%0 Figure %A Pratt, Evan P. S. %A Harvey, Kyle E. %A Salyer, Amy E. %A Hockerman, Gregory H. %D 2019 %T Regulation of basal cAMP levels by PDEs in human pancreatic β-cells. %U https://plos.figshare.com/articles/figure/Regulation_of_basal_cAMP_levels_by_PDEs_in_human_pancreatic_-cells_/9727181 %R 10.1371/journal.pone.0215188.g002 %2 https://plos.figshare.com/ndownloader/files/17420882 %K PDE 4 activity %K subtype-selective PDE inhibitors %K rat insulinoma cell line INS %K PDE 3 %K PDE 4 inhibitor rolipram %K PDE 4 inhibition %K potentiate glucose-stimulated insulin secretion %K 18 mM glucose %K cAMP levels %K CREB %K potentiated insulin secretion %K PDE 1 %K PDE 3 inhibitor cilostamide %K 1.7 mM glucose %K FRET-based cAMP sensor %K PDE 1 inhibitor 8 MM-IBMX %K PDE 3 inhibition %K PDE 4 inhibition potentiated cAMP levels %K 16.7 mM glucose %K PDE 1 inhibition %X

A-C) Subtype-selective PDE inhibitors and IBMX raise cAMP levels in pancreatic β-cells dissociated from human islets under basal conditions (1.7 mM glucose). For each experiment, IBMX (100 μM) and either 8MM-IBMX (100 μM) (A), cilostamide (1 μM) (B) or rolipram (10 μM) (C) were perfused onto the cell. Pancreatic β-cells were identified at the end of each experiment by addition of GLP-1 (50 nM) with and without the α2-receptor agonist clonidine (1 μM). Data shown are representative experiments from single human pancreatic β-cells. D) The percent increase in cAMP levels above baseline elicited by PDE inhibitors in human pancreatic β-cells under basal conditions. IBMX, cilostamide and rolipram significantly elevate cAMP levels above baseline. The percent increase in cAMP levels stimulated by 8MM-IBMX and rolipram is significantly less than that of IBMX (***, P < 0.001, *, P < 0.05 compared to baseline; ###, P < 0.001 compared to IBMX; One-way ANOVA, Tukey post-hoc test). Data shown are average ± SE from 15 cells (8MM-IBMX), 7 cells (cilostamide), 9 cells (rolipram) and 33 cells (IBMX), collected from four human islet preparations. One outlier was removed for IBMX and three outliers were removed for rolipram. E) Resting cAMP levels (mTurquoise2/FRET) in β-cells from eight different human donors. Comparison of pooled data from human β-cells (61 total) to resting cAMP levels in INS-1 cells (41 total) revealed a significantly greater resting cAMP level in human β-cells (***, P < 0.001; Student’s unpaired t-test). Individual data points are shown for each cell measured. Lines represent means ± SE.

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