Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA; The Collaborative Center for X-Linked Dystonia-Parkinsonism, Department of Neurology, Massachusetts General Hospital, Charlestown, MA 02129, USA; Program in Medical and Population Genetics and Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA.
The Collaborative Center for X-Linked Dystonia-Parkinsonism, Department of Neurology, Massachusetts General Hospital, Charlestown, MA 02129, USA.
Am J Hum Genet. 2021 Nov 4;108(11):2145-2158. doi: 10.1016/j.ajhg.2021.09.017. Epub 2021 Oct 20.
Dystonia is a neurologic disorder associated with an increasingly large number of genetic variants in many genes, resulting in characteristic disturbances in volitional movement. Dissecting the relationships between these mutations and their functional outcomes is critical in understanding the pathways that drive dystonia pathogenesis. Here we established a pipeline for characterizing an allelic series of dystonia-specific mutations. We used this strategy to investigate the molecular consequences of genetic variation in THAP1, which encodes a transcription factor linked to neural differentiation. Multiple pathogenic mutations associated with dystonia cluster within distinct THAP1 functional domains and are predicted to alter DNA-binding properties and/or protein interactions differently, yet the relative impact of these varied changes on molecular signatures and neural deficits is unclear. To determine the effects of these mutations on THAP1 transcriptional activity, we engineered an allelic series of eight alterations in a common induced pluripotent stem cell background and differentiated these lines into a panel of near-isogenic neural stem cells (n = 94 lines). Transcriptome profiling followed by joint analysis of the most robust signatures across mutations identified a convergent pattern of dysregulated genes functionally related to neurodevelopment, lysosomal lipid metabolism, and myelin. On the basis of these observations, we examined mice bearing Thap1-disruptive alleles and detected significant changes in myelin gene expression and reduction of myelin structural integrity relative to control mice. These results suggest that deficits in neurodevelopment and myelination are common consequences of dystonia-associated THAP1 mutations and highlight the potential role of neuron-glial interactions in the pathogenesis of dystonia.
肌张力障碍是一种与越来越多的基因突变相关的神经疾病，这些基因突变存在于许多基因中，导致随意运动的特征性紊乱。解析这些突变与它们的功能后果之间的关系，对于理解导致肌张力障碍发病机制的途径至关重要。在这里，我们建立了一个用于描述一系列特定于肌张力障碍的突变等位基因的方案。我们使用这种策略来研究编码与神经分化相关的转录因子的 THAP1 中的遗传变异的分子后果。与肌张力障碍相关的多种致病性突变聚集在 THAP1 的不同功能域内，预计会以不同的方式改变 DNA 结合特性和/或蛋白相互作用，但这些不同变化对分子特征和神经缺陷的相对影响尚不清楚。为了确定这些突变对 THAP1 转录活性的影响，我们在常见的诱导多能干细胞背景中设计了一个等位基因系列的八种改变，并将这些细胞系分化为一组近同基因神经干细胞（n = 94 个细胞系）。对突变最显著的转录组谱进行分析后，我们确定了一个功能上与神经发育、溶酶体脂质代谢和髓鞘相关的失调基因的收敛模式。基于这些观察结果，我们检查了携带 Thap1 破坏等位基因的小鼠，并发现与对照小鼠相比，髓鞘基因表达和髓鞘结构完整性有显著变化。这些结果表明，神经发育和髓鞘形成缺陷是与肌张力障碍相关的 THAP1 突变的常见后果，并强调了神经元-胶质相互作用在肌张力障碍发病机制中的潜在作用。
