, Montano-Loza AJ. Autoimmune hepatitis. Nat Rev Dis Primers 2018; 4:18017. [PMID: 29644994 DOI: 10.1038/nrdp.2018.17] [Citation(s) in RCA: 235] [Impact Index Per Article: 39.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Autoimmune hepatitis (AIH) is a severe liver disease that affects children and adults worldwide. The diagnosis of AIH relies on increased serum transaminase and immunoglobulin G levels, presence of autoantibodies and interface hepatitis on liver histology. AIH arises in genetically predisposed individuals when a trigger, such as exposure to a virus, leads to a T cell-mediated autoimmune response directed against liver autoantigens; this immune response is permitted by inadequate regulatory immune control leading to a loss of tolerance. AIH responds favourably to immunosuppressive treatment, which should be started as soon as the diagnosis is made. Standard regimens include fairly high initial doses of corticosteroids (prednisone or prednisolone), which are tapered gradually as azathioprine is introduced. For those patients who do not respond to standard treatment, second-line drugs should be considered, including mycophenolate mofetil, calcineurin inhibitors, mechanistic target of rapamycin (mTOR) inhibitors and biologic agents, which should be administered only in specialized hepatology centres. Liver transplantation is a life-saving option for those who progress to end-stage liver disease, although AIH can recur or develop de novo after transplantation. In-depth investigation of immune pathways and analysis of changes to the intestinal microbiota should advance our knowledge of the pathogenesis of AIH and lead to novel, tailored and better tolerated therapies.
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Affiliation(s)
- Giorgina Mieli-Vergani
- Paediatric Liver, GI and Nutrition Centre, MowatLabs, King's College Hospital, Denmark Hill, SE5 9RS London, UK
| | - Diego Vergani
- Institute of Liver Studies, MowatLabs, King's College Hospital, Denmark Hill, SE5 9RS London, UK
| | - Albert J Czaja
- Division of Gastroenterology and Hepatology, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Michael P Manns
- Department of Gastroenterology, Hepatology and Endocrinology, Hannover Medical School, Hannover, Germany.,Helmholtz Centre for Infection Research (HZI), Braunschweig, Germany
| | - Edward L Krawitt
- Department of Medicine, University of Vermont, Burlington, VT, USA.,Department of Medicine, Geisel School of Medicine at Dartmouth College, Hanover, NH, USA
| | - John M Vierling
- Division of Abdominal Transplantation and Section of Gastroenterology and Hepatology, Departments of Medicine and Surgery, Baylor College of Medicine, Houston, TX, USA
| | - Ansgar W Lohse
- Department of Medicine, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany
| | - Aldo J Montano-Loza
- Division of Gastroenterology and Liver Unit, University of Alberta, Edmonton, Alberta, Canada
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Abstract
About two decades ago, cloning of the autoimmune regulator (AIRE) gene materialized one of the most important actors on the scene of self-tolerance. Thymic transcription of genes encoding tissue-specific antigens (ts-ags) is activated by AIRE protein and embodies the essence of thymic self-representation. Pathogenic AIRE variants cause the autoimmune polyglandular syndrome type 1, which is a rare and complex disease that is gaining attention in research on autoimmunity. The animal models of disease, although not identically reproducing the human picture, supply fundamental information on mechanisms and extent of AIRE action: thanks to its multidomain structure, AIRE localizes to chromatin enclosing the target genes, binds to histones, and offers an anchorage to multimolecular complexes involved in initiation and post-initiation events of gene transcription. In addition, AIRE enhances mRNA diversity by favoring alternative mRNA splicing. Once synthesized, ts-ags are presented to, and cause deletion of the self-reactive thymocyte clones. However, AIRE function is not restricted to the activation of gene transcription. AIRE would control presentation and transfer of self-antigens for thymic cellular interplay: such mechanism is aimed at increasing the likelihood of engagement of the thymocytes that carry the corresponding T-cell receptors. Another fundamental role of AIRE in promoting self-tolerance is related to the development of thymocyte anergy, as thymic self-representation shapes at the same time the repertoire of regulatory T cells. Finally, AIRE seems to replicate its action in the secondary lymphoid organs, albeit the cell lineage detaining such property has not been fully characterized. Delineation of AIRE functions adds interesting data to the knowledge of the mechanisms of self-tolerance and introduces exciting perspectives of therapeutic interventions against the related diseases.
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Affiliation(s)
- Roberto Perniola
- Department of Pediatrics, Neonatal Intensive Care, Vito Fazzi Regional Hospital, Lecce, Italy
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32
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Lalani AI, Zhu S, Gokhale S, Jin J, Xie P. TRAF molecules in inflammation and inflammatory diseases. ACTA ACUST UNITED AC 2017. [PMID: 29527458 DOI: 10.1007/s40495-017-0117-y] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Purpose of Review This review presents an overview of the current knowledge of TRAF molecules in inflammation with an emphasis on available human evidence and direct in vivo evidence of mouse models that demonstrate the contribution of TRAF molecules in the pathogenesis of inflammatory diseases. Recent Findings The tumor necrosis factor receptor (TNF-R)-associated factor (TRAF) family of cytoplasmic proteins was initially identified as signaling adaptors that bind directly to the intracellular domains of receptors of the TNF-R superfamily. It is now appreciated that TRAF molecules are widely employed in signaling by a variety of adaptive and innate immune receptors as well as cytokine receptors. TRAF-dependent signaling pathways typically lead to the activation of nuclear factor-κBs (NF-κBs), mitogen-activated protein kinases (MAPKs), or interferon-regulatory factors (IRFs). Most of these signaling pathways have been linked to inflammation, and therefore TRAF molecules were expected to regulate inflammation and inflammatory responses since their discovery in 1990s. However, direct in vivo evidence of TRAFs in inflammation and especially in inflammatory diseases had been lacking for many years, partly due to the difficulty imposed by early lethality of TRAF2-/-, TRAF3-/-, and TRAF6-/- mice. With the creation of conditional knockout and lineage-specific transgenic mice of different TRAF molecules, our understanding about TRAFs in inflammation and inflammatory responses has rapidly advanced during the past decade. Summary Increasing evidence indicates that TRAF molecules are versatile and indispensable regulators of inflammation and inflammatory responses and that aberrant expression or function of TRAFs contributes to the pathogenesis of inflammatory diseases.
