Phosphoneurofilament heavy chain and N-glycomics from the cerebrospinal fluid in amyotrophic lateral sclerosis

Background: Amyotrophic Lateral Sclerosis (ALS) is a fatal neurodegenerative disease of the motor neuron for which no clinically validated biomarkers have been identified. Methods: We have quantified by ELISA the biomarker phosphoneurofilament heavy chain (pNFH) in the cerebrospinal fluid (CSF) of ALS patients (n = 29) and age-matched control patients with other diseases (n = 19) by ELISA. Furthermore, we compared protein N-glycosylation of the CSF in ALS patients and controls, by applying a glycomics approach based on liquid chromatography and mass spectrometry. Results: pNFH levels were significantly higher in ALS patients in comparison with controls (P < 0.0001) in particular in fast progressors. The N-glycans found in the CSF were predominantly complex diantennary with sialic acid in alpha 2,3- and alpha 2,6-linkage, and bisecting N-acetylglucosamine-containing structures as well as peripherally fucosylated structures were found. As compared with controls the ALS group had a significant increase of a peak composed of the monosialylated diantennary glycans A2G2S(6)1 and FA2G2S(3)1 (P = 0.0348). Conclusions: Our results underscore the value of pNFH as a biomarker in ALS. In addition, we identified a variation of the N-glycosylation pattern in ALS, suggesting that this change should be explored in future studies as potential biomarker. (C) 2014 Elsevier B.V. All rights reserved.