Sex-Specific Mitochondrial Metabolic and Transcriptomic Signatures in Type 2 Diabetic Kidney Disease

Background: Type 2 diabetic kidney disease (T2DKD) is a leading cause of end-stage renal disease (ESRD), characterized by metabolic dysregulation and progressive mitochondrial pathology. Emerging evidence highlights sex differences in the pathophysiology of T2DKD, yet the underlying mechanisms remain poorly understood. Men exhibit accelerated development of kidney damage with high oxidative stress and fast development of fibrosis and podocyte dysfunction; however, women have a higher risk of ESRD development and poorer cardiovascular outcomes. We hypothesized that mitochondria-specific metabolic mechanisms drive sex-specific disparities in T2DKD progression. Methods: Targeted metabolomic analysis of mitochondria-related metabolic pathways using the kidney cortex and urine and transcriptomic analysis of the kidney cortex was performed. Male and female type 2 diabetic nephropathy rat model (T2DN) at 14-15 weeks (early stage of T2DKD), 48-52 weeks (late stage of T2DKD), and age-matched Wistar controls were used to analyze metabolic and transcriptomic alterations. A semi-automatic approach was used for the analysis of pathway-specific alterations. N = 6 for each group. Metabolic profiles were generated using UHPLC-HRMS; metabolites were identified in El-MAVEN using exact mass and retention time with an in-house library. MetaboAnalyst 6.0 was used for statistical analysis (cutoff fold change 0.5, p < 0.05). For transcriptomic analysis, genes were considered differentially expressed with adjusted p < 0.05 and |EFC| > 1.5. Enrichment analysis of gene ontologies (GO) and network connectivity was performed using the Search Tool for the Retrieval of Interacting Genes (STRING) database. Results: Our data indicate that amino acid (AA) profiles were differentially abundant in the kidney cortex between males and females. At the early stage of T2DKD, we observed elevated lysine, arginine, and ornithine (p < 0.05), in the cortex of females. Differences in renal AA distribution were also evident at the late stage of T2DKD progression with elevated arginine and homocitrulline in females. Of note, we observed differences in purinergic salvage cycle metabolites between sexes (p < 0.05). Allantoin (uric acid metabolic byproduct) was lower in the female cortex at both stages of T2DKD development. In the urine, purinergic metabolites also presented differently, as indicated by reduced dAMP, 5′-Methylthioadenosine (MTA), and thymidine and increased guanine, cytosine, and dUMP at the early stage of T2DKD in females. Some of the purinergic system metabolites (MTA, alpha-ketoglutarate) persisted at the late stage of T2DKD. These findings indicate that adaptations in mitochondrial function and oxidative stress homeostasis mechanisms are distinct between sexes in T2DKD. Our transcriptomic analysis confirmed this, showing increased expression of genes responsible for mitochondrial lipid metabolism and fatty acid oxidation in females (enrichment p < 0.0001). Importantly, we observed higher expression of Cytochrome P450 regulating genes in females (enrichment p < 0.0001), which is a potential contributor to oxidative stress. Conclusion: Our data suggest that sex differences in mitochondrial metabolism in diabetes include AA metabolism, particularly AAs relevant for nitric oxide production and polyamine synthesis, as well as purinergic signaling, and oxidative stress. Targeting these processes in the kidney may be beneficial for sex-specific renal protection. This research was supported by NIH Grants R01 DK126720, R01 DK129227, R01 HL148114. This abstract was presented at the American Physiology Summit 2025 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.