Malondialdehyde and 4-hydroxynonenal adducts are not formed on cardiac ryanodine receptor (RyR2) and sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA2) in diabetes.
Recently, we reported an elevated level of glucose-generated carbonyl adducts on cardiac ryanodine receptor (RyR2) and sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA2) in hearts of streptozotocin(STZ)-induced diabetic rats. We also showed these adduct impaired RyR2 and SERCA2 activities, and altered evoked Ca(2+) transients. What is less clear is if lipid-derived malondialdehyde (MDA) and 4-hydroxy-2-nonenal (4-HNE) also chemically react with and impair RyR2 and SERCA2 activities in diabetes? This study used western blot assays with adduct-specific antibodies and confocal microscopy to assess levels of MDA, 4-HNE, N (ε)-carboxy(methyl)lysine (CML), pentosidine, and pyrraline adducts on RyR2 and SERCA2 and evoked intracellular transient Ca(2+) kinetics in myocytes from control, diabetic, and treated-diabetic rats. MDA and 4-HNE adducts were not detected on RyR2 and SERCA2 from either control or 8 weeks diabetic rats with altered evoked Ca(2+) transients. However, CML, pentosidine, and pyrraline adducts were elevated three- to five-fold (p < 0.05). Treating diabetic rats with pyridoxamine (a scavenger of reactive carbonyl species, RCS) or aminoguanidine (a mixed reactive oxygen species-RCS scavenger) reduced CML, pentosidine, and pyrraline adducts on RyR2 and SERCA2 and blunted SR Ca(2+) cycling changes. Treating diabetic rats with the superoxide dismutase mimetic tempol had no impact on MDA and 4-HNE adducts on RyR2 and SERCA2, and on SR Ca(2+) cycling. From these data we conclude that lipid-derived MDA and 4-HNE adducts are not formed on RyR2 and SERCA2 in this model of diabetes, and are therefore unlikely to be directly contributing to the SR Ca(2+) dysregulation.
Department of Pharmacology and Experimental Neuroscience, 985800 Nebraska Medical Center, Durham Research Center, Omaha, NE 68198-5800, USA.
Caronda J
CJ
Moore
Chun Hong
CH
Shao
Ryoji
R
Nagai
Shelby
S
Kutty
Jaipaul
J
Singh
Keshore R
KR
Bidasee
D000447:Aldehydes / Q000737:chemistry / Q000378:metabolism*; D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives / Q000737:chemistry / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D003497:Cyclic N-Oxides / Q000494:pharmacology; D003921:Diabetes Mellitus, Experimental / Q000188:drug therapy / Q000378:metabolism* / Q000503:physiopathology; D058065:Diabetic Cardiomyopathies / Q000378:metabolism; D004452:Echocardiography / Q000379:methods; D006146:Guanidines / Q000494:pharmacology; D008239:Lysine / Q000031:analogs & derivatives / Q000737:chemistry / Q000378:metabolism; D008297:Male; D008315:Malondialdehyde / Q000737:chemistry / Q000378:metabolism*; D032383:Myocytes, Cardiac / Q000187:drug effects / Q000378:metabolism*; D009646:Norleucine / Q000031:analogs & derivatives / Q000737:chemistry / Q000378:metabolism; D050050:Protein Carbonylation; D011733:Pyridoxamine / Q000494:pharmacology; D011758:Pyrroles / Q000737:chemistry / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D019837:Ryanodine Receptor Calcium Release Channel / Q000737:chemistry / Q000378:metabolism*; D012519:Sarcoplasmic Reticulum / Q000378:metabolism; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases / Q000737:chemistry / Q000378:metabolism*; D013113:Spin Labels
D000447:Aldehydes; C506948:Atp2a2 protein, rat; D003497:Cyclic N-Oxides; D006146:Guanidines; D011758:Pyrroles; D019837:Ryanodine Receptor Calcium Release Channel; D013113:Spin Labels; D008315:Malondialdehyde; D011733:Pyridoxamine; C048496:N(6)-carboxymethyllysine; C059571:2-formyl-5-(hydroxymethyl)pyrrole-1-norleucine; D009646:Norleucine; D001120:Arginine; C062187:pentosidine; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases; C027576:4-hydroxy-2-nonenal; D008239:Lysine; C004479:pimagedine; D002118:Calcium; C001803:tempol