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Albert-Gascó H, Ros-Bernal F, Castillo-Gómez E, Olucha-Bordonau FE. MAP/ERK Signaling in Developing Cognitive and Emotional Function and Its Effect on Pathological and Neurodegenerative Processes. Int J Mol Sci 2020; 21:E4471. [PMID: 32586047 PMCID: PMC7352860 DOI: 10.3390/ijms21124471] [Citation(s) in RCA: 88] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Revised: 06/14/2020] [Accepted: 06/17/2020] [Indexed: 12/13/2022] Open
Abstract
The signaling pathway of the microtubule-associated protein kinase or extracellular regulated kinase (MAPK/ERK) is a common mechanism of extracellular information transduction from extracellular stimuli to the intracellular space. The transduction of information leads to changes in the ongoing metabolic pathways and the modification of gene expression patterns. In the central nervous system, ERK is expressed ubiquitously, both temporally and spatially. As for the temporal ubiquity, this signaling system participates in three key moments: (i) Embryonic development; (ii) the early postnatal period; and iii) adulthood. During embryonic development, the system is partly responsible for the patterning of segmentation in the encephalic vesicle through the FGF8-ERK pathway. In addition, during this period, ERK directs neurogenesis migration and the final fate of neural progenitors. During the early postnatal period, ERK participates in the maturation process of dendritic trees and synaptogenesis. During adulthood, ERK participates in social and emotional behavior and memory processes, including long-term potentiation. Alterations in mechanisms related to ERK are associated with different pathological outcomes. Genetic alterations in any component of the ERK pathway result in pathologies associated with neural crest derivatives and mental dysfunctions associated with autism spectrum disorders. The MAP-ERK pathway is a key element of the neuroinflammatory pathway triggered by glial cells during the development of neurodegenerative diseases, such as Parkinson's and Alzheimer's disease, Huntington's disease, and amyotrophic lateral sclerosis, as well as prionic diseases. The process triggered by MAPK/ERK activation depends on the stage of development (mature or senescence), the type of cellular element in which the pathway is activated, and the anatomic neural structure. However, extensive gaps exist with regards to the targets of the phosphorylated ERK in many of these processes.
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Affiliation(s)
- Héctor Albert-Gascó
- UK Dementia Research Institute, Department of Clinical Neurosciences, University of Cambridge, Hills Road, Cambridge CB2 0AH, UK;
| | - Francisco Ros-Bernal
- U.P Medicina, Facultad de Ciencias de la Salud, Universitat Jaume I, Avda. de Vicent Sos Baynat s/n, 12071 Castelló de la Plana, Spain; (F.R.-B.); (E.C.-G.)
| | - Esther Castillo-Gómez
- U.P Medicina, Facultad de Ciencias de la Salud, Universitat Jaume I, Avda. de Vicent Sos Baynat s/n, 12071 Castelló de la Plana, Spain; (F.R.-B.); (E.C.-G.)
- Spanish National Network for Research in Mental Health, Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Planta 0, 28029 Madrid, Spain
| | - Francisco E. Olucha-Bordonau
- U.P Medicina, Facultad de Ciencias de la Salud, Universitat Jaume I, Avda. de Vicent Sos Baynat s/n, 12071 Castelló de la Plana, Spain; (F.R.-B.); (E.C.-G.)
