Comparison of size distribution and (Pro249-Ser258) epitope exposure in in vitro and in vivo derived Tau fibrils

BMC Molecular and Cell Biology

article

Marreiro, André¹  Apetri, Adrian³  Schoofs, Liliane²  Mercken, Marc H.¹  Van Kolen, Kristof¹  Sousa, Cristiano¹  Temmerman, Liesbet²  Vasconcelos, Bruno¹  Crespo-Rodriguez, Rosa³  van Weering, Jan R. T.⁵  Van Dam, Debby⁶  De Deyn, Peter P.⁶ 

[1] Neuroscience department;Animal Physiology and Neurobiology;Janssen Prevention Center;Neurochemistry Lab, Clinical Chemistry department of the Amsterdam UMC;Department of Clinical Genetics, Center for Neurogenomics and Cognitive Research (CNCR);Laboratory of Neurochemistry and Behavior, University of Antwerp;Department of Neurology and Alzheimer Center Groningen, University Medical Center Groningen (UMCG);Department of Neurology and Memory Clinic, Hospital Network Antwerp (ZNA) Middelheim and Hoge Beuken;Institute Born-Bunge, University of Antwerp, Universiteitsplein 1

关键词: Alzheimer’s disease;    Tau;    Tau aggregation;    Aggregation;    Seeding;   

DOI  :  10.1186/s12860-020-00320-y

学科分类：内科医学

来源: Colegio Oficial de Psicologos

【 摘 要 】

Although several studies demonstrate prion-like properties of Tau fibrils, the effect of size in the seeding capacity of these aggregates is not fully understood. The aim of this study is to characterize Tau seeds by their size and seeding capacity. Tau aggregates were isolated from postmortem AD brain tissue and separated from low molecular weight species by sucrose gradient ultracentrifugation. Biochemical characterization of the different fractions was done by non-reducing Western blotting and aggregate-specific immuno-assays using in house developed anti-Tau monoclonal antibodies, including PT76 which binds to an epitope close to the microtubule-binding domain and, hence, also to K18. Seeding efficiency was then assessed in HEK293 cells expressing K18 FRET sensors. We observed that upon sonication of Tau aggregates different size-distributed tau aggregates are obtained. In biochemical assays, these forms show higher signals than the non-sonicated material in some aggregation-specific Tau assays. This could be explained by an increased epitope exposure of the smaller aggregates created by the sonication. By analyzing human brain derived and recombinant (K18) Tau aggregates in a cellular FRET assay, it was observed that, in the absence of transfection reagent, sonicated aggregates showed higher aggregation induction. Preparations also showed altered profiles on native PAGE upon sonication and we could further separate different aggregate species based on their molecular weight via sucrose gradients. This study further elucidates the molecular properties regarding relative aggregate size and seeding efficiency of sonicated vs. non-sonicated high molecular weight Tau species. This information will provide a better knowledge on how sonication, a commonly used technique in the field of study of Tau aggregation, impacts the aggregates. In addition, the description of PT76-based aggregation specific assay is a valuable tool to quantify K18 and human AD Tau fibrils.

【 授权许可】

CC BY|CC0