Abstract
A better understanding of processes controlling the development and function of pancreatic islets is critical for diabetes prevention and treatment. Here, we reveal a previously unappreciated function for pancreatic β2-adrenergic receptors (Adrb2) in controlling glucose homeostasis by restricting islet vascular growth during development. Pancreas-specific deletion of Adrb2 results in glucose intolerance and impaired insulin secretion in mice, and unexpectedly, specifically in females. The metabolic phenotypes were recapitulated by Adrb2 deletion from neonatal, but not adult, β-cells. Mechanistically, Adrb2 loss increases production of Vascular Endothelial Growth Factor-A (VEGF-A) in female neonatal β-cells and results in hyper-vascularized islets during development, which in turn, disrupts insulin production and exocytosis. Neonatal correction of islet hyper-vascularization, via VEGF-A receptor blockade, fully rescues functional deficits in glucose homeostasis in adult mutant mice. These findings uncover a regulatory pathway that functions in a sex-specific manner to control glucose metabolism by restraining excessive vascular growth during islet development.
Highlights
Glucose homeostasis is maintained by secretion of the insulin hormone from islets of Langerhans in the pancreas
a previously uncharacterized role for b2adrenergic receptors (Adrb2) is required in neonatal b-cells for glucose homeostasis and insulin secretion in female mice
Islet endothelial cells are critical for regulation of insulin biosynthesis and exocytosis in neighboring b-cells
Summary
Glucose homeostasis is maintained by secretion of the insulin hormone from islets of Langerhans in the pancreas. We identify a pancreas-specific requirement for the b2-adrenergic receptor (Adrb2) in controlling glucose homeostasis by suppressing VEGF-A production in b-cells and limiting vascular growth in islets during development. Pancreas-specific loss of Adrb results in glucose intolerance and impaired glucose-stimulated insulin secretion, which surprisingly, was observed only in female mice. Developmental blockade of VEGF-A signaling corrects islet hyper-vascularization in neonatal mice and rescues glucose intolerance and insulin secretion defects in adult Adrb mutant mice. These findings reveal Adrb as a negative regulator that controls islet development and glucose metabolism by influencing bi-directional communication between islet b-cells and the vasculature
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