| First Author | Wang Z | Year | 2014 |
| Journal | Invest Ophthalmol Vis Sci | Volume | 55 |
| Issue | 6 | Pages | 3820-32 |
| PubMed ID | 24845641 | Mgi Jnum | J:230017 |
| Mgi Id | MGI:5755224 | Doi | 10.1167/iovs.13-13396 |
| Citation | Wang Z, et al. (2014) PPARalpha regulates mobilization and homing of endothelial progenitor cells through the HIF-1alpha/SDF-1 pathway. Invest Ophthalmol Vis Sci 55(6):3820-32 |
| abstractText | PURPOSE: The mechanism for the antiangiogenic activity of peroxisome proliferator-activated receptor alpha (PPARalpha) remains incompletely understood. Endothelial progenitor cells (EPC) are known to participate in neovascularization (NV). The purpose of this study was to investigate whether PPARalpha regulates EPC during retinal NV. METHODS: Retinal NV was induced by oxygen-induced retinopathy (OIR). Mice with OIR were injected intraperitoneally with the PPARalpha agonist fenofibric acid (FA) or with adenovirus expressing PPARalpha (Ad-PPARalpha). Flow cytometry was used to quantify circulating and retinal EPC. Serum stromal cell-derived factor 1 (SDF-1) levels were measured by ELISA. Hypoxia was induced in primary human retinal capillary endothelial cells (HRCEC) and mouse brain endothelial cells (MBEC) by CoCl2. Levels of SDF-1 and hypoxia-inducible factor 1 alpha (HIF-1alpha) were measured by Western blotting. RESULTS: Fenofibric acid and overexpression of PPARalpha attenuated the increase of circulating and retinal EPC, correlating with suppressed retinal NV in OIR mice at P17. The PPARalpha knockout enhanced the OIR-induced increase of circulating and retinal EPC. Fenofibric acid decreased retinal HIF-1alpha and SDF-1 levels as well as serum SDF-1 levels in the OIR model. In HRCEC, PPARalpha inhibited HIF-1alpha nuclear translocation and SDF-1 overexpression induced by hypoxia. Further, MBEC from PPARalpha(-/-) mice showed more prominent activation of HIF-1alpha and overexpression of SDF-1 induced by hypoxia, compared with the wild-type (WT) MBEC. PPARalpha failed to block SDF-1 overexpression induced by a constitutively active mutant of HIF-1alpha, suggesting that regulation of SDF-1 by PPARalpha was through blockade of HIF-1alpha activation. CONCLUSIONS: Peroxisome proliferator-activated receptor alpha suppresses ischemia-induced EPC mobilization and homing through inhibition of the HIF-1alpha/SDF-1 pathway. This represents a novel molecular mechanism for PPARalpha's antiangiogenic effects. |
