A well-known and commonly used model to study molecular aspects of Huntington disease are the striatum-derived STHdhcell lines generated coming from wild type andhuntingtinknock-in mouse embryos. interpreting results. Here, we demonstrate that STHdhcell lines display differences in cell size, proliferation rate and chromosomal content. While the chromosomal divergence is considered to be a result of the cells tumour characteristics, differences in size and proliferation, however , were verified in a second non-immortalized Huntington disease cell model. Importantly, our results further suggest that the reported phenotypes can confound other study final results and lead to false findings. Thus, careful experimental design and data analysis are advised when using these cell models. == Introduction == Huntington disease (HD) is usually an inherited, fatal, neurodegenerative disorder. It results from a CAG replicate expansion in the geneHTT, coding for the huntingtin protein. The mutation is translated into an elongated polyglutamine repeat in huntingtin, which leads to the disruption of various mobile signalling pathways and leads to impaired cell function and ultimately Rabbit Polyclonal to EMR2 cell death, particularly of striatal neurons1, 2 . To study mobile and molecular mechanisms contributing to the HD pathogenesis, several cell and animal versions have been generated. The STHdhcell lines were generated coming from an HD knock- in mouse model3, which carries the endogenousHdhgene (mouse Huntington disease gene homolog) with a chimeric exon 14and is usually characterized by a mild LM22A-4 behavioural phenotype and neuropathological features5. These cell lines derive coming from striatal primordia3and express wild-type and mutant huntingtin at endogenous levels6. The precise genetic context and the striatal origin of the cells make the STHdhcell lines a widely used model in HD research. By comparing immortalized striatal precursor cells coming from wild type mice (STHdhQ7/Q7cells) to precursor cells derived from heterozygous and homozygousHdhQ111knock-in mice (STHdhQ7/Q111and STHdhQ111/Q111cells), differences in a variety of HD-related mobile pathways have been discovered or confirmed, for instance an involvement of huntingtin in calcium handling LM22A-4 deficits and mitochondrial dysfunction711or effects on various signalling cascades1214. Despite the currently unquestioned usefulness and importance of this model, apparent but rarely reported differences in size11, shape15and proliferation price might demand caution when using the STHdhcell lines. The origin of those differences, their importance to get HD, as well as the consequences to get the meaning of research outcomes remains largely unaddressed. In this research, we show that the STHdhcell lines show divergent characteristics, which interfere with commonly used assays and hamper the direct comparison of both cell lines. We further show that these features are partially shared by mouse embryonic fibroblast (MEFHdh) cell lines generated from the same animal model and their outrageous type littermates, which implies a common, HD-related mechanism past immortalization artefacts. Overall, these findings argue for a comprehensive characterization of every cell range used and the inclusion of such confounding factors in the experimental design. == Results == == Reduced cell size is a characteristic of STHdhQ111/Q111and MEFHdhQ111/Q111cells == We performed a morphometric analysis of homozygous STHdhQ111/Q111(STQ111) and wild type STHdhQ7/Q7(STQ7) cells by light microscopy and flow cytometry analysis. Measurement of the surface area of cells attached to the culture dish revealed a significantly smaller cell surface area in the mutant STHdhcells (Fig. 1a and b; P < 0. 001). The smaller cell size of STHdhQ111/Q111was also found in detached cells, both when measuring the surface area from microscopic images (Supplementary Fig. S1) and on a larger scale by flow cytometry analysis (Fig. 1c and d). Here, the family member mean forward-scatter area (FSC-A), which is positively related to cell size, was 32% lower in STHdhQ111/Q111than in STHdhQ7/Q7cells (Fig. 1d; P= 0. 013). Similar differences were also seen after differentiation into neuron-like cells (Supplementary Fig. S2). == Physique 1 . == Cell size difference in Q111 knock-in cells. (a) Representative pictures of STHdhQ7/Q7(STQ7) and STHdhQ111/Q111(STQ111) cells, and (b) ImageJ-based surface area quantification of STHdhcells attached to the culture dish surface n = three or more experiments, unpairedt-tests; ***P < 0. 001. (c) Agent histograms of STHdhcells and (d) quantification of the cell size of live cells in suspension, based on the family member mean forward scatter area LM22A-4 (FSC-A); n = 4 experiments, unpairedt-tests; *P < 0. 05. (eh) Results of size determination to get MEFHdhQ7/Q7(MEFQ7) and MEFHdhQ111/Q111(MEFQ111) cells, respectively; *P < 0. 05, **P < 0. 01. To assess whether this cell size phenotype is usually cell line-specific or whether it might be regarded as a general feature of HD, we performed the same set of experiments in a fibroblast cell line established from the same mouse model (MEFHdhcells). Like in the STHdhcells, the mutant MEFHdhQ111/Q111(MEFQ111) cells had a smaller cell surface area compared to the outrageous type MEFHdhQ7/Q7(MEFQ7) cells, when the cells were attached to.