Peripheral huntingtin silencing does not ameliorate central signs of disease in the B6.HttQ111/+ mouse model of Huntington’s disease

• Published in: PloS one Vol. 12; no. 4; p. e0175968
• Main Authors: Coffey, Sydney R., Bragg, Robert M., Minnig, Shawn, Ament, Seth A., Cantle, Jeffrey P., Glickenhaus, Anne, Shelnut, Daniel, Carrillo, José M., Shuttleworth, Dominic D., Rodier, Julie-Anne, Noguchi, Kimihiro, Bennett, C. Frank, Price, Nathan D., Kordasiewicz, Holly B., Carroll, Jeffrey B.
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 01.04.2017; Public Library of Science (PLoS)
• Subjects: Ablation; Adipose tissue; Adipose Tissue, Brown - metabolism; Adipose Tissue, White - metabolism; Age; Alterations; Ammonia; Animal models; Animals; Antisense oligonucleotides; Atrophy; Automation; Bacterial artificial chromosomes; Behavior, Animal; Biodegradation; Bioinformatics; Biology; Biology and Life Sciences; Blood-brain barrier; Body weight; Bone marrow; Bone marrow transplantation; Brain - metabolism; Carriers; Cell death; Central nervous system; Circuits; Cognition; Computer applications; Computer programs; Degradation; Disease; Disease Models, Animal; Disease Progression; Drugs; Emotional behavior; Etiology; Fasting; Gene expression; Gene Silencing; Genetics; Genomes; Glucose; Hereditary diseases; Huntingtin Protein - deficiency; Huntingtin Protein - genetics; Huntington Disease - genetics; Huntington Disease - metabolism; Huntington Disease - pathology; Huntingtons disease; Immune response; Liver; Liver - metabolism; Liver diseases; Mathematical analysis; Medicine; Medicine and Health Sciences; Mice; Mood; Mortality; Mutation; Nervous system; Neurodegenerative diseases; Neurons; Neurosciences; Nucleic acids; Organs; Phenotype; Position (location); Preservation; Psychology; Research and Analysis Methods; Restoration; Ribonucleic acid; RNA; Rodents; Sheep; Studies; Substrates; Tissues; Transplantation; Urea
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0175968

Huntington's disease (HD) is an autosomal dominant neurodegenerative disease whose predominant neuropathological signature is the selective loss of medium spiny neurons in the striatum. Despite this selective neuropathology, the mutant protein (huntingtin) is found in virtually every cell so far studied, and, consequently, phenotypes are observed in a wide range of organ systems both inside and outside the central nervous system. We, and others, have suggested that peripheral dysfunction could contribute to the rate of progression of striatal phenotypes of HD. To test this hypothesis, we lowered levels of huntingtin by treating mice with antisense oligonucleotides (ASOs) targeting the murine Huntingtin gene. To study the relationship between peripheral huntingtin levels and striatal HD phenotypes, we utilized a knock-in model of the human HD mutation (the B6.HttQ111/+ mouse). We treated mice with ASOs from 2-10 months of age, a time period over which significant HD-relevant signs progressively develop in the brains of HttQ111/+ mice. Peripheral treatment with ASOs led to persistent reduction of huntingtin protein in peripheral organs, including liver (64% knockdown), brown adipose (66% knockdown), and white adipose tissues (71% knockdown). This reduction was not associated with alterations in the severity of HD-relevant signs in the striatum of HttQ111/+ mice at the end of the study, including transcriptional dysregulation, the accumulation of neuronal intranuclear inclusions, and behavioral changes such as subtle hypoactivity and reduced exploratory drive. These results suggest that the amount of peripheral reduction achieved in the current study does not significantly impact the progression of HD-relevant signs in the central nervous system.