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Drug pipeline in neurodegeneration based on transgenic mice models of Alzheimer's disease. Ageing Res Rev 2013; 12:116-40. [PMID: 22982398 DOI: 10.1016/j.arr.2012.09.002] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2012] [Revised: 08/31/2012] [Accepted: 09/04/2012] [Indexed: 11/21/2022]
Abstract
Alzheimer's disease (AD) is one of the most important neurodegenerative disorders, bringing about huge medical and social burden in the elderly worldwide. Many aspects of its pathogenesis have remained unclear and no effective treatment exists for it. Within the past 20 years, various mice models harboring AD-related human mutations have been produced. These models imitate diverse AD-related pathologies and have been used for basic and therapeutic investigations in AD. In this regard, there are a wide variety of preclinical trials of potential therapeutic modalities using AD mice models which are of paramount importance for future clinical trials and applications. This review summarizes more than 140 substances and treatment modalities being used in transgenic AD mice models from 2001 to 2011. We also discuss advantages and disadvantages of each model to be used in therapeutic development for AD.
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202
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Morales R, Duran-Aniotz C, Castilla J, Estrada LD, Soto C. De novo induction of amyloid-β deposition in vivo. Mol Psychiatry 2012; 17:1347-53. [PMID: 21968933 DOI: 10.1038/mp.2011.120] [Citation(s) in RCA: 133] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Alzheimer's disease (AD), the most common type of senile dementia, is associated to the build-up of misfolded amyloid-β (Aβ) in the brain. Although compelling evidences indicate that the misfolding and oligomerization of Aβ is the triggering event in AD, the mechanisms responsible for the initiation of Aβ accumulation are unknown. In this study, we show that Aβ deposition can be induced by injection of AD brain extracts into animals, which, without exposure to this material, will never develop these alterations. The accumulation of Aβ deposits increased progressively with the time after inoculation, and the Aβ lesions were observed in brain areas far from the injection site. Our results suggest that some of the typical brain abnormalities associated with AD can be induced by a prion-like mechanism of disease transmission through propagation of protein misfolding. These findings may have broad implications for understanding the molecular mechanisms responsible for the initiation of AD, and may contribute to the development of new strategies for disease prevention and intervention.
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Affiliation(s)
- R Morales
- Mitchell Center for Alzheimer's Disease and Related Brain Disorders, Department of Neurology, University of Texas Houston Medical School, Houston, TX 77030, USA
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203
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Razzaghi-Asl N, Ebadi A, Edraki N, Shahabipour S, Miri R. Ab initio modeling of a potent isophthalamide-based BACE-1 inhibitor: amino acid decomposition analysis. Med Chem Res 2012. [DOI: 10.1007/s00044-012-0277-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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204
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Huang JF, Shang L, Liu P, Zhang MQ, Chen S, Chen D, Fan CL, Wang H, Xiong K. Timosaponin-BII inhibits the up-regulation of BACE1 induced by ferric chloride in rat retina. Altern Ther Health Med 2012; 12:189. [PMID: 23082924 PMCID: PMC3519506 DOI: 10.1186/1472-6882-12-189] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Accepted: 10/18/2012] [Indexed: 11/10/2022]
Abstract
UNLABELLED BACKGROUND Our previous studies indicated that oxidative stress up-regulated the expression of β-amyloid precursor protein cleavage enzyme-1 (BACE1) in rat retina. Pharmacological reports have shown Timosaponin-BII, a purified extract originating from Chinese medical herb Rhizoma Anemarrhenae, is characterized as an antioxidant. Our present study aimed to determine whether Timosaponin-BII affected the expression of BACE1, β-amyloid precursor protein cleavage production of Aβ1-40 and β-C-terminal fragment (β-CTF) in rat retina, which were pre-treated with the oxidizing agent (solution of FeCl₃). RESULTS Few distinctions of BACE1 distribution were observed among all groups (normal control group, model group, Timosaponin-BII treated and vehicle control groups). Rat retinas in model group and vehicle control group manifested an apparent up-regulation of BACE1 expression. Meanwhile, the level of malonaldehyde (MDA), Aβ1-40 and β-CTF were increased. However, when comparing with the vehicle control group, the retinas in Timosaponin-BII treated group showed significantly less BACE1 (p<0.05) and accumulated less Aβ1-40 or β-CTF (p<0.05). It also showed significantly decreased level of MDA (p<0.05) and prolonged partial thromboplastin time (p<0.05). CONCLUSION Our data suggested that Timosaponin-BII remarkably inhibited the up-regulation of BACE1 and reduced the over-production of β-CTF and Aβ in rat retina, which was induced by FeCl₃. The mechanism of Timosaponin-BII on BACE1 expression may be related to its antioxidant property.
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205
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An inverse-Warburg effect and the origin of Alzheimer's disease. Biogerontology 2012; 13:583-94. [PMID: 23086530 DOI: 10.1007/s10522-012-9403-6] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Accepted: 09/28/2012] [Indexed: 02/06/2023]
Abstract
Glycolysis and oxidative phosphorylation (OxPhos) are the two major mechanisms involved in brain energetics. In this article we propose that the sporadic forms of Alzheimer's disease (AD) are driven by age-related damage to macromolecules and organelles which results in the following series of dynamic processes. (1) Metabolic alteration: Upregulation of OxPhos activity by dysfunctional neurons. (2) Natural selection: Competition for the limited energy substrates between neurons with normal OxPhos activity [Type (1)] and dysfunctional neurons with increased OxPhos [Type (2)]. (3) Propagation, due to the fact that Type (1) neurons are outcompeted for limited substrate by Type (2) neurons which, because of increased ROS production, eventually become dysfunctional and die. Otto Warburg, in his studies of the origin of cancer, discovered that most cancer cells are characterized by an increase in glycolytic activity-a property which confers a selective advantage in oncologic environments. Accordingly, we propose the term "inverse-Warburg effect" to describe increased OxPhos activity--a property which we propose confers a selective advantage in neuronal environments, and which we hypothesize to underlie the shift from normal to pathological aging and subsequent AD.
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206
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Ferreira A. Calpain dysregulation in Alzheimer's disease. ISRN BIOCHEMISTRY 2012; 2012:728571. [PMID: 25969760 PMCID: PMC4393001 DOI: 10.5402/2012/728571] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/26/2012] [Accepted: 09/12/2012] [Indexed: 11/23/2022]
Abstract
Alzheimer's disease (AD) is characterized by the presence of senile plaques and neurofibrillary tangles in the neocortex and hippocampus of AD patients. In addition, a marked decrease in synaptic contacts has been detected in these affected brain areas. Due to its prevalence in the aging population, this disease has been the focus of numerous studies. The data obtained from those studies suggest that the mechanisms leading to the formation of the hallmark lesions of AD might be linked. One of such mechanisms seems to be the dysregulation of calcium homeostasis that results in the abnormal activation of calpains. Calpains are a family of Ca(2+)-dependent cysteine proteases that play a key role in multiple cell functions including cell development, differentiation and proliferation, axonal guidance, growth cone motility, and cell death, among others. In this paper, we briefly reviewed data on the structure of these proteases and their regulation under normal conditions. We also summarized data underscoring the participation of calpains in the neurodegenerative mechanisms associated with AD.
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Affiliation(s)
- Adriana Ferreira
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, 303 E. Chicago Avenue, Ward 8-140, Chicago, IL 60611, USA
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207
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Vaccine Development to Treat Alzheimer's Disease Neuropathology in APP/PS1 Transgenic Mice. Int J Alzheimers Dis 2012; 2012:376138. [PMID: 23024882 PMCID: PMC3457670 DOI: 10.1155/2012/376138] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Revised: 06/14/2012] [Accepted: 06/28/2012] [Indexed: 11/17/2022] Open
Abstract
A novel vaccine addressing the major hallmarks of Alzheimer's disease (AD), senile plaque-like deposits of amyloid beta-protein (Aβ), neurofibrillary tangle-like structures, and glial proinflammatory cytokines, has been developed. The present vaccine takes a new approach to circumvent failures of previous ones tested in mice and humans, including the Elan-Wyeth vaccine (AN1792), which caused massive T-cell activation, resulting in a meningoencephalitis-like reaction. The EB101 vaccine consists of Aβ1-42 delivered in a novel immunogen-adjuvant composed of liposomes-containing sphingosine-1-phosphate (S1P). EB101 was administered to APPswe/PS1dE9 transgenic mice before and after AD-like pathological symptoms were detectable. Treatment with EB101 results in a marked reduction of Aβ plaque burden, decrease of neurofibrillary tangle-like structure density, and attenuation of astrocytosis. In this transgenic mouse model, EB101 reduces the basal immunological interaction between the T cells and immune activation markers in the affected hippocampal/cortical areas, consistent with decreased amyloidosis-induced inflammation. Therefore, immunization with EB101 prevents and reverses AD-like neuropathology in a significant manner by halting disease progression without developing behavioral spatial deficits in transgenic mice.
