Lipid droplets: their role in nanoparticle-induced oxidative stress.
Lipid droplets are cytoplasmic organelles found in almost all cells under physiological or pathological conditions. Certain nanoparticles can induce lipid droplet formation under oxidative stress conditions. Small metallic nanoparticles such as cadmium telluride (CdTe) nanoparticles, particularly those with incompletely protected surfaces, induce oxidative stress and may inflict damages to several intracellular organelles. The objective of this study was to assess formation of lipid droplets in cells treated with CdTe nanoparticles and relate their status to cell function (mitochondrial activity and cell viability). Multicolor labeling of cellular organelles (lipid droplets and lysosomes) showed that lipid droplets formed in pheochromocytoma (PC12) cells following nanoparticle or oleic acid treatment. Some lipid droplets were found closely apposed to lysosomes suggesting possible communication between these organelles during severe oxidative stress. Combination of microscopy of living cells with cell viability assays showed that oleic acid-induced lipid droplets not only serve as intracellular lipid storage sites but also play a protective role in starving stressed cells. Results from these studies suggest that oleic acid-induced LD in PC12 cells are dynamic and adaptive organelles, which provide energy to starving cells and facilitate their rescue under starvation and exposure to metallic nanoparticles.
Khatchadourian
Armen
A
Department of Pharmacology and Therapeutics, McGill University, 3655 Promenade Sir William Osler, Montreal, Quebec, Canada H3G 1Y6.
Maysinger
Dusica
D
D000818:Animals; D019187:Cadmium Compounds / Q000494:pharmacology*; D002470:Cell Survival / Q000187:drug effects; D050356:Lipid Metabolism; D008247:Lysosomes / Q000187:drug effects / Q000378:metabolism; D053768:Metal Nanoparticles; D008928:Mitochondria / Q000187:drug effects; D009829:Oleic Acids / Q000494:pharmacology*; D018384:Oxidative Stress / Q000187:drug effects*; D016716:PC12 Cells / Q000187:drug effects / Q000378:metabolism; D010169:Palmitic Acids / Q000494:pharmacology*; D010588:Phagosomes / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D017382:Reactive Oxygen Species / Q000378:metabolism; D013691:Tellurium / Q000494:pharmacology*
D019187:Cadmium Compounds; D009829:Oleic Acids; D010169:Palmitic Acids; D017382:Reactive Oxygen Species; D013691:Tellurium; C028337:cadmium telluride