Characterization of the melanocortin-4-receptor nonsense mutation W16X in vitro and in vivo

• Published in: The pharmacogenomics journal Vol. 13; no. 1; pp. 80 - 93
• Main Authors: Bolze, F, Rink, N, Brumm, H, Kühn, R, Mocek, S, Schwarz, A-E, Kless, C, Biebermann, H, Wurst, W, Rozman, J, Klingenspor, M
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.02.2013; Nature Publishing Group
• Subjects: 631/1647/1513/1967; 631/208/212/1728; 631/208/737; 631/443/319/1642/393; Amikacin; Aminoglycoside antibiotics; Aminoglycosides; Aminoglycosides - genetics; Aminoglycosides - metabolism; Animals; Biomedical and Life Sciences; Biomedicine; Body Composition - genetics; Body length; Body Temperature - genetics; Body Weight - genetics; Cell culture; Cell Line; Cell receptors; Central nervous system; Cercopithecus aethiops; Codon, Nonsense; COS Cells; Energy Intake - genetics; Gene Expression; Gene Expression - genetics; Gene mutations; Gene targeting; Genetic aspects; Genetic disorders; Gentamicin; Glucose tolerance; HEK293 Cells; Human Genetics; Humans; Hyperphagia; Hypothalamus - metabolism; Melanocortin; Melanocortin MC4 receptors; Mice; Mice, Inbred C57BL; Mutation; Nonsense mutation; Obesity; Obesity - genetics; Obesity - metabolism; Oncology; original-article; Pharmacotherapy; Physiological aspects; Psychopharmacology; Receptor, Melanocortin, Type 4 - genetics; Receptor, Melanocortin, Type 4 - metabolism; Germany; aminoglycosides; nonsense suppression; obesity; melanocortin-4-receptor
• ISSN: 1470-269X; 1473-1150; 1473-1150
• DOI: 10.1038/tpj.2011.43

Several genetic diseases are triggered by nonsense mutations leading to the formation of truncated and defective proteins. Aminoglycosides have the capability to mediate a bypass of stop mutations during translation thus resulting in a rescue of protein expression. So far no attention has been directed to obesity-associated stop mutations as targets for nonsense suppression. Herein, we focus on the characterization of the melanocortin-4-receptor ( MC4R ) nonsense allele W16X identified in obese subjects. Cell culture assays revealed a loss-of-function of Mc4r X16 characterized by impaired surface expression and defect signaling. The aminoglycoside G-418 restored Mc4r X16 function in vitro demonstrating that Mc4r X16 is susceptible to nonsense suppression. For the evaluation of nonsense suppression in vivo , we generated a Mc4r X16 knock-in mouse line by gene targeting. Mc4r X16 knock-in mice developed hyperphagia, impaired glucose tolerance, severe obesity and an increased body length demonstrating that this new mouse model resembles typical characteristics of Mc4r deficiency. In a first therapeutic trial, the aminoglycosides gentamicin and amikacin induced no amelioration of obesity. Further experiments with Mc4r X16 knock-in mice will be instrumental to establish nonsense suppression for Mc4r as an obesity-associated target gene expressed in the central nervous system.