Project ID NS-MH2024_12

ThemeNS-MH

Co Supervisor 1A Institute of Psychiatry, Psychology & Neuroscience, School of Neuroscience, Department of Basic & Clinical NeuroscienceWebsite

Co Supervisor 1B Institute of Psychiatry, Psychology & Neuroscience, School of Neuroscience, Department of Basic & Clinical NeuroscienceWebsite

Synaptopathy- The patho-physiological role of FUS at the presynaptic terminal in amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD).

Scientific basis

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.

Translational aspect

Identification of novel molecular mechanisms leading to synaptopathy in ALS/FTD, revealing novel therapeutic targets.

Aims

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.

Over-arching objectives

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.

Representative Publications

Synaptopathy in CHMP2B frontotemporal dementia highlights the synaptic vesicle cycle as a therapeutic target. Robbins M, Clayton EL. Neural Regen Res. 2023 Feb;18(2):315-316. doi: 10.4103/1673-5374.343905.

A novel synaptopathy-defective synaptic vesicle protein trafficking in the mutant CHMP2B mouse model of frontotemporal dementia. Clayton EL, Bonnycastle K, Isaacs AM, Cousin MA, Schorge S. J Neurochem. 2022 Feb;160(3):412-425. doi: 10.1111/jnc.15551.

Frontotemporal dementia causative CHMP2B impairs neuronal endolysosomal traffic-rescue by TMEM106B knockdown. Clayton EL, Milioto C, Muralidharan B, Norona FE, Edgar JR, Soriano A, Jafar-Nejad P, Rigo F, Collinge J, Isaacs AM. Brain. 2018 Dec 1;141(12):3428-3442. doi: 10.1093/brain/awy284.

Identification of a novel interaction of FUS and syntaphilin may explain synaptic and mitochondrial abnormalities caused by ALS mutations. Salam S, Tacconelli S, Smith BN, Mitchell JC, Glennon E, Nikolaou N, Houart C, Vance C. Sci Rep. 2021 Jun 30;11(1):13613. doi: 10.1038/s41598-021-93189-6.

Mitochondrial abnormalities and disruption of the neuromuscular junction precede the clinical phenotype and motor neuron loss in hFUSWT transgenic mice. So E, Mitchell JC, Memmi C, Chennell G, Vizcay-Barrena G, Allison L, Shaw CE, Vance C. Hum Mol Genet. 2018 Feb 1;27(3):463-474. doi: 10.1093/hmg/ddx415.

Mutations in FUS, an RNA processing protein, cause familial amyotrophic lateral sclerosis type 6. Vance C, Rogelj B, Hortobágyi T, De Vos KJ, Nishimura AL, Sreedharan J, Hu X, Smith B, Ruddy D, Wright P, Ganesalingam J, Williams KL, Tripathi V, Al-Saraj S, Al-Chalabi A, Leigh PN, Blair IP, Nicholson G, de Belleroche J, Gallo JM, Miller CC, Shaw CE. Science. 2009 Feb 27;323(5918):1208-1211. doi: 10.1126/science.1165942.