Ramirez-Correa, G.A.Ma, J.Slawson, C.Zeidan, Q.Lugo-Fagundo, N.S.Xu, M.Shen, X.Gao, W.D.Caceres, V.Chakir, K.DeVine, L.Cole, R.N.Marchionni, L.Paolocci, N.Hart, G.W.Murphy, A.M.2025-07-162025-07-162015Diabetes, 2015; 64(10):3573-35870012-17970012-1797https://hdl.handle.net/2440/145981Contractile dysfunction and increased deposition of O-linked β-N-acetyl-d-glucosamine (O-GlcNAc) in cardiac proteins are a hallmark of the diabetic heart. However, whether and how this posttranslational alteration contributes to lower cardiac function remains unclear. Using a refined β-elimination/Michael addition with tandem mass tags (TMT)-labeling proteomic technique, we show that CpOGA, a bacterial analog of O-GlcNAcase (OGA) that cleaves O-GlcNAc in vivo, removes site-specific O-GlcNAcylation from myofilaments, restoring Ca(2+) sensitivity in streptozotocin (STZ) diabetic cardiac muscles. We report that in control rat hearts, O-GlcNAc and O-GlcNAc transferase (OGT) are mainly localized at the Z-line, whereas OGA is at the A-band. Conversely, in diabetic hearts O-GlcNAc levels are increased and OGT and OGA delocalized. Consistent changes were found in human diabetic hearts. STZ diabetic hearts display increased physical interactions of OGA with α-actin, tropomyosin, and myosin light chain 1, along with reduced OGT and increased OGA activities. Our study is the first to reveal that specific removal of O-GlcNAcylation restores myofilament response to Ca(2+) in diabetic hearts and that altered O-GlcNAcylation is due to the subcellular redistribution of OGT and OGA rather than to changes in their overall activities. Thus, preventing sarcomeric OGT and OGA displacement represents a new possible strategy for treating diabetic cardiomyopathy.en© 2015 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered.Acetylglucosaminebeta-N-AcetylhexosaminidasesCalciumDiabetes Mellitus, ExperimentalDiabetic CardiomyopathiesGene Expression Regulation, EnzymologicMyocardiumMyofibrilsRats, Sprague-DawleySarcomeresMyofibrilsSarcomeresMyocardiumAnimalsHumansRatsRats, Sprague-DawleyDiabetes Mellitus, ExperimentalCalciumAcetylglucosamineGene Expression Regulation, EnzymologicMalebeta-N-AcetylhexosaminidasesDiabetic CardiomyopathiesJournal article10.2337/db14-11072024-07-03690456Bai, X. [0000-0001-7994-9152]