Exploration of the structural diversity and distribution pattern of gangliosides and sulfatides in mouse brain tissues and biomarkers for Parkinson's Disease.

Abstract

BACKGROUND: Acidic glycosphingolipids (GSLs), including gangliosides (GAs) and sulfatides (STs), play key roles in intercellular signalling and neurodegenerative diseases. However, their comprehensive characterization remains challenging because of structural complexity, abundance variation, and interference from isomers and isotopes. This study aimed to systematically profile GAs and STs in mouse brain tissues and explore their potential as biomarkers in a Parkinson’s disease (PD) model. METHODS: Prefractionation in combination with UHPLC-Q-TOF MS was employed for high-resolution MS and MS/MS analysis of acidic GSLs. Quantitative structure–retention relationship (QSRR) models were constructed from identified structures and retention times (RTs) to predict RTs and provide complementary support for MS/MS-based annotation. Dynamic multiple reaction monitoring (dMRM) on UHPLC-QQQ MS was applied to quantify GSLs, followed by a comparative analysis of PD and control mouse brain tissues. RESULTS: A total of 220 acidic GSLs were characterized, including 173 GAs (21 subclasses) and 47 STs (3 subclasses), representing the most extensive profile reported from mouse brain tissues, among which 75 GAs and 29 STs are, to the best of the authors’ knowledge, newly reported here. The QSRR model provided retention time predictions supporting the tentative annotation of eight rare acidic GSLs with insufficient MS/MS data. Among the identified species, Monosialogangliosides (GM) were the most abundant subclass, with GM1 and GM3 predominant. GD1a was the major disialoganglioside (GD) species, and the trisialoganglioside (GT), tetrasialoganglioside (GQ), and pentasialoganglioside (GP) subclasses were identified as GT1b, GQ1b, and GP1c, respectively. The STs were mainly of the SulfoHex type. O-acetylation was frequent in GQ species, while fucosylation and GalNAc attachment were primarily associated with GM and GD species. The sphingoid bases were mainly d18:0, d18:1, d20:0, and d20:1, while the N-acyl chains spanned C16:0–C24:0. For quantification, a method covering 17 subclasses enabled the simultaneous measurement of 89 GAs and 27 STs, representing the broadest quantification coverage in PD mouse brain studies to date. Further analysis revealed significant alterations in 20 GAs and 7 STs in PD, with GQ1b reported for the first time as a potential PD-related biomarker, and pathway analysis indicated disruption of b-series GA biosynthesis. CONCLUSIONS: This study provides a comprehensive profile of acidic GSLs in mouse brain tissues and reveals GQ alterations with pathway disruptions in PD, offering molecular evidence linking acidic GSL metabolism to this disease.