Research Unit for Molecular Medicine, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark; Department of Clinical Biochemistry, Aarhus University Hospital, Aarhus, Denmark.
Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark.
Mol Metab. 2024 Oct;88:102009. doi: 10.1016/j.molmet.2024.102009. Epub 2024 Aug 14.
Mitochondrial proteostasis is critical for cellular function. The molecular chaperone HSP60 is essential for cell function and dysregulation of HSP60 expression has been implicated in cancer and diabetes. The few reported patients carrying HSP60 gene variants show neurodevelopmental delay and brain hypomyelination. Hsp60 interacts with more than 260 mitochondrial proteins but the mitochondrial proteins and functions affected by HSP60 deficiency are poorly characterized.
We studied two model systems for HSP60 deficiency: (1) engineered HEK cells carrying an inducible dominant negative HSP60 mutant protein, (2) zebrafish HSP60 knockout larvae. Both systems were analyzed by RNASeq, proteomics, and targeted metabolomics, and several functional assays relevant for the respective model. In addition, skin fibroblasts from patients with disease-associated HSP60 variants were analyzed by proteomics.
We show that HSP60 deficiency leads to a differentially downregulated mitochondrial matrix proteome, transcriptional activation of stress responses, and dysregulated cholesterol biosynthesis. This leads to lipid accumulation in zebrafish knockout larvae.
Our data provide a compendium of the effects of HSP60 deficiency on the mitochondrial matrix proteome. We show that HSP60 is a master regulator and modulator of mitochondrial functions and metabolic pathways. HSP60 dysfunction also affects cellular metabolism and disrupts the integrated stress response. The effect on cholesterol synthesis explains the effect of HSP60 dysfunction on myelination observed in patients carrying genetic variants of HSP60.
线粒体蛋白质稳态对细胞功能至关重要。分子伴侣 HSP60 是细胞功能所必需的，HSP60 表达的失调与癌症和糖尿病有关。少数报道的携带 HSP60 基因突变的患者表现出神经发育迟缓伴脑髓鞘发育不良。Hsp60 与 260 多种线粒体蛋白相互作用，但 HSP60 缺乏对线粒体蛋白和功能的影响尚未得到很好的描述。
我们研究了 HSP60 缺乏的两种模型系统：（1）携带诱导型显性负性 HSP60 突变蛋白的工程化 HEK 细胞，（2）HSP60 敲除的斑马鱼幼虫。通过 RNAseq、蛋白质组学和靶向代谢组学以及与各自模型相关的几种功能测定对这两种系统进行了分析。此外，还通过蛋白质组学分析了与疾病相关的 HSP60 变体的患者皮肤成纤维细胞。
我们表明，HSP60 缺乏导致线粒体基质蛋白质组的差异下调、应激反应的转录激活和胆固醇生物合成的失调。这导致斑马鱼敲除幼虫中的脂质积累。
我们的数据提供了 HSP60 缺乏对线粒体基质蛋白质组影响的概述。我们表明，HSP60 是线粒体功能和代谢途径的主调节因子和调节剂。HSP60 功能障碍还会影响细胞代谢并破坏整合应激反应。胆固醇合成的影响解释了携带 HSP60 基因突变的患者中 HSP60 功能障碍对髓鞘形成的影响。
