Effect of manipulation of phospholipid polar head group on low density lipoprotein metabolism in human cultured fibroblasts.

Modification of phospholipid polar head group was achieved by growing human cultured fibroblasts in medium devoid of serum and supplemented with N-methyl ethanolamine or N,N-dimethylethanolamine during 48 h. The corresponding phospholipids accounted for approximately 45% of total phospholipids. Whereas low density lipoprotein (LDL) binding was unaffected, LDL internalization and degradation appeared to be markedly reduced in the presence of N-methylethanolamine. N,N-dimethylethanolamine had no effect on the three studied parameters. These results emphasize the importance of phospholipid polar head group in LDL processing by receptor-mediated endocytosis.