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  • 1
    Electronic Resource
    Electronic Resource
    Metabotropic Glutamate Receptor Subtype mGluR1α Stimulates the Secretion of the Amyloid β-Protein Precursor Ectodomain (1997)
    Oxford, UK : Blackwell Science Ltd
    Journal of neurochemistry 69 (1997), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: To examine the effects of glutamatergic neurotransmission on amyloid processing, we stably expressed the metabotropic glutamate receptor subtype 1α (mGluR1α) in HEK 293 cells. Both glutamate and the selective metabotropic agonist 1-amino-1,3-cyclopentanedicarboxylic acid (ACPD) rapidly increased phosphatidylinositol (PI) turnover four- to fivefold compared with control cells that were transfected with the expression vector alone. Increased PI turnover was effectively blocked by the metabotropic antagonist α-methyl-4-carbophenylglycine (MCPG), indicating that heterologous expression of mGluR1α resulted in efficient coupling of the receptors to G protein and phospholipase C activation. Stimulation of mGluR1α with glutamate, quisqualate, or ACPD rapidly increased secretion of the APP ectodomain (APPs); these effects were blocked by MCPG. The metabotropic receptors were coupled to APP processing by protein kinases and by phospholipase A2 (PLA2), and melittin, a peptide that stimulates PLA2, potently increased APPs secretion. These data indicate that mGluR1α can be involved in the regulation of APP processing. Together with previous findings that muscarinic and serotonergic receptor subtypes can increase the secretion of the APP ectodomain, these observations support the concept that proteolytic processing of APP is under the control of several major neurotransmitters.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1471-4159.1997.69020704.x
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  • 2
    Electronic Resource
    Electronic Resource
    Preface (1993)
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 695 (1993), S. 0 
    Details
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Notes: This volume contains the papers and poster abstracts compiled for the seventh meeting of the International Study Group on the Pharmacology of Memory Disorders Associated with Aging (ISG), that took place in Zürich, Switzerland, on February 12–14, 1993. The ISG was founded 14 years ago in the belief that the development of effective treatments for Alzheimer's disease (AD) and other dementias would be accelerated by periodic meetings of scientists and physicians from around the world who are actively working on issues related to dementia. There have been six previous “Zurich Meetings”—in 1979, 1981, 1984, 1987, 1989, and 1991. The proceedings of the second ISB meeting were published by Raven Press in 1982 (Alzheimer's Disease: A Report of Progress in Research; Corkin, Davis, Growdon, Usdin, and Wurtman, editors); the proceedings of the fourth ISG meeting were published by Springer-Verlag in 1988 as Supplement 24 of the Journal of Neural Transmission (Topics in the Basic and Clinical Science of Dementia; Wurtman, Corkin, and Growdon, editors); the proceedings of the fifth ISB meeting were published by Raven Press in 1990 (Alzheimer's Disease, Advances in Neurology, Volume 51; Wurtman, Corkin, Growdon, and fitter-Walker, editors); and the proceedings of the sixth ISG meeting were published by the New York Academy of Sciences in 1992 (Aging and Alzheimer's Disease, Volume 640; Growdon, Corkin, fitter-Walker, and Wurtman, editors).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1749-6632.1993.tb23017.x
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  • 3
    Electronic Resource
    Electronic Resource
    Regulation of Amyloid Precursor Protein Release By Protein Kinase C in Swiss 3T3 Fibroblasts (1993)
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 695 (1993), S. 0 
    Details
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Notes: Release of the amyloid precursor protein (APP) of Alzheimer's disease from Swiss 3T3 fibroblasts was stimulated in a concentration-dependent manner by phorbol 12-myristate 13-acetate. In fibroblasts overexpressing protein kinase Co (PKCα), the EC50 for this response was 7 nM, while in control cells the EC50 was 63 nM. The effect of PMA was inhibited by the PKC antagonist H-7 in control cells, but not in cells that overexpressed PKCα. Basal release of APP was higher in cells that overexpressed PKCα, and was not affected by the phosphatase inhibitor okadaic acid, although this compound doubled APP release from control cells. The results suggest that PKCα regulates APP processing in mammalian cells. Alterations in the activity of PKC have been reported to occur in Alzheimer's disease and might potentially contribute to abnormalities of APP metabolism characteristic of this disorder.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1749-6632.1993.tb23040.x
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  • 4
    Electronic Resource
    Electronic Resource
    Receptor-coupled Amyloid Precursor Protein Processing (1993)
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 695 (1993), S. 0 
    Details
