MiR-21-5p promotes differentiation and reduces oleic acid-induced lipid droplet accumulation in C2C12 myoblasts by targeting FBXO11.

Objective: This study aimed to investigate the function of miRNA 21-5p in regulating the differentiation of C2C12 myoblasts and intramuscular lipid droplet accumulation in myotubes.

Methods: The role of miR-21-5p in the proliferation and differentiation of myofibroblasts and intracellular lipid accumulation was analyzed using bioinformatics, CCK-8 assay, RT-qPCR, immunoblotting, immunofluorescence staining, and Oil Red O staining.

Results: Analysis of porcine BodyMap transcriptomic data revealed differential expression of miRNA 21-5p in skeletal muscle and adipose tissue. Bioinformatics analysis combined with a dual-luciferase reporter assay demonstrated that FBXO11 serves as a direct target of miR-21-5p. Transfection experiments involving a miR-21-5p mimic, miR-21-5p inhibitor, and si-FBXO11 in C2C12 cells showed that overexpression of miR-21-5p or silencing of FBXO11 significantly enhanced the proliferation of C2C12 cells, upregulated myogenesis-related factors, and promoted myotube formation. Additionally, oleic acid-induced lipid accumulation in myotubes was suppressed, accompanied by reduced expression of adipogenesis-related genes. Conversely, inhibition of miR-21-5p expression produced opposite effects.

Conclusion: These findings indicate that miR-21-5p promotes proliferation and differentiation while inhibiting intramyocellular lipid deposition by targeting the 3'-untranslated region (3'UTR) of FBXO11 in myogenic cell. The results suggest that miR-21-5p could serve as a potential miRNA biomarker for regulating intramuscular adipogenesis.