Speaker
Description
"Huntington disease (HD) is a late-onset and progressive neurodegenerative condition caused by an expanded CAG repeat residing in exon1 of the Huntington gene (HTT). In recent years, there has been a shift in prospective about the pathogenic mechanisms underlying HD, moving beyond traditional protein-centric vision to embrace new DNA-based driving hypothesis. Accordingly, inherited CAG repeats can expand in somatic tissues, especially in post-mitotic neurons, giving rise to a HTT mosaicism that results in longer than inherited CAG tracts in affected tissues, such as the striatum and cortex. This expansion may continue during the lifetime of the individual contributing to exacerbate (or initiate) neuronal toxicity and selective degeneration. More recently, trans- and cis- modifiers of age of onset (AOO) have been identified. However, if and how they cause the progressive accumulation of CAG instability is not fully understood.
Here, we show a human stem cell-based platform (CAGinSTEM) capable of modelling HD repeat instability over time in mitotic cells and post-mitotic neurons. Thanks to the design based on targeted engineering of a Recombination Mediated Cassette Exchange at the HTT exon1, this platform allows for easy and flexible manipulation of the HTT CAG repeat with change in size and composition, providing a unique biological model system to study genotype-phenotype relationship in different cell types in vitro. Moreover, the platform is amenable to pooled screening approach that coupled to single nuclei RNA sequencing (snRNAseq) and CAG sizing, allows for high-throughput analysis of gene expression and repeat instability in individual cells. This powerful combination can offer unprecedented insights into the molecular mechanisms driving CAG instability and its downstream effects, paving the way for new therapeutic targets in HD research."
| Author(s) | Dario Besusso 1,2, Martina Zobel 1,2, Christian Cassarino 1,2, Gianluca Damaggio 1,2,3, Maria Lidia Mignogna 1,2, Davide Scalzo 1,2, Paola Conforti 1,2, Ilaria Campus 1,2, Andrea Cossu 1,2, Francesco Cortina 1,2, Simone Maestri 1,2, Vincenza Colonna 4,5, Chiara Zuccato 1,2, Elena Cattaneo 1,2 |
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| Affiliation(s) | "1 University of Milan, Milan, Italy 2 Istituto Nazionale Genetica Molecolare, Milan, Italy 3 University of Naples Federico II, Naples, Italy 4 National Research Council, Institute of Genetics and Biophysics, Naples, Italy 5 University of Tennessee, Knoxville, Tennessee" |
