Cytotoxic Mechanism for Silver Nanoparticles Based High-Content Cellomics and Transcriptome Sequencing

The aim of this study was to investigate the toxic mechanism for differently sized silver nanoparticles (SNPs) on human dermal fibroblasts (HDFs), by combining high content cellomics and transcriptome sequencing. First, the influences of five SNPs (SNP-5, SNP-20, SNP-50, SNP-100, and SNP-200) on O₂, focal adhesion, cytoskeleton and ATP content in HDFs were studied with high content screening and colorimetric method, and the role to cytotoxicity was analysed. Transcriptome sequencing technique was then to filter differentially expressed genes induced by SNPs after 4 h treatment. Key pathways in SNP-induced cytotoxicity were also screened via biological pathway analysis. Furthermore, key genes in HDFs after SNP-induced cytotoxicity were determined through matching analysis with previously obtained important microRNAs and their expression levels were verified with qRT-PCR. Cytological experiments showed that the SNP-5 had the strongest effects on O₂, focal adhesion, cytoskeleton and ATP content, while SNP-20 had the smallest effects. Transcriptome sequencing results showed that 3848, 4213, 2999, 3251 and 5104 genes were found to be differentially expressed in HDFs after treatment with five SNPs. Biological pathway analysis for 1643 uniformly differentially expressed genes revealed that MAPK signaling pathway was the key pathway in SNP-induced cytotoxicity. Two key genes, 1 and 25, which are involved in MAPK signaling pathway were finally identified through matching analysis with important microRNAs and verification. In conclusion, the cytotoxic mechanism for SNPs induced cytotoxicity in HDFs involved SNPs down-regulated expression of 1 and 25 through miR-424-5p in the key MAPK signaling pathway, through blocking of cell cycle, promotion of apoptosis, ultimately leading to cytotoxicity.