Gut-Specific Neprilysin Deletion Protects Against Fat-Induced Insulin Secretory Dysfunction In Male Mice.

Abstract

Neprilysin is a ubiquitous peptidase that can modulate glucose homeostasis by cleaving insulinotropic peptides. While global deletion of neprilysin protects mice against high fat diet (HFD)-induced insulin secretory dysfunction, strategies to ablate neprilysin in a tissue-specific manner are favored to limit off-target effects. Since insulinotropic peptides are produced in the gut, we sought to determine whether gut-specific neprilysin deletion confers beneficial effects on insulin secretion similar to that of global neprilysin deletion in mice fed HFD. Mice with conditional deletion of neprilysin in enterocytes (NEPGut-/-) were generated by crossing Vil-Cre and floxed neprilysin (NEPfl/fl) mice. Neprilysin activity was almost abolished throughout the gut in NEPGut-/- mice, and was similar in plasma, pancreas and kidney in NEPGut-/- vs control mice. An oral glucose tolerance test was performed at baseline and following 14 weeks of HFD feeding, during which glucose tolerance and glucose-stimulated insulin secretion (GSIS) were assessed. Despite similar body weight gain at 14 weeks, NEPGut-/- displayed lower fasting plasma glucose levels, improved glucose tolerance and increased GSIS compared to control mice. In conclusion, gut-specific neprilysin deletion recapitulates the enhanced GSIS seen with global neprilysin deletion in high-fat-fed mice. Thus, strategies to inhibit neprilysin specifically in the gut may protect against fat-induced glucose intolerance and beta-cell dysfunction.