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Buchanan H, Hull C, Cacho Barraza M, Delibegovic M, Platt B. Apolipoprotein E loss of function: Influence on murine brain markers of physiology and pathology. AGING BRAIN 2022; 2:100055. [PMID: 36908879 PMCID: PMC9997145 DOI: 10.1016/j.nbas.2022.100055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 10/11/2022] [Accepted: 10/13/2022] [Indexed: 12/15/2022] Open
Abstract
The canonical role of Apolipoprotein E (ApoE) is related to lipid and cholesterol metabolism, however, additional functions of this protein have not been fully described. Given the association of ApoE with diseases such as Alzheimer's Disease (AD), it is clear that further characterisation of its roles, especially within the brain, is needed. Therefore, using protein and gene expression analyses of neonatal and 6-month old brain tissues from an ApoE knockout mouse model, we examined ApoE's contribution to several CNS pathways, with an emphasis on those linked to AD. Early neonatal changes associated with ApoE-/- were observed, with decreased soluble phosphorylated tau (p-tau, -40 %), increased synaptophysin (+36 %) and microglial Iba1 protein levels (+25 %) vs controls. Progression of the phenotype was evident upon analysis of 6-month-old tissue, where decreased p-tau was also confirmed in the insoluble fraction, alongside reduced synaptic and increased amyloid precursor protein (APP) protein levels. An age comparison further underlined deviations from WT animals and thus the impact of ApoE loss on neuronal maturation. Taken together, our data implicate ApoE modulation of multiple CNS roles. Loss of function is associated with alterations from birth, and include synaptic deficits, neuroinflammation, and changes to key AD pathologies, amyloid-β and tau.
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Affiliation(s)
| | | | | | | | - Bettina Platt
- Corresponding author at: Chair in Translational Neuroscience, School of Medicine, Medical Sciences & Nutrition, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, Scotland, UK.
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He Q, Yu F, Cong M, Ji Y, Zhang Q, Ding F. Comparative Proteomic Analysis of Differentially Expressed Proteins between Injured Sensory and Motor Nerves after Peripheral Nerve Transection. J Proteome Res 2020; 20:1488-1508. [PMID: 33284006 DOI: 10.1021/acs.jproteome.0c00639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Peripheral nerve repair and functional recovery depend on the rate of nerve regeneration and the quality of target reinnervation. It is important to fully understand the cellular and molecular basis underlying the specificity of peripheral nerve regeneration, which means achieving corresponding correct pathfinding and accurate target reinnervation for regrowing motor and sensory axons. In this study, a quantitative proteomic technique, based on isobaric tags for relative and absolute quantitation (iTRAQ), was used to profile the protein expression pattern between single motor and sensory nerves at 14 days after peripheral nerve transection. Among a total of 1259 proteins identified, 176 proteins showed the differential expressions between injured motor and sensory nerves. Quantitative RT-PCR and western blot analysis were applied to validate the proteomic data on representative differentially expressed proteins. Functional categorization indicated that differentially expressed proteins were linked to a diverse array of molecular functions, including axonogenesis, response to axon injury, tissue remodeling, axon ensheathment, cell proliferation and adhesion, vesicle-mediated transport, response to oxidative stress, internal signal cascade, and macromolecular complex assembly, which might play an essential role in peripheral motor and sensory nerve regeneration. Overall, we hope that the proteomic database obtained in this study could serve as a solid foundation for the comprehensive investigation of differentially expressed proteins between injured motor and sensory nerves and for the mechanism elucidation of the specificity of peripheral nerve regeneration. Data are available via ProteomeXchange with identifier PXD022097.
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Affiliation(s)
- Qianru He
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-Innovation Center of Neuroregeneration, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Nantong University, Nantong, JS 226001, PR China
| | - Fanhui Yu
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-Innovation Center of Neuroregeneration, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Nantong University, Nantong, JS 226001, PR China
| | - Meng Cong
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-Innovation Center of Neuroregeneration, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Nantong University, Nantong, JS 226001, PR China
| | - Yuhua Ji
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-Innovation Center of Neuroregeneration, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Nantong University, Nantong, JS 226001, PR China
| | - Qi Zhang
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-Innovation Center of Neuroregeneration, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Nantong University, Nantong, JS 226001, PR China
| | - Fei Ding
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-Innovation Center of Neuroregeneration, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Nantong University, Nantong, JS 226001, PR China
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Tan Y, Nie S, Zhu W, Liu F, Guo H, Chu J, Cao XB, Jiang X, Zhang Y, Li Y. 7,8-Dihydroxyflavone Ameliorates Cognitive Impairment by Inhibiting Expression of Tau Pathology in ApoE-Knockout Mice. Front Aging Neurosci 2016; 8:287. [PMID: 27965573 PMCID: PMC5126466 DOI: 10.3389/fnagi.2016.00287] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2016] [Accepted: 11/14/2016] [Indexed: 11/13/2022] Open
Abstract
7,8-Dihydroxyflavone (7,8-DHF), a tyrosine kinase B agonist that mimics the neuroprotective properties of brain-derived neurotrophic factor, which can not efficiently deliver into the brain, has been reported to be useful in ameliorating cognitive impairment in many diseases. Researches have indicated that apolipoprotein E-knockout (ApoE-KO) mouse was associated with cognitive alteration via various mechanisms. Our present study investigated the possible mechanisms of cognitive impairment of ApoE-KO mouse fed with western type diet and the protective effects of 7,8-DHF in improving spatial learning and memory in ApoE-KO mouse. Five-weeks-old ApoE-KO mice and C57BL/6 mice were chronically treated with 7,8-DHF (with a dosage of 5 mg/kg) or vehicles orally for 25 weeks, and then subjected to Morris water maze at the age of 30 weeks to evaluate the cognitive performances. Afterward, histology analysis and western blotting were performed. Spatial learning and memory deficits were observed in ApoE-KO mice, which were consistent with higher expression of active-asparaginyl endopeptidase (active-AEP) as well as AEP-derived truncated tau N368 compared with normal group. In addition to that, long-term treatment of 7,8-DHF dramatically ameliorated cognitive decline in ApoE-KO mice, accompanied by the activation in phosphorylated protein kinase B (Akt)/glycogen synthase kinase-3β (GSK-3β) pathway and down-regulated expression of tau S396 and PHF-tau (phosphorylated tau at ser396 and ser404 epitope). These findings suggested that cognitive impairment of ApoE-KO mouse might associate with tau pathology and 7,8-DHF could activate AKT and then phosphorylate its downstream molecule to inhibit expression of abnormal tau, meanwhile, 7,8-DHF could reduce the expression of active-AEP and then inhibit production of truncated tau N368.
