Urocortin3 mediates somatostatin-dependent negative feedback control of insulin secretion

• Published in: Nature medicine Vol. 21; no. 7; pp. 769 - 776
• Main Authors: van der Meulen, Talitha, Donaldson, Cynthia J, Cáceres, Elena, Hunter, Anna E, Cowing-Zitron, Christopher, Pound, Lynley D, Adams, Michael W, Zembrzycki, Andreas, Grove, Kevin L, Huising, Mark O
• Format: Journal Article
• Language: English
• Published: New York Nature Publishing Group US 01.07.2015; Nature Publishing Group
• Subjects: 13/109; 13/31; 14/19; 38/39; 38/91; 631/443/319/1557; 631/443/319/1642/137/773; 64/110; 64/60; 692/163; 692/699/2743/137/773; 82/51; Adolescent; Adult; Aged; Animals; Biomedicine; Cancer Research; Child; Child, Preschool; Diabetes Mellitus - genetics; Diabetes Mellitus - pathology; Feedback, Physiological; Female; Gene Expression Regulation; Genetic aspects; HEK293 Cells; Hormones; Humans; Hyperglycemia - genetics; Hyperglycemia - pathology; Infant; Infant, Newborn; Infectious Diseases; Insulin; Insulin - metabolism; Insulin Secretion; Insulin-Secreting Cells - metabolism; Macaca; Male; Metabolic Diseases; Mice, Inbred C57BL; Middle Aged; Models, Biological; Molecular Medicine; Neurosciences; Pancreatic beta cells; Paracrine Communication; Peptides; Physiological aspects; Physiology; Somatostatin; Somatostatin - metabolism; Tissue Donors; Transcriptome - genetics; Urocortins - deficiency; Urocortins - metabolism; Young Adult; United States
• ISSN: 1078-8956; 1546-170X
• DOI: 10.1038/nm.3872

Ucn3 is released from pancreatic beta cells along with insulin, and it engages a negative feedback loop by promoting somatostatin secretion from delta cells to control further insulin secretion. The peptide hormone urocortin3 (Ucn3) is abundantly expressed by mature beta cells, yet its physiological role is unknown. Here we demonstrate that Ucn3 is stored and co-released with insulin and potentiates glucose-stimulated somatostatin secretion via cognate receptors on delta cells. Further, we found that islets lacking endogenous Ucn3 have fewer delta cells, reduced somatostatin content, impaired somatostatin secretion, and exaggerated insulin release, and that these defects are rectified by treatment with synthetic Ucn3 in vitro . Our observations indicate that the paracrine actions of Ucn3 activate a negative feedback loop that promotes somatostatin release to ensure the timely reduction of insulin secretion upon normalization of plasma glucose. Moreover, Ucn3 is markedly depleted from beta cells in mouse and macaque models of diabetes and in human diabetic islets. This suggests that Ucn3 is a key contributor to stable glycemic control, whose reduction during diabetes aggravates glycemic volatility and contributes to the pathophysiology of this disease.