Methods for Analysis of Amyloid-β AggregatesBruggink, Kim A. ; Müller, Mareike ; Kuiperij, H. Bea ; Verbeek, Marcel M.
doi: 10.3233/JAD-2011-111421pmid: 22156047
Amyloid-β protein (Aβ) accumulation is one of the major hallmarks of Alzheimer's disease and plays a crucial role in its pathogenesis. Aβ aggregates into fibrils, but rather than these end-products of the aggregation process, intermediate species, referred to as oligomers, have been identified as the most neurotoxic Aβ aggregates. To characterize the different Aβ species and to study the aggregation process, a wide range of techniques has been applied over the past years. These techniques aim to visualize the different Aβ species and study their structure, to separate them, and to quantify the aggregated Aβ forms by immunology-based methods. In this review, we provide an overview and discussion of the most important techniques used for these aims. Often a combination of techniques will be appropriate to obtain the most optimal information.
Methods for Analysis of Amyloid-β AggregatesBruggink, Kim A.; Müller, Mareike; Kuiperij, H. Bea; Verbeek, Marcel M.
doi: 10.3233/jad-2011-111421pmid: 22156047
Amyloid-β protein (Aβ) accumulation is one of the major hallmarks of Alzheimer's disease and plays a crucial role in its pathogenesis. Aβ aggregates into fibrils, but rather than these end-products of the aggregation process, intermediate species, referred to as oligomers, have been identified as the most neurotoxic Aβ aggregates. To characterize the different Aβ species and to study the aggregation process, a wide range of techniques has been applied over the past years. These techniques aim to visualize the different Aβ species and study their structure, to separate them, and to quantify the aggregated Aβ forms by immunology-based methods. In this review, we provide an overview and discussion of the most important techniques used for these aims. Often a combination of techniques will be appropriate to obtain the most optimal information.
The Progranulin (GRN) Cys157LysfsX97 Mutation is Associated with Nonfluent Variant of Primary Progressive Aphasia Clinical PhenotypeCaso, Francesca ; Villa, Chiara ; Fenoglio, Chiara ; Santangelo, Roberto ; Agosta, Federica ; Coppi, Elisabetta ; Falautano, Monica ; Comi, Giancarlo ; Filippi, Massimo ; Scarpini, Elio ; Magnani, Giuseppe ; Galimberti, Daniela
doi: 10.3233/JAD-2011-111544pmid: 22072213
The progranulin gene (GRN) g.10325_10331delCTGCTGT (relative to nt1 in NG_007886.1), alias Cys157LysfsX97, has been so far reported only once in a patient with frontotemporal dementia. Here, we describe a 63-year old patient carrying the same mutation, presenting with a 3-year history of language disorder, and diagnosed clinically with nonfluent variant of primary progressive aphasia according to current criteria. This patient's description expands the spectrum of clinical presentations of frontotemporal lobar degeneration caused by the GRN Cys157LysfsX97 mutation.
Impaired Glutamatergic and GABAergic Function at Early Age in AβPPswe-PS1dE9 Mice: Implications for Alzheimer's DiseaseTiwari, Vivek; Patel, Anant B.
doi: 10.3233/jad-2011-111502pmid: 22112551
Preclinical diagnosis of Alzheimer's disease is a major challenge. The present study evaluates glutamatergic and GABAergic neurotransmitter energetics at the age of 6 months in AβPPswe-PS1dE9 mouse model of Alzheimer's disease by using 1H-[13C]-NMR spectroscopy together with infusion of [1,6-13C2]glucose. NMR analysis suggested no significant derangement in neurochemical profile in AβPPswe-PS1dE9 mice. However, decrease in labeling of glutamate-C4, GABA-C2 and glutamine-C4 at early infusion-time together with no change in labeling at steady state from [1,6-13C2]glucose indicates an impaired glutamatergic and GABAergic glucose oxidation and neurotransmitter cycle in AβPPswe-PS1dE9 mice. These findings may have implication in preclinical diagnosis of Alzheimer's disease.
Impaired Glutamatergic and GABAergic Function at Early Age in AβPPswe-PS1dE9 Mice: Implications for Alzheimer's DiseaseTiwari, Vivek ; Patel, Anant B.
doi: 10.3233/JAD-2011-111502pmid: 22112551
Preclinical diagnosis of Alzheimer's disease is a major challenge. The present study evaluates glutamatergic and GABAergic neurotransmitter energetics at the age of 6 months in AβPPswe-PS1dE9 mouse model of Alzheimer's disease by using 1 H-( 13 C)-NMR spectroscopy together with infusion of (1,6- 13 C 2 )glucose. NMR analysis suggested no significant derangement in neurochemical profile in AβPPswe-PS1dE9 mice. However, decrease in labeling of glutamate-C4, GABA-C2 and glutamine-C4 at early infusion-time together with no change in labeling at steady state from (1,6- 13 C 2 )glucose indicates an impaired glutamatergic and GABAergic glucose oxidation and neurotransmitter cycle in AβPPswe-PS1dE9 mice. These findings may have implication in preclinical diagnosis of Alzheimer's disease.
