Therapeutic modulation of GSTO activity rescues FUS-associated neurotoxicity via deglutathionylation in ALS disease models

Fused in sarcoma (FUS) is a DNA/RNA-binding protein that is involved in DNA repair and RNA processing. FUS is associated with neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). However, the molecular mechanisms underlying FUS-mediated neurodegeneration are largely unknown. Here, using a Drosophila model, we showed that the overexpression of glutathione transferase omega 2 (GstO2) reduces cytoplasmic FUS aggregates and prevents neurodegenerative phenotypes, including neurotoxicity and mitochondrial dysfunction. We found a FUS glutathionylation site at the 447th cysteine residue in the RanBP2-type ZnF domain. The glutathionylation of FUS induces FUS aggregation by promoting phase separation. GstO2 reduced cytoplasmic FUS aggregation by deglutathionylation in Drosophila brains. Moreover, we demonstrated that the overexpression of human GSTO1, the homolog of Drosophila GstO2, attenuates FUS-induced neurotoxicity and cytoplasmic FUS accumulation in mouse neuronal cells. Thus, the modulation of FUS glutathionylation might be a promising therapeutic strategy for FUS-associated neurodegenerative diseases. [Display omitted] •GSTO suppresses FUS-induced neurotoxicity•GSTO inhibits the formation of cytoplasmic FUS aggregates in neurons•Glutathionylation decreases FUS solubility by promoting phase separation•GSTO regulates FUS liquid-liquid phase separation by reducing glutathionylation in vivo Fused in sarcoma (FUS) is genetically linked to amyotrophic lateral sclerosis and frontotemporal dementia. Cha and Lee et al. report that FUS glutathionylation promotes liquid-liquid phase separation and aggregate formation in vitro. Glutathione transferase omega activation mitigates cytoplasmic FUS aggregation by deglutathionylation in vivo.