Mounting evidence suggests that the neuronal cell membrane is the main site of oligomer-mediated neuronal toxicity of amyloid-β peptides in Alzheimer's disease. To gain a detailed understanding of the mutual interference of amyloid-β oligomers and the neuronal membrane, we carried out microseconds of all-atom molecular dynamics (MD) simulations on the dimerization of amyloid-β (Aβ)42 in the aqueous phase and in the presence of a lipid bilayer mimicking the in vivo composition of neuronal membranes. The dimerization in solution is characterized by a random coil to β-sheet transition that seems on pathway to amyloid aggregation, while the interactions with the neuronal membrane decrease the order of the Aβ42 dimer by attenuating its propensity to form a β-sheet structure. The main lipid interaction partners of Aβ42 are the surface-exposed sugar groups of the gangliosides GM1. As the neurotoxic activity of amyloid oligomers increases with oligomer order, these results suggest that GM1 is neuroprotective against Aβ-mediated toxicity.

• Klíčová slova
• Alzheimer’s disease, amyloid-β, molecular dynamics, neuronal membrane, transition network,
• MeSH
• amyloid chemie   MeSH
• amyloidní beta-protein chemie   metabolismus   MeSH
• buněčná membrána metabolismus   MeSH
• G(M1) gangliosid metabolismus   MeSH
• konformace proteinů MeSH
• lidé MeSH
• lipidové dvojvrstvy metabolismus   MeSH
• multimerizace proteinu * MeSH
• neurony metabolismus   MeSH
• simulace molekulární dynamiky MeSH
• vazba proteinů MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• amyloid MeSH
• amyloidní beta-protein MeSH
• G(M1) gangliosid MeSH
• lipidové dvojvrstvy MeSH

Amyloid β peptides appear to play a role in physiological processes; however, they are also involved in the pathogenesis of Alzheimer disease. Their actions under normal conditions are probably mediated by soluble monomeric L-isoforms at low concentrations, perhaps via highly specific interactions. On the contrary, toxic effects of aggregated natural L-isoforms/synthetic D-isoforms on membranes are very similar, but synthetic reverse/random L: -isoforms without pronounced aggregation properties are not toxic. Our previous work reported interactions of non-aggregated/aggregated L-isoforms of amyloid β peptides 1-40/1-42 with racemic 24-hydroxycholesterol. In this study, stereospecificity in the interactions of natural 24(S)hydroxycholesterol (cerebrosterol) or synthetic 24(R)hydroxycholesterol with soluble fragment 1-40 was evaluated by means of an in vitro test based on increased vulnerability of the hemicholinium-3 sensitive high-affinity choline uptake system in rat hippocampal cholesterol-depleted synaptosomes to the actions of amyloid β; computational simulations were also performed. Our results suggest that: (1) 24(S)hydroxycholesterol interacts with L-peptide 1-40 but not with the reverse L-peptide 40-1, (2) 24(R)hydroxycholesterol does not interact with L-peptide 1-40 or reverse 40-1, and (3) both enantiomers can probably interact with D-peptide 1-40. Therefore, the binding of 24(S)hydroxycholesterol is not fully stereospecific and the interaction could not reflect a physiological mechanism. Data from the computational simulation indicate that the hydrophobic core of the amyloid β molecule interacts with the hydrophobic part of 24(S)hydroxycholesterol, but no hydrogen bonds with high stability were found. Using this procedure, globular amyloid β could retain 24(S)hydroxycholesterol and thus contribute to its pathological accumulation in the brains of patients with Alzheimer disease.

• MeSH
• amyloidní beta-protein metabolismus   MeSH
• hipokampus metabolismus   MeSH
• hydroxycholesteroly metabolismus   MeSH
• krysa rodu Rattus MeSH
• peptidové fragmenty metabolismus   MeSH
• potkani Wistar MeSH
• vazba proteinů MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 24-hydroxycholesterol MeSH Prohlížeč
• amyloid beta-protein (1-40) MeSH Prohlížeč
• amyloidní beta-protein MeSH
• hydroxycholesteroly MeSH
• peptidové fragmenty MeSH

Alzheimer's Disease (AD) is a neurodegenerative disorder with an increasing impact on society. Because currently available therapy has only a short-term effect, a huge number of novel compounds are developed every year exploiting knowledge of the various aspects of AD pathophysiology. To better address the pathological complexity of AD, one of the most extensively pursued strategies by medicinal chemists is based on Multi-target-directed Ligands (MTDLs). Donepezil is one of the currently approved drugs for AD therapy acting as an acetylcholinesterase inhibitor. In this review, we have made an extensive literature survey focusing on donepezil-derived MTDL hybrids primarily targeting on different levels cholinesterases and amyloid beta (Aβ) peptide. The targeting includes direct interaction of the compounds with Aβ, AChE-induced Aβ aggregation, inhibition of BACE-1 enzyme, and modulation of biometal balance thus impeding Aβ assembly.