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208
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More SS, Vartak AP, Vince R. The butter flavorant, diacetyl, exacerbates β-amyloid cytotoxicity. Chem Res Toxicol 2012; 25:2083-91. [PMID: 22731744 DOI: 10.1021/tx3001016] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Diacetyl (DA), an ubiquitous butter-flavoring agent, was found to influence several aspects of amyloid-β (Aβ) aggregation--one of the two primary pathologies associated with Alzheimer's disease. Thioflavin T fluorescence and circular dichroism spectroscopic measurements revealed that DA accelerates Aβ¹⁻⁴² aggregation into soluble and ultimately insoluble β-pleated sheet structures. DA was found to covalently bind to Arg⁵ of Aβ¹⁻⁴² through proteolytic digestion-mass spectrometric experiments. These biophysical and chemical effects translated into the potentiation of Aβ¹⁻⁴² cytotoxicity by DA toward SH-SY5Y cells in culture. DA easily traversed through a MDR1-MDCK cell monolayer, an in vitro model of the blood-brain barrier. Additionally, DA was found not only to be resistant to but also inhibitory toward glyoxalase I, the primary initiator of detoxification of amyloid-promoting reactive dicarbonyl species that are generated naturally in large amounts by neuronal tissue. In light of the chronic exposure of industry workers to DA, this study raises the troubling possibility of long-term neurological toxicity mediated by DA.
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Affiliation(s)
- Swati S More
- Center for Drug Design, Academic Health Center, University of Minnesota , 308 Harvard Street SE, 8-123A WDH, Minneapolis, Minnesota 55455, USA
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209
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The phosphodiesterase-4 inhibitor rolipram reverses Aβ-induced cognitive impairment and neuroinflammatory and apoptotic responses in rats. Int J Neuropsychopharmacol 2012; 15:749-66. [PMID: 21733236 DOI: 10.1017/s1461145711000836] [Citation(s) in RCA: 116] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
β-amyloid (Aβ) peptides play an important role in cognition deficits, neuroinflammation, and apoptosis observed in Alzheimer's disease (AD). Activation of cyclic AMP (cAMP) signalling enhances memory and inhibits inflammatory and apoptotic responses. However, it is not known whether inhibition of phosphodiesterase-4 (PDE4), a critical controller of intracellular cAMP concentrations, affects AD-associated neuroinflammatory and apoptotic responses and whether these responses contribute to deficits of memory mediated by cAMP signalling. We addressed these issues using memory tests and neurochemical measures. Specifically, rats microinfused with aggregated Aβ25-35 (10 μg/side) into bilateral CA1 subregions displayed deficits in learning ability and memory, as evidenced by decreases in escape latency during acquisition trials and exploratory activities in the probe trial in the water-maze task and 24-h retention in the passive avoidance test. These effects were reversed by rolipram (0.1, 0.25 and 0.5 mg/kg.d i.p.), a prototypic PDE4 inhibitor, in a dose-dependent manner. Interestingly, Aβ25-35-treated rats also displayed decreases in expression of phosphorylated cAMP response-element binding protein (pCREB) and Bcl-2, but increases in expression of NF-κB p65 and Bax in the hippocampus; these effects were also reversed by rolipram in a dose-dependent manner. Similar neurochemical results were observed by replacing Aβ25-35 with Aβ1-42, a full-length amyloid peptide that quickly forms toxic oligomers. These results suggest that PDE4 inhibitors such as rolipram may reverse Aβ-induced memory deficits at least in part via the attenuation of neuronal inflammation and apoptosis mediated by cAMP/CREB signalling. PDE4 could be a target for treatment of memory loss associated with AD.
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210
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Abstract
Alzheimer's disease (AD) is poised to become the most serious healthcare issue of our generation. The leading theory of AD pathophysiology is the Amyloid Cascade Hypothesis, and clinical trials are now proceeding based on this hypothesis. Here, we review the original evidence for the Amyloid Hypothesis, which was originally focused on the extracellular deposition of beta amyloid peptides (Aβ) in large fibrillar aggregates, as well as how this theory has been extended in recent years to focus on highly toxic small soluble amyloid oligomers. We will also examine emerging evidence that Aβ may actually begin to accumulate intracellularly in lysosomes, and the role for intracellular Aβ and lysosomal dysfunction may play in AD pathophysiology. Finally, we will review the clinical implications of these findings.
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211
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Relation between insulin, insulin-related factors, and plasma amyloid beta peptide levels at midlife in a population-based study. Alzheimer Dis Assoc Disord 2012; 26:50-4. [PMID: 21502851 DOI: 10.1097/wad.0b013e31821764ce] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Little is known regarding factors associated with soluble amyloid beta peptide (Aβ) concentrations in humans at late midlife, when Aβ is likely most critical to Alzheimer disease pathogenesis. We examined the association between insulin, insulin-related factors, and plasma Aβ at late midlife. Plasma Aβ42, Aβ40, fasting insulin, and c-peptide were measured in 468 women without diabetes, aged 59 to 69 years (median 63 y). Before blood draw, participants reported body mass index, waist circumference, physical activity, alcohol intake, hypertension, and diabetes family history. Linear regression was used to calculate age-adjusted mean differences in Aβ42 to Aβ40 ratio, and Aβ42 levels, by insulin and insulin-related factors. The ratio of Aβ42 to Aβ40 was statistically significantly lower in women with family history of diabetes, and Aβ42 was significantly lower with less physical activity, greater waist circumference, hypertension, and family history of diabetes (P<0.05 for all). Aβ42 to Aβ40 ratio, and Aβ42 levels, appeared lower with higher c-peptide levels (P trend=0.07 and 0.06, respectively), although these were not statistically significant. In summary, insulin-related factors appear associated with lower plasma Aβ42 to Aβ40 ratio, and Aβ42, at late midlife, consistent with increased brain sequestration of Aβ42 (relative to Aβ40), suggesting insulin merits focus in strategies to prevent dementia.
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212
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Hamada Y, Nakanishi T, Suzuki K, Yamaguchi R, Hamada T, Hidaka K, Ishiura S, Kiso Y. Novel BACE1 inhibitors possessing a 5-nitroisophthalic scaffold at the P2 position. Bioorg Med Chem Lett 2012; 22:4640-4. [PMID: 22726930 DOI: 10.1016/j.bmcl.2012.05.089] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2012] [Revised: 05/23/2012] [Accepted: 05/24/2012] [Indexed: 11/19/2022]
Abstract
Recently, we reported substrate-based pentapeptidic BACE1 inhibitors possessing a hydroxymethylcarbonyl isostere as a substrate transition-state mimic. These inhibitors showed potent inhibitory activities in enzymatic and cell assays. We also designed and synthesized non-peptidic and small-sized inhibitors possessing a heterocyclic scaffold at the P(2) position. By studying the structure-activity relationship of these inhibitors, we found that the σ-π interaction of an inhibitor with the BACE1-Arg235 side chain played a key role in the inhibition mechanism. Hence, we optimized the inhibitors with a focus on their P(2) regions. In this Letter, a series of novel BACE1 inhibitors possessing a 5-nitroisophthalic scaffold at the P(2) position are described along with the results of the related structure-activity relationship study. These small-sized inhibitors are expected improved membrane permeability and bioavailability.
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Affiliation(s)
- Yoshio Hamada
- Faculty of Pharmaceutical Sciences, Kobe Gakuin University, Minatojima, Chuo-ku, Kobe 650-8586, Japan
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213
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Neuroprotective effect of the aminoestrogen prolame against impairment of learning and memory skills in rats injected with amyloid-β-25–35 into the hippocampus. Eur J Pharmacol 2012; 685:74-80. [DOI: 10.1016/j.ejphar.2012.04.020] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2012] [Revised: 03/23/2012] [Accepted: 04/05/2012] [Indexed: 01/26/2023]
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214
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Pandey LM, Le Denmat S, Delabouglise D, Bruckert F, Pattanayek SK, Weidenhaupt M. Surface chemistry at the nanometer scale influences insulin aggregation. Colloids Surf B Biointerfaces 2012; 100:69-76. [PMID: 22766284 DOI: 10.1016/j.colsurfb.2012.05.022] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2012] [Revised: 04/19/2012] [Accepted: 05/19/2012] [Indexed: 10/28/2022]
Abstract
We synthesized surfaces with different hydrophobicities and roughness by forming self-assembled monolayers (SAMs) of mixed amine and octyl silanes. Insulin aggregation kinetics in the presence of the above surfaces is characterized by a typical lag phase and growth rate. We show that the lag time but not the growth rate varies as a function of the amine fraction on the surface. The amount of adsorbed protein and the adsorption rate during the aggregation process also vary with the amine fraction on the surface and are maximal for equal parts of amine and octyl groups. For all surfaces, the growth phase starts for identical amounts of adsorbed insulin. The initial surface roughness determines the rate at which protein adsorption occurs and hence the time to accumulate enough protein to form aggregation nuclei. In addition, the surface chemistry and topography influence the morphology of aggregates adsorbed on the material surface and the secondary structures of final aggregates released in solution.
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Affiliation(s)
- Lalit M Pandey
- Laboratoire des Matériaux et du Génie Physique (LMGP), Grenoble Institute of Technology, Grenoble, France.
