Monolayer Culture of Adult Rat Pancreatic Islets on Extracellular Matrix: Long Term Maintenance of Differentiated B-Cell Function*

Kaiser, Nurit; Corcos, A; Tur-Sinai, A.; Ariav, Y.; Cerasi, E

doi:10.1210/endo-123-2-834

Cited by 50 publications

(28 citation statements)

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“…Diabetes, defined by random blood glucose levels >8.3 mmol/l, was induced by feeding a high-energy diet (14.23 kJ/g; Teklad Global Diets, Boston, MA, USA) [16]. Islets were isolated from normoglycaemic and diabetic P. obesus by collagenase digestion (Collagenase P; Roche Diagnostics, Mannheim, Germany) as described [17]. The islets were used after repeated washes with Hanks' balanced salt solution.…”

Section: Methodsmentioning

confidence: 99%

Insulin counteracts glucotoxic effects by suppressing thioredoxin-interacting protein production in INS-1E beta cells and in Psammomys obesus pancreatic islets

et al. 2009

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Aims/hypothesis In type 2 diabetes, glucose toxicity leads to beta cell apoptosis with decreased beta cell mass as a consequence. Thioredoxin-interacting protein (TXNIP) is a critical mediator of glucose-induced beta cell apoptosis. Since hyperglycaemia leads to elevated serum insulin, we hypothesised that insulin is involved in the regulation of TXNIP protein levels in beta cells. Methods We studied the production of TXNIP in INS-1E beta cells and in islets of Psammomys obesus, an animal model of type 2 diabetes, in response to glucose and different modulators of insulin secretion. Results TXNIP production was markedly augmented in islets from diabetic P. obesus and in beta cells exposed to high glucose concentration. In contrast, adding insulin to the culture medium or stimulating insulin secretion with different secretagogues suppressed TXNIP. Inhibition of glucose and fatty acid-stimulated insulin secretion with diazoxide increased TXNIP production in beta cells. Nitric oxide (NO), a repressor of TXNIP, enhanced insulin signal transduction, whereas inhibition of NO synthase abolished its activation, suggesting that TXNIP inhibition by NO is mediated by stimulation of insulin signalling. Treatment of beta cells chronically exposed to high glucose with insulin reduced beta cell apoptosis. Txnip knockdown mimicking the effect of insulin prevented glucose-induced beta cell apoptosis. Conclusions/interpretation Insulin is a potent repressor of TXNIP, operating a negative feedback loop that restrains the stimulation of TXNIP by chronic hyperglycaemia. Repression of TXNIP by insulin is probably an important compensatory mechanism protecting beta cells from oxidative damage and apoptosis in type 2 diabetes.

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Section: Methodsmentioning

confidence: 99%

Insulin counteracts glucotoxic effects by suppressing thioredoxin-interacting protein production in INS-1E beta cells and in Psammomys obesus pancreatic islets

et al. 2009

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“…Islets were maintained in suspension (for short-term studies) or cultured as monolayer patches on extracellular matrixcoated dishes (12); the latter procedure is advantageous because it preserves the ␤-cell differentiated phenotype over prolonged time and circumvents artifacts that complicate the interpretation of studies of islets in long-term suspension culture (14,15). RPMI 1640, modified to include different concentrations of glucose (3.3-33.3 mmol/l) and 10% fetal bovine serum, was used as culture medium.…”

Section: In Vitro Modulation Of ␤-Cell Function By Chronic Exposure Tmentioning

confidence: 99%

beta-cell glucotoxicity in the Psammomys obesus model of type 2 diabetes.

