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Qasrawi D, Al-Ghabkari A, Khan RM, Petrotchenko EV, Montero-Odasso M, Borchers CH. A Simplified Proteomics LC-MRM-MS Assay for Determination of apoE Genotypes in Plasma Samples. J Proteome Res 2024; 23:1144-1149. [PMID: 38412507 PMCID: PMC11002930 DOI: 10.1021/acs.jproteome.3c00557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 02/12/2024] [Accepted: 02/12/2024] [Indexed: 02/29/2024]
Abstract
Apolipoprotein E (apoE), a polymorphic plasma protein, plays a pivotal role in lipid transportation. The human apoE gene possesses three major alleles (ε2, ε3, and ε4), which differ by single amino acid (cysteine to arginine) substitutions. The ε4 allele represents the primary genetic risk factor for Alzheimer's disease (AD), whereas the ε2 allele protects against the disease. Knowledge of a patient's apoE genotype has high diagnostic value. A recent study has introduced an LC-MRM-MS-based proteomic approach for apoE isoform genotyping using stable isotope-labeled peptide internal standards (SIS). Here, our goal was to develop a simplified LC-MRM-MS assay for identifying apoE genotypes in plasma samples, eliminating the need for the use of SIS peptides. To determine the apoE genotypes, we monitored the chromatographic peak area ratios of isoform-specific peptides relative to a peptide that is common to all apoE isoforms. The assay results correlated well with the standard TaqMan allelic discrimination assay, and we observed a concordance between the two methods for all but three out of 172 samples. DNA sequencing of these three samples has confirmed that the results of the LC-MRM-MS method were correct. Thus, our simplified UPLC-MRM-MS assay is a feasible and reliable method for identifying apoE genotypes without using SIS internal standard peptides. The approach can be seamlessly incorporated into existing quantitative proteomics assays and kits, providing additional valuable apoE genotype information. The principle of using signal ratios of the protein isoform-specific peptides to the peptide common for all of the protein isoforms has the potential to be used for protein isoform determination in general.
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Affiliation(s)
- Deema
O. Qasrawi
- Segal
Cancer Proteomics Centre, Lady Davis Institute for Medical Research,
Jewish General Hospital, McGill University, Montreal, Québec H3T 1E2, Canada
| | - Abdulhameed Al-Ghabkari
- Rosalind
and Morris Goodman Cancer Institute, McGill
University, Montreal, Québec H3A 1A3, Canada
| | - Rania M. Khan
- Segal
Cancer Proteomics Centre, Lady Davis Institute for Medical Research,
Jewish General Hospital, McGill University, Montreal, Québec H3T 1E2, Canada
| | - Evgeniy V. Petrotchenko
- Segal
Cancer Proteomics Centre, Lady Davis Institute for Medical Research,
Jewish General Hospital, McGill University, Montreal, Québec H3T 1E2, Canada
| | - Manuel Montero-Odasso
- Gait
and Brain Lab, Parkwood Institute, Lawson
Health Research Institute, London, Ontario N6C 0A7, Canada
- Department
of Medicine, Division of Geriatric Medicine, Schulich School of Medicine
& Dentistry, University of Western Ontario, London, Ontario N6A 5C1, Canada
- Department
of Epidemiology and Biostatistics, Schulich School of Medicine &
Dentistry, University of Western Ontario, London, Ontario N6A 5C1, Canada
| | - Christoph H. Borchers
- Segal
Cancer Proteomics Centre, Lady Davis Institute for Medical Research,
Jewish General Hospital, McGill University, Montreal, Québec H3T 1E2, Canada
- Segal
Cancer
Centre, Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, Québec H3T 1E2, Canada
- Division
of Experimental Medicine, McGill University, Montreal, Québec H4A 3J1, Canada