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Affiliation(s)
- Yang Tan
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology Wuhan, China
| | - Shuke Nie
- Department of Neurology, Renmin Hospital of Wuhan University Wuhan, China
| | - Wende Zhu
- Department of Neurosurgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology Wuhan, China
| | - Fang Liu
- Department of Medicine, LuoHu Chronic Disease Control and Cure Hospital Shenzhen, China
| | - Hailong Guo
- Department of Pharmacy, The Eighth Affiliated Hospital of Sun Yat-sen University Shenzhen, China
| | - Jiewen Chu
- Department of Pharmacy, The Eighth Affiliated Hospital of Sun Yat-sen University Shenzhen, China
| | - Xue B Cao
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology Wuhan, China
| | - Xingjun Jiang
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology Wuhan, China
| | - Yunjian Zhang
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology Wuhan, China
| | - Yuzhen Li
- Department of Pharmacy, The Eighth Affiliated Hospital of Sun Yat-sen University Shenzhen, China
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Protective Effect of Genistein against Neuronal Degeneration in ApoE -/- Mice Fed a High-Fat Diet. Nutrients 2016; 8:nu8110692. [PMID: 27809235 PMCID: PMC5133079 DOI: 10.3390/nu8110692] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Revised: 10/26/2016] [Accepted: 10/27/2016] [Indexed: 01/08/2023] Open
Abstract
Altered cholesterol metabolism is believed to play a causal role in major pathophysiological changes in neurodegeneration. Several studies have demonstrated that the absence of apolipoprotein E (ApoE), a predominant apolipoprotein in the brain, leads to an increased susceptibility to neurodegeneration. Previously, we observed that genistein, a soy isoflavone, significantly alleviated apoptosis and tau hyperphosphorylation in SH-SY5Y cells. Therefore, we investigated the neuroprotective effects of dietary genistein supplementation (0.5 g/kg diet) in the cortex and hippocampus of wild-type C57BL/6 (WT) and ApoE knockout (ApoE−/−) mice fed a high-fat diet (HFD) for 24 weeks. Genistein supplementation alleviated neuroinflammation and peripheral and brain insulin resistance. Reductions in oxidative and endoplasmic reticulum stress were also observed in ApoE−/− mice fed a genistein-supplemented diet. Beta-secretase 1 and presenilin 1 mRNA levels and beta-amyloid peptide (Aβ) protein levels were reduced in response to genistein supplementation in ApoE−/− mice but not in WT mice. Although the absence of ApoE did not increase tau hyperphosphorylation, genistein supplementation reduced tau hyperphosphorylation in both WT and ApoE−/− mice. Consistent with this result, we also observed that genistein alleviated activity of c-Jun N-terminal kinase and glycogen synthase kinase 3β, which are involved in tau hyperphosphorylation. Taken together, these results demonstrate that genistein alleviated neuroinflammation, Aβ deposition, and hyperphosphorylation in ApoE−/− mice fed an HFD.
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Lawrence DW, Comper P, Hutchison MG, Sharma B. The role of apolipoprotein E episilon (ɛ)-4 allele on outcome following traumatic brain injury: A systematic review. Brain Inj 2015; 29:1018-31. [DOI: 10.3109/02699052.2015.1005131] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Effects of shenque moxibustion on behavioral changes and brain oxidative state in apolipoprotein e-deficient mice. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2015; 2015:804804. [PMID: 25793004 PMCID: PMC4352425 DOI: 10.1155/2015/804804] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Accepted: 02/02/2015] [Indexed: 01/06/2023]
Abstract
Purpose. To determine whether moxibustion influences the learning and memory behavior of ApoE−/− male mice, and investigate the mechanism of moxibustion on the alteration of oxidized proteins (glial fibrillary acidic protein, β-amyloid) in hippocampus. Methods. Thirty-three ApoE−/− mice were randomly divided into 3 groups (n = 11/group): moxibustion, sham moxibustion, and no treatment control. Wild-type C57BL/6 mice (n = 13) were used for normal control. Moxibustion was performed with Shenque (RN8) moxibustion for 20 minutes per day, 6 days/week for 12 weeks. In sham control, the procedure was similar except burning of the moxa stick. Behavioral tests (step-down test and Morris water maze task) were conducted in the 13th week. The mice were then sacrificed and the tissues were harvested for immune-histochemical staining. Results. In the step-down test, the moxibustion group had shorter reaction time in training record and committed less mistakes compared to sham control. In immune-histochemical study, the moxibustion group expressed lower level of GFAP and less aggregation of β-amyloid in the hippocampus than the sham control. Conclusion. Our findings suggest that moxibustion may enhance learning capability of ApoE−/− mice. The mechanism may be via inhibiting oxidized proteins (GFAP and β-amyloid) in astrocytes.
