Effects of Long-Chain Fatty Acids on Cytosolic Triacylglycerol Accumulation and Lipid Droplet Formation in Primary Cultured Bovine Mammary Epithelial Cells

• Published in: Journal of dairy science Vol. 87; no. 8; pp. 2527 - 2534
• Main Authors: Yonezawa, T, Yonekura, S, Kobayashi, Y, Hagino, A, Katoh, K, Obara, Y
• Format: Journal Article
• Language: English
• Published: Savoy, IL Elsevier Inc 01.08.2004; Am Dairy Sci Assoc; American Dairy Science Association
• Subjects: alphaS1-casein; Animal productions; Animals; Biological and medical sciences; Caseins - genetics; Cattle; CD36 Antigens - genetics; Cells, Cultured; culture media; cytosol; Cytosol - metabolism; dairy cows; differentiation; epithelial cells; Epithelial Cells - drug effects; Epithelial Cells - metabolism; Epithelial Cells - ultrastructure; Fatty Acids - chemistry; Fatty Acids - pharmacology; Female; Food industries; free fatty acids; Fundamental and applied biological sciences. Psychology; gene expression; Gene Expression - drug effects; gene expression regulation; leptin; Leptin - genetics; Linoleic Acid - pharmacology; lipid bodies; lipid droplet; Lipid Metabolism; long chain fatty acids; long-chain fatty acid; mammary glands; Mammary Glands, Animal - drug effects; Mammary Glands, Animal - metabolism; Mammary Glands, Animal - ultrastructure; messenger RNA; Milk and cheese industries. Ice creams; Oleic Acid - pharmacology; Palmitic Acid - pharmacology; receptors; RNA, Messenger - analysis; saturated fatty acids; Stearic Acids - pharmacology; Structure-Activity Relationship; Terrestrial animal productions; triacylglycerol accumulation; Triglycerides - metabolism; unsaturated fatty acids; Vertebrates; lipid droplet; LCFA; long-chain fatty acid; differentiation; bMEC; triacylglycerol accumulation; TAG; MDGI; Bovine; Long chain; Lipids; Droplet; Fatty acids; Vertebrata; Mammalia; Triacylglycerol; Dairy industry; Epithelial cell; Artiodactyla; Mammary gland; Differentiation; Ungulata
• ISSN: 0022-0302; 1525-3198
• DOI: 10.3168/jds.S0022-0302(04)73377-9

Mammary epithelial cells have recently been shown to express and secrete leptin into milk and to accumulate triacylglycerol (TAG) in cytosol. We examined the effects on the accumulation of cytosolic TAG of free fatty acid addition to the medium bathing bovine mammary epithelial cells (bMEC). Both saturated (palmitic and stearic) and unsaturated (oleic and linoleic) fatty acids stimulated the accumulation of TAG in a concentration-dependent manner from 50 to 400μM and the expression of mRNA expression for CD36, which is involved in the uptake and secretion of long-chain fatty acids. However, leptin mRNA expression and lipid droplet formation were significantly increased only by the addition of unsaturated, but not saturated, fatty acids. Interestingly, both types of fatty acids stimulated αs1-casein mRNA expression. These data suggest that the expression of leptin is related to droplet formation, whereas CD36 is related to cytosolic TAG accumulation, and that fatty acids or cytosolic TAG accumulation also have a role to accelerate differentiation of bMEC as shown by casein synthesis.