title: Discovery of a biomarker and lead small molecules to target r(GGGGCC)-associated defects in c9FTD/ALS.
abstract: A repeat expansion in C9ORF72 causes frontotemporal dementia and amyotrophic lateral sclerosis (c9FTD/ALS). RNA of the expanded repeat (r(GGGGCC)exp) forms nuclear foci or undergoes repeat-associated non-ATG (RAN) translation, producing "c9RAN proteins." Since neutralizing r(GGGGCC)exp could inhibit these potentially toxic events, we sought to identify small-molecule binders of r(GGGGCC)exp. Chemical and enzymatic probing of r(GGGGCC)8 indicate that it adopts a hairpin structure in equilibrium with a quadruplex structure. Using this model, bioactive small molecules targeting r(GGGGCC)exp were designed and found to significantly inhibit RAN translation and foci formation in cultured cells expressing r(GGGGCC)66 and neurons transdifferentiated from fibroblasts of repeat expansion carriers. Finally, we show that poly(GP) c9RAN proteins are specifically detected in c9ALS patient cerebrospinal fluid. Our findings highlight r(GGGGCC)exp-binding small molecules as a possible c9FTD/ALS therapeutic and suggest that c9RAN proteins could potentially serve as a pharmacodynamic biomarker to assess efficacy of therapies that target r(GGGGCC)exp.
authors.affiliation: Department of Chemistry, The Scripps Research Institute, Scripps Florida, 130 Scripps Way #3A1, Jupiter, FL 33458, USA.
authors.forename: Zhaoming
authors.initials: Z
authors.lastname: Su
authors.affiliation: Department of Neuroscience, Mayo Clinic, 4500 San Pablo Rd., Jacksonville, FL 32224, USA.
authors.forename: Yongjie
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Neuroscience, Mayo Clinic, 4500 San Pablo Rd., Jacksonville, FL 32224, USA.
authors.forename: Tania F
authors.initials: TF
authors.lastname: Gendron
authors.affiliation: Department of Neuroscience, Mayo Clinic, 4500 San Pablo Rd., Jacksonville, FL 32224, USA.
authors.forename: Peter O
authors.initials: PO
authors.lastname: Bauer
authors.affiliation: Department of Neuroscience, Mayo Clinic, 4500 San Pablo Rd., Jacksonville, FL 32224, USA.
authors.forename: Jeannie
authors.initials: J
authors.lastname: Chew
authors.affiliation: Department of Chemistry, The Scripps Research Institute, Scripps Florida, 130 Scripps Way #3A1, Jupiter, FL 33458, USA.
authors.forename: Wang-Yong
authors.initials: WY
authors.lastname: Yang
authors.affiliation: Department of Chemistry, The Scripps Research Institute, Scripps Florida, 130 Scripps Way #3A1, Jupiter, FL 33458, USA.
authors.forename: Erik
authors.initials: E
authors.lastname: Fostvedt
authors.affiliation: Department of Neuroscience, Mayo Clinic, 4500 San Pablo Rd., Jacksonville, FL 32224, USA.
authors.forename: Karen
authors.initials: K
authors.lastname: Jansen-West
authors.affiliation: Department of Neuroscience, Mayo Clinic, 4500 San Pablo Rd., Jacksonville, FL 32224, USA.
authors.forename: Veronique V
authors.initials: VV
authors.lastname: Belzil
authors.affiliation: Department of Neurology, Mayo Clinic, 4500 San Pablo Rd., Jacksonville, FL 32224, USA.
authors.forename: Pamela
authors.initials: P
authors.lastname: Desaro
authors.affiliation: Department of Neurology, Mayo Clinic, 4500 San Pablo Rd., Jacksonville, FL 32224, USA.
authors.forename: Amelia
authors.initials: A
authors.lastname: Johnston
authors.affiliation: Department of Neurology, Mayo Clinic, 4500 San Pablo Rd., Jacksonville, FL 32224, USA.
authors.forename: Karen
authors.initials: K
authors.lastname: Overstreet
authors.affiliation: Department of Neurology, University of Michigan, 1500 E. Medical Center Drive, Ann Arbor, MI 48109, USA.
authors.forename: Seok-Yoon
authors.initials: SY
authors.lastname: Oh
authors.affiliation: Department of Neurology, University of Michigan, 1500 E. Medical Center Drive, Ann Arbor, MI 48109, USA.
authors.forename: Peter K
authors.initials: PK
authors.lastname: Todd
authors.affiliation: Department of Neurology, Massachusetts General Hospital, Harvard Medical School, 15 Parkman Street, Boston, MA 02115, USA.
