title: Plastin 3 is upregulated in iPSC-derived motoneurons from asymptomatic SMN1-deleted individuals.
abstract: Spinal muscular atrophy (SMA) is a devastating motoneuron (MN) disorder caused by homozygous loss of SMN1. Rarely, SMN1-deleted individuals are fully asymptomatic despite carrying identical SMN2 copies as their SMA III-affected siblings suggesting protection by genetic modifiers other than SMN2. High plastin 3 (PLS3) expression has previously been found in lymphoblastoid cells but not in fibroblasts of asymptomatic compared to symptomatic siblings. To find out whether PLS3 is also upregulated in MNs of asymptomatic individuals and thus a convincing SMA protective modifier, we generated induced pluripotent stem cells (iPSCs) from fibroblasts of three asymptomatic and three SMA III-affected siblings from two families and compared these to iPSCs from a SMA I patient and control individuals. MNs were differentiated from iPSC-derived small molecule neural precursor cells (smNPCs). All four genotype classes showed similar capacity to differentiate into MNs at day 8. However, SMA I-derived MN survival was significantly decreased while SMA III- and asymptomatic-derived MN survival was moderately reduced compared to controls at day 27. SMN expression levels and concomitant gem numbers broadly matched SMN2 copy number distribution; SMA I presented the lowest levels, whereas SMA III and asymptomatic showed similar levels. In contrast, PLS3 was significantly upregulated in mixed MN cultures from asymptomatic individuals pinpointing a tissue-specific regulation. Evidence for strong PLS3 accumulation in shaft and rim of growth cones in MN cultures from asymptomatic individuals implies an important role in neuromuscular synapse formation and maintenance. These findings provide strong evidence that PLS3 is a genuine SMA protective modifier.
authors.affiliation: Institute of Human Genetics, Institute of Genetics and Center for Molecular Medicine Cologne, University of Cologne, Kerpener Str. 34, 50931, Cologne, Germany.|Institute of Reconstructive Neurobiology, LIFE & BRAIN Center, University of Bonn, Sigmund-Freud-Str. 25, 53105, Bonn, Germany.
authors.forename: Ludwig
authors.initials: L
authors.lastname: Heesen
authors.affiliation: Institute of Reconstructive Neurobiology, LIFE & BRAIN Center, University of Bonn, Sigmund-Freud-Str. 25, 53105, Bonn, Germany.|DZNE, German Center for Neurodegenerative Diseases, Bonn, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Peitz
authors.affiliation: Institute of Human Genetics, Institute of Genetics and Center for Molecular Medicine Cologne, University of Cologne, Kerpener Str. 34, 50931, Cologne, Germany.
authors.forename: Laura
authors.initials: L
authors.lastname: Torres-Benito
authors.affiliation: Institute of Human Genetics, Institute of Genetics and Center for Molecular Medicine Cologne, University of Cologne, Kerpener Str. 34, 50931, Cologne, Germany.
authors.forename: Irmgard
authors.initials: I
authors.lastname: Hölker
authors.affiliation: Institute of Reconstructive Neurobiology, LIFE & BRAIN Center, University of Bonn, Sigmund-Freud-Str. 25, 53105, Bonn, Germany.
authors.forename: Kristina
authors.initials: K
authors.lastname: Hupperich
authors.affiliation: Institute of Reconstructive Neurobiology, LIFE & BRAIN Center, University of Bonn, Sigmund-Freud-Str. 25, 53105, Bonn, Germany.
authors.forename: Kristina
authors.initials: K
authors.lastname: Dobrindt
authors.affiliation: Institute of Reconstructive Neurobiology, LIFE & BRAIN Center, University of Bonn, Sigmund-Freud-Str. 25, 53105, Bonn, Germany.|DZNE, German Center for Neurodegenerative Diseases, Bonn, Germany.
authors.forename: Johannes
authors.initials: J
authors.lastname: Jungverdorben
authors.affiliation: Institute of Reconstructive Neurobiology, LIFE & BRAIN Center, University of Bonn, Sigmund-Freud-Str. 25, 53105, Bonn, Germany.
