Selective inhibitors of a PAF biosynthetic enzyme lysophosphatidylcholine acyltransferase 2.
Platelet-activating factor (PAF) is a potent pro-inflammatory phospholipid mediator. In response to extracellular stimuli, PAF is rapidly biosynthesized by lyso-PAF acetyltransferase (lyso-PAFAT). Previously, we identified two types of lyso-PAFATs: lysophosphatidylcholine acyltransferase (LPCAT)1, mostly expressed in the lungs where it produces PAF and dipalmitoyl-phosphatidylcholine essential for respiration, and LPCAT2, which biosynthesizes PAF and phosphatidylcholine (PC) in the inflammatory cells. Under inflammatory conditions, LPCAT2, but not LPCAT1, is activated and upregulated to produce PAF. Thus, it is important to develop inhibitors specific for LPCAT2 in order to ameliorate PAF-related inflammatory diseases. Here, we report the first identification of LPCAT2-specific inhibitors, N-phenylmaleimide derivatives, selected from a 174,000-compound library using fluorescence-based high-throughput screening followed by the evaluation of the effects on LPCAT1 and LPCAT2 activities, cell viability, and cellular PAF production. Selected compounds competed with acetyl-CoA for the inhibition of LPCAT2 lyso-PAFAT activity and suppressed PAF biosynthesis in mouse peritoneal macrophages stimulated with a calcium ionophore. These compounds had low inhibitory effects on LPCAT1 activity, indicating that adverse effects on respiratory functions may be avoided. The identified compounds and their derivatives will contribute to the development of novel drugs for PAF-related diseases and facilitate the analysis of LPCAT2 functions in phospholipid metabolism in vivo.
Department of Lipid Signaling, Research Institute, National Center for Global Health and Medicine, Shinjuku-ku, Tokyo 162-8655, Japan Department of Respiratory Medicine, Faculty of Medicine, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan.
Megumi
M
Tarui
Department of Lipid Signaling, Research Institute, National Center for Global Health and Medicine, Shinjuku-ku, Tokyo 162-8655, Japan Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012, Japan.
Hideo
H
Shindou
Open Innovation Center for Drug Discovery, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan.
Kazuo
K
Kumagai
Department of Lipid Signaling, Research Institute, National Center for Global Health and Medicine, Shinjuku-ku, Tokyo 162-8655, Japan Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan.
Ryo
R
Morimoto
Department of Lipid Signaling, Research Institute, National Center for Global Health and Medicine, Shinjuku-ku, Tokyo 162-8655, Japan.
Takeshi
T
Harayama
Department of Lipid Signaling, Research Institute, National Center for Global Health and Medicine, Shinjuku-ku, Tokyo 162-8655, Japan.
Tomomi
T
Hashidate
Open Innovation Center for Drug Discovery, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan.
Hirotatsu
H
Kojima
Open Innovation Center for Drug Discovery, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan.
Takayoshi
T
Okabe
Open Innovation Center for Drug Discovery, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan.
Tetsuo
T
Nagano
Department of Respiratory Medicine, Faculty of Medicine, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan.
Takahide
T
Nagase
Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan.
Takao
T
Shimizu
D008243:1-Acylglycerophosphocholine O-Acyltransferase / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D000123:Acetyltransferases / Q000037:antagonists & inhibitors / Q000378:metabolism; D000818:Animals; D004791:Enzyme Inhibitors / Q000737:chemistry* / Q000494:pharmacology*; D017737:Macrophages, Peritoneal / Q000201:enzymology*; D051379:Mice; D010972:Platelet Activating Factor / Q000096:biosynthesis*; D000067996:RAW 264.7 Cells
D004791:Enzyme Inhibitors; D010972:Platelet Activating Factor; D000123:Acetyltransferases; D008243:1-Acylglycerophosphocholine O-Acyltransferase; C000592232:LPCAT2 protein, mouse; C526203:Lpcat1 protein, mouse; C046035:1-alkylglycerophosphocholine acetyltransferase
LPCAT2 inhibitor; N-phenylmaleimide derivatives; TSI-01; fluorescent probe; high-throughput screening; inflammation; lipid mediator; lyso-PAF acetyltransferase; lysophospholipid acyltransferase; platelet-activating factor