Transcriptomic analysis of iPSC-derived motor neurons from ALS patients carrying ATXN2 intermediate repeat expansions and healthy controls

Intermediate-length repeat expansions in ATAXIN-2 (ATXN2) are a strong genetic risk factor for amyotrophic lateral sclerosis (ALS). At the molecular level, ATXN2 intermediate expansions enhance TDP-43 toxicity and pathology. However, whether this triggers ALS pathogenesis at the cellular and functional level remains unknown. Here, we developed a human iPSC-derived model to investigate whether motor neurons derived from ALS patients carrying ATXN2 intermediate repeat expansions are transcriptomically distinct from healthy controls. For that, we performed RNA sequencing of motor neurons derived from 5 ATXN2-ALS iPSC lines and 5 healthy controls (HC). iPSC differentiation into MN was performed as described previously with minor modifications (Amoroso et al., 2013). Human iPSC-derived MN samples from 5 controls and 5 ATXN2-ALS lines were isolated after 12 days of co-culture with mouse primary glia. Total RNA was isolated and extracted using the RNeasy Micro Kit and only samples with RIN ≥ 8.0 were used for RNA sequencing.