Abstract
Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder caused by a CAG trinucleotide repeat expansion in the huntingtin gene. Major pathological hallmarks of HD include inclusions of mutant huntingtin (mHTT) protein, loss of neurons predominantly in the caudate nucleus, and atrophy of multiple brain regions. However, the early sequence of histological events that manifest in region- and cell-specific manner has not been well characterized. Here we use a high-content histological approach to precisely monitor changes in HTT expression and characterize deposition dynamics of mHTT protein inclusion bodies in the recently characterized zQ175 knock-in mouse line. We carried out an automated multi-parameter quantitative analysis of individual cortical and striatal cells in tissue slices from mice aged 2-12 months and confirmed biochemical reports of an age-associated increase in mHTT inclusions in this model. We also found distinct regional and subregional dynamics for inclusion number, size and distribution with subcellular resolution. We used viral-mediated suppression of total HTT in the striatum of zQ175 mice as an example of a therapeutically-relevant but heterogeneously transducing strategy to demonstrate successful application of this platform to quantitatively assess target engagement and outcome on a cellular basis.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Cerebral Cortex / metabolism
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Corpus Striatum / metabolism
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Disease Models, Animal
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Fluorescent Antibody Technique
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Gene Knockdown Techniques
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Heterozygote
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Huntingtin Protein
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Huntington Disease / genetics*
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Huntington Disease / metabolism*
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Huntington Disease / pathology
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Inclusion Bodies*
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Intranuclear Inclusion Bodies
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Mice
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Mice, Transgenic
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Nerve Tissue Proteins / genetics*
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Nerve Tissue Proteins / metabolism*
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Nuclear Proteins / genetics*
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Nuclear Proteins / metabolism*
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Phenotype
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Protein Aggregation, Pathological
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Protein Transport
Substances
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Htt protein, mouse
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Huntingtin Protein
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Nerve Tissue Proteins
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Nuclear Proteins
Grants and funding
This work was supported by CHDI Foundation, a privately-funded nonprofit biomedical research organization exclusively dedicated to discovering and developing therapeutics that slow the progression of Huntington's disease. CHDI Foundation conducts research in a number of different ways; for the purposes of this manuscript, research was conducted at the contract research organization Evotec AG under a fee-for-service agreements. The authors listed all contributed to the conception, planning, and direction of the research, including generation, analysis, and interpretation of the data. The specific roles of these authors are articulated in the author contributions section.