Marked differences in neurochemistry and aggregates despite similar behavioural and neuropathological features of Huntington disease in the full-length BACHD and YAC128 mice.
The development of animal models of Huntington disease (HD) has enabled studies that help define the molecular aberrations underlying the disease. The BACHD and YAC128 transgenic mouse models of HD harbor a full-length mutant huntingtin (mHTT) and recapitulate many of the behavioural and neuropathological features of the human condition. Here, we demonstrate that while BACHD and YAC128 animals exhibit similar deficits in motor learning and coordination, depressive-like symptoms, striatal volume loss and forebrain weight loss, they show obvious differences in key features characteristic of HD. While YAC128 mice exhibit significant and widespread accumulation of mHTT striatal aggregates, these mHTT aggregates are absent in BACHD mice. Furthermore, the levels of several striatally enriched mRNA for genes, such as DARPP-32, enkephalin, dopamine receptors D1 and D2 and cannabinoid receptor 1, are significantly decreased in YAC128 but not BACHD mice. These findings may reflect sequence differences in the human mHTT transgenes harboured by the BACHD and YAC128 mice, including both single nucleotide polymorphisms as well as differences in the nature of CAA interruptions of the CAG tract. Our findings highlight a similar profile of HD-like behavioural and neuropathological deficits and illuminate differences that inform the use of distinct endpoints in trials of therapeutic agents in the YAC128 and BACHD mice.
Centre for Molecular Medicine and Therapeutics, University of British Columbia, and Child and Family Research Institute, Vancouver, BC, Canada.
Mahmoud A
MA
Pouladi
Lisa M
LM
Stanek
Yuanyun
Y
Xie
Sonia
S
Franciosi
Amber L
AL
Southwell
Yu
Y
Deng
Stefanie
S
Butland
Weining
W
Zhang
Seng H
SH
Cheng
Lamya S
LS
Shihabuddin
Michael R
MR
Hayden
D000818:Animals; D004195:Disease Models, Animal; D005260:Female; D000071058:Huntingtin Protein; D006816:Huntington Disease / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D009419:Nerve Tissue Proteins / Q000235:genetics* / Q000378:metabolism; D009474:Neurons / Q000378:metabolism* / Q000473:pathology; D019076:Transgenes
C086055:HTT protein, human; D000071058:Huntingtin Protein; D009419:Nerve Tissue Proteins