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215
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Protective Effects of Pinostrobin on β-Amyloid-Induced Neurotoxicity in PC12 Cells. Cell Mol Neurobiol 2012; 32:1223-30. [DOI: 10.1007/s10571-012-9847-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2012] [Accepted: 04/16/2012] [Indexed: 12/12/2022]
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216
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Krzyzanowska A, Carro E. Pathological alteration in the choroid plexus of Alzheimer's disease: implication for new therapy approaches. Front Pharmacol 2012; 3:75. [PMID: 22563316 PMCID: PMC3342675 DOI: 10.3389/fphar.2012.00075] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Accepted: 04/10/2012] [Indexed: 01/28/2023] Open
Abstract
Morphological alterations of choroid plexus in Alzheimer’s disease (AD) have been extensively investigated. These changes include epithelial atrophy, thickening of the basement membrane, and stroma fibrosis. As a result, synthesis, secretory, and transportation functions are significantly altered resulting in decreased cerebrospinal fluid (CSF) turnover. Recent studies discuss the potential impacts of these changes, including the possibility of reduced resistance to stress insults and slow clearance of toxic compounds from CSF with specific reference to the amyloid peptide. Here, we review new evidences for AD-related changes in the choroid plexus. The data suggest that the significantly altered functions of the choroid plexus contribute to the multiparametric pathogenesis of late-onset AD.
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Affiliation(s)
- Agnieszka Krzyzanowska
- Neuroscience Group, Instituto de Investigacion Hospital 12 de Octubre (i+12) Madrid, Spain
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217
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Zhu X, Chen C, Ye D, Guan D, Ye L, Jin J, Zhao H, Chen Y, Wang Z, Wang X, Xu Y. Diammonium glycyrrhizinate upregulates PGC-1α and protects against Aβ1-42-induced neurotoxicity. PLoS One 2012; 7:e35823. [PMID: 22540007 PMCID: PMC3335163 DOI: 10.1371/journal.pone.0035823] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2012] [Accepted: 03/22/2012] [Indexed: 11/18/2022] Open
Abstract
Mitochondrial dysfunction is a hallmark of beta-amyloid (Aβ)-induced neurotoxicity in Alzheimer's disease (AD), and is considered an early event in AD pathology. Diammonium glycyrrhizinate (DG), the salt form of Glycyrrhizin, is known for its anti-inflammatory effects, resistance to biologic oxidation and membranous protection. In the present study, the neuroprotective effects of DG on Aβ(1-42)-induced toxicity and its potential mechanisms in primary cortical neurons were investigated. Exposure of neurons to 2 µM Aβ(1-42) resulted in significant viability loss and cell apoptosis. Accumulation of reactive oxygen species (ROS), decreased mitochondrial membrane potential, and activation of caspase-9 and caspase-3 were also observed after Aβ(1-42) exposure. All these effects induced by Aβ(1-42) were markedly reversed by DG treatment. In addition, DG could alleviate lipid peroxidation and partially restore the mitochondrial function in Aβ(1-42)-induced AD mice. DG also significantly increased the PGC-1α expression in vivo and in vitro, while knocking down PGC-1α partially blocked the protective effects, which indicated that PGC-1α contributed to the neuroprotective effects of DG. Furthermore, DG significantly decreased the escape latency and search distance and increased the target crossing times of Aβ(1-42)-induced AD mice in the Morris water maze test. Therefore, these results demonstrated that DG could attenuate Aβ(1-42)-induced neuronal injury by preventing mitochondrial dysfunction and oxidative stress and improved cognitive impairment in Aβ(1-42)-induced AD mice, indicating that DG exerted potential beneficial effects on AD.
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Affiliation(s)
- Xiaolei Zhu
- Department of Neurology, Nanjing Drum Tower Hospital Clinical College of Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, People's Republic of China
- Department of Neurology, Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, People's Republic of China
| | - Cong Chen
- Department of Neurology, Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, People's Republic of China
| | - Dan Ye
- Department of Neurology, Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, People's Republic of China
| | - Dening Guan
- Department of Neurology, Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, People's Republic of China
| | - Lan Ye
- Department of Neurology, Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, People's Republic of China
| | - Jiali Jin
- Department of Neurology, Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, People's Republic of China
| | - Hui Zhao
- Department of Neurology, Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, People's Republic of China
| | - Yanting Chen
- Department of Neurology, Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, People's Republic of China
| | - Zhongyuan Wang
- Department of Neurology, Nanjing Drum Tower Hospital Clinical College of Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, People's Republic of China
- Department of Neurology, Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, People's Republic of China
| | - Xin Wang
- Department of Neurology, Nanjing Drum Tower Hospital Clinical College of Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, People's Republic of China
| | - Yun Xu
- Department of Neurology, Nanjing Drum Tower Hospital Clinical College of Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, People's Republic of China
- Department of Neurology, Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, People's Republic of China
- The State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing, People's Republic of China
- Jiangsu Key Laboratory for Molecular Medicine, Nanjing, People's Republic of China
- * E-mail:
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218
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Nguyen L, Wright S, Lee M, Ren Z, Sauer JM, Hoffman W, Zago W, Kinney GG, Bova MP. Quantifying amyloid beta (Aβ)-mediated changes in neuronal morphology in primary cultures: implications for phenotypic screening. ACTA ACUST UNITED AC 2012; 17:835-42. [PMID: 22473881 DOI: 10.1177/1087057112441972] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Alzheimer's disease (AD) is a devastating neurodegenerative disease affecting millions of people. The amyloid hypothesis suggests that the pathogenesis of AD is related to the accumulation of amyloid beta (Aβ) in the brain. Herein, the authors quantify Aβ-mediated changes in neuronal morphology in primary cultures using the Cellomics neuronal profiling version 3.5 (NPv3.5) BioApplication. We observed that Aβ caused a 33% decrease in neurite length in primary human cortical cultures after 24 h of treatment compared with control-treated cultures. We also determined that quantifying changes of neuronal morphology was a more sensitive indicator of nonlethal cell injury than traditional cytotoxicity assays. Aβ-mediated neuronal deficits observed in human cortical cultures were also observed in primary rat hippocampal cultures, where we demonstrated that the integrin-blocking antibody, 17E6, completely abrogated Aβ-mediated cytotoxicity. Finally, we showed that Aβ challenge to 21 days in vitro rat hippocampal cultures reduced synapsin staining to 14% of control-treated cultures. These results are consistent with the finding that loss of presynaptic integrity is one of the initial deficits observed in AD. The implementation of phenotypic screens to identify compounds that block Aβ-mediated cytotoxicity in primary neuronal cultures may lead to the development of novel strategies to prevent AD.
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Affiliation(s)
- Lan Nguyen
- Elan Pharmaceuticals, Department of Biology, South San Francisco, CA, USA
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219
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Van Dam D, De Deyn PP. Animal models in the drug discovery pipeline for Alzheimer's disease. Br J Pharmacol 2012; 164:1285-300. [PMID: 21371009 DOI: 10.1111/j.1476-5381.2011.01299.x] [Citation(s) in RCA: 152] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
With increasing feasibility of predicting conversion of mild cognitive impairment to dementia based on biomarker profiling, the urgent need for efficacious disease-modifying compounds has become even more critical. Despite intensive research, underlying pathophysiological mechanisms remain insufficiently documented for purposeful target discovery. Translational research based on valid animal models may aid in alleviating some of the unmet needs in the current Alzheimer's disease pharmaceutical market, which includes disease-modification, increased efficacy and safety, reduction of the number of treatment unresponsive patients and patient compliance. The development and phenotyping of animal models is indeed essential in Alzheimer's disease-related research as valid models enable the appraisal of early pathological processes - which are often not accessible in patients, and subsequent target discovery and evaluation. This review paper summarizes and critically evaluates currently available animal models, and discusses their value to the Alzheimer drug discovery pipeline. Models dealt with include spontaneous models in various species, including senescence-accelerated mice, chemical and lesion-induced rodent models, and genetically modified models developed in Drosophila melanogaster, Caenorhabditis elegans, Danio rerio and rodents. Although highly valid animal models exist, none of the currently available models recapitulates all aspects of human Alzheimer's disease, and one should always be aware of the potential dangers of uncritical extrapolating from model organisms to a human condition that takes decades to develop and mainly involves higher cognitive functions.
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Affiliation(s)
- Debby Van Dam
- Laboratory of Neurochemistry & Behaviour, Institute Born-Bunge, Department of Biomedical Sciences, University of Antwerp, Wilrijk (Antwerp), Belgium.
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220
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Xue S, Chen C, Dong W, Hui G, Liu T, Guo L. Therapeutic effects of human amniotic epithelial cell transplantation on double-transgenic mice co-expressing APPswe and PS1ΔE9-deleted genes. SCIENCE CHINA-LIFE SCIENCES 2012; 55:132-40. [PMID: 22415684 DOI: 10.1007/s11427-012-4283-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2011] [Accepted: 11/27/2011] [Indexed: 10/28/2022]
Abstract
Human amniotic epithelial cells (HAECs), which exhibit characteristics of embryonic and pluripotent stem cells, could be utilized for cell therapy without legal or ethical problems. Double-transgenic (TG) mice (n=20) and wild-type (WT) mice (n=20) were randomly assigned to two groups, respectively. The transplantation group was treated with HAECs and the control group with PBS. A six-radial arm water maze was used to assess spatial memory. Immunofluorescence was utilized to track HAEC survival. Immunohistochemistry was used to determine octamer-binding protein 4 (oct-4) and nanog expression in the HAECs. High-performance liquid chromatography (HPLC) was used to measure acetylcholine levels in the hippocampus. The density of cholinergic neurons in the basal forebrain and nerve fibers in the hippocampus was measured following acetylcholinesterase staining. Results showed that transplanted HAECs survived for at least eight weeks and migrated to the third ventricle without immune rejection. Graft HAECs also expressed the specific stem cell markers oct-4 and nanog. Compared with the control group, HAEC transplantation significantly ameliorated spatial memory deficits in TG mice, as well as increased acetylcholine levels and the number of hippocampal cholinergic neurites. Intracerebroventricular HAEC transplantation improved spatial memory in double-TG mice, and results suggested that increased acetylcholine levels in the hippocampus, released by surviving cholinergic neurites, were responsible for this improvement.
