Loss of NRF2 During Aging Contributes to Myocardial Functional Decline

Aging is a significant risk factor for cardiovascular diseases. The prevalence of heart failure increases with age, making it a leading cause of morbidity and mortality. We investigated age-associated changes in expression of Nuclear Factor (Erythroid-derived 2)-Like 2 (NFE2L2 or NRF2) in the myocardium of humans, rhesus monkeys, Fischer rats, and C57BL/6 mice. NRF2 is a transcription factor that orchestrates the expression of genes involved in antioxidant and detoxification responses. Analyses of RNA-seq data from the Genotype-Tissue Expression (GTEx) project, which contains left ventricular samples from 294 male donors, revealed a trend of age-associated declines in NRF2 transcripts and several of its downstream genes (SOD1, SOD2, CAT, GCLM, and AKR1B). Age-dependent decreases in NRF2 protein expression were observed in the myocardium of Rhesus monkeys and Fischer rats. To determine whether NRF2 loss contributes to myocardial aging, we evaluated cardiac function of NRF2 knockout mice (KO) at 19 and 24 months of age. At 19 months, the NRF2 KO mice exhibited diastolic dysfunction, characterized by an increased end-diastolic volume (EDV) and end-systolic volume (ESV), accompanied by a reduced ejection fraction (EF) and fractional shortening (FS), indicative of early onset of heart failure. The NRF2 KO mice displayed premature aging phenotypes and had reduced lifespans. Our findings support the trend of NRF2 signaling decline with age, and that loss of NRF2 accelerates the maladaptive cardiac remodeling and functional deterioration associated with aging.