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Notes: The family of β-amyloid protein precursors (APP) can be processed via several alternative proteolytic pathways. Some generate potentially amyloidogenic AFP derivatives, whereas others preclude the formation of such fragments. The cellular mechanisms regulating the relative activities of these pathways are thus important in determining the factors contributing to the formation of amyloidogenic APP derivatives. In order to investigate whether cell-surface receptor activity can regulate APP processing, HEK 293 cell lines stably expressing human muscarinic acetylcholine receptors (mAChR; subtypes m1, m2, m3, m4) were stimulated with the muscarinic agonist carbachol, and the release of APP derivatives was measured. Carbachol increased the release of large amino-terminal APP-fragments 4-to 6-fold in cell lines expressing the m1 or m3 receptors but not in those expressing m2 or m4 subtypes. This increase was blocked by various protein kinase inhibitors and mimicked by phorbol esters, indicating that it is mediated by protein kinase activation, presumably by protein kinase C (PKC). To determine whether additional cell-surface receptor types linked to this signal transduction pathway could also regulate APP processing, we stimulated differentiated PC-12 cells with bradykinin and found that this neuropeptide also increased the secretion of amino-terminal APP derivatives. We next investigated the possibility that neuronal depolarization might affect APP processing in mammalian brain. Electrically stimulated rat hippocampal slices released two times more amino-terminal APP derivatives than unstimulated control slices. This release increased with increasing stimulation frequencies in the physiological firing range of hippocampal pyramidal cells, and was blocked by tetrodotoxin. These results suggest that, in brain, APP processing is regulated by neuronal activity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1749-6632.1993.tb23039.x
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  • 5
    Electronic Resource
    Electronic Resource
    The novel cytosolic RING finger protein dactylidin is up-regulated in brains of patients with Alzheimer's disease (2005)
    Oxford, UK : Blackwell Science Ltd
    European journal of neuroscience 21 (2005), S. 0 
    Details
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Alzheimer's disease (AD) is characterized by a progressive degeneration of neurons along with deposition of amyloid plaques and the formation of neurofibrillary tangles. Neurodegeneration in AD follows both a spatial pattern of selective vulnerability and temporal staging of affected neurons. In order to address transcriptional changes associated with this selective vulnerability, we used subtractive hybridization of transcripts derived from human frontal cortex, which degenerates in late stages of AD, against transcripts of the inferior temporal cortex, which is affected both heavily and early in the course of AD. Moreover, we compared these to brain sections obtained from age-matched control subjects. We isolated a differentially expressed novel gene encoding a polypeptide that contained an amino-terminal C3HC4 RING finger domain, called dactylidin. It is ubiquitously expressed in all tissues examined and in situ hybridization of mouse brain sections revealed specific expression in neurons. Further, heterologous expression studies revealed a cytoplasmic localization of dactylidin and as all known cytoplasmic RING finger proteins function as ubiquitin protein ligases, an E3-like ligase function of dactylidin is probable. However, the up-regulation of dactylidin in highly vulnerable brain tissues of AD patients was confirmed by a quantitative PCR approach, suggesting that dactylidin may function early in the progression of neurodegenerative diseases.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1460-9568.2005.03977.x
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  • 6
    Electronic Resource
    Electronic Resource
    Oligodendroglial tau filament formation in transgenic mice expressing G272V tau (2001)
    Oxford, UK : Blackwell Science Ltd
    European journal of neuroscience 13 (2001), S. 0 
    Details
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Genetic evidence indicates that several mutations in tau, including G272V, are linked to frontotemporal dementia with parkinsonism. We expressed this mutation in mouse brains by combining a prion protein promoter-driven expression system with an autoregulatory transactivator loop that resulted in high expression of human G272V tau in neurons and in oligodendrocytes. We show that G272V tau can form filaments in murine oligodendrocytes. Electron microscopy established that the filaments were either straight or had a twisted structure; these were 17–20 nm wide and had a periodicity of ≈ 75 nm. Filament formation was associated with tau phosphorylation at distinct sites, including the AT8 epitope 202/205 in vivo. Immunogold electron microscopy of sarcosyl-extracted spinal cords from G272V transgenic mice using phosphorylation-dependent antibodies AT8 or AT100 identified several sparsely gold-labelled 6-nm filaments. In the spinal cord, fibrillary inclusions were also identified by thioflavin-S fluorescent microscopy in oligodendrocytes and motor neurons. These results establish that expression of the G272V mutation in mice causes oligodendroglial fibrillary lesions that are similar to those seen in human tauopathies.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.0953-816x.2001.01604.x
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  • 7
    Electronic Resource
    Electronic Resource
    Glucocorticoid-induced impairment of declarative memory retrieval is associated with reduced blood flow in the medial temporal lobe (2003)
    Oxford, UK : Blackwell Science, Ltd
    European journal of neuroscience 17 (2003), S. 0 
    Details
