Stimulation of insulin secretion reveals heterogeneity of pancreatic B cells in vivo.

Stefan, Y; Meda, Paolo; Neufeld, Michel; Orci, Lelio

doi:10.1172/jci113045

Cited by 153 publications

(137 citation statements)

References 31 publications

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“…As expected from previous rodent studies [26,30], homologous contacts between human beta cells potentiated insulin secretion. In addition, and for the first time, we showed that a single intercellular contact between an alpha cell and a beta cell was able to increase insulin secretion.…”

Section: Discussionsupporting

confidence: 87%

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Insulin secretion from human beta cells is heterogeneous and dependent on cell-to-cell contacts

Wojtusciszyn

Armanet²,

Morel³

et al. 2008

Diabetologia

133

102

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Aims/hypothesis We assessed the heterogeneity of insulin secretion from human isolated beta cells and its regulation by cell-to-cell contacts. Methods Insulin secretion from single and paired cells was assessed by a reverse haemolytic plaque assay. The percentage of plaque-forming cells, the mean plaque area and the total plaque development were evaluated after 1 h of stimulation with different secretagogues. Results Not all beta cells were surrounded by a haemolytic plaque under all conditions tested. A small fraction of the beta cell population (20%) secreted more than 90% and 70% of total insulin at 2.2 and 22.2 mmol/l glucose, respectively. Plaque-forming cells, mean plaque area and total plaque development were increased at 12.2 and 22.2 compared with 2.2 mmol/l glucose. Insulin secretion of single beta cells was similar at 12.2 and 22.2 mmol/l glucose. Insulin secretion of beta cell pairs was increased compared with that of single beta cells and was higher at 22.2 than at 12.2 mmol/l glucose. Insulin secretion of beta cells in contact with alpha cells was also increased compared with single beta cells, but was similar at 22.2 compared with 12.2 mmol/l glucose. Delta and other non-beta cells did not increase insulin secretion of contacting beta cells compared with that of single beta cells. Differences in insulin secretion between 22.2 and 12.2 mmol/l glucose were observed in murine but not in human islets. Conclusions/interpretation Human beta cells are highly heterogeneous in terms of insulin secretion so that a small fraction of beta cells contributes to the majority of insulin secreted. Homologous and heterologous intercellular contacts have a significant impact on insulin secretion and this could be related to the particular architecture of human islets.

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Section: Discussionsupporting

confidence: 87%

“…There is no evidence in our data that this pattern of secretion exists in whole islets. In rats, heterogeneous secretion of islet beta cells has been demonstrated in vivo by systemic perfusion of glucose and glibenclamide [30]. Of course, this kind of experiment is impossible in humans.…”

Section: Discussionmentioning

confidence: 99%

Insulin secretion from human beta cells is heterogeneous and dependent on cell-to-cell contacts

Wojtusciszyn

Armanet²,

Morel³

et al. 2008

Diabetologia

133

102

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“…The amounts of both NCAM and integrins have thus been shown to differ from one b-cell to the next (Bosco et al 2000, Bernard-Kargar et al 2001, and functional heterogeneity has been documented by several groups (Salomon & Meda 1986, Stefan et al 1987, Pralong et al 1990, Soria et al 1991, van Schravendijk et al 1992. In the present study, the strongest labeling of E-cadherin was observed in the more central part of islets, corresponding to b-cells that have the higher insulin secretion activity (Stefan et al 1987). To further investigate whether a correlation does exist between E-cadherin expression and insulin secretion, we sorted by FACS a poorly labeled and a highly labeled b-cell population.…”

Section: Discussionmentioning

confidence: 99%

Differential expression of E-cadherin at the surface of rat β-cells as a marker of functional heterogeneity

Bosco¹,

Rouiller²,

Halban³

2007

Journal of Endocrinology

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The aim of this study was to assess whether the expression of E-cadherin at the surface of rat b-cells is regulated by insulin secretagogues and correlates with insulin secretion. When cultured under standard conditions, virtually all b-cells expressed E-cadherin observed by immunofluorescence, but heterogeneous staining was observed. Using fluorescence-activated cell sorting (FACS), two b-cell sub-populations were sorted: one that was poorly labeled ('ECad-low') and another that was highly labeled ('ECad-high'). After 1-h stimulation with 16 . 7 mM glucose, insulin secretion (reverse hemolytic plaque assay) from individual ECad-high b-cells was higher than that from ECad-low b-cells. Ca 2C-dependent b-cell aggregation was increased at 16 . 7 mM glucose when compared with 2 . 8 mM glucose. E-cadherin at the surface of b-cells was increased after 18 h at 11 . 1 and 22 . 2 mM glucose when compared with 2 . 8 mM glucose, with the greatest increase at 22 . 2 mM glucoseC0 . 5 mM isobutylmethylxanthine (IBMX).While no labeling was detected on freshly trypsinized cells, the proportion of stained cells increased in a time-dependent manner during culture for 1, 3, and 24 h. This recovery was faster when cells were incubated at 16 . 7 vs 2 . 8 mM glucose. Cycloheximide inhibited expression of E-cadherin at 2 . 8 mM glucose, but not at 16 . 7 mM, while depolymerization of actin by either cytochasin B or latrunculin B increased surface Ecadherin at low glucose. In conclusion, these results show that expression of E-cadherin at the surface of islet b-cells is controlled by secretagogues including glucose, correlates with insulin secretion, and can serve as a surface marker of b-cell function.

