The potential value of microRNA-409-5p-mediated negative regulation of USP7 in the diagnosis and treatment of acute myocardial infarction.

PURPOSE: This study aimed to explore the effects of ubiquitin-specific peptidase 7 (USP7) on acute myocardial infarction (AMI) and the negative regulation of USP7 by microRNA-409-5p (miR-409-5p). METHODS: Clinical data were collected from patients admitted to the Cardiology Department of Yan'an Hospital of Kunming City between July 2020 and July 2021. The participants included patients with AMI (AMI; n = 30), stable angina pectoris (SAP; n = 30), and chest pain syndrome (CPS; n = 30) and healthy controls (n = 30). The expression levels of miR-409-5p and USP7 were analysed using Quantitative real-time polymerase chain reaction (qRT‒PCR) and Western blotting (WB). Finally, a dual-luciferase assay was performed to verify the interaction between miR-409-5p and USP7. RESULTS: The expression level of miR-409-5p was significantly lower (all p < 0.05), whereas the expression level of USP7 was elevated in patients with AMI compared with those in the other three groups (all p < 0.05). A dual-luciferase assay demonstrated that miR-409-5p binds to USP7 3'UTP to inhibit luciferase expression. Compared with cells transfected with mutation fragments and a luciferase reporter vector with microRNA-409-5p mimics and USP7 3'UTR binding and mutation sites, the luminescence level of cells with miR-409-5p was approximately 40% lower. Additionally, miRNA-409-5p was inversely correlated with cTnI (p = 0.004). CONCLUSION: USP7 plays a significant role in AMI via negative regulation by miR-409-5p. Both miR-409-5p and USP7 hold key potential as early diagnostic biomarkers and therapeutic targets for AMI in the future.