Proteomics study of the cellular function in response to nanomaterials.
Date of Issue2012
School of Chemical and Biomedical Engineering
Because of their attractive chemical and physical properties, graphitic nanomaterials and their derivatives have gained tremendous interest for applications in electronics, materials and biomedical areas. However, few detailed studies have been performed to evaluate the potential cytotoxicity of these nanomaterials on the living systems at the molecular level. In the present study, our group exploited the iTRAQ-coupled 2D LC-MS/MS approach with the purpose of characterizing the cellular functions in response to these nanomaterials at the proteome level. Specifically, single-walled carbon nanotubes (SWCNTs), graphene, as well as their derivatives such as oxidized SWCNTs and graphene oxide (GO) were tested, while the human hepatoma HepG2 cells were used as the in vitro model to study the potential cytotoxicity of these nanomaterials on the vital organ of liver. Differentially expressed proteins involved in metabolic pathway, redox regulation, cytoskeleton formation and cell growth were sucessfully identified through the iTRAQ-coupled 2D LC-MS/MS approach. Based on the protein profile, we found both SWCNTs and oxidized SWCNTs induced oxidative stress and interfered the intracellular metabolic routes, protein synthesis and cytoskeletal systems. However, only moderate variation of protein levels for the cells treated with graphene and GO was observed. Further functional assays such as cell proliferation assay, Western blotting analysis, apoptosis assay and cell cycle anlysis were carried out to confirm the data obtained from protein profile. We found oxidized SWCNTs did trigger elevated level of reactive oxygen species (ROS), perturb the cell cycle and result in a significant increase in the proportion of apoptotic cells. In contrast, these functional assays indicated there was no significant increase in the percentage of apoptotic cells and cell cycle was not severely perturbed after exposed to GO.