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Jasmin SB, Pearson V, Lalonde D, Domenger D, Théroux L, Poirier J. Differential regulation of ABCA1 and ABCG1 gene expressions in the remodeling mouse hippocampus after entorhinal cortex lesion and liver-X receptor agonist treatment. Brain Res 2014; 1562:39-51. [PMID: 24661912 DOI: 10.1016/j.brainres.2014.03.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2014] [Revised: 03/14/2014] [Accepted: 03/15/2014] [Indexed: 12/30/2022]
Abstract
Entorhinal cortex lesioning (ECL) causes an extensive deafferentation of the hippocampus that is classically followed by a compensatory reinnervation, where apolipoprotein E, the main extracellular lipid-carrier in the CNS, has been shown to play a crucial role by shuttling cholesterol to reconstructing neurons terminals. Hence, we investigated whether the ATP-binding cassette (ABC) transporters -A1 and -G1, known to regulate cellular cholesterol efflux and lipidation of the apolipoprotein E-containing lipoprotein complex are actively involved in this context of brain׳s plastic response to neurodegeneration and deafferentation. We assessed ABCA1 and ABCG1 mRNA and protein levels throughout the degenerative phase and the reinnervation process and evaluated the associated cholinergic sprouting following ECL in the adult mouse brain. We subsequently tested the effect of the pharmacological activation of the nuclear receptor LXR, prior to versus after ECL, on hippocampal ABCA1 and G1 expression and on reinnervation. ECL induced a time-dependent up-regulation of ABCA1, but not G1, that coincided with a significant increase in acetylcholine esterase (AChE) activity in the ipsilateral hippocampus. Pre-ECL, but not post-ECL i.p. treatment with the LXR agonist TO901317 also led to a significant increase solely in hippocampal ABCA1 expression, paralleled by increases in both AchE and synaptophysin protein levels in the deafferented hippocampus. Thus, ABCA1 and -G1 are differentially regulated in the lesioned brain and upon treatment with an LXR agonist. Further, TO901317-induced up-regulation of ABCA1 appears to be more beneficial in a prevention (pre-lesion) than rescue (post-lesion) treatment; both findings support a central role for ABC transporters in brain plasticity.
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Affiliation(s)
- Stéphanie Bélanger Jasmin
- Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada H4A 2B4; Douglas Mental Health University Institute, 6875 LaSalle Blvd, Verdun, Quebec, Canada H4H 1R3
| | - Vanessa Pearson
- Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada H4A 2B4; Douglas Mental Health University Institute, 6875 LaSalle Blvd, Verdun, Quebec, Canada H4H 1R3
| | - Daphnée Lalonde
- Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada H4A 2B4; Douglas Mental Health University Institute, 6875 LaSalle Blvd, Verdun, Quebec, Canada H4H 1R3
| | - Dorothée Domenger
- Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada H4A 2B4; Douglas Mental Health University Institute, 6875 LaSalle Blvd, Verdun, Quebec, Canada H4H 1R3
| | - Louise Théroux
- Douglas Mental Health University Institute, 6875 LaSalle Blvd, Verdun, Quebec, Canada H4H 1R3
| | - Judes Poirier
- Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada H4A 2B4; Douglas Mental Health University Institute, 6875 LaSalle Blvd, Verdun, Quebec, Canada H4H 1R3.
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8
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Bink DI, Ritz K, Aronica E, van der Weerd L, Daemen MJAP. Mouse models to study the effect of cardiovascular risk factors on brain structure and cognition. J Cereb Blood Flow Metab 2013; 33:1666-84. [PMID: 23963364 PMCID: PMC3824184 DOI: 10.1038/jcbfm.2013.140] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2013] [Revised: 06/24/2013] [Accepted: 07/16/2013] [Indexed: 12/13/2022]
Abstract
Recent clinical data indicates that hemodynamic changes caused by cardiovascular diseases such as atherosclerosis, heart failure, and hypertension affect cognition. Yet, the underlying mechanisms of the resulting vascular cognitive impairment (VCI) are poorly understood. One reason for the lack of mechanistic insights in VCI is that research in dementia primarily focused on Alzheimer's disease models. To fill in this gap, we critically reviewed the published data and various models of VCI. Typical findings in VCI include reduced cerebral perfusion, blood-brain barrier alterations, white matter lesions, and cognitive deficits, which have also been reported in different cardiovascular mouse models. However, the tests performed are incomplete and differ between models, hampering a direct comparison between models and studies. Nevertheless, from the currently available data we conclude that a few existing surgical animal models show the key features of vascular cognitive decline, with the bilateral common carotid artery stenosis hypoperfusion mouse model as the most promising model. The transverse aortic constriction and myocardial infarction models may be good alternatives, but these models are as yet less characterized regarding the possible cerebral changes. Mixed models could be used to study the combined effects of different cardiovascular diseases on the deterioration of cognition during aging.
