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Williams MD, Bacher R, Perry DJ, Grace CR, McGrail KM, Posgai AL, Muir A, Chamala S, Haller MJ, Schatz DA, Brusko TM, Atkinson MA, Wasserfall CH. Genetic Composition and Autoantibody Titers Model the Probability of Detecting C-Peptide Following Type 1 Diabetes Diagnosis. Diabetes 2021; 70:932-943. [PMID: 33419759 PMCID: PMC7980194 DOI: 10.2337/db20-0937] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Accepted: 01/01/2021] [Indexed: 12/15/2022]
Abstract
We and others previously demonstrated that a type 1 diabetes genetic risk score (GRS) improves the ability to predict disease progression and onset in at-risk subjects with islet autoantibodies. Here, we hypothesized that GRS and islet autoantibodies, combined with age at onset and disease duration, could serve as markers of residual β-cell function following type 1 diabetes diagnosis. Generalized estimating equations were used to investigate whether GRS along with insulinoma-associated protein-2 autoantibody (IA-2A), zinc transporter 8 autoantibody (ZnT8A), and GAD autoantibody (GADA) titers were predictive of C-peptide detection in a largely cross-sectional cohort of 401 subjects with type 1 diabetes (median duration 4.5 years [range 0-60]). Indeed, a combined model with incorporation of disease duration, age at onset, GRS, and titers of IA-2A, ZnT8A, and GADA provided superior capacity to predict C-peptide detection (quasi-likelihood information criterion [QIC] = 334.6) compared with the capacity of disease duration, age at onset, and GRS as the sole parameters (QIC = 359.2). These findings support the need for longitudinal validation of our combinatorial model. The ability to project the rate and extent of decline in residual C-peptide production for individuals with type 1 diabetes could critically inform enrollment and benchmarking for clinical trials where investigators are seeking to preserve or restore endogenous β-cell function.
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Affiliation(s)
- MacKenzie D Williams
- Department of Pathology, Immunology and Laboratory Medicine, Diabetes Institute, College of Medicine, University of Florida, Gainesville, FL
| | - Rhonda Bacher
- Department of Biostatistics, College of Public Health and Health Professions, and College of Medicine, University of Florida, Gainesville, FL
| | - Daniel J Perry
- Department of Pathology, Immunology and Laboratory Medicine, Diabetes Institute, College of Medicine, University of Florida, Gainesville, FL
| | - C Ramsey Grace
- Department of Pathology, Immunology and Laboratory Medicine, Diabetes Institute, College of Medicine, University of Florida, Gainesville, FL
| | - Kieran M McGrail
- Department of Pathology, Immunology and Laboratory Medicine, Diabetes Institute, College of Medicine, University of Florida, Gainesville, FL
| | - Amanda L Posgai
- Department of Pathology, Immunology and Laboratory Medicine, Diabetes Institute, College of Medicine, University of Florida, Gainesville, FL
| | - Andrew Muir
- Department of Pediatrics, Emory University, Atlanta, GA
| | - Srikar Chamala
- Department of Pathology, Immunology and Laboratory Medicine, Diabetes Institute, College of Medicine, University of Florida, Gainesville, FL
| | - Michael J Haller
- Department of Pediatrics, Diabetes Institute, College of Medicine, University of Florida, Gainesville, FL
| | - Desmond A Schatz
- Department of Pediatrics, Diabetes Institute, College of Medicine, University of Florida, Gainesville, FL
| | - Todd M Brusko
- Department of Pathology, Immunology and Laboratory Medicine, Diabetes Institute, College of Medicine, University of Florida, Gainesville, FL
- Department of Pediatrics, Diabetes Institute, College of Medicine, University of Florida, Gainesville, FL
| | - Mark A Atkinson
- Department of Pathology, Immunology and Laboratory Medicine, Diabetes Institute, College of Medicine, University of Florida, Gainesville, FL
- Department of Pediatrics, Diabetes Institute, College of Medicine, University of Florida, Gainesville, FL
| | - Clive H Wasserfall
- Department of Pathology, Immunology and Laboratory Medicine, Diabetes Institute, College of Medicine, University of Florida, Gainesville, FL
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Ziegler AG, Bonifacio E. Why is the presence of autoantibodies against GAD associated with a relatively slow progression to clinical diabetes? Diabetologia 2020; 63:1665-1666. [PMID: 32451571 PMCID: PMC7351841 DOI: 10.1007/s00125-020-05175-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Accepted: 04/10/2020] [Indexed: 12/15/2022]
Affiliation(s)
- Anette-Gabriele Ziegler
- Institute of Diabetes Research, Helmholtz Zentrum München, German Research Center for Environmental Health, Munich-Neuherberg, Germany
- Forschergruppe Diabetes, Technical University Munich, at Klinikum rechts der Isar, Munich, Germany
| | - Ezio Bonifacio
- Center for Regenerative Therapies Dresden, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, Fetcherstrasse 105, 01307, Dresden, Germany.
