Perfluorooctane
sulfonamide (PFOSA), a precursor of perfluorooctanesulfonate
(PFOS), is widely used during industrial processes, though little
is known about its toxicity, particularly to early life stage organisms
that are generally sensitive to xenobiotic exposure. Here, following
exposure to concentrations of 0.01, 0.1, 1, 10, and 100 μg/L
PFOSA, transcriptional, morphological, physiological, and biochemical
assays were used to evaluate the potential effects on aquatic organisms.
The top Tox functions in exposed zebrafish were related to cardiac
diseases predicted by Gene Ontology (GO), Kyoto Encyclopedia of Genes
and Genomes (KEGG) pathway, and Ingenuity Pathway Analysis (IPA) analysis.
Consistent with impacts predicted by transcriptional changes, abnormal
cardiac morphology, disordered heartbeat signals, as well as reduced
heart rate and cardiac output were observed following the exposure
of 0.1, 1, 10, or 100 μg/L PFOSA. Furthermore, these PFOSA-induced
cardiac effects were either prevented or alleviated by supplementation
with an aryl hydrocarbon receptor (AHR) antagonist or ahr2-morpholino knock-down, uncovering a seminal role of AHR in PFOSA-induced
cardiotoxicity. Our results provide the first evidence in fish that
PFOSA can impair proper heart development and function and raises
concern for PFOSA analogues in the natural environment.