Antisense oligonucleotides targeting Valosin-containing protein improve muscle pathology and molecular defects in cell and mouse models of multisystem proteinopathy

Valosin-containing protein (VCP) related disease, also known as multisystem proteinopathy 1 (MSP1), is an autosomal dominant disease caused by gain-of-function pathogenic variants of the VCP gene. The disease is associated with inclusion body myopathy, early-onset Paget’s disease of bone, frontotemporal dementia, and familial amyotrophic lateral sclerosis. There is currently no treatment for this progressive disease associated with early demise resulting from proximal limb girdle and respiratory muscle weakness. We hypothesize that regulating VCP hyperactivity to normal levels can reduce the disease pathology. In this study, we assessed the effect of antisense oligonucleotides (ASOs) specifically targeting the human VCP gene in the patient (R155H) iPSC-derived skeletal muscle progenitor cells (SMPCs). ASOs were well tolerated up to a concentration of 5 µM, and significantly reduced VCP protein expression in the SMPCs by 48% (95% CI [39–56]). We also treated the transgenic mouse model of VCP disease with the overexpressed humanized VCP gene severe A232E pathogenic variant with weekly subcutaneous ASO injections starting from 6 months of age for 3 months. In the skeletal muscle of transgenic mice, ASOs resulted in 30% (95%CI [27–32]) knockdown of VCP protein compared to control ASO. The ASO-mediated reduction of VCP expression in muscle tissue was associated with improvement in autophagy flux and reduction in TDP-43 expression, hallmarks of VCP disease. In addition, ASO-treated VCP A232E mice showed improvements in functional tests of muscle strength, such as rotarod and inverted screen test compared to mice treated with control ASO. These results suggest that targeting VCP could be beneficial in preventing the progression of the VCP myopathy and hold promise for the treatment of patients with VCP MSP1.