- Spanish National Network for Research in Mental Health, Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Planta 0, 28029 Madrid, Spain
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Catorce MN, Gevorkian G. LPS-induced Murine Neuroinflammation Model: Main Features and Suitability for Pre-clinical Assessment of Nutraceuticals. Curr Neuropharmacol 2016; 14:155-64. [PMID: 26639457 PMCID: PMC4825946 DOI: 10.2174/1570159x14666151204122017] [Citation(s) in RCA: 238] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Revised: 11/02/2015] [Accepted: 12/04/2015] [Indexed: 12/14/2022] Open
Abstract
Neuroinflammation is an important feature in the pathogenesis and progression of neurodegenerative diseases such as Alzheimer´s disease (AD), Parkinson´s disease (PD), frontotemporal dementia and amyotrophic lateral sclerosis. Based on current knowledge in the field, suggesting that targeting peripheral inflammation could be a promising additional treatment/prevention approach for neurodegenerative diseases, drugs and natural products with anti-inflammatory properties have been evaluated in animal models of neuroinflammation and neurodegeneration. In this review, we provide an extensive analysis of one of the most important and widely-used animal models of peripherally induced neuroinflammation and neurodegeneration - lipopolysaccharide (LPS)-treated mice, and address the data reproducibility in published research. We also summarize briefly basic features of various natural products, nutraceuticals, with known anti-inflammatory effects and present an overview of data on their therapeutic potential for reducing neuroinflammation in LPS-treated mice.
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Affiliation(s)
| | - Goar Gevorkian
- Instituto de Investigaciones Biomedicas, Universidad Nacional Autonoma de Mexico (UNAM), Apartado Postal 70228, Cuidad Universitaria, Mexico DF, CP 04510, Mexico.
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Hook G, Yu J, Toneff T, Kindy M, Hook V. Brain pyroglutamate amyloid-β is produced by cathepsin B and is reduced by the cysteine protease inhibitor E64d, representing a potential Alzheimer's disease therapeutic. J Alzheimers Dis 2015; 41:129-49. [PMID: 24595198 DOI: 10.3233/jad-131370] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Pyroglutamate amyloid-β peptides (pGlu-Aβ) are particularly pernicious forms of amyloid-β peptides (Aβ) present in Alzheimer's disease (AD) brains. pGlu-Aβ peptides are N-terminally truncated forms of full-length Aβ peptides (flAβ(1-40/42)) in which the N-terminal glutamate is cyclized to pyroglutamate to generate pGlu-Aβ(3-40/42). β-secretase cleavage of amyloid-β precursor protein (AβPP) produces flAβ(1-40/42), but it is not yet known whether the β-secretase BACE1 or the alternative β-secretase cathepsin B (CatB) participate in the production of pGlu-Aβ. Therefore, this study examined the effects of gene knockout of these proteases on brain pGlu-Aβ levels in transgenic AβPPLon mice, which express AβPP isoform 695 and have the wild-type (wt) β-secretase activity found in most AD patients. Knockout or overexpression of the CatB gene reduced or increased, respectively, pGlu-Aβ(3-40/42), flAβ(1-40/42), and pGlu-Aβ plaque load, but knockout of the BACE1 gene had no effect on those parameters in the transgenic mice. Treatment of AβPPLon mice with E64d, a cysteine protease inhibitor of CatB, also reduced brain pGlu-Aβ(3-42), flAβ(1-40/42), and pGlu-Aβ plaque load. Treatment of neuronal-like chromaffin cells with CA074Me, an inhibitor of CatB, resulted in reduced levels of pGlu-Aβ(3-40) released from the activity-dependent, regulated secretory pathway. Moreover, CatB knockout and E64d treatment has been previously shown to improve memory deficits in the AβPPLon mice. These data illustrate the role of CatB in producing pGlu-Aβ and flAβ that participate as key factors in the development of AD. The advantages of CatB inhibitors, especially E64d and its derivatives, as alternatives to BACE1 inhibitors in treating AD patients are discussed.
