FUS-ALS hiPSC-derived astrocytes impair human motor units through both gain-of-toxicity and loss-of-support mechanisms.

"Declarations Ethics approval and consent to participateWritten informed consent was obtained from all subjects who provided tissue samples. The use of patient fibroblasts for the generation of hiPSCs was approved by the ethics committee of University Hospital Leuven (n° S50354 and S63792), while the use of myoblasts was approved by the ethical commission (n° NH019-2020–04-02). Consent for publicationNot applicable. Competing interestsThe authors declare that they have no competing interests. Competing interests The authors declare that they have no competing interests."

"Funding This research was supported by the VIB, KU Leuven (C1 and “Opening the Future” Fund), the Agency for Innovation by Science and Technology (IWT; SBO-iPSCAF), the “Fund for Scientific Research Flanders” (FWO-Vlaanderen), Target ALS, the ALS Liga België (A Cure for ALS), the Belgian Government (Interuniversity Attraction Poles Program P7/16 initiated by the Belgian Federal Science Policy Office), the Thierry Latran Foundation and the “Association Belge contre les Maladies neuro-Musculaires” (ABMM). P.V.D holds a senior clinical investigatorship of FWO-Vlaanderen and is supported by the E. von Behring Chair for Neuromuscular and Neurodegenerative Disorders, the ALS Liga België and the KU Leuven funds “Een Hart voor ALS”, “Laeversfonds voor ALS Onderzoek” and the “Valéry Perrier Race against ALS Fund”. L.Te. is funded by an FWO mandate (1133520N) and L.Th. receives support via FWO (G0D3620N) and KU Leuven (C24E/20/067)."