Alteration of fatty acid composition of LM cells by lipid supplementation and temperature

Abstract

Alteration of the fatty acid composition of monolayer cultures of LM cells grown in chemically defined medium was achieved by supplementation with fatty acids complexed to bovine serum albumin. Phospholipids containing up to 40% linoleate were found in cells grown in medium containing 20 mu g of linoleate/ml. Incorporation of linoleate into phospholipids reached a plateau after 12-24 hr, and cells remained viable for at least 3-4 days. Although linoleic, linolenic, and arachidonic acids were incorporated into LM cells equally well, only the latter was elongated by these cells under these experimental conditions. Nonadecanoic acid was incorporated to a lesser extent than the polyunsaturated fatty acids. Phosphatidylcholine and phosphatidylethanolamine of LM cells had different fatty acid compositions; phosphatidylethanolamine contained more longer chain and unsaturated fatty acids. Cells were also grown in the absence of choline and presence of choline analogs such as N,N-dimethylethanolamine, N-methylethanolamine, 3-amino-1-propanol, and 1-2-amino-1-butanol. The analog phospholipids in these cells had fatty acid compositions which were intermediate between those of phosphatidylethanolamine and phosphatidylcholine of control cells grown in the presence of choline. Linoleate was found in both phosphatidylcholine and phosphatidylethanolamine of cells supplemented with linoleate. The sphingolipid fraction of these cells, however, did not contain significant amounts of linoleate. When linoleate was present in the phospholipids, compensatory decreases in the oleate and palmitoleate content of phospholipids were observed. Lowering of the growth temperature to 28 degrees produced an increase in unsaturate fatty acid content of the phospholipids. When linoleate was supplied to cells grown at 28 degrees, there was no further increase in the unsaturated fatty acid composition of the phospholipids. Using both fatty acid supplementation and lowered growth temperature, LM cell membranes can be produced which have phospholipids with vastly different fatty acid compositions.

Response of endocytosis to altered fatty acyl composition of macrophage phospholipids.

“…The phospholipids of other cultured mammalian cell types have been enriched for saturated or unsaturated fatty acids by various techniques (15)(16)(17), with effects on such membrane properties as concanavalin A binding (18) and lectin-induced cell agglutination (16) which correlated with differences induced in saturated fatty acid content. Similarly, a report concerning nonreceptor-mediated phagocytosis in thioglycollate-stimulated peritoneal macrophages incubated for 4 days in medium containing individual fatty acids appeared during the course of our work and showed reduced particle uptake at 370 (19).…”

Fluorescence lifetime distributions of 1,6-diphenyl-1,3,5-hexatriene reveal the effect of cholesterol on the microheterogeneity of erythrocyte membrane

“…The extraction of lipids from erythrocyte membranes was performed according to Zwaal et al [25]. Neutral lipids and phospholipids were separated by chromatography on short Unisil columns according to Ferguson et al [26]. Multilamellar liposomes were formed from erythrocyte phospholipids by resuspending the extracts in 10 mM Hepes/100 mM KC1 (pH 7.4) and shaking the suspension vigorously.…”

Responses to Interferon of LM Cells Growing Continuously in the Absence of Serum and Exogenous Lipids

“…LM cells have been chosen because of their ability to grow continuously in a simple serum-free medium. This cell line has been widely investigated for studies on the metabolism of lipids (Ferguson et al, 1975;Saito et al, 1977;Schroeder & Vagelos, 1976) and it is derived from the L929 cell line which has been studied extensively for its responses to interferons.…”