Prolyl-hydroxylase inhibition induces SDF-1 associated with increased CXCR4+/CD11b+ subpopulations and cardiac repair.

Unlabelled: SDF-1/CXCR4 activation facilitates myocardial repair. Therefore, we aimed to activate the HIF-1α target genes SDF-1 and CXCR4 by dimethyloxalylglycine (DMOG)-induced prolyl-hydroxylase (PH) inhibition to augment CXCR4+ cell recruitment and myocardial repair. SDF-1 and CXCR4 expression was analyzed under normoxia and ischemia ± DMOG utilizing SDF-1-EGFP and CXCR4-EGFP reporter mice. In bone marrow and heart, CXCR4-EGFP was predominantly expressed in CD45+/CD11b+ leukocytes which significantly increased after myocardial ischemia. PH inhibition with 500 μM DMOG induced upregulation of SDF-1 mRNA in human microvascular endothelial cells (HMEC-1) and aortic vascular smooth muscle cells (HAVSMC). CXCR4 was highly elevated in HMEC-1 but almost no detectable in HAVSMC. In vivo, systemic administration of the PH inhibitor DMOG without pretreatment upregulated nuclear HIF-1α and SDF-1 in the ischemic mouse heart associated with increased recruitment of CD45+/CXCR4-EGFP+/CD11b+ cell subsets. Enhanced PH inhibition significantly upregulated reparative M2 like CXCR4-EGFP+ CD11b+/CD206+ cells compared to inflammatory M2-like CXCR4-EGFP+ CD11b+/CD86+ cells associated with reduced apoptotic cell death, increased neovascularization, reduced scar size, and an improved heart function after MI. In summary, our data suggest increased PH inhibition as a promising tool for a customized upregulation of SDF-1 and CXCR4 expression to attract CXCR4+/CD11b+ cells to the ischemic heart associated with increased cardiac repair.

Key Messages: DMOG-induced prolyl-hydroxylase inhibition upregulates SDF-1 and CXCR4 in human endothelial cells. Systemic application of DMOG upregulates nuclear HIF-1α and SDF-1 in vivo. Enhanced prolyl-hydroxylase inhibition increases mainly CXCR4+/CD11b+ cells. DMOG increased reparative M2-like CD11b+/CD206+ cells compared to M1-like cells after MI. Enhanced prolyl-hydroxylase inhibition improved cardiac repair and heart function.