Macrophages are abundant within adipose tissue depots where they are exposed to fatty acids, leading to lipid accumulation. Herein, we have determined the effects of various fatty acids on the macrophage lipidome. Using targeted mass-spectrometry, we were able to detect 641 individual lipid species in primary murine macrophages treated with a variety of saturated fatty acids and an un-saturated fatty acid, either alone or in combination. The most pronounced effects were observed for the long-chain saturated fatty acid palmitate, which increased the total abundance of numerous classes of lipids. While other medium- and long-chain saturated fatty acids, as well as the long-chain unsaturated fatty acid, had less pronounced effects on the total abundance of specific lipid classes, all fatty acids induced marked alterations in the abundance of numerous lipid species within given lipid classes. Fatty acid treatment markedly altered overall phospholipid saturation status; these effects were most pronounced for phosphatidylcholine and ether-phosphatidylcholine lipid species. Finally, treatment of macrophages with either palmitate or stearate in combination with oleate prevented many of the changes that were observed in macrophages treated with palmitate or stearate alone. Collectively, our results reveal substantial and specific remodelling of the macrophage lipidome following treatment with fatty acids.
Keywords: fatty acids; lipidomics; macrophages; obesity.