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Affiliation(s)
- Almin I Lalani
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, New Jersey 08854
- Graduate Program in Cellular and Molecular Pharmacology, Rutgers University, Piscataway, New Jersey 08854
| | - Sining Zhu
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, New Jersey 08854
- Graduate Program in Cellular and Molecular Pharmacology, Rutgers University, Piscataway, New Jersey 08854
| | - Samantha Gokhale
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, New Jersey 08854
- Graduate Program in Cellular and Molecular Pharmacology, Rutgers University, Piscataway, New Jersey 08854
| | - Juan Jin
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, New Jersey 08854
- Department of Pharmacology, Anhui Medical University, Meishan Road 81st, Shushan District, Hefei, Anhui province, China
| | - Ping Xie
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, New Jersey 08854
- Member, Rutgers Cancer Institute of New Jersey
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Engelmann R, Biemelt A, Johl A, Kuthning D, Müller-Hilke B. Reduced Numbers of Mature Medullary Thymic Epithelial Cells in SKG Mice. Scand J Immunol 2017; 87:28-35. [PMID: 29105157 DOI: 10.1111/sji.12626] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Accepted: 10/25/2017] [Indexed: 11/27/2022]
Abstract
Attenuated T cell receptor (TCR) signalling contributes to the susceptibility for autoimmunity as shown via mutants of PTPN22 and Zap70 genes. We here set out to investigate the effect of an attenuated TCR signal on the composition of the thymic epithelial cell (TEC) compartment. To that extent, we combined flow cytometry and histology and compared the TEC subpopulations of Zap70 wild type with SKG mutant mice. We found an increased cortical TEC compartment in SKG thymi at the expense of reduced numbers of mature medullary TECs and a 4.8-fold reduced medulla area. We also found reduced proportions of CD69+ -activated thymocytes among double-negative, double-positive and CD4- CD8+ single-positive stages, reduced absolute numbers of single-positive thymocytes, diminished expression of Lta and Ltb by CD4- CD8+ single-positive thymocytes and a diminished expression of Ccl19, a target gene of the lymphotoxin-b-receptor. While the reduced thymocyte numbers together with the attenuated TCR signal explain the diminished expression of lymphotoxins, the latter is required for an AIRE-independent expression of tissue-restricted antigens as well as attracting positively selected thymocytes to the medulla. Our results describe altered TEC compartments in SKG mice that are likely to support the development of autoimmunity.
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Affiliation(s)
- R Engelmann
- AG Clinical Immunology, Institute of Immunology, Rostock University Medical Center, Rostock, Germany
| | - A Biemelt
- AG Clinical Immunology, Institute of Immunology, Rostock University Medical Center, Rostock, Germany
| | - A Johl
- AG Clinical Immunology, Institute of Immunology, Rostock University Medical Center, Rostock, Germany
| | - D Kuthning
- AG Clinical Immunology, Institute of Immunology, Rostock University Medical Center, Rostock, Germany
| | - B Müller-Hilke
- AG Clinical Immunology, Institute of Immunology, Rostock University Medical Center, Rostock, Germany
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Shen H, Sheng L, Xiong Y, Kim YH, Jiang L, Chen Z, Liu Y, Pyaram K, Chang CH, Rui L. Thymic NF-κB-inducing kinase regulates CD4 + T cell-elicited liver injury and fibrosis in mice. J Hepatol 2017; 67:100-109. [PMID: 28267623 PMCID: PMC5476485 DOI: 10.1016/j.jhep.2017.02.025] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Revised: 02/16/2017] [Accepted: 02/21/2017] [Indexed: 12/29/2022]
Abstract
BACKGROUND & AIMS The liver is an immunologically-privileged organ. Breakdown of liver immune privilege has been reported in chronic liver disease; however, the role of adaptive immunity in liver injury is poorly defined. Nuclear factor-κB-inducing kinase (NIK) is known to regulate immune tissue development, but its role in maintaining liver homeostasis remains unknown. This study aimed to assess the role of NIK, particularly thymic NIK, in regulating liver adaptive immunity. METHODS NIK was deleted systemically or conditionally using the Cre/loxp system. Cluster of differentiation [CD]4+ or CD8+ T cells were depleted using anti-CD4 or anti-CD8 antibody. Donor bone marrows or thymi were transferred into recipient mice. Immune cells were assessed by immunohistochemistry and flow cytometry. RESULTS Global, but not liver-specific or hematopoietic lineage cell-specific, deletion of NIK induced fatal liver injury, inflammation, and fibrosis. Likewise, adoptive transfer of NIK-null, but not wild-type, thymi into immune-deficient mice induced liver inflammation, injury, and fibrosis in recipients. Liver inflammation was characterized by a massive expansion of T cells, particularly the CD4+ T cell subpopulation. Depletion of CD4+, but not CD8+, T cells fully protected against liver injury, inflammation, and fibrosis in NIK-null mice. NIK deficiency also resulted in inflammation in the lung, kidney, and pancreas, but to a lesser degree relative to the liver. CONCLUSIONS Thymic NIK suppresses development of autoreactive T cells against liver antigens, and NIK deficiency in the thymus results in CD4+ T cell-orchestrated autoimmune hepatitis and liver fibrosis. Thus, thymic NIK is essential for the maintenance of liver immune privilege and liver homeostasis. LAY SUMMARY We found that global or thymus-specific ablation of the NIK gene results in fatal autoimmune liver disease in mice. NIK-deficient mice develop liver inflammation, injury, and fibrosis. Our findings indicate that thymic NIK is essential for the maintenance of liver integrity and homeostasis.
