Heterogeneity in glutamic acid decarboxylase expression among single rat pancreatic beta cells

M. C. Sánchez-Soto, M. E. Larrieta, R. Vidaltamayo, M. Hiriart

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

Aims/hypothesis. An isoform of glutamic acid decarboxylase, (GAD)65 has been identified as a pancreatic beta-cell autoantigen in Type I (insulin dependent) diabetes mellitus. We investigated the expression of GAD isoforms among single rat beta cells in culture, under different conditions and the correlation between GAD65 expression and insulin secretion-rate. Results. Independent of culture conditions, 100% of fresh and cultured beta cells express GAD67. In contrast, considerable heterogeneity in GAD65 expression among single beta cells was observed. After 2 days in culture in 2.6 mmol/1 glucose, only 24% of the beta cells express GAD65. This percentage increases to 39% in 5.6 mmol/1 glucose and to 54% and 56 % in 11.6 mmol/1 and 20.6 mmol/1 glucose, respectively. Moreover, reducing glucose concentration from 11.6 to 2.5 mmol/1 for 2 days, reduces GAD65 expression by nearly 30%. After 11 days in culture with 11.6 mmol/1 glucose, 50% of beta cells continue expressing GAD65, this percentage is further increased to nearly 75% by including either nerve growth factor or dibutyryl cyclic AMP or both in the culture medium. When beta cells are challenged for 1 h with 20.6 mmol/1 glucose, 67% respond forming insulin-immunoplaques. More than two-thirds of insulin-secretors are GAD65-positive, in contrast to only 11% of the non- secreting cells. Moreover, 87% of beta cells that have a high insulin secretory rate express GAD65. Conclusion/interpretation. These results show that the most active beta cells, which secrete more insulin, also express GAD65 and that manipulating extracellular glucose may modify the expression of the enzyme and possibly the autoimmune attack in Type I diabetes.
Original languageEnglish
Pages (from-to)1086-1092
Number of pages7
JournalDiabetologia
DOIs
Publication statusPublished - 7 Sep 1999
Externally publishedYes

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Glutamate Decarboxylase
Insulin-Secreting Cells
Glucose
Insulin
Type 1 Diabetes Mellitus
Protein Isoforms
Secretory Rate
Bucladesine
Autoantigens
Nerve Growth Factor
Culture Media
Cultured Cells
Cell Culture Techniques
Enzymes

All Science Journal Classification (ASJC) codes

  • Internal Medicine
  • Endocrinology, Diabetes and Metabolism

Cite this

Sánchez-Soto, M. C. ; Larrieta, M. E. ; Vidaltamayo, R. ; Hiriart, M. / Heterogeneity in glutamic acid decarboxylase expression among single rat pancreatic beta cells. In: Diabetologia. 1999 ; pp. 1086-1092.
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abstract = "Aims/hypothesis. An isoform of glutamic acid decarboxylase, (GAD)65 has been identified as a pancreatic beta-cell autoantigen in Type I (insulin dependent) diabetes mellitus. We investigated the expression of GAD isoforms among single rat beta cells in culture, under different conditions and the correlation between GAD65 expression and insulin secretion-rate. Results. Independent of culture conditions, 100{\%} of fresh and cultured beta cells express GAD67. In contrast, considerable heterogeneity in GAD65 expression among single beta cells was observed. After 2 days in culture in 2.6 mmol/1 glucose, only 24{\%} of the beta cells express GAD65. This percentage increases to 39{\%} in 5.6 mmol/1 glucose and to 54{\%} and 56 {\%} in 11.6 mmol/1 and 20.6 mmol/1 glucose, respectively. Moreover, reducing glucose concentration from 11.6 to 2.5 mmol/1 for 2 days, reduces GAD65 expression by nearly 30{\%}. After 11 days in culture with 11.6 mmol/1 glucose, 50{\%} of beta cells continue expressing GAD65, this percentage is further increased to nearly 75{\%} by including either nerve growth factor or dibutyryl cyclic AMP or both in the culture medium. When beta cells are challenged for 1 h with 20.6 mmol/1 glucose, 67{\%} respond forming insulin-immunoplaques. More than two-thirds of insulin-secretors are GAD65-positive, in contrast to only 11{\%} of the non- secreting cells. Moreover, 87{\%} of beta cells that have a high insulin secretory rate express GAD65. Conclusion/interpretation. These results show that the most active beta cells, which secrete more insulin, also express GAD65 and that manipulating extracellular glucose may modify the expression of the enzyme and possibly the autoimmune attack in Type I diabetes.",
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Heterogeneity in glutamic acid decarboxylase expression among single rat pancreatic beta cells. / Sánchez-Soto, M. C.; Larrieta, M. E.; Vidaltamayo, R.; Hiriart, M.

