1
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Groegler J, Callebaut A, James EA, Delong T. The insulin secretory granule is a hotspot for autoantigen formation in type 1 diabetes. Diabetologia 2024; 67:1507-1516. [PMID: 38811417 DOI: 10.1007/s00125-024-06164-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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Accepted: 03/11/2024] [Indexed: 05/31/2024]
Abstract
In type 1 diabetes, the insulin-producing beta cells of the pancreas are destroyed through the activity of autoreactive T cells. In addition to strong and well-documented HLA class II risk haplotypes, type 1 diabetes is associated with noncoding polymorphisms within the insulin gene locus. Furthermore, autoantibody prevalence data and murine studies implicate insulin as a crucial autoantigen for the disease. Studies identify secretory granules, where proinsulin is processed into mature insulin, stored and released in response to glucose stimulation, as a source of antigenic epitopes and neoepitopes. In this review, we integrate established concepts, including the role that susceptible HLA and thymic selection of the T cell repertoire play in setting the stage for autoimmunity, with emerging insights about beta cell and insulin secretory granule biology. In particular, the acidic, peptide-rich environment of secretory granules combined with its array of enzymes generates a distinct proteome that is unique to functional beta cells. These factors converge to generate non-templated peptide sequences that are recognised by autoreactive T cells. Although unanswered questions remain, formation and presentation of these epitopes and the resulting immune responses appear to be key aspects of disease initiation. In addition, these pathways may represent important opportunities for therapeutic intervention.
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Affiliation(s)
- Jason Groegler
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Aïsha Callebaut
- Center for Translational Immunology, Benaroya Research Institute, Seattle, WA, USA
| | - Eddie A James
- Center for Translational Immunology, Benaroya Research Institute, Seattle, WA, USA
| | - Thomas Delong
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
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2
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González-Moro I, Rojas-Márquez H, Sebastian-delaCruz M, Mentxaka-Salgado J, Olazagoitia-Garmendia A, Mendoza LM, Lluch A, Fantuzzi F, Lambert C, Ares Blanco J, Marselli L, Marchetti P, Cnop M, Delgado E, Fernández-Real JM, Ortega FJ, Castellanos-Rubio A, Santin I. A long non-coding RNA that harbors a SNP associated with type 2 diabetes regulates the expression of TGM2 gene in pancreatic beta cells. Front Endocrinol (Lausanne) 2023; 14:1101934. [PMID: 36824360 PMCID: PMC9941620 DOI: 10.3389/fendo.2023.1101934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Accepted: 01/24/2023] [Indexed: 02/10/2023] Open
Abstract
INTRODUCTION Most of the disease-associated single nucleotide polymorphisms (SNPs) lie in non- coding regions of the human genome. Many of these variants have been predicted to impact the expression and function of long non-coding RNAs (lncRNA), but the contribution of these molecules to the development of complex diseases remains to be clarified. METHODS Here, we performed a genetic association study between a SNP located in a lncRNA known as LncTGM2 and the risk of developing type 2 diabetes (T2D), and analyzed its implication in disease pathogenesis at pancreatic beta cell level. Genetic association study was performed on human samples linking the rs2076380 polymorphism with T2D and glycemic traits. The pancreatic beta cell line EndoC-bH1 was employed for functional studies based on LncTGM2 silencing and overexpression experiments. Human pancreatic islets were used for eQTL analysis. RESULTS We have identified a genetic association between LncTGM2 and T2D risk. Functional characterization of the LncTGM2 revealed its implication in the transcriptional regulation of TGM2, coding for a transglutaminase. The T2Dassociated risk allele in LncTGM2 disrupts the secondary structure of this lncRNA, affecting its stability and the expression of TGM2 in pancreatic beta cells. Diminished LncTGM2 in human beta cells impairs glucose-stimulated insulin release. CONCLUSIONS These findings provide novel information on the molecular mechanisms by which T2D-associated SNPs in lncRNAs may contribute to disease, paving the way for the development of new therapies based on the modulation of lncRNAs.