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Affiliation(s)
- Hong Shen
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Liang Sheng
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Yi Xiong
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Yeung-Hyen Kim
- Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Lin Jiang
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Zheng Chen
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Yong Liu
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, the Institute for Advanced Studies, Wuhan University, Wuhan 430072, China
| | - Kalyani Pyaram
- Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Cheong-Hee Chang
- Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Liangyou Rui
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109, USA.
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35
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Riemann M, Andreas N, Fedoseeva M, Meier E, Weih D, Freytag H, Schmidt-Ullrich R, Klein U, Wang ZQ, Weih F. Central immune tolerance depends on crosstalk between the classical and alternative NF-κB pathways in medullary thymic epithelial cells. J Autoimmun 2017; 81:56-67. [DOI: 10.1016/j.jaut.2017.03.007] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Revised: 03/13/2017] [Accepted: 03/13/2017] [Indexed: 10/19/2022]
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36
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Gil-Farina I, Di Scala M, Salido E, López-Franco E, Rodríguez-García E, Blasi M, Merino J, Aldabe R, Prieto J, Gonzalez-Aseguinolaza G. Transient Expression of Transgenic IL-12 in Mouse Liver Triggers Unremitting Inflammation Mimicking Human Autoimmune Hepatitis. THE JOURNAL OF IMMUNOLOGY 2016; 197:2145-2156. [DOI: 10.4049/jimmunol.1600228] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/30/2023]
Abstract
Abstract
The etiopathogenesis of autoimmune hepatitis (AIH) remains poorly understood. In this study, we sought to develop an animal model of human AIH to gain insight into the immunological mechanisms driving this condition. C57BL/6 mice were i.v. injected with adeno-associated viral vectors encoding murine IL-12 or luciferase under the control of a liver-specific promoter. Organ histology, response to immunosuppressive therapy, and biochemical and immunological parameters, including Ag-specific humoral and cellular response, were analyzed. Mechanistic studies were carried out using genetically modified mice and depletion of lymphocyte subpopulations. Adeno-associated virus IL-12–treated mice developed histological, biochemical, and immunological changes resembling type 1 AIH, including marked and persistent liver mononuclear cell infiltration, hepatic fibrosis, hypergammaglobulinemia, anti-nuclear and anti–smooth muscle actin Abs, and disease remission with immunosuppressive drugs. Interestingly, transgenic IL-12 was short-lived, but endogenous IL-12 expression was induced, and both IL-12 and IFN-γ remained elevated during the entire study period. IFN-γ was identified as an essential mediator of liver damage, and CD4 and CD8 T cells but not NK, NKT, or B cells were essential executors of hepatic injury. Furthermore, both MHC class I and MHC class II expression was upregulated at the hepatocellular membrane, and induction of autoreactive liver-specific T cells was detected. Remarkably, although immunoregulatory mechanisms were activated, they only partially mitigated liver damage. Thus, low and transient expression of transgenic IL-12 in hepatocytes causes loss of tolerance to hepatocellular Ags, leading to chronic hepatitis resembling human AIH type 1. This model provides a practical tool to explore AIH pathogenesis and novel therapies.
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Affiliation(s)
- Irene Gil-Farina
- *Gene Therapy and Regulation of Gene Expression Program, Center for Applied Medical Research, Health Research Institute of Navarra, 31008 Pamplona, Spain
| | - Marianna Di Scala
- *Gene Therapy and Regulation of Gene Expression Program, Center for Applied Medical Research, Health Research Institute of Navarra, 31008 Pamplona, Spain
| | - Eduardo Salido
- †Unidad de Investigación Mixta Hospital Universitario de Canarias–Universidad de La Laguna, Facultad de Medicina, Universidad de La Laguna, 38071 Santa Cruz de Tenerife, Spain; and
| | - Esperanza López-Franco
- *Gene Therapy and Regulation of Gene Expression Program, Center for Applied Medical Research, Health Research Institute of Navarra, 31008 Pamplona, Spain
| | - Estefania Rodríguez-García
- *Gene Therapy and Regulation of Gene Expression Program, Center for Applied Medical Research, Health Research Institute of Navarra, 31008 Pamplona, Spain
| | - Mercedes Blasi
- *Gene Therapy and Regulation of Gene Expression Program, Center for Applied Medical Research, Health Research Institute of Navarra, 31008 Pamplona, Spain
| | - Juana Merino
- ‡University Clinic of Navarra, University of Navarra, 31008 Pamplona, Spain
| | - Rafael Aldabe
- *Gene Therapy and Regulation of Gene Expression Program, Center for Applied Medical Research, Health Research Institute of Navarra, 31008 Pamplona, Spain
| | - Jesús Prieto
- *Gene Therapy and Regulation of Gene Expression Program, Center for Applied Medical Research, Health Research Institute of Navarra, 31008 Pamplona, Spain
- ‡University Clinic of Navarra, University of Navarra, 31008 Pamplona, Spain
| | - Gloria Gonzalez-Aseguinolaza
- *Gene Therapy and Regulation of Gene Expression Program, Center for Applied Medical Research, Health Research Institute of Navarra, 31008 Pamplona, Spain
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Herbin O, Bonito AJ, Jeong S, Weinstein EG, Rahman AH, Xiong H, Merad M, Alexandropoulos K. Medullary thymic epithelial cells and CD8α + dendritic cells coordinately regulate central tolerance but CD8α + cells are dispensable for thymic regulatory T cell production. J Autoimmun 2016; 75:141-149. [PMID: 27543048 DOI: 10.1016/j.jaut.2016.08.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Revised: 07/29/2016] [Accepted: 08/03/2016] [Indexed: 10/21/2022]
Abstract