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Affiliation(s)
- Shouru Xue
- Department of Neurology, First Affiliated Hospital of Soochow University, Suzhou 215006, China
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221
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Jones EM, Dubey M, Camp PJ, Vernon BC, Biernat J, Mandelkow E, Majewski J, Chi EY. Interaction of tau protein with model lipid membranes induces tau structural compaction and membrane disruption. Biochemistry 2012; 51:2539-50. [PMID: 22401494 DOI: 10.1021/bi201857v] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The misfolding and aggregation of the intrinsically disordered, microtubule-associated tau protein into neurofibrillary tangles is implicated in the pathogenesis of Alzheimer's disease. However, the mechanisms of tau aggregation and toxicity remain unknown. Recent work has shown that anionic lipid membranes can induce tau aggregation and that membrane permeabilization may serve as a pathway by which protein aggregates exert toxicity, suggesting that the plasma membrane may play dual roles in tau pathology. This prompted our investigation to assess tau's propensity to interact with membranes and to elucidate the mutually disruptive structural perturbations the interactions induce in both tau and the membrane. We show that although highly charged and soluble, the full-length tau (hTau40) is also highly surface active, selectively inserts into anionic DMPG lipid monolayers and induces membrane morphological changes. To resolve molecular-scale structural details of hTau40 associated with lipid membranes, X-ray and neutron scattering techniques are utilized. X-ray reflectivity indicates hTau40s presence underneath a DMPG monolayer and penetration into the lipid headgroups and tailgroups, whereas grazing incidence X-ray diffraction shows that hTau40 insertion disrupts lipid packing. Moreover, both air/water and DMPG lipid membrane interfaces induce the disordered hTau40 to partially adopt a more compact conformation with density similar to that of a folded protein. Neutron reflectivity shows that tau completely disrupts supported DMPG bilayers while leaving the neutral DPPC bilayer intact. Our results show that hTau40s strong interaction with anionic lipids induces tau structural compaction and membrane disruption, suggesting possible membrane-based mechanisms of tau aggregation and toxicity in neurodegenerative diseases.
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Affiliation(s)
- Emmalee M Jones
- Department of Chemical and Nuclear Engineering, Center for Biomedical Engineering, University of New Mexico, Albuquerque, New Mexico 87131, United States
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222
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Merlo S, Sortino MA. Estrogen activates matrix metalloproteinases-2 and -9 to increase beta amyloid degradation. Mol Cell Neurosci 2012; 49:423-9. [PMID: 22402435 DOI: 10.1016/j.mcn.2012.02.005] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2011] [Revised: 01/30/2012] [Accepted: 02/15/2012] [Indexed: 01/04/2023] Open
Abstract
Estrogen is known to affect different aspects of β-amyloid (Aβ) synthesis and degradation. The present work was undertaken to evaluate specifically whether matrix metalloproteinases (MMP) -2 and -9 are involved in Aβ degradation induced by estrogen and whether this is relevant to estrogen-induced neuroprotection. In SH-SY5Y human neuroblastoma cells, 10 nM 17β-estradiol (17β-E2) increases mRNA and intracellular protein expression of MMP-2 and -9, as well as the levels of the active forms of both enzymes released in the medium. Specificity of the effect is proved by prevention with the estrogen receptor (ER) antagonist ICI 182,780 (1 μM) and involvement of the ERα subtype is confirmed by the use of selective ERα or ERβ agonists (PPT, DPN) and antagonists (MPP, PHTPP). 17β-E2 significantly increases the degradation of Aβ, either transferred with the conditioned medium of H4-APPSw human neuroglioma cells, engineered to overproduce Aβ(1-40) and Aβ(1-42), or exogenously added as 2 μM Aβ(1-42). Both these effects are completely prevented by preexposure to the broad spectrum MMP inhibitor GM6001 (5 μM). Importantly, the 17β-E2-induced rescue of neuroblastoma cells challenged with 2 μM Aβ(1-42), an effect prevented by ICI 182,780 (1 μM), is mediated by MMPs, as it appears significantly reduced by GM6001 (5 μM) as well as by both MMP-2 (200 nM) and MMP-9 (200nM) selective inhibitors. In conclusion, the present study shows for the first time that MMP-2 and -9 give a main contribution to estrogen's neuroprotective effect.
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Affiliation(s)
- Sara Merlo
- Department of Clinical and Molecular Biomedicine, section of Pharmacology and Biochemistry, University of Catania, Catania, Italy
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223
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Kameshima N, Nanjou T, Fukuhara T, Yanagisawa D, Tooyama I. Correlation of Aβ deposition in the nasal cavity with the formation of senile plaques in the brain of a transgenic mouse model of Alzheimer's disease. Neurosci Lett 2012; 513:166-9. [PMID: 22343315 DOI: 10.1016/j.neulet.2012.02.026] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2011] [Revised: 01/18/2012] [Accepted: 02/08/2012] [Indexed: 01/02/2023]
Abstract
The deposition of β-amyloid peptides (Aβ) is commonly reported in the nasal cavity of Alzheimer's disease (AD) patients, although the pathological significance of this finding is unknown. This study compared Aβ concentrations in the nasal area with those in the brain, blood, and cerebrospinal fluid, respectively. Immunohistochemical analysis identified Aβ deposits in the nasal epithelium of Tg2576 mice. Enzyme-linked immunosorbent assay measurements revealed a correlation between the content of Aβ42 in the nasal area and that in the brain, but not with that in the blood. These results suggest that the highly accessible nasal cavity could be a useful site for diagnostic analysis of AD based on Aβ content.
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Affiliation(s)
- Naoko Kameshima
- Molecular Neuroscience Research Center, Shiga University of Medical Science, Seta Tsukinowa-cho, Otsu 520-2192, Japan
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224
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The effect of ageing on neurogenesis and oxidative stress in the APP(swe)/PS1(deltaE9) mouse model of Alzheimer's disease. Brain Res 2012; 1449:83-93. [PMID: 22418058 DOI: 10.1016/j.brainres.2012.02.015] [Citation(s) in RCA: 104] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2011] [Revised: 01/29/2012] [Accepted: 02/06/2012] [Indexed: 01/23/2023]
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterised by memory loss and impaired cognitive function. One of the hallmarks of AD is the formation of beta amyloid (Aβ) plaques. Aβ has neurodegenerative properties and aggregates in the brain, causing inflammation, oxidative stress and eventually neuronal loss. In AD, adult neurogenesis in the dentate gyrus (DG) of the hippocampus is known to be impaired. We tested how ageing affects neurogenesis and oxidative stress in the commonly used APP(SWE)/PS1(ΔE9) mouse model of AD and their wild type (wt) littermate controls aged 3, 5, 10 and 15months. Progenitor cell proliferation in the DG of APP/PS1 was lower at 3, 5 and 10months compared to controls, while oxidative stress in APP/PS1 mice was increased in the cortex at 3 and 5months of age compared to controls. The numbers of new neurons in the DG were decreased in APP/PS1 mice at 10 and 15months. In APP/PS1 mice, Aβ plaques were evident in the cortex from 3months onward; however these were small and few. Plaque size and number consistently increased with age in APP/PS1 mice. These results show that the damage to the brain occurs already very early in the brain, and although neurogenesis is impaired, it is still active even in late stage AD. Therefore, therapies would have the best effects if started early, but promoting neurogenesis may act in a protective and reconstructive way even in later stages of AD.
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225
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Wentzell JS, Bolkan BJ, Carmine-Simmen K, Swanson TL, Musashe DT, Kretzschmar D. Amyloid precursor proteins are protective in Drosophila models of progressive neurodegeneration. Neurobiol Dis 2012; 46:78-87. [PMID: 22266106 DOI: 10.1016/j.nbd.2011.12.047] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2011] [Revised: 12/06/2011] [Accepted: 12/31/2011] [Indexed: 12/11/2022] Open
Abstract
The processing of Amyloid Precursor Proteins (APPs) results in several fragments, including soluble N-terminal ectodomains (sAPPs) and C-terminal intracellular domains (AICD). sAPPs have been ascribed neurotrophic or neuroprotective functions in cell culture, although β-cleaved sAPPs can have deleterious effects and trigger neuronal cell death. Here we describe a neuroproprotective function of APP and fly APPL (Amyloid Precursor Protein-like) in vivo in several Drosophila mutants with progressive neurodegeneration. We show that expression of the N-terminal ectodomain is sufficient to suppress the progressive degeneration in these mutants and that the secretion of the ectodomain is required for this function. In addition, a protective effect is achieved by expressing kuzbanian (which has α-secretase activity) whereas expression of fly and human BACE aggravates the phenotypes, suggesting that the protective function is specifically mediated by the α-cleaved ectodomain. Furthermore, genetic and molecular studies suggest that the N-terminal fragments interact with full-length APPL activating a downstream signaling pathway via the AICD. Because we show protective effects in mutants that affect different genes (AMP-activated protein kinase, MAP1b, rasGAP), we propose that the protective effect is not due to a genetic interaction between APPL and these genes but a more general aspect of APP proteins. The result that APP proteins and specifically their soluble α-cleaved ectodomains can protect against progressive neurodegeneration in vivo provides support for the hypothesis that a disruption of the physiological function of APP could play a role in the pathogenesis of Alzheimer's Disease.