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Affiliation(s)
- Gregory Hook
- American Life Science Pharmaceuticals, La Jolla, CA, USA
| | - Jin Yu
- Department of Neurosciences, Medical University of South Carolina, Charleston, SC, USA Ralph H. Johnson VA Medical Center, Charleston, SC, USA
| | - Thomas Toneff
- Skaggs School of Pharmacy and Pharmaceutical Sciences, Departments of Neurosciences and Pharmacology, University of California, San Diego, La Jolla, CA, USA
| | - Mark Kindy
- Department of Neurosciences, Medical University of South Carolina, Charleston, SC, USA Ralph H. Johnson VA Medical Center, Charleston, SC, USA
| | - Vivian Hook
- Skaggs School of Pharmacy and Pharmaceutical Sciences, Departments of Neurosciences and Pharmacology, University of California, San Diego, La Jolla, CA, USA
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Kindy MS, Yu J, Zhu H, El-Amouri SS, Hook V, Hook GR. Deletion of the cathepsin B gene improves memory deficits in a transgenic ALZHeimer's disease mouse model expressing AβPP containing the wild-type β-secretase site sequence. J Alzheimers Dis 2012; 29:827-40. [PMID: 22337825 DOI: 10.3233/jad-2012-111604] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Therapeutic agents that improve the memory loss of Alzheimer's disease (AD) may eventually be developed if drug targets are identified that improve memory deficits in appropriate AD animal models. One such target is β-secretase which, in most AD patients, cleaves the wild-type (WT) β-secretase site sequence of the amyloid-β protein precursor (AβPP) to produce neurotoxic amyloid-β (Aβ). Thus, an animal model representing most AD patients for evaluating β-secretase effects on memory deficits is one that expresses human AβPP containing the WT β-secretase site sequence. BACE1 and cathepsin B (CatB) proteases have β-secretase activity, but gene knockout studies have not yet validated that the absence of these proteases improves memory deficits in such an animal model. This study assessed the effects of deleting these protease genes on memory deficits in the AD mouse model expressing human AβPP containing the WT β-secretase site sequence and the London γ-secretase site (AβPPWT/Lon mice). Knockout of the CatB gene in the AβPPWT/Lon mice improved memory deficits and altered the pattern of Aβ-related biomarkers in a manner consistent with CatB having WT β-secretase activity. But deletion of the BACE1 gene had no effect on these parameters in the AβPPWT/Lon mice. These data are the first to show that knockout of a putative β-secretase gene results in improved memory in an AD animal model expressing the WT β-secretase site sequence of AβPP, present in the majority of AD patients. CatB may be an effective drug target for improving memory deficits in most AD patients.
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Affiliation(s)
- Mark S Kindy
- Department of Neurosciences, Medical University of South Carolina, Charleston, SC 29425, USA.
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Masliah E, Rockenstein E, Inglis C, Adame A, Bett C, Lucero M, Sigurdson CJ. Prion infection promotes extensive accumulation of α-synuclein in aged human α-synuclein transgenic mice. Prion 2012; 6:184-90. [PMID: 22460692 DOI: 10.4161/pri.19806] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
In neurodegenerative disorders of the aging population, misfolded proteins, such as PrP(Sc), α-synuclein, amyloid β protein and tau, can interact resulting in enhanced aggregation, cross seeding and accelerated disease progression. Previous reports have shown that in Creutzfeldt-Jakob disease and scrapie, α-synuclein accumulates near PrP(Sc) deposits. However, it is unclear if pre-existing human α-synuclein aggregates modified prion disease pathogenesis, or if PrP(Sc) exacerbates the α-synuclein pathology. Here, we inoculated infectious prions into aged α-synuclein transgenic (tg) and non-transgenic littermate control mice by the intracerebral route. Remarkably, inoculation of RML and mNS prions into α-synuclein tg mice resulted in more extensive and abundant intraneuronal and synaptic α-synuclein accumulation. In addition, infectious prions led to the formation of perineuronal α-synuclein deposits with a neuritic plaque-like appearance. Prion pathology was unmodified by the presence of α-synuclein. However, with the mNS prion strain there was a modest but significant acceleration in the time to terminal prion disease in mice having α-synuclein aggregates as compared with non-tg mice. Taken together, these studies support the notion that PrP(Sc) directly or indirectly promotes α-synuclein pathology.
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Affiliation(s)
- Eliezer Masliah
- Department of Neuroscience, University of California, San Diego, La Jolla, CA, USA.
