Molecular characterization and tissue distribution of SREBP-1 and PPARα in Onychostoma macrolepis and their mRNA expressions in response to thermal exposure
Molecular characterization and tissue distribution of SREBP-1 and PPARα in Onychostoma macrolepis and their mRNA expressions in response to thermal exposure
复制标题
大鳞甲鱼中 SREBP-1 和 PPAR α 的分子特征和组织分布及其热暴露响应的 mRNA 表达
DOI：
10.1016/j.cbpa.2018.12.009
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发表时间：
2019-04-01
影响因子：
2.3
通讯作者：
Ji, Hong
中科院分区：
文献类型：
--
作者：
Deng, Wei;Yu, Hai-bo;Ji, Hong
脂肪酸代谢是水生脊椎动物在承受环境压力时维持能量稳态的关键。甾醇调节元件结合蛋白1 （SREBP-1）和过氧化物酶体增殖物激活受体α (PPAR α)都是脂肪酸代谢的关键调节因子。本研究首次从大lepis Onychostoma中鉴定出SREBP-1和PPAR α的编码序列（CDS），分别编码1136个和470个氨基酸。大鼠O. macrolepis SREBP-1和PPAR α蛋白的功能域与其他动物保持着较高的相似性，分别为74.69%和77.29%。编码SREBP-1的mRNA主要在肌肉中表达，PPAR α在肝脏和肠道中高度表达。在热暴露条件下，大腹蛇肝脏和肌肉中的非酯化脂肪酸（NEFA）含量在1 h后逐渐下降，这可能是由于机体通过脂肪酸β -氧化来满足更多的能量消耗。肝组织中SREBP-1 mRNA表达量在0 ~ 6 h呈下降趋势，PPAR α mRNA表达量在6 h呈上升趋势。我们发现肌肉中SREBP-1和PPAR α的mRNA表达量在48 h时均显著降低（P < 0.05），这与靶基因FAS和CPT1A mRNA表达量分别显著降低一致。实验结束时，鱼对热暴露的适应可能是一种生理调节。这些结果表明，O. macrolepis SREBP-1和PPAR α介导的脂肪酸代谢是热适应的基本要求。
Fatty acid metabolism is crucial for maintaining energy homeostasis in aquatic vertebrates experiencing environmental stress. Both sterol regulatory element-binding protein 1 (SREBP-1) and peroxisome proliferator-activated receptor alpha (PPAR alpha) are the key regulators of fatty acid metabolism. In this study, the coding sequences (CDS) of SREBP-1 and PPAR alpha were firstly identified and characterized from Onychostoma macrolepis, encoding peptides of 1136 and 470 amino acids, respectively. The functional domains in O. macrolepis SREBP-1 and PPAR alpha proteins retained the high similarity with those of other animals, at 74.69% and 77.29%, respectively. The mRNA encoding SREBP-1 was primarily expressed in the muscle and PPAR alpha was highly expressed in the liver and intestine. Under thermal exposure, the content of non-esterified fatty acid (NEFA) decreased gradually after 1 h in the liver and muscle of O. macrolepis, which might be due to that the organism meet more energy expenditure via fatty acid beta-oxidation. Furthermore, the mRNA expression level of SREBP-1 decreased, while the mRNA expression level of PPAR alpha increased from 0 h to 6 h in the liver. And we found that the mRNA expression levels of both SREBP-1 and PPAR alpha decreased significantly at 48 h (P < .05) in the muscle, which was in accordance with the significant decrease of target gene FAS and CPT1A mRNA expression levels, respectively. It might be the physiological adjustment that the fish adapted to thermal exposure at the end of experiment. These results illustrate that O. macrolepis SREBP-1 and PPAR alpha-mediated fatty acid metabolism is a fundamental requirement for thermal adaptation.