- Gerald
Bronfman Department of Oncology, Lady Davis Institute for Medical
Research, Jewish General Hospital, Montreal, Québec H3T 1E2, Canada
- Department
of Pathology, McGill University, Montreal, Québec H3A 2B4, Canada
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Gobom J, Brinkmalm A, Brinkmalm G, Blennow K, Zetterberg H. Alzheimer's Disease Biomarker Analysis Using Targeted Mass Spectrometry. Mol Cell Proteomics 2024; 23:100721. [PMID: 38246483 PMCID: PMC10926085 DOI: 10.1016/j.mcpro.2024.100721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Revised: 12/30/2023] [Accepted: 01/04/2024] [Indexed: 01/23/2024] Open
Abstract
Alzheimer's disease (AD) is characterized by several neuropathological changes, mainly extracellular amyloid aggregates (plaques), intraneuronal inclusions of phosphorylated tau (tangles), as well as neuronal and synaptic degeneration, accompanied by tissue reactions to these processes (astrocytosis and microglial activation) that precede neuronal network disturbances in the symptomatic phase of the disease. A number of biomarkers for these brain tissue changes have been developed, mainly using immunoassays. In this review, we discuss how targeted mass spectrometry (TMS) can be used to validate and further characterize classes of biomarkers reflecting different AD pathologies, such as tau- and amyloid-beta pathologies, synaptic dysfunction, lysosomal dysregulation, and axonal damage, and the prospect of using TMS to measure these proteins in clinical research and diagnosis. TMS advantages and disadvantages in relation to immunoassays are discussed, and complementary aspects of the technologies are discussed.
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Affiliation(s)
- Johan Gobom
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden; Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden.
| | - Ann Brinkmalm
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden; Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden
| | - Gunnar Brinkmalm
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden
| | - Kaj Blennow
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden; Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden
| | - Henrik Zetterberg
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden; Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden; Department of Neurodegenerative Disease, UCL Institute of Neurology, London, UK; UK Dementia Research Institute at UCL, London, UK; Hong Kong Center for Neurodegenerative Diseases, Clear Water Bay, Hong Kong, China; Wisconsin Alzheimer's Disease Research Center, University of Wisconsin School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, USA.
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Li H, Ren J, Li Y, Wu Q, Wei J. Oxidative stress: The nexus of obesity and cognitive dysfunction in diabetes. Front Endocrinol (Lausanne) 2023; 14:1134025. [PMID: 37077347 PMCID: PMC10107409 DOI: 10.3389/fendo.2023.1134025] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Accepted: 03/02/2023] [Indexed: 04/05/2023] Open
Abstract
Obesity has been associated with oxidative stress. Obese patients are at increased risk for diabetic cognitive dysfunction, indicating a pathological link between obesity, oxidative stress, and diabetic cognitive dysfunction. Obesity can induce the biological process of oxidative stress by disrupting the adipose microenvironment (adipocytes, macrophages), mediating low-grade chronic inflammation, and mitochondrial dysfunction (mitochondrial division, fusion). Furthermore, oxidative stress can be implicated in insulin resistance, inflammation in neural tissues, and lipid metabolism disorders, affecting cognitive dysfunction in diabetics.
