Dataset Information

Identification of unusual oxysterols and bile acids with 7-oxo or 3?,5?,6?-trihydroxy functions in human plasma by charge-tagging mass spectrometry with multistage fragmentation.

ABSTRACT: 7-Oxocholesterol (7-OC), 5,6-epoxycholesterol (5,6-EC), and its hydrolysis product cholestane-3?,5?,6?-triol (3?,5?,6?-triol) are normally minor oxysterols in human samples; however, in disease, their levels may be greatly elevated. This is the case in plasma from patients suffering from some lysosomal storage disorders, e.g., Niemann-Pick disease type C, or the inborn errors of sterol metabolism, e.g., Smith-Lemli-Opitz syndrome and cerebrotendinous xanthomatosis. A complication in the analysis of 7-OC and 5,6-EC is that they can also be formed ex vivo from cholesterol during sample handling in air, causing confusion with molecules formed in vivo. When formed endogenously, 7-OC, 5,6-EC, and 3?,5?,6?-triol can be converted to bile acids. Here, we describe methodology based on chemical derivatization and LC/MS with multistage fragmentation (MSn) to identify the necessary intermediates in the conversion of 7-OC to 3?-hydroxy-7-oxochol-5-enoic acid and 5,6-EC and 3?,5?,6?-triol to 3?,5?,6?-trihydroxycholanoic acid. Identification of intermediate metabolites is facilitated by their unusual MSn fragmentation patterns. Semiquantitative measurements are possible, but absolute values await the synthesis of isotope-labeled standards.

SUBMITTER: Griffiths WJ

PROVIDER: S-EPMC5983402 | biostudies-literature | 2018 Jun

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Identification of unusual oxysterols and bile acids with 7-oxo or 3β,5α,6β-trihydroxy functions in human plasma by charge-tagging mass spectrometry with multistage fragmentation.

Griffiths William J WJ Gilmore Ian I Yutuc Eylan E Abdel-Khalik Jonas J Crick Peter J PJ Hearn Thomas T Dickson Alison A Bigger Brian W BW Wu Teresa Hoi-Yee TH Goenka Anu A Ghosh Arunabha A Jones Simon A SA Wang Yuqin Y

Journal of lipid research 20180406 6

7-Oxocholesterol (7-OC), 5,6-epoxycholesterol (5,6-EC), and its hydrolysis product cholestane-3β,5α,6β-triol (3β,5α,6β-triol) are normally minor oxysterols in human samples; however, in disease, their levels may be greatly elevated. This is the case in plasma from patients suffering from some lysosomal storage disorders, e.g., Niemann-Pick disease type C, or the inborn errors of sterol metabolism, e.g., Smith-Lemli-Opitz syndrome and cerebrotendinous xanthomatosis. A complication in the analysis ...[more]

PMID: 29626102

Similar Datasets

Project description:The present study describes the synthesis, characterization, and in vitro molecular interactions of a steroid 3β,6β-diacetoxy-5α-cholestan-5-ol. Through conventional and solid-state methods, a cholestane derivative was successfully synthesized, and a variety of analytical techniques were employed to confirm its identity, including high-resolution mass spectrometry (HRMS), Fourier transforms infrared (FT-IR), nuclear magnetic resonance (NMR), elemental analysis, and X-ray single-crystal diffraction. Optimizing the geometry of the steroid was undertaken using density functional theory (DFT), and the results showed great concordance with the data from the experiments. Fluorescence spectral methods and ultraviolet-vis absorption titration were employed to study the in vitro molecular interaction of the steroid regarding human serum albumin (HSA). The Stern-Volmer, modified Stern-Volmer, and thermodynamic parameters' findings showed that steroids had a significant binding affinity to HSA and were further investigated by molecular docking studies to understand the participation of active amino acids in forming non-bonding interactions with steroids. Fluorescence studies have shown that compound 3 interacts with human serum albumin (HSA) through a static quenching mechanism. The binding affinity of compound 3 for HSA was found to be 3.18 × 104 mol-1, and the Gibbs free energy change (ΔG) for the binding reaction was -9.86 kcal mol-1 at 298 K. This indicates that the binding of compound 3 to HSA is thermodynamically favorable. The thermodynamic parameters as well as the binding score obtained from molecular docking at various Sudlow's sites was -8.2, -8.5, and -8.6 kcal/mol for Sites I, II, and III, respectively, supporting the system's spontaneity. Aside from its structural properties, the steroid demonstrated noteworthy antioxidant activity, as evidenced by its IC50 value of 58.5 μM, which is comparable to that of ascorbic acid. The findings presented here contribute to a better understanding of the pharmacodynamics of steroids.

Dataset Information

Identification of unusual oxysterols and bile acids with 7-oxo or 3?,5?,6?-trihydroxy functions in human plasma by charge-tagging mass spectrometry with multistage fragmentation.

Publications

Identification of unusual oxysterols and bile acids with 7-oxo or 3β,5α,6β-trihydroxy functions in human plasma by charge-tagging mass spectrometry with multistage fragmentation.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets