title: FUS Mislocalization and Vulnerability to DNA Damage in ALS Patients Derived hiPSCs and Aging Motoneurons.
abstract: Mutations within theFUSgene (Fused in Sarcoma) are known to cause Amyotrophic Lateral Sclerosis (ALS), a neurodegenerative disease affecting upper and lower motoneurons. TheFUSgene codes for a multifunctional RNA/DNA-binding protein that is primarily localized in the nucleus and is involved in cellular processes such as splicing, translation, mRNA transport and DNA damage response. In this study, we analyzed pathophysiological alterations associated with ALS related FUS mutations (mFUS) in human induced pluripotent stem cells (hiPSCs) and hiPSC derived motoneurons. To that end, we compared cells carrying a mild or severe mFUS in physiological- and/or stress conditions as well as after induced DNA damage. Following hyperosmolar stress or irradiation, mFUS hiPS cells recruited significantly more cytoplasmatic FUS into stress granules accompanied by impaired DNA-damage repair. In motoneurons wild-type FUS was localized in the nucleus but also deposited as small punctae within neurites. In motoneurons expressing mFUS the protein was additionally detected in the cytoplasm and a significantly increased number of large, densely packed FUS positive stress granules were seen along neurites. The amount of FUS mislocalization correlated positively with both the onset of the human disease (the earlier the onset the higher the FUS mislocalization) and the maturation status of the motoneurons. Moreover, even in non-stressed post-mitotic mFUS motoneurons clear signs of DNA-damage could be detected. In summary, we found that the susceptibility to cell stress was higher in mFUS hiPSCs and hiPSC derived motoneurons than in controls and the degree of FUS mislocalization correlated well with the clinical severity of the underlying ALS related mFUS. The accumulation of DNA damage and the cellular response to DNA damage stressors was more pronounced in post-mitotic mFUS motoneurons than in dividing hiPSCs suggesting that mFUS motoneurons accumulate foci of DNA damage, which in turn might be directly linked to neurodegeneration.
authors.affiliation: Institute for Anatomy and Cell Biology, Ulm University Ulm, Germany.
authors.forename: Julia
authors.initials: J
authors.lastname: Higelin
authors.affiliation: Institute for Anatomy and Cell Biology, Ulm University Ulm, Germany.
authors.forename: Maria
authors.initials: M
authors.lastname: Demestre
authors.affiliation: Institute for Anatomy and Cell Biology, Ulm UniversityUlm, Germany; Department of Neurology, Ulm UniversityUlm, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Putz
authors.affiliation: Institute for Anatomy and Cell Biology, Ulm University Ulm, Germany.
authors.forename: Jan P
authors.initials: JP
authors.lastname: Delling
authors.affiliation: Institute for Anatomy and Cell Biology, Ulm University Ulm, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Jacob
authors.affiliation: Institute for Anatomy and Cell Biology, Ulm University Ulm, Germany.
authors.forename: Anne-Kathrin
authors.initials: AK
authors.lastname: Lutz
authors.affiliation: Institute for Human Genetics, Ulm University Ulm, Germany.
authors.forename: Julia
authors.initials: J
authors.lastname: Bausinger
authors.affiliation: Institute for Anatomy and Cell Biology, Ulm University Ulm, Germany.
authors.forename: Anne-Kathrin
authors.initials: AK
authors.lastname: Huber
authors.affiliation: Institute of Neuroanatomy, Eberhard Karls University of Tübingen Tübingen, Germany.
authors.forename: Moritz
authors.initials: M
authors.lastname: Klingenstein
authors.affiliation: Institute for Human Genetics, Ulm University Ulm, Germany.
authors.forename: Gotthold
authors.initials: G
authors.lastname: Barbi
authors.affiliation: Institute for Human Genetics, Ulm University Ulm, Germany.
authors.forename: Günter
authors.initials: G
authors.lastname: Speit
authors.affiliation: Department of Neurology, Ulm University Ulm, Germany.
authors.forename: Annemarie
authors.initials: A
authors.lastname: Huebers
authors.affiliation: Department of Neurology, Ulm University Ulm, Germany.
authors.forename: Jochen H
authors.initials: JH
authors.lastname: Weishaupt
authors.affiliation: Department of Neurology, Technische Universität DresdenDresden, Germany; German Center for Neurodegenerative DiseasesDresden, Germany; Center for Regenerative Therapies Dresden, Technische Universität DresdenDresden, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Hermann
authors.affiliation: Institute of Neuroanatomy, Eberhard Karls University of Tübingen Tübingen, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Liebau
authors.affiliation: Department of Neurology, Ulm University Ulm, Germany.
authors.forename: Albert C
authors.initials: AC
authors.lastname: Ludolph
authors.affiliation: Institute for Anatomy and Cell Biology, Ulm University Ulm, Germany.
authors.forename: Tobias M
authors.initials: TM
authors.lastname: Boeckers
keywords: ALS; DNA damage; FTLD; FUS; hiPSC; motoneuron; neurodegeneration