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Affiliation(s)
- Huimin Li
- Guang’anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Jing Ren
- Guang’anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
- Graduate School of Beijing University of Chinese Medicine, Beijing, China
| | - Yusi Li
- Guang’anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Qian Wu
- Guang’anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Junping Wei
- Guang’anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
- *Correspondence: Junping Wei,
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Maus A, Figdore D, Milosevic D, Algeciras-Schimnich A, Bornhorst J. Comparison of intact protein and digested peptide techniques for high throughput proteotyping of ApoE. Clin Proteomics 2022; 19:42. [PMID: 36380282 PMCID: PMC9664673 DOI: 10.1186/s12014-022-09379-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Accepted: 10/11/2022] [Indexed: 11/16/2022] Open
Abstract
Introduction Apolipoprotein E (ApoE) genotyping has been shown to have diagnostic value in the evaluation of cardiovascular diseases and neurodegenerative disorders such as Alzheimer’s disease. Although genetic testing is well established for this application, liquid chromatography-mass spectrometry (LC–MS) has the potential to provide a high throughput, low-cost alternative for ApoE evaluation. Methods Serum samples were analyzed by peptide, intact protein, and genomic techniques. For peptide analysis, samples were digested with trypsin followed by liquid chromatography-tandem mass spectrometry analysis (LC–MS/MS) using a high-throughput multichannel LC system coupled to a Sciex 7500 mass spectrometer. For intact protein analysis, ApoE was immuno-purified using a monoclonal antibody immobilized on magnetic beads followed by high-resolution LC–MS analysis using an Exploris 480. DNA was extracted and evaluated using Sanger sequencing as a reference method. Results and discussion The peptide measurement method produced one discrepant result when compared to genomic sequencing (out of 38 sequenced samples), whereas the intact protein analysis followed by deconvolution resulted in two discrepant results and when the intact protein data was processed with chromatographic integration there were three discrepant results. Therefore, the intact protein method proved slightly less accurate, required longer analysis time, and is substantially more costly, while providing only a 30 min improvement in sample preparation time. Conclusions With current MS technology clinical laboratories appear to be better served to utilize trypsin digest sample preparation and LC–MS/MS as opposed to high-resolution LC–MS intact protein analysis techniques for evaluation of ApoE proteotype. Peptide analysis methods are capable of producing accurate results with high throughput and minimal cost. Supplementary Information The online version contains supplementary material available at 10.1186/s12014-022-09379-5.
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Giannisis A, Al-Grety A, Carlsson H, Patra K, Twohig D, Sando SB, Lauridsen C, Berge G, Grøntvedt GR, Bråthen G, White LR, Kultima K, Nielsen HM. Plasma apolipoprotein E levels in longitudinally followed patients with mild cognitive impairment and Alzheimer’s disease. Alzheimers Res Ther 2022; 14:115. [PMID: 36002891 PMCID: PMC9400269 DOI: 10.1186/s13195-022-01058-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Accepted: 07/29/2022] [Indexed: 11/10/2022]
Abstract
Abstract
Background
Low levels of plasma apolipoprotein E (apoE) and presence of the APOE ε4 allele are associated with an increased risk of Alzheimer’s disease (AD). Although the increased risk of AD in APOE ε4-carriers is well-established, the protein levels have received limited attention.
Methods
We here report the total plasma apoE and apoE isoform levels at baseline from a longitudinally (24 months) followed cohort including controls (n = 39), patients with stable amnestic mild cognitive impairment during 24 months follow up (MCI-MCI, n = 30), patients with amnestic MCI (aMCI) that during follow-up were clinically diagnosed with AD with dementia (ADD) (MCI-ADD, n = 28), and patients with AD with dementia (ADD) at baseline (ADD, n = 28). We furthermore assessed associations between plasma apoE levels with cerebrospinal fluid (CSF) AD biomarkers and α-synuclein, as well as both CSF and plasma neurofilament light chain (NfL), YKL-40 and kallikrein 6.
Results
Irrespective of clinical diagnosis, the highest versus the lowest apoE levels were found in APOE ε2/ε3 versus APOE ε4/ε4 subjects, with the most prominent differences exhibited in females. Total plasma apoE levels were 32% and 21% higher in the controls versus MCI-ADD and ADD patients, respectively. Interestingly, MCI-ADD patients exhibited a 30% reduction in plasma apoE compared to MCI-MCI patients. This decrease appeared to be associated with brain amyloid-β (Aβ42) pathology regardless of disease status as assessed using the Amyloid, Tau, and Neurodegeneration (A/T/N) classification. In addition to the association between low plasma apoE and low levels of CSF Aβ42, lower apoE levels were also related to higher levels of CSF total tau (t-tau) and tau phosphorylated at Threonine 181 residue (p-tau) and NfL as well as a worse performance on the mini-mental-state-examination. In MCI-ADD patients, low levels of plasma apoE were associated with higher levels of CSF α-synuclein and kallikrein 6. No significant correlations between plasma apoE and the astrocytic inflammatory marker YKL40 were observed.
Conclusions
Our results demonstrate important associations between low plasma apoE levels, Aβ pathology, and progression from aMCI to a clinical ADD diagnosis.
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