Activated Fibroblast Growth Factor Receptor 1 Mitigated Poly-PR-Induced Oxidative Stress and Protein Translational Impairment.

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by selective motor neuron cell death. A GGGGCC hexanucleotide repeat expansion (HRE) within the chromosome 9 open reading frame 72 (C9orf72) gene is a major causative factor in ALS. This abnormal HRE triggers five types of dipeptide repeat protein (DPR), each composed of two alternating amino acid expressions. Among the DPRs, arginine-rich Poly-PR localizes predominantly to the nucleus, exerting particularly strong toxicity on motor and cortical neurons. Several mechanisms have been proposed for poly-PR-induced neurotoxicity. In this study, poly-PR-expressing NSC34 motor neuron-like cells showed an increase in oxidative stress. Fibroblast growth factor receptor 1 (FGFR1) is known to promote neurogenesis and inhibit apoptosis in neurons. However, its neuroprotective effects against DPR-induced toxicity have not been previously reported. Here, we demonstrated that FGFR1 activation reduced oxidative stress by upregulating nuclear factor erythroid 2-related factor 2 (NRF2) expression. Furthermore, we propose that the increase in NRF2 through FGFR1 activation may result from the alleviation of protein translation impairment. Overall, these findings suggest that FGFR1 activation provides neuroprotection against poly-PR toxicity and may represent a potential therapeutic strategy for ALS.