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P1‐247: CEREBROSPINAL FLUID NEUROFILAMENT LIGHT PROTEIN AS A DIFFERENTIAL DIAGNOSIS BIOMARKER IN NEUROLOGICAL DISEASES: A SYSTEMATIC REVIEW AND METAANALYSIS
Author(s) -
Bridel Claire,
Wieringen Wessel,
Zettenberg Henrik,
Visser Pieter Jelle,
Tijms Betty M.,
Teunissen Charlotte E.
Publication year - 2018
Publication title -
alzheimer's and dementia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.713
H-Index - 118
eISSN - 1552-5279
pISSN - 1552-5260
DOI - 10.1016/j.jalz.2018.06.252
Subject(s) - cerebrospinal fluid , biomarker , medicine , multiple sclerosis , differential diagnosis , dementia , vascular dementia , pathology , gastroenterology , stroke (engine) , disease , immunology , biology , mechanical engineering , biochemistry , engineering
Background:Amyloid-b (Ab) oligomers are crucial neurotoxins in Alzheimer’s disease. While there have been many advances in understanding fibril structure, relatively little is known about oligomer structure and mode of association. We now report on indefinitely stable small oligomers made under low-ionic and low-temperature conditions. Methods: Unlabeled and Cand/or N-labeled Ab40 was expressed inE. coli using a novel expression system reported elsewhere. Chemical shift assignmentwermade using standard triple resonance techniques. Oligomers were also characterized by DLS, TEM and AFM. Dynamic properties of oligomers were assessed by the following experiments: T1/T2 measurements, heteronuclear NOEs, Cleanex, and diffusionNMRexperiments (DOSY). In addition, chemical shift perturbationsweremeasured in the presenceofPr, andpeak broadening was assessed in the presence of Gd. Results:Ab was at 10-200 mM at 5-37 oC, and low ionic strength conditions commonly used for adding Ab oligomers to tissue culture systems. At 5 oC, DLS, TEM and AFM indicated diameter 1⁄4 4-6nm. Chemical shifts in N-HSQC spectra variedwith peptide concentration, either by dilution of concentrated samples or in solutions made freshly at various concentrations. Chemical shift perturbations (CSPs) were most marked in regions surroundingH6,H13 andH14. Similar distributions were found for CSPs induced by Pr, and for line broadening induced byGd.Dynamics experiments indicated avery rapid equilibriumbetween monomer and oligomer. Addition of EDTA or high ionic strength, suppressed CSPs observed by varying peptide concentration, indicating that themonomer-oligomer equilibrium ismetal-ion dependent. Bound metal ions were analyzed using ICP-MS. Dynamics experiments were obtained to calculate order parameters, to test the hypothesis that themonomers andoligomers constitute a second-order, liquid-in-liquid phase transition, dependent onmetal ions.Conclusions: We have characterized small, indefinitely stable Ab oligomers under conditions similar to those commonlyused todissolvepeptide for addition to cell or tissue culture system. Oligomers appear to be present immediately after dissolving peptide. Monomers and oligomers are invery rapid equilibrium.This formof oligomerization is strongly supported by metal ions, and may constitute a second-order liquid-inliquid phase transition. P1-247 CEREBROSPINAL FLUID NEUROFILAMENT LIGHT PROTEIN AS A DIFFERENTIAL DIAGNOSIS BIOMARKER IN NEUROLOGICAL DISEASES: A SYSTEMATIC REVIEWAND METAANALYSIS Claire Bridel, Wessel van Wieringen, Henrik Zettenberg, Pieter Jelle Visser, Betty M. Tijms, Charlotte E. Teunissen and CSF Neurofilament Light Meta-analysis Research Group, VUmc, Amsterdam, Netherlands; VU University Medical Center Amsterdam, Amsterdam, Netherlands; UK Dementia Research Institute, London, United Kingdom; Alzheimer Center andDepartment of Neurology, AmsterdamNeuroscience, VU University Medical Center, Amsterdam, Netherlands; Alzheimer Center & Department of Neurology, Amsterdam Neuroscience, VU University Medical Center, Amsterdam, Netherlands; VU University Medical Center, Amsterdam, Netherlands; Neurochemistry Laboratory and Biobank, Department of Clinical Chemistry, Amsterdam Neuroscience, VU University Medical Center, Amsterdam, Netherlands. Contact e-mail: c. teunissen@vumc.nl