Lu Ke, Wu Jiaqi, Zhang Yanpeng, Zhuang Wuyuan, Liang Xu-Fang
College of Fisheries, Chinese Perch Research Center, Huazhong Agricultural University, No.1, Shizishan Street, Wuhan, 430070, Hubei Province, China.
Engineering Research Center of Green Development for Conventional Aquatic Biological Industry in the Yangtze River Economic Belt, Ministry of Education, Wuhan, 430070, China.
Funct Integr Genomics. 2023 Feb 25;23(1):67. doi: 10.1007/s10142-023-00993-6.
Carbohydrates are the most economical source of energy in fish feeds, but most fish have limited ability to utilize carbohydrates. It has been reported that phosphoenolpyruvate carboxykinase 1 (pck1) is involved in carbohydrate metabolism, lipid metabolism, and other metabolic processes. However, direct evidence is lacking to fully understand the relationship between pck1 and glucose and lipid metabolism. Here, we generated a pck1 knockout zebrafish by CRISPR/cas9 system, and a high-carbohydrate diet was provided to 60 days post-fertilization (dpf) for 8 weeks. We found that pck1-deficient zebrafish displayed decreased plasma glucose, elevated mRNA levels of glycolysis-related genes (gck, pfk, pk), and reduced the transcriptional levels of gluconeogenic genes (pck1, fbp1a) in liver. We also found decreased triglyceride, total cholesterol, and lipid accumulation and in pck1 zebrafish, along with downregulation of genes for lipolysis (acaca) and lipogenesis (cpt1). In addition, the observation of HE staining revealed that the total muscle area of pck1 was substantially less than that of WT zebrafish and real-time PCR suggested that GH/IGF-1 signaling (ulk2, stat1b) may be suppressed in pck1-deficient fish. Taken together, these findings suggested that pck1 may play an important role in the high-carbohydrate diet utilization of fish and significantly affected lipid metabolism and protein synthesis in zebrafish. pck1 knockout mutant line could facilitate a further mechanism study of pck1-associated metabolic regulation and provide new information for improving carbohydrate utilization traits.
碳水化合物是鱼类饲料中最经济的能量来源，但大多数鱼类利用碳水化合物的能力有限。据报道，磷酸烯醇丙酮酸羧激酶1（pck1）参与碳水化合物代谢、脂质代谢和其他代谢过程。然而，缺乏直接证据来充分了解pck1与葡萄糖和脂质代谢之间的关系。在此，我们通过CRISPR/cas9系统构建了pck1基因敲除斑马鱼，并在受精后60天（dpf）给予高碳水化合物饲料喂养8周。我们发现，pck1基因缺陷的斑马鱼血浆葡萄糖水平降低，糖酵解相关基因（gck、pfk、pk）的mRNA水平升高，肝脏中糖异生基因（pck1、fbp1a）的转录水平降低。我们还发现pck1基因敲除斑马鱼的甘油三酯、总胆固醇和脂质积累减少，同时脂肪分解（acaca）和脂肪生成（cpt1）相关基因的表达下调。此外，HE染色观察显示，pck1基因敲除斑马鱼的总肌肉面积明显小于野生型斑马鱼，实时PCR结果表明，pck1基因缺陷的斑马鱼中生长激素/胰岛素样生长因子-1信号通路（ulk2、stat1b）可能受到抑制。综上所述，这些发现表明pck1可能在鱼类高碳水化合物饲料利用中发挥重要作用，并显著影响斑马鱼的脂质代谢和蛋白质合成。pck1基因敲除突变系有助于进一步研究pck1相关的代谢调控机制，并为改善碳水化合物利用性状提供新的信息。
