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Carbonylation Induces Ryanodine Receptor Dysregulation During Diabetes
Author(s) -
Bidasee Keshore R,
Shao Chun-Hong,
Tian Chengju,
Moore Caronda J,
Singh Jaipaul,
Rozanski George
Publication year - 2012
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.26.1_supplement.1057.2
Subject(s) - ryanodine receptor , ryanodine receptor 2 , medicine , chemistry , endocrinology , protein carbonylation , carbonylation , diabetes mellitus , hek 293 cells , trpc , myocyte , receptor , oxidative stress , transient receptor potential channel , biochemistry , carbon monoxide , catalysis , oxidative damage
We and others earlier found that cardiac ryanodine receptor Ca 2+ release channels (RyR2) becomes dysregulated during diabetes and suggested this defect to be a contributing cause for increased incidence of heart failure (HF) and fatal ventricular arrhythmias in individuals with diabetes mellitus. To date, mechanisms responsible for RyR2 dysregulation during diabetes remain poorly understood. This study assesses whether carbonylation (modification by reactive carbonyl species, RCS) is an underlying cause. After 8 weeks of diabetes, spontaneous Ca 2+ released was enhanced and evoked Ca 2+ release became dyssynchronous (non‐uniform) in ventricular myocytes from diabetic rats. RyR2 protein level remained unchanged but its capacity to bind the Ca 2+ ‐dependent ligand [ 3 H]ryanodine was significantly reduced. Western blots and mass spectroscopic analyses revealed carbonyl adducts on select basic residues of RyR2. Altering charge and increasing bulk on affected residues to mimic carbonylation resulted in channels with low to exaggerated cytoplasmic Ca 2+ responses, akin to that seen during diabetes. Expressing carbonylation‐mimicking mutants in RyR2‐null HEK‐ 293T cells triggered abnormal intracellular Ca 2+ cycling. Exposing healthy rat ventricular myocytes to the reactive carbonyl species methylglyoxal (MGO) induced aberrant SR Ca 2+ release, similar to that seen in diabetic myocytes. MGO also altered the binding of [ 3 H]ryanodine and the open probability of RyR2. Treating diabetic rats with scavengers of reactive carbonyl species reduced carbonylation of RyR2 and aberrant SR Ca 2+ release. From these new data we conclude that carbonylation is a specific mechanism that contributes to RyR2 dysregulation during diabetes. Funded in part by NIH