title: Neurocalcin Delta Suppression Protects against Spinal Muscular Atrophy in Humans and across Species by Restoring Impaired Endocytosis.
abstract: Homozygous SMN1 loss causes spinal muscular atrophy (SMA), the most common lethal genetic childhood motor neuron disease. SMN1 encodes SMN, a ubiquitous housekeeping protein, which makes the primarily motor neuron-specific phenotype rather unexpected. SMA-affected individuals harbor low SMN expression from one to six SMN2 copies, which is insufficient to functionally compensate for SMN1 loss. However, rarely individuals with homozygous absence of SMN1 and only three to four SMN2 copies are fully asymptomatic, suggesting protection through genetic modifier(s). Previously, we identified plastin 3 (PLS3) overexpression as an SMA protective modifier in humans and showed that SMN deficit impairs endocytosis, which is rescued by elevated PLS3 levels. Here, we identify reduction of the neuronal calcium sensor Neurocalcin delta (NCALD) as a protective SMA modifier in five asymptomatic SMN1-deleted individuals carrying only four SMN2 copies. We demonstrate that NCALD is a Ca2+-dependent negative regulator of endocytosis, as NCALD knockdown improves endocytosis in SMA models and ameliorates pharmacologically induced endocytosis defects in zebrafish. Importantly, NCALD knockdown effectively ameliorates SMA-associated pathological defects across species, including worm, zebrafish, and mouse. In conclusion, our study identifies a previously unknown protective SMA modifier in humans, demonstrates modifier impact in three different SMA animal models, and suggests a potential combinatorial therapeutic strategy to efficiently treat SMA. Since both protective modifiers restore endocytosis, our results confirm that endocytosis is a major cellular mechanism perturbed in SMA and emphasize the power of protective modifiers for understanding disease mechanism and developing therapies.
authors.affiliation: Institute of Human Genetics, University of Cologne, 50931 Cologne, Germany; Center for Molecular Medicine Cologne, University of Cologne, 50931 Cologne, Germany; Institute for Genetics, University of Cologne, 50674 Cologne, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Riessland
authors.affiliation: Institute of Human Genetics, University of Cologne, 50931 Cologne, Germany; Center for Molecular Medicine Cologne, University of Cologne, 50931 Cologne, Germany; Institute for Genetics, University of Cologne, 50674 Cologne, Germany.
authors.forename: Anna
authors.initials: A
authors.lastname: Kaczmarek
authors.affiliation: Institute of Human Genetics, University of Cologne, 50931 Cologne, Germany; Center for Molecular Medicine Cologne, University of Cologne, 50931 Cologne, Germany; Institute for Genetics, University of Cologne, 50674 Cologne, Germany.
authors.forename: Svenja
authors.initials: S
authors.lastname: Schneider
authors.affiliation: MassGeneral Hospital for Children, Boston, MA 02115, USA.
authors.forename: Kathryn J
authors.initials: KJ
authors.lastname: Swoboda
authors.affiliation: Institute for Zoology - Developmental Biology, University of Cologne, 50674 Cologne, Germany; Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD), University of Cologne, 50931 Cologne, Germany.
authors.forename: Heiko
authors.initials: H
authors.lastname: Löhr
authors.affiliation: Institute for Zoology - Neurophysiology University of Cologne, 50674 Cologne, Germany; Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD), University of Cologne, 50931 Cologne, Germany.
authors.forename: Cathleen
authors.initials: C
authors.lastname: Bradler
authors.affiliation: Institute of Human Genetics, University of Cologne, 50931 Cologne, Germany; Center for Molecular Medicine Cologne, University of Cologne, 50931 Cologne, Germany; Institute for Genetics, University of Cologne, 50674 Cologne, Germany.
authors.forename: Vanessa
authors.initials: V
authors.lastname: Grysko
authors.affiliation: Department of Neuroscience, Brown University, Providence, RI 02912, USA.
authors.forename: Maria
authors.initials: M
authors.lastname: Dimitriadi
authors.affiliation: Institute of Human Genetics, University of Cologne, 50931 Cologne, Germany; Center for Molecular Medicine Cologne, University of Cologne, 50931 Cologne, Germany; Institute for Genetics, University of Cologne, 50674 Cologne, Germany.
authors.forename: Seyyedmohsen
authors.initials: S
authors.lastname: Hosseinibarkooie
authors.affiliation: Institute of Human Genetics, University of Cologne, 50931 Cologne, Germany; Center for Molecular Medicine Cologne, University of Cologne, 50931 Cologne, Germany; Institute for Genetics, University of Cologne, 50674 Cologne, Germany.
authors.forename: Laura
authors.initials: L
authors.lastname: Torres-Benito
authors.affiliation: Institute of Human Genetics, University of Cologne, 50931 Cologne, Germany; Center for Molecular Medicine Cologne, University of Cologne, 50931 Cologne, Germany; Institute for Genetics, University of Cologne, 50674 Cologne, Germany.
authors.forename: Miriam
authors.initials: M
authors.lastname: Peters
authors.affiliation: Institute of Human Genetics, University of Cologne, 50931 Cologne, Germany; Center for Molecular Medicine Cologne, University of Cologne, 50931 Cologne, Germany; Institute for Genetics, University of Cologne, 50674 Cologne, Germany.
