Newly synthetic ceramide-1-phosphate analogs; their uptake, intracellular localization, and roles as an inhibitor of cytosolic phospholipase A₂α and inducer of cell toxicity

详细信息    查看全文

• 作者：Tomohiko Makiyama ; Nobuo Nagasaka ; Yuuya Houjyo ; Erika Yamaura ; Hiroyuki Nakamura ; Yuuki Koide ; Atsushi Nishida ; Toshihiko Murayama
• 关键词：Ceramide-1-phosphate (C1P) ; Methyl-ester analogs of C1P ; Ceramide kinase ; Cell toxicity ; Arachidonic acid ; Phospholipase A₂
• 刊名：Biochemical Pharmacology
• 出版年：2010
• 出版时间：1 November 2010
• 年：2010
• 卷：80
• 期：9
• 页码：1396-1406
• 全文大小：1838 K

文摘

Ceramide-1-phosphate (C1P) regulates cellular functions including arachidonic acid (AA) metabolism and modulates cell fate. The mechanism by which C1P is taken up is unclear, and the development of lipophilic analogs may be useful for regulating C1P's actions. We synthesized new mono- and di-methyl-ester (MM and DM, respectively) analogs of C1P with N-acyl chains of different lengths, and examined their effects on AA release and cell toxicity. Short-N-acyl-DM-C1P analogs including C5- and C6-DM-C1P, but not long-N-acyl-DM-C1P analogs, inhibited the release of AA mediated by α type cytosolic phospholipase A₂ (cPLA₂α) in Chinese hamster ovary (CHO) cells and the enzymatic activity. Short-N-acyl-DM-C1P analogs including C6-DM-C1P caused morphological changes with cell toxicity 24 h after the treatment in three cells lines (CHO, L929, and RLC-18 cells), although the role of AA in the toxicity was not clear. Neither long-N-acyl-DM-C1P analogs nor MM-C1P analogs including C6-MM-C1P affected cPLA₂α activity and cell toxicity. Similar to C6-ceramide having a 4-nitrobenzo-2-oxa-1,3-diazole (NBD) group on a C6-N-acyl chain (NBD-C6-ceramide), NBD-C6-DM-C1P and C6-DM-C1P-NBD (with a C6-N-acyl chain and an NBD-labeled C14-alkyl chain) were accumulated in the Golgi complex, although less C6-DM-C1P-NBD than NBD-C6-DM-C1P was taken up. NBD-C6-ceramide was converted to various metabolites including NBD-C6-sphingomyelin, but both NBD-C6-DM-C1P and C6-DM-C1P-NBD were stable in cells within 2 h. The short-N-acyl-DM-C1P analogs acted directly as an inhibitor of cPLA₂α and an inducer of cell toxicity, and may be useful for the regulation of ceramide/C1P-regulated responses.