The validity of α-synuclein (α-Syn) as a biomarker for Parkinson’s disease (PD) is still under investigation. Conventional methods for capture and quantitation of α-Syn protein in human samples are primarily based on anti-α-Syn antibodies. Specific and competent antibodies were raised against α-Syn. However, capture by anti-α-Syn antibodies may be limited to specific epitope recognition, attributed to protein structure or post-translational modifications. Hence, antibody-based methods for α-Syn capture raise a concern regarding their efficacy to detect the intracellular, unfolded α-Syn pool. An alternative is α-Syn capture by membrane lipids, i.e., to utilize the biochemical property of α-Syn to specifically bind membrane lipids and acquire a characteristic structure following binding. We determined α-Syn levels in human samples using immobilized lipids for α-Syn capture. The lipids used for α-Syn capture consist of phosphatidyl inositol (PI), phosphatidyl serine (PS), and phosphatidyl ethanolamine (PE). Addition of mono-sialoganglioside, GM1 ganglioside, to the immobilized lipids significantly improved α-Syn detection. Following capture, the lipid-bound α-Syn was detected using an anti-α-Syn antibody. Total α-Syn levels in whole blood cells (WBC), cerebrospinal fluid (CSF), and saliva were determined by the lipid-ELISA method.
Bibliographical noteFunding Information:
The authors would like to thank Prof. Robert W. Ledeen from the University of Medicine and Dentistry of New Jersey) for helpful discussions. This work was supported by the following grants from The Michael J. Fox Foundation for Parkinson's Research (MJFF): grant 2013, “Alpha-synuclein and other biomarkers in biological samples of LRRK2 Parkinson’s disease”; grant # 11899: “Total and proteinase-K resistant α-Syn levels in blood pellets, determined by a novel phospholipid ELISA assay, as potential markers for PD”.
© 2016, Springer-Verlag Berlin Heidelberg.
- Parkinson’s disease