VCP, a Major ATPase in the Cells, as a Novel Drug Target for Currently Incurable Disorders

Neuroprotection would be a novel therapeutic strategy for the prevention or retardation of clinical manifestations of currently incurable eye diseases as well as neurodegenerative diseases. A decrease in cellular ATP levels may contribute to the pathologies of these diseases; therefore, stabilization of ATP levels may retard the disease progression. We created novel small compounds (Kyoto University Substances, KUSs) to inhibit the ATPase activity of VCP (valosin-containing protein), the most abundant soluble ATPase in the cell. KUSs did not apparently impair the reported cellular VCP functions. Nevertheless, they significantly suppressed the VCP-dependent decrease of cellular ATP levels. Moreover, KUSs as well as exogenous ATP or ATP-producing compounds suppressed endoplasmic reticulum (ER) stress, and indeed protected various types of cultured cells from cell death-inducing insults. We then examined the efficacies of KUSs in rd10, a mouse model of retinitis pigmentosa. KUSs not only prevented photoreceptor cell death but also preserved visual function. These results reveal an unexpected, crucial role of ATP consumption by VCP for the determination of cell fate in the pathological context, and point to a promising new neuroprotective strategy for currently incurable eye and neurodegenerative diseases.