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Affiliation(s)
- Itziar González-Moro
- Department of Biochemistry and Molecular Biology, University of the Basque Country UPV/EHU, Leioa, Spain
- Biocruces Bizkaia Health Research Institute, Barakaldo, Spain
| | - Henar Rojas-Márquez
- Biocruces Bizkaia Health Research Institute, Barakaldo, Spain
- Department of Genetics, Physical Anthropology and Animal Physiology, University of the Basque Country, Leioa, Spain
| | - Maialen Sebastian-delaCruz
- Biocruces Bizkaia Health Research Institute, Barakaldo, Spain
- Department of Genetics, Physical Anthropology and Animal Physiology, University of the Basque Country, Leioa, Spain
| | - Jon Mentxaka-Salgado
- Department of Biochemistry and Molecular Biology, University of the Basque Country UPV/EHU, Leioa, Spain
- Biocruces Bizkaia Health Research Institute, Barakaldo, Spain
| | - Ane Olazagoitia-Garmendia
- Department of Biochemistry and Molecular Biology, University of the Basque Country UPV/EHU, Leioa, Spain
- Biocruces Bizkaia Health Research Institute, Barakaldo, Spain
- Department of Genetics, Physical Anthropology and Animal Physiology, University of the Basque Country, Leioa, Spain
| | - Luis Manuel Mendoza
- Department of Biochemistry and Molecular Biology, University of the Basque Country UPV/EHU, Leioa, Spain
- Biocruces Bizkaia Health Research Institute, Barakaldo, Spain
| | - Aina Lluch
- Institut d’Investigació Biomèdica de Girona, Girona, Spain
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Instituto de Salud Carlos III, Madrid, Spain
| | - Federica Fantuzzi
- ULB Center for Diabetes Research, Université Libre de Bruxelles, Brussels, Belgium
| | - Carmen Lambert
- Health Research Institute of the Principality of Asturias (ISPA), Oviedo, Spain
- University of Barcelona, Barcelona, Spain
| | - Jessica Ares Blanco
- Health Research Institute of the Principality of Asturias (ISPA), Oviedo, Spain
- Endocrinology and Nutrition Department, Central University Hospital of Asturias (HUCA), Oviedo, Spain
- Department of Medicine, University of Oviedo, Oviedo, Spain
| | - Lorella Marselli
- Department of Clinical and Experimental Medicine, Cisanello University Hospital, Pisa, Italy
| | - Piero Marchetti
- Department of Clinical and Experimental Medicine, Cisanello University Hospital, Pisa, Italy
| | - Miriam Cnop
- ULB Center for Diabetes Research, Université Libre de Bruxelles, Brussels, Belgium
- Division of Endocrinology, Erasmus Hospital, Université Libre de Bruxelles, Brussels, Belgium
| | - Elías Delgado
- Health Research Institute of the Principality of Asturias (ISPA), Oviedo, Spain
- Endocrinology and Nutrition Department, Central University Hospital of Asturias (HUCA), Oviedo, Spain
- Department of Medicine, University of Oviedo, Oviedo, Spain
- Spanish Biomedical Research Network in Rare Diseases (CIBERER), Madrid, Spain
| | - José Manuel Fernández-Real
- Institut d’Investigació Biomèdica de Girona, Girona, Spain
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Instituto de Salud Carlos III, Madrid, Spain
- Department of Medical Sciences, School of Medicine, University of Girona, Oviedo, Spain
| | - Francisco José Ortega
- Institut d’Investigació Biomèdica de Girona, Girona, Spain
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Instituto de Salud Carlos III, Madrid, Spain
| | - Ainara Castellanos-Rubio
- Biocruces Bizkaia Health Research Institute, Barakaldo, Spain
- Department of Genetics, Physical Anthropology and Animal Physiology, University of the Basque Country, Leioa, Spain
- Diabetes and Associated Metabolic Diseases Networking Biomedical Research Centre, Madrid, Spain
- Ikerbasque - Basque Foundation for Science, Bilbao, Spain
- *Correspondence: Izortze Santin, ; Ainara Castellanos-Rubio,
| | - Izortze Santin
- Department of Biochemistry and Molecular Biology, University of the Basque Country UPV/EHU, Leioa, Spain
- Biocruces Bizkaia Health Research Institute, Barakaldo, Spain
- Diabetes and Associated Metabolic Diseases Networking Biomedical Research Centre, Madrid, Spain
- *Correspondence: Izortze Santin, ; Ainara Castellanos-Rubio,
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3
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Canella R, Brugnoli F, Gallo M, Keillor JW, Terrazzan A, Ferrari E, Grassilli S, Gates EWJ, Volinia S, Bertagnolo V, Bianchi N, Bergamini CM. A Multidisciplinary Approach Establishes a Link between Transglutaminase 2 and the Kv10.1 Voltage-Dependent K + Channel in Breast Cancer. Cancers (Basel) 2022; 15:cancers15010178. [PMID: 36612174 PMCID: PMC9818547 DOI: 10.3390/cancers15010178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 12/15/2022] [Accepted: 12/24/2022] [Indexed: 12/29/2022] Open
Abstract
Since the multifunctionality of transglutaminase 2 (TG2) includes extra- and intracellular functions, we investigated the effects of intracellular administration of TG2 inhibitors in three breast cancer cell lines, MDA-MB-231, MDA-MB-436 and MDA-MB-468, which are representative of different triple-negative phenotypes, using a patch-clamp technique. The first cell line has a highly voltage-dependent a membrane current, which is low in the second and almost absent in the third one. While applying a voltage protocol to responsive single cells, injection of TG2 inhibitors triggered a significant decrease of the current in MDA-MB-231 that we attributed to voltage-dependent K+ channels using the specific inhibitors 4-aminopyridine and astemizole. Since the Kv10.1 channel plays a dominant role as a marker of cell migration and survival in breast cancer, we investigated its relationship with TG2 by immunoprecipitation. Our data reveal their physical interaction affects membrane currents in MDA-MB-231 but not in the less sensitive MDA-MB-436 cells. We further correlated the efficacy of TG2 inhibition with metabolic changes in the supernatants of treated cells, resulting in increased concentration of methyl- and dimethylamines, representing possible response markers. In conclusion, our findings highlight the interference of TG2 inhibitors with the Kv10.1 channel as a potential therapeutic tool depending on the specific features of cancer cells.
