Characterization of overall ceramide species in human stratum corneums⃞

• Main Authors: Yoshinori Masukawa, Hirofumi Narita, Eri Shimizu, Naoki Kondo, Yoshiya Sugai, Tsuyoshi Oba, Rika Homma, Junko Ishikawa, Yutaka Takagi, Takashi Kitahara, Yoshinori Takema, Katsumi Kita
• Format: Article
• Language: English
• Published: Elsevier 2008-07-01
• Series: Journal of Lipid Research
• Subjects: electrospray ionization tandem mass spectrometry; identification; isobaric; multi-mass chromatograms; normal-phase liquid chromatography; long chain-containing sphingoid
• Online Access: http://www.sciencedirect.com/science/article/pii/S0022227520347180

Ceramides (CERs) in human stratum corneum (SC) play physicochemical roles in determining barrier and water-holding functions of the skin, and specific species might be closely related to the regulation of keratinization, together with other CER-related lipids. Structures of those diverse CER species, however, have not been comprehensively revealed. The aim of this study was to characterize overall CER species in the SC. First, we constructed 3D multi-mass chromatograms of the overall CER species, based on normal-phase liquid chromatography (NPLC) connected to electrospray ionization-mass spectrometry (ESI-MS) using a gradient elution system and a postcolumn addition of a volatile salt-containing polar solvent. The CERs targeted from the 3D chromatograms were structurally analyzed using NPLC-ESI-tandem mass spectrometry (MS/MS), which resulted in the identification of 342 CER species in the inner forearm SC. This led to the discovery of a new CER class consisting of α-hydroxy fatty acid and dihydrosphingosine moieties, in addition to the 10 classes generally known. The results also revealed that those CERs contain long-chain (more than C18)-containing sphingoids and a great number of isobaric species. These novel results will contribute not only to physiochemical research on CERs in the SC but also to lipidomics approaches to CERs in the skin.