Modeling sporadic juvenile ALS in iPSC-derived motor neurons explores the pathogenesis of FUSR503fs mutation

Li Chen; Guojie Chen; Mengting Zhang; Xiaojie Zhang

doi:10.3389/fncel.2024.1364164

Modeling sporadic juvenile ALS in iPSC-derived motor neurons explores the pathogenesis of FUS^R503fs mutation

Front Cell Neurosci. 2024 Apr 22:18:1364164. doi: 10.3389/fncel.2024.1364164. eCollection 2024.

Authors

Li Chen^{1

2}, Guojie Chen³, Mengting Zhang⁴, Xiaojie Zhang^{1

2}

Affiliations

¹ Department of Neurology, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China.
² Shanghai Neurological Rare Disease Biobank and Precision Diagnostic Technical Service Platform, Shanghai, China.
³ Hunan YoBon Biotechnology Limited Company, Changsha, Hunan, China.
⁴ College of Integrated Chinese and Western Medicine (School of Life Sciences), Anhui University of Chinese Medicine, Hefei, Anhui, China.

Abstract

Introduction: Fused in sarcoma (FUS) mutations represent the most common genetic etiology of juvenile amyotrophic lateral sclerosis (JALS), for which effective treatments are lacking. In a prior report, we identified a novel FUS mutation, c.1509dupA: p. R503fs (FUSR503fs), in a sporadic JALS patient.

Methods: The physicochemical properties and structure of FUSR503fs protein were analyzed by software: Multi-electrode array (MEA) assay, calcium activity imaging assay and transcriptome analysis were used to explore the pathophysiological mechanism of iPSC derived motor neurons.

Results: Structural analysis and predictions regarding physical and chemical properties of this mutation suggest that the reduction of phosphorylation and glycosylation sites, along with alterations in the amino acid sequence, may contribute to abnormal FUS accumulation within the cytoplasm and nucleus of induced pluripotent stem cell- derived motor neurons (MNs). Multi-electrode array and calcium activity imaging indicate diminished spontaneous electrical and calcium activity signals in MNs harboring the FUS^R503fs mutation. Transcriptomic analysis reveals upregulation of genes associated with viral infection and downregulation of genes involved in neural function maintenance, such as the ATP6V1C2 gene. Treatment with ropinirole marginally mitigates the electrophysiological decline in FUS^R503fs MNs, suggesting the utility of this cell model for mechanistic exploration and drug screening.

Discussion: iPSCs-derived motor neurons from JALS patients are promising tools for drug screening. The pathological changes in motor neurons of FUS^R503fs may occur earlier than in other known mutation types that have been reported.

Keywords: calcium activity imaging; fused in sarcoma; juvenile amyotrophic lateral sclerosis; neuroelectrophysiology; physicochemical properties.

Grants and funding

The author(s) declare that financial support was received for the research, authorship, and/or publication of this article. This study was supported by the program of the National Natural Science Foundation of China (LC, NO. 82101483).