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Previous work indicates that stress levels of circulating glucocorticoids can impair retrieval of declarative memory in human subjects. Several studies have reported that declarative memory retrieval relies on the medial temporal lobe. The present study used \mathrm{H}^{15}_{2}O-positron emission tomography to investigate whether acutely elevated glucocorticoid levels affect regional cerebral blood flow in the medial temporal lobe, as well as in other brain regions, during declarative memory retrieval in healthy male human subjects. When measured over four different declarative memory retrieval tasks, a single, stress-level dose of cortisone (25 mg) administered orally 1 h before retention testing, induced a large decrease in regional cerebral blood flow in the right posterior medial temporal lobe, the left visual cortex and the cerebellum. The decrease in the right posterior medial temporal lobe was maximal in the parahippocampal gyrus, a region associated with successful verbal memory retrieval. Cortisone administration also significantly impaired cued recall of word pairs learned 24 h earlier, while drug effects on performance in the other tasks (verbal recognition, semantic generation and categorization) were not significant. The present results provide further evidence that acutely elevated glucocorticoid levels can impair declarative memory retrieval processes and suggest that such impairments may be related to a disturbance of medial temporal lobe function.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1460-9568.2003.02542.x
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  • 8
    Electronic Resource
    Electronic Resource
    Diversity, developmental regulation and distribution of murine PR55/B subunits of protein phosphatase 2A (2002)
    Oxford, UK : Blackwell Science, Ltd
    European journal of neuroscience 16 (2002), S. 0 
    Details
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Protein phosphatase (PP2A) 2A is a hetero-trimeric holoenzyme that consists of a core dimer composed of a catalytic subunit that is tightly complexed with the scaffolding subunit PR65/A. This core dimer associates with variable regulatory subunits of the PR55/B, PR61/B′, PR72/B′′ and PR93/PR110/B′′′ families. As PP2A holoenzymes containing PR55/B have been shown to be involved in the pathogenesis of Alzheimer's disease, we characterized the PR55/B family with particular emphasis on its distribution and expression in the brain. We determined the genomic organization of all members of the PR55/B family and cloned their murine cDNAs. Thereby, two novel splice variants of PR55/Bβ were identified. In addition, Northern blot analysis revealed multiple transcripts for the different PR55 subunits, suggesting a higher variability within the PR55 family. In situ hybridization analysis revealed that all PR55/B subunits were widely expressed in the brain. PR55/Bα and Bβ protein expression varies significantly in areas of the brain affected by neurodegenerative diseases such as the hippocampus or cerebellum. At the cellular level, PR55/Bβ protein expression was confined to neurons, whereas PR55/Bα was also expressed in activated astrocytes indicating that the PR55 isoforms confer a different function to the holoenzyme complex. As PP2A dysfunction has been demonstrated to contribute to various human diseases, dissecting the PP2A holoenzyme and its particular function in different cell types will assist in the development of novel therapeutic strategies.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1460-9568.2002.02274.x
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  • 9
    Electronic Resource
    Electronic Resource
    Phospholipid and Phospholipid Metabolites in Rat Frontal Cortex Are Decreased following Nucleus Basalis Lesions (1993)
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 695 (1993), S. 0 
    Details
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Notes: Membrane phospholipid metabolism is abnormal in Alzheimer's disease (AD) brain. Phosphatidylcholine and phosphatidylethanolamine levels are decreased as are choline and ethanolamine, while glycerophosphocholine (GPC) and glycerophosphoethanolamine are increased.1 To develop a rat model for these changes, we examined the effects of unilateral lesion of the cholinergic nucleus basalis (nBM) with ibotenic acid (10 mg/ml in PBS, 0.5 μl) and sham lesion on frontocortical phospholipid, choline and GPC. After one week, choline acetyltransferase activity in frontal cortex was decreased (26%, p 〈 0.005, n = 14) on the nBM ibotenate-lesion side relative to the contralateral side, while there were no differences following the nBM sham-lesion. Levels of membrane phospholipids (nmol/mg protein) in adjacent frontal cortex sections exhibited concomitant decreases (13%, p 〈 0.05, n = 14) on the nBM ibotenate-lesion side, while there were no differences following the nBM sham-lesion. Tissue nBM ibotenate-lesion frontocortical choline and GPC levels were also decreased relative to those in control tissues (choline: 21%, p 〈 0.05, n = 14; GPC: 10%,p 〈 0.05, n = 14), while nBM sham-lesion showed no effect. Muscarinic receptor sensitivity in frontal cortex following nBM ibotenate-lesion was increased, as measured by carbachol-sdmulated inositol phosphate production (p 〈 0.001, n = 12), indicating that increased receptor mediated phospholipid hydrolysis in cortex may occur following nBM ibotenate-lesion. These data suggest that impaired cholinergic transmission alters phospholipid metabolism in cholinergic target regions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1749-6632.1993.tb23060.x
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  • 10
    Electronic Resource
    Electronic Resource
    Generation of antibodies specific for β-amyloid by vaccination of patients with Alzheimer disease (2002)
    [s.l.] : Nature Publishing Group
    Nature medicine 8 (2002), S. 1270-1275 
    Details
    ISSN: 1546-170X
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Medicine
    Notes: [Auszug] To characterize antibodies produced in humans in response to Aβ42 vaccination, we carried out immunohistochemical examinations of the brains of both transgenic mice and human patients with β-amyloid pathology. We collected sera from patients with Alzheimer disease who received a primary ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/nm783
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