title: Mitochondrial Toxicity of Cadmium Telluride Quantum Dot Nanoparticles in Mammalian Hepatocytes.
abstract: There are an increasing number of studies indicating that mitochondria are relevant targets in nanomaterial-induced toxicity. However, the underlying mechanisms by which nanoparticles (NPs) interact with these organelles and affect their functions are unknown. The aim of this study was to investigate the effects of cadmium telluride quantum dot (CdTe-QD) NPs on mitochondria in human hepatocellular carcinoma HepG2 cells. CdTe-QD treatment resulted in the enlargement of mitochondria as examined with transmission electron microscopy and confocal microscopy. CdTe-QDs appeared to associate with the isolated mitochondria as detected by their inherent fluorescence. Further analyses revealed that CdTe-QD caused disruption of mitochondrial membrane potential, increased intracellular calcium levels, impaired cellular respiration, and decreased adenosine triphosphate synthesis. The effects of CdTe-QDs on mitochondrial oxidative phosphorylation were evidenced by changes in levels and activities of the enzymes of the electron transport chain. Elevation of peroxisome proliferator-activated receptor-γ coactivator levels after CdTe-QD treatment suggested the effects of CdTe-QDs on mitochondrial biogenesis. Our results also showed that the effects of CdTe-QDs were similar or greater to those of cadmium chloride at equivalent concentrations of cadmium, suggesting that the toxic effects of CdTe-QDs were not solely due to cadmium released from the NPs. Overall, the study demonstrated that CdTe-QDs induced multifarious toxicity by causing changes in mitochondrial morphology and structure, as well as impairing their function and stimulating their biogenesis.
authors: *Biotechnology Laboratory, Mechanistic Studies Division, Environmental Health Science Research Bureau, HECSB, Health Canada, Ottawa, Ontario, Canada K1A 0K9, Department of Biology and Institute of Biochemistry, Carleton University, Ottawa, Ontario, Canada K1S 5B6 and The University of Ottawa, Heart Institute, Ottawa, Ontario, Canada K1Y 4W7 *Biotechnology Laboratory, Mechanistic Studies Division, Environmental Health Science Research Bureau, HECSB, Health Canada, Ottawa, Ontario, Canada K1A 0K9, Department of Biology and Institute of Biochemistry, Carleton University, Ottawa, Ontario, Canada K1S 5B6 and The University of Ottawa, Heart Institute, Ottawa, Ontario, Canada K1Y 4W7.
authors: Kathy C
authors: KC
authors: Nguyen
authors: *Biotechnology Laboratory, Mechanistic Studies Division, Environmental Health Science Research Bureau, HECSB, Health Canada, Ottawa, Ontario, Canada K1A 0K9, Department of Biology and Institute of Biochemistry, Carleton University, Ottawa, Ontario, Canada K1S 5B6 and The University of Ottawa, Heart Institute, Ottawa, Ontario, Canada K1Y 4W7.
authors: Peter
authors: P
authors: Rippstein
authors: *Biotechnology Laboratory, Mechanistic Studies Division, Environmental Health Science Research Bureau, HECSB, Health Canada, Ottawa, Ontario, Canada K1A 0K9, Department of Biology and Institute of Biochemistry, Carleton University, Ottawa, Ontario, Canada K1S 5B6 and The University of Ottawa, Heart Institute, Ottawa, Ontario, Canada K1Y 4W7.
authors: Azam F
authors: AF
authors: Tayabali
authors: *Biotechnology Laboratory, Mechanistic Studies Division, Environmental Health Science Research Bureau, HECSB, Health Canada, Ottawa, Ontario, Canada K1A 0K9, Department of Biology and Institute of Biochemistry, Carleton University, Ottawa, Ontario, Canada K1S 5B6 and The University of Ottawa, Heart Institute, Ottawa, Ontario, Canada K1Y 4W7 bill_willmore@carleton.ca.
authors: William G
authors: WG
authors: Willmore
mesh_terms: D019187:Cadmium Compounds / Q000633:toxicity*; D056945:Hep G2 Cells; D022781:Hepatocytes / Q000187:drug effects*; D006801:Humans; D046529:Microscopy, Electron, Transmission; D008928:Mitochondria / Q000187:drug effects*; D053758:Nanoparticles; D045663:Quantum Dots; D013691:Tellurium / Q000633:toxicity*
chemical_list: D019187:Cadmium Compounds; D013691:Tellurium; C028337:cadmium telluride
keywords: cadmium telluride quantum dots; cellular respiration; electron transport chain; hepatocytes; membrane potential; mitochondria