The Dying of the Light: Mitochondrial Failure in Alzheimer's DiseaseYoung-Collier, Kisha J.; McArdle, Michael; Bennett, James P.
doi: 10.3233/jad-2011-111487pmid: 22057028
Impaired brain energy production, reflected by reduced cortical glucose metabolism seen on 2-FDG PET scans, has emerged as a robust biomarker of mild cognitive impairment (MCI). Progression from MCI to Alzheimer's disease (AD) shows further decline of cortical 2-FDG uptake, implying worsening bioenergetics. We characterized respiration, respiratory protein levels, and gene expressions for mitochondrial DNA (mtDNA), mitochondrial biogenesis, and antioxidative signaling in preparations from postmortem AD and control frontal cortex. Mitochondrial respiration was maintained in frozen brain mitochondria and reduced by approximately two-thirds in AD due to loss of mitochondrial mass. Levels of most respiratory proteins were preserved, but expressions of gene families for mtDNA, mitobiogenesis, and mitochondrial/cytosolic antioxidant enzymes were reduced in AD cortex. None of these changes in AD were related to elevated levels of amyoid-β1-42 peptide. For unclear reasons, mitochondrial biogenesis is suppressed in AD frontal cortex, leading to reduced mitochondrial mass and impaired mitochondrial respiratory capacity. Downregulation of antioxidant proteins further threatens neuronal function. Altering progression of AD appears to require both correction of impaired mitobiogenesis and restoration of antioxidant protection.
The Dying of the Light: Mitochondrial Failure in Alzheimer's DiseaseYoung-Collier, Kisha J. ; McArdle, Michael ; Bennett, James P.
doi: 10.3233/JAD-2011-111487pmid: 22057028
Impaired brain energy production, reflected by reduced cortical glucose metabolism seen on 2-FDG PET scans, has emerged as a robust biomarker of mild cognitive impairment (MCI). Progression from MCI to Alzheimer's disease (AD) shows further decline of cortical 2-FDG uptake, implying worsening bioenergetics. We characterized respiration, respiratory protein levels, and gene expressions for mitochondrial DNA (mtDNA), mitochondrial biogenesis, and antioxidative signaling in preparations from postmortem AD and control frontal cortex. Mitochondrial respiration was maintained in frozen brain mitochondria and reduced by approximately two-thirds in AD due to loss of mitochondrial mass. Levels of most respiratory proteins were preserved, but expressions of gene families for mtDNA, mitobiogenesis, and mitochondrial/cytosolic antioxidant enzymes were reduced in AD cortex. None of these changes in AD were related to elevated levels of amyoid-β 1-42 peptide. For unclear reasons, mitochondrial biogenesis is suppressed in AD frontal cortex, leading to reduced mitochondrial mass and impaired mitochondrial respiratory capacity. Downregulation of antioxidant proteins further threatens neuronal function. Altering progression of AD appears to require both correction of impaired mitobiogenesis and restoration of antioxidant protection.
Detection of Peri-Synaptic Amyloid-β Pyroglutamate Aggregates in Early Stages of Alzheimer's Disease and in AβPP Transgenic Mice Using a Novel Monoclonal AntibodyMandler, Markus ; Rockenstein, Edward ; Ubhi, Kiren ; Hansen, Lawrence ; Adame, Anthony ; Michael, Sarah ; Galasko, Douglas ; Santic, Radmila ; Mattner, Frank ; Masliah, Eliezer
doi: 10.3233/JAD-2011-111208pmid: 22064070
The neurodegenerative pathology in patients with Alzheimer's disease (AD) has been associated with the progressive accumulation of aggregated and post-translationally modified amyloid-β (Aβ) species. Among them, recent studies indicate that the pyroglutamate modification of Aβ (pE(3)Aβ) catalyzed by glutaminyl cyclase might play an important role in the pathogenesis of AD. Although the effects of the pyroglutamate modification on Aβ aggregation and toxicity have been investigated, less is known about the distribution of pE(3)Aβ across the spectrum of AD and in the brains of amyloid-β protein precursor (AβPP) transgenic (tg) animals. For this purpose, we generated a novel monoclonal antibody (denominated D129) that specifically recognizes pE(3)Aβ and characterized the patterns of distribution in the postmortem brain samples from AD patients divided by disease stage (Braak stage) and in AβPP tg mice. We found that in early stages of AD and young AβPP tg mice pE(3)Aβ was found in discrete linear and granular aggregates in the neuropil that co-localized with the pre-synaptic protein synaptophysin and was in close opposition to dendrites labeled with MAP2. In later stages of AD and in older AβPP tg mice, pE(3)Aβ was abundant in diffuse and mature plaques. In conclusion, this study suggests that peri-synaptic accumulation of pE(3)Aβ might contribute to early cognitive dysfunction in AD.