title: Early changes in hippocampal Eph receptors precede the onset of memory decline in mouse models of Alzheimer's disease.
abstract: Synapse loss occurs early in Alzheimer's disease (AD) and is considered the best pathological correlate of cognitive decline. Ephrins and Eph receptors are involved in regulation of excitatory neurotransmission and play a role in cytoskeleton remodeling. We asked whether alterations in Eph receptors could underlie cognitive impairment in an AD mouse model overexpressing human amyloid-beta protein precursor (hA beta PP) with familial mutations (hA beta PP swe-ind mice). We found that EphA4 and EphB2 receptors were reduced in the hippocampus before the development of impaired object recognition and spatial memory. Similar results were obtained in another line of transgenic A beta PP mice, Tg2576. A reduction in Eph receptor levels was also found in postmortem hippocampal tissue from patients with incipient AD. At the time of onset of memory decline inhA beta PP swe-ind mice, no change in surface expression of AMPA or NMDA receptor subunits was apparent, but we found changes in Eph-receptor downstream signaling, in particular a decrease in membrane-associated phosho-cofilin levels that may cause cytoskeletal changes and disrupted synaptic activity. Consistent with this finding, Eph receptor activation in cell culture increased phosho-cofilin levels. The results suggest that alterations in Eph receptors may play a role in synaptic dysfunction in the hippocampus leading to cognitive impairment in a model of AD.
authors: Division of Neurosciences, CIMA, University of Navarra, Pamplona, Spain CIBERNED, Spain.
authors: Ana María
authors: AM
authors: Simón
authors: Rakel López
authors: RL
authors: de Maturana
authors: Ana
authors: A
authors: Ricobaraza
authors: Luis
authors: L
authors: Escribano
authors: Lucio
authors: L
authors: Schiapparelli
authors: Mar
authors: M
authors: Cuadrado-Tejedor
authors: Alberto
authors: A
authors: Pérez-Mediavilla
authors: Jesús
authors: J
authors: Avila
authors: Joaquín
authors: J
authors: Del Río
authors: Diana
authors: D
authors: Frechilla
mesh_terms: D051339:Actin Depolymerizing Factors / Q000378:metabolism; D000544:Alzheimer Disease / Q000235:genetics / Q000378:metabolism* / Q000503:physiopathology; D016564:Amyloid beta-Protein Precursor / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D015153:Blotting, Western; D002478:Cells, Cultured; D003071:Cognition; D004195:Disease Models, Animal; D005786:Gene Expression Regulation; D006624:Hippocampus / Q000378:metabolism*; D006801:Humans; D008568:Memory; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009483:Neuropsychological Tests; D011180:Postmortem Changes; D036122:Receptor, EphA4 / Q000378:metabolism*; D036183:Receptor, EphB2 / Q000378:metabolism*; D018091:Receptors, AMPA / Q000378:metabolism; D016194:Receptors, N-Methyl-D-Aspartate / Q000378:metabolism; D021641:Recognition, Psychology; D013028:Space Perception; D013997:Time Factors
chemical_list: D051339:Actin Depolymerizing Factors; D016564:Amyloid beta-Protein Precursor; D018091:Receptors, AMPA; D016194:Receptors, N-Methyl-D-Aspartate; D036122:Receptor, EphA4; D036183:Receptor, EphB2