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Affiliation(s)
- Diewertje I Bink
- Department of Pathology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
- Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Katja Ritz
- Department of Pathology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Eleonora Aronica
- Department of Pathology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
- SEIN—Stichting Epilepsie Instellingen Nederland, Heemstede, The Netherlands
- Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam, Amsterdam, The Netherlands
| | - Louise van der Weerd
- Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Mat JAP Daemen
- Department of Pathology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
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Fernandez-Vizarra P, Lopez-Franco O, Mallavia B, Higuera-Matas A, Lopez-Parra V, Ortiz-Muñoz G, Ambrosio E, Egido J, Almeida OFX, Gomez-Guerrero C. Immunoglobulin G Fc receptor deficiency prevents Alzheimer-like pathology and cognitive impairment in mice. Brain 2012; 135:2826-37. [PMID: 22961553 DOI: 10.1093/brain/aws195] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Alzheimer's disease is a severely debilitating disease of high and growing proportions. Hypercholesterolaemia is a key risk factor in sporadic Alzheimer's disease that links metabolic disorders (diabetes, obesity and atherosclerosis) with this pathology. Hypercholesterolaemia is associated with increased levels of immunoglobulin G against oxidized lipoproteins. Patients with Alzheimer's disease produce autoantibodies against non-brain antigens and specific receptors for the constant Fc region of immunoglobulin G have been found in vulnerable neuronal subpopulations. Here, we focused on the potential role of Fc receptors as pathological players driving hypercholesterolaemia to Alzheimer's disease. In a well-established model of hypercholesterolaemia, the apolipoprotein E knockout mouse, we report increased brain levels of immunoglobulin G and upregulation of activating Fc receptors, predominantly of type IV, in neurons susceptible to amyloid β accumulation. In these mice, gene deletion of γ-chain, the common subunit of activating Fc receptors, prevents learning and memory impairments without influencing cholesterolaemia and brain and serum immunoglobulin G levels. These cognition-protective effects were associated with a reduction in synapse loss, tau hyperphosphorylation and intracellular amyloid β accumulation both in cortical and hippocampal pyramidal neurons. In vitro, activating Fc receptor engagement caused synapse loss, tau hyperphosphorylation and amyloid β deposition in primary neurons by a mechanism involving mitogen-activated protein kinases and β-site amyloid precursor protein cleaving enzyme 1. Our results represent the first demonstration that immunoglobulin G Fc receptors contribute to the development of hypercholesterolaemia-associated features of Alzheimer's disease and suggest a new potential target for slowing or preventing Alzheimer's disease in hypercholesterolaemic patients.
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Affiliation(s)
- Paula Fernandez-Vizarra
- Renal and Vascular Inflammation, Nephrology Department, IIS-Fundacion Jimenez Diaz, Autonoma University, Avda. Reyes Catolicos 2, 28040 Madrid, Spain
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Tai LM, Youmans KL, Jungbauer L, Yu C, Ladu MJ. Introducing Human APOE into Aβ Transgenic Mouse Models. Int J Alzheimers Dis 2011; 2011:810981. [PMID: 22028984 PMCID: PMC3199079 DOI: 10.4061/2011/810981] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2011] [Accepted: 08/15/2011] [Indexed: 12/29/2022] Open
Abstract
Apolipoprotein E (apoE) and apoE/amyloid-β (Aβ) transgenic (Tg) mouse models are critical to understanding apoE-isoform effects on Alzheimer's disease risk. Compared to wild type, apoE−/− mice exhibit neuronal deficits, similar to apoE4-Tg compared to apoE3-Tg mice, providing a model for Aβ-independent apoE effects on neurodegeneration. To determine the effects of apoE on Aβ-induced neuropathology, apoE−/− mice were crossed with Aβ-Tg mice, resulting in a significant delay in plaque deposition. Surprisingly, crossing human-apoE-Tg mice with apoE−/−/Aβ-Tg mice further delayed plaque deposition, which eventually developed in apoE4/Aβ-Tg mice prior to apoE3/Aβ-Tg. One approach to address hAPOE-induced temporal delay in Aβ pathology is an additional insult, like head injury. Another is crossing human-apoE-Tg mice with Aβ-Tg mice that have rapid-onset Aβ pathology. For example, because 5xFAD mice develop plaques by 2 months, the prediction is that human-apoE/5xFAD-Tg mice develop plaques around 6 months and 12 months before other human-apoE/Aβ-Tg mice. Thus, tractable models for human-apoE/Aβ-Tg mice continue to evolve.
