Long-chain acyl-CoA synthetase 4 participates in the formation of highly unsaturated fatty acid-containing phospholipids in murine macrophages

• Published in: Biochimica et biophysica acta. Molecular and cell biology of lipids 2019-11, Vol.1864 (11), p.1606-1618
• Main Authors: Kuwata, Hiroshi, Nakatani, Eriko, Shimbara-Matsubayashi, Satoko, Ishikawa, Fumihiro, Shibanuma, Motoko, Sasaki, Yuka, Yoda, Emiko, Nakatani, Yoshihito, Hara, Shuntaro
• Format: Article
• Language: English
• Subjects: Acyl-CoA; Animals; Arachidonic Acid - metabolism; Cells, Cultured; Coenzyme A Ligases - genetics; Coenzyme A Ligases - metabolism; Eicosanoid; Fatty Acids, Unsaturated - metabolism; Female; Glycerophospholipid; Long-chain acyl-CoA synthetase 4; Macrophages - metabolism; Mice; Mice, Knockout; Phagocytosis; Phospholipids - metabolism; Polyunsaturated fatty acid; Substrate Specificity
• ISSN: 1388-1981; 1879-2618
• DOI: 10.1016/j.bbalip.2019.07.013

Long-chain acyl-coenzyme A synthetases (ACSLs) are a family of enzymes that convert free long-chain fatty acids into their acyl-coenzyme A (CoA) forms. ACSL4, belonging to the ACSL family, shows a preferential use of arachidonic acid (AA) as its substrate and plays a role in the remodeling of AA-containing phospholipids by incorporating free AA. However, little is known about the roles of ACSL4 in inflammatory responses. Here, we assessed the roles of ACSL4 on the effector functions of bone marrow-derived macrophages (BMDMs) obtained from mice lacking ACSL4. Liquid chromatography–tandem mass spectrometry analysis revealed that various highly unsaturated fatty acid (HUFA)-derived fatty acyl-CoA species were markedly decreased in the BMDMs obtained from ACSL4-deficient mice compared with those in the BMDMs obtained from wild-type mice. BMDMs from ACSL4-deficient mice also showed a reduced incorporation of HUFA into phosphatidylcholines. The stimulation of BMDMs with lipopolysaccharide (LPS) elicited the release of prostaglandins (PGs), such as PGE2, PGD2 and PGF2α, and the production of these mediators was significantly enhanced by ACSL4 deficiency. In contrast, neither the LPS-induced release of cytokines, such as IL-6 and IL-10, nor the endocytosis of zymosan or dextran was affected by ACSL4 deficiency. These results suggest that ACSL4 has a crucial role in the maintenance of HUFA composition of certain phospholipid species and in the incorporation of free AA into the phospholipids in LPS-stimulated macrophages. ACSL4 dysfunction may facilitate inflammatory responses by an enhanced eicosanoid storm. •ACSL4 uses AA, EPA, adrenic acid, or DHA, as good substrates.•ACSL4-deficiency decreases the levels of PUFA-derived acyl-CoA in BMDMs.•High levels of PUFAs are observed in the culture medium of ACSL4 KO BMDMs.•ACSL4 enzyme competes with the COX enzymes for AA.•ACSL4 deficiency leads to substrate shunting towards PG production in BMDMs.