Date of Award

6-2025

Degree Type

Thesis

Degree Name

Master of Science in Biomedical Sciences

First Advisor

Arturo Bravo Nuevo, Ph.D.

Second Advisor

Scott Dessain, M.D, Ph.D.

Third Advisor

Michael McGuinness, Ph.D.

Abstract

Retinopathy of Prematurity (ROP) is a leading cause of vision loss in premature infants, caused by high-oxygen therapy exposure postnatally for lung development. During this period, vascular endothelial growth factor (VEGF) expression is suppressed, inhibiting normal blood vessel growth. When premature infants transition back to a normal-oxygen environment, the metabolic demands of the retina exceed oxygen availability, inducing a state of relative hypoxia. This hypoxia triggers the upregulation of hypoxia-inducible factor 1-alpha (HIF-1α), which in turn drives the overexpression of VEGF and erythropoietin (EPO), leading to pathological neovascularization. N-Methyl-D-Aspartate Receptor (NMDAR) is a highly expressed excitatory receptor in the brain and retina. Previous studies suggest that NMDAR hyperactivation is a critical mediator of retinal pathologies, promoting aberrant angiogenesis and retinal cell death. To investigate the role of NMDAR in ROP, we utilized a monoclonal antibody (mAb) derived from a patient with anti-NMDAR encephalitis, targeting a distinct epitope of NMDAR. We hypothesize that mAb-based inhibition of NMDAR hyperactivation will reduce pathological retinal neovascularization in a murine model of ROP. A total of 39 C57BL/6J wild-type (WT) mice were used in this study. Neonatal mice were maintained in normoxic room air (21% O₂) from birth (P0) to postnatal day 7 (P7). Mice were then assigned to either remain in normoxic conditions or undergo hyperoxia (75% O₂) exposure from P7 to P12, followed by a return to normoxia on P12. On P14, when the mice opened their eyes, they received bilateral intravitreal injections of either the control 9H2 mAb (which lacks NMDAR specificity) or the experimental 5F5 mAb (which selectively binds the GluN1 subunit of NMDAR). On P17, mice were injected with 5 μL of Lycopersicon esculentum (Tomato) Lectin conjugated with DyLight 594 via retro-orbital injection to visualize the retinal vasculature. Retinas were subsequently flat-mounted and analyzed using AngioTool software to quantify explant area, vessel area, vessel percentage area, total number of junctions, junction density, total vessel length, total number of endpoints, and mean lacunarity to test if NMDAR inhibition significantly impacted retinal vascular development across oxygen conditions. Under hyperoxia, both control and anti-NMDAR mAb groups exhibited reduced vessel area and increased lacunarity compared to normoxic counterparts (*p <  0.05), indicating oxygen-induced vascular disruption. Anti-NMDAR treatment further reduced vessel area, vessel length, and junction density under both normoxia and hyperoxia, with significant increases in endpoints under hyperoxia (*p <  0.05). Notably, normoxic anti-NMDAR mice showed diminished vascular complexity, suggesting NMDAR’s role in normal angiogenesis. NMDAR activity supports physiological retinal angiogenesis and contributes to pathological vascular changes in oxygen-induced retinopathy (OIR). Targeted NMDAR inhibition disrupted normal vascular development but also attenuated disease-associated vascular features under hyperoxia. These findings identify NMDAR as a critical upstream regulator of retinal angiogenesis, offering a novel therapeutic target for early intervention in retinopathy of prematurity.

Download

Share

COinS