LPAAT3 incorporates docosahexaenoic acid into skeletal muscle cell membranes and is upregulated by PPARδ activation.
Adaption of skeletal muscle to endurance exercise includes PPARδ- and AMP-activated protein kinase (AMPK)/PPARγ coactivator 1α-mediated transcriptional responses that result in increased oxidative capacity and conversion of glycolytic to more oxidative fiber types. These changes are associated with whole-body metabolic alterations including improved glucose handling and resistance to obesity. Increased DHA (22:6n-3) content in phosphatidylcholine (PC) and phosphatidylethanolamine (PE) is also reported in endurance exercise-trained glycolytic muscle; however, the DHA-metabolizing enzymes involved and the biological significance of the enhanced DHA content are unknown. In the present study, we identified lysophosphatidic acid acyltransferase (LPAAT)3 as an enzyme that was upregulated in myoblasts during in vitro differentiation and selectively incorporated DHA into PC and PE. LPAAT3 expression was increased by pharmacological activators of PPARδ or AMPK, and combination treatment led to further increased LPAAT3 expression and enhanced incorporation of DHA into PC and PE. Our results indicate that LPAAT3 was upregulated by exercise-induced signaling pathways and suggest that LPAAT3 may also contribute to the enhanced phospholipid-DHA content of endurance-trained muscles. Identification of DHA-metabolizing enzymes in the skeletal muscle will help to elucidate broad metabolic effects of DHA.
['Valentine|William J|WJ|', 'Tokuoka|Suzumi M|SM|', 'Hishikawa|Daisuke|D|', 'Kita|Yoshihiro|Y|', 'Shindou|Hideo|H|', 'Shimizu|Takao|T|']
D000217:Acyltransferases D000818:Animals D002462:Cell Membrane D002478:Cells, Cultured D004281:Docosahexaenoic Acids D051379:Mice D018482:Muscle, Skeletal D047494:PPAR delta D015854:Up-Regulation
exercise fatty acid/metabolism lipidomics lysophosphatidic acid acyltransferase 3 mass spectrometry, 1-acylglycerol-3-phosphate O-acyltransferase omega-3 fatty acids