Preliminary study of key specific genes involved in tubular ferroptosis in diabetic kidney disease

Objective To explore the key genes of ferroptosis involved in renal tubulointerstitium of diabetic kidney disease （DKD） and its clinical relevance by bioinformatics analysis. Methods DKD and non-DKD datasets of renal tubulointerstitial tissue were obtained to identify differentially expressed genes （DEGs）, and DKD-specific ferroptosis-related genes. Functional enrichment and protein-protein interaction network （PPI） analyses were conducted. After screening key genes, clinical correlation analysis and quantitative real-time PCR （qPCR） were performed for validation. The relationship between key genes and immune microenvironment was explored. Results A total of 37 ferroptosis-associated DEGs in DKD were screened, and they were mainly enriched in metabolic, lipid peroxidation, and inflammatory response signaling pathways. Among the 37 ferroptosis-related genes, 5 genes （PTEN, VEGFA, HSPA5, MAPK8, CD44, ATM） were identified as DKD-specific ferroptosis-associated genes. qPCR showed that the mRNA level of PTEN was significantly up-regulated and that of VEGFA was significantly down-regulated in high glucose-treated human kidney proximal tubular epithelial （HK-2） cells. Nephroseq data showed that the mRNA expression level of VEGFA was positively correlated with glomerular filtration rate （GFR）, and the Person correlation coefficient （r value） was 0.67 （P<0.05）. It was negatively correlated with urinary protein and serum creatinine, with the r value of -0.79 （P<0.05）. The mRNA levels of HSPA5 and PTEN were negatively correlated with GFR in DKD patients, with r values of -0.60 and -0.90, respectively （P<0.05）. The mRNA level of ATM was positively correlated with serum creatinine, with the r value of 0.53 （P<0.05）. The mRNA level of VEGFA was positively correlated with memory T cells, with the r value of 0.69 （P<0.05）. Conclusions VEGFA and PTEN may be specific molecules involved in ferroptosis in DKD, and may participate in the occurrence and development of DKD via regulating lipid metabolism, oxidative stress, and inflammatory response.