HNRNPA2B1 regulates alternative RNA processing in the nervous system and accumulates in granules in ALS IPSC-derived motor neurons [hnRNPA2B1_Arrays_human_iPSC_MN_Stress]

HnRNPA2B1 encodes an RNA binding protein associated with neurodegenerative disorders. However, its function in the nervous system is unclear. Transcriptome-wide cross-linking and immunoprecipitation in mouse spinal cord discover UAGG motifs enriched within ~2,500 hnRNP A2/B1 binding sites and an unexpected role for hnRNP A2/B1 in alternative polyadenylation. Loss of hnRNP A2/B1 results in alternative splicing, including skipping of an exon in amyotrophic lateral sclerosis (ALS)-associated D-amino acid oxidase (DAO) that reduces D-serine metabolism. Inclusion of the DAO exon is also reduced in transgenic ALS mice models. ALS-associated hnRNP A2/B1 D290V mutant patient fibroblasts and motor neurons differentiated from induced pluripotent stem cells demonstrate gain-of-mutant-dependent splicing differences. Mutant motor neurons also exhibit increased hnRNP A2/B1 localization to cytoplasmic granules during stress, which are abrogated by a small molecule CA43. Our findings and cellular resource identify RNA networks affected in loss of normal and mutated hnRNP A2/B1 with broad relevance to neurodegeneration.

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Martinez FJ, Pratt GA, Van Nostrand EL, Batra R, Huelga SC, Kapeli K, Freese P, Chun SJ, Ling K, Gelboin-Burkhart C, Fijany L, Wang HC, Nussbacher JK, Broski SM, Kim HJ, Lardelli R, Sundararaman B, Donohue JP, Javaherian A, Lykke-Andersen J, Finkbeiner S, Bennett CF, Ares M Jr, Burge CB, Taylor JP, Rigo F, Yeo GW