Resveratrol and curcumin enhance pancreatic β-cell function by inhibiting phosphodiesterase activity
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Figure 1
Resveratrol (RES) and curcumin (CUR) enhance insulin secretion in pancreatic β-cells. Mouse β-Min6 cells were treated with (A) RES or (B) CUR for 2 h under low- (1 mmol/l) or high- (25 mmol/l) glucose conditions. Primary human islets (n=2 donors) were incubated with (C) RES or (D) CUR for 2 h under low- (5 mmol/l) or high- (25 mmol/l) glucose conditions. Supernatants from triplicate samples were analyzed for insulin secretion (*P<0.05, **P<0.01, ***P<0.001, and ****P<0.0001). Data are representative of at least three independent experiments.
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Figure 2
Resveratrol (RES) and curcumin (CUR) increase intracellular cAMP levels in β-cells. Mouse β-Min6 cells were treated with (A) RES or (B) CUR for 2 h under low- (1 mmol/l) or high- (25 mmol/l) glucose conditions. Primary human islets were treated with (C) RES or (D) CUR for 2 h under low- (5 mmol/l) or high- (25 mmol/l) glucose conditions (n=2 donors). Cells were lysed and assessed for intracellular cAMP levels after normalizing to protein content in triplicates (*P<0.05). Data are representative of at least three independent experiments.
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Figure 3
PDE blockade leads to enhanced insulin secretion and intracellular cAMP production. Mouse β-Min6 cells were treated with PDE inhibitor IBMX (50 μmol/l) for 2 h under low- (1 mmol/l) or high- (25 mmol/l) glucose conditions. Cells were examined for (A) insulin secretion and (B) intracellular cAMP levels (normalized to protein content; *P<0.05, **P<0.01, and ****P<0.0001). Samples were run in triplicate, and data are representative of at least three independent experiments.
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Figure 4
Resveratrol (RES) and curcumin (CUR) reduce PDE expression in β-cells. (A) Mouse β-Min6 cells and (B) human HP62 β-cells were incubated with vehicle, RES (0.1 μmol/l), or CUR (1 pmol/l) for 2 h under low- (1 mmol/l) or high- (25 mmol/l) glucose conditions. (C) Primary human islets (n=3 donors) were incubated with vehicle, RES (10 μmol/l), or CUR (100 pmol/l) for 2 h under low (5 mmol/l) or high (25 mmol/l) glucose conditions. Samples, ran in triplicate, were analyzed for relative PDE mRNA expression using quantitative RT-PCR and results are expressed as mean±s.e.m. (*P<0.05, **P<0.01, ***P<0.001, ****P<0.0001). Data are representative of at least three independent experiments.
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Figure 5
Resveratrol (RES) and curcumin (CUR) impede PDE activity in pancreatic β-cells. (A) Mouse β-Min6 cells and (B) human HP62 β-cells were cultured for 2 h under low- (1 mmol/l) or high- (25 mmol/l) glucose conditions. (C) Primary human islets (n=2 donors) were cultured for 2 h under low- (5 mmol/l) or high- (25 mmol/l) glucose conditions. Cell lysates were treated with vehicle, RES, or CUR and analyzed for relative PDE activity using a bioluminescence reaction assay. Samples were run in triplicates and the mean was plotted (*P<0.05, **P<0.01, ***P<0.001, and ****P<0.0001). Data are representative of at least three independent experiments.
- © 2014 The authors
