MiR-34a-5p promotes skeletal muscle atrophy by targeting LGR4 and the RANK/NF-κB pathway in diabetic mice

Background Muscle atrophy is more common in individuals with diabetes, but research in this area is limited. This study aims to investigate the molecular mechanisms of diabetic muscle atrophy using RNA sequencing (RNA-Seq) of the gastrocnemius muscle (GM). Methods Streptozotocin (STZ)-induced diabetic mice were used to study muscle atrophy. Bioinformatics analyses identified differentially expressed genes (DEGs) and candidate miRNAs. Hub genes and miR-34a-5p were validated by RT-qPCR. The role of miR-34a-5p in the RANK/NF-κB pathway was examined using TargetScan, dual-luciferase assays, miR-34a-5p mimics, and inhibitors in C2C12 myotubes under high glucose. Results Diabetic mice showed reduced grip strength, GM mass, and muscle fiber cross-sectional area compared to controls. Markers of muscle atrophy, Atrogin-1, and MuRF-1, were elevated in diabetic mice. RNA-Seq identified 821 DEGs related to muscle atrophy, involved in processes like ion transport, transmembrane transport, lipid response, and IL-17 signaling. Gene Set Enrichment Analysis highlighted TNFA signaling via NFKB in GM. Hub genes Foxo1, IL-1β, TLR-4, and TNF were identified. miR-34a-5p was implicated in diabetic muscle atrophy. LGR4 expression was reduced in high glucose-exposed C2C12 myotubes and diabetic mice GM, while RANK and NF-κB levels were increased. LGR4 was confirmed as a target of miR-34a-5p. miR-34a-5p mimics decreased LGR4 and increased RANK, NF-κB, Atrogin-1, and MuRF-1 levels, effects reversed by miR-34a-5p inhibitors. Conclusion Foxo1, IL-1β, TLR-4, and TNF are key genes in diabetic muscle atrophy. miR-34a-5p targets LGR4, activating the RANK/NF-κB pathway and contributing to muscle atrophy. These findings offer potential intervention targets for diabetic muscle atrophy.