N-terminal truncated peroxisome proliferator-activated receptor- coactivator-1 alleviates phenylephrine-induced mitochondrial dysfunction and decreases lipid droplet accumulation in neonatal rat cardiomyocytes

摘要

N-terminal truncated peroxisome proliferator-activated receptor- coactivator-1 (NT-PGC-1) is an alternative splice variant of PGC-1. NT-PGC-1 exhibits stronger anti-obesity effects in adipose tissue than PGC-1; however, NT-PGC-1 has not yet been investigated in neonatal rat cardiomyocytes (NRCMs). The present study aimed to investigate the role of NT-PGC-1 in mitochondrial fatty acid metabolism and its possible regulatory mechanism in NRCMs. NRCMs were exposed to phenylephrine (PE) or angiotensin II (Ang II) to induce cardiac hypertrophy. Following this, NRCMs were infected with adenovirus expressing NT-PGC-1, and adenosine 5-triphsophate (ATP) levels, reactive oxygen species (ROS) generation and mitochondrial membrane potential were subsequently detected. In addition, western blotting, lipid droplet staining and oxygen consumption assays were performed to examine the function of NT-PGC-1 in fatty acid metabolism. NT-PGC-1 was demonstrated to be primarily expressed in the cytoplasm, which differed from full-length PGC-1, which was predominantly expressed in the nucleus. NT-PGC-1 overexpression alleviated mitochondrial function impairment, including ATP generation, ROS production and mitochondrial membrane potential integrity. Furthermore, NT-PGC-1 overexpression alleviated the PE-induced suppression of fatty acid metabolism-associated protein expression, increased extracellular oxygen consumption and decreased lipid droplet accumulation in NRCMs. Taken together, the present study demonstrated that NT-PGC-1 alleviated PE-induced mitochondrial impairment and decreased lipid droplet accumulation in NRCMs, indicating that NT-PGC-1 may have ameliorated mitochondrial energy defects in NRCMs, and may be considered as a potential target for the treatment of heart failure.