Figure 7.
LDs from brain tissue of DDHD2−/− mice are primarily composed of TAGs. (A) Lipids isolated from the LD fraction from brain tissue of DDHD2−/− mice by a mixture of 4:1:4 (v/v) CHCl3/CH3OH/H2O. Lipid classes were separated by thin layer chromatography (TLC) using an established solvent system46 and visualized by I2 staining. Abbreviations: CE, cholesterol ester; TAG, triacylglycerol; FFA, free fatty acids; DAG, diacylglycerol; Chol, cholesterol; MAG, monoacylglycerol; PL, phospholipid. (B) Estimation of relative lipid quantities in the LD fraction as visualized by I2 staining in panel A. Data respresent average values ± SEM (N = 5). (C) Model to explain how DDHD2 regulates the LD content of neurons. DDHD2 functions as a principal TAG hydrolase in neurons, thereby preventing excessive accumulation of TAGs. Loss of DDHD2, through genetic mutation or chemical inhibition, blocks the metabolism of TAGs, leading to accumulation of TAG-enriched LDs in neurons throughout the CNS.