Choline and methionine differentially alter methyl carbon metabolism in bovine neonatal hepatocytes.
Choline and methionine differentially alter methyl carbon metabolism in bovine neonatal hepatocytes.
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DOI：
10.1371/journal.pone.0171080
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发表时间：
2017
期刊：
影响因子：
3.7
通讯作者：
White HM
中科院分区：
文献类型：
--
作者：
Chandler TL;White HM
肝脏甲基代谢途径的交叉突出了甲基供体的潜在竞争或补偿。本实验的目的是研究脂肪酸(FA)对原代培养的新生大鼠肝细胞甲基转移和脂代谢相关基因表达的影响。4头新生荷斯坦小牛原代肝细胞单层培养2 4h后，分别加入CC(61、12 8、2 0 2 8和4 5 2 8mmoL/L)和DLm(16、30、10 0、30 0mmoL/L)，按析因实验设计加入或不加1μ/L FA鸡尾酒。处理24 h后，收集上清液进行活性氧(ROS)和极低密度脂蛋白(VLDL)的定量，并收集细胞裂解液进行基因表达的定量。未检测到CC、DLm或FA之间的相互作用。CC和DLm均可降低蛋氨酸腺苷转移酶1A(MAT1A)的表达。增加CC不改变甜菜碱-同型半胱氨酸S-甲基转移酶，但增加5-甲基四氢叶酸-同型半胱氨酸甲基转移酶和亚甲基四氢叶酸还原酶的表达。增加DLm可降低BHMT和MTR的表达，但不影响MTHFR。随着CC和DLm的增加，磷脂酰乙醇胺N-甲基转移酶(PEMT)和微粒体甘油三酯转移蛋白(MTTP)的表达均降低，而肉碱棕榈酰转移酶1A(CPT1A)的表达不受任何一种因素的影响。FA可降低MAT1A、MTR、MTHFR的表达，并有降低PEMT的趋势，但对BHMT和MTTP无明显影响。FA处理可增加CPT1a的表达。增加CC可增加VLDL的分泌，减少ROS的积累。在新生牛肝细胞中，胆碱和蛋氨酸对甲基碳途径有不同的调节作用，提示胆碱可能在捐赠甲基以支持蛋氨酸再生方面发挥关键作用。刺激极低密度脂蛋白的输出和减少ROS的积累表明，增加CC具有保护肝脏的作用。
Intersections in hepatic methyl group metabolism pathways highlights potential competition or compensation of methyl donors. The objective of this experiment was to examine the expression of genes related to methyl group transfer and lipid metabolism in response to increasing concentrations of choline chloride (CC) and DL-methionine (DLM) in primary neonatal hepatocytes that were or were not exposed to fatty acids (FA). Primary hepatocytes isolated from 4 neonatal Holstein calves were maintained as monolayer cultures for 24 h before treatment with CC (61, 128, 2028, and 4528 μmol/L) and DLM (16, 30, 100, 300 μmol/L), with or without a 1 mmol/L FA cocktail in a factorial arrangement. After 24 h of treatment, media was collected for quantification of reactive oxygen species (ROS) and very low-density lipoprotein (VLDL), and cell lysates were collected for quantification of gene expression. No interactions were detected between CC, DLM, or FA. Both CC and DLM decreased the expression of methionine adenosyltransferase 1A (MAT1A). Increasing CC did not alter betaine-homocysteine S-methyltranferase (BHMT) but did increase 5-methyltetrahydrofolate-homocysteine methyltransferase (MTR) and methylenetetrahydrofolate reductase (MTHFR) expression. Increasing DLM decreased expression of BHMT and MTR, but did not affect MTHFR. Expression of both phosphatidylethanolamine N-methyltransferase (PEMT) and microsomal triglyceride transfer protein (MTTP) were decreased by increasing CC and DLM, while carnitine palmitoyltransferase 1A (CPT1A) was unaffected by either. Treatment with FA decreased the expression of MAT1A, MTR, MTHFR and tended to decrease PEMT but did not affect BHMT and MTTP. Treatment with FA increased CPT1A expression. Increasing CC increased secretion of VLDL and decreased the accumulation of ROS in media. Within neonatal bovine hepatocytes, choline and methionine differentially regulate methyl carbon pathways and suggest that choline may play a critical role in donating methyl groups to support methionine regeneration. Stimulating VLDL export and decreasing ROS accumulation suggests that increasing CC is hepato-protective.