Middle-aged human apoE4 targeted-replacement mice show retention deficits on a wide range of spatial memory tasks.
Apolipoprotein (apo) E4, one of three human apoE (h-apoE) isoforms, has been identified as a major genetic risk factor for Alzheimer's disease and for cognitive deficits associated with aging. However, the biological mechanisms involving apoE in learning and memory processes are unclear. A potential isoform-dependent role of apoE in cognitive processes was studied in human apoE targeted-replacement (TR) mice. These mice express either the human apoE3 or apoE4 gene under the control of endogenous murine apoE regulatory sequences, resulting in physiological expression of h-apoE in both a temporal and spatial pattern similar to humans. Male and female apoE3-TR, apoE4-TR, apoE-knockout and C57BL/6J mice (15-18 months) were tested with spatial memory and avoidance conditioning tasks. Compared to apoE3-TR mice, spatial memory in female apoE4-TR mice was impaired based on their poor performances in; (i) the probe test of the water-maze reference memory task, (ii) the water-maze working memory task and (iii) an active avoidance Y-maze task. Retention performance on a passive avoidance task was also impaired in apoE4-TR mice, but not in other genotypes. These deficits in both spatial and avoidance memory tasks may be related to the anatomical and functional abnormalities previously reported in the hippocampus and the amygdala of apoE4-TR mice. We conclude that the apoE4-TR mice provide an excellent model for understanding the mechanisms underlying apoE4-dependent susceptibility to cognitive decline.
Laboratoire de Neurosciences Comportementales et Cognitives, Université Louis Pasteur, CNRS-UMR 7191, IFR 37, GDR CNRS 2905, 12 rue Goethe, 67000 Strasbourg, France.
Alexandra
A
Bour
Jeannette
J
Grootendorst
Elise
E
Vogel
Christian
C
Kelche
Jean-Cosme
JC
Dodart
Kelly
K
Bales
Pierre-Henri
PH
Moreau
Patrick M
PM
Sullivan
Chantal
C
Mathis
D000818:Animals; D053318:Apolipoprotein E3 / Q000235:genetics / Q000502:physiology; D053327:Apolipoprotein E4 / Q000235:genetics / Q000502:physiology*; D001057:Apolipoproteins E / Q000235:genetics / Q000502:physiology; D001362:Avoidance Learning / Q000502:physiology; D001522:Behavior, Animal / Q000502:physiology; D003071:Cognition / Q000502:physiology; D005106:Exploratory Behavior / Q000502:physiology; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D018782:Maze Learning / Q000502:physiology; D008568:Memory / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008822:Mice, Transgenic; D008875:Middle Aged; D012153:Retention, Psychology / Q000502:physiology*; D013037:Spatial Behavior / Q000502:physiology*
D053318:Apolipoprotein E3; D053327:Apolipoprotein E4; D001057:Apolipoproteins E