Myeloid-Derived Vascular Endothelial Growth Factor and Hypoxia-Inducible Factor Are Dispensable for Ocular Neovascularization
Objective—Ocular neovascularization (ONV) is a pathological feature of sight-threatening human diseases, such as diabetic retinopathy and age-related macular degeneration. Macrophage depletion in mouse models of ONV reduces the formation of pathological blood vessels, and myeloid cells are widely considered an important source of the vascular endothelial growth factor A (VEGF). However, the importance of VEGF or its upstream regulators hypoxia-inducible factor-1α and hypoxia-inducible factor-2α as myeloid-derived regulators of ONV remains to be determined.
Approach and Results—We used 2 mouse models of ONV, choroidal neovascularization and oxygen-induced retinopathy, to show that Vegfa is highly expressed by several cell types, but not myeloid cells during ONV. Moreover, myeloid-specific VEGF ablation did not reduce total ocular VEGF during choroidal neovascularization or oxygen-induced retinopathy. In agreement, the conditional inactivation of Vegfa, Hif1a, or Hif2a in recruited and resident myeloid cells that accumulated at sites of neovascularization did not significantly reduce choroidal neovascularization or oxygen-induced retinopathy.
Conclusions—The finding that myeloid cells are not a significant local source of VEGF in these rodent models of ONV suggests that myeloid function in neovascular eye disease differs from wound healing and other neovascular pathologies.
- choroidal neovascularization
- diabetic retinopathy
- macular degeneration
- myeloid cells
- vascular endothelial growth factor A
- Received September 4, 2015.
- Accepted November 12, 2015.
- © 2015 The Authors.
Arteriosclerosis, Thrombosis, and Vascular Biology is published on behalf of the American Heart Association, Inc., by Wolters Kluwer. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution, and reproduction in any medium, provided that the original work is properly cited.