Dataset Information

Impact of Amyloid-β on Platelet Mitochondrial Function and Platelet-Mediated Amyloid Aggregation in Alzheimer's Disease.

ABSTRACT: Alzheimer's disease (AD) is characterized by an accumulation of amyloid β (Aβ) peptides in the brain and mitochondrial dysfunction. Platelet activation is enhanced in AD and platelets contribute to AD pathology by their ability to facilitate soluble Aβ to form Aβ aggregates. Thus, anti-platelet therapy reduces the formation of cerebral amyloid angiopathy in AD transgenic mice. Platelet mitochondrial dysfunction plays a regulatory role in thrombotic response, but its significance in AD is unknown and explored herein. The effects of Aβ-mediated mitochondrial dysfunction in platelets were investigated in vitro. Aβ40 stimulation of human platelets led to elevated reactive oxygen species (ROS) and superoxide production, while reduced mitochondrial membrane potential and oxygen consumption rate. Enhanced mitochondrial dysfunction triggered platelet-mediated Aβ40 aggregate formation through GPVI-mediated ROS production, leading to enhanced integrin αIIbβ3 activation during synergistic stimulation from ADP and Aβ40. Aβ40 aggregate formation of human and murine (APP23) platelets were comparable to controls and could be reduced by the antioxidant vitamin C. Mitochondrial dysfunction contributes to platelet-mediated Aβ aggregate formation and might be a promising target to limit platelet activation exaggerated pathological manifestations in AD.

SUBMITTER: Donner L

PROVIDER: S-EPMC8431787 | biostudies-literature | 2021 Sep

REPOSITORIES: biostudies-literature

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Impact of Amyloid-β on Platelet Mitochondrial Function and Platelet-Mediated Amyloid Aggregation in Alzheimer's Disease.

Donner Lili L Feige Tobias T Freiburg Carolin C Toska Laura Mara LM Reichert Andreas S AS Chatterjee Madhumita M Elvers Margitta M

International journal of molecular sciences 20210906 17

<h4>Background</h4>Alzheimer's disease (AD) is characterized by an accumulation of amyloid β (Aβ) peptides in the brain and mitochondrial dysfunction. Platelet activation is enhanced in AD and platelets contribute to AD pathology by their ability to facilitate soluble Aβ to form Aβ aggregates. Thus, anti-platelet therapy reduces the formation of cerebral amyloid angiopathy in AD transgenic mice. Platelet mitochondrial dysfunction plays a regulatory role in thrombotic response, but its significan ...[more]