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Affiliation(s)
- Jill S Wentzell
- Center for Research on Occupational and Environmental Toxicology, Oregon Health & Sciences University, Portland, OR 97239, USA
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226
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Synaptic dysfunction in Alzheimer's disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 970:573-601. [PMID: 22351073 DOI: 10.1007/978-3-7091-0932-8_25] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Generation of amyloid peptide (Aβ) is at the beginning of a cascade that leads to Alzheimer's disease (AD). Amyloid precursor protein (APP), as well as β- and γ-secretases, is the principal player involved in Aβ production, while α-secretase cleavage on APP prevents Aβ deposition. Recent studies suggested that soluble assembly states of Aβ peptides can cause cognitive problems by disrupting synaptic function in the absence of significant neurodegeneration. Therefore, current research investigates the relative importance of these various soluble Aβ assemblies in causing synaptic dysfunction and cognitive deficits. Several Aβ oligomers targets and cellular mechanisms responsible of Aβ-induced synaptic failure have been identified. The first and most important mechanism impugns a toxic gain of function for Aβ which results due to self-association and attainment of new structures capable of novel interactions that lead to impaired plasticity. Other scenarios predicate that Aβ has a normal physiological role. On the one hand, insufficient Aβ could lead to a loss of normal function, whereas excess Aβ may precipitate dysfunction. How this occurs and which the main target/s is/are for the synaptic action of Aβ remains to be fully understood and would certainly represent one of the main challenges to future AD research.
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227
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Mulder SD, Veerhuis R, Blankenstein MA, Nielsen HM. The effect of amyloid associated proteins on the expression of genes involved in amyloid-β clearance by adult human astrocytes. Exp Neurol 2012; 233:373-9. [DOI: 10.1016/j.expneurol.2011.11.001] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2011] [Revised: 10/25/2011] [Accepted: 11/01/2011] [Indexed: 11/24/2022]
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228
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Massaad CA. Neuronal and vascular oxidative stress in Alzheimer's disease. Curr Neuropharmacol 2011; 9:662-73. [PMID: 22654724 PMCID: PMC3263460 DOI: 10.2174/157015911798376244] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2010] [Revised: 10/06/2010] [Accepted: 10/11/2010] [Indexed: 01/22/2023] Open
Abstract
The brain is a highly metabolically active organ producing large amounts of reactive oxygen species (ROS). These ROS are kept in check by an elaborate network of antioxidants. Although ROS are necessary for signaling and synaptic plasticity, their uncontrolled levels cause oxidation of essential macromolecules such as membrane lipids, nucleic acids, enzymes and cytoskeletal proteins. Indeed, overproduction of ROS and/or failure of the antioxidant network lead to neuronal oxidative stress, a condition associated with not only aging but also Alzheimer's disease (AD). However, the specific source of excessive ROS production has not yet been identified. On one hand, amyloid beta (Aβ) has been extensively shown to act as an oxidant molecule. On the other hand, oxidative stress has been shown to precede and exacerbate Aβ pathology. This review will address the involvement of oxidative stress in the context of neuronal as well as vascular dysfunction associated with AD.
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Affiliation(s)
- Cynthia A Massaad
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas, USA
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229
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Li X, Buxbaum JN. Transthyretin and the brain re-visited: is neuronal synthesis of transthyretin protective in Alzheimer's disease? Mol Neurodegener 2011; 6:79. [PMID: 22112803 PMCID: PMC3267701 DOI: 10.1186/1750-1326-6-79] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2011] [Accepted: 11/23/2011] [Indexed: 12/14/2022] Open
Abstract
Since the mid-1990's a trickle of publications from scattered independent laboratories have presented data suggesting that the systemic amyloid precursor transthyretin (TTR) could interact with the amyloidogenic β-amyloid (Aβ) peptide of Alzheimer's disease (AD). The notion that one amyloid precursor could actually inhibit amyloid fibril formation by another seemed quite far-fetched. Further it seemed clear that within the CNS, TTR was only produced in choroid plexus epithelial cells, not in neurons. The most enthusiastic of the authors proclaimed that TTR sequestered Aβ in vivo resulting in a lowered TTR level in the cerebrospinal fluid (CSF) of AD patients and that the relationship was salutary. More circumspect investigators merely showed in vitro interaction between the two molecules. A single in vivo study in Caenorhabditis elegans suggested that wild type human TTR could suppress the abnormalities seen when Aβ was expressed in the muscle cells of the worm. Subsequent studies in human Aβ transgenic mice, including those from our laboratory, also suggested that the interaction reduced the Aβ deposition phenotype. We have reviewed the literature analyzing the relationship including recent data examining potential mechanisms that could explain the effect. We have proposed a model which is consistent with most of the published data and current notions of AD pathogenesis and can serve as a hypothesis which can be tested.
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Affiliation(s)
- Xinyi Li
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, 10550 North Torrey Pines Rd,, MEM-230, La Jolla, CA 92037, USA
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230
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Sierks MR, Chatterjee G, McGraw C, Kasturirangan S, Schulz P, Prasad S. CSF levels of oligomeric alpha-synuclein and beta-amyloid as biomarkers for neurodegenerative disease. Integr Biol (Camb) 2011; 3:1188-96. [PMID: 22076255 DOI: 10.1039/c1ib00018g] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Protein misfolding and aggregation is a critically important feature in many devastating neurodegenerative diseases, therefore characterization of the CSF concentration profiles of selected key forms and morphologies of proteins involved in these diseases, including β-amyloid (Aβ) and α-synuclein (a-syn), can be an effective diagnostic assay for these diseases. CSF levels of tau and Aβ have been shown to have great promise as biomarkers for Alzheimer's disease. However since the onset and progression of many neurodegenerative diseases have been strongly correlated with the presence of soluble oligomeric aggregates of proteins including various Aβ and a-syn aggregate species, specific detection and quantification of levels of each of these different toxic protein species in CSF may provide a simple and accurate means to presymptomatically diagnose and distinguish between these diseases. Here we show that the presence of different protein morphologies in human CSF samples can be readily detected using highly selective morphology specific reagents in conjunction with a sensitive electronic biosensor. We further show that these morphology specific reagents can readily distinguish between post-mortem CSF samples from AD, PD and cognitively normal sources. These studies suggest that detection of specific oligomeric aggregate species holds great promise as sensitive biomarkers for neurodegenerative disease.
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Affiliation(s)
- Michael R Sierks
- Department of Chemical Engineering, Box 876106, Arizona State University, Tempe, AZ 85287, USA.
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231
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Position paper of the Italian Society for the study of Dementias (Sindem) on the proposal of a new Lexicon on Alzheimer disease. Neurol Sci 2011; 33:201-8. [DOI: 10.1007/s10072-011-0825-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2011] [Accepted: 10/07/2011] [Indexed: 01/08/2023]
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232
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Zhao L, Yao J, Mao Z, Chen S, Wang Y, Brinton RD. 17β-Estradiol regulates insulin-degrading enzyme expression via an ERβ/PI3-K pathway in hippocampus: relevance to Alzheimer's prevention. Neurobiol Aging 2011; 32:1949-63. [PMID: 20053478 PMCID: PMC2889185 DOI: 10.1016/j.neurobiolaging.2009.12.010] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2009] [Revised: 11/13/2009] [Accepted: 12/11/2009] [Indexed: 01/11/2023]
Abstract
Insulin-degrading enzyme (IDE), an enzyme that primarily degrades insulin, has recently been demonstrated to play a significant role in the catabolism of amyloid β (Aβ) protein in the brain. Reduced IDE expression and/or activity have been associated with the etiology and development of Alzheimer's disease (AD). Using three model systems, the present investigation provides the first documentation indicating that estrogen robustly regulates the expression of IDE in normal, menopausal and early-stage AD brains. In vitro analyses in primary cultures of rat hippocampal neurons revealed that 17β-estradiol (17β-E2) increased IDE in both mRNA and protein levels in a time-dependent manner. Further pharmacological analyses indicated that 17β-E2-induced IDE expression was dependent upon estrogen receptor (ER) β and required activation of phosphatidylinositol 3-kinase (PI3-K). In vivo analyses in adult female rats revealed a brain region-specific responsive profile. Ovariectomy (OVX) induced a significant decline in IDE expression in the hippocampus, which was prevented by 17β-E2. Neither OVX nor 17β-E2 affected IDE expression in the cerebellum. In vivo analyses in triple transgenic AD (3xTg-AD) female mice revealed an inverse correlation between the age-related increase in Aβ load and the decrease in IDE expression in the hippocampal formation. Treatment with 17β-E2 attenuated Aβ accumulation/plaque formation and elevated hippocampal IDE expression in 12-month-old 3xTg-AD OVX mice. Collectively, these findings indicate that 17β-E2 regulates IDE expression in a brain region-specific manner and such a regulatory role in the hippocampus, mediated by an ERβ/PI3-K pathway, could serve as a direct mechanism underlying estrogen-mediated preventative effect against AD when initiated at the onset of menopause.