In the thymus, antigen presenting cells (APCs) namely, medullary thymic epithelial cells (mTECs) and thymic dendritic cells (tDCs) regulate T cell tolerance through elimination of autoreactive T cells and production of thymic T regulatory (tTreg) cells. How the different APCs in the thymus share the burden of tolerazing the emerging T cell repertoire remains unclear. For example, while mutations that inhibit mTEC development or function associate with peripheral autoimmunity, the role of tDCs in organ-specific autoimmunity and tTreg cell production remains controversial. In this report we used mice depleted of mTECs and/or CD8α+ DCs, to examine the contributions of these cell populations in thymic tolerance. We found that while mice depleted of CD8α+ DCs or mTECs were normal or developed liver inflammation respectively, combined depletion of mTECs and CD8α+ DCs resulted in overt peripheral autoimmunity. The autoimmune manifestations in mice depleted of both mTECs and CD8α+ cDCs associated with increased percentages of CD4+ and CD8+ T cells in the thymus. In contrast, while mTEC depletion resulted in reduced percentages of tTreg cells, no additional effect was observed when CD8α+ DCs were also depleted. These results reveal that: 1) mTECs and CD8α+ DCs cooperatively safeguard against peripheral autoimmunity through thymic T cell deletion; 2) CD8α+ DCs are dispensable for tTreg cell production, whereas mTECs play a non-redundant role in this process; 3) mTECs and CD8α+ DCs make unique contributions to tolerance induction that cannot be compensated for by other thymic APCs such as migratory SIRPα+ or plasmacytoid DCs.
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Affiliation(s)
- Olivier Herbin
- Department of Medicine/Clinical Immunology, The Immunology Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Anthony J Bonito
- Department of Medicine/Clinical Immunology, The Immunology Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Seihwan Jeong
- Department of Medicine/Clinical Immunology, The Immunology Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Erica G Weinstein
- Department of Medicine/Clinical Immunology, The Immunology Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Adeeb H Rahman
- Department of Medicine/Clinical Immunology, The Immunology Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA; The Tisch Cancer Institute/Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Huabao Xiong
- Department of Medicine/Clinical Immunology, The Immunology Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Miriam Merad
- Department of Medicine/Clinical Immunology, The Immunology Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA; The Tisch Cancer Institute/Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Konstantina Alexandropoulos
- Department of Medicine/Clinical Immunology, The Immunology Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
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Walsh MC, Lee J, Choi Y. Tumor necrosis factor receptor- associated factor 6 (TRAF6) regulation of development, function, and homeostasis of the immune system. Immunol Rev 2016; 266:72-92. [PMID: 26085208 DOI: 10.1111/imr.12302] [Citation(s) in RCA: 292] [Impact Index Per Article: 36.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Tumor necrosis factor receptor (TNFR)-associated factor 6 (TRAF6) is an adapter protein that mediates a wide array of protein-protein interactions via its TRAF domain and a RING finger domain that possesses non-conventional E3 ubiquitin ligase activity. First identified nearly two decades ago as a mediator of interleukin-1 receptor (IL-1R)-mediated activation of NFκB, TRAF6 has since been identified as an actor downstream of multiple receptor families with immunoregulatory functions, including members of the TNFR superfamily, the Toll-like receptor (TLR) family, tumor growth factor-β receptors (TGFβR), and T-cell receptor (TCR). In addition to NFκB, TRAF6 may also direct activation of mitogen-activated protein kinase (MAPK), phosphoinositide 3-kinase (PI3K), and interferon regulatory factor pathways. In the context of the immune system, TRAF6-mediated signals have proven critical for the development, homeostasis, and/or activation of B cells, T cells, and myeloid cells, including macrophages, dendritic cells, and osteoclasts, as well as for organogenesis of thymic and secondary lymphoid tissues. In multiple cellular contexts, TRAF6 function is essential not only for proper activation of the immune system but also for maintaining immune tolerance, and more recent work has begun to identify mechanisms of contextual specificity for TRAF6, involving both regulatory protein interactions, and messenger RNA regulation by microRNAs.
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Affiliation(s)
- Matthew C Walsh
- Institute for Immunology and Department of Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - JangEun Lee
- Institute for Immunology and Department of Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Yongwon Choi
- Institute for Immunology and Department of Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
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Lucas B, McCarthy NI, Baik S, Cosway E, James KD, Parnell SM, White AJ, Jenkinson WE, Anderson G. Control of the thymic medulla and its influence on αβT-cell development. Immunol Rev 2016; 271:23-37. [PMID: 27088905 PMCID: PMC4982089 DOI: 10.1111/imr.12406] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The thymus is a primary lymphoid tissue that supports the generation of αβT cells. In this review, we describe the processes that give rise to the thymus medulla, a site that nurtures self-tolerant T-cell generation following positive selection events that take place in the cortex. To summarize the developmental pathways that generate medullary thymic epithelial cells (mTEC) from their immature progenitors, we describe work on both the initial emergence of the medulla during embryogenesis, and the maintenance of the medulla during postnatal stages. We also investigate the varying roles that receptors belonging to the tumor necrosis factor receptor superfamily have on thymus medulla development and formation, and highlight the impact that T-cell development has on thymus medulla formation. Finally, we examine the evidence that the thymic medulla plays an important role during the intrathymic generation of distinct αβT-cell subtypes. Collectively, these studies provide new insight into the development and functional importance of medullary microenvironments during self-tolerant T-cell production in the thymus.
