Formation of N-acyl-phosphatidylethanolamines by cytosolic phospholipase A2ε in an ex vivo murine model of brain ischemia

• Published in: Biochimica et biophysica acta. Molecular and cell biology of lipids Vol. 1867; no. 12; p. 159222
• Main Authors: Rahman, S.M. Khaledur, Hussain, Zahir, Morito, Katsuya, Takahashi, Naoko, Sikder, Mohammad Mamun, Tanaka, Tamotsu, Ohta, Ken-ichi, Ueno, Masaki, Takahashi, Hiroo, Yamamoto, Tohru, Murakami, Makoto, Uyama, Toru, Ueda, Natsuo
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.12.2022
• Subjects: Brain ischemia; Endocannabinoid; N-acyl-phosphatidylethanolamine; N-acylethanolamine; N-acyltransferase; Phospholipase A2; DHEA; MPC; FAAH; PS; DTT; N-acyl-phosphatidylethanolamine; TLC; NAPE; LC-MS/MS; Endocannabinoid; NAPE-PLD; qPCR; AEA; WT; PSC; Phospholipase A2; CRISPR/Cas9; PLA2G4E; N-acyltransferase; OEA; N-acylethanolamine; PEA; PLAAT; NAE; PC; PE; Brain ischemia; GAPDH; PCR; cPLA2ε
• ISSN: 1388-1981; 1879-2618
• DOI: 10.1016/j.bbalip.2022.159222

N-Acyl-phosphatidylethanolamines (NAPEs), a minor class of membrane glycerophospholipids, accumulate along with their bioactive metabolites, N-acylethanolamines (NAEs) during ischemia. NAPEs can be formed through N-acylation of phosphatidylethanolamine by cytosolic phospholipase A2ε (cPLA2ε, also known as PLA2G4E) or members of the phospholipase A and acyltransferase (PLAAT) family. However, the enzyme responsible for the NAPE production in brain ischemia has not yet been clarified. Here, we investigated a possible role of cPLA2ε using cPLA2ε-deficient (Pla2g4e−/−) mice. As analyzed with brain homogenates of wild-type mice, the age dependency of Ca2+-dependent NAPE-forming activity showed a bell-shape pattern being the highest at the first week of postnatal life, and the activity was completely abolished in Pla2g4e−/− mice. However, liquid chromatography-tandem mass spectrometry revealed that the NAPE levels of normal brain were similar between wild-type and Pla2g4e−/− mice. In contrast, post-mortal accumulations of NAPEs and most species of NAEs were only observed in decapitated brains of wild-type mice. These results suggested that cPLA2ε is responsible for Ca2+-dependent formation of NAPEs in the brain as well as the accumulation of NAPEs and NAEs during ischemia, while other enzyme(s) appeared to be involved in the maintenance of basal NAPE levels. •cPLA2ε-knockout mice lack Ca2+-dependent N-acyl-PE (NAPE)-forming ability in brain.•Expression levels of cPLA2ε in the brain are highest in the first week since birth.•Postmortem accumulation of brain NAPEs and N-acylethanolamines depends on cPLA2ε.•Enzymes other than cPLA2ε may be involved in the maintenance of basal NAPE levels.