On-line high-performance liquid chromatography/mass spectrometric investigation of amyloid-β peptide variants found in Alzheimer's disease

Thompson, Andrew J.; Lim, Teck Kwang; Barrow, Colin J.

doi:10.1002/(sici)1097-0231(19991215)13:23<2348::aid-rcm797>3.0.co;2-j

Cited by 12 publications

(10 citation statements)

References 22 publications

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“…Many techniques and protocols were developed to increase the sensitivity to different forms of A␤, especially the A␤ pE peptides (34,35). Equipped with a set of novel antibodies, Saido et al (15) showed by immunohistochemical and biochemical means that A␤ pE3 is present in equivalent or larger amounts than full-length A␤ in senile plaques.…”

Section: Discovery Of Pyroglutamate A␤mentioning

confidence: 99%

Pyroglutamate Amyloid-β (Aβ): A Hatchet Man in Alzheimer Disease

Jawhar

Wirths

Bayer

2011

Journal of Biological Chemistry

195

225

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Pyroglutamate-modified amyloid-␤ (A␤ pE3 ) peptides are gaining considerable attention as potential key participants in the pathology of Alzheimer disease (AD) due to their abundance in AD brain, high aggregation propensity, stability, and cellular toxicity. Transgenic mice that produce high levels of A␤ pE3-42 show severe neuron loss. Recent in vitro and in vivo experiments have proven that the enzyme glutaminyl cyclase catalyzes the formation of A␤ pE3 . In this minireview, we summarize the current knowledge on A␤ pE3 , discussing its discovery, biochemical properties, molecular events determining formation, prevalence in the brains of AD patients, Alzheimer mouse models, and potential as a target for therapy and as a diagnostic marker.When Alois Alzheimer presented the case of his patient Auguste Deter at the Tübingen meeting of the Southwest German Psychiatrists in 1906, he did not attract much attention or stimulate any discussion in the audience. The young doctor likely would not have believed that, 100 years later, the disease that now holds his name would be the most common cause of dementia and a source of a critical medical and economical problem. At this meeting, Alzheimer presented Auguste Deter's symptoms and reported the histopathological features that are now associated with Alzheimer disease (AD) 2 : neuron loss, extracellular amyloid plaques, and intracellular neurofibrillary tangles. For more than 2 decades, the amyloid hypothesis has been the cardinal hypothesis in describing the sequence of AD etiology. The amyloid hypothesis considers amyloid-␤ (A␤) deposition to be the causative event of AD pathology and that neurofibrillary tangles, cell loss, vascular damage, and dementia occur as a consequence of it (1). However, it has been recently suggested that the extracellular formation of A␤ plaques and other AD pathological events are preceded by intraneuronal A␤ accumulation, giving rise to a modified amyloid hypothesis (2).The story of successful discoveries in modern AD research using novel molecular biological tools started with the biochemical analysis of ␤-amyloid-containing blood vessels (congophilic amyloid angiopathy) (3) and amyloid plaques consisting of A␤ (4), which led to the isolation and sequencing of the gene encoding the larger amyloid precursor protein (APP) (5, 6).In vitro and in vivo analyses of amyloid deposits in AD revealed various N-and C-terminal variants (4, 7, 8). Increased C-terminal length of A␤ (from A␤ x-40 to A␤ x-42 ) in AD enhanced aggregation and early deposition and promoted the toxicity of A␤ (9 -11). Recently, A␤ 1-43 has been discussed as a novel toxic peptide in AD (12).Beside A␤ peptides, starting with aspartate as the first amino acid (A␤ 1-x ), several N-terminally truncated and modified A␤ species have been described (4, 13-15). Among A␤ species present in AD plaques, Lewis et al. (16) reported that A␤ 4 -42 is a relatively abundant species in AD, aged control, and vascular dementia patients. Using immunoprecipitation in combination with mass spectrome...

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Section: Discovery Of Pyroglutamate A␤mentioning

confidence: 99%

Pyroglutamate Amyloid-β (Aβ): A Hatchet Man in Alzheimer Disease

Jawhar

Wirths

Bayer

2011

Journal of Biological Chemistry

195

225

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“…Peptide aggregation and the presence of these modifications could potentially confound immunoassay‐based procedures. There have been a number of reports on the use of mass spectrometry (MS) for the analysis of A β peptides 17–32. These studies have generally either focused on structural aspects of A β ‐peptides or the analysis of cell‐derived peptides 23.…”

Section: Reported Concentrations Of Aβ1‐42 In Human Csfmentioning

confidence: 99%

Quantitative analysis of amyloid β peptides in cerebrospinal fluid of Alzheimer's disease patients by immunoaffinity purification and stable isotope dilution liquid chromatography/negative electrospray ionization tandem mass spectrometry

