Abstract
Purpose :
Retinopathy of prematurity (ROP) poses a threat of blindness in premature infants due to abnormal retinal blood vessel growth, with its underlying mechanism still not fully understood. This study aims to delve into the involvement of glucose-6-phosphate dehydrogenase (G6PD) in the pathological angiogenesis of the retina, particularly in the context of oxygen-induced retinopathy (OIR), an experimental model mimicking ROP.
Methods :
Using postnatal day (P)7 C57BL/6 mice exposed to 75% oxygen for 5 days followed by normal air for another 5 (OIR model), the study examined G6PD protein expression and enzymatic activity in the retina through immunofluorescence staining, Western blot, and commercial kit. Human retinal endothelial cells (HREC) were cultured for tube formation. G6PD inhibitor DHEA and siRNA were introduced into extracellular vehicles (EVs) derived from human induced pluripotent stem cells (hiPSC)-ECs. In-vivo effects on ischemia-induced retinal angiogenesis or neovascularization (NV) were quantified using ImageJ software.
Results :
G6PD protein levels increased in the retinas of P14 and P17 mice with OIR compared to P12 mice in similar conditions and those in normal air. Ischemia heightened G6PD enzymatic activity in P14 and P17 retinas compared to P12, with no changes observed under normal conditions. G6PD was notably concentrated in sprouting endothelial cells (ECs) during pathological retinal angiogenesis induced by ischemia. Knocking down G6PD inhibited retinal NV and vessel sprouting. G6PD inhibition by DHEA impacted cell migration, tube formation, and critical signaling pathways (AKT, eNOS) in HREC cultures. hiPSC-derived EVs were intravitreally injected and targeted to the retinal vasculatures. EVs loaded with DHEA and siRNA demonstrated therapeutic effects on HREC tube formation in vitro. The in-vivo assessments of retinal NV are ongoing.
Conclusions :
G6PD emerges as a crucial player in ischemia-induced retinal NV in the OIR model, suggesting its potential as a therapeutic target for treating ROP.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.