Increased saturated phospholipid in cultured cells grown with linoleic acid

We found that fetal bovine serum supplementation of culture medium provided limited quantities of linoleic acid, an essential fatty acid, to cells grown in culture (2.8 +/- 0.3% of total fatty acids in 12 lots). Supplementation of the medium with additional linoleic acid resulted in altered phospholipid acyl composition in cells of two established lines, A549, a putative model of the pulmonary Type II epithelial cell, and SIRC, a line derived from rabbit corneal epithelium. In particular, linoleic acid supplementation induced a relative increase in disaturated choline phosphoglycerides of 33 and 36%, respectively, in cells of the two lines. This observation may be relevant to design of media for primary culture of Type II cells, in which disaturated phospholipid synthesis used as an index of differentiated function (surfactant production). Linoleate supplementation did not alter growth or size (protein content) of cells of either line and caused a slight increase in accumulation of neutral lipid, in the form of cytoplasmic droplets, in A549 cells. Supplementation of cell cultures with equivalent concentrations of the nonessential fatty acids palmitic and oleic acid did not significantly alter the growth, morphologic appearance, or lipid composition of the cells. However, it was demonstrated in cells of one line that palmitic acid supplementation temporarily stimulated synthesis of disaturated choline phosphoglyceride from radiolabeled choline.