title: Cognitive deficits and disruption of neurogenesis in a mouse model of apolipoprotein E4 domain interaction.
abstract: Apolipoprotein E4 (apoE4) allele is the major genetic risk factor for sporadic Alzheimer disease (AD) due to the higher prevalence and earlier onset of AD in apoE4 carriers. Accumulating data suggest that the interaction between the N- and the C-terminal domains in the protein may be the main pathologic feature of apoE4. To test this hypothesis, we used Arg-61 mice, a model of apoE4 domain interaction, by introducing the domain interaction feature of human apoE4 into native mouse apoE. We carried out hippocampus-dependent learning and memory tests and related cellular and molecular assays on 12- and 3-month-old Arg-61 and age-matched background C57BL/6J mice. Learning and memory task performance were impaired in Arg-61 mice at both old and young ages compared with C57BL/6J mice. Surprisingly, young Arg-61 mice had more mitotic doublecortin-positive cells in the subgranular zone; mRNA levels of brain-derived neurotrophic factor (BDNF) and TrkB were also higher in 3-month-old Arg-61 hippocampus compared with C57BL/6J mice. These early-age neurotrophic and neurogenic (proliferative) effects in the Arg-61 mouse may be an inadequate compensatory but eventually detrimental attempt by the system to "repair" itself. This is supported by the higher cleaved caspase-3 levels in the young animals that not only persisted, but increased in old age, and the lower levels of doublecortin at old age in the hippocampus of Arg-61 mice. These results are consistent with human apoE4-dependent cognitive and neuro-pathologic changes, supporting the principal role of domain interaction in the pathologic effect of apoE4. Domain interaction is, therefore, a viable therapeutic/prophylactic target for cognitive impairment and AD in apoE4 subjects.
authors: From the Department of Pathology.
authors: Samuel O
authors: SO
authors: Adeosun
authors: Xu
authors: X
authors: Hou
authors: Baoying
authors: B
authors: Zheng
authors: Craig
authors: C
authors: Stockmeier
authors: Xiaoming
authors: X
authors: Ou
authors: Ian
authors: I
authors: Paul
authors: Thomas
authors: T
authors: Mosley
authors: Karl
authors: K
authors: Weisgraber
authors: Jun Ming
authors: JM
authors: Wang
mesh_terms: D000375:Aging / Q000473:pathology*; D000544:Alzheimer Disease / Q000473:pathology*; D000818:Animals; D053327:Apolipoprotein E4 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D019208:Brain-Derived Neurotrophic Factor / Q000378:metabolism; D053148:Caspase 3 / Q000378:metabolism; D003072:Cognition Disorders / Q000473:pathology*; D004195:Disease Models, Animal; D000089622:Doublecortin Domain Proteins; D006801:Humans; D018782:Maze Learning; D008569:Memory Disorders / Q000473:pathology*; D051379:Mice; D008810:Mice, Inbred C57BL; D008869:Microtubule-Associated Proteins / Q000235:genetics / Q000378:metabolism; D055495:Neurogenesis / Q000502:physiology*; D009479:Neuropeptides / Q000235:genetics / Q000378:metabolism; D017434:Protein Structure, Tertiary; D020813:Receptor, trkB / Q000378:metabolism
chemical_list: D053327:Apolipoprotein E4; D019208:Brain-Derived Neurotrophic Factor; D000089622:Doublecortin Domain Proteins; D008869:Microtubule-Associated Proteins; D009479:Neuropeptides; D020813:Receptor, trkB; C505409:Casp3 protein, mouse; D053148:Caspase 3
keywords: Alzheimer Disease; Antagonistic Pleiotropy; ApoE; Apoptosis; BDNF; Doublecortin; Learning and Memory; Neurogenesis; Protein Domains