Department of Genetics, University Medical Center Utrecht, 3584 EA Utrecht, the Netherlands; Center for Molecular Medicine, University Medical Center Utrecht, 3584 EA Utrecht, the Netherlands.
Department of Genetics, University Medical Center Utrecht, 3584 EA Utrecht, the Netherlands.
Biochim Biophys Acta Mol Basis Dis. 2020 Mar 1;1866(3):165607. doi: 10.1016/j.bbadis.2019.165607. Epub 2019 Nov 21.
Pyridox(am)ine 5'-phosphate oxidase (PNPO) catalyzes oxidation of pyridoxine 5'-phosphate (PNP) and pyridoxamine 5'-phosphate (PMP) to pyridoxal 5'-phosphate (PLP), the active form of vitamin B. PNPO deficiency results in neonatal/infantile seizures and neurodevelopmental delay. To gain insight into this disorder we generated Pnpo deficient (pnpo) zebrafish (CRISPR/Cas9 gene editing). Locomotion analysis showed that pnpo zebrafish develop seizures resulting in only 38% of pnpo zebrafish surviving beyond 20 days post fertilization (dpf). The age of seizure onset varied and survival after the onset was brief. Biochemical profiling at 20 dpf revealed a reduction of PLP and pyridoxal (PL) and accumulation of PMP and pyridoxamine (PM). Amino acids involved in neurotransmission including glutamate, γ-aminobutyric acid (GABA) and glycine were decreased. Concentrations of several, mostly essential, amino acids were increased in pnpo zebrafish suggesting impaired activity of PLP-dependent transaminases involved in their degradation. PLP treatment increased survival at 20 dpf and led to complete normalization of PLP, PL, glutamate, GABA and glycine. However, amino acid profiles only partially normalized and accumulation of PMP and PM persisted. Taken together, our data indicate that not only decreased PLP but also accumulation of PMP may play a role in the clinical phenotype of PNPO deficiency.
吡哆醇 5'-磷酸氧化酶 (PNPO) 催化吡哆醇 5'-磷酸 (PNP) 和吡哆胺 5'-磷酸 (PMP) 氧化为吡哆醛 5'-磷酸 (PLP)，这是维生素 B 的活性形式。PNPO 缺乏导致新生儿/婴儿癫痫发作和神经发育迟缓。为了深入了解这种疾病，我们生成了缺乏 PNPO 的斑马鱼 (CRISPR/Cas9 基因编辑)。运动分析表明，pnpo 斑马鱼会出现癫痫发作，只有 38%的 pnpo 斑马鱼能在受精后 20 天 (dpf) 后存活。癫痫发作的发病年龄不同，发病后的存活时间很短。20 dpf 的生化特征分析显示 PLP 和吡哆醛 (PL) 减少，PMP 和吡哆胺 (PM) 积累。包括谷氨酸、γ-氨基丁酸 (GABA) 和甘氨酸在内的参与神经递质传递的氨基酸减少。几种，主要是必需氨基酸的浓度在 pnpo 斑马鱼中增加，表明参与其降解的 PLP 依赖性转氨酶的活性受损。PLP 治疗增加了 20 dpf 的存活率，并使 PLP、PL、谷氨酸、GABA 和甘氨酸完全正常化。然而，氨基酸谱仅部分正常化，PMP 和 PM 的积累仍然存在。总的来说，我们的数据表明，不仅 PLP 减少，而且 PMP 的积累也可能在 PNPO 缺乏的临床表型中起作用。