- Paul Langerhans Institute Dresden of the Helmholtz Center Munich at University Hospital Carl Gustav Carus and Faculty of Medicine, Technische Universität, Dresden, Germany.
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Walther D, Eugster A, Jergens S, Gavrisan A, Weinzierl C, Telieps T, Winkler C, Ziegler AG, Bonifacio E. Tetraspanin 7 autoantibodies in type 1 diabetes. Diabetologia 2016; 59:1973-6. [PMID: 27221092 DOI: 10.1007/s00125-016-3997-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Accepted: 05/04/2016] [Indexed: 12/23/2022]
Abstract
AIMS/HYPOTHESIS Autoantibodies to pancreatic beta cell proteins are markers of asymptomatic type 1 diabetes. The aim was to determine whether autoantibodies to the beta cell protein tetraspanin 7 would improve the ability to identify autoimmunity against pancreatic beta cells. METHODS Full length and external domain fragments of tetraspanin 7 were expressed as luciferase-tagged fusion proteins and used in immunoprecipitation assays to measure autoantibodies in samples from 363 patients with type 1 diabetes at onset of disease, 503 beta cell autoantibody negative first-degree relatives of patients, and 212 relatives with autoantibodies to insulin, glutamic acid decarboxylase, insulinoma antigen 2 or zinc transporter 8. RESULTS Antibody binding was observed against the full length and external domains of tetraspanin 7, and was strongest against the full length protein. Autoantibodies that could be inhibited by untagged tetraspanin 7 were detected in 5 (1%) of 503 autoantibody negative relatives, 3 (3.2%) of 94 autoantibody negative patients, 95 (35.3%) of 269 autoantibody positive patients, 1 (1%) of 98 single autoantibody positive relatives and 25 (21.9%) of 114 multiple autoantibody positive relatives. Progression to diabetes did not differ between multiple autoantibody positive relatives with and without tetraspanin 7 autoantibodies. CONCLUSIONS/INTERPRETATION Tetraspanin 7 is an autoantigen in type 1 diabetes. Tetraspanin 7 autoantibodies are a marker of type 1 diabetes, but provide minor additional value to existing autoantibodies in identifying beta cell autoimmunity.
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Affiliation(s)
- Denise Walther
- DFG Research Center for Regenerative Therapies Dresden, Faculty of Medicine, Technische Universität Dresden, Fetscherstrasse 105, 01307, Dresden, Germany
| | - Anne Eugster
- DFG Research Center for Regenerative Therapies Dresden, Faculty of Medicine, Technische Universität Dresden, Fetscherstrasse 105, 01307, Dresden, Germany
| | - Sibille Jergens
- Institute of Diabetes Research, Helmholtz Zentrum München, and Forschergruppe Diabetes, Klinikum rechts der Isar, Technische Universität München, Neuherberg, Germany
| | | | - Christina Weinzierl
- Institute of Diabetes and Obesity, Helmholtz Zentrum München, Neuherberg, Germany
| | - Tanja Telieps
- Institute of Diabetes and Obesity, Helmholtz Zentrum München, Neuherberg, Germany
| | - Christiane Winkler
- Institute of Diabetes Research, Helmholtz Zentrum München, and Forschergruppe Diabetes, Klinikum rechts der Isar, Technische Universität München, Neuherberg, Germany
| | - Anette G Ziegler
- Institute of Diabetes Research, Helmholtz Zentrum München, and Forschergruppe Diabetes, Klinikum rechts der Isar, Technische Universität München, Neuherberg, Germany
- Forschergruppe Diabetes e.V., Neuherberg, Germany
| | - Ezio Bonifacio
- DFG Research Center for Regenerative Therapies Dresden, Faculty of Medicine, Technische Universität Dresden, Fetscherstrasse 105, 01307, Dresden, Germany.
- Paul Langerhans Institute Dresden, German Center for Diabetes Research (DZD), Technische Universität Dresden, Dresden, Germany.
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Elvers KT, Williams AJK. Molecular Methods and Protein Synthesis for Definition of Autoantibody Epitopes. Methods Mol Biol 2016; 1433:179-207. [PMID: 27032951 DOI: 10.1007/7651_2016_339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
Abstract
Epitope mapping is the process of experimentally identifying the binding sites, or "epitopes," of antibodies on their target antigens. Understanding the antibody-epitope interaction provides a basis for the rational design of potential preventative vaccines. Islet autoantibodies are currently the best available biomarkers for predicting future type 1 diabetes. These include autoantibodies to the islet beta cell proteins, insulin and the tyrosine phosphatase islet antigen-2 (IA-2) which selectively bind to a small number of dominant epitopes associated with increased risk of disease progression. The major epitope regions of insulin and IA-2 autoantibodies have been identified, but need to be mapped more precisely. In order to characterize these epitopes more accurately, this article describes the methods of cloning and mutagenesis of insulin and IA-2 and subsequent purification of the proteins that can be tested in displacement analysis and used to monitor immune responses, in vivo, to native and mutated proteins in a humanized mouse model carrying the high-risk HLA class II susceptibility haplotype DRB1*04-DQ8.
