Multiomics analysis of O‐GlcNAcylation in podocytes of diabetic kidney disease

Abstract Aim To investigate the role of O‐GlcNAc transferase (OGT)‐mediated protein O‐GlcNAcylation in podocyte injury during the progression of diabetic kidney disease (DKD). Materials and Methods Proteomic and O‐glycoproteomic analyses were conducted on high glucose (HG)‐stimulated podocytes with OGT knockdown. Differentially expressed proteins and O‐GlcNAcylated peptides/proteins were identified, and functional enrichment (GO, KEGG, COG/KOG) and motif analysis (motif‐x) were performed using bioinformatics analysis. Co‐immunoprecipitation (Co‐IP) was used to validate O‐GlcNAcylation of candidate proteins. Results OGT knockdown in HG‐treated podocytes resulted in 128 upregulated and 45 downregulated proteins. Glycoproteomics revealed 32 glycopeptides/21 glycoproteins upregulated and 37 glycopeptides/22 glycoproteins downregulated. The focus was on down‐regulated glycosylated proteins without changes in their protein levels. These proteins are predominantly enriched in translation factor activity, RNA binding, and ECM‐receptor interactions pathways. Among these proteins, Caprin1, Lrp1, and Sil1 were modified by O‐GlcNAcylation. Conclusion OGT‐driven O‐GlcNAcylation exacerbates podocyte injury in DKD by post‐translationally modifying key regulators of translational machinery and ECM signalling. Precision targeting of O‐GlcNAc dynamics represents a promising therapeutic strategy to attenuate DKD.