In: Diabetologia, 07.09.1999, p. 1086-1092.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Heterogeneity in glutamic acid decarboxylase expression among single rat pancreatic beta cells

AU - Sánchez-Soto, M. C.

AU - Larrieta, M. E.

AU - Vidaltamayo, R.

AU - Hiriart, M.

PY - 1999/9/7

Y1 - 1999/9/7

N2 - Aims/hypothesis. An isoform of glutamic acid decarboxylase, (GAD)65 has been identified as a pancreatic beta-cell autoantigen in Type I (insulin dependent) diabetes mellitus. We investigated the expression of GAD isoforms among single rat beta cells in culture, under different conditions and the correlation between GAD65 expression and insulin secretion-rate. Results. Independent of culture conditions, 100% of fresh and cultured beta cells express GAD67. In contrast, considerable heterogeneity in GAD65 expression among single beta cells was observed. After 2 days in culture in 2.6 mmol/1 glucose, only 24% of the beta cells express GAD65. This percentage increases to 39% in 5.6 mmol/1 glucose and to 54% and 56 % in 11.6 mmol/1 and 20.6 mmol/1 glucose, respectively. Moreover, reducing glucose concentration from 11.6 to 2.5 mmol/1 for 2 days, reduces GAD65 expression by nearly 30%. After 11 days in culture with 11.6 mmol/1 glucose, 50% of beta cells continue expressing GAD65, this percentage is further increased to nearly 75% by including either nerve growth factor or dibutyryl cyclic AMP or both in the culture medium. When beta cells are challenged for 1 h with 20.6 mmol/1 glucose, 67% respond forming insulin-immunoplaques. More than two-thirds of insulin-secretors are GAD65-positive, in contrast to only 11% of the non- secreting cells. Moreover, 87% of beta cells that have a high insulin secretory rate express GAD65. Conclusion/interpretation. These results show that the most active beta cells, which secrete more insulin, also express GAD65 and that manipulating extracellular glucose may modify the expression of the enzyme and possibly the autoimmune attack in Type I diabetes.

AB - Aims/hypothesis. An isoform of glutamic acid decarboxylase, (GAD)65 has been identified as a pancreatic beta-cell autoantigen in Type I (insulin dependent) diabetes mellitus. We investigated the expression of GAD isoforms among single rat beta cells in culture, under different conditions and the correlation between GAD65 expression and insulin secretion-rate. Results. Independent of culture conditions, 100% of fresh and cultured beta cells express GAD67. In contrast, considerable heterogeneity in GAD65 expression among single beta cells was observed. After 2 days in culture in 2.6 mmol/1 glucose, only 24% of the beta cells express GAD65. This percentage increases to 39% in 5.6 mmol/1 glucose and to 54% and 56 % in 11.6 mmol/1 and 20.6 mmol/1 glucose, respectively. Moreover, reducing glucose concentration from 11.6 to 2.5 mmol/1 for 2 days, reduces GAD65 expression by nearly 30%. After 11 days in culture with 11.6 mmol/1 glucose, 50% of beta cells continue expressing GAD65, this percentage is further increased to nearly 75% by including either nerve growth factor or dibutyryl cyclic AMP or both in the culture medium. When beta cells are challenged for 1 h with 20.6 mmol/1 glucose, 67% respond forming insulin-immunoplaques. More than two-thirds of insulin-secretors are GAD65-positive, in contrast to only 11% of the non- secreting cells. Moreover, 87% of beta cells that have a high insulin secretory rate express GAD65. Conclusion/interpretation. These results show that the most active beta cells, which secrete more insulin, also express GAD65 and that manipulating extracellular glucose may modify the expression of the enzyme and possibly the autoimmune attack in Type I diabetes.

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JO - Diabetologia

JF - Diabetologia

SN - 0012-186X

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