Characterization of Cyclooxygenase-2 and its induction pathways in response to high lipid diet-induced inflammation in Larmichthys crocea.

Tianjiao Wang,Kangsen Mai,Jing Yan,Qinghui Ai,Wei Xu

doi:10.1038/srep19921

Tianjiao Wang, Kangsen Mai + Show 3 more

Open Access

https://doi.org/10.1038/srep19921

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Journal: Scientific reports	Publication Date: Feb 1, 2016
Citations: 41	License type: CC BY 4.0

Affiliation: Ocean University of China

Abstract

The present study was conducted to investigate the effects of a high-lipid diet (HLD) on cyclooxygenase (Cox)-2 expression and the signalling pathways related to low-grade inflammation in the large yellow croaker (Larmichthys crocea). An isolated 2508 bp cDNA clone of cox-2 contained an open reading frame spanning 1827 bp encoding a protein with 608 amino acid residues. The over-expression of cox-2 was consistent with the activation of c-Jun N-terminal kinases (JNKs) and p38 mitogen-activated protein kinase (MAPK) in HLD-fed fish. The activation of the activator protein-1 (AP-1) and the nuclear transcription factor kappa-B (NF-κB) signalling pathways in HLD-fed fish and the significant increase of cox-2 promoter-luciferase activity in vitro indicated that AP-1 and NF-κB could combine cox-2 promoter to promote its transcription, respectively. Together, HLD-induced inflammation up-regulates cox-2 expression via JNKs and p38 MAPK-dependent NF-κB and AP-1 pathways. The present study provides important insight into the signal transduction pathways involved in HLD-induced inflammation, which is detrimental to the health and production of fish as well as to the health of fish consumers.

Highlights

A high lipid diet (HLD), containing higher lipid concentration than appropriate, has been increasingly used for the development of cost-effective aquaculture, mainly due to its protein sparing effect[1], meaning that high-lipid diet (HLD) could be more beneficial for improving protein utilization in tissue synthesis than for acting as an energy source and could maximize nitrogen retention in fish
The full-length cDNA of cox-2 from large yellow croaker was 2508 bp (GenBank Accession No KP259877), including a 5′ untranslated terminal region (UTR) of 106 bp, a 3′ UTR of 575 bp, and an open reading frame (ORF) of 1827 bp encoding a polypeptide of 608 amino acid residues with a predicted molecular weight of 69.03 KDa and a theoretical isoelectric point of 6.74 (Fig. 1)
The HLD increased the phosphorylation of Jun N-terminal kinases (JNKs) and p38 mitogen-activated protein kinase (MAPK) in HLD fish compared to the control group, whereas no significant effect on the phosphorylation status of ERK1/2 was observed among the different lipid levels (Fig. 7)

Summary

Introduction

A high lipid diet (HLD), containing higher lipid concentration than appropriate (the control), has been increasingly used for the development of cost-effective aquaculture, mainly due to its protein sparing effect[1], meaning that HLD could be more beneficial for improving protein utilization in tissue synthesis than for acting as an energy source and could maximize nitrogen retention in fish. Previous studies have indicated that lipid deposition and inflammatory signals of the large yellow croaker are strikingly similar to those of other fish species and mammals[23]. In this study, cox-2 from large yellow croaker was cloned and characterized, and the effect of a HLD on cox-2 expression and the signalling transduction pathway involved were investigated.

Results

Conclusion