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Affiliation(s)
- Rita Canella
- Department of Neuroscience and Rehabilitation, University of Ferrara, 44121 Ferrara, Italy
| | - Federica Brugnoli
- Department of Translational Medicine, University of Ferrara, 44121 Ferrara, Italy
| | - Mariana Gallo
- Department of Medicine and Surgery, University of Parma, 43125 Parma, Italy
| | - Jeffrey W. Keillor
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - Anna Terrazzan
- Department of Translational Medicine, University of Ferrara, 44121 Ferrara, Italy
| | - Elena Ferrari
- Department of Medicine and Surgery, University of Parma, 43125 Parma, Italy
| | - Silvia Grassilli
- Department of Translational Medicine, University of Ferrara, 44121 Ferrara, Italy
| | - Eric W. J. Gates
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - Stefano Volinia
- Department of Translational Medicine, University of Ferrara, 44121 Ferrara, Italy
| | - Valeria Bertagnolo
- Department of Translational Medicine, University of Ferrara, 44121 Ferrara, Italy
| | - Nicoletta Bianchi
- Department of Translational Medicine, University of Ferrara, 44121 Ferrara, Italy
- Correspondence: ; Tel.: +39-0532-455854
| | - Carlo M. Bergamini
- Department of Neuroscience and Rehabilitation, University of Ferrara, 44121 Ferrara, Italy
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4
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Callebaut A, Bruggeman Y, Zamit C, Sodré FMC, Irla M, Mathieu C, Buitinga M, Overbergh L. Aberrant expression of transglutaminase 2 in pancreas and thymus of NOD mice underscores the importance of deamidation in neoantigen generation. Front Endocrinol (Lausanne) 2022; 13:908248. [PMID: 35966081 PMCID: PMC9367685 DOI: 10.3389/fendo.2022.908248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 07/06/2022] [Indexed: 11/17/2022] Open
Abstract
Post-translational modifications can lead to a break in immune tolerance in autoimmune diseases such as type 1 diabetes (T1D). Deamidation, the conversion of glutamine to glutamic acid by transglutaminase (TGM) enzymes, is a post-translational modification of interest, with deamidated peptides being reported as autoantigens in T1D. However, little is known about how Tgm2, the most ubiquitously expressed Tgm isoform, is regulated and how tolerance against deamidated peptides is lost. Here, we report on the aberrant expression and regulation of Tgm2 in the pancreas and thymus of NOD mice. We demonstrate that Tgm2 expression is induced by the inflammatory cytokines IL1β and IFNγ in a synergistic manner and that murine pancreatic islets of NOD mice have higher Tgm2 levels, while Tgm2 levels in medullary thymic epithelial cells are reduced. We thus provide the first direct evidence to our knowledge that central tolerance establishment against deamidated peptides might be impaired due to lower Tgm2 expression in NOD medullary thymic epithelial cells, which together with the aberrantly high levels of deamidated peptides in NOD β-cells underscores the role of deamidation in amplifying T-cell reactivity.
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Affiliation(s)
- Aїsha Callebaut
- Laboratory of Clinical and Experimental Endocrinology, Department of Chronic Diseases and Metabolism, KU Leuven, Leuven, Belgium
| | - Ylke Bruggeman
- Laboratory of Clinical and Experimental Endocrinology, Department of Chronic Diseases and Metabolism, KU Leuven, Leuven, Belgium
| | - Cloé Zamit
- CNRS, INSERM, Centre d’Immunologie de Marseille-Luminy, Aix-Marseille University, Marseille, France
| | - Fernanda Marques Câmara Sodré
- Laboratory of Clinical and Experimental Endocrinology, Department of Chronic Diseases and Metabolism, KU Leuven, Leuven, Belgium
- Department of Microbiology, University of Sao Paulo, Sao Paulo, Brazil
| | - Magali Irla
- CNRS, INSERM, Centre d’Immunologie de Marseille-Luminy, Aix-Marseille University, Marseille, France
| | - Chantal Mathieu
- Laboratory of Clinical and Experimental Endocrinology, Department of Chronic Diseases and Metabolism, KU Leuven, Leuven, Belgium
| | - Mijke Buitinga
- Laboratory of Clinical and Experimental Endocrinology, Department of Chronic Diseases and Metabolism, KU Leuven, Leuven, Belgium
- Department of Nutrition and Movement Sciences, Maastricht University, Maastricht, Netherlands
- Department of Radiology and Nuclear Medicine, Maastricht University Medical Center, Maastricht, Netherlands
| | - Lut Overbergh
- Laboratory of Clinical and Experimental Endocrinology, Department of Chronic Diseases and Metabolism, KU Leuven, Leuven, Belgium
- *Correspondence: Lut Overbergh,
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5
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Toren E, Burnette KS, Banerjee RR, Hunter CS, Tse HM. Partners in Crime: Beta-Cells and Autoimmune Responses Complicit in Type 1 Diabetes Pathogenesis. Front Immunol 2021; 12:756548. [PMID: 34691077 PMCID: PMC8529969 DOI: 10.3389/fimmu.2021.756548] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Accepted: 09/13/2021] [Indexed: 12/11/2022] Open
Abstract
Type 1 diabetes (T1D) is an autoimmune disease characterized by autoreactive T cell-mediated destruction of insulin-producing pancreatic beta-cells. Loss of beta-cells leads to insulin insufficiency and hyperglycemia, with patients eventually requiring lifelong insulin therapy to maintain normal glycemic control. Since T1D has been historically defined as a disease of immune system dysregulation, there has been little focus on the state and response of beta-cells and how they may also contribute to their own demise. Major hurdles to identifying a cure for T1D include a limited understanding of disease etiology and how functional and transcriptional beta-cell heterogeneity may be involved in disease progression. Recent studies indicate that the beta-cell response is not simply a passive aspect of T1D pathogenesis, but rather an interplay between the beta-cell and the immune system actively contributing to disease. Here, we comprehensively review the current literature describing beta-cell vulnerability, heterogeneity, and contributions to pathophysiology of T1D, how these responses are influenced by autoimmunity, and describe pathways that can potentially be exploited to delay T1D.
