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.
Keywords: OGT; O‐glycoproteome; diabetic kidney disease; podocytes; proteome.
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