USP2 alleviates MPP⁺-induced neuronal injury by stabilizing FOXC1 in SK-N-SH cells

Forkhead box transcription factors play a crucial role in the development of various organ systems, and exhibit neuroprotective properties in many neurodegenerative diseases, including Parkinson's disease (PD). However, the role and mechanism of Forkhead box C1 (FOXC1) in the pathogenesis of PD is poorly defined.

Human neuroblastoma SK-N-SH cells were treated with 1-methyl-4-phenylpyridinium (MPP⁺) to establish an in vitro model of PD. FOXC1 and Ubiquitin-specific peptidase 2 (USP2) mRNA levels were detected using real-time quantitative polymerase chain reaction (RT-qPCR). FOXC1, B-cell lymphoma-2 (Bcl-2), Bcl-2 related X protein (Bax), Cleaved caspase-3, and USP2 protein levels were determined using Western blot. Cell viability and apoptosis were analyzed using CCK-8 assay and flow cytometry. Tumor necrosis factor α (TNF-α), Interleukin-1β (IL-1β), and IL-6 levels were analyzed using ELISA. Reactive oxygen species (ROS), malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), and Glutathione (GSH) products were examined using special assay kits. After Ubibrowser online database prediction, the interaction between USP2 and FOXC1 was verified using Co-immunoprecipitation (CoIP) assay.

FOXC1 and USP2 expression were decreased in PD patients and MPP⁺-treated SK-N-SH cells. MPP⁺ treatment could elicit SK-N-SH cell viability inhibition, inflammatory response, oxidative stress, and apoptosis promotion in vitro. Furthermore, overexpressing FOXC1 relieved MPP⁺-induced SK-N-SH cell injury in vitro. Mechanistically, USP2 directly interacted with FOXC1 and deubiquitinated FOXC1, therefore enhancing FOXC1 protein stability.

USP2 attenuated MPP⁺-triggered SK-N-SH cell injury through stabilizing FOXC1, providing a promising therapeutic target for PD treatment.