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Hook V, Funkelstein L, Wegrzyn J, Bark S, Kindy M, Hook G. Cysteine Cathepsins in the secretory vesicle produce active peptides: Cathepsin L generates peptide neurotransmitters and cathepsin B produces beta-amyloid of Alzheimer's disease. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2011; 1824:89-104. [PMID: 21925292 DOI: 10.1016/j.bbapap.2011.08.015] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2011] [Revised: 08/26/2011] [Accepted: 08/29/2011] [Indexed: 12/01/2022]
Abstract
Recent new findings indicate significant biological roles of cysteine cathepsin proteases in secretory vesicles for production of biologically active peptides. Notably, cathepsin L in secretory vesicles functions as a key protease for proteolytic processing of proneuropeptides (and prohormones) into active neuropeptides that are released to mediate cell-cell communication in the nervous system for neurotransmission. Moreover, cathepsin B in secretory vesicles has been recently identified as a β-secretase for production of neurotoxic β- amyloid (Aβ) peptides that accumulate in Alzheimer's disease (AD), participating as a notable factor in the severe memory loss in AD. These secretory vesicle functions of cathepsins L and B for production of biologically active peptides contrast with the well-known role of cathepsin proteases in lysosomes for the degradation of proteins to result in their inactivation. The unique secretory vesicle proteome indicates proteins of distinct functional categories that provide the intravesicular environment for support of cysteine cathepsin functions. Features of the secretory vesicle protein systems insure optimized intravesicular conditions that support the proteolytic activity of cathepsins. These new findings of recently discovered biological roles of cathepsins L and B indicate their significance in human health and disease. This article is part of a Special Issue entitled: Proteolysis 50 years after the discovery of lysosome.
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Affiliation(s)
- Vivian Hook
- Skaggs School of Pharmacy and Pharmaceutical Sciences, Dept. of Neurosciences, Univ. of Calif., San Diego, USA.
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Hook V, Hook G, Kindy M. Pharmacogenetic features of cathepsin B inhibitors that improve memory deficit and reduce beta-amyloid related to Alzheimer's disease. Biol Chem 2010; 391:861-72. [PMID: 20536395 PMCID: PMC4309269 DOI: 10.1515/bc.2010.110] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Beta-amyloid (Abeta) in the brain is a major factor involved in Alzheimer's disease (AD) that results in severe memory deficit. Our recent studies demonstrate pharmacogenetic differences in the effects of inhibitors of cathepsin B to improve memory and reduce Abeta in different mouse models of AD. The inhibitors improve memory and reduce brain Abeta in mice expressing the wild-type (WT) beta-secretase site of human APP, expressed in most AD patients. However, these inhibitors have no effect in mice expressing the rare Swedish (Swe) mutant amyloid precursor protein (APP). Knockout of the cathepsin B decreased brain Abeta in mice expressing WT APP, validating cathepsin B as the target. The specificity of cathepsin B to cleave the WT beta-secretase site, but not the Swe mutant site, of APP for Abeta production explains the distinct inhibitor responses in the different AD mouse models. In contrast to cathepsin B, the BACE1 beta-secretase prefers to cleave the Swe mutant site. Discussion of BACE1 data in the field indicate that they do not preclude cathepsin B as also being a beta-secretase. Cathepsin B and BACE1 could participate jointly as beta-secretases. Significantly, the majority of AD patients express WT APP and, therefore, inhibitors of cathepsin B represent candidate drugs for AD.
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Affiliation(s)
- Vivian Hook
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA 92093, USA.
