AMP-ACTIVATED PROTEIN KINASE AS REGULATOR OF P2Y6 RECEPTOR-INDUCED INSULIN SECRETION IN MOUSE PANCREATIC β-CELLS

Abstract 5′-AMP-activated protein kinase (AMPK) and its pharmacological modulators have been targeted for treating type 2 diabetes. Extracellular uridine 5′-diphosphate (UDP) activates P2Y 6 receptors (P2Y 6 Rs) in pancreatic β-cells to release insulin and reduce apoptosis, which would benefit diabetes. Here, we studied the role of P2Y 6 R in activation of AMPK in MIN6 mouse pancreatic β-cells and insulin secretion. Treatment with a potent P2Y 6 R dinucleotide agonist MRS2957 (500 nM) activated AMPK, which was blocked by P2Y 6 R-selective antagonist MRS2578. Also, MRS2957 induced phosphorylation of acetyl-coenzyme A carboxylase (ACC), a marker of AMPK activity. Calcium chelator BAPTA-AM, calmodulin-dependent protein kinase kinase (CaMKK) inhibitor STO-069 and IP 3 receptor antagonist 2-APB attenuated P2Y 6 R-mediated AMPK phosphorylation revealing involvement of intracellular Ca 2+ pathways. P2Y 6 R agonist induced insulin secretion at high glucose, which was reduced by AMPK siRNA. Thus, P2Y 6 R has a crucial role in β-cell function, suggesting its potential as a therapeutic target in diabetes.