title: Development and assessment of sensitive immuno-PCR assays for the quantification of cerebrospinal fluid three- and four-repeat tau isoforms in tauopathies.
abstract: Characteristic tau isoform composition of the insoluble fibrillar tau inclusions define tauopathies, including Alzheimer's disease (AD), progressive supranuclear palsy (PSP) and frontotemporal dementia with parkinsonism linked to chromosome 17/frontotemporal lobar degeneration-tau (FTDP-17/FTLD-tau). Exon 10 splicing mutations in the tau gene, MAPT, in familial FTDP-17 cause elevation of tau isoforms with four microtubule-binding repeat domains (4R-tau) compared to those with three repeats (3R-tau). On the basis of two well-characterised monoclonal antibodies against 3R- and 4R-tau, we developed novel, sensitive immuno-PCR assays for measuring the trace amounts of these isoforms in CSF. This was with the aim of assessing if CSF tau isoform changes reflect the pathological changes in tau isoform homeostasis in the degenerative brain and if these would be relevant for differential clinical diagnosis. Initial analysis of clinical CSF samples of PSP (n = 46), corticobasal syndrome (CBS; n = 22), AD (n = 11), Parkinson's disease with dementia (PDD; n = 16) and 35 controls revealed selective decreases of immunoreactive 4R-tau in CSF of PSP and AD patients compared with controls, and lower 4R-tau levels in AD compared with PDD. These decreases could be related to the disease-specific conformational masking of the RD4-binding epitope because of abnormal folding and/or aggregation of the 4R-tau isoforms in tauopathies or increased sequestration of the 4R-tau isoforms in brain tau pathology.
authors.affiliation: Reta Lila Weston Institute, UCL Institute of Neurology, London, UK.
authors.forename: Connie
authors.initials: C
authors.lastname: Luk
authors.forename: Yaroslau
authors.initials: Y
authors.lastname: Compta
authors.forename: Nadia
authors.initials: N
authors.lastname: Magdalinou
authors.forename: Maria José
authors.initials: MJ
authors.lastname: Martí
authors.forename: Geshanthi
authors.initials: G
authors.lastname: Hondhamuni
authors.forename: Henrik
authors.initials: H
authors.lastname: Zetterberg
authors.forename: Kaj
authors.initials: K
authors.lastname: Blennow
authors.forename: Radu
authors.initials: R
authors.lastname: Constantinescu
authors.forename: Yolande
authors.initials: Y
authors.lastname: Pijnenburg
authors.forename: Brit
authors.initials: B
authors.lastname: Mollenhauer
authors.forename: Claudia
authors.initials: C
authors.lastname: Trenkwalder
authors.forename: John
authors.initials: J
authors.lastname: Van Swieten
authors.forename: Wan Zheng
authors.initials: WZ
authors.lastname: Chiu
authors.forename: Barbara
authors.initials: B
authors.lastname: Borroni
authors.forename: Ana
authors.initials: A
authors.lastname: Cámara
authors.forename: Perdita
authors.initials: P
authors.lastname: Cheshire
authors.forename: David R
authors.initials: DR
authors.lastname: Williams
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Lees
authors.forename: Rohan
authors.initials: R
authors.lastname: de Silva
mesh_terms: D000368:Aged; D015331:Cohort Studies; D006706:Homeostasis / Q000235:genetics / Q000276:immunology; D006801:Humans; D007118:Immunoassay / Q000379:methods* / Q000592:standards; D008875:Middle Aged; D016133:Polymerase Chain Reaction / Q000379:methods* / Q000592:standards; D020033:Protein Isoforms / Q000134:cerebrospinal fluid / Q000235:genetics / Q000276:immunology; D020449:Repetitive Sequences, Amino Acid / Q000235:genetics / Q000276:immunology; D015203:Reproducibility of Results; D024801:Tauopathies / Q000134:cerebrospinal fluid / Q000235:genetics / Q000378:metabolism*; D016875:tau Proteins / Q000134:cerebrospinal fluid* / Q000235:genetics / Q000276:immunology
chemical_list: D020033:Protein Isoforms; D016875:tau Proteins