Metabolic, morphologic and translational alterations during differentiation of the H9c2 cardiomyoblast cell line

Abstract

Heart failure is a condition with increasing incidence, and remains a global pandemic. In vitro studies of molecular mechanisms aid in understanding the processes leading to and augmenting heart failure. The H9c2 cell line is an established model for the research of cardiac metabolism, toxicity studies and heart failure, mainly due to its origin from myocardial tissue. It possesses the ability to differentiate from an embryonic undifferentiated phenotype toward a cardiac muscular phenotype, induced by all-trans-retinoic acid (RA) and low serum concentrations in the culturing media. The alterations following differentiation increases its resemblance with adult cardiomyocytes with regard to morphology and metabolism. This study aims to further increase knowledge about the cell line’s metabolic and morphologic characteristics after RA-treatment. We differentiated H9c2 cells for 5, 10 and 15 days and assessed the cells by respirometry, real-time qPCR and immunostaining. Our results are not conclusive, but still shows major remodeling during RA-induced maturing of the H9c2 cells. During RA-induced differentiation the cells appear larger and elongated, ordering themselves in a parallel fashion. Results from qPCR shows an early increase in expression of structural genes, while metabolic genes are upregulated later in the differentiation. Results from respirometry shows increased oxidative phosphorylation and increased spare capacity due to increased mitochondrial content.