authors.forename: Swetlana
authors.initials: S
authors.lastname: Ritzenhofen
authors.affiliation: Institute of Reconstructive Neurobiology, LIFE & BRAIN Center, University of Bonn, Sigmund-Freud-Str. 25, 53105, Bonn, Germany.|DZNE, German Center for Neurodegenerative Diseases, Bonn, Germany.
authors.forename: Beatrice
authors.initials: B
authors.lastname: Weykopf
authors.affiliation: Institute of Reconstructive Neurobiology, LIFE & BRAIN Center, University of Bonn, Sigmund-Freud-Str. 25, 53105, Bonn, Germany.
authors.forename: Daniela
authors.initials: D
authors.lastname: Eckert
authors.affiliation: Institute of Human Genetics, Institute of Genetics and Center for Molecular Medicine Cologne, University of Cologne, Kerpener Str. 34, 50931, Cologne, Germany.
authors.forename: Seyyed Mohsen
authors.initials: SM
authors.lastname: Hosseini-Barkooie
authors.affiliation: Institute of Human Genetics, Institute of Genetics and Center for Molecular Medicine Cologne, University of Cologne, Kerpener Str. 34, 50931, Cologne, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Storbeck
authors.affiliation: Keio University School of Medicine and JST PRESTO, Tokyo, Japan.
authors.forename: Noemi
authors.initials: N
authors.lastname: Fusaki
authors.affiliation: Department of Biological and Medical Sciences, University of Udine, Udine, Italy.|Institute of Clinical Pathology, A. O. U, Udine, Italy.
authors.forename: Renata
authors.initials: R
authors.lastname: Lonigro
authors.affiliation: Institute of Human Genetics, Institute of Genetics and Center for Molecular Medicine Cologne, University of Cologne, Kerpener Str. 34, 50931, Cologne, Germany.
authors.forename: Raoul
authors.initials: R
authors.lastname: Heller
authors.affiliation: Institute of Human Genetics, Institute of Genetics and Center for Molecular Medicine Cologne, University of Cologne, Kerpener Str. 34, 50931, Cologne, Germany.
authors.forename: Min Jeong
authors.initials: MJ
authors.lastname: Kye
authors.affiliation: Institute of Reconstructive Neurobiology, LIFE & BRAIN Center, University of Bonn, Sigmund-Freud-Str. 25, 53105, Bonn, Germany. brustle@uni-bonn.de.|DZNE, German Center for Neurodegenerative Diseases, Bonn, Germany. brustle@uni-bonn.de.
authors.forename: Oliver
authors.initials: O
authors.lastname: Brüstle
authors.affiliation: Institute of Human Genetics, Institute of Genetics and Center for Molecular Medicine Cologne, University of Cologne, Kerpener Str. 34, 50931, Cologne, Germany. brunhilde.wirth@uk-koeln.de.
authors.forename: Brunhilde
authors.initials: B
authors.lastname: Wirth
mesh_terms: D001706:Biopsy; D002454:Cell Differentiation; D005260:Female; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism; D017353:Gene Deletion; D020868:Gene Silencing; D005822:Genetic Vectors; D005838:Genotype; D006801:Humans; D007150:Immunohistochemistry; D057026:Induced Pluripotent Stem Cells / Q000166:cytology; D007621:Karyotyping; D008214:Lymphocytes / Q000166:cytology; D008297:Male; D008562:Membrane Glycoproteins / Q000378:metabolism*; D008840:Microfilament Proteins / Q000378:metabolism*; D018613:Microscopy, Confocal; D009046:Motor Neurons / Q000473:pathology*; D009134:Muscular Atrophy, Spinal / Q000235:genetics*; D009154:Mutation; D058953:Neural Stem Cells / Q000166:cytology*; D010375:Pedigree; D010641:Phenotype; D034741:RNA, Small Interfering / Q000378:metabolism; D012867:Skin / Q000473:pathology; D055533:Survival of Motor Neuron 1 Protein / Q000235:genetics*; D015854:Up-Regulation
chemical_list: D008562:Membrane Glycoproteins; D008840:Microfilament Proteins; D034741:RNA, Small Interfering; C526471:SMN1 protein, human; D055533:Survival of Motor Neuron 1 Protein; C026742:plastin
keywords: F-actin dynamics; Gene expression; Gene modifier; Growth cones; Sendai virus