FDA-approved PDE4 inhibitors reduce the dominant toxicity of ALS–FTD-associatedCHCHD10S59L

ABSTRACT Mutations in coiled-coil-helix-coiled-coil-helix domain containing 10(CHCHD10) have been identified as a genetic cause of amyotrophic lateral sclerosis and/or frontotemporal dementia(ALS-FTD). In our previous studies using in vivo Drosophila model expressing C2C10HS81L, and human cell models expressing CHCHD10S59L, we have identified that the PINK1/Parkin pathway is activated and causes cellular toxicity. Furthermore, we demonstrated that pseudo-substrate inhibitors for PINK1 and mitofusin2 agonists mitigated the cellular toxicity of CHCHD10S59L. Evidences using in vitro/ in vivo genetic and chemical tools indicate that inhibiting PINK1 would be the most promising treatment for CHCHD10S59L-induced diseases. Therefore, we have investigated cellular pathways that can modulate the PINK1/Parkin pathway and reduce CHCHD10S59L-induced cytotoxicity. Here, we report that FDA-approved PDE4 inhibitors reduced CHCHD10S59L-induced morphological and functional mitochondrial defects in human cells and an in vivo Drosophila model expressing C2C10HS81L. Multiple PDE4 inhibitors decreased PINK1 accumulation and downstream mitophagy induced by CHCHD10S59L. These findings suggest that PDE4 inhibitors currently available in the market may be repositioned to treat CHCHD10S59L-induced ALS-FTD and possibly other related diseases. Competing Interest Statement The authors have declared no competing interest.