Peptide Blockers of the Inhibition of Neuronal Nicotinic Acetylcholine Receptors by Amyloid β

Magdesian, Margaret H.; Nery, Arthur A.; Martins, Ana; Juliano, María A.; Juliano, Luiz; Ulrich, Henning; Ferreira, Sérgio T.

doi:10.1074/jbc.m502406200

Cited by 45 publications

(60 citation statements)

References 35 publications

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“…Magdesian and colleagues [30] have demonstrated that A␤ binds at the interface between the acetylcholine and nicotine binding domains of the ␣7nAChR. Additionally, A␤-evoked Ca 2+ efflux from nerve terminals was not increased after coapplication of nicotine suggesting similar binding sites [31,32].…”

Section: Discussionmentioning

confidence: 96%

Soluble Amyloid-β42 Stimulates Glutamate Release through Activation of the α7 Nicotinic Acetylcholine Receptor

Hascup

2016

JAD

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Abstract. Alzheimer's disease (AD) is an age-related neurodegenerative disorder characterized by progressive memory loss and hippocampal atrophy. Soluble amyloid-␤ (A␤) 42 and plaque accumulation is implicated as the neurotoxic species in this disorder; however, at physiological concentrations (pM-nM), A␤ 42 contributes to neurogenesis, long-term potentiation, and neuromodulation. Because A␤ 42 binds the ␣7 nicotinic acetylcholine receptors (␣7nAChRs) located presynaptically on glutamatergic terminals, involved with hippocampal dependent learning and memory, we examined the effects of the human, monomeric isoform of A␤ 42 on glutamate release in the dentate gyrus (DG), CA3, and CA1, of isoflurane anesthetized, 6-9 month old male C57BL/6J mice. We utilized an enzyme-based microelectrode array selective for L-glutamate measures with fast temporal (4 Hz), low spatial resolution (50 × 100 m) and minimal damage to the surrounding parenchyma (50-100 m). Local application of A␤ 42 (0.01, 0.1, 1.0, and 10.0 M; ∼150 nl; 1-2 Seconds) elicited robust, reproducible glutamate signals in all hippocampal subfields studied. Local application of 0.1 and 1.0 M A␤ 42 significantly increased the average maximal amplitude of glutamate release compared to saline in the DG and CA1. 10.0 M A␤ 42 significantly elevated glutamate release in the DG and CA3, but not in the CA1. Glutamate release was completely attenuated with coapplication of 10.0 M ␣-Bungarotoxin, the potent ␣7nAChR antagonist. Coapplication of 10.0 M tetrodotoxin, indicates A␤ 42-induced glutamate release originates from neuronal rather than glial sources. This study demonstrates that the human, monomeric A␤ 42 isoform evokes glutamate release through the ␣7nAChR and varies across hippocampal subfields.

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Section: Discussionmentioning

confidence: 96%

Soluble Amyloid-β42 Stimulates Glutamate Release through Activation of the α7 Nicotinic Acetylcholine Receptor

Hascup

2016

JAD

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Section: Discussionmentioning

confidence: 99%

“…The display of random peptides on filamentous bacteriophage has allowed the identification of peptides that bind specifically to a variety of targets, including A␤ (25,33,34). Peptides thus identified have been shown to act as agonists or antagonists of various receptors and to mimic the binding sites of physiological receptors (25). Using this approach, we have now identified a cysteine-linked heptapeptide (denoted cSP5) that binds to soluble A␤40/A␤42 and is homologous to the extracellular cysteine-rich domain (FzCRD) present in several members of the Fz family of Wnt receptors.…”

Section: Discussionmentioning

confidence: 99%

“…Biopanning against A␤-Screening of the phage display peptide library was performed as previously described (25). Briefly, A␤40 was diluted to 0.1 g/ml in 50% trifluorethanol/PBS, and 50-l aliquots were dried in the wells of a 96-well plate at 37°C under constant shaking for 16 h. To check the state of aggregation of the samples, the material from one well was extracted and submitted to SDS-PAGE electrophoresis.…”

Section: Methodsmentioning

confidence: 99%

“…The wells were washed six times with PBS, incubated with the corresponding anti-Fz4CRD or anti-Fz5CRD for 1 h, washed, incubated with horseradish peroxidase-conjugated secondary antibody for 1 h, and developed with SuperSignal Femto Substrate (Pierce). Specificity of the binding assay was verified by appropriate controls carried out using wells coated with BSA alone or using a nonspecific peptide (denoted SQI) that does not bind A␤ (25). To calculate the K d for binding of Fz5CRD to A␤, wells of an enzyme-linked immunosorbent assay plate were coated with A␤40 or with different concentrations of Fz5CRD alone (i.e.…”

