title: Analysis of liposoluble carboxylic acids metabolome in human serum by stable isotope labeling coupled with liquid chromatography-mass spectrometry.
abstract: Fatty acids (FAs) are groups of liposoluble carboxylic acids (LCAs) and play important roles in various physiological processes. Abnormal contents or changes of FAs are associated with a series of diseases. Here we developed a strategy with stable isotope labeling combined with liquid chromatography-tandem mass spectrometry (IL-LC-MS) analysis for comprehensive profiling and relative quantitation of LCAs in human serum. In this strategy, a pair of isotope labeling reagents (2-dimethylaminoethylamine (DMED)) and d4-2-dimethylaminoethylamine (d4-DMED) were employed to selectively label carboxyl groups of LCAs. The DMED and d4-DMED labeled products can lose four characteristic neutral fragments of 45 and 49Da or 63 and 67Da in collision-induced dissociation. Therefore, quadruple neutral loss scan (QNLS) mode was established and used for non-targeted profiling of LCAs. The peak pairs of DMED and d4-DMED labeling with the same retention time, intensity and characteristic mass differences were extracted from the two NLS spectra respectively, and assigned as potential LCA candidates. Using this strategy, 241 LCA candidates were discovered in the human serum; 156 carboxylic acid compounds could be determined by searching HMDB and METLIN databases (FAs are over 90%) and 21 of these LCAs were successfully identified by standards. Subsequently, a modified pseudo-targeted method with multiple reaction monitoring (MRM) detection mode was developed and used for relative quantification of LCAs in human serum from type 2 diabetes mellitus (T2DM) patients and healthy controls. As a result, 81 LCAs were found to have significant difference between T2DM patients and healthy controls. Taken together, the isotope labeling combined with tandem mass spectrometry analysis demonstrated to be a powerful strategy for identification and quantification of LCA compounds in serum samples.
authors.affiliation: Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), Department of Chemistry, Wuhan University, Wuhan 430072, PR China.
authors.forename: Quan-Fei
authors.initials: QF
authors.lastname: Zhu
authors.affiliation: Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), Department of Chemistry, Wuhan University, Wuhan 430072, PR China.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), Department of Chemistry, Wuhan University, Wuhan 430072, PR China.
authors.forename: Ping
authors.initials: P
authors.lastname: Liu
authors.affiliation: Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), Department of Chemistry, Wuhan University, Wuhan 430072, PR China.
authors.forename: Shu-Jian
authors.initials: SJ
authors.lastname: Zheng
authors.affiliation: Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), Department of Chemistry, Wuhan University, Wuhan 430072, PR China.
authors.forename: Ke
authors.initials: K
authors.lastname: Peng
authors.affiliation: Center for Gene Diagnosis, Zhongnan Hospital of Wuhan University, Donghu Rd 169, Wuchang District, Wuhan 430071, PR China.
authors.forename: Qian-Yun
authors.initials: QY
authors.lastname: Deng
authors.affiliation: Center for Gene Diagnosis, Zhongnan Hospital of Wuhan University, Donghu Rd 169, Wuchang District, Wuhan 430071, PR China.
authors.forename: Fang
authors.initials: F
authors.lastname: Zheng
authors.affiliation: Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), Department of Chemistry, Wuhan University, Wuhan 430072, PR China.
authors.forename: Bi-Feng
authors.initials: BF
authors.lastname: Yuan
authors.affiliation: Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), Department of Chemistry, Wuhan University, Wuhan 430072, PR China. Electronic address: yqfeng@whu.edu.cn.
authors.forename: Yu-Qi
authors.initials: YQ
authors.lastname: Feng
mesh_terms: D000328:Adult; D000368:Aged; D001786:Blood Glucose / Q000032:analysis; D002264:Carboxylic Acids / Q000097:blood*; D016022:Case-Control Studies; D002851:Chromatography, High Pressure Liquid; D003924:Diabetes Mellitus, Type 2 / Q000378:metabolism / Q000473:pathology; D016002:Discriminant Analysis; D005227:Fatty Acids / Q000737:chemistry / Q000378:metabolism*; D005260:Female; D006801:Humans; D007553:Isotope Labeling; D008297:Male; D055442:Metabolome; D008875:Middle Aged; D025341:Principal Component Analysis; D053719:Tandem Mass Spectrometry
chemical_list: D001786:Blood Glucose; D002264:Carboxylic Acids; D005227:Fatty Acids
keywords: Fatty acid; Isotope labeling; Mass spectrometry; Multiple reaction monitoring; Quadruple neutral loss scan; Type 2 diabetes mellitus