USP48 alleviates bone cancer pain and regulates MrgC stabilization in spinal cord neurons of male mice.

BACKGROUND: Ubiquitin-mediated degradation of the Mas-related G protein-coupled receptor C (MrgC) reduces the number of receptors. However, the specific deubiquitinating enzyme to antagonize this process has not been reported. In this study, we investigated the effect of ubiquitin-specific protease-48 (USP48) on bone cancer pain and its effect on MrgC.

METHODS: A mouse model of bone cancer pain was established. Bone cancer pain behaviors of mice were assessed after intrathecal injection of AAV (adeno-associated virus)-USP48. USP48 and MrgC interactions were studied by immunoprecipitation. Overexpression and knockdown of USP48 were conducted in N2a cells to investigate the effect of USP48 on MrgC receptor number and ubiquitination.

RESULTS: Spinal cord level USP48 expression was reduced in mice with bone cancer pain. Intrathecal injection of AAV-USP48 increased paw withdrawal mechanical threshold and reduced spontaneous flinching in mice. In N2a cells, there were increased number of MrgC receptors after overexpression of USP48 and decreased number of MrgC receptors after knockdown of USP48. USP48 interacted with MrgC and overexpression of USP48 altered the level of ubiquitination of MrgC.

CONCLUSION: USP48 antagonizes ubiquitin-mediated autophagic degradation of MrgC and alleviates bone cancer pain in a murine animal model. Our findings may provide a new perspective for the treatment of bone cancer pain.