title: Indirect effects of TiO2 nanoparticle on neuron-glial cell interactions.
abstract: Although, titanium dioxide nanoparticles (TiO2NPs) are nanomaterials commonly used in consumer products, little is known about their hazardous effects, especially on central nervous systems. To examine this issue, ALT astrocyte-like, BV-2 microglia and differentiated N2a neuroblastoma cells were exposed to 6 nm of 100% anatase TiO2NPs. A lipopolysaccharide (LPS) was pre-treated to activate glial cells before NP treatment for mimicking NP exposure under brain injury. We found that ALT and BV-2 cells took up more NPs than N2a cells and caused lower cell viability. TiO2NPs induced IL-1β in the three cell lines and IL-6 in N2a. LPS-activated BV-2 took up more TiO2NPs than normal BV-2 and released more intra/extracellular reactive oxygen species (ROS), IL-1β, IL-6 and MCP-1 than did activated BV-2. Involvement of clathrin- and caveolae-dependent endocytosis in ALT and clathrin-dependent endocytosis and phagocytosis in BV-2 both had a slow NP translocation rate to lysosome, which may cause slow ROS production (after 24 h). Although TiO2NPs did not directly cause N2a viability loss, by indirect NP exposure to the bottom chamber of LPS-activated BV-2 in the Transwell system, they caused late apoptosis and loss of cell viability in the upper N2a chamber due to H2O2 and/or TNF-α release from BV-2. However, none of the adverse effects in N2a or BV-2 cells was observed when TiO2NPs were exposed to ALT-N2a or ALT-BV-2 co-culture. These results demonstrate that neuron damage can result from TiO2NP-mediated ROS and/or cytokines release from microglia, but not from astrocytes.
authors.affiliation: Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, No. 101, Section 2, Kuang-Fu Road, Hsinchu 30013, Taiwan. Electronic address: ilunshiou@gmail.com.
authors.forename: I-Lun
authors.initials: IL
authors.lastname: Hsiao
authors.affiliation: Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, No. 101, Section 2, Kuang-Fu Road, Hsinchu 30013, Taiwan. Electronic address: a03039595@hotmail.com.
authors.forename: Chia-Cheng
authors.initials: CC
authors.lastname: Chang
authors.affiliation: Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, No. 101, Section 2, Kuang-Fu Road, Hsinchu 30013, Taiwan. Electronic address: s9812805@m98.nthu.edu.tw.
authors.forename: Chung-Yi
authors.initials: CY
authors.lastname: Wu
authors.affiliation: Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, No. 101, Section 2, Kuang-Fu Road, Hsinchu 30013, Taiwan. Electronic address: d944530@oz.nthu.edu.tw.
authors.forename: Yi-Kong
authors.initials: YK
authors.lastname: Hsieh
authors.affiliation: Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, No. 101, Section 2, Kuang-Fu Road, Hsinchu 30013, Taiwan. Electronic address: cychuang@mx.nthu.edu.tw.
authors.forename: Chun-Yu
authors.initials: CY
authors.lastname: Chuang
authors.affiliation: Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, No. 101, Section 2, Kuang-Fu Road, Hsinchu 30013, Taiwan. Electronic address: cfwang@mx.nthu.edu.tw.
authors.forename: Chu-Fang
authors.initials: CF
authors.lastname: Wang
authors.affiliation: Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, No. 101, Section 2, Kuang-Fu Road, Hsinchu 30013, Taiwan. Electronic address: yjhuang@mx.nthu.edu.tw.
authors.forename: Yuh-Jeen
authors.initials: YJ
authors.lastname: Huang
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D001253:Astrocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D002450:Cell Communication / Q000187:drug effects*; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D018920:Coculture Techniques; D004705:Endocytosis / Q000187:drug effects; D006861:Hydrogen Peroxide / Q000378:metabolism; D008070:Lipopolysaccharides / Q000633:toxicity; D008247:Lysosomes / Q000378:metabolism; D053768:Metal Nanoparticles / Q000737:chemistry / Q000633:toxicity*; D051379:Mice; D017628:Microglia / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism; D010587:Phagocytosis / Q000187:drug effects; D017382:Reactive Oxygen Species / Q000378:metabolism; D014025:Titanium / Q000737:chemistry*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: D008070:Lipopolysaccharides; D017382:Reactive Oxygen Species; D014409:Tumor Necrosis Factor-alpha; C009495:titanium dioxide; D009569:Nitric Oxide; D006861:Hydrogen Peroxide; D014025:Titanium
keywords: Central nervous system; Co-culture; Cytokines; Reactive oxygen species; Titanium dioxide nanoparticles; Uptake mechanisms