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Affiliation(s)
- Eliana Toren
- Department of Medicine, Division of Endocrinology Diabetes and Metabolism, University of Alabama at Birmingham, Birmingham, AL, United States
- Comprehensive Diabetes Center, University of Alabama at Birmingham, Birmingham, AL, United States
| | - KaLia S. Burnette
- Comprehensive Diabetes Center, University of Alabama at Birmingham, Birmingham, AL, United States
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Ronadip R. Banerjee
- Division of Endocrinology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Chad S. Hunter
- Department of Medicine, Division of Endocrinology Diabetes and Metabolism, University of Alabama at Birmingham, Birmingham, AL, United States
- Comprehensive Diabetes Center, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Hubert M. Tse
- Comprehensive Diabetes Center, University of Alabama at Birmingham, Birmingham, AL, United States
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, United States
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6
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Coeliac disease in children with type 1 diabetes. THE LANCET CHILD & ADOLESCENT HEALTH 2018; 2:133-143. [DOI: 10.1016/s2352-4642(17)30172-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2017] [Revised: 10/13/2017] [Accepted: 10/27/2017] [Indexed: 12/17/2022]
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7
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Marré ML, Piganelli JD. Environmental Factors Contribute to β Cell Endoplasmic Reticulum Stress and Neo-Antigen Formation in Type 1 Diabetes. Front Endocrinol (Lausanne) 2017; 8:262. [PMID: 29033899 PMCID: PMC5626851 DOI: 10.3389/fendo.2017.00262] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Accepted: 09/20/2017] [Indexed: 12/16/2022] Open
Abstract
Type 1 diabetes (T1D) is an autoimmune disease in which immune-mediated targeting and destruction of insulin-producing pancreatic islet β cells leads to chronic hyperglycemia. There are many β cell proteins that are targeted by autoreactive T cells in their native state. However, recent studies have demonstrated that many β cell proteins are recognized as neo-antigens following posttranslational modification (PTM). Although modified neo-antigens are well-established targets of pathology in other autoimmune diseases, the effects of neo-antigens in T1D progression and the mechanisms by which they are generated are not well understood. We have demonstrated that PTM occurs during endoplasmic reticulum (ER) stress, a process to which β cells are uniquely susceptible due to the high rate of insulin production in response to dynamic glucose sensing. In the context of genetic susceptibility to autoimmunity, presentation of these modified neo-antigens may activate autoreactive T cells and cause pathology. However, inherent β cell ER stress and protein PTM do not cause T1D in every genetically susceptible individual, suggesting the contribution of additional factors. Indeed, many environmental factors, such as viral infection, chemicals, or inflammatory cytokines, are associated with T1D onset, but the mechanisms by which these factors lead to disease onset remain unknown. Since these environmental factors also cause ER stress, exposure to these factors may enhance production of neo-antigens, therefore boosting β cell recognition by autoreactive T cells and exacerbating T1D pathogenesis. Therefore, the combined effects of physiological ER stress and the stress that is induced by environmental factors may lead to breaks in peripheral tolerance, contribute to antigen spread, and hasten disease onset. This Hypothesis and Theory article summarizes what is currently known about ER stress and protein PTM in autoimmune diseases including T1D and proposes a role for environmental factors in breaking immune tolerance to β cell antigens through neo-antigen formation.
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Affiliation(s)
- Meghan L Marré
- Division of Pediatric Surgery, Department of Surgery, Children's Hospital of Pittsburgh, University of Pittsburgh, Pittsburgh, PA, United States
| | - Jon D Piganelli
- Division of Pediatric Surgery, Department of Surgery, Children's Hospital of Pittsburgh, University of Pittsburgh, Pittsburgh, PA, United States
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8
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Lai TS, Lin CJ, Greenberg CS. Role of tissue transglutaminase-2 (TG2)-mediated aminylation in biological processes. Amino Acids 2016; 49:501-515. [PMID: 27270573 DOI: 10.1007/s00726-016-2270-8] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 05/31/2016] [Indexed: 01/08/2023]
Abstract
Post-translational modification (PTM) is an important mechanism in modulating a protein's structure and can lead to substantial diversity in biological function. Compared to other forms of PTMs such as phosphorylation, acetylation and glycosylation, the physiological significance of aminylation is limited. Aminylation refers to the covalent incorporation of biogenic/polyamines into target protein by calcium-dependent transglutaminases (TGs). The development of novel and more sensitive techniques has led to more proteins identified as tissue transglutaminase (TG2) substrates and potential targets for aminylation. Many of these substrate proteins play a role in cell signaling, cytoskeleton organization, muscle contraction, and inflammation. TG2 is well studied and widely expressed in a variety of tissues and will be the primary focus of this review on recent advance in transglutaminase-mediated aminylation.
