Mechanistic Studies of Cyclooxygenase-2 (COX-2) in Skeletal Muscle Cells During Rotator Cuff Injury: An In Vitro Study

The mechanism of rotator cuff injury remains to be elucidated. And COX-2 plays a dual role in skeletal muscle injury and regeneration, would be associated with the development of rotator cuff injury. Therefore, we chose human skeletal muscle cells (HSKMC) as an in vitro muscle tissue model and transfected lentivirus with overexpressed COX-2 to simulate the in vitro environment of rotator cuff injury. To investigate the specific molecular biological mechanism of COX-2, transcriptome sequencing (RNA-Seq) was used to analyze the differentially expressed mRNAs in HSKMC overexpressing COX-2. Enrichment analysis was performed to analyze these differentially expressed genes and real-time quantitative PCR (RT-qPCR) was used to examine the mRNA levels of genes induced by overexpression. Subsequently, the role of COX-2 in cell proliferation was confirmed by cell counting kit-8 (CCK-8), and focal adhesion kinase (FAK) and signal transducer and activator of transcription 3 (STAT3) phosphorylation induced by COX-2 was utilized by western blotting (WB). The results showed that total of 30,759 differentially expressed genes were obtained, and the expression of CYP4F3 and GPR87 was significantly increased. COX-2 could bind CYP4F3 and GPR87 and co-localize with them in the cytoplasm. Finally, COX-2 promoted the proliferation of human skeletal muscle cells by activating the FAK and STAT3 pathways.