Shifts in contractile regulatory protein subunits troponin T and troponin I in cardiac hypertrophy.
To examine the molecular basis of hypertrophied heart failure, we investigated the changes in cardiac contractile regulatory proteins. The guinea pigs were subjected to chronic pressure overload with aortic banding to induce ventricular hypertrophy, and in-situ pressure-volume relations were recorded together with biochemical characterizations to ascertain the contractile modifications. Immunoblots of left and right ventricular samples revealed four distinct troponin T isoforms, which underwent alterations during hypertrophy. The higher molecular weight bands TnT1 and TnT2 shifted towards the lower molecular weight isoforms TnT3 and TnT4. For TnI, a single prominent band was detected, whose intensity also increased with pump failure. The findings provide the first direct evidence of TnT and TnI shifts in an experimentally induced hypertrophied heart failure and has novel mechanistic implications for the future studies.
Department of Medicine, Albert Einstein College of Medicine, Bronx, New York 10461.
J
J
Gulati
A B
AB
Akella
S D
SD
Nikolic
V
V
Starc
F
F
Siri
D000818:Animals; D015415:Biomarkers / Q000032:analysis; D015153:Blotting, Western; D006332:Cardiomegaly / Q000378:metabolism / Q000503:physiopathology*; D003971:Diastole; D004591:Electrophoresis, Polyacrylamide Gel; D006168:Guinea Pigs; D006321:Heart / Q000502:physiology / Q000503:physiopathology*; D046911:Macromolecular Substances; D008297:Male; D009200:Myocardial Contraction; D009206:Myocardium / Q000378:metabolism*; D012016:Reference Values; D013599:Systole; D014336:Troponin / Q000032:analysis / Q000096:biosynthesis* / Q000302:isolation & purification; D019210:Troponin I; D020107:Troponin T; D016277:Ventricular Function, Left
D015415:Biomarkers; D046911:Macromolecular Substances; D014336:Troponin; D019210:Troponin I; D020107:Troponin T