Liou Benjamin, Peng Yanyan, Li Ronghua, Inskeep Venette, Zhang Wujuan, Quinn Brian, Dasgupta Nupur, Blackwood Rachel, Setchell Kenneth D R, Fleming Sheila, Grabowski Gregory A, Marshall John, Sun Ying
Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA.
Division of Pathology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA.
Hum Mol Genet. 2016 Dec 1;25(23):5126-5141. doi: 10.1093/hmg/ddw322.
Neuronopathic Gaucher disease (nGD) manifests as severe neurological symptoms in patients with no effective treatment available. Ryanodine receptors (Ryrs) are a family of calcium release channels on intracellular stores. The goal of this study is to determine if Ryrs are potential targets for nGD treatment. A nGD cell model (CBE-N2a) was created by inhibiting acid β-glucosidase (GCase) in N2a cells with conduritol B epoxide (CBE). Enhanced cytosolic calcium in CBE-N2a cells was blocked by either ryanodine or dantrolene, antagonists of Ryrs and by Genz-161, a glucosylceramide synthase inhibitor, suggesting substrate-mediated ER-calcium efflux occurs through ryanodine receptors. In the brain of a nGD (4L;C*) mouse model, expression of Ryrs was normal at 13 days of age, but significantly decreased below the wild type level in end-stage 4L;C* brains at 40 days. Treatment with dantrolene in 4L;C* mice starting at postnatal day 5 delayed neurological pathology and prolonged survival. Compared to untreated 4L;C* mice, dantrolene treatment significantly improved gait, reduced LC3-II levels, improved mitochondrial ATP production and reduced inflammation in the brain. Dantrolene treatment partially normalized Ryr expression and its potential regulators, CAMK IV and calmodulin. Furthermore, dantrolene treatment increased residual mutant GCase activity in 4L;C* brains. These data demonstrate that modulating Ryrs has neuroprotective effects in nGD through mechanisms that protect the mitochondria, autophagy, Ryr expression and enhance GCase activity. This study suggests that calcium signalling stabilization, e.g. with dantrolene, could be a potential disease modifying therapy for nGD.
神经元型戈谢病（nGD）在患者中表现为严重的神经症状，目前尚无有效的治疗方法。兰尼碱受体（Ryrs）是细胞内储存上的一类钙释放通道。本研究的目的是确定Ryrs是否为nGD治疗的潜在靶点。通过用环氧CONDURITOL B（CBE）抑制N2a细胞中的酸性β-葡萄糖苷酶（GCase），创建了nGD细胞模型（CBE-N2a）。兰尼碱或丹曲林（Ryrs的拮抗剂）以及葡萄糖神经酰胺合酶抑制剂Genz-161均可阻断CBE-N2a细胞中增强的胞质钙，这表明底物介导的内质网钙外流通过兰尼碱受体发生。在nGD（4L；C*）小鼠模型的大脑中，Ryrs的表达在13日龄时正常，但在40日龄的晚期4L；C大脑中显著低于野生型水平。从出生后第5天开始用丹曲林治疗4L；C小鼠，可延迟神经病理学并延长生存期。与未治疗的4L；C小鼠相比，丹曲林治疗显著改善了步态，降低了LC3-II水平，改善了线粒体ATP生成并减轻了大脑炎症。丹曲林治疗使Ryr表达及其潜在调节因子钙/钙调蛋白依赖性蛋白激酶IV（CAMK IV）和钙调蛋白部分恢复正常。此外，丹曲林治疗增加了4L；C大脑中残余的突变型GCase活性。这些数据表明，调节Ryrs在nGD中具有神经保护作用，其机制包括保护线粒体、自噬、Ryr表达并增强GCase活性。本研究表明，例如用丹曲林稳定钙信号可能是一种潜在的nGD疾病修饰疗法。
