In vitro microarray analysis identifies genes in acute-phase response pathways that are down-regulated in the liver of chicken embryos exposed in ovo to PFUdA

Abstract

Perfluoroundecanoic acid (PFUdA) is one of the most highly detected perfluoroalkyl compounds in wild bird tissues and eggs. Although PFUdA does not affect hatching success, many PFCs are known to impair post-hatch development and survival. Here we use microarrays to survey the transcriptional response of cultured chicken embryonic hepatocytes (CEH) to PFUdA for potential targets of PFUdA action that could lead to developmental deficiencies in exposed birds. At 1 μM and 10 μM PFUdA significantly altered the expression of 346 and 676 transcripts, respectively (fold-change>1.5, p<0.05, false discovery rate-corrected). Using functional, pathway and interactome analysis we identified several potentially important targets of PFUdA exposure, including the suppression of the acute-phase response (APR). We then measured the expression of five APR genes, fibrinogen alpha (fga), fibrinogen gamma (fgg), thrombin (f2), plasminogen (plg), and protein C (proC), in the liver of chicken embryos exposed in ovo to PFUdA. The expression of fga, f2, and proC were down-regulated in embryo livers (100 or 1000 ng/g, p<0.1) as predicted from microarray analysis, whereas fibrinogen gamma (fgg) was up-regulated and plg was not significantly affected. Our results demonstrate the utility of CEH coupled with transcriptome analysis as an in vitro screening tool for identifying novel effects of toxicant exposure. Additionally, we identified APR suppression as a potentially important and environmentally relevant target of PFUdA. These findings suggest in ovo exposure of birds to PFUdA may lead to post-hatch developmental deficiencies, such as impaired inflammatory response.

Keywords: APR; CEH; Chicken; DE; DMSO; FDR; GSH; Gene-expression; HNF4A; Hepatocyte; IPA; Ingenuity Pathway Analysis; Mode of action; PFC; PFCA; PFDS; PFNA; PFOA; PFOS; PFUdA; PPARα; PPARγ; Perfluorooctane sulfonate; Perfluoroundecanoic acid; TP53; a2m; acute-phase response; alpha-2-macroglobulin; carboxypeptidase B2; cdo1; chicken embryonic hepatocytes; cpb2; cysteine dioxygenase type I; differentially expressed; dimethyl sulfoxide; f2; false discovery rate; fga; fgg; fibrinogen alpha; fibrinogen gamma; glutathione; glutathione-S-transferase alpha 3; glutathione-S-transferase alpha 4; glutathione-S-transferase omega 1; gsta3; gsta4; gsto1; hepatocyte nuclear factor 4 alpha; interferon stimulated gene 12 protein-like 2; isg12-2; lbfabp; liver basic fatty acid binding protein; mgst1; microsomal glutathione-S-transferase 1; perfluoroalkyl compound; perfluorocarboxylic acid; perfluorodecane sulfonate; perfluorononanoic acid; perfluorooctane sulfonate; perfluorooctanoic acid; perfluoroundecanoic acid; perosixome proliferator-activated receptor alpha; peroxisome proliferator-activated receptor gamma; plasminogen; plg; proC; protein C; thrombin (coagulation factor II); tumor protein 53.