Differential Expression of GAD65 and GAD67 in Human, Rat, and Mouse Pancreatic Islets

Kim, John; Richter, Wiltrud; Aanstoot, Henk‐Jan; Shi, Yuguang; Fu, Qin; Rajotte, Ray V.; Warnock, Garth L.; Baekkeskov, Steinunn

doi:10.2337/diab.42.12.1799

Cited by 139 publications

(125 citation statements)

References 25 publications

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“…It has been reported that the expression of GAD65 is under the detectable limit in mouse islets, whereas both rat and human islets express it at significantly higher Development of autoimmune diabetes in glutamic acid decarboxylase 65 (GAD65) 223 levels [8]. In our GAD65 −/− mice, the sudden death before the onset of diabetes might have been caused by severe dysfunction in the central nervous system, consistent with a previous report [9].…”

Section: Discussionsupporting

confidence: 80%

Development of autoimmune diabetes in glutamic acid decarboxylase 65 (GAD65) knockout NOD mice

et al. 2004

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Aims/hypothesis. Type 1 diabetes mellitus, a T-cellmediated autoimmune disease, results from the selective destruction of insulin-producing pancreatic beta cells. Autoantibodies against beta-cell components are used clinically as sensitive markers of this disease; however, their physiological role has not been clear. To investigate the role of glutamic acid decarboxylase 65 (GAD65) in the development of the Type 1 diabetes of non-obese diabetic (NOD) mice, we analysed and characterised NOD mice with targeted disruption of the GAD65 gene. Methods. GAD65-deficient mice were previously established. After backcrossing the knockout mutation onto the NOD genetic background for up to eight generations, female littermates of the three resulting genotypes were produced by intercrossing: GAD65 +/+ (n=23), GAD65 +/− (n=62), and GAD65 −/− (n=31).Results. The cumulative incidence of autoimmune diabetes showed no significant difference among the three groups in longitudinal studies using the KaplanMeier method. Islet morphology showed that the progression of islet infiltration did not differ significantly between the three groups. Conclusion/interpretation. The cumulative incidence of autoimmune diabetes was not influenced by the GAD65 deficiency. These data suggest that GAD65 is not a major regulatory target of beta-cell autoimmunity in NOD mice. [Diabetologia (2004) . It is, however, unclear whether the anti-GAD antibodies participate directly in betacell destruction or arise secondarily in response to the release of autoantigens from islets damaged by other components of the immune system. To investigate the role of GAD65 in the development of the autoimmune diabetes of NOD mice, we have generated GAD65 −/− NOD mice and analysed the onset and incidence of diabetes in these mice. Materials and methodsGeneration and genotyping of a GAD65 mutant mouse. We previously established 129/Ola-derived embryonic stem-cell clones carrying the GAD65 targeted mutation through homologous recombination [2]. GAD65 knockout embryonic stem cells were injected into C57BL/6 mouse blastocysts to make chimeras, and germ-line transmission was achieved. GAD65

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Section: Discussionsupporting

confidence: 80%

Development of autoimmune diabetes in glutamic acid decarboxylase 65 (GAD65) knockout NOD mice

et al. 2004

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“…Immunization of young NOD mice with human GAD65, the main immunogenic isoform of glutamate decarboxylase in human type 1 diabetes [24], can reduce the incidence of diabetes [7,8,[11][12][13][14]. Similar prevention was also obtained by immunization with the other isoform, GAD67 [10], which is predominant in mouse islets [25,26] and highly expressed [20] and modulable [22] in the NOD mouse. A limited number of peptides derived from the COOH terminus of the human GAD65 protein have been shown to stimulate in vitro the proliferation of splenic cells from young prediabetic NOD mice [7].…”

Section: Discussionmentioning

confidence: 95%

Immunization of non-obese diabetic (NOD) mice with glutamic acid decarboxylase-derived peptide 524–543 reduces cyclophosphamide-accelerated diabetes