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Affiliation(s)
- Beth Lucas
- MRC Centre for Immune RegulationInstitute for Immunology and ImmunotherapyMedical SchoolUniversity of BirminghamBirminghamUK
| | - Nicholas I. McCarthy
- MRC Centre for Immune RegulationInstitute for Immunology and ImmunotherapyMedical SchoolUniversity of BirminghamBirminghamUK
| | - Song Baik
- MRC Centre for Immune RegulationInstitute for Immunology and ImmunotherapyMedical SchoolUniversity of BirminghamBirminghamUK
| | - Emilie Cosway
- MRC Centre for Immune RegulationInstitute for Immunology and ImmunotherapyMedical SchoolUniversity of BirminghamBirminghamUK
| | - Kieran D. James
- MRC Centre for Immune RegulationInstitute for Immunology and ImmunotherapyMedical SchoolUniversity of BirminghamBirminghamUK
| | - Sonia M. Parnell
- MRC Centre for Immune RegulationInstitute for Immunology and ImmunotherapyMedical SchoolUniversity of BirminghamBirminghamUK
| | - Andrea J. White
- MRC Centre for Immune RegulationInstitute for Immunology and ImmunotherapyMedical SchoolUniversity of BirminghamBirminghamUK
| | - William E. Jenkinson
- MRC Centre for Immune RegulationInstitute for Immunology and ImmunotherapyMedical SchoolUniversity of BirminghamBirminghamUK
| | - Graham Anderson
- MRC Centre for Immune RegulationInstitute for Immunology and ImmunotherapyMedical SchoolUniversity of BirminghamBirminghamUK
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Webb G, Chen YY, Li KK, Neil D, Oo YH, Richter A, Bigley V, Collin M, Adams DH, Hirschfield GM. Single-gene association between GATA-2 and autoimmune hepatitis: A novel genetic insight highlighting immunologic pathways to disease. J Hepatol 2016; 64:1190-1193. [PMID: 26812071 PMCID: PMC4824751 DOI: 10.1016/j.jhep.2016.01.017] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Revised: 01/15/2016] [Accepted: 01/19/2016] [Indexed: 01/06/2023]
Abstract
Background & Aims Autoimmune hepatitis (AIH), an immune-mediated liver disease, originates as a consequence of interacting genetic and environmental risk factors. Treatment remains non-specific and prone to side effects. Deficiencies in regulatory T cell (Treg) function are hypothesized to contribute to the pathogenesis of AIH. Methods We describe an adult patient who presented with AIH in the context of monocytopenia. The patient was characterized by GATA2 gene sequencing, flow cytometry of peripheral blood for leucocyte subsets, ELISA for serum Flt-3 ligand, and immunohistochemistry of liver biopsy tissue. Results Sequencing confirmed a GATA2 mutation. Peripheral Treg were absent in the context of a preserved total T cell count. Immunostaining for the Treg transcription factor FOXP3 was reduced in liver tissue as compared to a control AIH specimen. There were marked deficiencies in multiple antigen-presenting cell subsets and Flt-3 ligand was elevated. These findings are consistent with previous reports of GATA2 dysfunction. Conclusions The association of a GATA2 mutation with AIH is previously unrecognized. GATA2 encodes a hematopoietic cell transcription factor, and mutations may manifest as monocytopenia, dendritic and B cell deficiencies, myelodysplasia, and immunodeficiency. Tregs may be depleted as in this case. Our findings provide support for the role of Tregs in AIH, complement reports of other deficiencies in T cell regulation causing AIH-like syndromes, and support the rationale of attempting to modulate the Treg axis for the therapeutic benefit of AIH patients.
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Affiliation(s)
- Gwilym Webb
- Centre for Liver Research, University of Birmingham and NIHR Birmingham Liver Biomedical Research Unit, Birmingham, UK
| | - Yung-Yi Chen
- Centre for Liver Research, University of Birmingham and NIHR Birmingham Liver Biomedical Research Unit, Birmingham, UK
| | - Ka-Kit Li
- Centre for Liver Research, University of Birmingham and NIHR Birmingham Liver Biomedical Research Unit, Birmingham, UK
| | - Desley Neil
- Department of Pathology, Queen Elizabeth Hospital, Birmingham, UK
| | - Ye Htun Oo
- Centre for Liver Research, University of Birmingham and NIHR Birmingham Liver Biomedical Research Unit, Birmingham, UK
| | - Alex Richter
- Department of Immunology, Queen Elizabeth Hospital, Birmingham, UK
| | - Venetia Bigley
- Institute of Cellular Medicine, Newcastle University, Newcastle, UK
| | - Matthew Collin
- Institute of Cellular Medicine, Newcastle University, Newcastle, UK
| | - David H Adams
- Centre for Liver Research, University of Birmingham and NIHR Birmingham Liver Biomedical Research Unit, Birmingham, UK
| | - Gideon M Hirschfield
- Centre for Liver Research, University of Birmingham and NIHR Birmingham Liver Biomedical Research Unit, Birmingham, UK.