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Affiliation(s)
- Karen T Elvers
- Diabetes and Metabolism Unit, School of Clinical Sciences, Southmead Hospital, University of Bristol, Bristol, UK.
| | - Alistair J K Williams
- Diabetes and Metabolism Unit, School of Clinical Sciences, Southmead Hospital, University of Bristol, Bristol, UK
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Xu H, Abuhatzira L, Carmona GN, Vadrevu S, Satin LS, Notkins AL. The Ia-2β intronic miRNA, miR-153, is a negative regulator of insulin and dopamine secretion through its effect on the Cacna1c gene in mice. Diabetologia 2015; 58:2298-306. [PMID: 26141787 PMCID: PMC6754265 DOI: 10.1007/s00125-015-3683-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Accepted: 06/11/2015] [Indexed: 12/23/2022]
Abstract
AIMS/HYPOTHESIS miR-153 is an intronic miRNA embedded in the genes that encode IA-2 (also known as PTPRN) and IA-2β (also known as PTPRN2). Islet antigen (IA)-2 and IA-2β are major autoantigens in type 1 diabetes and are important transmembrane proteins in dense core and synaptic vesicles. miR-153 and its host genes are co-regulated in pancreas and brain. The present experiments were initiated to decipher the regulatory network between miR-153 and its host gene Ia-2β (also known as Ptprn2). METHODS Insulin secretion was determined by ELISA. Identification of miRNA targets was assessed using luciferase assays and by quantitative real-time PCR and western blots in vitro and in vivo. Target protector was also employed to evaluate miRNA target function. RESULTS Functional studies revealed that miR-153 mimic suppresses both glucose- and potassium-induced insulin secretion (GSIS and PSIS, respectively), whereas miR-153 inhibitor enhances both GSIS and PSIS. A similar effect on dopamine secretion also was observed. Using miRNA target prediction software, we found that miR-153 is predicted to target the 3'UTR region of the calcium channel gene, Cacna1c. Further studies confirmed that Cacna1c mRNA and protein are downregulated by miR-153 mimics and upregulated by miR-153 inhibitors in insulin-secreting freshly isolated mouse islets, in the insulin-secreting mouse cell line MIN6 and in the dopamine-secreting cell line PC12. CONCLUSIONS/INTERPRETATION miR-153 is a negative regulator of both insulin and dopamine secretion through its effect on Cacna1c expression, which suggests that IA-2β and miR-153 have opposite functional effects on the secretory pathway.
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Affiliation(s)
- Huanyu Xu
- Experimental Medicine Section, Laboratory of Sensory Biology, National Institute of Dental and Craniofacial Research, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD, 20892, USA
| | - Liron Abuhatzira
- Experimental Medicine Section, Laboratory of Sensory Biology, National Institute of Dental and Craniofacial Research, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD, 20892, USA
| | - Gilberto N Carmona
- Experimental Medicine Section, Laboratory of Sensory Biology, National Institute of Dental and Craniofacial Research, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD, 20892, USA
| | - Suryakiran Vadrevu
- Brehm Diabetes Research Center, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Leslie S Satin
- Brehm Diabetes Research Center, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Abner L Notkins
- Experimental Medicine Section, Laboratory of Sensory Biology, National Institute of Dental and Craniofacial Research, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD, 20892, USA.
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Cai T, Hirai H, Xu H, Notkins AL. The minimal promoter region of the dense-core vesicle protein IA-2: transcriptional regulation by CREB. Acta Diabetol 2015; 52:573-80. [PMID: 25528004 PMCID: PMC5273861 DOI: 10.1007/s00592-014-0689-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Accepted: 11/20/2014] [Indexed: 11/29/2022]
Abstract
AIMS IA-2 is a transmembrane protein found in the dense-core vesicles (DCV) of neuroendocrine cells and one of the major autoantigens in type 1 diabetes. DCV are involved in the secretion of hormones (e.g., insulin) and neurotransmitters. Stimulation of pancreatic β cells with glucose upregulates the expression of IA-2 and an increase in IA-2 results in an increase in the number of DCV. Little is known, however, about the promoter region of IA-2 or the transcriptional factors that regulate the expression of this gene. METHODS In the present study, we constructed eight deletion fragments from the upstream region of the IA-2 transcription start site and linked them to a luciferase reporter. RESULTS By this approach, we have identified a short bp region (-216 to +115) that has strong promoter activity. We also identified a transcription factor, cAMP responsive element-binding protein (CREB), which binds to two CREB-related binding sites located in this region. The binding of CREB to these sites enhanced IA-2 transcription by more than fivefold. We confirmed these findings by site-directed mutagenesis, chromatin immunoprecipitation assays and RNAi inhibition. CONCLUSION Based on these findings, we conclude that the PKA pathway is a critical, but not the exclusive signaling pathway involved in IA-2 gene expression.
