Shi Zhijie, Pang Yuning, Xu Xiang, Lai Wencong, Cao Xiufei, Mai Kangsen, Ai Qinghui
Key Laboratory of Aquaculture Nutrition and Feed, Ministry of Agriculture and Rural Affairs, and Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, 5 Yushan Road, Qingdao, Shandong 266003, People's Republic of China.
Key Laboratory of Aquaculture Nutrition and Feed, Ministry of Agriculture and Rural Affairs, and Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, 5 Yushan Road, Qingdao, Shandong 266003, People's Republic of China; Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, 1 Wenhai Road, Qingdao, Shandong 266237, People's Republic of China.
Comp Biochem Physiol B Biochem Mol Biol. 2023 Jun-Jul;266:110850. doi: 10.1016/j.cbpb.2023.110850. Epub 2023 Mar 28.
3-hydroxyacyl-CoA dehydratases 1 (Hacd1) is a critical enzyme in long-chain polyunsaturated fatty acids (LC-PUFA) biosynthesis. The difference in expression of hacd1 might account for the stronger capacity of LC-PUFA biosynthesis in freshwater fish than in marine fish, but little is known about fish hacd1. Therefore, this study compared the responses of large yellow croaker and rainbow trout hacd1 to different oil sources or fatty acids, and also examined transcriptional regulation of this gene. In this study, hacd1 was highly expressed in the liver of large yellow croaker and rainbow trout, which is the main organ for LC-PUFA biosynthesis. Therefore, we cloned the hacd1 coding sequence, with a phylogenetic analysis showing that this gene is evolutionarily conserved. Its localization to the endoplasmic reticulum (ER), likely also indicates a conserved structure and function. The expression of hacd1 in the liver was significantly decreased after the substitution of soybean oil (SO) for fish oil but was not significantly affected after palm oil (PO) substitution. Linoleic acid (LA) incubation significantly promoted hacd1 expression in primary hepatocytes of large yellow croaker and eicosapentaenoic acid (EPA) incubation significantly promoted hacd1 expression in primary hepatocytes of rainbow trout. Transcription factors STAT4, C/EBPα, C/EBPβ, HNF1, HSF3 and FOXP3 were identified in both large yellow croaker and rainbow trout. HNF1 had a stronger activation effect in rainbow trout than in large yellow croaker. FOXP3 inhibited hacd1 promoter activity in large yellow croaker but had no effect in rainbow trout. Therefore, the differences between HNF1 and FOXP3 affected the expression of hacd1 in the liver thus being responsible for the high capacity of LC-PUFA biosynthesis in rainbow trout.
3-羟基酰基辅酶A脱水酶1（Hacd1）是长链多不饱和脂肪酸（LC-PUFA）生物合成中的关键酶。Hacd1表达的差异可能解释了淡水鱼比海水鱼具有更强的LC-PUFA生物合成能力，但对于鱼类Hacd1了解甚少。因此，本研究比较了大黄鱼和虹鳟鱼Hacd1对不同油源或脂肪酸的反应，并研究了该基因的转录调控。在本研究中，Hacd1在大黄鱼和虹鳟鱼的肝脏中高表达，肝脏是LC-PUFA生物合成的主要器官。因此，我们克隆了Hacd1编码序列，系统发育分析表明该基因在进化上是保守的。其定位于内质网（ER），这可能也表明其结构和功能是保守的。用大豆油（SO）替代鱼油后，肝脏中Hacd1的表达显著降低，但用棕榈油（PO）替代后没有显著影响。亚油酸（LA）孵育显著促进大黄鱼原代肝细胞中Hacd1的表达，二十碳五烯酸（EPA）孵育显著促进虹鳟鱼原代肝细胞中Hacd1的表达。在大黄鱼和虹鳟鱼中均鉴定出转录因子STAT4、C/EBPα、C/EBPβ、HNF1、HSF3和FOXP3。HNF1在虹鳟鱼中的激活作用比在大黄鱼中更强。FOXP3抑制大黄鱼中Hacd1启动子活性，但对虹鳟鱼没有影响。因此，HNF1和FOXP3之间的差异影响了肝脏中Hacd1的表达，从而导致虹鳟鱼具有较高的LC-PUFA生物合成能力。
