Influence of chemical dose and exposure duration on protein synthesis in green sea turtle primary cells.

Understanding the impacts of chemical exposure in marine wildlife is challenging, due to practical and ethical constraints that preclude traditional toxicology research on these animals. This study addressed some of these limitations by presenting an ethical and high throughput cell-based approach to elucidate molecular-level effects of contaminants on sea turtles. The experimental design addressed basic questions of cell-based toxicology, including chemical dose and exposure time. Primary green turtle skin cells were exposed to polychlorinated biphenyl (PCB) 153 and perfluorononanoic acid (PFNA) for 24 and 48 h, at three sub-lethal, environmentally relevant concentrations (1, 10 and 100 μg/L). Sequential window acquisition of all theoretical mass spectra (SWATH-MS) identified over 1000 differentially abundant proteins within the 1% false discovery rate (FDR) threshold. The 24 h exposure resulted in a greater number of differentially abundant proteins, compared to 48 h exposure, for both contaminants. However, there were no statistically significant dose-response relationships for the number of differentially synthesised proteins, nor differences in the proportion of increased vs decreased proteins between or within exposure times. Known in vivo markers of contaminant exposure, superoxide dismutase and glutathione S-transferase, were differentially abundant following exposure to PCB153 and PFNA. SIGNIFICANCE: Cell-based (in vitro) proteomics provides an ethical and high throughput approach to understanding the impacts of chemical contamination on sea turtles. Through investigating effects of chemical dose and exposure duration on unique protein abundance in vitro, this study provides an optimised framework for conducting cell-based studies in wildlife proteomics, and highlights that proteins detected in vitro could act as biomarkers of chemical exposure and effect in vivo.