title: Postsynaptic density protein PSD-95 expression in Alzheimer's disease and okadaic acid induced neuritic retraction.
abstract: In order to understand how plasticity is related to neurodegeneration, we studied synaptic proteins with quantitative immunohistochemistry in the entorhinal cortex from Alzheimer patients and age-matched controls. We observed a significant decrease in presynaptic synaptophysin and an increase in postsynaptic density protein PSD-95, positively correlated with beta amyloid and phosphorylated Tau proteins in Alzheimer cases. Furthermore, Alzheimer-like neuritic retraction was generated in okadaic acid (OA) treated SH-SY5Y neuroblastoma cells with no decrease in PSD-95 expression. However, in a SH-SY5Y clone with decreased expression of transcription regulator LMO4 (as observed in Alzheimer's disease) and increased neuritic length, PSD-95 expression was enhanced but did not change with OA treatment. Therefore, increased PSD-95 immunoreactivity in the entorhinal cortex might result from compensatory mechanisms, as in the SH-SY5Y clone, whereas increased Alzheimer-like Tau phosphorylation is not related to PSD-95 expression, as suggested by the OA-treated cell models.
authors.affiliation: Center for Psychiatric Neuroscience, Department of Psychiatry, CHUV, Lausanne, Switzerland; Service of Old Age Psychiatry, Department of Psychiatry, CHUV, Lausanne, Switzerland.
authors.forename: Geneviève
authors.initials: G
authors.lastname: Leuba
authors.affiliation: Department of Psychiatry, University Hospital Geneva, Geneva, Switzerland.
authors.forename: Claude
authors.initials: C
authors.lastname: Walzer
authors.affiliation: Center for Psychiatric Neuroscience, Department of Psychiatry, CHUV, Lausanne, Switzerland; Service of Old Age Psychiatry, Department of Psychiatry, CHUV, Lausanne, Switzerland.
authors.forename: André
authors.initials: A
authors.lastname: Vernay
authors.affiliation: Center for Psychiatric Neuroscience, Department of Psychiatry, CHUV, Lausanne, Switzerland; Service of Old Age Psychiatry, Department of Psychiatry, CHUV, Lausanne, Switzerland.
authors.forename: Béatrice
authors.initials: B
authors.lastname: Carnal
authors.affiliation: Department of Cell Biology and Morphology, Lausanne University, Lausanne, Switzerland.
authors.forename: Rudolf
authors.initials: R
authors.lastname: Kraftsik
authors.affiliation: Department of Psychiatry, University Hospital Geneva, Geneva, Switzerland.
authors.forename: Françoise
authors.initials: F
authors.lastname: Piotton
authors.affiliation: Department of Psychiatry, University Hospital Geneva, Geneva, Switzerland.
authors.forename: Pascale
authors.initials: P
authors.lastname: Marin
authors.affiliation: Department of Psychiatry, University Hospital Geneva, Geneva, Switzerland.
authors.forename: Constantin
authors.initials: C
authors.lastname: Bouras
authors.affiliation: Department of Psychiatry, University Hospital Geneva, Geneva, Switzerland. Electronic address: armand.savioz@hcuge.ch.
authors.forename: Armand
authors.initials: A
authors.lastname: Savioz
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D016229:Amyloid beta-Peptides / Q000378:metabolism; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D000076122:Disks Large Homolog 4 Protein; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics; D008297:Male; D008565:Membrane Proteins / Q000096:biosynthesis* / Q000235:genetics; D008875:Middle Aged; D016501:Neurites / Q000187:drug effects / Q000473:pathology / Q000502:physiology*; D019319:Okadaic Acid / Q000633:toxicity*; D010766:Phosphorylation; D015854:Up-Regulation / Q000235:genetics; D016875:tau Proteins / Q000378:metabolism
chemical_list: D016229:Amyloid beta-Peptides; C501444:DLG4 protein, human; D000076122:Disks Large Homolog 4 Protein; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D016875:tau Proteins; D019319:Okadaic Acid