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Affiliation(s)
- Leon M Tai
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL 60612, USA
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Klein RC, Mace BE, Moore SD, Sullivan PM. Progressive loss of synaptic integrity in human apolipoprotein E4 targeted replacement mice and attenuation by apolipoprotein E2. Neuroscience 2010; 171:1265-72. [PMID: 20951774 DOI: 10.1016/j.neuroscience.2010.10.027] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2010] [Revised: 09/22/2010] [Accepted: 10/12/2010] [Indexed: 01/30/2023]
Abstract
Inheritance of the APOE4 allele is a well established genetic risk factor linked to the development of late onset Alzheimer's disease. As the major lipid transport protein in the central nervous system, apolipoprotein (apo) E plays an important role in the assembly and maintenance of synaptic connections. Our previous work showed that 7 month old human apoE4 targeted replacement (TR) mice displayed significant synaptic deficits in the principal neurons of the lateral amygdala, a region that is critical for memory formation and also one of the primary regions affected in Alzheimer's disease, compared to apoE3 TR mice. In the current study, we determined how age and varying APOE genotype affect synaptic integrity of amygdala neurons by comparing electrophysiological and morphometric properties in C57BL6, apoE knockout, and human apoE3, E4 and E2/4 TR mice at 1 month and 7 months. The apoE4 TR mice exhibited the lowest level of excitatory synaptic activity and dendritic arbor compared to other cohorts at both ages, and became progressively worse by 7 months. In contrast, the apoE3 TR mice exhibited the highest synaptic activity and dendritic arbor of all cohorts at both ages. C57BL6 mice displayed virtually identical synaptic activity to apoE3 TR mice at 1 month; however this activity decreased by 7 months. ApoE knockout mice exhibited a similar synaptic activity profile with apoE4 TR mice at 7 months. Consistent with previous reports that APOE2 confers protection, the apoE4-dependent deficits in excitatory activity were significantly attenuated in apoE2/4 TR mice at both ages. These findings demonstrate that expression of human apoE4 contributes to functional deficits in the amygdala very early in development and may be responsible for altering neuronal circuitry that eventually leads to cognitive and affective disorders later in life.
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Affiliation(s)
- R C Klein
- Department of Psychiatry, Duke University Medical Center, Durham, NC 27710, USA
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Kosacka J, Gericke M, Nowicki M, Kacza J, Borlak J, Spanel-Borowski K. Apolipoproteins D and E3 exert neurotrophic and synaptogenic effects in dorsal root ganglion cell cultures. Neuroscience 2009; 162:282-91. [PMID: 19414061 DOI: 10.1016/j.neuroscience.2009.04.073] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2009] [Revised: 04/27/2009] [Accepted: 04/29/2009] [Indexed: 11/17/2022]
Abstract
Co-cultures of 3T3-L1 adipocytes with neurons from the rat dorsal root ganglia (DRG) showed enhanced neuritogenesis and synaptogenesis. Microarray analysis for upregulated genes in adipocyte/DRG co-cultures currently points to apolipoproteins D and E (ApoD, ApoE) as influential proteins. We therefore tested adipocyte-secreted cholesterol and the carrier proteins ApoD and ApoE3. Cholesterol, ApoD, and ApoE3 each increased neurite outgrowth and upregulated the expression of presynaptic synaptophysin and synaptotagmin, as well as the postsynaptic density protein 95. The neurotrophic effects of ApoD and ApoE3 were associated with an increased expression of the low-density lipoprotein receptor and apolipoprotein E receptor 2. Simultaneous treatment with receptor-associated protein, an apolipoprotein receptor antagonist, inhibited the neurotrophic function of both apolipoproteins. The application of ApoD, ApoE3, and cholesterol to DRG cell cultures corresponded with increased expression of the chemokine stromal cell-derived factor 1 and its receptor CXC chemokine receptor 4 (CXCR4). Surprisingly, the inhibition of CXCR4 by the antagonistic drug AMD3100 decreased the apolipoprotein/cholesterol dependent neurotrophic effects. We thus assume that apolipoprotein-induced neuritogenesis in DRG cells interferes with CXCR4 signaling, and that adipocyte-derived apolipoproteins might be helpful in nerve repair.
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Affiliation(s)
- J Kosacka
- Institute of Anatomy, University of Leipzig, Liebigstrabetae 13, D-04103 Leipzig, Germany.
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Poirier J. Apolipoprotein E represents a potent gene-based therapeutic target for the treatment of sporadic Alzheimer's disease. Alzheimers Dement 2008; 4:S91-7. [PMID: 18632009 DOI: 10.1016/j.jalz.2007.11.012] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- Judes Poirier
- McGill Centre for Studies in Aging and Douglas Mental Health University Institute, Montreal, Quebec, Canada.
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Pardon MC. Stress and ageing interactions: A paradox in the context of shared etiological and physiopathological processes. ACTA ACUST UNITED AC 2007; 54:251-73. [PMID: 17408561 DOI: 10.1016/j.brainresrev.2007.02.007] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2007] [Revised: 02/15/2007] [Accepted: 02/22/2007] [Indexed: 12/18/2022]
Abstract
Gerontology has made considerable progress in the understanding of the mechanisms underlying the ageing process and age-related neurodegenerative disorders. However, ways to improve quality of life in the elderly remain to be elucidated. It is now clear that stress and the ageing process share a number of underlying mechanisms bound in a very close, if not indissociable, relationship. The ageing process is regulated by the factors underlying the ability to adjust to stress, whilst stress has an influence on the life span and the quality of ageing. In addition, the ability to cope with stress in adulthood predicts life expectancy and quality of life at senescence. The ageing process and stress also share several common mechanisms, particularly in relation to the energy factor. Stress consumes energy and ageing may be considered as a cost of the energy expended to deal with the stressors to which the body is exposed throughout its lifetime. This suggests that the ageing process is associated with and/or a consequence of a long-lasting activation of the major stress responsive systems. However, despite common features, the interaction between stress and the ageing process gives rise to some paradoxes. Stress can either diminish or exacerbate the ageing process just as the ageing process can worsen or counter the effects of stress. There has been little attempt to understand how ageing and stress might interact to promote "successful" or pathological ageing. A key factor in this respect is the individual's ability to adapt to stress. Viewed from this angle, the quality of life of aged subjects may be improved through therapy designed to improve the tolerance to stress.
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Affiliation(s)
- Marie-Christine Pardon
- Institute of Neuroscience, School of Biomedical Sciences, University of Nottingham Medical School, Queen's Medical Centre, Nottingham, NG7 2UH, UK.
