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 B6. 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.

中文翻译：

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斑马鱼中的吡rid醇（胺）5'-磷酸氧化酶（PNPO）缺乏会导致致命的癫痫发作和代谢异常。

吡rid胺（5）-磷酸氧化酶（PNPO）催化吡pyr醇5'-磷酸（PNP）和吡ido胺5'-磷酸（PMP）氧化为吡ido醛5'-磷酸（PLP），这是维生素B6的活性形式。PNPO缺乏会导致新生儿/婴儿癫痫发作和神经发育延迟。为了深入了解这种疾病，我们生成了Pnpo缺陷（pnpo-/-）斑马鱼（CRISPR / Cas9基因编辑）。运动分析表明，pnpo-/-斑马鱼会发作，导致仅38％的pnpo-/-斑马鱼在受精后（dpf）存活超过20天。癫痫发作的年龄各不相同，发作后的生存期很短。20 dpf的生化分析显示PLP和吡ido醛（PL）减少，PMP和吡ido胺（PM）积累。与神经传递有关的氨基酸，包括谷氨酸，γ-氨基丁酸（GABA）和甘氨酸减少。pnpo-/-斑马鱼中几种（主要是必需的）氨基酸的浓度增加，表明参与其降解的PLP依赖性转氨酶活性受损。PLP治疗可提高20 dpf的生存率，并导致PLP，PL，谷氨酸，GABA和甘氨酸完全正常化。但是，氨基酸谱仅部分归一化，PMP和PM的积累持续存在。两者合计，我们的数据表明，不仅PLP降低，而且PMP的积累也可能在PNPO缺乏症的临床表型中起作用。PLP治疗可提高20 dpf的生存率，并导致PLP，PL，谷氨酸，GABA和甘氨酸完全正常化。但是，氨基酸谱仅部分归一化，PMP和PM的积累持续存在。两者合计，我们的数据表明，不仅PLP降低，而且PMP的积累也可能在PNPO缺乏症的临床表型中起作用。PLP治疗可提高20 dpf的生存率，并导致PLP，PL，谷氨酸，GABA和甘氨酸完全正常化。但是，氨基酸谱仅部分归一化，PMP和PM的积累持续存在。两者合计，我们的数据表明，不仅PLP降低，而且PMP的积累也可能在PNPO缺乏症的临床表型中起作用。