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Goldfarb Y, Kadouri N, Levi B, Sela A, Herzig Y, Cohen RN, Hollenberg AN, Abramson J. HDAC3 Is a Master Regulator of mTEC Development. Cell Rep 2016; 15:651-665. [PMID: 27068467 DOI: 10.1016/j.celrep.2016.03.048] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Revised: 02/03/2016] [Accepted: 03/11/2016] [Indexed: 01/03/2023] Open
Abstract
The thymus provides a unique microenvironment enabling development and selection of T lymphocytes. Medullary thymic epithelial cells (mTECs) play a pivotal role in this process by facilitating negative selection of self-reactive thymocytes and the generation of Foxp3(+) regulatory T cells. Although studies have highlighted the non-canonical nuclear factor κB (NF-κB) pathway as the key regulator of mTEC development, comprehensive understanding of the molecular pathways regulating this process still remains incomplete. Here, we demonstrate that the development of functionally competent mTECs is regulated by the histone deacetylase 3 (Hdac3). Although histone deacetylases are global transcriptional regulators, this effect is highly specific only to Hdac3, as neither Hdac1 nor Hdac2 inactivation caused mTEC ablation. Interestingly, Hdac3 induces an mTEC-specific transcriptional program independently of the previously recognized RANK-NFκB signaling pathway. Thus, our findings uncover yet another layer of complexity of TEC lineage divergence and highlight Hdac3 as a major and specific molecular switch crucial for mTEC differentiation.
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Affiliation(s)
- Yael Goldfarb
- Department of Immunology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Noam Kadouri
- Department of Immunology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Ben Levi
- Department of Immunology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Asaf Sela
- Department of Immunology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Yonatan Herzig
- Department of Immunology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Ronald N Cohen
- University of Chicago Medical Centre, Chicago, IL 60637, USA
| | - Anthony N Hollenberg
- Division of Endocrinology, Beth Israel Deaconess Medical Centre, Boston, MA 02215, USA
| | - Jakub Abramson
- Department of Immunology, Weizmann Institute of Science, Rehovot 76100, Israel.
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Abstract
Ubiquitination has emerged as a crucial mechanism that regulates signal transduction in diverse biological processes, including different aspects of immune functions. Ubiquitination regulates pattern-recognition receptor signaling that mediates both innate immune responses and dendritic cell maturation required for initiation of adaptive immune responses. Ubiquitination also regulates the development, activation, and differentiation of T cells, thereby maintaining efficient adaptive immune responses to pathogens and immunological tolerance to self-tissues. Like phosphorylation, ubiquitination is a reversible reaction tightly controlled by the opposing actions of ubiquitin ligases and deubiquitinases. Deregulated ubiquitination events are associated with immunological disorders, including autoimmune and inflammatory diseases.
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Affiliation(s)
- Hongbo Hu
- Department of Rheumatology and Immunology, State Key Laboratory of Biotherapy & Collaborative Innovation Center for Biotherapy, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Shao-Cong Sun
- Department of Immunology, The University of Texas MD Anderson Cancer Center, 7455 Fannin Street, Unit 902, Houston, TX 77030, USA.,The University of Texas Graduate School of Biomedical Sciences, Houston, TX 77030, USA
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Lin J, Yang L, Silva HM, Trzeciak A, Choi Y, Schwab SR, Dustin ML, Lafaille JJ. Increased generation of Foxp3(+) regulatory T cells by manipulating antigen presentation in the thymus. Nat Commun 2016; 7:10562. [PMID: 26923114 PMCID: PMC4773449 DOI: 10.1038/ncomms10562] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2015] [Accepted: 12/28/2015] [Indexed: 12/22/2022] Open
Abstract
Regulatory T-cell (Treg) selection in the thymus is essential to prevent autoimmune diseases. Although important rules for Treg selection have been established, there is controversy regarding the degree of self-reactivity displayed by T-cell receptors expressed by Treg cells. In this study we have developed a model of autoimmune skin inflammation, to determine key parameters in the generation of skin-reactive Treg cells in the thymus (tTreg). tTreg development is predominantly AIRE dependent, with an AIRE-independent component. Without the knowledge of antigen recognized by skin-reactive Treg cells, we are able to enhance skin-specific tTreg cell generation using three approaches. First, we increase medullary thymic epithelial cells by using mice lacking osteoprotegerin or by adding TRANCE (RANKL, Tnfsf11). Second, we inject intrathymically peripheral dendritic cells from skin-draining sites. Finally, we inject skin tissue lysates intrathymically. These findings have implications for enhancing the generation of organ-specific Treg cells in autoimmune diseases.
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Affiliation(s)
- Jiqiang Lin
- Molecular Pathogenesis Program, Kimmel Center for Biology and Medicine at the Skirball Institute, New York University School of Medicine, 540 First Avenue, New York, New York 10016, USA
- The Sackler Institute of Graduate Biomedical Sciences, New York University School of Medicine, New York, New York 10016, USA
| | - Lu Yang
- Molecular Pathogenesis Program, Kimmel Center for Biology and Medicine at the Skirball Institute, New York University School of Medicine, 540 First Avenue, New York, New York 10016, USA
- The Sackler Institute of Graduate Biomedical Sciences, New York University School of Medicine, New York, New York 10016, USA
| | - Hernandez Moura Silva
- Molecular Pathogenesis Program, Kimmel Center for Biology and Medicine at the Skirball Institute, New York University School of Medicine, 540 First Avenue, New York, New York 10016, USA
| | - Alissa Trzeciak
- Molecular Pathogenesis Program, Kimmel Center for Biology and Medicine at the Skirball Institute, New York University School of Medicine, 540 First Avenue, New York, New York 10016, USA
| | - Yongwon Choi
- Department of Pathology and Laboratory Medicine, Institute for Immunology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104, USA
| | - Susan R. Schwab
- Molecular Pathogenesis Program, Kimmel Center for Biology and Medicine at the Skirball Institute, New York University School of Medicine, 540 First Avenue, New York, New York 10016, USA
- Department of Pathology, New York University School of Medicine, New York, New York 10016, USA
| | - Michael L. Dustin
- Molecular Pathogenesis Program, Kimmel Center for Biology and Medicine at the Skirball Institute, New York University School of Medicine, 540 First Avenue, New York, New York 10016, USA
- Department of Pathology, New York University School of Medicine, New York, New York 10016, USA
- Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, Kennedy Institute of Rheumatology, University of Oxford, Oxford OX3 7FY, UK
| | - Juan J. Lafaille
- Molecular Pathogenesis Program, Kimmel Center for Biology and Medicine at the Skirball Institute, New York University School of Medicine, 540 First Avenue, New York, New York 10016, USA
- Department of Pathology, New York University School of Medicine, New York, New York 10016, USA
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Treg Cell Differentiation: From Thymus to Peripheral Tissue. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2015; 136:175-205. [PMID: 26615097 DOI: 10.1016/bs.pmbts.2015.07.014] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Regulatory T cells (Tregs) are crucial mediators of self-tolerance in the periphery. They differentiate in the thymus, where interactions with thymus-resident antigen-presenting cells, an instructive cytokine milieu, and stimulation of the T cell receptor lead to the selection into the Treg lineage and the induction of Foxp3 gene expression. Once mature, Treg cells leave the thymus and migrate into either the secondary lymphoid tissues, e.g., lymph nodes and spleen, or peripheral nonlymphoid tissues. There is growing evidence that Treg cells go beyond the classical modulation of immune responses and also play important functional roles in nonlymphoid peripheral tissues. In this review, we summarize recent findings about the thymic Treg lineage differentiation as well as the further specialization of Treg cells in the secondary lymphoid and in the peripheral nonlymphoid organs.
