title: Identification of proteins that are differentially expressed in brains with Alzheimer's disease using iTRAQ labeling and tandem mass spectrometry.
abstract: Alzheimer's disease is one of the leading causes of dementia in the elderly. It is considered the result of complex events involving both genetic and environmental factors. To gain further insights into this complexity, we quantitatively analyzed the proteome of cortex region of brains from patients diagnosed with Alzheimer's disease, using a bottom-up proteomics approach. We identified 721 isobaric-tagged polypeptides. From this universe, 61 were found overexpressed and 69 subexpressed in three brains with Alzheimer's disease in comparison to a normal brain. We determined that the most affected processes involving the overexpressed polypeptides corresponded to ROS and stress responses. For the subexpressed polypeptides, the main processes affected were oxidative phosphorylation, organellar acidification and cytoskeleton. We used Drosophila to validate some of the hits, particularly those non-previously described as connected with the disease, such as Sideroflexin and Phosphoglucomutase-1. We manipulated their homolog genes in Drosophila models of Aβ- and Tau-induced pathology. We found proteins that can either modify Aβ toxicity, Tau toxicity or both, suggesting specific interactions with different pathways. This approach illustrates the potential of Drosophila to validate hits after MS studies and suggest that model organisms should be included in the pipeline to identify relevant targets for Alzheimer's disease.
  
  
  CONCLUSIONS
  We report a set of differentially expressed proteins in three Alzheimer's disease brains in comparison to a normal brain. Our analyses allowed us to identify that the main affected pathways were ROS and stress responses, oxidative phosphorylation, organellar acidification and cytoskeleton. We validated some identified proteins using genetic models of Amyloid-β and Tau-induced pathology in Drosophila melanogaster. With this approach, Sideroflexin and Phosphoglucomutase-1 were identified as novel proteins connected with Alzheimer's disease.
authors.affiliation: Departamento de Biología Celular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (Cinvestav-IPN), Av. Instituto Politécnico Nacional 2508, Col. San Pedro Zacatenco, Gustavo A. Madero, C.P. 07360 Ciudad de México, México. Electronic address: bminjarez@hotmail.com.
authors.forename: Benito
authors.initials: B
authors.lastname: Minjarez
authors.affiliation: Departamento de Biología Celular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (Cinvestav-IPN), Av. Instituto Politécnico Nacional 2508, Col. San Pedro Zacatenco, Gustavo A. Madero, C.P. 07360 Ciudad de México, México. Electronic address: karla_grises@hotmail.com.
authors.forename: Karla Grisel
authors.initials: KG
authors.lastname: Calderón-González
authors.affiliation: Unidad de Proteómica, Centro de Investigación Príncipe Felipe, C/Rambla del Saler 16, 46012 Valencia, España. Electronic address: mluz.valero@uv.es.
authors.forename: Ma Luz Valero
authors.initials: ML
authors.lastname: Rustarazo
authors.affiliation: Departamento de Biología Celular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (Cinvestav-IPN), Av. Instituto Politécnico Nacional 2508, Col. San Pedro Zacatenco, Gustavo A. Madero, C.P. 07360 Ciudad de México, México. Electronic address: maestherha2@yahoo.com.mx.
authors.forename: María Esther
authors.initials: ME
authors.lastname: Herrera-Aguirre
authors.affiliation: Departamento de Biología Celular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (Cinvestav-IPN), Av. Instituto Politécnico Nacional 2508, Col. San Pedro Zacatenco, Gustavo A. Madero, C.P. 07360 Ciudad de México, México. Electronic address: azu_car2000@yahoo.com.mx.
authors.forename: María Luisa
authors.initials: ML
authors.lastname: Labra-Barrios
authors.affiliation: Department of Neurology, McKnight Brain Institute, University of Florida, Gainesville, FL 32611, USA; Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL 32611, USA. Electronic address: diego.rincon@neurology.ufl.edu.
authors.forename: Diego E
authors.initials: DE
authors.lastname: Rincon-Limas
authors.affiliation: Unidad de Proteómica, Centro de Investigación Príncipe Felipe, C/Rambla del Saler 16, 46012 Valencia, España. Electronic address: sandelpi@uv.es.
authors.forename: Manuel M Sánchez
authors.initials: MM
authors.lastname: Del Pino
authors.affiliation: Departamento de Fisiología, Biofísica y Neurociencias, Cinvestav-IPN, Av. Instituto Politécnico Nacional 2508, Col. San Pedro Zacatenco, Gustavo A. Madero, C.P. 07360 Ciudad de México, México.
authors.forename: Raul
authors.initials: R
authors.lastname: Mena
authors.affiliation: Departamento de Biología Celular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (Cinvestav-IPN), Av. Instituto Politécnico Nacional 2508, Col. San Pedro Zacatenco, Gustavo A. Madero, C.P. 07360 Ciudad de México, México. Electronic address: jpluna@cell.cinvestav.mx.
authors.forename: Juan Pedro
authors.initials: JP
authors.lastname: Luna-Arias
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000378:metabolism*; D000818:Animals; D001921:Brain / Q000378:metabolism*; D004195:Disease Models, Animal; D029721:Drosophila Proteins / Q000378:metabolism; D004331:Drosophila melanogaster; D005260:Female; D005786:Gene Expression Regulation; D006801:Humans; D013058:Mass Spectrometry / Q000379:methods*; D009419:Nerve Tissue Proteins / Q000096:biosynthesis*
chemical_list: D029721:Drosophila Proteins; D009419:Nerve Tissue Proteins
keywords: Alzheimer's disease; Amyloid-β and tau; Drosophila; Neurofibrillary tangle; Tandem mass spectrometry; iTRAQ labeling