TrkB agonists ameliorate obesity and associated metabolic conditions in mice.
Mutations in the tyrosine kinase receptor trkB or in one of its natural ligands, brain-derived neurotrophic factor (BDNF), lead to severe hyperphagia and obesity in rodents and/or humans. Here, we show that peripheral administration of neurotrophin-4 (NT4), the second natural ligand for trkB, suppresses appetite and body weight in a dose-dependent manner in several murine models of obesity. NT4 treatment increased lipolysis, reduced body fat content and leptin, and elicited long-lasting amelioration of hypertriglyceridemia and hyperglycemia. After treatment termination, body weight gradually recovered to control levels in obese mice with functional leptin receptor. A single intrahypothalamic application of minute amounts of NT4 or an agonist trkB antibody also reduced food intake and body weight in mice. Taken together with the genetic evidence, our findings support the concept that trkB signaling, which originates in the hypothalamus, directly modulates appetite, metabolism, and taste preference downstream of the leptin and melanocortin 4 receptor. The trkB agonists mediate anorexic and weight-reducing effects independent of stress induction, visceral discomfort, or pain sensitization and thus emerge as a potential therapeutic for metabolic disorders.
Rinat Laboratories, Pfizer Inc., 230 East Grand Avenue, South San Francisco, California 94080, USA.
David
D
Tsao
Heather Koenig
HK
Thomsen
Joyce
J
Chou
Jennifer
J
Stratton
Michael
M
Hagen
Carole
C
Loo
Carlos
C
Garcia
David L
DL
Sloane
Arnon
A
Rosenthal
John C
JC
Lin
D000818:Animals; D001835:Body Weight / Q000187:drug effects; D004195:Disease Models, Animal; D004435:Eating / Q000187:drug effects; D004734:Energy Metabolism / Q000187:drug effects; D005947:Glucose / Q000378:metabolism; D006706:Homeostasis / Q000187:drug effects; D020738:Leptin / Q000378:metabolism; D018021:Lithium Chloride / Q000494:pharmacology; D008297:Male; D053486:Melanocortins / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D008820:Mice, Obese; D009414:Nerve Growth Factors / Q000494:pharmacology*; D009765:Obesity / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D020813:Receptor, trkB / Q000819:agonists* / Q000378:metabolism; D054411:Receptors, Leptin / Q000378:metabolism; D013649:Taste / Q000187:drug effects; D014280:Triglycerides / Q000378:metabolism
D020738:Leptin; D053486:Melanocortins; D009414:Nerve Growth Factors; D054411:Receptors, Leptin; D014280:Triglycerides; D020813:Receptor, trkB; D018021:Lithium Chloride; D005947:Glucose; C073922:neurotrophin 4