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Affiliation(s)
- Tao Cai
- Experimental Medicine Section, Laboratory of Sensory Biology, National Institute of Dental and Craniofacial Research (NIDCR), National Institutes of Health (NIH), B30/Rm106, Bethesda, MD, 20892, USA,
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Sorokin AV, Nair BC, Wei Y, Aziz KE, Evdokimova V, Hung MC, Chen J. Aberrant Expression of proPTPRN2 in Cancer Cells Confers Resistance to Apoptosis. Cancer Res 2015; 75:1846-58. [PMID: 25877877 DOI: 10.1158/0008-5472.can-14-2718] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Accepted: 02/01/2015] [Indexed: 01/09/2023]
Abstract
The protein tyrosine phosphatase receptor PTPRN2 is expressed predominantly in endocrine and neuronal cells, where it functions in exocytosis. We found that its immature isoform proPTPRN2 is overexpressed in various cancers, including breast cancer. High proPTPRN2 expression was associated strongly with lymph node-positive breast cancer and poor clinical outcome. Loss of proPTPRN2 in breast cancer cells promoted apoptosis and blocked tumor formation in mice, whereas enforced expression of proPTPRN2 in nontransformed human mammary epithelial cells exerted a converse effect. Mechanistic investigations suggested that ProPTPRN2 elicited these effects through direct interaction with TRAF2, a hub scaffold protein for multiple kinase cascades, including ones that activate NF-κB. Overall, our results suggest PTPRN2 as a novel candidate biomarker and therapeutic target in breast cancer.
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Affiliation(s)
- Alexey V Sorokin
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Binoj C Nair
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Yongkun Wei
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Kathryn E Aziz
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Valentina Evdokimova
- Department of Genomics, Ontario Institute for Cancer Research, Toronto, Ontario, Canada
| | - Mien-Chie Hung
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas. Center for Molecular Medicine and Graduate Institute of Cancer Biology, China Medical University, Taichung, Taiwan
| | - Junjie Chen
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas.
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Fernando R, Vonberg A, Atkins SJ, Pietropaolo S, Pietropaolo M, Smith TJ. Human fibrocytes express multiple antigens associated with autoimmune endocrine diseases. J Clin Endocrinol Metab 2014; 99:E796-803. [PMID: 24517144 PMCID: PMC4010713 DOI: 10.1210/jc.2013-3072] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Factors common to multiple autoimmune diseases have been sought vigorously. Graves' disease (GD) and type 1 diabetes mellitus (T1DM) involve end-organ remodeling. Fibrocytes participate in inflammatory diseases and were recently shown to express thyroid-specific proteins such as the thyrotropin receptor and thyroglobulin. OBJECTIVE The objective of the study was to determine whether a broader repertoire of autoantigen expression, such as proteins associated with T1DM, can be ascribed to fibrocytes. DESIGN, SETTING, AND PARTICIPANTS Fibrocytes and fibroblasts were collected and analyzed from healthy individuals and those with autoimmune diseases in an academic clinical practice. MAIN OUTCOME MEASURES Real-time PCR, Western blot analysis, gene promoter analysis, cell transfections, and flow cytometric cell sorting were performed. RESULTS Islet cell antigen ICA512 (IA-2) and islet cell autoantigen of 69 kDa (ICA69), two islet-specific proteins implicated in T1DM, are expressed by fibrocytes from healthy donors and those with T1DM, GD, and multiple sclerosis. Both transcripts are detected by PCR, the proteins are resolved on Western blots, and both gene promoters are active in fibrocytes. Levels of ICA69 are substantially higher than those of IA-2 in fibrocytes. ICA69 localizes to CD34(+) GD orbital fibroblasts putatively derived from fibrocytes, whereas higher levels of IA-2 are found in CD34(-) fibroblasts. CONCLUSIONS In addition to autoantigens implicated in thyroid autoimmunity, fibrocytes and derivative fibroblasts express multiple autoantigens associated with T1DM. This expression results from active gene promoters and abundant steady-state mRNA encoding ICA69 and IA-2. These latest findings demonstrate that fibrocytes express antigens relevant to multiple forms of endocrine autoimmunity. They suggest the potential for these cells playing a direct role in immune reactivity directed at the thyroid and pancreatic islets.
