The inner and outer blood-retina barriers (BRBs) are formed by tight junctions between adjacent endothelial or retinal pigment epithelial (RPE) cells. Breakdown of BRBs is a major pathological change in age-related macular degeneration, diabetic retinopathy, retinopathy of prematurity, and uveitis. While previous studies have yielded a better understanding about the roles of the inner BRB under physiological and pathological conditions, surprisingly little is known about the regulation and pathophysiology of the outer BRB. Since the outer BRB is responsible for ~85% of blood circulation to the retina, it is unimaginable that ischemia-induced pathological change in the outer BRB plays an insignificant role in the overall pathology of retinochoroidal vascular diseases. To investigate the mechanisms of outer BRB breakdown and to test the concept of inhibiting outer BRB permeability as a therapeutic strategy for retinochoroidal vascular diseases, we have prepared gene knockout systems for the mouse RPE and M?ller glia, cells that regulate the function of both inner and outer BRBs through vascular endothelial growth factor (VEGF-A). Using these conditional gene knockout systems, we have disrupted VEGF and its receptor (VEGFR2) in the mouse RPE and have generated mice with VEGF disruption in the M?ller cells.
In Specific Aim 1, we will test our hypothesis that outer BRB breakdown is a significant contributor to diabetes/ischemia-induced overall retinal "vascular leakage" through autocrine VEGF/VEGF-R2 signaling in the RPE by measuring the total retinal vascular leakage, the number of significant breakpoints in the outer BRB, and the quantity of outer BRB-specific leakage in the RPE-specific VEGF and VEGFR2 knockout mice after inducing ischemia or diabetes.
In Specific Aim 2, we will test the concept of inhibiting outer BRB permeability as a therapeutic strategy for uveitis by examining the total retinal vascular leakage, the number and severity of retinal detachment, the quantity of outer BRB-specific leakage, and the expression of inflammatory biomarkers in the RPE-specific VEGFR2 knockout mice after inducing uveitis. As a control for inner BRB breakdown, we will also measure the same parameters in uveitic M?ller cell- specific VEGF knockout mice.
In Specific Aim 3, we will determine the molecular mechanism of diabetes/ischemia-induced outer BRB breakdown by investigating the biochemical pathway governing the regulation of tight-junction proteins.

Public Health Relevance

This application is relevant to an important public health issue: the pathogenic mechanism of leading causes of blindness: diabetic retinopathy, retinopathy of prematurity, and uveitis. Our study will focus on the regulatory mechanism and the pathophysiology of blood-retina barriers.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Research Project (R01)
Project #
5R01EY020900-03
Application #
8323406
Study Section
Biology and Diseases of the Posterior Eye Study Section (BDPE)
Program Officer
Shen, Grace L
Project Start
2010-09-01
Project End
2014-08-31
Budget Start
2012-09-01
Budget End
2013-08-31
Support Year
3
Fiscal Year
2012
Total Cost
$355,200
Indirect Cost
$115,200
Name
University of Oklahoma Health Sciences Center
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
878648294
City
Oklahoma City
State
OK
Country
United States
Zip Code
73117
Fu, Shuhua; Zhu, Meili; Wang, Changyun et al. (2014) Efficient induction of productive Cre-mediated recombination in retinal pigment epithelium. Mol Vis 20:480-7
Fu, Suhua; Zhu, Meili; Ash, John D et al. (2014) Investigating the role of retinal Müller cells with approaches in genetics and cell biology. Adv Exp Med Biol 801:401-5
Liu, Dan; Xiong, Si-Qi; Shang, Lei et al. (2014) Expression of netrin-1 receptors in retina of oxygen-induced retinopathy in mice. BMC Ophthalmol 14:102
Dong, Shuqian; Liu, Yan; Zhu, Meili et al. (2014) Simplified system to investigate alteration of retinal neurons in diabetes. Adv Exp Med Biol 801:139-43
Nasonkin, Igor O; Merbs, Shannath L; Lazo, Kevin et al. (2013) Conditional knockdown of DNA methyltransferase 1 reveals a key role of retinal pigment epithelium integrity in photoreceptor outer segment morphogenesis. Development 140:1330-41
Luo, Ling; Uehara, Hironori; Zhang, Xiaohui et al. (2013) Photoreceptor avascular privilege is shielded by soluble VEGF receptor-1. Elife 2:e00324
He, Chaoyong; Zhu, Huaiping; Zhang, Wencheng et al. (2013) 7-Ketocholesterol induces autophagy in vascular smooth muscle cells through Nox4 and Atg4B. Am J Pathol 183:626-37
Zhu, Meili; Bai, Yanyan; Zheng, Lixin et al. (2012) Presence of RPE-produced VEGF in a timely manner is critical to choroidal vascular development. Adv Exp Med Biol 723:299-304
Xu, Huizhuo; Liu, Jiaolian; Xiong, Siqi et al. (2012) Suppression of retinal neovascularization by lentivirus-mediated netrin-1 small hairpin RNA. Ophthalmic Res 47:163-9
Le, Yun-Zheng (2011) Conditional gene targeting: dissecting the cellular mechanisms of retinal degenerations. J Ophthalmol 2011:806783

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