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Affiliation(s)
- Liqin Zhao
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA 90033, United States
| | - Jia Yao
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA 90033, United States
| | - Zisu Mao
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA 90033, United States
| | - Shuhua Chen
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA 90033, United States
| | - Yan Wang
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA 90033, United States
| | - Roberta Diaz Brinton
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA 90033, United States
- Program in Neuroscience, University of Southern California, Los Angeles, CA 90033, United States
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233
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Protective Effect of Isorhynchophylline Against β-Amyloid-Induced Neurotoxicity in PC12 Cells. Cell Mol Neurobiol 2011; 32:353-60. [DOI: 10.1007/s10571-011-9763-5] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2011] [Accepted: 10/10/2011] [Indexed: 12/25/2022]
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234
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Resmi V, Ambika G, Amritkar RE. General mechanism for amplitude death in coupled systems. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2011; 84:046212. [PMID: 22181250 DOI: 10.1103/physreve.84.046212] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2011] [Revised: 09/05/2011] [Indexed: 05/31/2023]
Abstract
We introduce a general mechanism for amplitude death in coupled synchronizable dynamical systems. It is known that when two systems are coupled directly, they can synchronize under suitable conditions. When an indirect feedback coupling through an environment or an external system is introduced in them, it is found to induce a tendency for antisynchronization. We show that, for sufficient strengths, these two competing effects can lead to amplitude death. We provide a general stability analysis that gives the threshold values for onset of amplitude death. We study in detail the nature of the transition to death in several specific cases and find that the transitions can be of two types--continuous and discontinuous. By choosing a variety of dynamics, for example, periodic, chaotic, hyperchaotic, and time-delay systems, we illustrate that this mechanism is quite general and works for different types of direct coupling, such as diffusive, replacement, and synaptic couplings, and for different damped dynamics of the environment.
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Affiliation(s)
- V Resmi
- Indian Institute of Science Education and Research, Pune 411021, India.
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235
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Li J, Sheng W, Feng C, Zuo Z. Pyrrolidine dithiocarbamate attenuates brain Aβ increase and improves long-term neurological outcome in rats after transient focal brain ischemia. Neurobiol Dis 2011; 45:564-72. [PMID: 21983158 DOI: 10.1016/j.nbd.2011.09.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2011] [Revised: 08/23/2011] [Accepted: 09/16/2011] [Indexed: 12/12/2022] Open
Abstract
Evidence suggests an association between brain ischemia and Alzheimer's disease (AD) development. Amyloid plaques consisted of β-amyloid peptide (Aβ) in the brain are a pathological hallmark of AD. Little is known about how brain ischemia induces AD-like neuropathology. A strategy effective to block such brain changes has not been reported. Here, adult male Sprague-Dawley rats were subjected to a 90-min right middle cerebral artery occlusion (MCAO). Pyrrolidine dithiocarbamate (PDTC) at various doses was given daily via gastric gavage with the first dose given at 10 min after the onset of reperfusion. The MCAO increased Aβ1-42 concentrations in the ischemic brain tissues. PDTC attenuated this increase. PDTC also decreased the ischemia-reduced expression of neprilysin, an Aβ degrading enzyme. Aβ1-42 levels were negatively correlated with neprilysin protein abundance. Brain ischemia decreased the expression of β-amyloid converting enzyme 1, a key enzyme to produce Aβ, and increased the expression of insulin-degrading enzyme, another Aβ degrading enzyme. Animals had impaired learning and memory at 2 months after the MCAO. PDTC attenuated this impairment. PDTC also improved long-term neurological outcomes. Our findings suggest that PDTC improves long-term neurological outcome of rats after transient focal brain ischemia. PDTC reduces ischemia-induced Aβ accumulation, possibly via preserving neprilysin expression.
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Affiliation(s)
- Jiejie Li
- Department of Anesthesiology, University of Virginia, Charlottesville, VA 22908, USA
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236
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Α-mangostin, a polyphenolic xanthone derivative from mangosteen, attenuates β-amyloid oligomers-induced neurotoxicity by inhibiting amyloid aggregation. Neuropharmacology 2011; 62:871-81. [PMID: 21958557 DOI: 10.1016/j.neuropharm.2011.09.016] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2011] [Revised: 08/21/2011] [Accepted: 09/14/2011] [Indexed: 12/25/2022]
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disease characterized by the accumulation of β-sheet-rich amyloid oligomers or fibrils which are associated with cellular toxicity in the brain. Inhibition of Aβ aggregation could be a viable therapeutic strategy for slowing and/or preventing the progress of AD. Here we reported that α-mangostin (α-M), a polyphenolic xanthone derivative from mangosteen, concentration-dependently attenuated the neurotoxicity induced by Aβ-(1-40) or Aβ-(1-42) oligomers (EC(50) = 3.89 nM, 4.14 nM respectively) as observed by decreased cell viability and impaired neurite outgrowth in primary rat cerebral cortical neurons. Molecular docking and dynamics simulations demonstrated that α-M could potentially bind to Aβ and stabilize α-helical conformation. α-M was found to directly dissociate Aβ-(1-40) and Aβ-(1-42) oligomers by blotting with oligomer-specific antibodies. ThioflavinT fluorescence assay and electron microscopy imaging further demonstrated that α-M blocked the fibril formation as well as disturbed the pre-formed fibrils. Taken together, our results indicate that α-M is capable to inhibit and dissociate the Aβ aggregation, which could contribute to its effect of attenuating Aβ oligomers-induced neurotoxicity. Thus, α-M could be a great potential candidate for AD treatment. This article is part of a Special Issue entitled 'Post-Traumatic Stress Disorder'.
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237
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Yousefi BH, Drzezga A, von Reutern B, Manook A, Schwaiger M, Wester HJ, Henriksen G. A Novel (18)F-Labeled Imidazo[2,1-b]benzothiazole (IBT) for High-Contrast PET Imaging of β-Amyloid Plaques. ACS Med Chem Lett 2011; 2:673-7. [PMID: 24900362 DOI: 10.1021/ml200123w] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2011] [Accepted: 07/19/2011] [Indexed: 12/11/2022] Open
Abstract
(18)F-labeled imidazo[2,1-b]benzothiazole ([(18)F]8) was synthesized and evaluated as a tracer for cerebral β-amyloid deposits (Aβ) by means of positron emission tomography (PET). [(18)F]8 exhibits a high affinity to Aβ and suitable brain uptake kinetics combined with a high metabolic stability in the brain. In a double transgenic APP/PS1 mouse model of Alzheimer's disease, we demonstrated a specific uptake of [(18)F]8 in Aβ-containing telencephalic brain regions. The specific binding of [(18)F]8 to Aβ was confirmed by regional brain biodistribution and autoradiography and correlated to immunohistochemistry staining. Analysis of brain sections of APP/PS1 mouse injected with a cocktail of [(18)F]8 and reference compound [(3)H]PiB revealed that the two tracers bind to Aβ plaques in the brain of mouse in a comparable binding pattern. [(18)F]8 represents the first high-contrast PET imaging agent for detection of Aβ plaques in transgenic mouse model of Alzheimer's disease and holds promise for transfer to a clinical evaluation.
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Affiliation(s)
- Behrooz H. Yousefi
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technische Universität München, Ismaninger
Strasse 22, 81675 München, Germany
| | - Alexander Drzezga
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technische Universität München, Ismaninger
Strasse 22, 81675 München, Germany
| | - Boris von Reutern
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technische Universität München, Ismaninger
Strasse 22, 81675 München, Germany
| | - André Manook
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technische Universität München, Ismaninger
Strasse 22, 81675 München, Germany
| | - Markus Schwaiger
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technische Universität München, Ismaninger
Strasse 22, 81675 München, Germany
| | - Hans-Jürgen Wester
- Lehrstuhl für Pharmazeutische Radiochemie, Walther-Meissner-Strasse 3, 85748 Garching,
Germany
| | - Gjermund Henriksen
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technische Universität München, Ismaninger
Strasse 22, 81675 München, Germany
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238
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Expression, purification, and reconstitution of the transmembrane domain of the human amyloid precursor protein for NMR studies. Protein Expr Purif 2011; 81:11-17. [PMID: 21907289 DOI: 10.1016/j.pep.2011.08.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2011] [Revised: 08/08/2011] [Accepted: 08/09/2011] [Indexed: 12/31/2022]
Abstract
Alzheimer's disease (AD) is the most common type of dementia in elderly people. Senile plaques, a pathologic hallmark of AD, are composed of amyloid β peptide (Aβ). Aβ aggregation produces toxic oligomers and fibrils, causing neuronal dysfunction and memory loss. Aβ is generated from two sequential proteolytic cleavages of a membrane protein, amyloid precursor protein (APP), by β- and γ-secretases. The transmembrane (TM) domain of APP, APPTM, is the substrate of γ-secretase for Aβ production. The interaction between APPTM and γ-secretase determines the production of different species of Aβ. Although numerous experimental and theoretical studies of APPTM structure exist, experimental 3D structure of APPTM has not been obtained at atomic resolution. Using the pETM41 vector, we successfully expressed an MBP-APPTM fusion protein. By combining Ni-NTA chromatography, TEV protease cleavage, and reverse phase HPLC (RP-HPLC), we purified isotopically-labeled APPTM for NMR studies. The reconstitution of APPTM into micelles yielded high quality 2D (15)N-(1)H HSQC spectra. This reliable method for APPTM expression and purification lays a good foundation for future structural studies of APPTM using NMR.
