Amino acid analyses of the exosome-eluted fractions from human serum by HPLC with fluorescence detection

Mayu Onozato; Yuriko Tanaka; Michitsune Arita; Tatsuya Sakamoto; Hideaki Ichiba; Kiyomi Sadamoto; Motonari Kondo; Takeshi Fukushima

doi:10.1016/j.plabm.2018.e00099

Amino acid analyses of the exosome-eluted fractions from human serum by HPLC with fluorescence detection

Pract Lab Med. 2018 Apr 22:12:e00099. doi: 10.1016/j.plabm.2018.e00099. eCollection 2018 Nov.

Authors

Mayu Onozato¹, Yuriko Tanaka², Michitsune Arita², Tatsuya Sakamoto¹, Hideaki Ichiba¹, Kiyomi Sadamoto³, Motonari Kondo², Takeshi Fukushima¹

Affiliations

¹ Faculty of Pharmaceutical Sciences, Toho University, 2-2-1 Miyama, Funabashi-shi, Chiba 274-8510, Japan.
² Department of Molecular Immunology, Toho University School of Medicine, 5-21-16 Omori-Nishi, Ota-ku, Tokyo 143-8540, Japan.
³ Faculty of Pharmaceutical Sciences, Yokohama College of Pharmacy, 601 Matano-cho, Totsuka-ku, Yokohama-shi, Kanagawa 245-0066, Japan.

Abstract

Objectives: Amino acid levels in serum or plasma are used for early detection and diagnosis of several diseases. The objective of this study was to analyze amino acid levels in serum exosomes, which have not been previously reported.

Design and methods: We investigated the amino acid composition of exosomes from human serum using HPLC with fluorescence detection.

Results: The composition ratios of His, Arg, Glu, Cys-Cys, Lys, and Tyr were significantly increased in the exosomes compared with those in the corresponding native serum. d-Ser, an endogenous co-agonist of the N-methyl-d-aspartate receptor, was also enriched in the exosome-eluted fraction.

Conclusions: Our results suggest that certain amino acids are enriched in the exosome-eluted fraction from human serum. These differences could have future diagnostic potential.

Keywords: Amino acid; Cystine; EVs, extracellular vesicles; Exosomes; HPLC, high-performance liquid chromatography; Human serum; NBD-F, 4-fluoro-7-nitro-2,1,3-benzoxadiazole; NMDA, N-methyl-D-aspartate; RIPA, radioimmunoprecipitation assay; d-serine.