大菱鲆脂质代谢相关基因PPARs的组织表达及其对高温胁迫的响应

Tissue expression of lipid metabolism related genes PPARs and their responses to heat stress in turbot (Scophthalmus maximus)

摘要:

为研究大菱鲆过氧化物酶体增殖物激活受体家族(PPARs)的组织分布和高温胁迫下PPARs在肾脏中的表达情况。实验采用荧光定量PCR(qPCR)技术检测PPARs基因3种亚型在大菱鲆不同组织中的表达情况以及高温胁迫下大菱鲆肾脏中PPARs的表达情况。qPCR结果显示，大菱鲆PPARs 3种亚型的组织分布存在显著差异。PPARα1和PPARα2在心脏中的表达量显著高于其他组织；PPARβ在大菱鲆的各个组织中普遍表达；PPARγ在大菱鲆的鳃中出现了显著性的高表达。大菱鲆肾脏中PPARs的mRNA水平随着温度升高呈现出不同的响应模式。PPARα随温度升高表达水平先显著降低，后有所升高；PPARβ的表达量在14、20、23和25 ℃时差异不显著，当温度升高至大菱鲆的致死温度28 ℃时，表达量出现了显著性的升高；PPARγ在14 ℃时表达水平很低，但随着温度的升高不断增加。研究表明，大菱鲆中存在PPARα、PPARβ和PPARγ 3种亚型，而且三者可能以组织特异性的方式参与脂质代谢的调节，首次指出PPARs 3种亚型在温度胁迫中的表达变化，对PPARs的研究将推动鱼类脂代谢研究，揭示鱼类PPARs在脂质代谢调控以及响应逆境胁迫中的重要作用。

关键词:大菱鲆;脂质代谢;过氧化物酶体增殖物激活受体(PPARs);基因表达;高温胁迫

Abstract:

Scophthalmus maximus is a commercially valuable flatfish and one of most promising aquaculture species in Europe. Since S. maximus was introduced into China in 1990s, it has been a major maricultured fish in northern coastal areas of China. As a kind of cold-water fish, S. maximus has strict requirements for breeding temperature, which greatly limits the breeding range of this important marine fish. Therefore, it is of great research significance to explore the mechanism of heat-resistance in turbot. In this paper, tissue distribution of PPARs and the expression of PPARs in kidney at different temperature were analyzed by qPCR.The results showed that there are significant differences in the tissue distribution of the three subtypes of S. maximus PPARs. PPARα1 and PPARα2 were markedly expressed in the heart, PPARβ was widely distributed in various tissues of S. maximus, while PPARγ was significantly expressed in the gill of S. maximus. What's more, the transcript abundance of PPARs in S. maximus kidney showed different response patterns to the elevated temperature. At 20 ℃, the expression level of PPARα diminished dramatically and then increased with the elevated temperature. The expression of PPARβ was not significantly different at 14, 20, 23 and 25 ℃, however, its transcript abundance increased significantly when the temperature was increased to the lethal temperature of S. maximus at 28 ℃. The expression level of PPARγ showed a tendency to increase with increasing temperature. In summary, our results revealed that there are three subtypes PPARα, PPARβ and PPARγ in S. maximus, which may be involved in the regulation of lipid metabolism in a tissue-specific manner, and more importantly, the expression of three subtypes of PPARs under thermal stress was pointed out for the first time. Collectively, these studies will shed light on the regulation mechanism of PPARs on lipid metabolism in the kidney of S. maximus during heat stress, which will promote the further study of fish lipid metabolism.

Key words:Scophthalmus maximus;lipid metabolism;peroxisome proliferator activated receptors (PPARs);gene expression;heat stress