• Klíčová slova
• Acetylcholinesterase, Alzheimer`s disease, amyloid-β, beta-secretase 1, biometal, butyrylcholinesterase, multitarget directed ligands, neuroprotection.,
• MeSH
• acetylcholinesterasa metabolismus   MeSH
• Alzheimerova nemoc farmakoterapie   metabolismus   MeSH
• amyloidní beta-protein metabolismus   MeSH
• cholinesterasové inhibitory farmakologie   terapeutické užití   MeSH
• donepezil analogy a deriváty   MeSH
• lidé MeSH
• patologická konformace proteinů farmakoterapie   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Názvy látek
• acetylcholinesterasa MeSH
• amyloidní beta-protein MeSH
• cholinesterasové inhibitory MeSH
• donepezil MeSH

β-Amyloid (Aβ) oligomers are neurotoxic and implicated in Alzheimer's disease. Neuronal plasma membranes may mediate formation of Aβ oligomers in vivo. Membrane components sphingomyelin and GM1 have been shown to promote aggregation of Aβ; however, these studies were performed under extreme, non-physiological conditions. We demonstrate that physiological levels of GM1 , organized in nanodomains do not seed oligomerization of Aβ40 monomers. We show that sphingomyelin triggers oligomerization of Aβ40 and that GM1 is counteractive thus preventing oligomerization. We propose a molecular explanation that is supported by all-atom molecular dynamics simulations. The preventive role of GM1 in the oligomerization of Aβ40 suggests that decreasing levels of GM1 in the brain, for example, due to aging, could reduce protection against Aβ oligomerization and contribute to the onset of Alzheimer's disease.

• Klíčová slova
• Alzheimer's disease, amyloid beta-peptides, diffusion coefficients, fluorescence spectroscopy, neuroprotectives,
• MeSH
• amyloidní beta-protein antagonisté a inhibitory   metabolismus   MeSH
• G(M1) gangliosid chemie   farmakologie   MeSH
• sfingomyeliny chemie   farmakologie   MeSH
• simulace molekulární dynamiky MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• amyloidní beta-protein MeSH
• G(M1) gangliosid MeSH
• sfingomyeliny MeSH

The interaction of amyloid β-peptide (Aβ) with the iron-storage protein ferritin was studied in vitro. We have shown that Aβ during fibril formation process is able to reduce Fe(III) from the ferritin core (ferrihydrite) to Fe(II). The Aβ-mediated Fe(III) reduction yielded a two-times-higher concentration of free Fe(II) than the spontaneous formation of Fe(II) by the ferritin itself. We suggest that Aβ can also act as a ferritin-specific metallochaperone-like molecule capturing Fe(III) from the ferritin ferrihydrite core. Our observation may partially explain the formation of Fe(II)-containing minerals in human brains suffering by neurodegenerative diseases.

• Klíčová slova
• Alzheimer’s disease, Aβ, Ferritin, Iron reduction, Magnetite, Metallochaperone,
• MeSH
• amyloid chemie   MeSH
• amyloidní beta-protein chemie   metabolismus   MeSH
• ferritin chemie   metabolismus   MeSH
• lidé MeSH
• oxidace-redukce MeSH
• železo metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• amyloid MeSH
• amyloidní beta-protein MeSH
• ferritin MeSH
• železo MeSH

Amyloid β is considered a key player in the development and progression of Alzheimer's disease (AD). Many studies investigating the effect of statins on lowering cholesterol suggest that there may be a link between cholesterol levels and AD pathology. Since cholesterol is one of the most abundant lipid molecules, especially in brain tissue, it affects most membrane-related processes, including the formation of the most dangerous form of amyloid β, Aβ42. The entire Aβ production system, which includes the amyloid precursor protein (APP), β-secretase, and the complex of γ-secretase, is highly dependent on membrane cholesterol content. Moreover, cholesterol can affect amyloidogenesis in many ways. Cholesterol influences the stability and activity of secretases, but also dictates their partitioning into specific cellular compartments and cholesterol-enriched lipid rafts, where the amyloidogenic machinery is predominantly localized. The most complicated relationships have been found in the interaction between cholesterol and APP, where cholesterol affects not only APP localization but also the precise character of APP dimerization and APP processing by γ-secretase, which is important for the production of Aβ of different lengths. In this review, we describe the intricate web of interdependence between cellular cholesterol levels, cholesterol membrane distribution, and cholesterol-dependent production of Aβ, the major player in AD.

