Alternative Splicing and Differential Expression of the Islet Autoantigen IGRP Between Pancreas and Thymus Contributes to Immunogenicity of Pancreatic Islets but Not Diabetogenicity in Humans

Overview

Journal Diabetologia

Specialty Endocrinology

Date 2013 Sep 14

PMID 24030068

Citations 17

Authors

V Martijn de Jong

Joana R F Abreu

Annemarie A Verrijn Stuart

Arno R van der Slik

Katrijn Verhaeghen

Marten A Engelse

Bianca Blom

Frank J T Staal

Frans K Gorus

Bart O Roep

Affiliations

Soon will be listed here.

Abstract

Aims/hypothesis: Thymic expression of self-antigens during T-lymphocyte development is believed to be crucial for preventing autoimmunity. It has been suggested that G6PC2, the gene encoding islet-specific glucose-6-phosphatase catalytic subunit-related protein (IGRP), is differentially spliced between pancreatic beta cells and the thymus. This may contribute to incomplete elimination of IGRP-specific T lymphocytes in the thymus, predisposing individuals to type 1 diabetes. We tested whether specific splice variation in islets vs thymus correlates with loss of tolerance to IGRP in type 1 diabetes.

Methods: Expression of G6PC2 splice variants was compared among thymus, purified medullary thymic epithelial cells and pancreatic islets by RT-PCR. Differential immunogenicity of IGRP splice variants was tested in patients and healthy individuals for autoantibodies and specific cytotoxic T lymphocytes using radiobinding assays and HLA class I multimers, respectively.

Results: Previously reported G6PC2 splice variants, including full-length G6PC2, were confirmed, albeit that they occurred in both pancreas and thymus, rather than islets alone. Yet, their expression levels were profoundly greater in islets than in thymus. Moreover, three novel G6PC2 variants were discovered that occur in islets only, leading to protein truncations, frame shifts and neo-sequences prone to immunogenicity. However, autoantibodies to novel or known IGRP splice variants did not differ between patients and healthy individuals, and similar frequencies of IGRP-specific cytotoxic T lymphocytes could be detected in both patients with type 1 diabetes and healthy individuals.

Conclusions/interpretation: We propose that post-transcriptional variation of tissue-specific self-proteins may affect negative thymic selection, although this need not necessarily lead to disease.

Citing Articles

Theoretical Studies of DNA Microarray Present Potential Molecular and Cellular Interconnectivity of Signaling Pathways in Immune System Dysregulation.

Garcia J, Tayo L Genes (Basel). 2024; 15(4).

PMID: 38674328 PMC: 11049615. DOI: 10.3390/genes15040393.

Expanding the repertoire reveals recurrent, cryptic, and hematopoietic HLA class I minor histocompatibility antigens.

Fuchs K, van de Meent M, Honders M, Khatri I, Kester M, Koster E Blood. 2024; 143(18):1856-1872.

PMID: 38427583 PMC: 11076866. DOI: 10.1182/blood.2023022343.

Presence of immunogenic alternatively spliced insulin gene product in human pancreatic delta cells.

van Tienhoven R, Kracht M, van der Slik A, Thomaidou S, Wolters A, Giepmans B Diabetologia. 2023; 66(5):884-896.

PMID: 36884057 PMC: 10036285. DOI: 10.1007/s00125-023-05882-y.

The need and benefit of immune monitoring to define patient and disease heterogeneity, mechanisms of therapeutic action and efficacy of intervention therapy for precision medicine in type 1 diabetes.

Roep B Front Immunol. 2023; 14:1112858.

PMID: 36733487 PMC: 9887285. DOI: 10.3389/fimmu.2023.1112858.

Epitope-based precision immunotherapy of Type 1 diabetes.

Firdessa Fite R, Bechi Genzano C, Mallone R, Creusot R Hum Vaccin Immunother. 2023; 19(1):2154098.

PMID: 36656048 PMC: 9980607. DOI: 10.1080/21645515.2022.2154098.

References

Dogra R, Vaidyanathan P, Prabakar K, Marshall K, Hutton J, Pugliese A . Alternative splicing of G6PC2, the gene coding for the islet-specific glucose-6-phosphatase catalytic subunit-related protein (IGRP), results in differential expression in human thymus and spleen compared with pancreas. Diabetologia. 2006; 49(5):953-7. DOI: 10.1007/s00125-006-0185-8. View

Mallone R, Martinuzzi E, Blancou P, Novelli G, Afonso G, Dolz M . CD8+ T-cell responses identify beta-cell autoimmunity in human type 1 diabetes. Diabetes. 2007; 56(3):613-21. DOI: 10.2337/db06-1419. View

Gardner J, DeVoss J, Friedman R, Wong D, Tan Y, Zhou X . Deletional tolerance mediated by extrathymic Aire-expressing cells. Science. 2008; 321(5890):843-7. PMC: 2532844. DOI: 10.1126/science.1159407. View

