Fused-in-sarcoma (FUS), an RNA binding protein, is a central player in the genetics and pathology of ALS and FTD. Synaptopathy, or synaptic dysfunction, is an early event in neurodegeneration. How synaptic dysfunction leads to neuron death is not known. Recent evidence clearly show that FUS has a physiological role at the presynaptic terminal, and ALS causative mutations in FUS lead to altered synaptic physiology and dysfunction. However, the full physiological role of FUS at the presynaptic terminal, and the consequence of ALS causative FUS mutations on presynaptic function have not been described. We hypothesize that presynaptic FUS plays a physiological role linking synaptic vesicle trafficking and local translation, with ALS causative mutations in FUS leading to synaptopathy.
Identification of novel molecular mechanisms leading to synaptopathy in ALS/FTD, revealing novel therapeutic targets.
1. Delineate alterations to presynaptic physiology in FUS ALS.
2. Quantify presynaptic local protein translation in FUS ALS
3. Define locally translated axo-synaptic proteins altered in FUS ALS.
Techniques and skills
Model system: motor and cortical induced neurons, derived from CRISPR-Cas9 edited iPSCs carrying disease relative FUS mutation (P525L) and isogenic controls.
iPSC-derived neuronal cultures, imaging and analysis (super-resolution, confocal, high-throughput), synaptic endocytosis assays, multi-electrode assays, presynaptic local translation assays, mass-spec, proteomics, western blotting, RT-PCR, microfluidics.
This project will fully describe the effect of FUS ALS mutants on the presynaptic terminal (ultrastructure, vesicle pools, synaptic vesicle exo/endocytosis, synaptic firing). Additionally, this will fully describe the presynaptic translatome, and identify targets whose local translation is altered in FUS-ALS presynaptic terminals.
This work will i) fully describe a fundamental cellular process which is not yet understood (presynaptic local translation), and ii) identify novel therapeutic targets for intervention in ALS/FTD.