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15
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Chen GH, Wang YJ, Qin S, Yang QG, Zhou JN, Liu RY. Age-related spatial cognitive impairment is correlated with increase of synaptotagmin 1 in dorsal hippocampus in SAMP8 mice. Neurobiol Aging 2007; 28:611-8. [PMID: 16677738 DOI: 10.1016/j.neurobiolaging.2006.03.001] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2005] [Revised: 02/28/2006] [Accepted: 03/03/2006] [Indexed: 11/29/2022]
Abstract
The age-related decline of learning and memory is a common phenomenon in humans and animals, even though the underlying mechanism is not yet known. In the present study, we propose that synaptotagmin 1 (Syt 1) might be a synaptic protein involved in the loss of learning and memory with aging. To test this hypothesis, the age-related spatial cognitive ability of 36 P8 mice (15 mice aged 4 months, 11 mice aged 8 months and 10 mice aged 13 months) was measured in a Morris water maze. After the behavioral test, both the protein and mRNA levels of Syt 1 were determined in the dorsal hippocampus by means of immunocytochemistry and reverse transcriptase polymerase chain reaction (RT-PCR), respectively. In the Morris water maze, the latency of the 4-month mice to find the submerged platform was significantly shorter than that of the older mice, while there were no significant differences between the 8- and 13-month-old mice in this respect. Compared to the 4-month-old mice, the Syt 1 protein in the 13-month-old mice was significantly increased in almost all layers of each subfield of the hippocampus. The average level of Syt 1 mRNA in the dorsal hippocampus of the P8 mice had not changed with aging. The latency of the 13-month-old P8 mice tested in the Morris water maze was positively correlated with the Syt 1 immunoreactivity in four circuit-specific regions in the dorsal hippocampus. Interestingly, the latency in the Morris water maze was also positively correlated with the level of Syt 1 mRNA in the dorsal hippocampus in individual aged P8 mouse. These results suggest that increased Syt 1 in the dorsal hippocampus in aged mice might be responsible for the age-related impairment of learning and memory.
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Affiliation(s)
- Gui-Hai Chen
- Department of Neurology, Anhui Geriatric Institute, The First Affiliated Hospital of Anhui Medical University, Hefei 230022, PR China
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16
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Wang C, Wilson WA, Moore SD, Mace BE, Maeda N, Schmechel DE, Sullivan PM. Human apoE4-targeted replacement mice display synaptic deficits in the absence of neuropathology. Neurobiol Dis 2005; 18:390-8. [PMID: 15686968 DOI: 10.1016/j.nbd.2004.10.013] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2004] [Revised: 09/29/2004] [Accepted: 10/21/2004] [Indexed: 10/25/2022] Open
Abstract
The human APOE*4 allele is associated with an early age of onset and increased risk of Alzheimer's disease (AD). Long before the onset of AD, cognitive deficits can be identified in APOE*4 carriers. We examined neurons in the lateral amygdala of young apolipoprotein (apo) E3 and apoE4 targeted replacement (TR) mice for changes in synaptic integrity. ApoE4 mice displayed significantly reduced excitatory synaptic transmission and dendritic arborization. Despite these changes there were no signs of gliosis, amyloid deposition or neurofibrillary tangles in these mice. To our knowledge, this is the first study to suggest that cognitive deficits in APOE*4 carriers are due to inherent defects in synaptic function that appear prior to any age-dependent markers of neuropathology.
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Affiliation(s)
- Chunsheng Wang
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA
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17
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Everett AW, Ernst EJ. Increased quantal size in transmission at slow but not fast neuromuscular synapses of apolipoprotein E deficient mice. Exp Neurol 2004; 185:290-6. [PMID: 14736510 DOI: 10.1016/j.expneurol.2003.10.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Uncertainties from the literature concerning the role of apolipoprotein E (apoE) in central cholinergic function prompted us to investigate what effect apoE may have on transmission at the neuromuscular junction. Both spontaneous and evoked release were measured in isolated extensor digitorum longus (edl) and soleus muscles from both wild-type and apoE-deficient mice. Miniature endplate and nerve-evoked endplate potentials (MEPPs and EPPs, respectively) were indistinguishable in edl muscles in both groups of mice; however, MEPP amplitudes in soleus muscles were significantly larger (by an average of 23%) in apoE-deficient mice compared with 5- to 7-week-old age-matched wild-type mice. The EPP amplitudes were also larger in soleus muscles in the mutant mice, but this was a reflection of the larger quantal size in this muscle because quantal content, determined from the ratio of the average EPP amplitude to average MEPP amplitude, was unchanged from normal in the mutant mice. The MEPP frequency and the percent of nerve stimulations failing to produce an EPP were unchanged from normal in both muscle types in the mutant mice. The difference in quantal size in soleus muscle transmission between mutant and wild-type mice was abolished in the presence of neostigmine, an acetylcholinesterase inhibitor. The results suggest that apoE normally associates with acetylcholinesterase in the synaptic cleft of slow muscles, modulating the activity of the enzyme and therefore quantal size.
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Affiliation(s)
- A W Everett
- Physiology, M311, School of Biomedical and Chemical Sciences, The University of Western Australia, Crawley 6009, Australia.