James E, Kwok W . Low-affinity major histocompatibility complex-binding peptides in type 1 diabetes. Diabetes. 2008; 57(7):1788-9. PMC: 2453629. DOI: 10.2337/db08-0530. View

Gorus F, Goubert P, Semakula C, Vandewalle C, De Schepper J, Scheen A . IA-2-autoantibodies complement GAD65-autoantibodies in new-onset IDDM patients and help predict impending diabetes in their siblings. The Belgian Diabetes Registry. Diabetologia. 1997; 40(1):95-9. DOI: 10.1007/s001250050648. View

Bulek A, Cole D, Skowera A, Dolton G, Gras S, Madura F . Structural basis for the killing of human beta cells by CD8(+) T cells in type 1 diabetes. Nat Immunol. 2012; 13(3):283-9. PMC: 3378510. DOI: 10.1038/ni.2206. View

Unger W, Velthuis J, Abreu J, Laban S, Quinten E, Kester M . Discovery of low-affinity preproinsulin epitopes and detection of autoreactive CD8 T-cells using combinatorial MHC multimers. J Autoimmun. 2011; 37(3):151-9. DOI: 10.1016/j.jaut.2011.05.012. View

Yang J, Danke N, Berger D, Reichstetter S, Reijonen H, Greenbaum C . Islet-specific glucose-6-phosphatase catalytic subunit-related protein-reactive CD4+ T cells in human subjects. J Immunol. 2006; 176(5):2781-9. DOI: 10.4049/jimmunol.176.5.2781. View

Krishnamurthy B, Dudek N, McKenzie M, Purcell A, Brooks A, Gellert S . Responses against islet antigens in NOD mice are prevented by tolerance to proinsulin but not IGRP. J Clin Invest. 2006; 116(12):3258-65. PMC: 1679712. DOI: 10.1172/JCI29602. View

10.

Lieberman S, Evans A, Han B, Takaki T, Vinnitskaya Y, Caldwell J . Identification of the beta cell antigen targeted by a prevalent population of pathogenic CD8+ T cells in autoimmune diabetes. Proc Natl Acad Sci U S A. 2003; 100(14):8384-8. PMC: 166238. DOI: 10.1073/pnas.0932778100. View

11.

Klein L, Klugmann M, Nave K, Tuohy V, Kyewski B . Shaping of the autoreactive T-cell repertoire by a splice variant of self protein expressed in thymic epithelial cells. Nat Med. 1999; 6(1):56-61. DOI: 10.1038/71540. View

12.

Hadrup S, Bakker A, Shu C, Andersen R, van Veluw J, Hombrink P . Parallel detection of antigen-specific T-cell responses by multidimensional encoding of MHC multimers. Nat Methods. 2009; 6(7):520-6. DOI: 10.1038/nmeth.1345. View

13.

Zehn D, Bevan M . T cells with low avidity for a tissue-restricted antigen routinely evade central and peripheral tolerance and cause autoimmunity. Immunity. 2006; 25(2):261-70. PMC: 2774714. DOI: 10.1016/j.immuni.2006.06.009. View

14.

Velthuis J, Unger W, Abreu J, Duinkerken G, Franken K, Peakman M . Simultaneous detection of circulating autoreactive CD8+ T-cells specific for different islet cell-associated epitopes using combinatorial MHC multimers. Diabetes. 2010; 59(7):1721-30. PMC: 2889772. DOI: 10.2337/db09-1486. View

15.

Palmer E . Negative selection--clearing out the bad apples from the T-cell repertoire. Nat Rev Immunol. 2003; 3(5):383-91. DOI: 10.1038/nri1085. View

16.

Pobezinsky L, Angelov G, Tai X, Jeurling S, Van Laethem F, Feigenbaum L . Clonal deletion and the fate of autoreactive thymocytes that survive negative selection. Nat Immunol. 2012; 13(6):569-78. PMC: 3362677. DOI: 10.1038/ni.2292. View

17.

Mueller D . Mechanisms maintaining peripheral tolerance. Nat Immunol. 2009; 11(1):21-7. DOI: 10.1038/ni.1817. View

18.

Tan T, Geluk A, Toebes M, Ottenhoff T, Drijfhout J . A novel, highly efficient peptide-HLA class I binding assay using unfolded heavy chain molecules: identification of HIV-1 derived peptides that bind to HLA-A*0201 and HLA-A*0301. J Immunol Methods. 1997; 205(2):201-9. DOI: 10.1016/s0022-1759(97)00086-0. View

19.

Wong C, Li L, Frelinger J, Tisch R . Early autoimmune destruction of islet grafts is associated with a restricted repertoire of IGRP-specific CD8+ T cells in diabetic nonobese diabetic mice. J Immunol. 2006; 176(3):1637-44. DOI: 10.4049/jimmunol.176.3.1637. View

20.

Weerkamp F, de Haas E, Naber B, Comans-Bitter W, Bogers A, van Dongen J . Age-related changes in the cellular composition of the thymus in children. J Allergy Clin Immunol. 2005; 115(4):834-40. DOI: 10.1016/j.jaci.2004.10.031. View