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Affiliation(s)
- Thung-S Lai
- Graduate Institute of Biomedical Science, Mackay Medical College, No. 46, Sec. 3, Jhong-Jheng Rd., Sanzhi Dist, New Taipei City, 25200, Taiwan, ROC.
| | - Cheng-Jui Lin
- Nephrology/Department of Internal Medicine, Mackay Memorial Hospital, Taipei, Taiwan, ROC
- Nursing and Management, Mackay Junior College of Medicine, Taipei, Taiwan, ROC
| | - Charles S Greenberg
- Department of Medicine, Medical University of South Carolina, Charleston, SC, 29425, USA
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9
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McLaughlin RJ, de Haan A, Zaldumbide A, de Koning EJ, de Ru AH, van Veelen PA, van Lummel M, Roep BO. Human islets and dendritic cells generate post-translationally modified islet autoantigens. Clin Exp Immunol 2016; 185:133-40. [PMID: 26861694 DOI: 10.1111/cei.12775] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 01/15/2016] [Accepted: 02/07/2016] [Indexed: 12/14/2022] Open
Abstract
The initiation of type 1 diabetes (T1D) requires a break in peripheral tolerance. New insights into neoepitope formation indicate that post-translational modification of islet autoantigens, for example via deamidation, may be an important component of disease initiation or exacerbation. Indeed, deamidation of islet autoantigens increases their binding affinity to the T1D highest-risk human leucocyte antigen (HLA) haplotypes HLA-DR3/DQ2 and -DR4/DQ8, increasing the chance that T cells reactive to deamidated autoantigens can be activated upon T cell receptor ligation. Here we investigated human pancreatic islets and inflammatory and tolerogenic human dendritic cells (DC and tolDC) as potential sources of deamidated islet autoantigens and examined whether deamidation is altered in an inflammatory environment. Islets, DC and tolDC contained tissue transglutaminase, the key enzyme responsible for peptide deamidation, and enzyme activity increased following an inflammatory insult. Islets treated with inflammatory cytokines were found to contain deamidated insulin C-peptide. DC, heterozygous for the T1D highest-risk DQ2/8, pulsed with native islet autoantigens could present naturally processed deamidated neoepitopes. HLA-DQ2 or -DQ8 homozygous DC did not present deamidated islet peptides. This study identifies both human islets and DC as sources of deamidated islet autoantigens and implicates inflammatory activation of tissue transglutaminase as a potential mechanism for islet and DC deamidation.
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Affiliation(s)
- R J McLaughlin
- Department of Immunohematology and Blood Transfusion, Leiden, the Netherlands
| | - A de Haan
- Department of Immunohematology and Blood Transfusion, Leiden, the Netherlands
| | - A Zaldumbide
- Department of Molecular Cell Biology, Leiden, the Netherlands
| | - E J de Koning
- Department of Nephrology, Leiden University Medical Center, Leiden, the Netherlands
| | - A H de Ru
- Department of Immunohematology and Blood Transfusion, Leiden, the Netherlands
| | - P A van Veelen
- Department of Immunohematology and Blood Transfusion, Leiden, the Netherlands
| | - M van Lummel
- Department of Immunohematology and Blood Transfusion, Leiden, the Netherlands
| | - B O Roep
- Department of Immunohematology and Blood Transfusion, Leiden, the Netherlands.,Department of Diabetes Immunology, Diabetes and Metabolism Research Institute at the Beckman Research Institute of the City of Hope, Duarte, CA, USA
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10
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Marré ML, Profozich JL, Coneybeer JT, Geng X, Bertera S, Ford MJ, Trucco M, Piganelli JD. Inherent ER stress in pancreatic islet β cells causes self-recognition by autoreactive T cells in type 1 diabetes. J Autoimmun 2016; 72:33-46. [PMID: 27173406 DOI: 10.1016/j.jaut.2016.04.009] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Revised: 04/25/2016] [Accepted: 04/30/2016] [Indexed: 01/10/2023]
Abstract
Type 1 diabetes (T1D) is an autoimmune disease characterized by pancreatic β cell destruction induced by islet reactive T cells that have escaped central tolerance. Many physiological and environmental triggers associated with T1D result in β cell endoplasmic reticulum (ER) stress and dysfunction, increasing the potential for abnormal post-translational modification (PTM) of proteins. We hypothesized that β cell ER stress induced by environmental and physiological conditions generates abnormally-modified proteins for the T1D autoimmune response. To test this hypothesis we exposed the murine CD4(+) diabetogenic BDC2.5 T cell clone to murine islets in which ER stress had been induced chemically (Thapsigargin). The BDC2.5 T cell IFNγ response to these cells was significantly increased compared to non-treated islets. This β cell ER stress increased activity of the calcium (Ca(2+))-dependent PTM enzyme tissue transglutaminase 2 (Tgase2), which was necessary for full stress-dependent immunogenicity. Indeed, BDC2.5 T cells responded more strongly to their antigen after its modification by Tgase2. Finally, exposure of non-antigenic murine insulinomas to chemical ER stress in vitro or physiological ER stress in vivo caused increased ER stress and Tgase2 activity, culminating in higher BDC2.5 responses. Thus, β cell ER stress induced by chemical and physiological triggers leads to β cell immunogenicity through Ca(2+)-dependent PTM. These findings elucidate a mechanism of how β cell proteins are modified and become immunogenic, and reveal a novel opportunity for preventing β cell recognition by autoreactive T cells.