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18
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Lee Y, Aono M, Laskowitz D, Warner DS, Pearlstein RD. Apolipoprotein E protects against oxidative stress in mixed neuronal-glial cell cultures by reducing glutamate toxicity. Neurochem Int 2004; 44:107-18. [PMID: 12971913 DOI: 10.1016/s0197-0186(03)00112-8] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Apolipoprotein E (ApoE) deficiency has been shown to adversely affect outcome after transient cerebral ischemia and head trauma. Since oxidative stress contributes to these injuries, the ability of ApoE to reduce irreversible oxidative damage was studied in primary mixed neuronal-glial cell cultures. Cells (13-16 days in vitro) were exposed to 50 microM hydrogen peroxide (H2O2) for 30 min, and toxicity was determined by the release of lactate dehydrogenase (LDH) 24 h after exposure. The presence of recombinant human ApoE2 (100, 300, or 1000 nM) in the culture media partially protected against oxidative injury. This protection was not reversed by pre-treatment with receptor associated protein. The NMDA receptor antagonist, MK-801, also provided partial protection against H2O2 toxicity. The degree of protection was similar to that conferred by ApoE treatment. The protective effects of ApoE and MK-801 were not additive; no ApoE protection was observed in cultures treated with MK-801 prior to H2O2 exposure. ApoE treatment had no effect on H2O2 stimulated glutamate release, but did increase the rate of glutamate uptake via the high affinity glutamate transporter in H2O2 treated cultures. Pre-treatment with ApoE also conferred partial protection against glutamate-induced LDH release. Taken together, these findings suggest that ApoE protects mixed neuronal-glial cell cultures against irreversible oxidative injury from H2O2 by reducing secondary glutamate excitotoxicity.
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Affiliation(s)
- Yoonki Lee
- Department of Anesthesiology, Multidisciplinary Neuroprotection Laboratories, Duke University Medical Center, Durham, NC 27710, USA
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Aleong R, Aumont N, Dea D, Poirier J. Non-steroidal anti-inflammatory drugs mediate increased in vitro glial expression of apolipoprotein E protein. Eur J Neurosci 2003; 18:1428-38. [PMID: 14511323 DOI: 10.1046/j.1460-9568.2003.02869.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Epidemiological studies have shown that use of non-steroidal anti-inflammatory drugs (NSAIDs) by the elderly is associated with a decreased relative risk and a delayed onset of Alzheimer's disease (AD). In contrast, the apolipoprotein E (apoE) gene has proven to be a risk factor for AD with apoE epsilon 4 AD patients having been found to show lower levels of brain apoE. In the present study, treatment of primary rat mixed glial cell cultures with the common NSAIDs, indomethacin and aspirin, induced significant increases in extracellular apoE protein levels. Similarly, treatment of primary rat astrocyte cell cultures with aspirin and a cyclooxygenase (COX)-2-selective aspirin derivative also stimulated significant increases in apoE protein. However, astrocyte and mixed glial apoE protein levels were significantly reduced following exposure to COX-2-specific indomethacin amides and an inactive indomethacin derivative. ApoE protein modulation was observed at physiological and subphysiological concentrations well below the COX inhibition IC50 values of the NSAIDs used, suggestive of a COX-independent mechanism. In contrast to these results, indomethacin and aspirin treatment failed to induce any significant changes in apoE mRNA levels. The failure of NSAIDs to significantly alter apoE expression may have been indicative of a nontranscriptional mechanism of apoE protein induction. Consequently, NSAID-induced increases in apoE protein may enhance apoE-mediated immunosuppression and compensatory synaptic plasticity, potentially resulting in decreased AD risk and delay of disease onset.
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Affiliation(s)
- Rosanne Aleong
- Douglas Hospital Research Centre, McGill University, Montreal, Quebec, Canada
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Nathoo N, Chetty R, van Dellen JR, Barnett GH. Genetic vulnerability following traumatic brain injury: the role of apolipoprotein E. Mol Pathol 2003; 56:132-6. [PMID: 12782758 PMCID: PMC1187307 DOI: 10.1136/mp.56.3.132] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Apolipoprotein E (APOE) is thought to be responsible for the transportation of lipids within the brain, maintaining structural integrity of the microtubule within the neurone, and assisting with neural transmission. Possession of the APOE epsilon4 allele has also been shown to influence neuropathological findings in patients who die from traumatic brain injury, including the accumulation of amyloid beta protein. Previous clinical studies reporting varying outcome severities of traumatic brain injury, including cognitive and functional recovery, all support the notion that APOE epsilon4 allele possession is associated with an unfavourable outcome. Evidence from experimental and clinical brain injury studies confirms that APOE plays an important role in the response of the brain to injury.
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Affiliation(s)
- N Nathoo
- Department of Neurosurgery, Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, 44195 Ohio, USA.