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239
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Jo MR, Park MH, Choi DY, Yuk DY, Lee YM, Lee JM, Jeong JH, Oh KW, Lee MS, Han SB, Hong JT. Neuroprotective Effect of L-Theanine on Aβ-Induced Neurotoxicity through Anti-Oxidative Mechanisms in SK-N-SH and SK-N-MC Cells. Biomol Ther (Seoul) 2011. [DOI: 10.4062/biomolther.2011.19.3.288] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
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240
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Williams TL, Serpell LC. Membrane and surface interactions of Alzheimer’s Aβ peptide - insights into the mechanism of cytotoxicity. FEBS J 2011; 278:3905-17. [DOI: 10.1111/j.1742-4658.2011.08228.x] [Citation(s) in RCA: 275] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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241
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Sokolowski JD, Mandell JW. Phagocytic clearance in neurodegeneration. THE AMERICAN JOURNAL OF PATHOLOGY 2011; 178:1416-28. [PMID: 21435432 DOI: 10.1016/j.ajpath.2010.12.051] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2010] [Revised: 12/15/2010] [Accepted: 12/22/2010] [Indexed: 12/14/2022]
Abstract
The cellular and molecular mechanisms of phagocytic clearance of apoptotic cells and debris have been intensely studied in invertebrate model organisms and in the mammalian immune system. This evolutionarily conserved process serves multiple purposes. Uncleared debris from dying cells or aggregated proteins can be toxic and may trigger exaggerated inflammatory responses. Even though apoptotic cell death and debris accumulation are key features of neurodegenerative diseases, relatively little attention has been paid to this important homeostatic function in the central nervous system (CNS). This review attempts to summarize our knowledge of phagocytic clearance in the CNS, with a focus on retinal degeneration, forms of which are caused by mutations in genes within known phagocytic pathways, and on Alzheimer's disease (AD). Interest in phagocytic clearance mechanisms in AD was stimulated by the discovery that immunization could promote phagocytic clearance of amyloid-β; however, much less is known about clearance of neuronal and synaptic corpses in AD and other neurodegenerative diseases. Because the regulation of phagocytic activity is intertwined with cytokine signaling, this review also addresses the relationships among CNS inflammation, glial responses, and phagocytic clearance.
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Affiliation(s)
- Jennifer D Sokolowski
- Department of Pathology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
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242
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Pascale CL, Miller MC, Chiu C, Boylan M, Caralopoulos IN, Gonzalez L, Johanson CE, Silverberg GD. Amyloid-beta transporter expression at the blood-CSF barrier is age-dependent. Fluids Barriers CNS 2011; 8:21. [PMID: 21740544 PMCID: PMC3162580 DOI: 10.1186/2045-8118-8-21] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2011] [Accepted: 07/08/2011] [Indexed: 02/08/2023] Open
Abstract
Background Age is the major risk factor for many neurodegenerative diseases, including Alzheimer's disease (AD). There is an accumulation of amyloid-beta peptides (Aβ) in both the AD brain and the normal aging brain. Clearance of Aβ from the brain occurs via active transport at the blood-brain barrier (BBB) and blood-cerebrospinal fluid barrier (BCSFB). With increasing age, the expression of the Aβ efflux transporters is decreased and the Aβ influx transporter expression is increased at the BBB, adding to the amyloid burden in the brain. Expression of the Aβ transporters at the choroid plexus (CP) epithelium as a function of aging was the subject of this study. Methods This project investigated the changes in expression of the Aβ transporters, the low density lipoprotein receptor-related protein-1 (LRP-1), P-glycoprotein (P-gp), LRP-2 (megalin) and the receptor for advanced glycation end-products (RAGE) at the BCSFB in Brown-Norway/Fischer rats at ages 3, 6, 9, 12, 20, 30 and 36 months, using real time RT-PCR to measure transporter mRNA expression, and immunohistochemistry (IHC) to measure transporter protein in isolated rat CP. Results There was an increase in the transcription of the Aβ efflux transporters, LRP-1 and P-gp, no change in RAGE expression and a decrease in LRP-2, the CP epithelium influx transporter, at the BCSFB with aging. Decreased Aβ42 concentration in the CP, as measured by quantitative IHC, was associated with these Aβ transporter alterations. Conclusions Age-dependent alterations in the CP Aβ transporters are associated with a decrease in Aβ42 accumulation in the CP, and are reciprocal to the changes seen in these transporters at the BBB, suggesting a possible compensatory role for the BCSFB in Aβ clearance in aging.
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Affiliation(s)
- Crissey L Pascale
- Warren Alpert Medical School Brown University, RI Hospital Department of Neurosurgery 593 Eddy St, Providence, RI 02903 USA.
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243
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Wang J, Zhu C, Xu Y, Liu B, Wang M, Wu K. Development and expression of amyloid-β peptide 42 in retinal ganglion cells in rats. Anat Rec (Hoboken) 2011; 294:1401-5. [PMID: 21717587 DOI: 10.1002/ar.21438] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2010] [Accepted: 04/20/2011] [Indexed: 11/10/2022]
Abstract
The previous studies have shown that amyloid-β peptide (Aβ) was mainly found in neurons of neurodegenerative diseases, such as Alzheimer's disease (AD) and glaucoma and little is known about its expression in normal nerve cells. The aim of the present study was to investigate the expression of amyloid-β peptide 42 (Aβ-42) in retinal ganglion cells of the postnatal rats. Rats were divided into seven experimental groups: 3, 6, 13, 15, 25, 60, and 90 days postnatal groups. Rats from 15 and 25 days postnatal groups were further divided into light-exposure and non light-exposure group. Cryosections or flat-mounted retinas of rat eyes were used for testing Aβ-42 by immunocytochemistry staining. Aβ-42 expression was not observed in rats within 13 days after birth, but was easily detectable in all groups of rats over 15 days after birth. In addition, the expression of Aβ-42 in retina was increasing as the rats got older, reached to highest level in 60 days after birth. Furthermore, the expression of Aβ-42 was not detected in rats kept under dark indicating that light is required for the expression of Aβ-42 in retina. This is the first report showing that normal retinal ganglion cells express Aβ-42, and that the expression of Aβ-42 in retinal ganglion cells requires the exposure to light. These data suggest that Aβ-42 may play a important role in vision development.
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244
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Park SH, Kim JH, Bae SS, Hong KW, Choi BT, Shin HK. Phosphodiesterase III Inhibitor Cilostazol Protects Amyloid β-Induced Neuronal Cell Injury via Peroxisome Proliferator-Activated Receptor-γ Activation. ACTA ACUST UNITED AC 2011. [DOI: 10.5352/jls.2011.21.5.647] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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245
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Grasso G. The use of mass spectrometry to study amyloid-β peptides. MASS SPECTROMETRY REVIEWS 2011; 30:347-365. [PMID: 21500241 DOI: 10.1002/mas.20281] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2009] [Revised: 11/06/2009] [Accepted: 11/06/2009] [Indexed: 05/30/2023]
Abstract
Amyloid-β peptide (Aβ) varies in size from 39 to 43 amino acids and arises from sequential β- and γ-secretase processing of the amyloid precursor protein. Whereas the non-pathological role for Aβ is yet to be established, there is no disputing that Aβ is now widely regarded as central to the development of Alzheimer's disease (AD). The so named "amyloid cascade hypothesis" states that disease progression is the result of an increased Aβ burden in affected areas of the brain. To elucidate the Aβ role in AD, many analytical approaches have been proposed as suitable tools to investigate not only the total Aβ load but also many other issues that are considered crucial for AD, such as: (i) the aggregation state in which Aβ is present; (ii) its interaction with other species or metals; (iii) its ability to induce oxidative stress; and (iv) its degradative pathways. This review provides an insight into the use of mass spectrometry (MS) in the field of Aβ investigation aimed to assess its role in AD. In particular, the different MS-based approaches applied in vitro and in vivo that can provide detailed information on the above-mentioned issues are reviewed. Moreover, the advantages offered by the MS methods over all the other techniques are highlighted, together with the recent developments and uses of combined analytical approaches to detect and characterize Aβ.
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Affiliation(s)
- Giuseppe Grasso
- Chemistry Department, Università di Catania, Viale Andrea Doria 6, Catania 95125, Italy.
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246
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Zhang Y, Lee DHS. Sink Hypothesis and Therapeutic Strategies for Attenuating Aβ Levels. Neuroscientist 2011; 17:163-173. [DOI: 10.1177/1073858410381532] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/30/2023]
Abstract
Amyloid β (Aβ) plaque, comprised mainly by Aβ peptides, is an important pathology of Alzheimer’s brains. Major efforts have been devoted to targeting this neurotoxic Aβ peptide for discovering disease-modifying treatments for Alzheimer’s disease. Inasmuch as Aβ is found in both the brain and the periphery, it is hypothesized that there is some form of equilibrium for the Aβ in the brain and the periphery such that Aβ can be transported across the blood-brain barrier. By modulating the periphery Aβ levels, it is predicted that the brain Aβ levels will undergo concomitant changes, forming the basis of the “sink hypothesis” for Aβ lowering strategies. In this review, the significance and implication of this sink hypothesis as well as how the sink hypothesis may contribute to the recent Aβ-based drug discovery in AD are discussed. Ultimately, the validity of the sink hypothesis will be resolved when the appropriate Aβ agents are being tested in the clinic.