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MESH Headings
- Amino Acid Sequence
- Animals
- Autoantigens/genetics
- Autoantigens/immunology
- Autoimmunity/genetics
- Autoimmunity/immunology
- Blotting, Western
- CD4-Positive T-Lymphocytes/immunology
- CD4-Positive T-Lymphocytes/metabolism
- Calcium/immunology
- Calcium/metabolism
- Cell Line
- Cells, Cultured
- Chromogranin A/genetics
- Chromogranin A/immunology
- Chromogranin A/metabolism
- Diabetes Mellitus, Type 1/genetics
- Diabetes Mellitus, Type 1/immunology
- Diabetes Mellitus, Type 1/metabolism
- Endoplasmic Reticulum Stress/genetics
- Endoplasmic Reticulum Stress/immunology
- GTP-Binding Proteins/genetics
- GTP-Binding Proteins/immunology
- GTP-Binding Proteins/metabolism
- Humans
- Insulin-Secreting Cells/immunology
- Insulin-Secreting Cells/metabolism
- Mice, Inbred BALB C
- Mice, Inbred C57BL
- Mice, Inbred NOD
- Mice, SCID
- Models, Immunological
- Protein Glutamine gamma Glutamyltransferase 2
- Protein Processing, Post-Translational/immunology
- Reverse Transcriptase Polymerase Chain Reaction
- Tandem Mass Spectrometry
- Transglutaminases/genetics
- Transglutaminases/immunology
- Transglutaminases/metabolism
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Affiliation(s)
- Meghan L Marré
- Division of Immunogenetics, Department of Pediatrics, Children's Hospital of Pittsburgh, University of Pittsburgh School of Medicine, 4401 Penn Avenue, Pittsburgh, PA 15224, USA
| | - Jennifer L Profozich
- Division of Immunogenetics, Department of Pediatrics, Children's Hospital of Pittsburgh, University of Pittsburgh School of Medicine, 4401 Penn Avenue, Pittsburgh, PA 15224, USA
| | - Jorge T Coneybeer
- Division of Immunogenetics, Department of Pediatrics, Children's Hospital of Pittsburgh, University of Pittsburgh School of Medicine, 4401 Penn Avenue, Pittsburgh, PA 15224, USA
| | - Xuehui Geng
- Division of Immunogenetics, Department of Pediatrics, Children's Hospital of Pittsburgh, University of Pittsburgh School of Medicine, 4401 Penn Avenue, Pittsburgh, PA 15224, USA
| | - Suzanne Bertera
- Division of Immunogenetics, Department of Pediatrics, Children's Hospital of Pittsburgh, University of Pittsburgh School of Medicine, 4401 Penn Avenue, Pittsburgh, PA 15224, USA
| | - Michael J Ford
- MS Bioworks, LLC, 3950 Varsity Drive, Ann Arbor, MI 48108, USA
| | - Massimo Trucco
- Division of Immunogenetics, Department of Pediatrics, Children's Hospital of Pittsburgh, University of Pittsburgh School of Medicine, 4401 Penn Avenue, Pittsburgh, PA 15224, USA
| | - Jon D Piganelli
- Division of Immunogenetics, Department of Pediatrics, Children's Hospital of Pittsburgh, University of Pittsburgh School of Medicine, 4401 Penn Avenue, Pittsburgh, PA 15224, USA.
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11
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Marré ML, James EA, Piganelli JD. β cell ER stress and the implications for immunogenicity in type 1 diabetes. Front Cell Dev Biol 2015; 3:67. [PMID: 26579520 PMCID: PMC4621612 DOI: 10.3389/fcell.2015.00067] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 10/08/2015] [Indexed: 12/11/2022] Open
Abstract
Type 1 diabetes (T1D) is a chronic autoimmune disease characterized by hyperglycemia due to progressive immune-mediated destruction of insulin-producing pancreatic islet β cells. Although many elegant studies have identified β cell autoantigens that are targeted by the autoimmune response, the mechanisms by which these autoantigens are generated remain poorly understood. Normal β cell physiology includes a high demand for insulin production and secretion in response to dynamic glucose sensing. This secretory function predisposes β cells to significantly higher levels of endoplasmic reticulum (ER) stress compared to nonsecretory cells. In addition, many environmental triggers associated with T1D onset further augment this inherent ER stress in β cells. ER stress may increase abnormal post-translational modification (PTM) of endogenous β cell proteins. Indeed, in other autoimmune disorders such as celiac disease, systemic lupus erythematosus, multiple sclerosis, and rheumatoid arthritis, abnormally modified neo-antigens are presented by antigen presenting cells (APCs) in draining lymph nodes. In the context of genetic susceptibility to autoimmunity, presentation of neo-antigens activates auto-reactive T cells and pathology ensues. Therefore, the ER stress induced by normal β cell secretory physiology and environmental triggers may be sufficient to generate neo-antigens for the autoimmune response in T1D. This review summarizes what is currently known about ER stress and protein PTM in target organs of other autoimmune disease models, as well as the data supporting a role for ER stress-induced neo-antigen formation in β cells in T1D.
