{'fraction_non_alphanumeric': 0.03768318213538032, 'fraction_numerical': 0.013258897418004187, 'mean_word_length': 5.669767441860465, 'pattern_counts': {'":': 0, '<': 4, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Adenovirus-Mediated Overexpression of O-GlcNAcase Improves Contractile Function in the Diabetic Heart

To examine whether excessive protein O-GlcNAcylation plays a role in the dysfunction of the diabetic heart, we delivered adenovirus expressing O-GlcNAcase (Adv-GCA) into the myocardium of STZ-induced diabetic mice. Our results indicated that excessive cellular O-GlcNAcylation exists in the diabetic heart, and that in vivo GCA overexpression reduces overall cellular O-GlcNAcylation. Myocytes isolated from diabetic hearts receiving Adv-GCA exhibited improved calcium transients with a significantly shortened Tdecay (P<0.01) and increased sarcoplasmic reticulum Ca2+ load (P<0.01). These myocytes also demonstrated improved contractility including a significant increase in +dL/dt and −dL/dt and greater fractional shortening as measured by edge detection (P<0.01). In isolated perfused hearts, developed pressure and −dP/dt were significantly improved in diabetic hearts receiving Adv-GCA (P<0.05). These hearts also exhibited a 40% increase in SERCA2a expression. Phospholamban protein expression was reduced 50%, but the phosphorylated form was increased 2-fold in the diabetic hearts receiving Adv-GCA. We conclude that excess O-GlcNAcylation in the diabetic heart contributes to cardiac dysfunction, and reducing this excess cellular O-GlcNAcylation has beneficial effects on calcium handling and diabetic cardiac function.