LC–MS/MS assay for the investigation of acetylated Alpha-synuclein in serum from postmortem Alzheimer’s disease pathology

• Published in: Journal of chromatography. B, Analytical technologies in the biomedical and life sciences Analytical technologies in the biomedical and life sciences, 2021-09, Vol.1181, p.122885-122885, Article 122885
• Main Authors: Uchida, Kazuki, Morikawa, Kazunori, Muguruma, Yoshio, Hosokawa, Masato, Tsutsumiuchi, Kaname, Kaneda, Daita, Hashizume, Yoshio, Akatsu, Hiroyasu, Inoue, Koichi
• Format: Article
• Language: English
• Subjects: Acetylated N-terminal site; Acetylation; Alpha-synuclein; alpha-Synuclein - blood; Alzheimer Disease - pathology; Alzheimer’s disease; Chromatography, Liquid - methods; Humans; Limit of Detection; Linear Models; Liquid chromatography tandem mass spectrometry; Reproducibility of Results; Serum; Tandem Mass Spectrometry - methods
• ISSN: 1570-0232; 1873-376X
• DOI: 10.1016/j.jchromb.2021.122885

•A LC-MS/MS assay for acetylated N-terminal α-Syn peptides was developed.•A tryptic approach was applied to preparation of α-Syn1-6 and Ac-α-Syn1-6 in serum.•Developed assay was applied to serum based on postmortem AD pathology.•Our preliminarily results showed that single Ac-α-Syn levels from serum were inferred with nonspecific biomarkers of AD pathology. Alpha-synuclein (α-Syn), a neuronal protein, has been linked to the inflammation and development of neurodegenerative diseases. In a number of neurodegenerations, α-Syn has been investigated in the central nervous system and cerebrospinal fluid. However, there are few studies concerning the variations in peripheral α-Syn in postmortem Alzheimer’s disease (AD) pathology. In this study, the quantitative procedure for the determination of peripheral acetylated α-Syn regarding N-terminal amino acid’s site (α-Syn1-6; MDVFMK and Ac-α-Syn1-6; Ac-MDVFMK) was developed using liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) and tryptic digestion without antibody. Serum samples were selected from postmortem specimens based on autopsy pathological examination of AD remark. The LC-MS/MS assay with ACQUITY UPLC BEH C18 column was applied on the basis of electrospray positive ionization. When subjected to N-terminal α-Syn peptides using MonoSpin Typsin HP preparation, doubly- and singly-charged α-Syn1-6 and Ac-α-Syn1-6 ions were observed at m/z 386 > 104 and m/z 813 > 72, respectively, which correspond to quantitative profiling with internal standards. In the calibration, the range of 10–1000 nmol/L showed r2 = 0.999 and recovery from 86.0% to 115.0% (RSD