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Hu Z, Lancaster JN, Ehrlich LIR. The Contribution of Chemokines and Migration to the Induction of Central Tolerance in the Thymus. Front Immunol 2015; 6:398. [PMID: 26300884 PMCID: PMC4528182 DOI: 10.3389/fimmu.2015.00398] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Accepted: 07/20/2015] [Indexed: 02/01/2023] Open
Abstract
As T cells develop, they migrate throughout the thymus where they undergo essential bi-directional signaling with stromal cells in distinct thymic microenvironments. Immature thymocyte progenitors are located in the thymic cortex. Following T cell receptor expression and positive selection, thymocytes undergo a dramatic transition: they become rapidly motile and relocate to the thymic medulla. Antigen-presenting cells (APCs) within the cortex and medulla display peptides derived from a wide array of self-proteins, which promote thymocyte self-tolerance. If a thymocyte is auto-reactive against such antigens, it undergoes either negative selection, via apoptosis, or differentiation into the regulatory T cell lineage. This induction of central tolerance is critical for prevention of autoimmunity. Chemokines and adhesion molecules play an essential role in tolerance induction, as they promote migration of developing thymocytes through the different thymic microenvironments and enhance interactions with APCs displaying self-antigens. Herein, we review the contribution of chemokines and other regulators of thymocyte localization and motility to T cell development, with a focus on their contribution to the induction of central tolerance.
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Affiliation(s)
- Zicheng Hu
- Ehrlich Laboratory, Department of Molecular Biosciences, Institute for Cellular and Molecular Biology, The University of Texas at Austin , Austin, TX , USA
| | - Jessica Naomi Lancaster
- Ehrlich Laboratory, Department of Molecular Biosciences, Institute for Cellular and Molecular Biology, The University of Texas at Austin , Austin, TX , USA
| | - Lauren I R Ehrlich
- Ehrlich Laboratory, Department of Molecular Biosciences, Institute for Cellular and Molecular Biology, The University of Texas at Austin , Austin, TX , USA
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Corrigan M, Hirschfield GM, Oo YH, Adams DH. Autoimmune hepatitis: an approach to disease understanding and management. Br Med Bull 2015; 114:181-91. [PMID: 25995334 DOI: 10.1093/bmb/ldv021] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/15/2015] [Indexed: 12/17/2022]
Abstract
INTRODUCTION Autoimmune hepatitis is a chronic immune-mediated liver injury, frequently associated with progression to end-stage liver disease if untreated. Patients commonly present with hepatitis, positive immune serology, elevated immunoglobulins and compatible liver histology, in the absence of an alternative aetiology. SOURCES OF DATA Data for this review were obtained using PubMed. AREAS OF AGREEMENT Disease usually responds to steroids and azathioprine, and appears to be a manifestation of autoimmune predisposition triggered in genetically susceptible individuals exposed to likely environmental challenges. We provide an up-to-date approach to disease understanding and management along with the clinical approach to diagnosis and current treatment suggestions. AREAS OF CONTROVERSY Controversies such as second line therapies and novel markers of disease activity are introduced. GROWING POINTS Increased understanding of the immunoregulatory mechanisms behind autoimmune hepatitis has led to opportunities for new therapies. These are developed including a discussion of timely research studies relevant to future therapies for patients.
