Urolithin A improves motor dysfunction induced by copper exposure in SOD1 G93A transgenic mice via activation of mitophagy

Abstract

Aim Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease pathologically characterized by selective degeneration of motor neurons resulting in a catastrophic loss of motor function. The present study aimed to investigate the effect of copper (Cu) exposure on progression of ALS and explore the therapeutic effect and mechanism of Urolithin A (UA) on ALS. Methods 0.13 PPM copper chloride drinking water was administrated in SOD1^G93A transgenic mice at 6 weeks, UA at a dosage of 50 mg/kg/day was given for 6 weeks after a 7-week Cu exposure. Motor ability was assessed before terminal anesthesia. Muscle atrophy and fibrosis, motor neurons, astrocytes and microglia in the spinal cord were evaluated by H&E, Masson, Sirius Red, Nissl and Immunohistochemistry Staining. Proteomics analysis, Western blotting and ELISA were conducted to detect protein expression. Mitochondrial adenosine triphosphate (ATP) and malondialdehyde (MDA) levels were measured using an assay kit. Results Cu-exposure worsened motor function, promoted muscle fibrosis, loss of motor neurons, and astrocyte and microglial activation. It also induced abnormal changes in mitochondria-related biological processes, leading to a significant reduction in ATP levels and an increase in MDA levels. Upregulation of P62 and downregulation of Parkin, PINK1, and LAMP1 were revealed in SOD1^G93A mice with Cu exposure. Administration of UA activated mitophagy, modulated mitochondria dysfunction, reduced neuroinflammation, and improved gastrocnemius muscle atrophy and motor dysfunction in SOD1^G93A mice with Cu exposure. Conclusions Mitophagy plays critical role in ALS exacerbated by Cu exposure. UA administration may be a promising treatment strategy for ALS.