Conditional Knockout of Prolyl Hydroxylase Domain Protein 2 Attenuates High Fat-Diet-Induced Cardiac Dysfunction in Mice

Oxygen sensor prolyl hydroxylases (PHDs) play important roles in the regulation of HIF-α and cell metabolisms. This study was designed to investigate the direct role of PHD2 in high fat-diet (HFD)-induced cardiac dysfunction. In HFD fed mice, PHD2 expression was increased without significant changes in PHD1 and PHD3 levels in the heart. This was accompanied by a significant upregulation of myeloid differentiation factor 88 (MYD88) and NF-κB. To explore the role of PHD2 in HFD-induced cardiac dysfunction, PHD2 conditional knockout mice were fed a HFD for 16 weeks. Intriguingly, knockout of PHD2 significantly reduced MYD88 and NF-κb expression in HFD mouse hearts. Moreover, knockout of PHD2 inhibited TNFα and ICAM-1 expression, and reduced cell apoptosis and macrophage infiltration in HFD mice. This was accompanied by a significant improvement of cardiac function. Most importantly, conditional knockout of PHD2 at late stage in HFD mice significantly improved glucose tolerance and reversed cardiac dysfunction. Our studies demonstrate that PHD2 activity is a critical contributor to the HFD-induced cardiac dysfunction. Inhibition of PHD2 attenuates HFD-induced cardiac dysfunction by a mechanism involving suppression of MYD88/NF-κb pathway and inflammation.