北京大学魏文胜等共同合作，近期取得重要工作进展。他们利用优化的线粒体碱基编辑器（mitoBE）精准构建线粒体疾病模型。相关研究成果2025年1月22日在线发表于《自然》杂志上。

据介绍，动物模型的开发对于线粒体疾病的研究和治疗至关重要。

研究人员对腺嘌呤和胞嘧啶脱氨酶进行了优化，以减少对转录组和线粒体基因组的脱靶效应，从而提高了新开发的线粒体碱基编辑器（mitoBE）的准确性和效率。利用这些升级后的mitoBE（版本2，即v2），研究人员针对70种与人类致病变体类似的小鼠线粒体DNA突变展开研究，为线粒体疾病小鼠模型的建立奠定了基础。

环状RNA编码的mitoBE v2在小鼠体内实现了高达82%的编辑效率，且在核基因组中未检测到脱靶效应。经编辑的线粒体DNA在各种组织中持续存在，并能通过母系遗传，使得F1代小鼠的突变负载率高达100%，部分小鼠仅在目标位点发生编辑。

通过优化转录激活因子样效应物（TALE）结合位点，研究人员构建了针对mt-Nd5 A12784G突变的单碱基编辑小鼠模型。表型评估促使研究人员成功建立了mt-Atp6 T8591C和mt-Nd5 A12784G突变的小鼠模型，这两种模型分别表现出与Leigh综合征患者心率降低，以及Leber遗传性视神经病变患者视力丧失相对应的表型。

此外，研究发现mt-Atp6 T8591C突变比mt-Nd5 A12784G突变更具危害性，它会影响胚胎发育，且在连续几代中迅速减少。这些升级后的mitoBE为构建线粒体疾病模型提供了一种高效且精确的策略，为该领域的进一步研究奠定了基础。

附：英文原文

Title: Precise modelling of mitochondrial diseases using optimized mitoBEs

Author: Zhang, Xiaoxue, Zhang, Xue, Ren, Jiwu, Li, Jiayi, Wei, Xiaoxu, Yu, Ying, Yi, Zongyi, Wei, Wensheng

Issue&Volume: 2025-01-22

Abstract: The development of animal models is crucial for studying and treating mitochondrial diseases. Here we optimized adenine and cytosine deaminases to reduce off-target effects on the transcriptome and the mitochondrial genome, improving the accuracy and efficiency of our newly developed mitochondrial base editors (mitoBEs)1. Using these upgraded mitoBEs (version 2 (v2)), we targeted 70 mouse mitochondrial DNA mutations analogous to human pathogenic variants2, establishing a foundation for mitochondrial disease mouse models. CircularRNA-encoded mitoBEs v2 achieved up to 82% editing efficiency in mice without detectable off-target effects in the nuclear genome. The edited mitochondrial DNA persisted across various tissues and was maternally inherited, resulting in F1 generation mice with mutation loads as high as 100% and some mice exhibiting editing only at the target site. By optimizing the transcription activator-like effector (TALE) binding site, we developed a single-base-editing mouse model for the mt-Nd5 A12784G mutation. Phenotypic evaluations led to the creation of mouse models for the mt-Atp6 T8591C and mt-Nd5 A12784G mutations, exhibiting phenotypes corresponding to the reduced heart rate seen in Leigh syndrome and the vision loss characteristic of Leber’s hereditary optic neuropathy, respectively. Moreover, the mt-Atp6 T8591C mutation proved to be more deleterious than mt-Nd5 A12784G, affecting embryonic development and rapidly diminishing through successive generations. These upgraded mitoBEs offer a highly efficient and precise strategy for constructing mitochondrial disease models, laying a foundation for further research in this field.

DOI: 10.1038/s41586-024-08469-8

Source: https://www.nature.com/articles/s41586-024-08469-8