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Affiliation(s)
- Yan Zhang
- Laboratory of Neurobiology and State Key Laboratory of Biomembrane and Membrane Biotechnology, College of Life Sciences, Peking University, Beijing, 100871, China,
| | - Daniel H. S. Lee
- Translational Medicine, GlaxoSmithKline R&D, Shanghai, 20001, China
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247
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Biochemical studies in Normal Pressure Hydrocephalus (NPH) patients: change in CSF levels of amyloid precursor protein (APP), amyloid-beta (Aβ) peptide and phospho-tau. J Psychiatr Res 2011; 45:539-47. [PMID: 20828718 PMCID: PMC3813465 DOI: 10.1016/j.jpsychires.2010.07.011] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2010] [Revised: 07/13/2010] [Accepted: 07/27/2010] [Indexed: 11/22/2022]
Abstract
Normal Pressure Hydrocephalus (NPH) is one of the causes of dementia of the elderly characterized by impaired mental function, gait difficulties and urinary incontinence. Previously, it was proposed that some of the NPH patients may develop Alzheimer's disease (AD) like pathology. Aim of this study was to compare levels of different CSF biomarkers, including total secreted β-amyloid precursor protein (sAPP), sAPP-alpha form (sAPPα), amyloid-beta (Aβ) peptide, total-tau protein and hyperphosphorylated-tau protein in subjects from NPH and Non-NPH Control (NNC). CSF was collected from 23 NPH patients and 13 Non-NPH controls by lumber puncture. Western blot analysis was performed to measure levels of sAPP-total. ELISA was used separately to determine levels of sAPPα, Aβ peptide, total-tau and phospho-tau proteins. We found a significant decrease in levels of total secreted APP, sAPPα and Aβ (1-42) in the CSF sample of NPH patients vs. NNC. We did not observe any change in levels of total-tau or phospho-tau in NPH vs. NNC subjects. Notably, phospho-tau level was significantly increased in the NPH patients, who were suffering from the disease for more than one year, vs. NNC. Among five biomarkers studied, decreased sAPP, sAPPα and Aβ (1-42) levels in CSF can be molecular markers to distinguish NPH cases from NNC. Disease severity can also be assessed by increased levels of CSF phospho-tau protein and the ratio of phospho-tau to Aβ (1-42), which might be a useful tool for predicting conversion of NPH individuals to other neurodegenerative disorders including Alzheimer's disease (AD).
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248
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Ortega A, Rincón Á, Jiménez-Aliaga KL, Bermejo-Bescós P, Martín-Aragón S, Molina MT, Csákÿ AG. Synthesis and evaluation of arylquinones as BACE1 inhibitors, β-amyloid peptide aggregation inhibitors, and destabilizers of preformed β-amyloid fibrils. Bioorg Med Chem Lett 2011; 21:2183-7. [PMID: 21441028 DOI: 10.1016/j.bmcl.2011.03.023] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2011] [Revised: 03/05/2011] [Accepted: 03/08/2011] [Indexed: 01/04/2023]
Abstract
BACE1 activity, inhibition of Aβ aggregation, and disaggregation of preformed Aβ fibrils constitute the three major targets in the development of small-molecule lipophilic new drugs for the treatment of Alzheimer's disease (AD). Quinones are widely distributed among natural products and possess relevant and varied biological activities including antitumor and antibiotic, inhibition of HIV-1 reverse transcriptase, antidiabetic, or COX-inhibition, among others. We report herein the interaction of several arylquinones and their derivatives with the amyloidogenic pathway of the amyloid precursor protein processing. Our studies put forward that these compounds are promising candidates in the development of new drugs which are effective simultaneously towards the three major targets of AD.
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Affiliation(s)
- Andrea Ortega
- Departamento de Farmacología, Facultad de Farmacia, Universidad Complutense, E28040 Madrid, Spain
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249
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Tian Y, Bustos V, Flajolet M, Greengard P. A small-molecule enhancer of autophagy decreases levels of Abeta and APP-CTF via Atg5-dependent autophagy pathway. FASEB J 2011; 25:1934-42. [PMID: 21368103 DOI: 10.1096/fj.10-175158] [Citation(s) in RCA: 165] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The hallmarks of Alzheimer's disease are the aggregates of amyloid-β (Αβ) peptide and tau protein. Autophagy is one major cellular pathway leading to the removal of aggregated proteins. We examined the possibility of inducing autophagy to reduce Aβ peptide and the amyloid precursor protein (APP)-derived fragment APP-CTF levels in cell lines and primary neuronal cultures. We found that induction of autophagy either by small-molecule enhancers of rapamycin (SMER)28, a small-molecule enhancer of autophagy, or following starvation greatly decreased the levels of Aβ peptide (apparent EC(50) of ∼10 μM) and APP-CTF (apparent EC(50) of ∼20 μM) in a γ-secretase-independent manner. Pharmacological inhibition of autophagy led to a significant accumulation of Aβ peptide and APP-CTF and diminished the effect of SMER28. Three essential components of the autophagic pathway, autophagy-related protein (Atg)5, Beclin1, and Ulk1, were shown to be involved in the degradation of Aβ and APP-CTF, and Atg5 was necessary for the effect of SMER28. In addition, the autophagic marker light chain 3-II cocompartmentalized with APP-CTF. These results support the involvement of autophagy in the clearance of Aβ and APP-CTF. We therefore propose that small molecule enhancers of autophagy, such as SMER28, may have therapeutic potential for the treatment of Alzheimer's disease and other proteinopathies.
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Affiliation(s)
- Yuan Tian
- Laboratory of Molecular and Cellular Neuroscience, Rockefeller University, 1230 York Ave., New York, NY 10065, USA
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250
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Leung E, Guo L, Bu J, Maloof M, Khoury JE, Geula C. Microglia activation mediates fibrillar amyloid-β toxicity in the aged primate cortex. Neurobiol Aging 2011; 32:387-97. [PMID: 19349094 PMCID: PMC2888944 DOI: 10.1016/j.neurobiolaging.2009.02.025] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2008] [Revised: 02/20/2009] [Accepted: 02/25/2009] [Indexed: 11/18/2022]
Abstract
The amyloid-β peptide (Aβ) plays a central role in the pathogenesis of Alzheimer's disease (AD). The fibrillar form of Aβ (fAβ) exerts toxic effects on neurons through mechanisms not well understood. We have shown that the aged primate cortex is selectively vulnerable to fAβ toxicity at low concentrations. In addition to neuronal loss, fAβ induced massive activation of microglia in the aged rhesus cortex. We now demonstrate that inhibition of microglia activation abolishes fAβ toxicity. Injection or pump delivery of macrophage/microglia inhibitory factor (MIF) significantly reduced activation of microglia and the volume of damage caused by fAβ. Microglia isolated from aged rhesus cortex produced substantial reactive oxygen species when stimulated by fAβ, which was inhibited by MIF in a dose-dependent manner. This is the first definitive in vivo demonstration that the fAβ-induced microglia activation and inflammation mediate, at least in part, its toxic effects on neurons. Combined with our earlier observations, these findings suggest that aged primate microglia may display an exaggerated inflammatory response to fAβ when compared with young microglia.
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Affiliation(s)
- Elaine Leung
- Laboratory for Cognitive and Molecular Morphometry, Cognitive Neurology and Alzheimer's Disease Center, Northwestern University, Feinberg School of Medicine, Chicago, IL, United States
- Department of Medicine, Harvard Medical School and Division of Gerontology, Beth Israel Deaconess Medical Center, Boston, MA, United States
| | - Ling Guo
- Laboratory for Cognitive and Molecular Morphometry, Cognitive Neurology and Alzheimer's Disease Center, Northwestern University, Feinberg School of Medicine, Chicago, IL, United States
| | - Jing Bu
- Laboratory for Cognitive and Molecular Morphometry, Cognitive Neurology and Alzheimer's Disease Center, Northwestern University, Feinberg School of Medicine, Chicago, IL, United States
- Department of Medicine, Harvard Medical School and Division of Gerontology, Beth Israel Deaconess Medical Center, Boston, MA, United States
| | - Marie Maloof
- Laboratory for Cognitive and Molecular Morphometry, Cognitive Neurology and Alzheimer's Disease Center, Northwestern University, Feinberg School of Medicine, Chicago, IL, United States
- Department of Medicine, Harvard Medical School and Division of Gerontology, Beth Israel Deaconess Medical Center, Boston, MA, United States
| | - Joseph El Khoury
- Department of Medicine, Harvard Medical School and Division of Infectious Disease, Center for Immunology and Inflammatory Diseases, Massachusetts General Hospital, Boston, MA, United States
| | - Changiz Geula
- Laboratory for Cognitive and Molecular Morphometry, Cognitive Neurology and Alzheimer's Disease Center, Northwestern University, Feinberg School of Medicine, Chicago, IL, United States
- Department of Medicine, Harvard Medical School and Division of Gerontology, Beth Israel Deaconess Medical Center, Boston, MA, United States
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