Human cerebrospinal fluid 6E10-immunoreactive protein species contain amyloid precursor protein fragments.

• In a previous study, we reported that levels of two types of protein species-a type of ~55-kDa species and a type of ~15-kDa species-are elevated in the lumbar cerebrospinal fluid (CSF) of cognitively intact elderly individuals who are at risk for Alzheimer's disease (AD). These species are immunoreactive to the monoclonal antibody 6E10, which is directed against amino acids 6-10 of amyloid-β (Aβ), and their levels correlate with levels of total tau and tau phosphorylated at Thr181. In this study, we investigated the molecular composition of these AD-related proteins using immunoprecipitation (IP)/Western blotting coupled with IP/mass spectrometry. We show that canonical Aβ1-40/42 peptides, together with amyloid-β precursor protein (APP) fragments located N-terminally of Aβ, are present in the ~55-kDa, 6E10-immunoreactive species. We demonstrate that APP fragments located N-terminally of Aβ, plus the N-terminal region of Aβ, are present in the ~15-kDa, 6E10-immunoreactive species. These findings add to the catalog of AD-related Aβ/APP species found in CSF and should motivate further study to determine whether these species may serve as biomarkers of disease progression.

Subject headings

MEDICIN OCH HÄLSOVETENSKAP  -- Medicinska och farmaceutiska grundvetenskaper -- Neurovetenskaper (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Basic Medicine -- Neurosciences (hsv//eng)

Keyword

Aged

Aged

80 and over

Alzheimer Disease

cerebrospinal fluid

diagnosis

Amino Acid Sequence

Amyloid beta-Peptides

cerebrospinal fluid

chemistry

immunology

Biomarkers

cerebrospinal fluid

Blotting

Western

Disease Progression

Female

Humans

Immunoprecipitation

Male

Mass Spectrometry

Middle Aged

Molecular Weight

Peptide Fragments

cerebrospinal fluid

chemistry

immunology

Publication and Content Type

ref (subject category)

art (subject category)