van de Wal Melissa A E, Doornbos Cenna, Bibbe Janne M, Homberg Judith R, van Karnebeek Clara, Huynen Martijn A, Keijer Jaap, van Schothorst Evert M, 't Hoen Peter A C, Janssen Mirian C H, Adjobo-Hermans Merel J W, Wieckowski Mariusz R, Koopman Werner J H
Department of Pediatrics, Amalia Children's Hospital, Radboud University Medical Center, Nijmegen, the Netherlands; Radboud Center for Mitochondrial Medicine, Radboud University Medical Center, Nijmegen, the Netherlands.
Department of Medical BioSciences, Radboud University Medical Center, Nijmegen, the Netherlands.
Biochim Biophys Acta Proteins Proteom. 2025 Jan 1;1873(1):141055. doi: 10.1016/j.bbapap.2024.141055. Epub 2024 Oct 11.
Paediatric Leigh syndrome (LS) is an early-onset and fatal neurodegenerative disorder lacking treatment options. LS is frequently caused by mutations in the NDUFS4 gene, encoding an accessory subunit of mitochondrial complex I (CI), the first complex of the oxidative phosphorylation (OXPHOS) system. Whole-body Ndufs4 knockout (KO) mice (WB-KO mice) are widely used to study isolated CI deficiency, LS pathology and interventions. These animals develop a brain-specific phenotype via an incompletely understood pathomechanism. Here we performed a quantitative analysis of the sub-brain proteome in six-weeks old WB-KO mice vs. wildtype (WT) mice. Brain regions comprised of a brain slice (BrSl), cerebellum (CB), cerebral cortex (CC), hippocampus (HC), inferior colliculus (IC), and superior colliculus (SC). Proteome analysis demonstrated similarities between CC/HC, and between IC/SC, whereas BrSl and CB differed from these two groups and each other. All brain regions displayed greatly reduced levels of two CI structural subunits (NDUFS4, NDUFA12) and an increased level of the CI assembly factor NDUFAF2. The level of CI-Q module subunits was significantly more reduced in IC/SC than in BrSl/CB/CC/HC, whereas other OXPHOS complex levels were not reduced. Gene ontology and pathway analysis demonstrated specific and common proteome changes between brain regions. Across brain regions, upregulation of cold-shock-associated proteins, mitochondrial fatty acid (FA) oxidation and synthesis (mtFAS) were the most prominent. FA-related pathways were predominantly upregulated in CB and HC. Based upon these results, we argue that stimulation of these pathways is futile and pro-pathological and discuss alternative strategies for therapeutic intervention in LS. SIGNIFICANCE: The Ndufs4 knockout mouse model is currently the most relevant and most widely used animal model to study the brain-linked pathophysiology of human Leigh Syndrome (LS) and intervention strategies. We demonstrate that the Ndufs4 knockout brain engages futile and pro-pathological responses. These responses explain both negative and positive outcomes of intervention studies in Leigh Syndrome mice and patients, thereby guiding novel intervention opportunities.
小儿 Leigh 综合征（LS）是一种起病早且致命的神经退行性疾病，缺乏有效的治疗方法。LS 通常由 NDUFS4 基因突变引起，该基因编码线粒体复合物 I（CI）的一个辅助亚基，CI 是氧化磷酸化（OXPHOS）系统的首个复合物。全身 Ndufs4 基因敲除（KO）小鼠（WB-KO 小鼠）被广泛用于研究孤立性 CI 缺乏、LS 病理学及干预措施。这些动物通过一种尚未完全了解的发病机制形成脑特异性表型。在此，我们对六周龄的 WB-KO 小鼠与野生型（WT）小鼠的脑亚蛋白质组进行了定量分析。脑区包括脑切片（BrSl）、小脑（CB）、大脑皮层（CC）、海马体（HC）、下丘（IC）和上丘（SC）。蛋白质组分析表明 CC/HC 之间以及 IC/SC 之间存在相似性，而 BrSl 和 CB 与这两组不同且彼此也不同。所有脑区中，两种 CI 结构亚基（NDUFS4、NDUFA12）的水平大幅降低，而 CI 组装因子 NDUFAF2 的水平升高。IC/SC 中 CI-Q 模块亚基的水平比 BrSl/CB/CC/HC 中显著降低更多，而其他 OXPHOS 复合物水平未降低。基因本体论和通路分析表明脑区之间存在特定和共同的蛋白质组变化。在所有脑区中，冷休克相关蛋白、线粒体脂肪酸（FA）氧化和合成（mtFAS）的上调最为显著。FA 相关通路在 CB 和 HC 中主要上调。基于这些结果，我们认为刺激这些通路是无效且促病理的，并讨论了 LS 治疗干预的替代策略。意义：Ndufs4 基因敲除小鼠模型是目前研究人类 Leigh 综合征（LS）脑相关病理生理学及干预策略最相关且应用最广泛的动物模型。我们证明 Ndufs4 基因敲除的脑会产生无效且促病理的反应。这些反应解释了 Leigh 综合征小鼠和患者干预研究的阴性和阳性结果，从而为新的干预机会提供指导。