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Affiliation(s)
- Meghan L Marré
- Division of Pediatric Surgery, Department of Surgery, Children's Hospital of Pittsburgh, University of Pittsburgh Pittsburgh, PA, USA
| | - Eddie A James
- Benaroya Research Institute at Virginia Mason Seattle, WA, USA
| | - Jon D Piganelli
- Division of Pediatric Surgery, Department of Surgery, Children's Hospital of Pittsburgh, University of Pittsburgh Pittsburgh, PA, USA
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12
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van Lummel M, Duinkerken G, van Veelen PA, de Ru A, Cordfunke R, Zaldumbide A, Gomez-Touriño I, Arif S, Peakman M, Drijfhout JW, Roep BO. Posttranslational modification of HLA-DQ binding islet autoantigens in type 1 diabetes. Diabetes 2014; 63:237-47. [PMID: 24089515 DOI: 10.2337/db12-1214] [Citation(s) in RCA: 135] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Posttranslational modification (PTM) of islet autoantigens can cause lack of central tolerance in type 1 diabetes (T1D). Tissue transglutaminase (tTG), involved in PTM of gluten antigens in celiac disease, creates negatively charged peptides favored by T1D-predisposing HLA-DQ molecules, offering an attractive candidate modifying islet autoantigens in T1D. The highly predisposing HLA-DQ8cis/trans molecules share preferences for negatively charged peptides, as well as distinct peptide-binding characteristics that distinguish their peptide-binding repertoire. We screened islet autoantigens with the tTG substrate motif for candidate-modified epitopes binding to HLA-DQ8cis/trans and identified 31 candidate islet epitopes. Deamidation was confirmed for 28 peptides (90%). Two of these epitopes preferentially bound to HLA-DQ8cis and six to HLA-DQ8trans upon deamidation, whereas all other peptides bound equally to HLA-DQ8cis/trans. HLA-DQ8cis-restricted T cells from a new-onset T1D patient could only be generated against a deamidated proinsulin peptide, but cross-reacted with native proinsulin peptide upon restimulation. The rate of T-cell autoreactivity in recent-onset T1D patients extended from 42% to native insulin to 68% adding responses to modified proinsulin, versus 20% and 37% respectively, in healthy donors. Most patients responded by interferon-γ, whereas most healthy donors produced interleukin-10 only. Thus, T-cell autoreactivity exists to modified islet epitopes that differs in quality and quantity between patients and healthy donors.
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Affiliation(s)
- Menno van Lummel
- Department of Immunohematology and Blood Transfusion, Leiden University Medical Center, Leiden, the Netherlands
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13
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Sileno S, D'Oria V, Stucchi R, Alessio M, Petrini S, Bonetto V, Maechler P, Bertuzzi F, Grasso V, Paolella K, Barbetti F, Massa O. A possible role of transglutaminase 2 in the nucleus of INS-1E and of cells of human pancreatic islets. J Proteomics 2013; 96:314-27. [PMID: 24291354 PMCID: PMC3919173 DOI: 10.1016/j.jprot.2013.11.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Revised: 10/16/2013] [Accepted: 11/12/2013] [Indexed: 12/26/2022]
Abstract
Transglutaminase 2 (TG2) is a multifunctional protein with Ca2 +-dependent transamidating and G protein activity. Previously we reported that the role of TG2 in insulin secretion may involve cytoplasmic actin remodeling and a regulative action on other proteins during granule movement. The aim of this study was to gain a better insight into the role of TG2 transamidating activity in mitochondria and in the nucleus of INS-1E rat insulinoma cell line (INS-1E) during insulin secretion. To this end we labeled INS-1E with an artificial donor (biotinylated peptide), in basal condition and after stimulus with glucose for 2, 5, and 8 min. Biotinylated proteins of the nuclear/mitochondrial-enriched fraction were analyzed using two-dimensional electrophoresis and mass spectrometry. Many mitochondrial proteins involved in Ca2 + homeostasis (e.g. voltage-dependent anion-selective channel protein, prohibitin and different ATP synthase subunits) and many nuclear proteins involved in gene regulation (e.g. histone H3, barrier to autointegration factor and various heterogeneous nuclear ribonucleoprotein) were identified among a number of transamidating substrates of TG2 in INS-1E. The combined results provide evidence that a temporal link exists between glucose-stimulation, first phase insulin secretion and the action of TG on histone H3 both in INS-1E and human pancreatic islets. Biological significance Research into the role of transglutaminase 2 during insulin secretion in INS-1E rat insulinoma cellular model is depicting a complex role for this enzyme. Transglutaminase 2 acts in the different INS-1E compartments in the same way: catalyzing a post-translational modification event of its substrates. In this work we identify some mitochondrial and nuclear substrates of INS-1E during first phase insulin secretion. The finding that TG2 interacts with nuclear proteins that include BAF and histone H3 immediately after (2–5 min) glucose stimulus of INS-1E suggests that TG2 may be involved not only in insulin secretion, as suggested by our previous studies in cytoplasmic INS-1E fraction, but also in the regulation of glucose-induced gene transcription. Transglutaminase 2 localizes in the nucleus and in the mitochondrion of INS-1E. TG2 acts as a modifying enzyme in both compartments during FPIS. TG2 may contribute to Ca2 + sensing in mitochondrion through its substrates. TG2 may contribute to chromatin condensation in nucleus through its substrates.