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Affiliation(s)
- Roshini Fernando
- Department of Ophthalmology and Visual Sciences (R.F., S.J.A., T.J.S.), Kellogg Eye Center and Division of Metabolism, Endocrinology, and Diabetes (A.V., S.P., M.P., T.J.S.), Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan 48105
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Mandemakers W, Abuhatzira L, Xu H, Caromile LA, Hébert SS, Snellinx A, Morais VA, Matta S, Cai T, Notkins AL, De Strooper B. Co-regulation of intragenic microRNA miR-153 and its host gene Ia-2 β: identification of miR-153 target genes with functions related to IA-2β in pancreas and brain. Diabetologia 2013; 56:1547-56. [PMID: 23595248 PMCID: PMC3671108 DOI: 10.1007/s00125-013-2901-5] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2013] [Accepted: 02/26/2013] [Indexed: 01/01/2023]
Abstract
AIMS/HYPOTHESIS We analysed the genomic organisation of miR-153, a microRNA embedded in genes that encode two of the major type 1 diabetes autoantigens, islet-associated protein (IA)-2 and IA-2β. We also identified miR-153 target genes that correlated with IA-2β localisation and function. METHODS A bioinformatics approach was used to identify miR-153's genomic organisation. To analyse the co-regulation of miR-153 and IA-2β, quantitative PCR analysis of miR-153 and Ia-2β (also known as Ptprn2) was performed after a glucose stimulation assay in MIN6B cells and isolated murine pancreatic islets, and also in wild-type Ia-2 (also known as Ptprn), Ia-2β single knockout and Ia-2/Ia-2β double knockout mouse brain and pancreatic islets. Bioinformatics identification of miR-153 target genes and validation via luciferase reporter assays, western blotting and quantitative PCR were also carried out. RESULTS Two copies of miR-153, miR-153-1 and miR-153-2, are localised in intron 19 of Ia-2 and Ia-2β, respectively. In rodents, only miR-153-2 is conserved. We demonstrated that expression of miR-153-2 and Ia-2β in rodents is partially co-regulated as demonstrated by a strong reduction of miR-153 expression levels in Ia-2β knockout and Ia-2/Ia-2β double knockout mice. miR-153 levels were unaffected in Ia-2 knockout mice. In addition, glucose stimulation, which increases Ia-2 and Ia-2β expression, also significantly increased expression of miR-153. Several predicted targets of miR-153 were reduced after glucose stimulation in vitro, correlating with the increase in miR-153 levels. CONCLUSIONS/INTERPRETATION This study suggests the involvement of miR-153, IA-2β and miR-153 target genes in a regulatory network, which is potentially relevant to insulin and neurotransmitter release.
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Affiliation(s)
- W. Mandemakers
- VIB Center for the Biology of Disease, Gasthuisberg O&N4, Herestraat 49-bus 602, 3000 Leuven, Belgium
- Center for Human Genetics, LIND and Universitaire Ziekenhuizen, KULeuven, Leuven, Belgium
| | - L. Abuhatzira
- Experimental Medicine Section, Oral Infection and Immunity Branch, National Institute of Dental and Craniofacial Research, National Institute of Health, Bethesda, MD USA
| | - H. Xu
- Experimental Medicine Section, Oral Infection and Immunity Branch, National Institute of Dental and Craniofacial Research, National Institute of Health, Bethesda, MD USA
| | - L. A. Caromile
- Experimental Medicine Section, Oral Infection and Immunity Branch, National Institute of Dental and Craniofacial Research, National Institute of Health, Bethesda, MD USA
| | - S. S. Hébert
- VIB Center for the Biology of Disease, Gasthuisberg O&N4, Herestraat 49-bus 602, 3000 Leuven, Belgium
- Center for Human Genetics, LIND and Universitaire Ziekenhuizen, KULeuven, Leuven, Belgium
- Present Address: Neurosciences, Centre de Recherche du CHUQ (CHUL), RC-9800, 2705 boul. Laurier, Québec, QC Canada
| | - A. Snellinx
- VIB Center for the Biology of Disease, Gasthuisberg O&N4, Herestraat 49-bus 602, 3000 Leuven, Belgium
- Center for Human Genetics, LIND and Universitaire Ziekenhuizen, KULeuven, Leuven, Belgium
| | - V. A. Morais
- VIB Center for the Biology of Disease, Gasthuisberg O&N4, Herestraat 49-bus 602, 3000 Leuven, Belgium
- Center for Human Genetics, LIND and Universitaire Ziekenhuizen, KULeuven, Leuven, Belgium
| | - S. Matta
- VIB Center for the Biology of Disease, Gasthuisberg O&N4, Herestraat 49-bus 602, 3000 Leuven, Belgium