PMID: 34502546

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Project description:BackgroundImpaired kidney function has a potential confounding effect on blood biomarker levels, including biomarkers for Alzheimer's disease (AD). Given the imminent use of certain blood biomarkers in the routine diagnostic work-up of patients with suspected AD, knowledge on the potential impact of comorbidities on the utility of blood biomarkers is important. We aimed to evaluate the association between kidney function, assessed through estimated glomerular filtration rate (eGFR) calculated from plasma creatinine and AD blood biomarkers, as well as their influence over predicting Aβ-positivity.MethodsWe included 242 participants from the Translational Biomarkers in Aging and Dementia (TRIAD) cohort, comprising cognitively unimpaired individuals (CU; n = 124), mild cognitive impairment (MCI; n = 58), AD dementia (n = 34), and non-AD dementia (n = 26) patients all characterized by [18F] AZD-4694. Plasma samples were analyzed for Aβ42, Aβ40, glial fibrillary acidic protein (GFAP), neurofilament light chain (NfL), tau phosphorylated at threonine 181 (p-tau181), 217 (p-tau217), 231 (p-tau231) and N-terminal containing tau fragments (NTA-tau) using Simoa technology. Kidney function was assessed by eGFR in mL/min/1.73 m2, based on plasma creatinine levels, age, and sex. Participants were also stratified according to their eGFR-indexed stages of chronic kidney disease (CKD). We evaluated the association between eGFR and blood biomarker levels with linear models and assessed whether eGFR provided added predictive value to determine Aβ-positivity with logistic regression models.ResultsBiomarker concentrations were highest in individuals with CKD stage 3, followed by stages 2 and 1, but differences were only significant for NfL, Aβ42, and Aβ40 (not Aβ42/Aβ40). All investigated biomarkers showed significant associations with eGFR except plasma NTA-tau, with stronger relationships observed for Aβ40 and NfL. However, after adjusting for either age, sex or Aβ-PET SUVr, the association with eGFR was no longer significant for all biomarkers except Aβ40, Aβ42, NfL, and GFAP. When evaluating whether accounting for kidney function could lead to improved prediction of Aβ-positivity, we observed no improvements in model fit (Akaike Information Criterion, AIC) or in discriminative performance (AUC) by adding eGFR to a base model including each plasma biomarker, age, and sex. While covariates like age and sex improved model fit, eGFR contributed minimally, and there were no significant differences in clinical discrimination based on AUC values.ConclusionsWe found that kidney function seems to be associated with AD blood biomarker concentrations. However, these associations did not remain significant after adjusting for age and sex, except for Aβ40, Aβ42, NfL, and GFAP. While covariates such as age and sex improved prediction of Aβ-positivity, including eGFR in the models did not lead to improved prediction for any biomarker. Our findings indicate that renal function, within the normal to mild impairment range, does not seem to have a clinically relevant impact when using highly accurate blood biomarkers, such as p-tau217, in a biomarker-supported diagnosis.

Project description:BackgroundPesticide residues have contaminated our environment and nutrition over the last century. Although these compounds are present at very low concentrations, their long-term effects on human health is of concern. The link between pesticide residues and Alzheimer's disease is not clear and difficult to establish. To date, no in vivo experiments have yet modeled the impact of this chronic contamination on neurodegenerative disorders.ObjectivesWe investigated the impact of fungicide residues on the pathological markers of Alzheimer's disease in a transgenic mouse model.MethodsTransgenic (J20, hAPPSw/Ind) mice were chronically exposed to a cocktail of residues of cyprodinil, mepanipyrim, and pyrimethanil at 0.1μg/L in their drinking water for 9 months. We assessed the effects of fungicide residues on the pathological markers of the disease including Aβ aggregates, neuroinflammation, and neuronal loss. Then, we studied the dynamics of Aβ aggregation in vivo via a longitudinal study using two-photon microscopy. Finally, we investigated the molecular mechanisms involved in the production and clearance of Aβ peptides.ResultsWe found that a chronic exposure to three fungicide residues exacerbated aggregation, microgliosis, and neuronal loss. These fungicides also increased vascular amyloid aggregates reminiscent of cerebral amyloid angiopathy between 6 and 9 months of treatment. The mechanism of action revealed that fungicides promoted Aβ peptide fibril formation in vitro and involved an in vivo overexpression of the levels of the β-secretase-cleaving enzyme (BACE1) combined with impairment of Aβ clearance through neprylisin (NEP).ConclusionsChronic exposure of the J20 mouse model of Alzheimer's disease to a cocktail of fungicides, at the regulatory concentration allowed in tap water (0.1μg/L), strengthened the preexisting pathological markers: neuroinflammation, Aβ aggregation, and APP β-processing. We hypothesize prevention strategies toward pesticide long-term exposure may be an alternative to counterbalance the lack of treatment and to slow down the worldwide Alzheimer's epidemic. https://doi.org/10.1289/EHP5550.

Dataset Information

Impact of Amyloid-β on Platelet Mitochondrial Function and Platelet-Mediated Amyloid Aggregation in Alzheimer's Disease.

Publications

Impact of Amyloid-β on Platelet Mitochondrial Function and Platelet-Mediated Amyloid Aggregation in Alzheimer's Disease.

Similar Datasets

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