MicroRNA sequencing and molecular mechanisms analysis of the effects of gold nanoparticles on human dermal fibroblasts

The aim of this study is to investigate the mechanism of the effects of gold nanoparticles (GNPs) on human dermal fibroblasts (HDFs) at the microRNA level. First, 20-nm GNPs were synthesized and their effect on HDF proliferation was assayed. SOLiD sequencing technology was then utilized to obtain the microRNA expression profile after GNP treatment. The microRNA expression data were compared with previously obtained mRNA and protein expression data to identify the microRNA target mRNAs/proteins. Moreover, bioinformatics analyses and validation experiments were conducted. Lastly, the roles of GNPs and silver nanoparticle (SNPs) on HDFs were compared at the microRNA level. The results showed that GNPs were not cytotoxic as 202 microRNAs were differentially expressed after treatment with 200 μm GNPs for 1, 4 and 8 h. Bioinformatics analyses revealed that these dysregulated miRNAs mainly functioned in metabolic processes and participated in 71 biological pathways, including two key pathways in which the differentially expressed miRNA, target mRNAs and proteins were simultaneously joined, the mRNA processing pathway and MAPK signaling pathway. Biological experiments in cells confirmed that GNPs affected energy metabolism but did not induce apoptosis, destroy the cytoskeleton or induce reactive oxygen species (ROS) production. Comparing the mechanism of the effects of GNPs and SNPs on HDFs at the microRNA level, it was found that, unlike SNPs, GNPs impacted the cell cycle, weakened the ATP synthesis inhibition and cytoskeleton damage, suppressed apoptosis, and did not lead to cytotoxicity. The difference in ROS production by these two nanoparticles might partially explain the fact that GNPs showed no cytotoxic effects on HDFs, unlike SNPs.