• Klíčová slova
• Amyloid precursor protein, Amyloid β, Amyloidogenesis, Cholesterol, Secretase,
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

The overproduction of β-amyloid (Aβ) fragments in transgenic APPswe/PS1dE9 mice results in formation of amyloid deposits in the cerebral cortex and hippocampus starting around four months of age and leading to cognitive impairment much later. We have previously found an age and transgene-dependent weakening of muscarinic receptor-mediated transmission that was not present in young (6-10-week-old) animals but preceded both amyloid deposits and cognitive deficits. Now we investigated immediate and prolonged in vitro effects of non-aggregated Aβ(1-42) on coupling of individual muscarinic receptor subtypes expressed in CHO (Chinese hamster ovary) cells and their underlying mechanisms. Immediate application of 1 μM Aβ(1-42) had no effect on the binding of the muscarinic antagonist N-methylscopolamine or the agonist carbachol. In contrast, 4-day treatment of CHO cells expressing the M1 muscarinic receptor with 100 nM Aβ(1-42) significantly changed the binding characteristics of the muscarinic agonist carbachol and reduced the extent of the M1 receptor-stimulated breakdown of phosphatidylinositol while it did not demonstrate overt toxic effects. The treatment had no influence on the expression of either G-proteins or muscarinic receptors. In concert, we found no change in the gene expression of muscarinic receptor subtypes and gene or protein expression of the G(s), G(q/11), and G(i/o) G-proteins in the cerebral cortex of young adult APPswe/PS1dE9 mice that demonstrate high concentrations of soluble Aβ(1-42) and impaired muscarinic receptor-mediated G-protein activation. Our results provide strong evidence that the initial injurious effects of Aβ(1-42) on M1 muscarinic receptor-mediated transmissionis is due to compromised coupling of the receptor with G(q/11) G-protein.

• MeSH
• amyloidní beta-protein antagonisté a inhibitory   metabolismus   MeSH
• CHO buňky MeSH
• Cricetulus MeSH
• křečci praví MeSH
• kultivované buňky MeSH
• lidé MeSH
• myši transgenní MeSH
• myši MeSH
• peptidové fragmenty antagonisté a inhibitory   metabolismus   MeSH
• receptor muskarinový M1 metabolismus   MeSH
• receptory spřažené s G-proteiny antagonisté a inhibitory   metabolismus   MeSH
• rozpřahující látky farmakologie   MeSH
• vazba proteinů účinky léků   fyziologie   MeSH
• zvířata MeSH
• Check Tag
• křečci praví MeSH
• lidé MeSH
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• amyloid beta-protein (1-42) MeSH Prohlížeč
• amyloidní beta-protein MeSH
• peptidové fragmenty MeSH
• receptor muskarinový M1 MeSH
• receptory spřažené s G-proteiny MeSH
• rozpřahující látky MeSH

In this perspective we summarize current knowledge of the effect of monosialoganglioside GM1 on the membrane-mediated aggregation of the β-amyloid (Aβ) peptide. GM1 has been suggested to be actively involved in the development of Alzheimer's disease due to its ability to seed the aggregation of Aβ. However, GM1 is known to be neuroprotective against Aβ-induced toxicity. Here we suggest that the two scenarios are not mutually exclusive but rather complementary, and might depend on the organization of GM1 in membranes. Improving our understanding of the molecular details behind the role of gangliosides in neurodegenerative amyloidoses might help in developing disease-modifying treatments.

• MeSH
• amyloidní beta-protein chemie   metabolismus   MeSH
• G(M1) gangliosid chemie   metabolismus   MeSH
• lidé MeSH
• mozek metabolismus   MeSH
• patologická konformace proteinů metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• amyloidní beta-protein MeSH
• G(M1) gangliosid MeSH

