title: Longitudinal study of differential protein expression in an Alzheimer's mouse model lacking inducible nitric oxide synthase.
abstract: Alzheimer's disease (AD) is a complex neurodegenerative process that involves altered brain immune, neuronal and metabolic functions. Understanding the underlying mechanisms has relied on mouse models that mimic components of AD pathology. We used gel-free, label-free LC-MS/MS to quantify protein and phosphopeptide levels in brains of APPSwDI/NOS2-/- (CVN-AD) mice. CVN-AD mice show a full spectrum of AD-like pathology, including amyloid deposition, hyperphosphorylated and aggregated tau, and neuronal loss that worsens with age. Tryptic digests, with or without phosphopeptide enrichment on an automated titanium dioxide LC system, were separated by online two-dimensional LC and analyzed on a Waters Synapt G2 HDMS, yielding relative expression for >950 proteins and >1100 phosphopeptides. Among differentially expressed proteins were known markers found in humans with AD, including GFAP and C1Q. Phosphorylation of connexin 43, not previously described in AD, was increased at 42 weeks, consistent with dysregulation of gap junctions and activation of astrocytes. Additional alterations in phosphoproteins suggests dysregulation of mitochondria, synaptic transmission, vesicle trafficking, and innate immune pathways. These data validate the CVN-AD mouse model of AD, identify novel disease and age-related changes in the brain during disease progression, and demonstrate the utility of integrating unbiased and phosphoproteomics for understanding disease processes in AD.
authors.affiliation: Department of Medicine/Neurology, ‡Institute for Genome Sciences & Policy, School of Medicine, and §Division of Pulmonary, Allergy and Critical Care Medicine, Duke University Medical Center, Duke University , Durham, North Carolina 27710, United States.
authors.forename: Michael D
authors.initials: MD
authors.lastname: Hoos
authors.forename: Brenna M
authors.initials: BM
authors.lastname: Richardson
authors.forename: Matthew W
authors.initials: MW
authors.lastname: Foster
authors.forename: Angela
authors.initials: A
authors.lastname: Everhart
authors.forename: J Will
authors.initials: JW
authors.lastname: Thompson
authors.forename: M Arthur
authors.initials: MA
authors.lastname: Moseley
authors.forename: Carol A
authors.initials: CA
authors.lastname: Colton
mesh_terms: D000544:Alzheimer Disease / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D001921:Brain / Q000378:metabolism; D002852:Chromatography, Ion Exchange; D056148:Chromatography, Reverse-Phase; D006801:Humans; D008137:Longitudinal Studies; D008562:Membrane Glycoproteins / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008969:Molecular Sequence Data; D052247:Nitric Oxide Synthase Type II / Q000172:deficiency / Q000235:genetics*; D010748:Phosphopeptides / Q000302:isolation & purification / Q000378:metabolism*; D010766:Phosphorylation; D014176:Protein Biosynthesis; D011499:Protein Processing, Post-Translational; D020543:Proteome / Q000302:isolation & purification / Q000378:metabolism; D011951:Receptors, Complement / Q000378:metabolism; D053719:Tandem Mass Spectrometry; D016875:tau Proteins / Q000378:metabolism
chemical_list: D008562:Membrane Glycoproteins; D010748:Phosphopeptides; D020543:Proteome; D011951:Receptors, Complement; C032402:complement 1q receptor; D016875:tau Proteins; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse