The Q175 mouse model of Huntington's disease shows gene dosage- and age-related decline in circadian rhythms of activity and sleep

• Published in: PloS one Vol. 8; no. 7; p. e69993
• Main Authors: Loh, Dawn H, Kudo, Takashi, Truong, Danny, Wu, Yingfei, Colwell, Christopher S
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 30-07-2013; Public Library of Science (PLoS)
• Subjects: Age; Age Factors; Alleles; Animal cognition; Animal models; Animals; Biological clocks; Biology; Circadian rhythm; Circadian Rhythm - genetics; Circadian rhythms; Copy number; Disease Models, Animal; Disruption; Gene Dosage; Gene expression; Genotype; Humans; Huntingtin; Huntingtin Protein; Huntington Disease - genetics; Huntington Disease - metabolism; Huntington Disease - physiopathology; Huntington's disease; Huntingtons disease; Insertion; Laboratory animals; Locomotor activity; Male; Medical treatment; Medicine; Mice; Mice, Transgenic; Motor Activity - genetics; Mutation; Nerve Tissue Proteins - genetics; Nerve Tissue Proteins - metabolism; Neurodegenerative diseases; Neurological diseases; Psychiatry; Rodents; Sleep; Sleep - genetics; Suprachiasmatic nucleus; Transgenic; Los Angeles California; United States > US; California
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0069993

Sleep and circadian disruptions are commonly reported by patients with neurodegenerative diseases, suggesting these may be an endophenotype of the disorders. Several mouse models of Huntington's disease (HD) that recapitulate the disease progression and motor dysfunction of HD also exhibit sleep and circadian rhythm disruption. Of these, the strongest effects are observed in the transgenic models with multiple copies of mutant huntingtin gene. For developing treatments of the human disease, knock-in (KI) models offer advantages of genetic precision of the insertion and control of mutation copy number. Therefore, we assayed locomotor activity and immobility-defined sleep in a new model of HD with an expansion of the KI repeats (Q175). We found evidence for gene dose- and age-dependent circadian disruption in the behavior of the Q175 line. We did not see evidence for loss of cells or disruption of the molecular oscillator in the master pacemaker, the suprachiasmatic nucleus (SCN). The combination of the precise genetic targeting in the Q175 model and the observed sleep and circadian disruptions make it tractable to study the interaction of the underlying pathology of HD and the mechanisms by which the disruptions occur.