Ablation of TrkB signalling in CCK neurons results in hypercortisolism and obesity

Nat Commun. 2014 Mar 12;5:3427. doi: 10.1038/ncomms4427.

Abstract

Dysregulation of hypothalamic-pituitary-adrenal (HPA) axis activity leads to debilitating neuroendocrine or metabolic disorders such as Cushing's syndrome (CS). Glucocorticoids control HPA axis activity through negative feedback to the pituitary gland and the central nervous system (CNS). However, the cellular mechanisms involved are poorly understood, particularly in the CNS. Here we show that, in mice, selective loss of TrkB signalling in cholecystokinin (CCK)-GABAergic neurons induces glucocorticoid resistance, resulting in increased corticotrophin-releasing hormone expression, chronic hypercortisolism, adrenocortical hyperplasia, glucose intolerance and mature-onset obesity, reminiscent of the human CS phenotype. Interestingly, obesity is not due to hyperphagia or decreased energy expenditure, but is associated with increased de novo lipogenesis in the liver. Our study therefore identifies CCK neurons as a novel and critical cellular component of the HPA axis, and demonstrates the requirement of TrkB for the transmission of glucocorticoid signalling.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Body Composition / drug effects
  • Calorimetry, Indirect
  • Cholecystokinin / genetics
  • Cholecystokinin / metabolism*
  • Cushing Syndrome / genetics
  • Cushing Syndrome / metabolism*
  • Eating / drug effects
  • Female
  • GABAergic Neurons / drug effects
  • GABAergic Neurons / metabolism*
  • Immunoblotting
  • In Situ Hybridization
  • Male
  • Membrane Glycoproteins / genetics
  • Membrane Glycoproteins / metabolism*
  • Mice
  • Mifepristone / pharmacology
  • Obesity / genetics
  • Obesity / metabolism*
  • Protein-Tyrosine Kinases / genetics
  • Protein-Tyrosine Kinases / metabolism*

Substances

  • Membrane Glycoproteins
  • Mifepristone
  • Cholecystokinin
  • Ntrk2 protein, mouse
  • Protein-Tyrosine Kinases