Aryl hydrocarbon receptor protein and Cyp1A1 gene induction by LPS and phenanthrene in Atlantic cod (Gadus morhua) head kidney cells

• Published in: Fish & shellfish immunology 2014-10, Vol.40 (2), p.384-391
• Main Authors: Holen, Elisabeth, Olsvik, Pål Asgeir
• Format: Article
• Language: English
• Subjects: AhR; Animal Feed - analysis; Animals; CYP1A1; Cytochrome P-450 CYP1A1 - genetics; Cytochrome P-450 CYP1A1 - metabolism; Fish Proteins - genetics; Fish Proteins - metabolism; Gadus morhua; Gadus morhua - genetics; Gadus morhua - immunology; Gadus morhua - metabolism; Gene Expression Regulation - drug effects; Head Kidney - metabolism; Lipopolysaccharides - physiology; LPS; Phenanthrenes - pharmacology; Pheneanthrene; Poly I-C - pharmacology; poly I:C; Real-Time Polymerase Chain Reaction - veterinary; Receptors, Aryl Hydrocarbon - genetics; Receptors, Aryl Hydrocarbon - metabolism
• ISSN: 1050-4648; 1095-9947
• DOI: 10.1016/j.fsi.2014.07.022

The objective of this study was to evaluate interactions between environmental toxicants and cod immune cells during inflammation. Phenanthrene is abundant in plant oils (rapeseed, palm, and soya oil) as compared to fish oils, and consequently constitute an undesirable element in plant replacement diets in aquaculture. Phenanthrene was added to head kidney cell cultures, alone or together with LPS (lipopolysaccharide) or poly I: C (polyinosinic acid: polycytidylic acid), and the responses were evaluated in terms of protein and gene expression. The results showed that LPS, poly I: C or phenanthrene, added to the cultures separately, induced aryl hydrocarbon receptor (AhR) protein expression. Phenanthrene treatment in combination with LPS induced AhR protein expression and Cyp1A1 gene transcription, which not was observed combining poly I: C and phenanthrene. Phenanthrene exposure up regulated the transcription of common stress and detoxification enzymes like catalase, caspase 3 and glutathione S-transferase alfa 3 subunit B (GSTAB3), while LPS exposure alone or combined with phenanthrene down regulated GSTAB3 and catalase in cod leukocytes. It seems clear that immune regulation and phenanthrene induced signaling pathways interact; transcriptional down regulation of detoxification and antioxidant enzymes by LPS could indicate that combating bacterial infections is the number one priority in these cells, and that AhR and Cyp1A1 is somehow involved in this signaling cascade. LPS seems to affect the mitogen activated protein kinases (MAPKs) pathways (P-p38 and ERK1/2) thus modulating the AhR protein and Cyp1A1 gene transcription, while phenanthrene possibly activates AhR by ligand binding. •AhR protein was up-regulated by LPS, poly I: C and phenanthrene.•CYP1A1 gene transcription was up-regulated by LPS and phenanthrene.•LPS down-regulated transcription of common detoxification, apoptosis and antioxidant enzymes.•Phenanthrene up-regulated transcription of common detoxification and antioxidant enzymes.•Phenanthrene affected the fish specific PAMPs, TLR22H and antiviral ISG15.