Cytoplasmic dynein is a large multi-subunit microtubule associated protein involved in a range of cellular processes including transport of cargo in the minus-end direction (retrograde transport). We and others have shown that mutations in the heavy chain subunit of cytoplasmic dynein (Dync1h1) in the Legs at odd angles (Loa), Abnormal rear leg (Arl), Cramping 1 (Cra1), and Sprawling (Swl) mouse models cause neurodegeneration as a result of perturbation of neuron-specific functions of dynein. We have shown that the F580Y and W1206R substitutions in DYNC1H1 in the Loa and Arl, respectively, result in severe loss of motor and sensory neurones. Analysis of the cells isolate from Loa and Arl suggest that the neuronal loss in these mice is a result of significant defects in the dynein-mediated retrograde axonal transport and endocytic membrane trafficking of trophic factors. Interestingly mutations in dynactin – a multi-subunit protein partner of dynein, which contributes to retrograde transport and regulates dynein function– have been identified in human families with a late-onset form of motor neurone disease. These mouse models, therefore, provide invaluable tools for elucidating the mechanisms that control and regulate the motor and cargo transport functions of dynein, and its role in neuronal health and disease. However, large numbers of mice and lengthy breeding and dissection schemes are needed to obtain the required motor and sensory primary neurones for such analyses. Thus, in this application we are proposing to produce ‘induced pluripotent stem (iPS) cells' from mouse embryonic fibroblasts (MEFs) isolated from Loa and Arl mice, by following the detailed and well established protocol described by Yamanaka and colleagues. We will then be able to differentiate these iPS cells into neuronal cells using established protocols. All the expertise for carrying out this project is available in our groups. Successful completion of this project will result in significant reduction in breeding mice with harmful mutations in dynein, and in time and costs involved in their breeding and the experimental procedures. In addition, we will be able to share the iPS cells with other labs around the world and signify the use of iPS-cell technology in studying other mouse models.
Garrett CA et al. (2014). DYNC1H1 mutation alters transport kinetics and ERK1/2-cFos signalling in a mouse model of distal spinal muscular atrophy. Brain 137(Pt 7):1883-93. doi: 10.1093/brain/awu097
- Research Review 2011: iPS cells to reduce animal use in motor neurone disease research