et al. 2001

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Deficient insulin secretion and relative hyperproinsulinemia are characteristic features of type 2 diabetes. The gerbil Psammomys obesus appears to be an ideal natural model of the human disease because it shows increased tendency to develop diet-induced diabetes, which is associated with moderate obesity. The disease is characterized by initial hyperinsulinemia, progressing to hypoinsulinemia associated with depleted pancreatic insulin stores and an increased proportion of insulin precursor molecules in the blood and islets. Although the proinsulin translational efficacy was found to be increased in hyperglycemic animals, insulin mRNA levels were not augmented and exhibited a gradual decrease with disease progression. The development of hyperglycemia was associated with a transient increase in ␤-cell proliferative activity, as opposed to a prolonged increase in the rate of ␤-cell death, culminating in disruption of islet architecture. The hypothesis that glucotoxicity is responsible in part for these in vivo changes was investigated in vitro in primary islet cultures. Islets from diabetes-prone P. obesus cultured at high glucose concentrations displayed changes in ␤-cell function that mimic those observed in diabetic animals. These changes include deficient insulin secretion, depleted insulin content, an increased proportion of insulin precursor molecules, a progressive increase of DNA fragmentation, and a transient proliferative response. Furthermore, insulin mRNA was not increased by short-term exposure of P. obesus islets to elevated glucose in vitro. It is proposed that ␤-cell glucotoxicity in P. obesus results from the inability of proinsulin biosynthesis to keep pace with chronic insulin hypersecretion. The resulting depletion of the insulin stores may be related to deficient glucose-regulated insulin gene transcription, possibly due to defective PDX-1 (pancreatic duodenal homeobox factor-1) expression in the adult P. obesus. An additional glucotoxic effect involves the loss of ␤-cell mass in hyperglycemic P. obesus as a result of progressive ␤-cell death without an adequate increase in the rate of ␤-cell proliferation. Diabetes 50 (Suppl. 1):S113-S117, 2001 THE PSAMMOMYS OBESUS MODEL OF TYPE 2 DIABETESThe gerbil Psammomys obesus, nicknamed the sand rat, is a diurnal rodent that serves as a model for type 2 diabetes. In its native arid habitat in the North African and Eastern Mediterranean deserts, the P. obesus feeds mainly on the low-calorie salt bush (Atriplex halimus) and exhibits neither obesity nor diabetes. However, when transferred to laboratory conditions of nutritional abundance, it shows a propensity to develop diabetes associated with moderate obesity and insulin resistance (1,2). The genetic background for nutrition-evoked diabetes was demonstrated in the Jerusalem colony of P. obesus by selection of two outbred lines of animals: diabetes-prone (DP) and partially diabetes-resistant (DR) P. obesus (3,4). Most animals of the DP line under the age of 4 months develop diabetes when switched from ...

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“…13 Several cell-secreted matrices have been used to improve islet culture and study interactions between insulinproducing cells and matrix molecules. Matrix secreted by bovine corneal endothelial cells improved islet survival 14 and insulin secretion 15 and induced adult b-cell proliferation. 1 Studies of rat b-cells cultured on matrix produced using a rat bladder carcinoma line (804G) focused on specific integrin interactions and their effect on cell survival, spreading, and insulin secretion.…”

Section: Introductionmentioning

confidence: 97%

Cell–Matrix Interactions Improve β-Cell Survival and Insulin Secretion in Three-Dimensional Culture

Weber

Hayda

Anseth

2008

Tissue Engineering Part A

209

192

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Controlled matrix interactions were presented to pancreatic b-cells in three-dimensional culture within poly (ethylene glycol) hydrogels. Dispersed MIN6 b-cells were encapsulated in gel environments containing the following entrapped extracellular matrix (ECM) proteins: collagen type I, collagen type IV, fibrinogen, fibronectin, laminin, and vitronectin. In ECM-containing gels, b-cell survival was significantly better than in gels without ECM over 10 days. Correspondingly, apoptosis in encapsulated b-cells was less in the presence of each matrix protein, suggesting the ability of individual matrix interactions to prevent matrix signaling-related apoptosis (anoikis). MIN6 b-cells cultured in gels containing collagen type IV or laminin secreted more insulin in response to glucose stimulation than b-cells in all other experimental conditions. Variations in collagen type IV or laminin concentration between 10 mg=mL and 250 mg=mL did not affect insulin secretion. Finally, b-cell function in hydrogels presenting both collagen type IV and laminin revealed synergistic interactions. With a total protein concentration of 100 mg=mL, three gel compositions of varying ratios of collagen type IV to laminin (25:75, 50:50, and 75:25) were tested. In the presence of 25 mg=mL of collagen type IV and 75 mg=mL of laminin, bcell insulin secretion was greater than with laminin or collagen type IV individually. These results demonstrate that specific, rationally designed extracellular environments promote isolated b-cell survival and function.

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Monolayer Culture of Adult Rat Pancreatic Islets on Extracellular Matrix: Long Term Maintenance of Differentiated B-Cell Function*

Cited by 50 publications

References 0 publications

Insulin counteracts glucotoxic effects by suppressing thioredoxin-interacting protein production in INS-1E beta cells and in Psammomys obesus pancreatic islets

Insulin counteracts glucotoxic effects by suppressing thioredoxin-interacting protein production in INS-1E beta cells and in Psammomys obesus pancreatic islets

beta-cell glucotoxicity in the Psammomys obesus model of type 2 diabetes.

Cell–Matrix Interactions Improve β-Cell Survival and Insulin Secretion in Three-Dimensional Culture

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