LETM2 regulates mitochondrial function and autophagy in diabetic foot ulcers: implications for oxidative stress and therapeutic targeting

Background A major complication of diabetes, diabetic foot ulcers (DFU), has been linked to mitochondrial dysfunction and oxidative stress. Here, we performed analysis of RNA sequencing data from publicly available databases, including single-cell assays, to identify dysregulated genes associated with these processes in DFU and the specific cell types involved. Methods Analysis of transcriptome sequencing was performed on GSE134431 and GSE80178 datasets from the GEO database to identify differentially expressed mitochondrial-related genes (DE-MRGs) in DFU samples relative to controls. LASSO and SVM-RFE algorithms were used to identify critical genes, and functional enrichment analyses were conducted to identify associated pathways. Results were validated in a cohort of DFU samples and controls processed at our institution, and single-cell RNA sequencing data from GSE245703 was used to determine expression of candidate genes in endothelial cells from DFU relative to non-DFU samples. SiRNA knockdown of one candidate gene, LETM2, was performed in human umbilical vein endothelial cells (HUVECs) exposed to H₂O₂ as a model system for oxidative stress. Results LETM2 emerged as key gene significantly associated with DFU from our integrated analysis of the DFU RNA sequencing datasets. Single-cell RNA sequencing data revealed increased expression of LETM2 in endothelial cells from DFU samples compared to controls. Transcriptome sequencing of RNA from HUVECs with LETM2 knockdown under oxidative stress conditions revealed corelated expression with other genes involved in mitochondrial function. HUVECs with LETM2 knockdown furthermore showed impaired mitochondrial fission and mitophagy, as well as decreased cell viability and increased apoptosis in vitro. Conclusions These findings indicate a role for LETM2 in preserving mitochondrial function in HUVECs under oxidative stress and underscore its potential as a therapeutic target for mitigating mitochondrial dysfunction in diabetic complications such as DFU.