title: Copper nanoclusters trigger muscle cell apoptosis and atrophy in vitro and in vivo.
abstract: Copper nanoclusters (CuNCs) are increasingly being used in nanomedicine owing to their utility in cellular imaging and as catalysts. Additionally, nanotoxicology research of CuNCs is gaining attention. We report here the synthesis and characterization of CuNCs and their cytotoxic impact on muscle cells. A simple protein-directed synthesis of stable CuNCs was prepared, using bovine serum albumin as the stabling agent. Physicochemical characterization of the synthesized CuNCs was performed using transmission electron microscopy. To evaluate the in vitro cytotoxicity, C2C12 cells were exposed to increasing doses (from 0.1 to 50 µg ml(-1)) of CuNCs. CuNCs affected the viability of C2C12 cells in a dose-dependent manner, as detected by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and a lactate dehydrogenase release assay. Further studies indicated that CuNCs induced the formation of reactive oxygen species and decreased the activities of catalase and glutathione. CuNC treatment decreased the mitochondrial membrane potential and induced apoptosis, accompanied by an increase in the protein expression ratio of Bax/Bcl-2 and caspase-3/9 activity in C2C12 cells. CuNCs treatment resulted in atrophy of the C2C12 myotubes, which was characterized by the increased expression of atrophy-related genes, such as atrogin-1 and MuRF1. Finally, CuNCs induce morphological atrophy of primary muscle cells and mouse gastrocnemius muscle. Taken together, these results suggest that exposure to CuNCs may be a risk factor for the skeletal muscle system.
authors.affiliation: Hubei Province Key Laboratory of Biotechnology of Chinese Traditional Medicine, Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, Hubei University, Wuhan, 430062, China.
authors.forename: Yayun
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Hubei Province Key Laboratory of Biotechnology of Chinese Traditional Medicine, Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, Hubei University, Wuhan, 430062, China.
authors.forename: Jichao
authors.initials: J
authors.lastname: Liang
authors.affiliation: Hubei Province Key Laboratory of Biotechnology of Chinese Traditional Medicine, Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, Hubei University, Wuhan, 430062, China.
authors.forename: Qiuju
authors.initials: Q
authors.lastname: Wang
authors.affiliation: Ministry of Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules, Hubei University, Wuhan, 430062, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: He
authors.affiliation: Hubei Province Key Laboratory of Biotechnology of Chinese Traditional Medicine, Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, Hubei University, Wuhan, 430062, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Chen
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D051017:Apoptosis Regulatory Proteins / Q000235:genetics / Q000378:metabolism; D002374:Catalase / Q000378:metabolism; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D019327:Copper Sulfate / Q000737:chemistry / Q000633:toxicity*; D004305:Dose-Response Relationship, Drug; D005786:Gene Expression Regulation; D005978:Glutathione / Q000378:metabolism; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008297:Male; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D053768:Metal Nanoparticles / Q000737:chemistry / Q000633:toxicity*; D051379:Mice; D008810:Mice, Inbred C57BL; D046529:Microscopy, Electron, Transmission; D008931:Mitochondria, Muscle / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D018485:Muscle Fibers, Skeletal / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D009133:Muscular Atrophy / Q000139:chemically induced* / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D018384:Oxidative Stress / Q000187:drug effects; D010766:Phosphorylation; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D013499:Surface Properties; D013997:Time Factors
chemical_list: D051017:Apoptosis Regulatory Proteins; D017382:Reactive Oxygen Species; D007770:L-Lactate Dehydrogenase; D002374:Catalase; D051057:Proto-Oncogene Proteins c-akt; D046988:Proteasome Endopeptidase Complex; D005978:Glutathione; D019327:Copper Sulfate
keywords: C2C12 cells; atrophy; copper nanoclusters; cytotoxicity; nanotoxicity