Ackermann²,

Inoue

et al. 2006

Rapid Comm Mass Spectrometry

153

150

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The 40 and 42 amino-acid residue forms of amyloid beta (Abeta(1-40) and Abeta(1-42)) in cerebrospinal fluid (CSF) have been proposed as potential biomarkers of Alzheimer's disease (AD). Quantitative analyses of Abeta peptides in CSF have relied almost exclusively on the use of immunoassay-based assays such as the enzyme-linked immunosorbent assay (ELISA) procedure. However, due to the ability of the Abeta peptides to readily self-aggregate or bind to other proteins and glassware, such analyses are extremely challenging. Analyses are further complicated by the potential of the peptides to undergo post-translational modifications and the possibilities for cross-reaction in the ELISA assays with endogenous components of the CSF. An approach based on liquid chromatography/tandem mass spectrometry (LC/MS/MS) has now been developed which overcomes these methodological issues. The key steps in implementing this new approach involved immunoaffinity purification coupled with the use of [15N]-labeled Abeta peptides as internal standards, a basic LC mobile phase, negative ion electrospray ionization, and a basic solvent for dissolving the peptides and washing the injection needle to prevent carryover of analytes during multiple injections on the LC/MS system. The validated method had limits of quantitation of 44 fmol/mL (200 pg/mL) for Abeta(1-42) and 92 fmol/mL (400 pg/mL) for Abeta(1-40). An excellent correlation was found between the LC/MS/MS assay and an ELISA assay for Abeta(1-42) in human CSF (r2 = 0.915), although less correlation was observed for Abeta(1-40) (r2 = 0.644). Mean CSF Abeta(1-42) concentrations for samples collected 2 weeks apart from a limited number of AD patients provided additional confidence in the reproducibility of the LC/MS/MS assay. Concentrations for duplicate samples from AD patients were slightly higher than most previously reported values (mean 1.06 +/- 0.25 ng/mL; n = 7). Abeta(1-40) concentrations in duplicate samples obtained from AD patients were also reproducible but were found to be slightly lower than most previously reported values (mean 6.36 +/- 3.07 ng/mL; n = 7). Consistent with literature reports, mean Abeta(1-42) concentrations were found to be lower in AD patients compared with the normal subjects (mean 1.49 +/- 0.59 ng/mL; n = 7), whereas there was no difference in Abeta(1-40) concentrations between AD patients and normal subjects (mean 5.88 +/- 3.03 ng/mL; n = 7). The accuracy and precision of the LC/MS assay mean that it will be a useful complement to existing ELISA assays for monitoring therapeutic interventions designed to modulate CSF Abeta(1-42) concentrations in individual AD patients. Moreover, the introduction of stable isotope labeled internal standards offers the potential to achieve a more rigorous account of the influence of methodological effects related to sample collection and processing.

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“…It has been demonstrated that the amyloid‐β‐peptides are neurotoxic 2, 3. The development of amyloid fibrils, which are internal parts of senile plaques, is connected with the concentration and the size of the amyloid‐β‐peptides 4–7…”

Section: Introductionmentioning

confidence: 99%

Interaction between synthetic amyloid‐β‐peptide (1–40) and its aggregation inhibitors studied by electrospray ionization mass spectrometry

2001

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It is generally postulated that amyloid-beta-peptides play a central role in the progressive neurodegeneration observed in Alzheimer's disease. Important pathological properties of these peptides, such as neurotoxicity and resistance to proteolytic degradation, depend on the ability of amyloid-beta-peptides to form beta-sheet structures and/or amyloid fibrils. Amyloid-beta-peptides are known to aggregate spontaneously in vitro with the formation of amyloid fibrils. The intervention on the amyloid-beta-peptides aggregation process can be envisaged as an approach to stopping or slowing the progression of Alzheimer's disease. In the last few years a number of small molecules have been reported to interfere with the in vitro aggregation of amyloid-beta-peptides. Melatonin, a hormone recently found to protect neurons against amyloid-beta-peptide toxicity, interacts with amyloid-beta-peptide (1-40) and amyloid-beta-peptide (1-42) and inhibits the progressive formation of beta-sheet and/or amyloid fibrils. These interactions between melatonin and the amyloid peptides have been demonstrated by circular dichroism (CD) and electron microscopy for amyloid-beta-peptide (1-40) and amyloid-beta-peptide (1-42) and by nuclear magnetic resonance (NMR) spectroscopy for amyloid-beta-peptide (1-40). Our electrospray ionization mass spectrometric (ESI-MS) studies also proved that there is a hydrophobic interaction between amyloid-beta-peptide (1-40) and melatonin and the proteolytic investigations suggested that the interaction took place on the 29-40 amyloid-beta-peptide segment. The wide-ranging application of these results would provide further information and help in biological research.

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On-line high-performance liquid chromatography/mass spectrometric investigation of amyloid-β peptide variants found in Alzheimer's disease

Cited by 12 publications

References 22 publications

Pyroglutamate Amyloid-β (Aβ): A Hatchet Man in Alzheimer Disease

Pyroglutamate Amyloid-β (Aβ): A Hatchet Man in Alzheimer Disease

Quantitative analysis of amyloid β peptides in cerebrospinal fluid of Alzheimer's disease patients by immunoaffinity purification and stable isotope dilution liquid chromatography/negative electrospray ionization tandem mass spectrometry

Interaction between synthetic amyloid‐β‐peptide (1–40) and its aggregation inhibitors studied by electrospray ionization mass spectrometry

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