authors.forename: Aaradhita
authors.initials: A
authors.lastname: Upadhyay
authors.affiliation: Institute of Human Genetics, University of Cologne, 50931 Cologne, Germany; Center for Molecular Medicine Cologne, University of Cologne, 50931 Cologne, Germany; Institute for Genetics, University of Cologne, 50674 Cologne, Germany.
authors.forename: Nasim
authors.initials: N
authors.lastname: Biglari
authors.affiliation: Institute of Human Genetics, University of Cologne, 50931 Cologne, Germany; Center for Molecular Medicine Cologne, University of Cologne, 50931 Cologne, Germany; Institute for Genetics, University of Cologne, 50674 Cologne, Germany.
authors.forename: Sandra
authors.initials: S
authors.lastname: Kröber
authors.affiliation: Institute of Human Genetics, University of Cologne, 50931 Cologne, Germany; Center for Molecular Medicine Cologne, University of Cologne, 50931 Cologne, Germany; Institute for Genetics, University of Cologne, 50674 Cologne, Germany.
authors.forename: Irmgard
authors.initials: I
authors.lastname: Hölker
authors.affiliation: Institute of Human Genetics, University of Cologne, 50931 Cologne, Germany; Center for Molecular Medicine Cologne, University of Cologne, 50931 Cologne, Germany; Institute for Genetics, University of Cologne, 50674 Cologne, Germany.
authors.forename: Lutz
authors.initials: L
authors.lastname: Garbes
authors.affiliation: Department of Human Genetics, Donders Centre for Neuroscience, Radboud University Medical Center, 6525 Nijmegen, the Netherlands.
authors.forename: Christian
authors.initials: C
authors.lastname: Gilissen
authors.affiliation: Department of Human Genetics, Donders Centre for Neuroscience, Radboud University Medical Center, 6525 Nijmegen, the Netherlands.
authors.forename: Alexander
authors.initials: A
authors.lastname: Hoischen
authors.affiliation: Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD), University of Cologne, 50931 Cologne, Germany; Center for Genomics Cologne, University of Cologne, 50931 Cologne, Germany.
authors.forename: Gudrun
authors.initials: G
authors.lastname: Nürnberg
authors.affiliation: Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD), University of Cologne, 50931 Cologne, Germany; Center for Genomics Cologne, University of Cologne, 50931 Cologne, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Nürnberg
authors.affiliation: Institute of Medical Genetics, University of Tübingen, 72076 Tübingen, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Walter
authors.affiliation: IONIS Pharmaceuticals, Carlsbad, CA 92008, USA.
authors.forename: Frank
authors.initials: F
authors.lastname: Rigo
authors.affiliation: IONIS Pharmaceuticals, Carlsbad, CA 92008, USA.
authors.forename: C Frank
authors.initials: CF
authors.lastname: Bennett
authors.affiliation: Institute of Human Genetics, University of Cologne, 50931 Cologne, Germany; Center for Molecular Medicine Cologne, University of Cologne, 50931 Cologne, Germany.
authors.forename: Min Jeong
authors.initials: MJ
authors.lastname: Kye
authors.affiliation: Department of Neuroscience, Brown University, Providence, RI 02912, USA.
authors.forename: Anne C
authors.initials: AC
authors.lastname: Hart
authors.affiliation: Center for Molecular Medicine Cologne, University of Cologne, 50931 Cologne, Germany; Institute for Zoology - Developmental Biology, University of Cologne, 50674 Cologne, Germany; Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD), University of Cologne, 50931 Cologne, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Hammerschmidt
authors.affiliation: Institute for Zoology - Neurophysiology University of Cologne, 50674 Cologne, Germany; Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD), University of Cologne, 50931 Cologne, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Kloppenburg
authors.affiliation: Institute of Human Genetics, University of Cologne, 50931 Cologne, Germany; Center for Molecular Medicine Cologne, University of Cologne, 50931 Cologne, Germany; Institute for Genetics, University of Cologne, 50674 Cologne, Germany. Electronic address: brunhilde.wirth@uk-koeln.de.
authors.forename: Brunhilde
authors.initials: B
authors.lastname: Wirth
mesh_terms: D000818:Animals; D017173:Caenorhabditis elegans / Q000235:genetics; D002460:Cell Line; D003001:Cloning, Molecular; D004195:Disease Models, Animal; D004705:Endocytosis / Q000235:genetics*; D005260:Female; D005786:Gene Expression Regulation; D056426:Genetic Loci; D055106:Genome-Wide Association Study; D006720:Homozygote; D006801:Humans; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009046:Motor Neurons / Q000473:pathology; D009134:Muscular Atrophy, Spinal / Q000235:genetics* / Q000628:therapy; D051596:Neurocalcin / Q000235:genetics / Q000378:metabolism*; D016716:PC12 Cells; D010375:Pedigree; D051381:Rats; D055533:Survival of Motor Neuron 1 Protein / Q000235:genetics / Q000378:metabolism; D055540:Survival of Motor Neuron 2 Protein / Q000235:genetics / Q000378:metabolism; D059467:Transcriptome; D015027:Zebrafish / Q000235:genetics
chemical_list: C496685:NCALD protein, human; D051596:Neurocalcin; C526471:SMN1 protein, human; C526477:SMN2 protein, human; D055533:Survival of Motor Neuron 1 Protein; D055540:Survival of Motor Neuron 2 Protein
keywords: NCALD; PLS3; SMA; SMN1; SMN2; asymptomatic; endocytosis; genetic modifier; incomplete penetrance; neuronal sensor protein; spinal muscular dystrophy