Galabiosylceramide is present in human cerebrospinal fluid

Area of Science:

• Biochemistry
• Neuroscience
• Genetics

Background:

• Cerebrospinal fluid (CSF) contains glycosphingolipids, including lactosylceramide (LacCer).
• Galabiosylceramide (Gb2), a structural isomer of LacCer, is a ceramide dihexoside (CDH) degraded by alpha-galactosidase A (GLA).
• Genetic GLA deficiency causes Fabry disease, leading to Gb2 accumulation, but Gb2 presence in CSF was previously unreported.

Purpose of the Study:

• To investigate the presence of ceramide dihexosides (CDH), specifically Gb2, in human cerebrospinal fluid (CSF).
• To establish a baseline for Gb2 levels in CSF for potential diagnostic applications in lysosomal storage disorders.

Main Methods:

• Isolation of CDH fractions from CSF of patients with idiopathic normal pressure hydrocephalus and healthy controls.
• Detection of Gb2 using Shiga toxin, which specifically binds to the Galα(1,4)Galβ structure.
• Analysis of isolated CDH fractions using hydrophilic interaction chromatography (HILIC)-electrospray ionization tandem mass spectrometry (ESI-MS/MS) to separate and identify LacCer and Gb2.

Main Results:

• Purified CDH fractions from CSF reacted positively with Shiga toxin, indicating the presence of the Galα(1,4)Galβ structure.
• HILIC-ESI-MS/MS analysis confirmed the presence of both Gb2 and LacCer in the isolated CSF fractions.
• Gb2 was detected in the CSF of both patients and neurologically normal control subjects.

Conclusions:

• This study reports for the first time the presence of galabiosylceramide (Gb2) in human cerebrospinal fluid (CSF).
• The findings suggest that Gb2 can be measured in CSF, potentially aiding in the diagnosis and monitoring of Fabry disease and other Gb2-related metabolic disorders.
• Further research is warranted to explore the physiological role and diagnostic utility of Gb2 in CSF.