Involvement of N-acylethanolamine-hydrolyzing acid amidase in the degradation of anandamide and other N-acylethanolamines in macrophages.
Bioactive N-acylethanolamines including the endocannabinoid anandamide are known to be hydrolyzed to fatty acids and ethanolamine by fatty acid amide hydrolase (FAAH). In addition, we recently cloned an isozyme termed "N-acylethanolamine-hydrolyzing acid amidase (NAAA)", which is active only at acidic pH [Tsuboi, Sun, Okamoto, Araki, Tonai, Ueda, J. Biol. Chem. 285 (2005) 11082-11092]. However, physiological roles of NAAA remained unclear. Here, we examined a possible contribution of NAAA to the degradation of various N-acylethanolamines in macrophage cells. NAAA mRNA as well as FAAH mRNA was detected in several macrophage-like cells, including RAW264.7, and mouse peritoneal macrophages. The homogenates of RAW264.7 cells showed both the NAAA and FAAH activities which were confirmed with the aid of their respective specific inhibitors, N-cyclohexanecarbonylpentadecylamine (CCP) and URB597. As analyzed with intact cells, RAW264.7 cells and peritoneal macrophages degraded anandamide, N-palmitoylethanolamine, N-oleoylethanolamine, and N-stearoylethanolamine. Pretreatment of the cells with CCP or URB597 partially inhibited the degradation, and a combination of the two compounds caused more profound inhibition. In contrast, the anandamide hydrolysis in mouse brain appeared to be principally attributable to FAAH despite the expression of NAAA in the brain. These results suggested that NAAA and FAAH cooperatively degraded various N-acylethanolamines in macrophages.
Sun
Yong-Xin
YX
Department of Biochemistry, Kagawa University School of Medicine, 1750-1 Ikenobe, Miki, Kagawa 761-0793, Japan.
Tsuboi
Kazuhito
K
Zhao
Li-Ying
LY
Okamoto
Yasuo
Y
Lambert
Didier M
DM
Ueda
Natsuo
N
D000577:Amides / Q000494:pharmacology; D000581:Amidohydrolases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D001095:Arachidonic Acids / Q000378:metabolism*; D001549:Benzamides / Q000494:pharmacology; D001921:Brain / Q000201:enzymology; D002219:Carbamates / Q000494:pharmacology; D002460:Cell Line; D045744:Cell Line, Tumor; D063388:Endocannabinoids; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004983:Ethanolamines / Q000378:metabolism*; D015870:Gene Expression / Q000235:genetics; D006801:Humans; D007668:Kidney / Q000201:enzymology; D008099:Liver / Q000201:enzymology; D008168:Lung / Q000201:enzymology; D008264:Macrophages / Q000187:drug effects / Q000201:enzymology*; D017737:Macrophages, Peritoneal / Q000187:drug effects / Q000201:enzymology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D053284:Polyunsaturated Alkamides; D051381:Rats; D017208:Rats, Wistar; D020298:U937 Cells; D000099252:Fatty Acid Amide Hydrolases
D000577:Amides; D000581:Amidohydrolases; D001095:Arachidonic Acids; D001549:Benzamides; D002219:Carbamates; D063388:Endocannabinoids; D004791:Enzyme Inhibitors; D004983:Ethanolamines; D053284:Polyunsaturated Alkamides; D000099252:Fatty Acid Amide Hydrolases; C022203:N-acylethanolamines; C487720:N-cyclohexanecarbonylpentadecylamine; C500528:cyclohexyl carbamic acid 3'-carbamoylbiphenyl-3-yl ester; C046993:N-acylethanolamine amidohydrolase; C078814:anandamide