Leu promotes C2C12 cell differentiation by regulating the GSK3β/β-catenin signaling pathway through facilitating the interaction between SESN2 and RPN2.

BACKGROUND: Leucine (Leu), an essential amino acid that facilitated skeletal muscle satellite cell differentiation, yet its mechanism remained underexplored. Sestrin2 (SESN2) served as a Leu sensor, binding directly to Leu, while Riboprotein II (RPN2) acted as a signaling factor in multiple pathways. This study aimed to elucidate Leu's impact on mouse C2C12 cell differentiation and skeletal muscle injury repair by modulating RPN2 expression through SESN2, offering a theoretical foundation for clinical skeletal muscle injury prevention and treatment.

RESULTS: Leu addition promoted C2C12 cell differentiation compared to the control, enhancing early differentiation via MYOD up-regulation. Sequencing revealed SESN2 binding to and interacting with RPN2. RPN2 overexpression up-regulated MYOD, MYOG, and MYH2, concurrently decreased p-GSK3β, and increased nuclear β-catenin. Conversely, RPN2 knockdown yielded opposite results. Combining RPN2 knockdown with Leu rescued increased p-GSK3β and decreased nuclear β-catenin compared to Leu absence. HE staining results showed that Leu addition accelerated mouse muscle damage repair, up-regulating Pax7, MYOD, and RPN2 in the cytoplasm, and nuclear β-catenin, confirmed that the role of Leu's in muscle injury repair was consistent with the results in C2C12 cell.

CONCLUSION: Leu, bound with SESN2, up-regulated RPN2 expression, activated the GSK3β/β-catenin pathway, enhanced C2C12 differentiation, and expedited skeletal muscle damage repair. This article is protected by copyright. All rights reserved.