In vivo cell-autonomous transcriptional abnormalities revealed in mice expressing mutant huntingtin in striatal but not cortical neurons.

TitleIn vivo cell-autonomous transcriptional abnormalities revealed in mice expressing mutant huntingtin in striatal but not cortical neurons.
Publication TypeJournal Article
Year of Publication2011
AuthorsThomas, EA, Coppola G, Tang B, Kuhn A, Kim SH, Geschwind DH, Brown TB, Luthi-Carter R, Ehrlich ME
JournalHuman molecular genetics
Volume20
Issue6
Pagination1049-60
Date Published2011 Mar 15
ISSN1460-2083
KeywordsAnimals, Cells, Cultured, cerebral cortex, Corpus Striatum, Disease Models, Animal, Gene Expression Regulation, Humans, Huntington Disease, Male, Mice, Mice, Transgenic, Mutation, Nerve Tissue Proteins, Neurons, Nuclear Proteins, Organ Specificity, Transcription, Genetic, Trinucleotide Repeat Expansion
Abstract

Huntington's disease (HD), caused by a CAG repeat expansion in the huntingtin (HTT) gene, is characterized by abnormal protein aggregates and motor and cognitive dysfunction. Htt protein is ubiquitously expressed, but the striatal medium spiny neuron (MSN) is most susceptible to dysfunction and death. Abnormal gene expression represents a core pathogenic feature of HD, but the relative roles of cell-autonomous and non-cell-autonomous effects on transcription remain unclear. To determine the extent of cell-autonomous dysregulation in the striatum in vivo, we examined genome-wide RNA expression in symptomatic D9-N171-98Q (a.k.a. DE5) transgenic mice in which the forebrain expression of the first 171 amino acids of human Htt with a 98Q repeat expansion is limited to MSNs. Microarray data generated from these mice were compared with those generated on the identical array platform from a pan-neuronal HD mouse model, R6/2, carrying two different CAG repeat lengths, and a relatively high degree of overlap of changes in gene expression was revealed. We further focused on known canonical pathways associated with excitotoxicity, oxidative stress, mitochondrial dysfunction, dopamine signaling and trophic support. While genes related to excitotoxicity, dopamine signaling and trophic support were altered in both DE5 and R6/2 mice, which may be either cell autonomous or non-cell autonomous, genes related to mitochondrial dysfunction, oxidative stress and the peroxisome proliferator-activated receptor are primarily affected in DE5 transgenic mice, indicating cell-autonomous mechanisms. Overall, HD-induced dysregulation of the striatal transcriptome can be largely attributed to intrinsic effects of mutant Htt, in the absence of expression in cortical neurons.

DOI10.1111/j.1460-9568.2012.08054.x
Alternate JournalHum. Mol. Genet.