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Paleologou KE, Oueslati A, Shakked G, Rospigliosi CC, Kim HY, Lamberto GR, Fernandez CO, Schmid A, Chegini F, Gai WP, Chiappe D, Moniatte M, Schneider BL, Aebischer P, Eliezer D, Zweckstetter M, Masliah E, Lashuel HA. Phosphorylation at S87 is enhanced in synucleinopathies, inhibits alpha-synuclein oligomerization, and influences synuclein-membrane interactions. J Neurosci 2010; 30:3184-98. [PMID: 20203178 PMCID: PMC2947449 DOI: 10.1523/jneurosci.5922-09.2010] [Citation(s) in RCA: 234] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2009] [Accepted: 12/26/2009] [Indexed: 12/19/2022] Open
Abstract
Increasing evidence suggests that phosphorylation may play an important role in the oligomerization, fibrillogenesis, Lewy body (LB) formation, and neurotoxicity of alpha-synuclein (alpha-syn) in Parkinson disease. Herein we demonstrate that alpha-syn is phosphorylated at S87 in vivo and within LBs. The levels of S87-P are increased in brains of transgenic (TG) models of synucleinopathies and human brains from Alzheimer disease (AD), LB disease (LBD), and multiple system atrophy (MSA) patients. Using antibodies against phosphorylated alpha-syn (S129-P and S87-P), a significant amount of immunoreactivity was detected in the membrane in the LBD, MSA, and AD cases but not in normal controls. In brain homogenates from diseased human brains and TG animals, the majority of S87-P alpha-syn was detected in the membrane fractions. A battery of biophysical methods were used to dissect the effect of S87 phosphorylation on the structure, aggregation, and membrane-binding properties of monomeric alpha-syn. These studies demonstrated that phosphorylation at S87 expands the structure of alpha-syn, increases its conformational flexibility, and blocks its fibrillization in vitro. Furthermore, phosphorylation at S87, but not S129, results in significant reduction of alpha-syn binding to membranes. Together, our findings provide novel mechanistic insight into the role of phosphorylation at S87 and S129 in the pathogenesis of synucleinopathies and potential roles of phosphorylation in alpha-syn normal biology.
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Affiliation(s)
| | - Abid Oueslati
- Laboratory of Molecular Neurobiology and Neuroproteomics, Brain Mind Institute
| | - Gideon Shakked
- Department of Neurosciences, University of California, San Diego, La Jolla, California 92093
| | - Carla C. Rospigliosi
- Department of Biochemistry and Program in Structural Biology, Weill Cornell Medical College, New York, New York 10021
| | - Hai-Young Kim
- Department of NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
| | - Gonzalo R. Lamberto
- Instituto de Biología Molecular y Celular de Rosario, Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad Nacional de Rosario, Suipacha 531, S2002LRK, Rosario, Argentina
| | - Claudio O. Fernandez
- Instituto de Biología Molecular y Celular de Rosario, Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad Nacional de Rosario, Suipacha 531, S2002LRK, Rosario, Argentina
| | - Adrian Schmid
- Laboratory of Molecular Neurobiology and Neuroproteomics, Brain Mind Institute
| | - Fariba Chegini
- Department of Human Physiology, Flinders University School of Medicine, Bedford Park, South Australia 5042, Australia, and
| | - Wei Ping Gai
- Department of Human Physiology, Flinders University School of Medicine, Bedford Park, South Australia 5042, Australia, and
| | - Diego Chiappe
- The Ecole Polytechnique Fédérale de Lausanne (EPFL) Proteomic Core Facility, School of Life Sciences, and
| | - Marc Moniatte
- The Ecole Polytechnique Fédérale de Lausanne (EPFL) Proteomic Core Facility, School of Life Sciences, and
| | | | | | - David Eliezer
- Department of Biochemistry and Program in Structural Biology, Weill Cornell Medical College, New York, New York 10021
| | - Markus Zweckstetter
- Department of NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
- Deutsche Forschungsgemeinschaft (DFG) Research Center for the Molecular Physiology of the Brain (CMPB), 37073 Göttingen, Germany
| | - Eliezer Masliah
- Department of Neurosciences, University of California, San Diego, La Jolla, California 92093
| | - Hilal A. Lashuel
- Laboratory of Molecular Neurobiology and Neuroproteomics, Brain Mind Institute
- The Ecole Polytechnique Fédérale de Lausanne (EPFL) Proteomic Core Facility, School of Life Sciences, and
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Cohen E, Paulsson JF, Blinder P, Burstyn-Cohen T, Du D, Estepa G, Adame A, Pham HM, Holzenberger M, Kelly JW, Masliah E, Dillin A. Reduced IGF-1 signaling delays age-associated proteotoxicity in mice. Cell 2009; 139:1157-69. [PMID: 20005808 PMCID: PMC3017511 DOI: 10.1016/j.cell.2009.11.014] [Citation(s) in RCA: 372] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2009] [Revised: 09/11/2009] [Accepted: 10/29/2009] [Indexed: 12/28/2022]
