Endothelial Ferroptosis as a Causal Driver of Diabetic Nephropathy: Insights from Multiomics and Mendelian Randomization

Background: Diabetic nephropathy (DN) has emerged as a predominant contributor to end-stage renal disease globally. Recent studies have highlighted ferroptosis as a potentially critical factor in DN pathogenesis. Despite growing evidence linking ferroptosis to DN progression, the causal mechanisms remain poorly understood. Moreover, the precise involvement of ferroptosis-related genes in glomerular cell dysfunction during DN development warrants further investigation. Methods: We first retrieved 933 ferroptosis-related genes from the FerrDb database. Using cis-expression quantitative trait loci data from the eQTLGen consortium, we performed Mendelian randomization to assess the causal effects of these genes on type 2 diabetes. Genes demonstrating significant associations were further evaluated for their causal roles in DN. To ensure robustness, we validated key candidate genes using independent datasets from multiple sources. Finally, we integrated single-cell RNA sequencing (scRNA-seq) and single-cell ATAC sequencing (scATAC-seq) data from DN kidney tissues to explore cell-type-specific expression patterns, differential expression across glomerular cell subtypes, and potential transcriptional regulators of these genes. Results: CDKN1A was identified as a potential risk factor for DN, whereas CEBPG and EPAS1 exhibited protective effects. Multi-omics integration demonstrated pronounced activation of ferroptosis signaling in endothelial cells, which was closely linked to inflammatory cell infiltration. CDKN1A, CEBPG, and EPAS1 were predominantly enriched in endothelial cells and displayed elevated chromatin accessibility. FOS, FOSL2, and BHLHE40 may serve as upstream regulators of CDKN1A, potentially governing its expression and downstream pathological effects. Conclusion: CDKN1A, CEBPG and EPAS1 were identified as key regulators of endothelial ferroptosis in DN, highlighting their potential as molecular targets for intervention.