Sulfatides in extracellular vesicles isolated from plasma of multiple sclerosis patients.

Extracellular vesicles (EVs) are membrane nanovesicles of diverse sizes secreted by different cell types and are involved in intercellular communication. EVs shuttle proteins, nucleic acids, and lipids that reflect their cellular origin and could mediate their biological function in recipient cells. EVs circulate in biological fluids and are considered as potential biomarkers that could be used to analyze and characterize disease development, course and response to treatment. EVs exhibit specific distribution of glycolipids and membrane organization, but little is known about the biological significance of this distribution or how it could contribute to pathological conditions such as multiple sclerosis (MS). We provide the first description of sulfatide composition in plasma-derived EVs by ultra-high-performance liquid chromatography tandem mass spectrometry. We found that EVs of different sizes showed C16:0 sulfatide but no detectable levels of C18:0, C24:0, or C24:1 sulfatide species. Small EVs isolated at 100,000 × g-enriched in exosomes-from plasma of patients with MS showed a significant increase of C16:0 sulfatide compared with healthy controls. Nanoparticle tracking analysis showed that the particle size distribution in MS plasma was significantly different compared with healthy controls. Characterization of small EVs isolated from MS plasma showed similar protein content and similar levels of exosomal markers (Alix, Rab-5B) and vesicular marker MHC class I (major histocompatibility complex class I) compared with healthy controls. Our findings indicate that C16:0 sulfatide associated with small EVs is a candidate biomarker for MS that could potentially reflect pathological changes associated with this disease and/or the effects of its treatment.