Abstract
The insulin/insulin growth factor (IGF) signaling (IIS) pathway is a key regulator of aging of worms, flies, mice, and likely humans. Delayed aging by IIS reduction protects the nematode C. elegans from toxicity associated with the aggregation of the Alzheimer's disease-linked human peptide, Abeta. We reduced IGF signaling in Alzheimer's model mice and discovered that these animals are protected from Alzheimer's-like disease symptoms, including reduced behavioral impairment, neuroinflammation, and neuronal loss. This protection is correlated with the hyperaggregation of Abeta leading to tightly packed, ordered plaques, suggesting that one aspect of the protection conferred by reduced IGF signaling is the sequestration of soluble Abeta oligomers into dense aggregates of lower toxicity. These findings indicate that the IGF signaling-regulated mechanism that protects from Abeta toxicity is conserved from worms to mammals and point to the modulation of this signaling pathway as a promising strategy for the development of Alzheimer's disease therapy.
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Affiliation(s)
- Ehud Cohen
- Howard Hughes Medical Institute, Glenn Center for Aging Research, Molecular and Cell Biology Laboratory, The Salk Institute for Biological Studies, 10010 N. Torrey Pines Road, La Jolla, CA 92037, USA
| | - Johan F. Paulsson
- Department of Chemistry and Molecular and Experimental Medicine and The Skaggs Institute of Chemical Biology, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, CA 92037, USA
| | - Pablo Blinder
- Department of Physics, University of California San Diego
| | - Tal Burstyn-Cohen
- Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, 10010 N. Torrey Pines Road, La Jolla, CA 92037, USA
| | - Deguo Du
- Department of Chemistry and Molecular and Experimental Medicine and The Skaggs Institute of Chemical Biology, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, CA 92037, USA
| | - Gabriela Estepa
- Howard Hughes Medical Institute, Glenn Center for Aging Research, Molecular and Cell Biology Laboratory, The Salk Institute for Biological Studies, 10010 N. Torrey Pines Road, La Jolla, CA 92037, USA
| | - Anthony Adame
- Department of Neurosciences, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Hang M. Pham
- Department of Neurosciences, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | | | - Jeffery W. Kelly
- Department of Chemistry and Molecular and Experimental Medicine and The Skaggs Institute of Chemical Biology, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, CA 92037, USA
| | - Eliezer Masliah
- Department of Neurosciences, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Andrew Dillin
- Howard Hughes Medical Institute, Glenn Center for Aging Research, Molecular and Cell Biology Laboratory, The Salk Institute for Biological Studies, 10010 N. Torrey Pines Road, La Jolla, CA 92037, USA
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Hook V, Schechter I, Demuth HU, Hook G. Alternative pathways for production of beta-amyloid peptides of Alzheimer's disease. Biol Chem 2008; 389:993-1006. [PMID: 18979625 DOI: 10.1515/bc.2008.124] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
This highlight article describes three Alzheimer's disease (AD) studies presented at the 5th General Meeting of the International Proteolysis Society that address enzymatic mechanisms for producing neurotoxic beta-amyloid (Abeta) peptides. One group described the poor kinetics of BACE 1 for cleaving the wild-type (WT) beta-secretase site of APP found in most AD patients. They showed that cathepsin D displays BACE 1-like specificity and cathepsin D is 280-fold more abundant in human brain than BACE 1. Nevertheless, as BACE 1 and cathepsin D show poor activity towards the WT beta-secretase site, they suggested continuing the search for additional beta-secretase(s). The second group reported cathepsin B as an alternative beta-secretase possessing excellent kinetic efficiency and specificity for the WT beta-secretase site. Significantly, inhibitors of cathepsin B improved memory, with reduced amyloid plaques and decreased Abeta(40/42) in brains of AD animal models expressing amyloid precursor protein containing the WT beta-secretase site. The third group addressed isoaspartate and pyroglutamate (pGlu) posttranslational modifications of Abeta. Results showed that cathepsin B, but not BACE 1, efficiently cleaves the WT beta-secretase isoaspartate site. Furthermore, cyclization of N-terminal Glu by glutaminyl cyclase generates highly amyloidogenic pGluAbeta(3-40/42). These presentations suggest cathepsin B and glutaminyl cyclase as potential new AD therapeutic targets.