- Center for Human Genetics, LIND and Universitaire Ziekenhuizen, KULeuven, Leuven, Belgium
| | - T. Cai
- Experimental Medicine Section, Oral Infection and Immunity Branch, National Institute of Dental and Craniofacial Research, National Institute of Health, Bethesda, MD USA
| | - A. L. Notkins
- Experimental Medicine Section, Oral Infection and Immunity Branch, National Institute of Dental and Craniofacial Research, National Institute of Health, Bethesda, MD USA
| | - B. De Strooper
- VIB Center for the Biology of Disease, Gasthuisberg O&N4, Herestraat 49-bus 602, 3000 Leuven, Belgium
- Center for Human Genetics, LIND and Universitaire Ziekenhuizen, KULeuven, Leuven, Belgium
- Center for Human Genetics-CB4, VIB Center for the Biology of Disease–VIB11, Gasthuisberg O&N4, Herestraat 49-bus 602, 3000 Leuven, Belgium
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Punia S, Rumery KK, Yu EA, Lambert CM, Notkins AL, Weaver DR. Disruption of gene expression rhythms in mice lacking secretory vesicle proteins IA-2 and IA-2β. Am J Physiol Endocrinol Metab 2012; 303:E762-76. [PMID: 22785238 PMCID: PMC3468428 DOI: 10.1152/ajpendo.00513.2011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Insulinoma-associated protein (IA)-2 and IA-2β are transmembrane proteins involved in neurotransmitter secretion. Mice with targeted disruption of both IA-2 and IA-2β (double-knockout, or DKO mice) have numerous endocrine and physiological disruptions, including disruption of circadian and diurnal rhythms. In the present study, we have assessed the impact of disruption of IA-2 and IA-2β on molecular rhythms in the brain and peripheral oscillators. We used in situ hybridization to assess molecular rhythms in the hypothalamic suprachiasmatic nuclei (SCN) of wild-type (WT) and DKO mice. The results indicate significant disruption of molecular rhythmicity in the SCN, which serves as the central pacemaker regulating circadian behavior. We also used quantitative PCR to assess gene expression rhythms in peripheral tissues of DKO, single-knockout, and WT mice. The results indicate significant attenuation of gene expression rhythms in several peripheral tissues of DKO mice but not in either single knockout. To distinguish whether this reduction in rhythmicity reflects defective oscillatory function in peripheral tissues or lack of entrainment of peripheral tissues, animals were injected with dexamethasone daily for 15 days, and then molecular rhythms were assessed throughout the day after discontinuation of injections. Dexamethasone injections improved gene expression rhythms in liver and heart of DKO mice. These results are consistent with the hypothesis that peripheral tissues of DKO mice have a functioning circadian clockwork, but rhythmicity is greatly reduced in the absence of robust, rhythmic physiological signals originating from the SCN. Thus, IA-2 and IA-2β play an important role in the regulation of circadian rhythms, likely through their participation in neurochemical communication among SCN neurons.
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Affiliation(s)
- Sohan Punia
- Experimental Medicine Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA
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Wang Y, Nishi M, Doi A, Shono T, Furukawa Y, Shimada T, Furuta H, Sasaki H, Nanjo K. Ghrelin inhibits insulin secretion through the AMPK-UCP2 pathway in beta cells. FEBS Lett 2010; 584:1503-8. [PMID: 20206170 DOI: 10.1016/j.febslet.2010.02.069] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2009] [Revised: 02/22/2010] [Accepted: 02/27/2010] [Indexed: 02/04/2023]
Abstract
Ghrelin inhibits insulin secretion partly via induction of IA-2beta. However, the orexigenic effect of ghrelin is mediated by the AMP-activated protein kinase (AMPK)-uncoupling protein 2 (UCP2) pathway. Here, we demonstrate that ghrelin's inhibitory effect on insulin secretion also occurs through the AMPK-UCP2 pathway. Ghrelin increased AMPK phosphorylation and UCP2 mRNA expression in MIN6 insulinoma cells. Overexpression or downregulation of UCP2 attenuated or enhanced insulin secretion, respectively. Furthermore, AMPK activator had a similar effect to ghrelin on UCP2 and insulin secretion in MIN6 cells. In conclusion, ghrelin's inhibitory effect on insulin secretion is partly mediated by the AMPK-UCP2 pathway, which is independent of the IA-2beta pathway.
