Phosphorylated α‐synuclein can be detected in blood plasma and is potentially a useful biomarker for Parkinson's disease

Abstract

ABSTRACT Parkinson's disease (PD) is characterized by the presence of Lewy bodies containing phosphorylated and aggregated α‐synuclein (α‐syn). α‐Syn is present in human body fluids, including blood plasma, and is a potential biomarker for PD. Immunoassays for total and oligomeric forms of both normal and phosphorylated (at Ser‐129) α‐syn have been used to assay plasma samples from a longitudinal cohort of 32 patients with PD (sampled at mo 0, 1, 2, 3), as well as single plasma samples from a group of 30 healthy control participants. The levels of α‐syn in plasma varied greatly between individuals, but were remarkably consistent over time within the same individual with PD. The mean level of phospho‐α‐syn was found to be higher ( P =0.053) in the PD samples than the controls, whereas this was not the case for total α‐syn ( P= 0.244), oligo‐α‐syn ( P =0.221), or oligo‐phospho‐α‐syn ( P =0.181). Immunoblots of plasma revealed bands (at 21, 24, and 50‐60 kDa) corresponding to phosphorylated α‐syn. Thus, phosphorylated α‐syn can be detected in blood plasma and shows more promise as a diagnostic marker than the nonphosphorylated protein. Longitudinal studies undertaken over a more extended time period will be required to determine whether α‐syn can act as a marker of disease progression.—Foulds, P. G., Mitchell, J. D., Parker, A., Turner, R., Green, G., Diggle, P., Hasegawa, M., Taylor, M., Mann, D., Allsop, D. Phosphorylated α‐synuclein can be detected in blood plasma and is potentially a useful biomarker for Parkinson's disease. FASEB J. 25, 4127–4137 (2011). www.fasebj.org