OPLAH prevents accumulation of cardiotoxic 5-oxoproline after ischemic injury and improves cardiac function

In response to heart failure (HF), the heart reacts by repressing adult genes and expressing fetal genes, thereby returning to a more fetal-like gene profile. To identify genes involved in this process, we carried out transcriptional analysis on murine hearts at different stages of development and adult mice with HF. Our screen identified 5-oxoprolinase (OPLAH), a member of the ?-Glutamyl cycle, that functions by scavenging 5-oxoproline. OPLAH depletion occurred as a result of cardiac injury, leading to elevated 5-oxoproline and oxidative stress, whereas OPLAH overexpression improved cardiac function after ischemic injury. In HF patients we observed elevated plasma 5-oxoproline levels, which were associated with a worse clinical outcome. Understanding and modulating fetal-like genes in the failing heart may lead to potential novel diagnostic, prognostic and therapeutic options in HF.