Transient elevation in cellular glucose uptake exacerbates pressure overload-induced cardiac hypertrophy and...

Clinically prior hyperglycemia may lead to long-lasting adverse cardiovascular effects, a process referred to as 'glycemic memory.' Epigenetic modifications, specifically DNA methylation changes, may play a key role in this phenomenon. This study investigated if prior high glucose delivery to cardiomyocytes, led to worsened cardiovascular effects upon pressure overload and to ascertain the gene expression and corresponding DNA methylation signatures linked to glycemic memory. Using inducible and cardiomyocyte-specific glucose transporter 4 (GLUT4) overexpressing mice. We induced glucose delivery for 2 weeks, then returned to basal uptake for 2 weeks, followed by sham or transverse aortic constriction (TAC) surgery as a secondary stress. Mice were followed for an additional 8 weeks and assessed for contractile function, cellular remodeling, and molecular changes. TAC led to an exacerbated hypertrophic response and cardiac dysfunction in the transgenic mice. Subsequent analysis identified molecular changes akin to heart failure, worsened cardiac fibrosis, and oxidative stress. Using bulk RNA-sequencing and reduced representation bisulfite sequencing, we discovered differential gene expression and DNA methylation signatures that persisted even after cellular glucose levels reverted to normal. Significant changes across both expression and methylation-identified enriched pathways related to adverse cardiac events, supporting a glycemic memory response. Glycemic memory led to cardiac structural and functional exacerbation, mimicking heart failure, when subjected to a secondary stress. Our data identified transcriptome, and preliminary DNA methylome changes which may potentially be molecular signatures of future therapeutic targets associated with this heart failure susceptibility resulting from enhanced glucose delivery.