Retinopathy of Prematurity (ROP) is a potentially blinding condition of low birth weight premature children that affects over 50,000 children worldwide each year. The incidence of ROP is on the rise, primarily due to improvements in neonatal care in developing nations. The underlying pathophysiology of ROP is a consequence of ischemia of the peripheral retina. Ischemia can lead aberrant neovascularization at the border between the vascularized and non-vascularized retina. These vessels are incompetent and may lead to edema, bleeding, fibrosis, and can ultimately progress to a tractional retinal detachment and blindness. Importantly, parallel vascular changes are also responsible for visual morbidity in other diseases of the retinal vasculature, including diabetic retinopathy (DR), which affects 25.8 million Americans and is the leading cause of blindness in the working-age population. Changes in the function of the retinal vascular endothelial cells, including neovascularization and vascular leakage, are central to the disease phenotype, yet little is known about the molecular changes that occur in these cells that lead to their dysfunction. To investigate these molecular changes, we have purified the vascular endothelial cells during key timepoints in oxygen induced retinopathy (OIR), a mouse model of ischemic vasculopathy, and evaluated the transcriptome. These data identified PDLIM1 as a molecule that is upregulated specifically in the vascular endothelial cells at the time of leakage and proliferation. In tissue culture, expression of PDLIM1 results in a reduction of the barrier properties. We have now generated PDLIM1 knockout and overexpression mouse strains, and propose to test the role of PDLIM1 in retinal vascular permeability and proliferation. This work may identify PDLIM1 as a novel therapeutic target to prevent breakdown of the blood-retinal barrier and aberrant neovascularization in diseases of the retinal vasculature.
Vision loss in both Retinopathy of Prematurity and Diabetic Retinopathy can be due to leakage, bleeding, and growth of abnormal retinal blood vessels. We have identified PDLIM1 as a molecule that may be necessary for causing the retinal blood vessels to leak and proliferate in disease. We propose to test this hypothesis with the intention identifying a new therapeutic target to treat these conditions.