title: In vivo kinetic approach reveals slow SOD1 turnover in the CNS.
abstract: Therapeutic strategies that target disease-associated transcripts are being developed for a variety of neurodegenerative syndromes. Protein levels change as a function of their half-life, a property that critically influences the timing and application of therapeutics. In addition, both protein kinetics and concentration may play important roles in neurodegeneration; therefore, it is essential to understand in vivo protein kinetics, including half-life. Here, we applied a stable isotope-labeling technique in combination with mass spectrometric detection and determined the in vivo kinetics of superoxide dismutase 1 (SOD1), mutation of which causes amyotrophic lateral sclerosis. Application of this method to human SOD1-expressing rats demonstrated that SOD1 is a long-lived protein, with a similar half-life in both the cerebral spinal fluid (CSF) and the CNS. Additionally, in these animals, the half-life of SOD1 was longest in the CNS when compared with other tissues. Evaluation of this method in human subjects demonstrated successful incorporation of the isotope label in the CSF and confirmed that SOD1 is a long-lived protein in the CSF of healthy individuals. Together, the results of this study provide important insight into SOD1 kinetics and support application of this technique to the design and implementation of clinical trials that target long-lived CNS proteins.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Crisp
authors.forename: Kwasi G
authors.initials: KG
authors.lastname: Mawuenyega
authors.forename: Bruce W
authors.initials: BW
authors.lastname: Patterson
authors.forename: Naveen C
authors.initials: NC
authors.lastname: Reddy
authors.forename: Robert
authors.initials: R
authors.lastname: Chott
authors.forename: Wade K
authors.initials: WK
authors.lastname: Self
authors.forename: Conrad C
authors.initials: CC
authors.lastname: Weihl
authors.forename: Jennifer
authors.initials: J
authors.lastname: Jockel-Balsarotti
authors.forename: Arun S
authors.initials: AS
authors.lastname: Varadhachary
authors.forename: Robert C
authors.initials: RC
authors.lastname: Bucelli
authors.forename: Kevin E
authors.initials: KE
authors.lastname: Yarasheski
authors.forename: Randall J
authors.initials: RJ
authors.lastname: Bateman
authors.forename: Timothy M
authors.initials: TM
authors.lastname: Miller
mesh_terms: D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000690:Amyotrophic Lateral Sclerosis / Q000134:cerebrospinal fluid / Q000201:enzymology / Q000235:genetics; D000818:Animals; D002247:Carbon Isotopes; D002490:Central Nervous System / Q000201:enzymology*; D004195:Disease Models, Animal; D005260:Female; D057809:HEK293 Cells; D006801:Humans; D007553:Isotope Labeling; D007700:Kinetics; D008297:Male; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D050505:Mutant Proteins / Q000134:cerebrospinal fluid / Q000235:genetics / Q000378:metabolism; D051381:Rats; D055647:Rats, Transgenic; D011994:Recombinant Proteins / Q000134:cerebrospinal fluid / Q000235:genetics / Q000378:metabolism; D013482:Superoxide Dismutase / Q000134:cerebrospinal fluid / Q000235:genetics / Q000378:metabolism*; D000072105:Superoxide Dismutase-1; D053719:Tandem Mass Spectrometry
chemical_list: D002247:Carbon Isotopes; D050505:Mutant Proteins; D011994:Recombinant Proteins; C000606290:SOD1 protein, human; C000606292:Sod1 protein, rat; D013482:Superoxide Dismutase; D000072105:Superoxide Dismutase-1