C9orf72 and RAB7L1 regulate vesicle trafficking in amyotrophic lateral sclerosis and frontotemporal dementia

Yoshitsugu Aoki, Raquel Manzano, Yi Lee, Ruxandra Dafinca, Misako Aoki, Andrew G.L. Douglas, Miguel A. Varela, Chaitra Sathyaprakash, Jakub Scaber, Paola Barbagallo, Pieter Vader, Imre Mäger, Kariem Ezzat, Martin R. Turner, Naoki Ito, Samanta Gasco, Norihiko Ohbayashi, Samir El Andaloussi, Shin'ichi Takeda, Mitsunori FukudaKevin Talbot, Matthew J.A. Wood

    Research output: Contribution to journalArticlepeer-review

    69 Citations (Scopus)

    Abstract

    A non-coding hexanucleotide repeat expansion in intron 1 of the C9orf72 gene is the most common cause of amyotrophic lateral sclerosis and frontotemporal dementia (C9ALS/FTD), however, the precise molecular mechanism by which the C9orf72 hexanucleotide repeat expansion directs C9ALS/FTD pathogenesis remains unclear. Here, we report a novel disease mechanism arising due to the interaction of C9ORF72 with the RAB7L1 GTPase to regulate vesicle trafficking. Endogenous interaction between C9ORF72 and RAB7L1 was confirmed in human SH-SY5Y neuroblastoma cells. The C9orf72 hexanucleotide repeat expansion led to haploinsufficiency resulting in severely defective intracellular and extracellular vesicle trafficking and a dysfunctional trans-Golgi network phenotype in patient-derived fibroblasts and induced pluripotent stem cell-derived motor neurons. Genetic ablation of RAB7L1or C9orf72 in SH-SY5Y cells recapitulated the findings in C9ALS/FTD fibroblasts and induced pluripotent stem cell neurons. When C9ORF72 was overexpressed or antisense oligonucleotides were targeted to the C9orf72 hexanucleotide repeat expansion to upregulate normal variant 1 transcript levels, the defective vesicle trafficking and dysfunctional trans-Golgi network phenotypes were reversed, suggesting that both loss- and gain-of-function mechanisms play a role in disease pathogenesis. In conclusion, we have identified a novel mechanism for C9ALS/FTD pathogenesis highlighting the molecular regulation of intracellular and extracellular vesicle trafficking as an important pathway in C9ALS/FTD pathogenesis.

    Original languageEnglish
    Pages (from-to)887-897
    Number of pages11
    JournalBrain
    Volume140
    Issue number4
    DOIs
    Publication statusPublished - 2017 Apr 1

    Keywords

    • C9ALS/FTD
    • C9orf72
    • RAB7L1
    • extracellular vesicles
    • haploinsufficiency

    ASJC Scopus subject areas

    • Clinical Neurology

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