Lipid Extraction

Lipids were extracted based on the Bligh-Dyer method unless otherwise stated^22–23. In brief, for extraction from cells, the cell pellet was re-suspended in PBS, followed by addition of methanol and chloroform to make 1:1:2 PBS:methanol:chloroform solvent (v/v/v). The mixture was shaken vigorously for 30 s, vortexed for 15 s. For extraction from tissues, the sample was Dounce homogenized in 1:1:2 PBS:methanol:chloroform solvent on ice. An appropriate amount of internal standards were added to chloroform prior to extraction as indicated in each experiment. The resulted homogenate was centrifuged at 2200 g for 6 min at 4 °C. The bottom organic layer was collected and dried under a gentle stream of nitrogen.