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Anagnostopoulos AV, Mobraaten LE, Sharp JJ, Davisson MT. Transgenic and knockout databases: behavioral profiles of mouse mutants. Physiol Behav 2001; 73:675-89. [PMID: 11566202 DOI: 10.1016/s0031-9384(01)00525-x] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Genetically engineered strains of mice, modified by transgenesis or gene targeting ("knockouts") are being generated at an impressive rate and used, among other areas, as premiere research tools in deciphering the genetic basis of behavior. As behavioral phenotyping strategies continue to evolve, characterization of these "designer" mice will provide models to evaluate the efficacy of new pharmacological and gene therapy treatments in human hereditary diseases. Reported behavioral profiles include aberrant social, reproductive, and parental behaviors, learning and memory deficits, feeding disorders, aggression, anxiety-related behaviors, pain/analgesia, and altered responses to antidepressants, antipsychotics, ethanol, and psychostimulant drugs of abuse. The Induced Mutant Resource (IMR) at The Jackson Laboratory (TJL, Bar Harbor, ME, USA) imports, cryopreserves, develops, maintains, and distributes biomedically important stocks of transgenic and targeted mutant mice to the research community. Information on neurological/behavioral strains--including behavioral performance, husbandry requirements, strain availability, and genetic typing protocols--is provided through the IMR database (http://www.jax.org/resources/documents/imr/). A catalog of available strains is readily accessible via the JAX Mice website at http://jaxmice.jax.org/index.shtml. In addition, TJL is now host to TBASE (http://tbase.jax.org/), a comprehensive, public-domain database with primary emphasis on mouse knockouts. TBASE contains an exhaustive list of knockout-related citations and provides an extensive phenotypic characterization of numerous behavioral mutants that is extracted directly from the literature. Present efforts to merge the two resources into a novel, schematically enhanced database, provisionally named Transgenic and Targeted Mutation Database (TTMD), will be briefly discussed.
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Arendt T. Alzheimer's disease as a disorder of mechanisms underlying structural brain self-organization. Neuroscience 2001; 102:723-65. [PMID: 11182240 DOI: 10.1016/s0306-4522(00)00516-9] [Citation(s) in RCA: 118] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Mental function has as its cerebral basis a specific dynamic structure. In particular, cortical and limbic areas involved in "higher brain functions" such as learning, memory, perception, self-awareness and consciousness continuously need to be self-adjusted even after development is completed. By this lifelong self-optimization process, the cognitive, behavioural and emotional reactivity of an individual is stepwise remodelled to meet the environmental demands. While the presence of rigid synaptic connections ensures the stability of the principal characteristics of function, the variable configuration of the flexible synaptic connections determines the unique, non-repeatable character of an experienced mental act. With the increasing need during evolution to organize brain structures of increasing complexity, this process of selective dynamic stabilization and destabilization of synaptic connections becomes more and more important. These mechanisms of structural stabilization and labilization underlying a lifelong synaptic remodelling according to experience, are accompanied, however, by increasing inherent possibilities of failure and may, thus, not only allow for the evolutionary acquisition of "higher brain function" but at the same time provide the basis for a variety of neuropsychiatric disorders. It is the objective of the present paper to outline the hypothesis that it might be the disturbance of structural brain self-organization which, based on both genetic and epigenetic information, constantly "creates" and "re-creates" the brain throughout life, that is the defect that underlies Alzheimer's disease (AD). This hypothesis is, in particular, based on the following lines of evidence. (1) AD is a synaptic disorder. (2) AD is associated with aberrant sprouting at both the presynaptic (axonal) and postsynaptic (dendritic) site. (3) The spatial and temporal distribution of AD pathology follows the pattern of structural neuroplasticity in adulthood, which is a developmental pattern. (4) AD pathology preferentially involves molecules critical for the regulation of modifications of synaptic connections, i.e. "morphoregulatory" molecules that are developmentally controlled, such as growth-inducing and growth-associated molecules, synaptic molecules, adhesion molecules, molecules involved in membrane turnover, cytoskeletal proteins, etc. (5) Life events that place an additional burden on the plastic capacity of the brain or that require a particularly high plastic capacity of the brain might trigger the onset of the disease or might stimulate a more rapid progression of the disease. In other words, they might increase the risk for AD in the sense that they determine when, not whether, one gets AD. (6) AD is associated with a reactivation of developmental programmes that are incompatible with a differentiated cellular background and, therefore, lead to neuronal death. From this hypothesis, it can be predicted that a therapeutic intervention into these pathogenetic mechanisms is a particular challenge as it potentially interferes with those mechanisms that at the same time provide the basis for "higher brain function".
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Affiliation(s)
- T Arendt
- Paul Flechsig Institute of Brain Research, Department of Neuroanatomy, University of Leipzig, Jahnallee 59, D-04109, Leipzig, Germany.
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Lominska C, Levin JA, Wang J, Sikes J, Kao C, Smith JD. Apolipoprotein E deficiency effects on learning in mice are dependent upon the background strain. Behav Brain Res 2001; 120:23-34. [PMID: 11173082 DOI: 10.1016/s0166-4328(00)00365-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Apolipoprotein E (apoE) deficient mice were bred onto the C57BL/6 and FVB/N strain backgrounds. The cognitive behavior of food-restricted apoE-deficient and wildtype male mice from these strains was assessed in an olfactory cued 8-arm radial maze. At 6 weeks of age, all four types of mice improved in maze performance over the course of 5 days. However, at 6 months of age, only the apoE-deficient mice on the C57BL/6 background failed to improve their maze performance over the 5 day course, as gauged by the number of incorrect choices made before retrieving both food rewards. Thus, an age-dependent and strain-specific effect of apoE deficiency on cognitive behavior was observed in these mice. The background strain affected activity levels in the maze, as well as in an open field assay. Plasma corticosterone levels were assessed in control, fasted, and post-restraint stress states. Fasting and restraint stress led to increases in plasma corticosterone levels. Although there were strain specific effects on fasting corticosterone levels, and the effect of apoE deficiency on post-stress corticosterone levels, there was no association between fasted corticosterone levels and impaired cognitive behavior in the 8-arm radial maze assay.
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Affiliation(s)
- C Lominska
- The Rockefeller University, Lab. Biochem. Gen. & Metabolism, 1230 York Avenue, New York, NY 10021, USA
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