authors.forename: James D
authors.initials: JD
authors.lastname: Berry
authors.affiliation: Department of Neurology, Massachusetts General Hospital, Harvard Medical School, 15 Parkman Street, Boston, MA 02115, USA.
authors.forename: Merit E
authors.initials: ME
authors.lastname: Cudkowicz
authors.affiliation: Department of Neurology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA.
authors.forename: Bradley F
authors.initials: BF
authors.lastname: Boeve
authors.affiliation: Department of Neuroscience, Mayo Clinic, 4500 San Pablo Rd., Jacksonville, FL 32224, USA.
authors.forename: Dennis
authors.initials: D
authors.lastname: Dickson
authors.affiliation: Spasticity and Spinal Physiology Unit, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: Mary Kay
authors.initials: MK
authors.lastname: Floeter
authors.affiliation: Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: Bryan J
authors.initials: BJ
authors.lastname: Traynor
authors.affiliation: Department of Neurology and Laboratory of Neuroscience, IRCCS Istituto Auxologico Italiano, Via Zucchi, 18, 20095 Cusano Milanino (Milan), Italy.
authors.forename: Claudia
authors.initials: C
authors.lastname: Morelli
authors.affiliation: Department of Neurology and Laboratory of Neuroscience, IRCCS Istituto Auxologico Italiano, Via Zucchi, 18, 20095 Cusano Milanino (Milan), Italy; Department of Pathophysiology and Transplantation, "Dino Ferrari" Center, Università degli Studi di Milano, Via Sforza, 35, 20122, Milan, Italy.
authors.forename: Antonia
authors.initials: A
authors.lastname: Ratti
authors.affiliation: Department of Pathophysiology and Transplantation, "Dino Ferrari" Center, Università degli Studi di Milano, Via Sforza, 35, 20122, Milan, Italy; Department of Neurology, University of Massachusetts Medical School, Worcester, MA 01655, USA.
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Silani
authors.affiliation: Department of Neuroscience, Mayo Clinic, 4500 San Pablo Rd., Jacksonville, FL 32224, USA.
authors.forename: Rosa
authors.initials: R
authors.lastname: Rademakers
authors.affiliation: Department of Neurology, University of Massachusetts Medical School, Worcester, MA 01655, USA.
authors.forename: Robert H
authors.initials: RH
authors.lastname: Brown
authors.affiliation: Department of Neurology, Brain Science Institute, Johns Hopkins University, 855 N Wolfe Street, Baltimore, MD 21205, USA.
authors.forename: Jeffrey D
authors.initials: JD
authors.lastname: Rothstein
authors.affiliation: Department of Neurology, Mayo Clinic, 4500 San Pablo Rd., Jacksonville, FL 32224, USA.
authors.forename: Kevin B
authors.initials: KB
authors.lastname: Boylan
authors.affiliation: Department of Neuroscience, Mayo Clinic, 4500 San Pablo Rd., Jacksonville, FL 32224, USA. Electronic address: petrucelli.leonard@mayo.edu.
authors.forename: Leonard
authors.initials: L
authors.lastname: Petrucelli
authors.affiliation: Department of Chemistry, The Scripps Research Institute, Scripps Florida, 130 Scripps Way #3A1, Jupiter, FL 33458, USA. Electronic address: disney@scripps.edu.
authors.forename: Matthew D
authors.initials: MD
authors.lastname: Disney
mesh_terms: D000328:Adult; D000368:Aged; D000690:Amyotrophic Lateral Sclerosis / Q000134:cerebrospinal fluid / Q000235:genetics* / Q000378:metabolism* / Q000473:pathology; D000818:Animals; D015415:Biomarkers / Q000032:analysis*; D000073885:C9orf72 Protein; D002454:Cell Differentiation / Q000187:drug effects / Q000235:genetics; D002478:Cells, Cultured; D002522:Chlorocebus aethiops; D042622:DNA Repeat Expansion / Q000235:genetics*; D005260:Female; D005347:Fibroblasts; D054856:G-Quadruplexes; D006801:Humans; D008297:Male; D008875:Middle Aged; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009474:Neurons / Q000378:metabolism; D011485:Protein Binding; D011506:Proteins / Q000737:chemistry / Q000235:genetics*; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism
chemical_list: D015415:Biomarkers; D000073885:C9orf72 Protein; C568651:C9orf72 protein, human; D009419:Nerve Tissue Proteins; D011506:Proteins; D034741:RNA, Small Interfering