Department of Pharmacology & Toxicology, Michigan State University, East Lansing, MI, United States of America.
College of Veterinary Medicine, Michigan State University, East Lansing, MI, United States of America.
PLoS One. 2019 Jan 25;14(1):e0211066. doi: 10.1371/journal.pone.0211066. eCollection 2019.
Infants and children with dominant de novo mutations in GNAO1 exhibit movement disorders, epilepsy, or both. Children with loss-of-function (LOF) mutations exhibit Epileptiform Encephalopathy 17 (EIEE17). Gain-of-function (GOF) mutations or those with normal function are found in patients with Neurodevelopmental Disorder with Involuntary Movements (NEDIM). There is no animal model with a human mutant GNAO1 allele.
Here we develop a mouse model carrying a human GNAO1 mutation (G203R) and determine whether the clinical features of patients with this GNAO1 mutation, which includes both epilepsy and movement disorder, would be evident in the mouse model.
A mouse Gnao1 knock-in GOF mutation (G203R) was created by CRISPR/Cas9 methods. The resulting offspring and littermate controls were subjected to a battery of behavioral tests. A previously reported GOF mutant mouse knock-in (Gnao1+/G184S), which has not been found in patients, was also studied for comparison.
Gnao1+/G203R mutant mice are viable and gain weight comparably to controls. Homozygotes are non-viable. Grip strength was decreased in both males and females. Male Gnao1+/G203R mice were strongly affected in movement assays (RotaRod and DigiGait) while females were not. Male Gnao1+/G203R mice also showed enhanced seizure propensity in the pentylenetetrazole kindling test. Mice with a G184S GOF knock-in also showed movement-related behavioral phenotypes but females were more strongly affected than males.
Gnao1+/G203R mice phenocopy children with heterozygous GNAO1 G203R mutations, showing both movement disorder and a relatively mild epilepsy pattern. This mouse model should be useful in mechanistic and preclinical studies of GNAO1-related movement disorders.
具有 GNAO1 显性新生突变的婴儿和儿童表现为运动障碍、癫痫或两者兼有。具有功能丧失（LOF）突变的儿童表现为癫痫性脑病 17 型（EIEE17）。获得功能（GOF）突变或具有正常功能的突变存在于伴有不自主运动的神经发育障碍（NEDIM）患者中。目前还没有携带人类突变 GNAO1 等位基因的动物模型。
本研究构建了携带人类 GNAO1 突变（G203R）的小鼠模型，并确定该 GNAO1 突变患者的临床特征，包括癫痫和运动障碍，是否会在该小鼠模型中显现。
通过 CRISPR/Cas9 方法构建了小鼠 Gnao1 基因敲入 GOF 突变（G203R）。对所得后代及其同窝对照进行了一系列行为测试。还研究了之前报道的 GOF 突变体小鼠敲入（Gnao1+/G184S），该突变在患者中尚未发现，作为对照。
Gnao1+/G203R 突变小鼠是可行的，体重增长与对照组相当。纯合子是不可行的。雄性和雌性的握力都降低了。雄性 Gnao1+/G203R 小鼠在旋转棒和 Digigait 运动测试中受到强烈影响，而雌性小鼠则没有。雄性 Gnao1+/G203R 小鼠在戊四氮点燃试验中也表现出增强的癫痫易感性。具有 G184S GOF 敲入的小鼠也表现出与运动相关的行为表型，但雌性比雄性受影响更严重。
Gnao1+/G203R 小鼠模拟杂合 GNAO1 G203R 突变儿童，表现为运动障碍和相对较轻的癫痫模式。该小鼠模型应可用于 GNAO1 相关运动障碍的机制和临床前研究。