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Affiliation(s)
- Sara Sileno
- Research Laboratories, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Valentina D'Oria
- Confocal Microscopy Core Facility, Research Laboratory, Bambino Gesù Children's Hospital, IRCSS, Rome, Italy
| | - Riccardo Stucchi
- Dulbecco Telethon Institute at IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, Milano, Italy
| | - Massimo Alessio
- Proteome Biochemistry Unit, San Raffaele Scientific Institute, Milan, Italy
| | - Stefania Petrini
- Confocal Microscopy Core Facility, Research Laboratory, Bambino Gesù Children's Hospital, IRCSS, Rome, Italy
| | - Valentina Bonetto
- Dulbecco Telethon Institute at IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, Milano, Italy
| | - Pierre Maechler
- Department of Cell Physiology and Metabolism, Geneva University Medical Centre, Geneva 4, Switzerland
| | | | - Valeria Grasso
- Research Laboratories, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Katia Paolella
- Dulbecco Telethon Institute at IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, Milano, Italy
| | - Fabrizio Barbetti
- Research Laboratories, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy; Department of Experimental Medicine and Surgery, University of Tor Vergata, Rome, Italy
| | - Ornella Massa
- Research Laboratories, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy.
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14
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Massa O, Alessio M, Russo L, Nardo G, Bonetto V, Bertuzzi F, Paladini A, Iafusco D, Patera P, Federici G, Not T, Tiberti C, Bonfanti R, Barbetti F. Serological Proteome Analysis (SERPA) as a tool for the identification of new candidate autoantigens in type 1 diabetes. J Proteomics 2013; 82:263-73. [PMID: 23500132 DOI: 10.1016/j.jprot.2013.02.030] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2012] [Revised: 02/26/2013] [Accepted: 02/27/2013] [Indexed: 01/28/2023]
Abstract
UNLABELLED Type 1 diabetes (T1D) is an autoimmune disease characterized by the presence of circulating autoantibodies directed against proteins of islet beta-cell. Autoantibody testing is used for diagnostic purposes; however, up to 2-5% of patients who are clinically diagnosed with T1D are found negative for known antibodies, suggesting that the T1D autoantigen panel is incomplete. With the aim of identifying new T1D autoantigen(s), we used sera from subjects clinically diagnosed with T1D, but who tested negative for the four T1D autoantibodies currently used in clinical practice and for genes responsible for sporadic cases of diabetes. Sera from these patients were challenged by Western blot against the proteome from human pancreatic beta-cells resolved by 2DE. Eleven proteins were identified by MS. A radiobinding assay (RBA) was developed to test the reactivity to Rab GDP dissociation inhibitor beta (GDIβ) of T1D sera using an independent method. Depending on the construct used (open reading frame or COOH-terminus) 22% to 32% of fifty T1D sera showed increased binding to GDIβ by RBA. In addition, 15% of patients with celiac disease had raised binding to the COOH-terminus GDIβ. These results indicate that immunoproteomics is a feasible strategy for the identification of candidate T1D autoantigens. BIOLOGICAL SIGNIFICANCE Several approaches have been previously used to look for new type 1 diabetes autoantigens. With the present work we show that carefully selected sera from rare patients with diabetes both negative for the 5 autoantibodies currently used in clinical practice and for genes responsible for sporadic cases of diabetes, may be exploited in experiments utilizing human pancreatic islets extracts as a target for SERPA to identify novel candidate T1D autoantigens.
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Affiliation(s)
- Ornella Massa
- Laboratory of Mendelian Diabetes, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
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15
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Delong T, Baker RL, He J, Barbour G, Bradley B, Haskins K. Diabetogenic T-cell clones recognize an altered peptide of chromogranin A. Diabetes 2012; 61:3239-46. [PMID: 22912420 PMCID: PMC3501882 DOI: 10.2337/db12-0112] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Chromogranin A (ChgA) has been identified as the antigen target for three NOD-derived, diabetogenic CD4 T-cell clones, including the well-known BDC-2.5. These T-cell clones respond weakly to the peptide WE14, a naturally occurring proteolytic cleavage product from ChgA. We show here that WE14 can be converted into a highly antigenic T-cell epitope through treatment with the enzyme transglutaminase (TGase). The WE14 responses of three NOD-derived CD4 T-cell clones, each with different T-cell receptors (TCRs), and of T cells from BDC-2.5 TCR transgenic mice are increased after TGase conversion of the peptide. Primary CD4 T cells isolated from NOD mice also respond to high concentrations of WE14 and significantly lower concentrations of TGase-treated WE14. We hypothesize that posttranslational modification plays a critical role in the generation of T-cell epitopes in type 1 diabetes.
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16
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Abstract
Many of the best-studied actin regulatory proteins use non-covalent means to modulate the properties of actin. Yet, actin is also susceptible to covalent modifications of its amino acids. Recent work is increasingly revealing that actin processing and its covalent modifications regulate important cellular events. In addition, numerous pathogens express enzymes that specifically use actin as a substrate to regulate their hosts' cells. Actin post-translational alterations have been linked to different normal and disease processes and the effects associated with metabolic and environmental stressors. Herein, we highlight specific co-translational and post-translational modifications of actin and discuss the current understanding of the role that these modifications play in regulating actin.
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Affiliation(s)
- Jonathan R Terman
- Department of Neuroscience, The University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
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