Dihydroorotate Dehydrogenase as a Modulator of Ferroptosis in Myocardial Ischemia-reperfusion Injury

Ferroptosis is increasingly acknowledged as a pivotal contributor to myocardial cell injury in ischemia-reperfusion (I/R). As a central enzyme in the pyrimidine synthesis pathway, dihydroorotate dehydrogenase (DHODH) is implicated in maintaining redox homeostasis and is thought to act as a protective agent against ferroptosis. Despite this association, the specific contributions of DHODH to myocardial ischemia-reperfusion injury (MIRI) and its cardioprotective potential remain inadequately elucidated.

This study aimed to delineate the role of DHODH in MIRI and assess its capacity to modulate ferroptosis in cardiomyocytes.

We utilized AC16 cardiomyocytes to establish an in vitro MIRI model to investigate the role of DHODH in ferroptosis. We quantitatively analyzed DHODH expression during I/R injury, along with its distribution in cytoplasmic and mitochondrial compartments. Cells pretreated with dihydroorotate (DHO) and orotate (OA)-the substrate and product of DHODH, respectively-provided a basis for assessing their susceptibility to ferroptosis. By employing siRNA to suppress DHODH expression, we delved into the underlying mechanisms of DHODH's protective role against I/Rinduced ferroptosis, focusing on oxidative stress and mitochondrial dysfunction.

Our findings reveal a significant induction of DHODH expression during ferroptosis in the AC16 I/R model. DHO pretreatment conferred resistance to ferroptosis, while OA pretreatment rendered cells more susceptible. Notably, DHODH silencing aggravated ferroptosis indicators, mainly through increased oxidative stress and mitochondrial dysfunction.

DHODH emerges as a key modulator of ferroptosis in the context of MIRI, offering protection predominantly through its antioxidative functions and maintenance of mitochondrial integrity.