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Affiliation(s)
- Ying Wang
- The First Department of Medicine, Wakayama Medical University, Wakayama, Japan
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12
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Takeyama N, Ano Y, Wu G, Kubota N, Saeki K, Sakudo A, Momotani E, Sugiura K, Yukawa M, Onodera T. Localization of insulinoma associated protein 2, IA-2 in mouse neuroendocrine tissues using two novel monoclonal antibodies. Life Sci 2009; 84:678-87. [PMID: 19233214 DOI: 10.1016/j.lfs.2009.02.012] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2008] [Revised: 02/02/2009] [Accepted: 02/10/2009] [Indexed: 11/19/2022]
Abstract
AIMS Insulinoma-associated protein 2 (IA-2) is a member of the protein tyrosine phosphatase family that is localized on the insulin granule membrane. IA-2 is also well known as one of the major autoantigens in Type 1 diabetes mellitus. IA-2 gene deficient mice were recently established and showed abnormalities in insulin secretion. Thus, detailed localization of IA-2 was studied using wild-type and IA-2 gene deficient mice. MAIN METHODS To localize IA-2 expression in mouse neuroendocrine tissues, monoclonal antibodies were generated against IA-2 and western blot and immunohistochemical analyses were carried out in IA-2(+/+) mice. IA-2(-/-) mice served as a negative control. KEY FINDINGS Western blot analysis revealed that the 65 kDa form of IA-2 was observed in the cerebrum, cerebellum, medulla oblongata, pancreas, adrenal gland, pituitary gland, muscular layers of the stomach, small intestine, and colon. By immunohistochemical analysis, IA-2 was produced in endocrine cells in pancreatic islets, adrenal medullary cells, thyroid C-cells, Kulchitsky cells, and anterior, intermediate, and posterior pituitary cells. In addition, IA-2 was found in somatostatin-producing D-cells and other small populations of cells were scattered in the gastric corpus. IA-2 expression in neurites was confirmed by the immunostaining of IA-2 using primary cultured neurons from the small intestine and nerve growth factor (NGF)-differentiated PC12 cells. SIGNIFICANCE The IA-2 distribution in peripheral neurons appeared more intensely in neurites rather than in the cell bodies.
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Affiliation(s)
- Natsumi Takeyama
- Department of Molecular Immunology, School of Agricultural and Life Sciences, University of Tokyo, Bunkyo-ku, Tokyo, Japan
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13
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Törn C, Mueller PW, Schlosser M, Bonifacio E, Bingley PJ. Diabetes Antibody Standardization Program: evaluation of assays for autoantibodies to glutamic acid decarboxylase and islet antigen-2. Diabetologia 2008; 51:846-52. [PMID: 18373080 DOI: 10.1007/s00125-008-0967-2] [Citation(s) in RCA: 165] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2007] [Accepted: 01/14/2008] [Indexed: 02/07/2023]
Abstract
AIMS/HYPOTHESIS Islet autoantibodies are important in diabetes classification and risk assessment, and as endpoints in observational studies. The Diabetes Autoantibody Standardization Program (DASP) aims to improve and standardise measurement of autoantibodies associated with type 1 diabetes. We report results for glutamic acid decarboxylase autoantibodies (GADA) and islet antigen-2 autoantibodies (IA-2A) from three DASP workshops (2002--2005). METHODS Up to 60 laboratories in 18 countries participated in each workshop. Participants received coded serum aliquots from 50 patients with newly diagnosed type 1 diabetes (median age 18 years, range 9-35 years) and 100 blood donor controls. Results were analysed using receiver operator characteristic (ROC) curves with sensitivity adjusted to 95% specificity in workshop controls. RESULTS GADA assays performed well in all three workshops (median area under the ROC curve [AUC] 0.94; interquartile range 0.91-0.95) and performance was similar to DASP 2000. Performance of IA-2A assays improved over the workshop programme. Median AUC was 0.81 (interquartile range 0.79-0.83) in DASP 2002, 0.82 (interquartile range 0.78-0.84) in 2003, and 0.85 (interquartile range 0.82-0.87) in 2005 (p < 0.0001). Performance of GADA ELISA improved between 2002 and 2005, and, in DASP 2005, achieved higher median AUC and adjusted sensitivity than RIA. IA-2A ELISA improved and, in DASP 2005, achieved AUCs equivalent to in-house RIA. Assays using IA-2ic or full length IA-2 clones were more sensitive than those using IA-2bdc, with higher AUC (p = 0.004). CONCLUSIONS/INTERPRETATION GADA and IA-2A assays perform well in discriminating health and disease. The workshop format highlights systematic differences related to assay method and allows full evaluation of novel methods. The programme of autoantibody workshops in type 1 diabetes provides a model for other autoimmune diseases.
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Affiliation(s)
- C Törn
- Unit for Diabetes and Coeliac Disease, Institution of Clinical Sciences, Clinical Research Centre, University Hospital MAS, Malmö, Sweden
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14
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Henquin JC, Nenquin M, Szollosi A, Kubosaki A, Notkins AL. Insulin secretion in islets from mice with a double knockout for the dense core vesicle proteins islet antigen-2 (IA-2) and IA-2beta. J Endocrinol 2008; 196:573-81. [PMID: 18310453 DOI: 10.1677/joe-07-0496] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Islet antigen-2 (IA-2 or ICA 512) and IA-2beta (or phogrin) are major autoantigens in type 1 diabetes. They are located in dense core secretory vesicles including insulin granules, but their role in beta-cell function is unclear. Targeted disruption of either IA-2 or IA-2beta, or both, impaired glucose tolerance, an effect attributed to diminution of insulin secretion. In this study, we therefore characterized the dynamic changes in cytosolic Ca2+([Ca2+](c)) and insulin secretion in islets from IA-2/IA-2beta double knockout (KO) mice. High glucose (15 mM) induced biphasic insulin secretion in IA-2/IA-2beta KO islets, with a similar first phase and smaller second phase compared with controls. Since the insulin content of IA-2/IA-2beta KO islets was approximately 45% less than that of controls, fractional insulin secretion (relative to content) was thus increased during first phase and unaffected during second phase. This peculiar response occurred in spite of a slightly smaller rise in [Ca2+](c), could not be attributed to an alteration of glucose metabolism (NADPH fluorescence) and also was observed with tolbutamide. The dual control of insulin secretion via the K(ATP) channel-dependent triggering pathway and K(ATP) channel-independent amplifying pathway was unaltered in IA-2/IA-2beta KO islets, and so were the potentiations by acetylcholine or cAMP (forskolin). Intriguingly, amino acids, in particular the cationic arginine and lysine, induced larger fractional insulin secretion in IA-2/IA-2beta KO than control islets. In conclusion, IA-2 and IA-2beta are dispensable for exocytosis of insulin granules, but are probably more important for cargo loading and/or stability of dense core vesicles.
