Type 2 diabetes is characterized by insulin resistance and inadequate insulin secretion. In the advanced stages of the disease, beta -cell dysfunction worsens and insulin therapy maybe necessary to achieve satisfactory metabolic control. Studies in autopsies found decreased beta -cell mass in pancreas of people with type 2 diabetes. Apoptosis, a constitutive program of cell death modulated by the Eel family genes, has been implicated in loss of beta -cells in animal models of type 2 diabetes. in this study, we compared the effect of 5 days' culture in high glucose concentration (16.7 mmol/l) versus normal glucose levels (5.5 mmol/l) or hyperosmolar control (mannitol 11 mmol/l plus glucose 5 mmol/l) on the survival of human pancreatic islets. Apoptosis, analyzed by flow cytometry and electron and immunofluorescence microscopy, was increased in islets cultured in high glucose (HG5) as compared with normal glucose (NG5) or hyperosmolar control (NG5+MAN5). We also analyzed by reverse transcriptase-polymerase chain reaction and Western blotting the expression of the Bcl family genes in human islets cultured in normal glucose or high glucose. The antiapoptotic gene Bcl-2 was unaffected by glucose change, whereas Bcl-xl was reduced upon treatment with HG5. On the other hand, proapoptotic genes Bad, Bid, and Bik were overexpressed in the islets maintained in HG5. To define the pancreatic localization of Bcl proteins, me performed confocal immunofluorescence analysis on human pancreas. Bad and Bid mere specifically expressed in beta -cells, and Bid was also expressed, although at low levels, in the exocrine pancreas. Bik and Bcl-xl were expressed in other endocrine islet cells as well as in the exocrine pancreas. These data suggest that in human islets, high glucose may modulate the balance of proapoptotic and antiapoptotic Eel proteins toward apoptosis, thus favoring beta -cell death.

Federici M., H.M. (2001). High glucose causes apoptosis in cultured human pancreatic islets of Langerhans: A potential role for regulation of specific Bcl family genes toward an apoptotic cell death program. DIABETES, 50(6), 1290-1301.

High glucose causes apoptosis in cultured human pancreatic islets of Langerhans: A potential role for regulation of specific Bcl family genes toward an apoptotic cell death program

FEDERICI, MASSIMO;MELINO, GENNARO;LAURO, RENATO;
2001

Abstract

Type 2 diabetes is characterized by insulin resistance and inadequate insulin secretion. In the advanced stages of the disease, beta -cell dysfunction worsens and insulin therapy maybe necessary to achieve satisfactory metabolic control. Studies in autopsies found decreased beta -cell mass in pancreas of people with type 2 diabetes. Apoptosis, a constitutive program of cell death modulated by the Eel family genes, has been implicated in loss of beta -cells in animal models of type 2 diabetes. in this study, we compared the effect of 5 days' culture in high glucose concentration (16.7 mmol/l) versus normal glucose levels (5.5 mmol/l) or hyperosmolar control (mannitol 11 mmol/l plus glucose 5 mmol/l) on the survival of human pancreatic islets. Apoptosis, analyzed by flow cytometry and electron and immunofluorescence microscopy, was increased in islets cultured in high glucose (HG5) as compared with normal glucose (NG5) or hyperosmolar control (NG5+MAN5). We also analyzed by reverse transcriptase-polymerase chain reaction and Western blotting the expression of the Bcl family genes in human islets cultured in normal glucose or high glucose. The antiapoptotic gene Bcl-2 was unaffected by glucose change, whereas Bcl-xl was reduced upon treatment with HG5. On the other hand, proapoptotic genes Bad, Bid, and Bik were overexpressed in the islets maintained in HG5. To define the pancreatic localization of Bcl proteins, me performed confocal immunofluorescence analysis on human pancreas. Bad and Bid mere specifically expressed in beta -cells, and Bid was also expressed, although at low levels, in the exocrine pancreas. Bik and Bcl-xl were expressed in other endocrine islet cells as well as in the exocrine pancreas. These data suggest that in human islets, high glucose may modulate the balance of proapoptotic and antiapoptotic Eel proteins toward apoptosis, thus favoring beta -cell death.
Pubblicato
Rilevanza internazionale
Articolo
Sì, ma tipo non specificato
Settore M-EDF/01 - Metodi e Didattiche delle Attivita' Motorie
Settore MED/09 - Medicina Interna
English
Con Impact Factor ISI
gene product; glucose; protein BAD; protein bcl; unclassified drug; apoptosis; article; cell survival; controlled study; electron microscopy; flow cytometry; gene expression; human; human cell; immunofluorescence microscopy; pancreas islet; pancreas islet beta cell; priority journal; protein localization; reverse transcription polymerase chain reaction; Apoptosis; Cells, Cultured; Dose-Response Relationship, Drug; Fluorescent Antibody Technique; Gene Expression Regulation; Glucose; Humans; Islets of Langerhans; Proto-Oncogenes; Tissue Distribution; Transcription, Genetic
Federici M., H.M. (2001). High glucose causes apoptosis in cultured human pancreatic islets of Langerhans: A potential role for regulation of specific Bcl family genes toward an apoptotic cell death program. DIABETES, 50(6), 1290-1301.
Federici, M; Hribal, M; Perego, L; Ranalli, M; Caradonna, Z; Perego, C; Usellini, L; Nano, R; Bonini, P; Bertuzzi, F; Marlier, Lnjl; Davalli, Am; Carandente, O; Pontiroli, Ae; Melino, G; Marchetti, P; Lauro, R; Sesti, G; Folli, F
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/2108/53523
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