[Proteomic study on HaCaT cell membrane proteins after exposed to silica nanomaterials]

To identify the differential expression of membrane proteins after HaCaT cell was treated with 15 nm silica nanomaterials (SiO2).

The HaCaT cells were cultured for 24 h under 15 nm SiO2 in various concentrations (2. 5, 5. 0, 10. 0 mg/L), and ddH2O were used as control. The cell viability were measured with CCK-8 assay. The membrane proteins of SiO2-treated group (10. 0 mg/L) and controls were extracted by ProteoExtract subcellular proteome extraction kit. The differentially expressed membrane proteins were analyzed by a two-dimensional fluorescence difference gel electrophoresis (2D-DIGE) and matrix-assisted laser desorption/ionization tandem time-of-flight mass spectrometry (MALDI-TOF-MS). Bioinformatics analysis was used to reveal the biological functions and predict transmembrane domains of differential expressed proteins. The expression of differential membrane proteins were measured by Western blot analysis.

The cell viability was significantly decreased with the increases of 15 nm SiO2 exposure levels. After treatment with 2. 5, 5. 0, 10. 0 mg/L of 15nm SiO2, the cell viability was assessed to (91. 3% ± 6. 1%), (81. 7% ± 7. 0%) and (74. 0% ± 2. 6%) of control level (P < 0. 05), respectively. In the proteomic analysis, a total of 10 proteins were identified as differential expression in the SiO2-treated simples compared with controls. Among these, 7 of these proteins were predicted as membrane proteins with at least one significant transmembrane domain. The most dominant function that the identified proteins involved in was binding and structural molecule activity. The differential expression of G protein-coupled receptor 179 (GPR 179) and L-plastin (LCP1) were verified by Western-blot analysis under 15nm SiO2 exposure in various concentrations.

The exposure of 15 nm SiO2 can significantly reduce the cell proliferation and induce a down-regulation of membrane protein expression in HaCaT cells.