Homeostasis of plasmalogens in mammals

Ethanolamine-containing alkenyl ether glycerophospholipid, plasmalogen, is characterized by the presence of vinyl-ether linkage at the sn-1 position. Plasmalogens are found in nearly all mammalian tissues, and important components of cellular membranes. De novo synthesis of plasmalogens initiated in peroxisomes plays a pivotal role in the homeostasis of cellular plasmalogens. Synthesis of plasmalogens is regulated by feedback mechanism via sensing the plasmalogens located in the inner leaflet of plasma membranes, followed by modulating the level of fatty acyl-CoA reductase 1, the enzyme responsible for the synthesis of long-chain alcohols which are essential for the ether-bond formation in peroxisomes. Plasmalogens can be synthesized from alkylglycerol in cells and peripheral tissues such as liver and heart in rodent, whereas plasmalogens essential for the function of brain are more likely supplied by de novo synthesis in brain rather than the transport of peripherally synthesized plasmalogens by crossing blood brain barrier, implying that regulation of plasmalogen synthesis plays an important role in the homeostasis of brain plasmalogens.