不同脂肪酸对大黄鱼碳水化合物反应元件结合蛋白 (ChREBP)的调控作用

Regulation of different fatty acids on carbohydrate response element binding protein (ChREBP) in Larimichthys crocea

  • 摘要:
    目的 探究碳水化合物反应元件结合蛋白 (ChREBP)在鱼类中的功能和对脂肪酸的响应。
    方法 以大黄鱼为研究对象,通过基因克隆技术首先克隆了大黄鱼ChREBP基因的编码序列(CDS);采用实时荧光定量PCR (RT-qPCR)分析ChREBP基因在大黄鱼不同组织中的表达模式;分别用不同脂肪源饲料饲喂大黄鱼10周,分析鱼油组及饲喂棕榈油、橄榄油、亚麻油和豆油的大黄鱼肝脏中ChREBP基因表达量情况。
    结果 大黄鱼ChREBP的CDS序列全长为2 808bp,编码935个氨基酸,并且与哺乳动物ChREBP序列相比具有较高的保守性,因此大黄鱼ChREBP可能具有相对保守的功能。RT-qPCR 实验结果显示,ChREBP基因在大黄鱼肠道和肝脏中的表达量较高;不同脂肪源饲料饲喂大黄鱼10周后,饲喂棕榈油、橄榄油、亚麻油和豆油的大黄鱼肝脏中ChREBP基因表达量较鱼油组(对照组)显著降低;不同脂肪酸孵育大黄鱼肝细胞12 h后,与对照组相比,棕榈酸 (PA,C16:0)处理组ChREBP基因表达量显著降低,而亚油酸 (LA,C18:2n-6)、亚麻酸 (ALA,C18:3n-3)、二十碳五烯酸 (EPA,C20:5n-3)和二十二碳六烯酸 (DHA,C22:6n-3)处理组中ChREBP基因表达量也呈降低的趋势,但无显著差异。
    结论 大黄鱼ChREBP能够在在体和离体水平响应不同脂肪酸的刺激,且在大黄鱼肝脏糖脂代谢调控中可能发挥相对保守的功能。该实验进一步加深了对于鱼类糖脂代谢调控机制的认识,为改善植物油替代引发的大黄鱼糖脂代谢紊乱提供了一定的理论基础。

     

    Abstract: Carbohydrate response element binding protein (ChREBP) is a key transcription factor in the regulation of glucose and lipid metabolism in mammals. However, the function of ChREBP and its response to fatty acids in fish are still unknown. Therefore, in this study, we chose the large yellow croaker (Larimichthys crocea) as the research object, and firstly, this study cloned the sequence of the CDS region of the ChREBP gene in L. crocea. The results found that the full length of the CDS sequence of ChREBP in L. crocea is 2 808 bp, encoding 935 amino acids. Considering that the sequence of ChREBP has a certain degree of homology compared with the sequence of the mammal, ChREBP may have conserved functions in L. crocea. Real-time fluorescence quantitative PCR (RT-qPCR) was used to analyze the expression pattern of ChREBP gene in different tissues of L. crocea, and the results found that the mRNA levels of ChREBP gene were highest in the intestine of L. crocea, while it was also highly expressed in the liver. After 10 weeks of feeding trial, the mRNA levels of ChREBP gene were significantly lower (P < 0.05) in the liver of L. crocea fed palm oil, olive oil, linseed oil, and soya bean oil, compared with fish fed fish oil. After incubation of fish hepatocytes with different fatty acids for 12 h, the mRNA levels of ChREBP gene were significantly (P < 0.05) reduced in the palmitic acid (PA, C16:0) treatment, compared with the control treatment. However, the mRNA levels of ChREBP gene in linoleic acid (LA, C18:2n-6), linolenic acid (ALA, C18:3n-3), eicosapentaenoic acid (EPA, C20:5n-3) and docosahexaenoic acid (DHA, C22:6n-3) treatments also showed a decreasing trend, but there was no significant difference (P > 0.05). The above results indicate that ChREBP of L. crocea could respond to the stimulation of different fatty acids at both in vivo and in vitro levels and might play an important role in the regulation of hepatic glucose and lipid metabolism. The above studies have further deepened the understanding of the mechanism of glucose and lipid metabolism regulation in fish, and provided a theoretical basis for improving the glucose and lipid metabolism disorders induced by the substitution of vegetable oils in L. crocea.

     

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