Nan-Xiang Shen, Xiao-Chong Qu, Jing Yu, Cui-Xia Fan, Fu-Li Min, Ling-Ying Li, Ming-Rui Zhang, Bing-Mei Li, Jie Wang, Na He, Wei-Ping Liao, Yi-Wu Shi, Wen-Bin Li
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引用次数: 0
Abstract
NUS1 encodes the Nogo-B receptor, a critical regulator for unfolded protein reaction (UPR) signaling. Although several loss-of-function variants of NUS1 have been identified in patients with developmental and epileptic encephalopathy (DEE), the role of the NUS1 variant in Lennox-Gastaut syndrome (LGS), a severe child-onset DEE, remains unknown. In this study, we identified two de novo variants of NUS1, a missense variant (c.868 C > T/p.R290C) and a splice site variant (c.792-2 A > G), in two unrelated LGS patients using trio-based whole-exome sequencing performed in a cohort of 165 LGS patients. Both variants were absent in the gnomAD population and showed a significantly higher observed number of variants than expected genome-wide. The R290C variant was predicted to damage NUS1 and decrease its protein stability. The c.792-2 A > G variant caused premature termination of the protein. Knockdown of NUS1 activated the UPR pathway, resulting in apoptosis of HEK293T cells. Supplementing cells with expression of wild-type NUS1, but not the mutant (R290C), rescued UPR activation and apoptosis in NUS1 knockdown cells. Compared to wild-type Drosophila, seizure-like behaviors and excitability in projection neurons were significantly increased in Tango14 (homolog of human NUS1) knockdown and Tango14R290C/+ knock-in Drosophila. Additionally, abnormal development and a small body size were observed in both mutants. Activated UPR signaling was also detected in both mutants. Thus, NUS1 is a causative gene for LGS with dominant inheritance. The pathogenicity of these variants is related to the UPR signaling activation, which may be a common pathogenic mechanism of DEE.
期刊介绍:
Molecular Neurobiology is an exciting journal for neuroscientists needing to stay in close touch with progress at the forefront of molecular brain research today. It is an especially important periodical for graduate students and "postdocs," specifically designed to synthesize and critically assess research trends for all neuroscientists hoping to stay active at the cutting edge of this dramatically developing area. This journal has proven to be crucial in departmental libraries, serving as essential reading for every committed neuroscientist who is striving to keep abreast of all rapid developments in a forefront field. Most recent significant advances in experimental and clinical neuroscience have been occurring at the molecular level. Until now, there has been no journal devoted to looking closely at this fragmented literature in a critical, coherent fashion. Each submission is thoroughly analyzed by scientists and clinicians internationally renowned for their special competence in the areas treated.