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“…digestion (9,10). They were cultured on epithelial cell matrix (Becton Dickinson) in the presence of RPMI 1640 media (Life Technologies, Rockville, MD) supplemented with 11 mM glucose at 37°C and 5% CO 2 for Ϸ14 days before being used in experiments.…”

Section: Methodsmentioning

confidence: 99%

Separation of the glucose-stimulated cytoplasmic and mitochondrial NAD(P)H responses in pancreatic islet β cells

Patterson

Knobel

Arkhammar

et al. 2000

Proc. Natl. Acad. Sci. U.S.A.

261

216

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Two-photon excitation microscopy was used to image and quantify NAD(P)H autofluorescence from intact pancreatic islets under glucose stimulation. At maximal glucose stimulation, the rise in whole-cell NAD(P)H levels was estimated to be Ϸ30 M. However, because glucose-stimulated insulin secretion involves both glycolytic and Kreb's cycle metabolism, islets were cultured on extracellular matrix that promotes cell spreading and allows spatial resolution of the NAD(P)H signals from the cytoplasm and mitochondria. The metabolic responses in these two compartments are shown to be differentially stimulated by various nutrient applications. The glucose-stimulated increase of NAD(P)H fluorescence within the cytoplasmic domain is estimated to be Ϸ7 M. Likewise, the NAD(P)H increase of the mitochondrial domain is Ϸ60 M and is delayed with respect to the change in cytoplasmic NAD(P)H by Ϸ20 sec. The large mitochondrial change in glucose-stimulated NAD(P)H thus dominates the total signal but may depend on the smaller but more rapid cytoplasmic increase.G lucose-induced insulin secretion is coupled to the metabolic state of the ␤ cell. After transport into the cell, glucose is phosphorylated and shunted into glycolysis, which increases metabolic flux. This altered metabolic state, which can be monitored by NAD(P)H autofluorescence increase, leads to an increase in the ATP͞ADP ratio that closes the plasma membrane-associated ATP-sensitive potassium (K ATP ) channel. Closure of this channel depolarizes the membrane, leading to the activation of voltage-sensitive calcium (Ca 2ϩ ) channels, Ca 2ϩ influx, and insulin secretion (1).Glucose usage in stimulated pancreatic ␤ cells is principally glycolytic, with the polyol pathway, glycogen synthesis, and pentose phosphate pathway accounting for Ͻ10% of total usage (2). Thus, the glucose metabolic signal is derived from glycolysis in the cytoplasm and pyruvate metabolism in the mitochondria. The absence of stimulated insulin secretion with nonmetabolizable glucose derivatives (1) and the abolition of glucosestimulated insulin secretion in a pancreatic ␤ cell line lacking mitochondrial DNA (3) suggest roles for both cytoplasmic and mitochondrial metabolism in normal secretion. Additionally, both glycolytic intermediates, such as glyceraldehyde 3-phosphate and dihydroxyacetone phosphate (2), and mitochondrial substrates, such as leucine (4) or methyl pyruvate (5), stimulate insulin secretion, which further supports a role for metabolism in both compartments in glucose signaling.Attempts to resolve the glycolytic and mitochondrial contributions to glucose-stimulated insulin secretion have relied on nutrient secretagogues that couple at various points into glycolysis or Kreb's cycle or on pharmacological inhibition at various points along each pathway (1, 6). Although various nutrient supplements indicate that couplings of the pathway can lead to insulin secretion, they seldom mimic the effects of glucose. For example, pyruvate potentiates glucose-stimulated secretion but does not cause s...

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Stimulation of insulin secretion reveals heterogeneity of pancreatic B cells in vivo.

Cited by 153 publications

References 31 publications

Insulin secretion from human beta cells is heterogeneous and dependent on cell-to-cell contacts

Insulin secretion from human beta cells is heterogeneous and dependent on cell-to-cell contacts

Differential expression of E-cadherin at the surface of rat β-cells as a marker of functional heterogeneity

Separation of the glucose-stimulated cytoplasmic and mitochondrial NAD(P)H responses in pancreatic islet β cells

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