Identifying key events from Per- and Polyfluoroalkyl Substances exposure that influence larval zebrafish in light:dark assay using RNA-sequencing analysis of perfluorooctane sulfonic acid (PFOS)

Gene expression data from short-term in vivo studies shows efficacy in quantifying concentration-dependent effects that inform toxicity outcomes, particularly for chemicals with limited toxicity data such as Per- and Polyfluoroalkyl Substances (PFAS). Automated behavioral assessments, at non-teratogenic concentrations reveal perfluorooctane sulfonic acid (PFOS) exposure causes hyperactivity in larval zebrafish (6 days post fertilization (dpf)) during the light phase of the light:dark assay compared to 0.4% dimethylsulfoxide (DMSO) vehicle control. To identify key events that drive this abnormal behavior, zebrafish embryos were exposed to 0.88-2.8 µM PFOS or 0.4% DMSO, and RNA was isolated from pooled head tissue collected at 4 and 5 dpf, before the onset of hyperactivity, for RNA-sequencing (NextSeq 500). Differentially expressed genes (DEGs) were identified using Gene Specific Analysis (Partek Flow, St. Louis, MO) and mapped to human orthologs for pathway analyses to inform mode of action. Overall design: RNA-seq of zebrafish head after exposure to perfluorooctane sulfonic acid at various concentrations or DMSO.