Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA.
Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA.
Exp Neurol. 2023 Sep;367:114471. doi: 10.1016/j.expneurol.2023.114471. Epub 2023 Jun 14.
Dystonia is a neurological movement disorder characterized by repetitive, unintentional movements and disabling postures that result from sustained or intermittent muscle contractions. The basal ganglia and cerebellum have received substantial focus in studying DYT1 dystonia. It remains unclear how cell-specific ∆GAG mutation of torsinA within specific cells of the basal ganglia or cerebellum affects motor performance, somatosensory network connectivity, and microstructure. In order to achieve this goal, we generated two genetically modified mouse models: in model 1 we performed Dyt1 ∆GAG conditional knock-in (KI) in neurons that express dopamine-2 receptors (D2-KI), and in model 2 we performed Dyt1 ∆GAG conditional KI in Purkinje cells of the cerebellum (Pcp2-KI). In both of these models, we used functional magnetic resonance imaging (fMRI) to assess sensory-evoked brain activation and resting-state functional connectivity, and diffusion MRI to assess brain microstructure. We found that D2-KI mutant mice had motor deficits, abnormal sensory-evoked brain activation in the somatosensory cortex, as well as increased functional connectivity of the anterior medulla with cortex. In contrast, we found that Pcp2-KI mice had improved motor performance, reduced sensory-evoked brain activation in the striatum and midbrain, as well as reduced functional connectivity of the striatum with the anterior medulla. These findings suggest that (1) D2 cell-specific Dyt1 ∆GAG mediated torsinA dysfunction in the basal ganglia results in detrimental effects on the sensorimotor network and motor output, and (2) Purkinje cell-specific Dyt1 ∆GAG mediated torsinA dysfunction in the cerebellum results in compensatory changes in the sensorimotor network that protect against dystonia-like motor deficits.
肌张力障碍是一种以重复、无意识运动和由持续或间歇性肌肉收缩引起的致残姿势为特征的神经运动障碍。基底神经节和小脑在研究 DYT1 肌张力障碍方面受到了广泛关注。目前尚不清楚基底神经节或小脑特定细胞内 torsinA 的细胞特异性 ∆GAG 突变如何影响运动表现、躯体感觉网络连通性和微结构。为了实现这一目标,我们生成了两种基因修饰的小鼠模型:在模型 1 中,我们在表达多巴胺-2 受体(D2-KI)的神经元中进行 Dyt1 ∆GAG 条件敲入(KI),在模型 2 中,我们在小脑浦肯野细胞(Pcp2-KI)中进行 Dyt1 ∆GAG 条件 KI。在这两种模型中,我们都使用功能磁共振成像(fMRI)来评估感觉诱发的大脑激活和静息状态功能连通性,并使用扩散磁共振成像(dMRI)来评估大脑微结构。我们发现 D2-KI 突变小鼠存在运动缺陷、躯体感觉皮层感觉诱发大脑激活异常以及前髓质与皮层的功能连通性增加。相比之下,我们发现 Pcp2-KI 小鼠的运动性能得到改善、纹状体和中脑感觉诱发大脑激活减少以及纹状体与前髓质的功能连通性降低。这些发现表明:(1)基底节中 D2 细胞特异性 Dyt1 ∆GAG 介导的 torsinA 功能障碍导致感觉运动网络和运动输出受损;(2)小脑浦肯野细胞特异性 Dyt1 ∆GAG 介导的 torsinA 功能障碍导致感觉运动网络的代偿性变化,从而防止类似肌张力障碍的运动缺陷。