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Affiliation(s)
- Vivian Hook
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California at San Diego, La Jolla, CA 92093, USA.
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11
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Nguyen TVV, Galvan V, Huang W, Banwait S, Tang H, Zhang J, Bredesen DE. Signal transduction in Alzheimer disease: p21-activated kinase signaling requires C-terminal cleavage of APP at Asp664. J Neurochem 2007; 104:1065-80. [PMID: 17986220 DOI: 10.1111/j.1471-4159.2007.05031.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The deficits in Alzheimer disease (AD) stem at least partly from neurotoxic beta-amyloid peptides generated from the amyloid precursor protein (APP). APP may also be cleaved intracellularly at Asp664 to yield a second neurotoxic peptide, C31. Previously, we showed that cleavage of APP at the C-terminus is required for the impairments seen in APP transgenic mice, by comparing elements of the disease in animals modeling AD, with (platelet-derived growth factor B-chain promoter-driven APP transgenic mice; PDAPP) versus without (PDAPP D664A) a functional Asp664 caspase cleavage site. However, the signaling mechanism(s) by which Asp664 contributes to these deficits remains to be elucidated. In this study, we identify a kinase protein, recently shown to bind APP at the C-terminus and to contribute to AD, whose activity is modified in PDAPP mice, but normalized in PDAPP D664A mice. Specifically, we observed a significant increase in nuclear p21-activated kinase (isoforms 1, 2, and or 3; PAK-1/2/3) activation in hippocampus of 3 month old PDAPP mice compared with non-transgenic littermates, an effect completely prevented in PDAPP D664A mice. In contrast, 13 month old PDAPP mice displayed a significant decrease in PAK-1/2/3 activity, which was once again absent in PDAPP D664A mice. Similarly, in hippocampus of early and severe AD subjects, there was a progressive and subcellular-specific reduction in active PAK-1/2/3 compared with normal controls. Interestingly, total PAK-1/2/3 protein was increased in early AD subjects, but declined in moderate AD and declined further, to significantly below that of control levels, in severe AD. These findings are compatible with previous suggestions that PAK may be involved in the pathophysiology of AD, and demonstrate that both early activation and late inactivation in the murine AD model require the cleavage of APP at Asp664.
