Lavrenova Anna, Klychnikov Oleg, Ioutsi Vitaliy, Rodin Igor, Luneva Oksana, Nefedova Lidia
Department of Genetics, Faculty of Biology, M. V. Lomonosov Moscow State University, 119234 Moscow, Russia.
Department of Biochemistry, Faculty of Biology, M. V. Lomonosov Moscow State University, 119234 Moscow, Russia.
Int J Mol Sci. 2025 May 17;26(10):4808. doi: 10.3390/ijms26104808.
In vertebrates, vitamin K is a cofactor for the gamma-glutamyl carboxylase (GGCX) involved in the carboxylation of glutamic acid residues. During the vitamin K cycle, vitamin K is oxidised by GGCX, and then reduced by vitamin K epoxide reductase (VKOR), which is inhibited by the synthetic coumarin warfarin. GGCX and VKOR are present in , but the existence of a vitamin K cycle remains unproven. Semi-lethal concentrations (LC) of K, menadione sodium bisulfite (MSB), and warfarin to neutralise the negative effect of MSB were selected for the Drosophila cultivation medium. LC-MS analysis was used for vitamin K measurement in flies' extracts. The EPR method and RT-PCR were used for ROS level measurement and gene transcription assessment, respectively. The LC of MSB in the medium resulted in a more than 20-fold increase in endogenous K in flies, demonstrating the mechanism of K-to-K conversion. Administration of 1 mM warfarin in the medium with MSB completely neutralised its negative effect on viability. Developed flies had decreased K level, confirming the existence of a vitamin K cycle, and both reduced ROS level and gene transcription. The biochemical pathways affected by elevated K concentrations involves both elements of the vitamin K cycle and the adaptive mitochondrial antioxidant system.
在脊椎动物中，维生素K是γ-谷氨酰羧化酶（GGCX）的一种辅助因子，该酶参与谷氨酸残基的羧化过程。在维生素K循环中，维生素K被GGCX氧化，然后被维生素K环氧化物还原酶（VKOR）还原，而合成香豆素华法林可抑制VKOR。GGCX和VKOR存在于……中，但维生素K循环的存在尚未得到证实。选择K、亚硫酸氢钠甲萘醌（MSB）的半致死浓度（LC）以及用于中和MSB负面影响的华法林，用于果蝇培养基。采用液相色谱-质谱联用（LC-MS）分析测定果蝇提取物中的维生素K含量。分别采用电子顺磁共振（EPR）方法和逆转录-聚合酶链反应（RT-PCR）测定活性氧（ROS）水平和评估基因转录情况。培养基中MSB的LC导致果蝇体内内源性K增加20多倍，证明了K到K的转化机制。在含有MSB的培养基中加入1 mM华法林可完全中和其对活力的负面影响。发育成熟的果蝇体内K水平降低，证实了维生素K循环的存在，同时ROS水平和基因转录均降低。受K浓度升高影响的生化途径涉及维生素K循环的要素和适应性线粒体抗氧化系统。