Saı̈¹,

Rivereau²,

Granier

et al. 1996

Clinical and Experimental Immunology

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SUMMARYNOD mice constitute a model for studying the prevention of human autoimmune type 1 diabetes. Glutamic acid decarboxylase (GAD) could be a key antigen involved in this disease, and GAD65 peptide 524-543 has been implicated in early T cell response in young NOD mice. We performed two i.p. injections of GAD peptide 524-543 (100 ¹ g at each injection), together with Freund's incomplete adjuvant (FIA), into female NOD mice at 30 and 45 days old. Diabetes was accelerated 2 weeks later by a single injection of cyclophosphamide (CY), which acts against suppressive mechanisms. Treatment with GAD 524-543 peptide delayed the onset of diabetes and reduced its incidence (28% versus 60%; P < 0 . 001) compared with control mice injected with FIA alone, or GAD peptide 534-553, or an irrelevant peptide. In the same group, the severity of lymphocytic inflammation of pancreatic islets was reduced (P < 0 . 03). Up to 3 months after peptide injections, a strong splenocytic proliferative response occurred in immunized NOD mice against the immunizing peptide alone (but not against a panel of seven other GAD65-derived peptides). After peptide challenge of splenocytes in vitro, protection against CY-accelerated diabetes was associated with higher peptide-specific production of T helper type 2 (Th2)-associated interleukins 4 and 10, whereas Th1-associated interferon-gamma and IL-2 were proportionally less represented. During cotransfer, T splenocytes from GAD 524-543-immunized mice were able to reduce the capacity of T cells from diabetic donors to transfer the disease adoptively (P < 0 . 01), demonstrating the generation of cellular mechanisms that actively suppress the disease. It is concluded that immunization of NOD mice with GAD65 peptide 524-543 can counteract CYaccelerated diabetes, possibly through active cellular suppression linked to a shift of Th1/Th2 balance toward the production of Th2 cytokines such as IL-4 and IL-10. This study provides additional support for the notion that GAD, and more precisely its epitope 524-543, could be one of the key targets for the pathogenesis of type 1 diabetes in NOD mice, as well as for the efficacy of disease-specific peptide therapy in type 1 diabetes.

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“…Human islets only express the GAD6s protein [24,25] and the incidence of GAD67 antibodies in IDDM is low [26,27]. GAD67 does not seem to have an independent role as an autoantigen in IDDM.…”

mentioning

confidence: 99%

“…In addition to GAD6s, GAD is expressed as a second non-allelic form, GAD67 in neurons [23] and in rat and mouse beta cells [24]. Human islets only express the GAD6s protein [24,25] and the incidence of GAD67 antibodies in IDDM is low [26,27].…”

mentioning

confidence: 99%

Value of antibodies to GAD65 combined with islet cell cytoplasmic antibodies for predicting IDDM in a childhood population

Aanstoot

Sigurdsson²,

Jaffe

et al. 1994

Diabetologia

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SummaryThe value of a test for islet cell cytoplasmic antibodies together with a test for GAD6s antibodies to predict the subsequent development of diabetes over a period of 11.5 years was assessed in an open childhood population comprising 2,805 individuals. A single serum sample was obtained from each individual between 1975 and 1977 and screened for islet cell cytoplasmic antibodies for which eight individuals were positive (0.29 %). During the average follow-up period of 11.5 years, four of eight islet cell antibody positive and three islet cell antibody negative individuals developed clinical diabetes. Sera from all individuals, who were islet cell antibody positive and/ or developed diabetes (total of 11) and from 100 randomly selected control subjects were analysed for GAD65 antibodies. Six of eight islet cell antibody positive individuals were GAD65 antibody positive including all four who subsequently developed IDDM. Furthermore, one of the three islet cell antibody negative individuals who developed IDDM was GAD65 antibody positive both in 1976 and in 1989. Thus, a positive test for GAD6s antibodies alone correctly predicted diabetes in five of seven children, who developed the disease. Only one of the children, who developed diabetes was positive for insulin autoantibodies and this individual was also positive for islet cell cytoplasmic antibodies and GAD65 antibodies. One of the 100 control subjects was positive for GAD6s antibodies (1%). The results suggest that a single GAD65 antibody test may have a higher sensitivity for predicting IDDM than a test for islet cell cytoplasmic antibodies, but that a combined positive test for both antibodies increases the specificity for predicting IDDM over a period of 11.5 years. [Diabetologia (1994) 37: 917-924] Key words GAD65 antibodies, islet cell cytoplasmic antibodies, predictive value, IDDM in childhood.The destruction of pancreatic beta cells, which precedes the clinical onset of IDDM, is mediated by autoimmune mechanisms [1]. The presence of islet specific autoantibodies in the pre-diabetic period [2-4] is likely to reflect the ongoing autoimmune process, one that eventually leads to critical beta-cell depletion and insulin dependency. A major goal of diabetes research is to develop immune interventions that block or otherwise interfere with the destruction of beta cells and the development of clinical diabetes. Concomitant with this goal is the necessity for methods for early accurate identification of susceptible individuals [5]. Antibody assays that detect early signs of humoral autoimmunity associated with beta-cell destruction are obvious candidates for this purpose. Furthermore, susceptibility to develop diabetes is associated with certain MHC-class II haplotypes [6] and analysis of both HLA haplotypes and autoantibodies provide a test of high predictive value in family members of IDDM patients [3,7]. Since most new cases of [DDM involve individuals without a first degree relative with the disease [8, 9], predictive meth-

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Differential Expression of GAD65 and GAD67 in Human, Rat, and Mouse Pancreatic Islets

Cited by 139 publications

References 25 publications

Development of autoimmune diabetes in glutamic acid decarboxylase 65 (GAD65) knockout NOD mice

Development of autoimmune diabetes in glutamic acid decarboxylase 65 (GAD65) knockout NOD mice

Immunization of non-obese diabetic (NOD) mice with glutamic acid decarboxylase-derived peptide 524–543 reduces cyclophosphamide-accelerated diabetes

Value of antibodies to GAD65 combined with islet cell cytoplasmic antibodies for predicting IDDM in a childhood population

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