Dysregulation of Macrophage Activation Profiles by Engineered Nanoparticles. Mus musculus

To investigate how the phenotype of macrophages that have engulfed engineered nanoparticles (ENPs) differs from normal macrophages, we conducted Affymetrix microarray studies to identify the gene regulatory pathways affected by the ENPs. To mimic potential occupational exposure scenarios, the experimental design involved pretreatment of mouse primary bone marrow macrophages with the ENPs (25 mg/ml) for 24 hr, followed by removal of residual ENPs and challenging the macrophages with the TLR4 ligand and surrogate bacterial stimulus, lipopolysachharide (LPS) for 4 hr. The 4 hr challenge time was chosen based on preliminary studies which showed many of the proinflammatory gene expression responses peak between 2-6 hr after LPS treatment. Transcriptional responses were measured by global microarray analysis of mouse primary bone marrow macrophage cells. Overall design: Groups (N=3 replicates) of primary mouse bone marrow macrophages were pretreated with selected engineered nanoparticless (33 nm iron oxide(SPIO) or 50 nm amorphous silica) at concentrations of 25 mg/ml for 24 hours. After removing the nanoparticles, macrophages were challenged with fresh media containing 10ng/ml lipopolysaccharide (LPS).