Section: Methodsmentioning

confidence: 99%

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Amyloid-β Binds to the Extracellular Cysteine-rich Domain of Frizzled and Inhibits Wnt/β-Catenin Signaling

Magdesian

Carvalho²,

Mendes

et al. 2008

Journal of Biological Chemistry

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229

170

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The amyloid-␤ peptide (A␤) plays a major role in neuronal dysfunction and neurotoxicity in Alzheimer disease. However, the signal transduction mechanisms involved in A␤-induced neuronal dysfunction remain to be fully elucidated. A major current unknown is the identity of the protein receptor(s) involved in neuronal A␤ binding. Using phage display of peptide libraries, we have identified a number of peptides that bind A␤ and are homologous to neuronal receptors putatively involved in A␤ interactions. We report here on a cysteine-linked cyclic heptapeptide (denominated cSP5) that binds A␤ with high affinity and is homologous to the extracellular cysteine-rich domain of several members of the Frizzled (Fz) family of Wnt receptors. Based on this homology, we investigated the interaction between A␤ and Fz. The results show that A␤ binds to the Fz cysteine-rich domain at or in close proximity to the Wnt-binding site and inhibits the canonical Wnt signaling pathway. Interestingly, the cSP5 peptide completely blocks A␤ binding to Fz and prevents inhibition of Wnt signaling. These results indicate that the A␤-binding site in Fz is homologous to cSP5 and that this is a relevant target for A␤-instigated neurotoxicity. Furthermore, they suggest that blocking the interaction of A␤ with Fz might lead to novel therapeutic approaches to prevent neuronal dysfunction in Alzheimer disease. Alzheimer disease (AD)2 is a progressive neurodegenerative disorder characterized, in its early stages, by a striking inability to form new memories. Recent work indicates that cognitive and memory impairments in early AD are caused by synaptic dysfunction instigated by pathological assemblies of the amyloid-␤ peptide (A␤) (for recent reviews, see Refs. 1-3). Neuropathological hallmarks of AD include increased brain levels and extracellular build-up of A␤ aggregates, intraneuronal neurofibrillary tangles composed of hyperphosphorylated Tau, and, notably, synaptic loss (1). Despite the fact that A␤ has been strongly implicated in neuronal dysfunction and neurotoxicity in AD, the signal transduction mechanisms involved in the neuronal impact of A␤ remain to be fully elucidated. A major current unknown is the identity of the neuronal receptor(s) that bind A␤ and mediate neuronal dysfunction. Identification of such receptor(s) would provide considerable insight into mechanisms of pathogenesis and might reveal novel opportunities for the development of strategies to combat AD.The Wnt signaling pathway has been recently proposed to play a role in AD (for a review, see Ref. 4). Wnts are secreted glycoproteins that bind to and signal through Frizzled (Fz) receptors and mediate cell-cell communication (5). Wnt signaling regulates a variety of biological processes, including development, cell movement, polarity, axon guidance, and synapse formation (6). Different types of Wnt⅐Fz complexes may signal through the so-called canonical or noncanonical Wnt pathways. Canonical Wnt/Fz signaling results in stabilization and increased intracellular levels of ␤-cate...

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The Use of Phage Display in Neurobiology

Bradbury

2010

CP Neuroscience

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Phage display has been extensively used to study protein-protein interactions, receptor- and antibody-binding sites, and immune responses, to modify protein properties, and to select antibodies against a wide range of different antigens. In the format most often used, a polypeptide is displayed on the surface of a filamentous phage by genetic fusion to one of the coat proteins, creating a chimeric coat protein, and coupling phenotype (the protein) to genotype (the gene within). As the gene encoding the chimeric coat protein is packaged within the phage, selection of the phage on the basis of the binding properties of the polypeptide displayed on the surface simultaneously results in the isolation of the gene encoding the polypeptide. This unit describes the background to the technique, and illustrates how it has been applied to a number of different problems, each of which has its neurobiological counterparts. Although this overview concentrates on the use of filamentous phage, which is the most popular platform, other systems are also described.

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Peptide Blockers of the Inhibition of Neuronal Nicotinic Acetylcholine Receptors by Amyloid β

Cited by 45 publications

References 35 publications

Soluble Amyloid-β42 Stimulates Glutamate Release through Activation of the α7 Nicotinic Acetylcholine Receptor

Soluble Amyloid-β42 Stimulates Glutamate Release through Activation of the α7 Nicotinic Acetylcholine Receptor

Amyloid-β Binds to the Extracellular Cysteine-rich Domain of Frizzled and Inhibits Wnt/β-Catenin Signaling

The Use of Phage Display in Neurobiology

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