Long-Chain Base (LCB)-Targeted Lipidomics Study Uncovering the Presence of a Variety of LCBs in Mammalian Blood

• Main Authors: Mari Ohira, Torayuki Okuyama, Ryuichi Mashima
• Format: Article
• Language: English
• Published: MDPI AG 2020-10-01
• Series: Separations
• Subjects: long-chain base; sphingolipid; mass spectrometry
• Online Access: https://www.mdpi.com/2297-8739/7/4/57

Globotriaosylsphingosine (LysoGb₃) is a biomarker for Fabry disease (OMIM 301500) that contains long-chain bases (LCBs) as a building block. There have been several studies proposing that LysoGb₃ forms with distinct LCBs could be putative disease subtype-related biomarkers for this congenital disorder; however, there have been no detailed multiple reaction monitoring-based studies examining the LCB distribution in this lysosphingolipid. To achieve this, we established an assay procedure that aimed at elucidating the LCB-targeted lipidome using liquid chromatography–tandem mass spectrometry. Consistent with previous studies, we found d18:1 to be the major LCB species of the LysoGb₃ in pooled human plasma, while some atypical LCBs, such as d18:2, d18:0, t18:1, d16:1, and d17:1, were detected as minor fractions. When the same methodology was applied to fetal bovine serum (FBS) as a positive control, we identified additional unique LCB species, such as t18:0, d20:1, t19:1, and t21:1, in herbivore LysoGb₃. Furthermore, we found an elevation of sphingosine and LysoGb₃, which are N-deacylated forms of ceramide and Gb₃, respectively, in FBS, suggesting that ceramidase activity may be involved in this process. Thus, our LCB-targeted lipidomics data revealed that mammalian LCBs in glycosphingolipids have a greater variety of molecular species than previously expected.