Huang Lu, Yao Weilei, Wang Tongxin, Li Juan, He Qiongyu, Huang Feiruo
Department of Animal Nutrition and Feed Science, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
Metabolites. 2020 Apr 9;10(4):146. doi: 10.3390/metabo10040146.
Weaning significantly alters hepatic aromatic amino acid (AAA) metabolism and physiological functions. However, less is known about the regulating mechanism of hepatic AAA metabolism after weaning. A total of 200 21-day-old piglets (Duroc × Landrace) were assigned randomly to the control group and the weaning group. In this study, weaning significantly decreased the concentration of phenylalanine, tryptophan, and tyrosine in piglet livers ( < 0.05). Additionally, through the detection of liver AAA metabolites and metabolic enzyme activity, it was observed that hepatic tryptophan catabolism was enhanced, while that of phenylalanine was weakened ( < 0.05). Intriguingly, acetyl-proteome profiling of liver from weaned piglets showed that weaning exacerbated the acetylation of phenylalanine hydroxylase (PAH) and the deacetylation of tryptophan 2,3-dioxygenase (TDO). Analysis of PAH and TDO acetylation in Chang liver cells showed that acetylation decreased the PAH activity, while deacetylation increased the TDO activity ( < 0.05). Furthermore, metabolites of AAAs and the acetylation statuses of PAH and TDO in primary hepatocytes from weaned piglets were consistent with the results . These findings indicated that weaning altered the PAH and TDO activity by affecting the acetylation state of the enzyme in piglets'' livers. Lysine acetylation may be a potential regulatory mechanism for AAA metabolism in response to weaning.
断奶会显著改变肝脏芳香族氨基酸（AAA）代谢及生理功能。然而，关于断奶后肝脏AAA代谢的调控机制，我们了解得较少。总共200头21日龄仔猪（杜洛克×长白）被随机分配到对照组和断奶组。在本研究中，断奶显著降低了仔猪肝脏中苯丙氨酸、色氨酸和酪氨酸的浓度（P<0.05）。此外，通过检测肝脏AAA代谢产物和代谢酶活性，观察到肝脏色氨酸分解代谢增强，而苯丙氨酸分解代谢减弱（P<0.05）。有趣的是，对断奶仔猪肝脏的乙酰化蛋白质组分析表明，断奶加剧了苯丙氨酸羟化酶（PAH）的乙酰化和色氨酸2,3-双加氧酶（TDO）的去乙酰化。在Chang肝细胞中对PAH和TDO乙酰化的分析表明，乙酰化降低了PAH活性，而去乙酰化增加了TDO活性（P<0.05）。此外，断奶仔猪原代肝细胞中AAA的代谢产物以及PAH和TDO的乙酰化状态与上述结果一致。这些发现表明，断奶通过影响仔猪肝脏中酶的乙酰化状态改变了PAH和TDO的活性。赖氨酸乙酰化可能是断奶后AAA代谢的一种潜在调控机制。
