%0 Journal Article %J J Alzheimers Dis %D 2018 %T ABC Transporters Are Key Players in Alzheimer's Disease. %A Pereira, Cátia D %A Martins, Filipa %A Wiltfang, Jens %A da Cruz E Silva, Odete A B %A Rebelo, Sandra %K Alzheimer Disease %K Amyloid beta-Peptides %K Animals %K ATP-Binding Cassette Transporters %K Blood-Brain Barrier %K Humans %X

Human ATP-binding cassette (ABC) transporters mediate a critical function in the cell, namely the transport of molecules across lipid membranes. Associated to their ubiquitous tissue distribution, they are key players in cellular homeostasis but also potential causative or contributing factors for many pathologies, including Alzheimer's disease (AD). In the central nervous system (CNS), numerous ABC transporters are present throughout the brain parenchyma and especially at the blood-brain barrier (BBB). AD is a neurodegenerative disorder mainly characterized by extracellular deposition of amyloid-β (Aβ) peptides and intracellular accumulation of hyperphosphorylated forms of tau protein. Besides being degraded via proteolytic and phagocytic processes mediated by brain parenchymal cells, a major mechanism for eliminating cerebral Aβ is through its transport across the BBB into the peripheral blood. In fact, many AD cases are associated with impaired Aβ clearance. Consistently, several studies have recently uncovered important roles for ABC transporters in AD pathophysiology. Hence, this review focuses on the relevance of ABC transporters in CNS homeostasis by highlighting AD as a strong example of the deleterious consequences that might result from the former's altered expression and/or activity in the brain. The potentiality of human ABC transporters as novel pharmacological targets for both the diagnosis and therapeutics of AD is emphasized.

%B J Alzheimers Dis %V 61 %P 463-485 %8 2018 %G eng %N 2 %1 http://www.ncbi.nlm.nih.gov/pubmed/29171999?dopt=Abstract %R 10.3233/JAD-170639 %0 Journal Article %J J Alzheimers Dis %D 2016 %T Comparison of Different Matrices as Potential Quality Control Samples for Neurochemical Dementia Diagnostics. %A Lelental, Natalia %A Brandner, Sebastian %A Kofanova, Olga %A Blennow, Kaj %A Zetterberg, Henrik %A Andreasson, Ulf %A Engelborghs, Sebastiaan %A Mroczko, Barbara %A Gabryelewicz, Tomasz %A Teunissen, Charlotte %A Mollenhauer, Brit %A Parnetti, Lucilla %A Chiasserini, Davide %A Molinuevo, José Luis %A Perret-Liaudet, Armand %A Verbeek, Marcel M %A Andreasen, Niels %A Brosseron, Frederic %A Bahl, Justyna M C %A Herukka, Sanna-Kaisa %A Hausner, Lucrezia %A Frölich, Lutz %A Labonte, Anne %A Poirier, Judes %A Miller, Anne-Marie %A Zilka, Norbert %A Kovacech, Branislav %A Urbani, Andrea %A Suardi, Silvia %A Oliveira, Catarina %A Baldeiras, Ines %A Dubois, Bruno %A Rot, Uros %A Lehmann, Sylvain %A Skinningsrud, Anders %A Betsou, Fay %A Wiltfang, Jens %A Gkatzima, Olymbia %A Winblad, Bengt %A Buchfelder, Michael %A Kornhuber, Johannes %A Lewczuk, Piotr %K Amyloid beta-Peptides %K Animals %K Anti-Bacterial Agents %K Biomarkers %K Cattle %K Clinical Chemistry Tests %K Dementia %K Humans %K Peptide Fragments %K Quality Control %K Reference Standards %K Serum Albumin, Bovine %K Sodium Azide %K tau Proteins %K Time Factors %K Tissue Preservation %X

BACKGROUND: Assay-vendor independent quality control (QC) samples for neurochemical dementia diagnostics (NDD) biomarkers are so far commercially unavailable. This requires that NDD laboratories prepare their own QC samples, for example by pooling leftover cerebrospinal fluid (CSF) samples.