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Affiliation(s)
- Margaret Corrigan
- NIHR Biomedical Research Unit and Centre for Liver Research, University of Birmingham, Birmingham, UK
| | - Gideon M Hirschfield
- NIHR Biomedical Research Unit and Centre for Liver Research, University of Birmingham, Birmingham, UK
| | - Ye H Oo
- NIHR Biomedical Research Unit and Centre for Liver Research, University of Birmingham, Birmingham, UK
| | - David H Adams
- NIHR Biomedical Research Unit and Centre for Liver Research, University of Birmingham, Birmingham, UK
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Alexandropoulos K, Bonito AJ, Weinstein EG, Herbin O. Medullary thymic epithelial cells and central tolerance in autoimmune hepatitis development: novel perspective from a new mouse model. Int J Mol Sci 2015; 16:1980-2000. [PMID: 25603179 PMCID: PMC4307344 DOI: 10.3390/ijms16011980] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Accepted: 01/07/2015] [Indexed: 02/07/2023] Open
Abstract
Autoimmune hepatitis (AIH) is an immune-mediated disorder that affects the liver parenchyma. Diagnosis usually occurs at the later stages of the disease, complicating efforts towards understanding the causes of disease development. While animal models are useful for studying the etiology of autoimmune disorders, most of the existing animal models of AIH do not recapitulate the chronic course of the human condition. In addition, approaches to mimic AIH-associated liver inflammation have instead led to liver tolerance, consistent with the high tolerogenic capacity of the liver. Recently, we described a new mouse model that exhibited spontaneous and chronic liver inflammation that recapitulated the known histopathological and immunological parameters of AIH. The approach involved liver-extrinsic genetic engineering that interfered with the induction of T-cell tolerance in the thymus, the very process thought to inhibit AIH induction by liver-specific expression of exogenous antigens. The mutation led to depletion of specialized thymic epithelial cells that present self-antigens and eliminate autoreactive T-cells before they exit the thymus. Based on our findings, which are summarized below, we believe that this mouse model represents a relevant experimental tool towards elucidating the cellular and molecular aspects of AIH development and developing novel therapeutic strategies for treating this disease.
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Affiliation(s)
- Konstantina Alexandropoulos
- Department of Medicine and Clinical Immunology, the Mount Sinai School of Medicine, One Gustave L. Levy Place, Box 1089, New York, NY 10029, USA.
| | - Anthony J Bonito
- Department of Medicine and Clinical Immunology, the Mount Sinai School of Medicine, One Gustave L. Levy Place, Box 1089, New York, NY 10029, USA.
| | - Erica G Weinstein
- Department of Medicine and Clinical Immunology, the Mount Sinai School of Medicine, One Gustave L. Levy Place, Box 1089, New York, NY 10029, USA
| | - Olivier Herbin
- Department of Medicine and Clinical Immunology, the Mount Sinai School of Medicine, One Gustave L. Levy Place, Box 1089, New York, NY 10029, USA.
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Human thymus medullary epithelial cells promote regulatory T-cell generation by stimulating interleukin-2 production via ICOS ligand. Cell Death Dis 2014; 5:e1420. [PMID: 25210803 PMCID: PMC4540205 DOI: 10.1038/cddis.2014.377] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Revised: 07/13/2014] [Accepted: 07/14/2014] [Indexed: 01/04/2023]
Abstract
Natural thymic T regulatory (tTreg) cells maintain tolerance to self-antigen. These cells are generated in the thymus, but how this generation occurs is still controversial. Furthermore, the contribution of thymus epithelial cells to this process is still unclear, especially in humans. Using an exceptional panel of human thymic samples, we demonstrated that medullary thymus epithelial cells (mTECs) promote the generation of tTreg cells and favor their function. These effects were mediated through soluble factors and were mTEC specific since other cell types had no such effect. By evaluating the effects of mTECs on the absolute number of Treg cells and their state of proliferation or cell death, we conclude that mTECs promote the proliferation of newly generated CD25+ cells from CD4+CD25- cells and protect Treg cells from cell death. This observation implicates Bcl-2 and mitochondrial membrane potential changes, indicating that the intrinsic cell death pathway is involved in Treg protection by mTECs. Interestingly, when the mTECs were cultured directly with purified Treg cells, they were able to promote their phenotype but not their expansion, suggesting that CD4+CD25- cells have a role in the expansion process. To explore the mechanisms involved, several neutralizing antibodies were tested. The effects of mTECs on Treg cells were essentially due to interleukin (IL)-2 overproduction by thymus CD4+ T cells. We then searched for a soluble factor produced by mTECs able to increase IL-2 production by CD4+ cells and could identify the inducible T-cell costimulator ligand (ICOSL). Our data strongly suggest a « ménage à trois »: mTEC cells (via ICOSL) induce overproduction of IL-2 by CD25- T cells leading to the expansion of tTreg cells. Altogether, these results demonstrate for the first time a role of mTECs in promoting Treg cell expansion in the human thymus and implicate IL-2 and ICOSL in this process.
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50
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Yüksel M, Laukens D, Heindryckx F, Van Vlierberghe H, Geerts A, Wong FS, Wen L, Colle I. Hepatitis mouse models: from acute-to-chronic autoimmune hepatitis. Int J Exp Pathol 2014; 95:309-20. [PMID: 25112417 DOI: 10.1111/iep.12090] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Accepted: 06/04/2014] [Indexed: 12/13/2022] Open
Abstract
Autoimmune hepatitis (AIH) is a chronic inflammatory liver disease associated with interface hepatitis, raised plasma liver enzymes, the presence of autoantibodies and regulatory T-cell (Tregs) dysfunction. The clinical course is heterogeneous, manifested by a fulminant or indolent course. Although genetic predisposition is well accepted, the combination with currently undefined environmental factors is crucial for the development of the disease. Progress in the development of reliable animal models provides added understanding of the pathophysiology of AIH, and these will be very useful in evaluating potential therapeutics. It appears that artificially breaking tolerance in the liver is easy. However, maintaining this state of tolerance breakdown, to get chronic hepatitis, is difficult because liver immune homeostasis is strongly regulated by several immune response inhibitory mechanisms. For example, Tregs are crucial regulators in acute and chronic hepatitis, and C57BL/6 mice are most prone to experimental AIH. Immunization of C57BL/6 mice with liver (AIH) autoantigens (CYP2D6/FTCD or IL-4R) and the disturbance of liver regulatory mechanism(s), leading to experimental AIH, are likely to be most representative of human AIH pathology.
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Affiliation(s)
- Muhammed Yüksel
- Department of Hepatology and Gastroenterology, Ghent University, Ghent, Belgium; Department of Endocrinology, Yale School of Medicine, New Haven, CT, USA
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