title: The stress caused by nitrite with titanium dioxide nanoparticles under UVA irradiation in human keratinocyte cell.
abstract: Our previous work found that in the presence of nitrite, titanium dioxide nanoparticles can cause protein tyrosine nitration under UVA irradiation in vivo. In this paper, the human keratinocyte cells was used as a skin cell model to further study the photo-toxicity of titanium dioxide nanoparticles when nitrite was present. The results showed that nitrite increased the photo-toxicity of titanium dioxide in a dose-dependant manner, and generated protein tyrosine nitration in keratinocyte cells. Morphological study of keratinocyte cells suggested a specific apoptosis mediated by apoptosis inducing factor. It was also found the main target nitrated in cells was cystatin-A, which expressed abundantly in cytoplasm and functioned as a cysteine protease inhibitor. The stress induced by titanium dioxide with nitrite under UVA irradiation in human keratinocyte cells appeared to trigger the apoptosis inducing factor mediated cell death and lose the inhibition of active caspase by cystatin-A. We conclude that nitrite can bring new damage and stress to human keratinocyte cells with titanium dioxide nanoparticles under UVA irradiation.
authors.affiliation: School of Chemistry and Chemical Engineering, Huazhong University of Science & Technology, 1037 Luoyu Road, Wuhan 430074, People's Republic of China.
authors.forename: Min
authors.initials: M
authors.lastname: Tu
authors.forename: Yi
authors.initials: Y
authors.lastname: Huang
authors.forename: Hai-Ling
authors.initials: HL
authors.lastname: Li
authors.forename: Zhong-Hong
authors.initials: ZH
authors.lastname: Gao
mesh_terms: D017209:Apoptosis / Q000187:drug effects; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D055312:Cystatin A / Q000378:metabolism; D017484:Dermatitis, Phototoxic; D006801:Humans; D015603:Keratinocytes / Q000187:drug effects* / Q000378:metabolism; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles / Q000633:toxicity* / Q000648:ultrastructure; D009573:Nitrites / Q000378:metabolism*; D018384:Oxidative Stress / Q000187:drug effects* / Q000528:radiation effects; D012867:Skin / Q000187:drug effects* / Q000378:metabolism; D053719:Tandem Mass Spectrometry; D014025:Titanium / Q000633:toxicity*; D014443:Tyrosine / Q000378:metabolism
chemical_list: D055312:Cystatin A; D009573:Nitrites; C009495:titanium dioxide; D014443:Tyrosine; C026407:CSTA protein, human; D014025:Titanium