OBJECTIVE: To prepare and test alternative matrices for QC samples that could facilitate intra- and inter-laboratory QC of the NDD biomarkers.

METHODS: Three matrices were validated in this study: (A) human pooled CSF, (B) Aβ peptides spiked into human prediluted plasma, and (C) Aβ peptides spiked into solution of bovine serum albumin in phosphate-buffered saline. All matrices were tested also after supplementation with an antibacterial agent (sodium azide). We analyzed short- and long-term stability of the biomarkers with ELISA and chemiluminescence (Fujirebio Europe, MSD, IBL International), and performed an inter-laboratory variability study.

RESULTS: NDD biomarkers turned out to be stable in almost all samples stored at the tested conditions for up to 14 days as well as in samples stored deep-frozen (at - 80°C) for up to one year. Sodium azide did not influence biomarker stability. Inter-center variability of the samples sent at room temperature (pooled CSF, freeze-dried CSF, and four artificial matrices) was comparable to the results obtained on deep-frozen samples in other large-scale projects.

CONCLUSION: Our results suggest that it is possible to replace self-made, CSF-based QC samples with large-scale volumes of QC materials prepared with artificial peptides and matrices. This would greatly facilitate intra- and inter-laboratory QC schedules for NDD measurements.

%B J Alzheimers Dis %V 52 %P 51-64 %8 2016 03 01 %G eng %N 1 %1 http://www.ncbi.nlm.nih.gov/pubmed/26967210?dopt=Abstract %R 10.3233/JAD-150883 %0 Journal Article %J J Alzheimers Dis %D 2016 %T N-truncated Aβ2-X starting with position two in sporadic Alzheimer's disease cases and two Alzheimer mouse models. %A Savastano, Adriana %A Klafki, Hans %A Haußmann, Ute %A Oberstein, Timo Jan %A Muller, Petr %A Wirths, Oliver %A Wiltfang, Jens %A Bayer, Thomas A %K Aged %K Aged, 80 and over %K Alzheimer Disease %K Amyloid beta-Peptides %K Animals %K Blotting, Western %K Brain %K Cerebral Amyloid Angiopathy %K Disease Models, Animal %K Female %K Humans %K Male %K Mice %K Mice, Transgenic %K Plaque, Amyloid %X

According to the modified amyloid hypothesis, the key event in the pathogenesis of Alzheimer's disease (AD) is the deposition of neurotoxic amyloid β-peptides (Aβs) in plaques and cerebral blood vessels. Additionally to full-length peptides, a great diversity of N-truncated Aβ variants is derived from the larger amyloid-β protein precursor (AβPP). Vast evidence suggests that Aβx-42 isoforms play an important role in triggering neurodegeneration due to their high abundance, amyloidogenic propensity and toxicity. Although N-truncated Aβ peptides and Aβx-42 species appear to be the crucial players in AD etiology, the Aβ2-X isoforms did not receive much attention yet. The present study is the first to show immunohistochemical evidence of Aβ2-X in cases of AD and its distribution in AβPP/PS1KI and 5XFAD transgenic mouse models using a novel antibody pAB77 that has been developed using Aβ2-14 as antigen. Positive plaques and congophilic amyloid angiopathy (CAA) were observed in AD cases and in both mouse models. While in AD cases, abundant CAA and less pronounced plaque pathology was evident, the two mouse models showed predominantly extracellular Aβ deposits and minor CAA staining. Western blotting and a capillary isoelectric focusing immunoassay demonstrated the high specificity of the antibody pAb77 against Aβ-variants starting with the N-terminal Alanine-2.

%B J Alzheimers Dis %V 49 %P 101-10 %8 2016 %G eng %N 1 %1 http://www.ncbi.nlm.nih.gov/pubmed/26529393?dopt=Abstract %R 10.3233/JAD-150394