caa a22 4500 606236414 CHVBK 20210128101247.0 cr unu---uuuuu 210128e20150201xx s 000 0 eng 10.1007/s11010-014-2268-z doi (NATIONALLICENCE)springer-10.1007/s11010-014-2268-z Sphingosine 1-phosphate lyase inhibition by 2-acetyl-4-(tetrahydroxybutyl)imidazole (THI) under conditions of vitamin B6 deficiency [Elektronische Daten] [Mamoru Ohtoyo, Masakazu Tamura, Nobuo Machinaga, Fumihito Muro, Ryuji Hashimoto] Caramel food colorant 2-acetyl-4-(tetrahydroxybutyl)imidazole (THI) causes lymphopenia in animals through sphingosine 1-phosphate lyase (SPL) inhibition. However, this mechanism of action is partly still controversial because THI did not inhibit SPL in vitro either in cell-free or in cell-based systems. It is thought that the in vitro experimental conditions which have been used so far were not suitable for the evaluation of SPL inhibition, especially in case of cell-based experiments. We speculated that the key factor might be the coenzyme pyridoxal 5′-phosphate (PLP), an active form of vitamin B6 (VB6), because media used in cell-based assays usually contain an excess amount of VB6 which leads to the activation of SPL. By the use of VB6-deficient culture medium, we could regulate apo- (without PLP) and holo- (with PLP) SPL enzyme in cultured cells, resulting in the successful detection of SPL inhibition by THI. Although the observed inhibitory effect was not as strong as that of 4-deoxypyridoxine (a VB6 analog SPL inhibitor), these findings may be useful for further understanding the mechanism of action of THI. Springer Science+Business Media New York, 2014 2-Acetyl-4-(tetrahydroxybutyl)imidazole nationallicence Sphingosine 1-phosphate nationallicence S1P lyase nationallicence Vitamin B6 nationallicence 4-Deoxypyridoxine nationallicence Ohtoyo Mamoru New Modality Research Laboratories, R&D Division, Daiichi Sankyo Co., Ltd., 1-2-58 Hiromachi, Shinagawa-ku, 140-8710, Tokyo, Japan aut Tamura Masakazu Biologics Pharmacology Research Laboratories, R&D Division, Daiichi Sankyo Co., Ltd., 1-2-58 Hiromachi, Shinagawa-ku, 140-8710, Tokyo, Japan aut Machinaga Nobuo Medicinal Chemistry Research Laboratories, R&D Division, Daiichi Sankyo Co., Ltd., 1-2-58 Hiromachi, Shinagawa-ku, 140-8710, Tokyo, Japan aut Muro Fumihito Vaccine Business Strategy Department, Vaccine Business Intelligence Division, Daiichi Sankyo Co., Ltd., 3-5-1, Nihonbashi Honcho, Chuo-ku, 103-8426, Tokyo, Japan aut Hashimoto Ryuji New Modality Research Laboratories, R&D Division, Daiichi Sankyo Co., Ltd., 1-2-58 Hiromachi, Shinagawa-ku, 140-8710, Tokyo, Japan aut Molecular and Cellular Biochemistry Springer US; http://www.springer-ny.com 400/1-2(2015-02-01), 125-133 0300-8177 400:1-2<125 2015 400 11010 https://doi.org/10.1007/s11010-014-2268-z text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s11010-014-2268-z text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Ohtoyo Mamoru New Modality Research Laboratories, R&D Division, Daiichi Sankyo Co., Ltd., 1-2-58 Hiromachi, Shinagawa-ku, 140-8710, Tokyo, Japan aut NATIONALLICENCE 700 1- Tamura Masakazu Biologics Pharmacology Research Laboratories, R&D Division, Daiichi Sankyo Co., Ltd., 1-2-58 Hiromachi, Shinagawa-ku, 140-8710, Tokyo, Japan aut NATIONALLICENCE 700 1- Machinaga Nobuo Medicinal Chemistry Research Laboratories, R&D Division, Daiichi Sankyo Co., Ltd., 1-2-58 Hiromachi, Shinagawa-ku, 140-8710, Tokyo, Japan aut NATIONALLICENCE 700 1- Muro Fumihito Vaccine Business Strategy Department, Vaccine Business Intelligence Division, Daiichi Sankyo Co., Ltd., 3-5-1, Nihonbashi Honcho, Chuo-ku, 103-8426, Tokyo, Japan aut NATIONALLICENCE 700 1- Hashimoto Ryuji New Modality Research Laboratories, R&D Division, Daiichi Sankyo Co., Ltd., 1-2-58 Hiromachi, Shinagawa-ku, 140-8710, Tokyo, Japan aut NATIONALLICENCE 773 0- Molecular and Cellular Biochemistry Springer US; http://www.springer-ny.com 400/1-2(2015-02-01), 125-133 0300-8177 400:1-2<125 2015 400 11010