The accumulation of amyloid-β (Aβ) peptide is thought to be a major causative mechanism of Alzheimer's disease. Aβ accumulation could be caused by dysregulated processing of amyloid precursor protein, yielding excessive amounts of Aβ, and/or by inefficient proteolytic degradation of the peptide itself. Several proteases have been described as Aβ degradation enzymes, most notably metalloendopeptidases, aspartic endopeptidases, and some exopeptidases. Recently a report suggested that another metallopeptidase, glutamate carboxypeptidase II (GCPII), can also cleave Aβ. GCPII is a zinc exopeptidase that cleaves glutamate from N-acetyl-L-aspartyl-L-glutamate in the central nervous system and from pteroylpoly-γ-glutamate in the jejunum. GCPII has been proposed as a promising therapeutic target for disorders caused by glutamate neurotoxicity. However, an Aβ-degrading activity of GCPII would compromise potential pharmaceutical use of GCPII inhibitors, because the enzyme inhibition might lead to increased Aβ levels and consequently to Alzheimer's disease. Therefore, we analyzed the reported Aβ-degrading activity of GCPII using highly purified recombinant enzyme and synthetic Aβ. We did not detect any Aβ degradation activity of GCPII or its homologue even under prolonged incubation at a high enzyme to substrate ratio. These results are in good agreement with the current detailed structural understanding of the substrate specificity and enzyme-ligand interactions of GCPII.

• Klíčová slova
• Alzheimer's disease, PSMA, depsipeptide, disaggregation, exopeptidase, substrate specificity,
• MeSH
• amyloidní beta-protein chemie   metabolismus   MeSH
• antigeny povrchové genetika   metabolismus   MeSH
• biokatalýza účinky léků   MeSH
• dipeptidy metabolismus   MeSH
• glutamátkarboxypeptidasa II antagonisté a inhibitory   genetika   metabolismus   MeSH
• hmotnostní spektrometrie MeSH
• hydrolýza MeSH
• katalytická doména MeSH
• lidé MeSH
• molekulární struktura MeSH
• neprilysin genetika   metabolismus   MeSH
• organofosforové sloučeniny farmakologie   MeSH
• peptidové fragmenty chemie   metabolismus   MeSH
• proteolýza MeSH
• rekombinantní proteiny metabolismus   MeSH
• substrátová specifita MeSH
• tritium MeSH
• vysokoúčinná kapalinová chromatografie MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 2-(phosphonomethyl)pentanedioic acid MeSH Prohlížeč
• amyloid beta-protein (1-42) MeSH Prohlížeč
• amyloidní beta-protein MeSH
• antigeny povrchové MeSH
• dipeptidy MeSH
• FOLH1 protein, human MeSH Prohlížeč
• glutamátkarboxypeptidasa II MeSH
• isospaglumic acid MeSH Prohlížeč
• neprilysin MeSH
• organofosforové sloučeniny MeSH
• peptidové fragmenty MeSH
• rekombinantní proteiny MeSH
• tritium MeSH

Identification and evaluation of small changes in β-amyloid peptide (Aβ) levels in cerebrospinal fluid is of crucial importance for early detection of Alzheimer's disease. Microfluidic detection methods enable effective preconcentration of Aβ using magnetic microparticles coated with Aβ antibodies. Poly(glycidyl methacrylate) microspheres are coated with α-amino-ω-methoxy-PEG5000 /α-amino-ω-Boc-NH-PEG5000 Boc groups deprotected and NH2 succinylated to introduce carboxyl groups. Capillary electrophoresis with laser-induced fluorescence detection confirms the efficient capture of Aβ 1-40 peptides on the microspheres with immobilized monoclonal anti-Aβ 6E10. The capture specificity is confirmed by comparing Aβ 1-40 levels on the anti-IgG-immobilized particles used as a control.

• Klíčová slova
• CE-LIF detection, functionalization, magnetic, microspheres, β-amyloid peptides,
• MeSH
• adsorpce MeSH
• amyloidní beta-protein izolace a purifikace   MeSH
• chromatografie afinitní MeSH
• elektroforéza kapilární MeSH
• imunoglobulin G metabolismus   MeSH
• kyseliny karboxylové chemie   MeSH
• kyseliny polymethakrylové chemie   MeSH
• magnetické jevy MeSH
• mikrosféry * MeSH
• mikroskopie atomárních sil MeSH
• peptidové fragmenty izolace a purifikace   MeSH
• polyethylenglykoly chemie   MeSH
• skot MeSH
• termogravimetrie MeSH
• velikost částic MeSH
• zvířata MeSH
• Check Tag
• skot MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• amyloid beta-protein (1-40) MeSH Prohlížeč
• amyloidní beta-protein MeSH
• imunoglobulin G MeSH
• kyseliny karboxylové MeSH
• kyseliny polymethakrylové MeSH
• peptidové fragmenty MeSH
• polyethylenglykoly MeSH
• polyglycidyl methacrylate MeSH Prohlížeč