Proteomic analysis reveals beneficial effects of ellagic acid on renal cells via mitigating oxalate-induced oxidative stress and mitochondrial dysfunction

Abstract

Oxidative stress caused by oxalate is one of the key pathogenic factors causing renal tubular injury and kidney stone formation. Recent studies have reported that ellagic acid (a natural polyphenol abundantly present in various fruits, nuts and medicinal plants with known antioxidant properties) has potential renoprotective effects, but with unclear molecular mechanisms. To investigate the cellular impact of ellagic acid, we applied quantitative proteomics, bioinformatics (protein interaction network mapping, gene ontology enrichment, and K-means clustering), and functional assays (Western blotting, OxyBlot assay, MitoTracker staining, and protein aggregation assay) to identify key pathways and functional clusters mediated by ellagic acid. Proteomic profiling identified 8 downregulated and 13 upregulated proteins induced by ellagic acid. Bioinformatic analyses identified some important central regulatory nodes within interaction networks, including ATIC, HSPH1 and TPI1 among downregulated proteins, and hnRNPK, EIF6 and HSPA8 among upregulated ones. Functional annotation indicated that stress response and mitochondrial function were involved. Functional validation revealed that ellagic acid prevented oxalate-induced protein oxidation and preserved mitochondrial integrity and membrane potential, indicating its strong antioxidant effects. However, ellagic acid did not affect protein aggregation. In conclusion, ellagic acid exerted multifaceted cytoprotective effects in renal tubular cells by modulating the expression of several proteins and their interaction networks, mitigating oxidative protein damage, and preserving mitochondrial function. These findings provide mechanistic insights into the renoprotective actions of ellagic acid and support its promise as a therapeutic agent against renal injury caused by oxalate.