title: [The role of caveolin-1 for carbon black nanoparticles uptake in vitro].
abstract: OBJECTIVE
  To investigate the protein expression of caveolin-1 in type II alveolar epithelial cells (A549) exposed to carbon black nanoparticles (CB NPs) and the role of caveolin in the endocytosis of CB NPs.
  
  
  METHODS
  A549 cells were exposed to 0, 25, 50, 100, 200, and 400 µg/ml CB NPs for 24 h; then, trypan blue assay was applied to determine the cell viability. A549 cells were also exposed to 0, 25, 50, and 100 µg/ml CB NPs for 24 h, then, transmission electron microscopy (TEM) and flow cytometry were applied to observe the morphological change of cells and cellular side scatter (SSC), and Western blot was used to analyze the effect of CB NPs on the protein expression of caveolin-1. A549 cells were co-exposed to1 µg/ml filipin and 100 µg/ml CB NPs for 24 h, then, the cellular SSC was observed.
  
  
  RESULTS
  Compared with controls, the A549 cells exposed to 200 and 400 µg/ml CB NPs had the cell viability decreased by 38.2% and 46.6%, respectively (P < 0.05), while those exposed to 25, 50, and 100 µg/ml CB NPs showed no significant decrease in cell vitality (P > 0.05). The protein expression of caveolin-1 was significantly higher in the cells exposed to 50 and 100 µg/ml CB NPs than in controls (P < 0.05). The TEM showed that plasmalemmal vesicles containing black particles were found in the cytoplasm of the cells exposed to 50 and 100 µg/ml CB NPs. The flow cytometry showed that the cellular SSC ratio increased from 1.007 to 1.331 as the dose of CB NPs rose within 0 ∼ 100 µg/ml and fell to 1.25 after the cells were co-exposed to1 µg/ml filipin and 100 µg/ml CB NPs.
  
  
  CONCLUSIONS
  Carbon black nanoparticles can be transferred into A549 cells by endocytosis, but caveolin-mediated endocytic pathway plays a minor role in this process.
authors.affiliation: Institute of hygiene, Zhejiang Academy of Medical Sciences, Hangzhou, China.
authors.forename: Min
authors.initials: M
authors.lastname: Yu
authors.forename: Ri-ping
authors.initials: RP
authors.lastname: Chen
authors.forename: Zheng-yu
authors.initials: ZY
authors.lastname: Jia
authors.forename: Jun-qiang
authors.initials: JQ
authors.lastname: Chen
authors.forename: Zhao-qiang
authors.initials: ZQ
authors.lastname: Jiang
authors.forename: Lin-fang
authors.initials: LF
authors.lastname: Feng
authors.forename: Xing
authors.initials: X
authors.lastname: Zhang
mesh_terms: D051242:Caveolin 1 / Q000502:physiology*; D002460:Cell Line; D004705:Endocytosis; D006801:Humans; D053758:Nanoparticles; D053260:Soot / Q000493:pharmacokinetics*
chemical_list: C495540:CAV1 protein, human; D051242:Caveolin 1; D053260:Soot