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Reilly JF, Games D, Rydel RE, Freedman S, Schenk D, Young WG, Morrison JH, Bloom FE. Amyloid deposition in the hippocampus and entorhinal cortex: quantitative analysis of a transgenic mouse model. Proc Natl Acad Sci U S A 2003; 100:4837-42. [PMID: 12697936 PMCID: PMC153642 DOI: 10.1073/pnas.0330745100] [Citation(s) in RCA: 117] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Various transgenic mouse models of Alzheimer's disease (AD) have been developed that overexpress mutant forms of amyloid precursor protein in an effort to elucidate more fully the potential role of beta-amyloid (A beta) in the etiopathogenesis of the disease. The present study represents the first complete 3D reconstruction of A beta in the hippocampus and entorhinal cortex of PDAPP transgenic mice. A beta deposits were detected by immunostaining and thioflavin fluorescence, and quantified by using high-throughput digital image acquisition and analysis. Quantitative analysis of amyloid load in hippocampal subfields showed a dramatic increase between 12 and 15 months of age, with little or no earlier detectable deposition. Three-dimensional reconstruction in the oldest brains visualized previously unrecognized sheets of A beta coursing through the hippocampus and cerebral cortex. In contrast with previous hypotheses, compact plaques form before significant deposition of diffuse A beta, suggesting that different mechanisms are involved in the deposition of diffuse amyloid and the aggregation into plaques. The dentate gyrus was the hippocampal subfield with the greatest amyloid burden. Sublaminar distribution of A beta in the dentate gyrus correlated most closely with the termination of afferent projections from the lateral entorhinal cortex, mirroring the selective vulnerability of this circuit in human AD. This detailed temporal and spatial analysis of A beta and compact amyloid deposition suggests that specific corticocortical circuits express selective, but late, vulnerability to the pathognomonic markers of amyloid deposition, and can provide a basis for detecting prior vulnerability factors.
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Rapoport SI. Coupled reductions in brain oxidative phosphorylation and synaptic function can be quantified and staged in the course of Alzheimer disease. Neurotox Res 2003; 5:385-98. [PMID: 14715441 DOI: 10.1007/bf03033167] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
In vivo, post-mortem and biopsy data suggest that coupled declines occur in brain synaptic activity and brain energy consumption during the evolution of Alzheimer disease. In the first stage of these declines, changes in synaptic structure and function reduce neuronal energy demand and lead to potentially reversible downregulation of oxidative phosphorylation (OXPHOS) within neuronal mitochondria. At this stage, measuring brain glucose metabolism or brain blood flow in patients, using positron emission tomography (PET), shows that the brain can be almost normally activated in response to stimulation. Thus, therapy at this stage should be designed to re-establish synaptic integrity or prevent its further deterioration. As disease progresses, neurofibrillary tangles with abnormally phosphorylated tau protein accumulate within neuronal cytoplasm, to the point that they co-opt the nonphosphorylated tau necessary for axonal transport of mitochondria between the cell nucleus and the synapse. In this second stage, severe energy depletion and other pathological processes associated with irreversibly downregulated OXPHOS lead to cell death, and the brain cannot normally respond to functional stimulation.
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Affiliation(s)
- Stanley I Rapoport
- Brain Physiology and Metabolism Sections, Bldg. 10, Rm. 6N202, National Institute on Aging, National Institutes of Health, Bethesda, MD 20892, USA.
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Frenkel D, Solomon B. Filamentous phage as vector-mediated antibody delivery to the brain. Proc Natl Acad Sci U S A 2002; 99:5675-9. [PMID: 11960022 PMCID: PMC122830 DOI: 10.1073/pnas.072027199] [Citation(s) in RCA: 120] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Early diagnosis of Alzheimer's disease is prevented by lack of means to visualize and target beta amyloid plaques in the brains of affected people. There are many methods of detecting amyloid plaques by staining postmortem brain tissue, but none are available for monitoring in living patients. We propose anti-beta amyloid antibodies as a highly specific probe to monitor amyloid plaque formation in living patients. Intranasal administration of filamentous phage as delivery vector of anti-beta amyloid antibody fragment into Alzheimer's APP transgenic mice enables in vivo targeting of beta amyloid plaques. The plaques were co-visualized both by thioflavin-S and fluorescent-labeled anti-phage antibodies in the olfactory bulb and the hippocampus region. The genetically engineered filamentous bacteriophage proved to be an efficient and nontoxic viral delivery vector to the brain, offering an obvious advantage over other mammalian vectors. The ability to image A beta deposits in vivo would arguably provide the most useful diagnostic and monitoring test for early diagnosis of Alzheimer's disease.
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Affiliation(s)
- Dan Frenkel
- Department of Molecular Microbiology and Biotechnology, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Ramat Aviv, Tel Aviv 69978, Israel
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