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Affiliation(s)
- Jean-Claude Henquin
- Unit of Endocrinology and Metabolism, Faculty of Medicine, University of Louvain, UCL 55.30, Avenue Hippocrate 55, B-1200 Brussels, Belgium
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15
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Zhang G, Hirai H, Cai T, Miura J, Yu P, Huang H, Schiller MR, Swaim WD, Leapman RD, Notkins AL. RESP18, a homolog of the luminal domain IA-2, is found in dense core vesicles in pancreatic islet cells and is induced by high glucose. J Endocrinol 2007; 195:313-21. [PMID: 17951542 DOI: 10.1677/joe-07-0252] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The regulated endocrine-specific protein, RESP18, first found in the rat pituitary, was thought to be regulated by dopaminergic drugs. Bioinformatics studies showed that RESP18 shares sequence homology with the luminal region of IA-2, a dense core vesicle (DCV) transmembrane protein involved in insulin secretion. The present study was initiated to examine the genomic structure and subcellular localization of RESP18 and the effect of glucose on its expression. Human RESP18 was isolated from a pancreas cDNA library and its subcellular localization was determined by immunoelectron microscopy. MIN6 cells and mouse islets were used to study the effect of glucose on RESP18 expression. Bioinformatics analysis revealed that RESP18 and IA-2 are tandemly arranged within a 45 kb region on human chromosome 2 and share common intron-exon boundaries. By confocal microscopy, RESP18 was found in alpha, beta and delta cells in the pancreatic islets. Electron microscopy revealed that RESP18 is present in the lumen of DCVs. The expression of RESP18 in beta cells is markedly increased following exposure to high glucose and also elevated in the islets of diabetic, but not non-diabetic, NOD mice. We conclude that RESP18 is a luminal protein of DCVs and its expression is regulated by exposure to glucose.
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MESH Headings
- Animals
- Cell Line, Tumor
- Chromosome Mapping
- Chromosomes, Human, Pair 2
- Computational Biology
- Diabetes Mellitus, Type 1/metabolism
- Dose-Response Relationship, Drug
- Evolution, Molecular
- Genome, Human
- Glucose/administration & dosage
- Glucose/pharmacology
- Humans
- Insulinoma/metabolism
- Insulinoma/pathology
- Islets of Langerhans/cytology
- Islets of Langerhans/metabolism
- Mice
- Mice, Inbred NOD
- Microscopy, Confocal
- Microscopy, Electron
- Microscopy, Immunoelectron
- Nerve Tissue Proteins/genetics
- Nerve Tissue Proteins/metabolism
- Pancreatic Neoplasms/metabolism
- Pancreatic Neoplasms/pathology
- Receptor-Like Protein Tyrosine Phosphatases, Class 8/genetics
- Receptor-Like Protein Tyrosine Phosphatases, Class 8/metabolism
- Secretory Vesicles/metabolism
- Subcellular Fractions/metabolism
- Tissue Distribution
- Up-Regulation
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Affiliation(s)
- Guofeng Zhang
- Experimental Medicine Section, Oral Infection and Immunity Branch (OIIB), National Institute of Dental and Craniofacial Research (NIDCR), The National Institutes of Health (NIH), Bethesda, Maryland 20892, USA
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Abstract
Post-translational attachment of small ubiquitin-like modifier (SUMO), defined as SUMOylation, can affect the localization, interactions, stability and/or activity of substrate proteins, and thus can participate in a large variety of cellular processes. Most SUMO substrates are involved in transcriptional regulation. Hence, SUMOylation can either activate or, more commonly, repress gene transcription. The modulation of gene expression by SUMO through diverse mechanisms and specifically the recent findings concerning SUMOylation in pancreatic beta-cells are reviewed.
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Affiliation(s)
- A Ehninger
- Experimental Diabetology, Carl Gustav Carus Medical School, Dresden University of Technology, Dresden, Germany
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