OBJECTIVEOverexpression of SERCA2a could improve cardiac function in human and experimental heart failure (HF) models. We observed the proteomics changes post SERCA2a overexpression in a pacing induced HF model in dogs.

METHODSBeagles were divided into four groups: control group, HF group (230 beats/min for 4 weeks), HF + EGFP group (myocardial injection of 1 x 10(12) v.g recombinant adeno-associated virus carrying enhanced green fluorescent protein gene, rAAV2/1-EGFP) and HF + SERCA2a group (myocardial injection of 1 x 10(12) v.g recombinant adeno-associated virus carrying SERCA2a gene, rAAV2/1-SERCA2a). Thirty days after gene transduction, left ventricular systolic and diastolic functions were measured by echocardiography and invasive hemodynamics in all animals. By use of 2-dimensional gel electrophoresis (2-DE), -500 distinct protein spots were detected in myocardium of all animals. Protein spots observed to be altered between failing and SERCA2a overexpressed hearts were subjected to tryptic peptide mass fingerprinting for identification by MALDI-TOF mass spectrometry in combination with LC/MS/MS analysis.

RESULTSAt 30 day after gene transfer, HF signs were significantly reduced, cardiac function [LVSP: (214.72 +/- 31.74) mm Hg (1 mm Hg = 0.133 kPa) vs. (139.32 +/- 36.79) mm Hg, +dp/dt(max): (6779.43 +/- 217.58) mm Hg/s vs. (2746.85 +/- 931.23) mm Hg/s and -dp/dt(max): (-4341.42 +/- 322.02) mm Hg/s vs. (-2531.14 +/- 616.15) mm Hg/s, LVEDP: (21.86 +/- 6.95) mm Hg vs. (59.78 +/- 6.92) mm Hg] significantly improved in HF + SERCA2a dogs than those in HF + EGFP group(all P < 0.05) and parameters were comparable between HF + SERCA2a and control groups. We identified alterations in the expression level of more than 10 proteins in myocardium. These protein changes were observed mainly in two subcellular compartments: the cardiac contractile apparatus and metabolism/energetics.

CONCLUSIONThese results showed that overexpression of SERCA2a could improve cardiac function accompanied with numerous alterations in protein expressions involved in calcium handling, myofibrils, and energy production in this dog model of chronic heart failure.