S-nitrosoglutathione reductase (GSNOR), a regulator of protein S-nitrosylation (SNO), has been proposed as a longevity protein. GSNOR signaling has been implicated in both the alleviation and exacerbation of aging. In the context of ischemia-reperfusion injury, we previously showed a sex-dependent response to GSNOR inhibition; cardiac damage was alleviated in males and exacerbated in females. Considering sex differences in the incidence of cardiovascular disease with age, we investigated the effect of GSNOR deletion ( -/- ) on age-related changes in cardiac function. We performed longitudinal 2D-echocardiography measurements in M-Mode on male and female, wildtype (WT) and GSNOR -/- mice at young (3-4 months), middle (13-15 months) and old age (18-20 months). Left ventricular wall thickness and ejection fraction decreased with age in WT mice but was maintained in GSNOR -/- . Western blot and GSNOR activity assays showed GSNOR activity and expression decreased with age in WT females. Isolated cardiomyocyte force-coupling analysis showed increasing age was inversely correlated with sarcomere shortening and Ca 2+ release kinetics in WT males, but not GSNOR -/- . WT females showed slower Ca 2+ re-uptake after contraction and time to peak sarcomere shortening, but all other parameters were maintained. GSNOR -/- females exhibited slower Ca 2+ re-uptake and decreased sarcomere shortening. Proteomic analysis of SNO from females showed increased modification of Pyruvate Dehydrogenase, E1 Beta and Dihydrolipoamide dehydrogenase in young WT females relative to middle-age mice. Together our data suggest that GSNOR deletion is beneficial in males by maintaining cardiac function; while the absence of GSNOR in females removes an age-essential SNO-imbalance, which may exacerbate age-related pathology.
Ebenebe et al. (Wed,) studied this question.