O-GlcNAcylation Mediates Glucose-Induced Alterations in Endothelial Cell Phenotype in Human Diabetes Mellitus

• Published in: Journal of the American Heart Association 2020-06, Vol.9 (12), p.e014046
• Main Authors: Masaki, Nobuyuki, Feng, Bihua, Bretón-Romero, Rosa, Inagaki, Elica, Weisbrod, Robert M, Fetterman, Jessica L, Hamburg, Naomi M
• Format: Article
• Language: English
• Subjects: Adult; beta-N-Acetylhexosaminidases - metabolism; Case-Control Studies; Cells, Cultured; diabetes mellitus; Diabetes Mellitus, Type 2 - diagnosis; Diabetes Mellitus, Type 2 - metabolism; Endothelial Cells - drug effects; Endothelial Cells - metabolism; endothelial nitric oxide synthase; Female; Forearm - blood supply; Glucose - pharmacology; Glucose - toxicity; Glycosylation; Humans; Insulin - pharmacology; insulin resistance; Male; Middle Aged; Nitric Oxide Synthase Type III - metabolism; Original Research; O‐GlcNAc; Phenotype; Phosphorylation; Protein Processing, Post-Translational - drug effects
• ISSN: 2047-9980; 2047-9980
• DOI: 10.1161/jaha.119.014046

Background Posttranslational protein modification with O-linked -acetylglucosamine (O-GlcNAc) is linked to high glucose levels in type 2 diabetes mellitus (T2DM) and may alter cellular function. We sought to elucidate the involvement of O-GlcNAc modification in endothelial dysfunction in patients with T2DM. Methods and Results Freshly isolated endothelial cells obtained by J-wire biopsy from a forearm vein of patients with T2DM (n=18) was compared with controls (n=10). Endothelial O-GlcNAc levels were 1.8-ford higher in T2DM patients than in nondiabetic controls ( =0.003). Higher endothelial O-GlcNAc levels correlated with serum fasting blood glucose level ( =0.433, =0.024) and hemoglobin A ( =0.418, =0.042). In endothelial cells from patients with T2DM, normal glucose conditions (24 hours at 5 mmol/L) lowered O-GlcNAc levels and restored insulin-mediated activation of endothelial nitric oxide synthase, whereas high glucose conditions (30 mmol/L) maintained both O-GlcNAc levels and impaired insulin action. Treatment of endothelial cells with Thiamet G, an O-GlcNAcase inhibitor, increased O-GlcNAc levels and blunted the improvement of insulin-mediated endothelial nitric oxide synthase phosphorylation by glucose normalization. Conclusions Taken together, our findings indicate a role for O-GlcNAc modification in the dynamic, glucose-induced impairment of endothelial nitric oxide synthase activation in endothelial cells from patients with T2DM. O-GlcNAc protein modification may be a treatment target for vascular dysfunction in T2DM.