Abstract
Purpose :
Retinal vein occlusion (RVO) induced damage of blood-retinal barrier (BRB), resulting in excessive accumulation of iron within retina and exacerbating iron metabolism pressure. It is worthy of noting that NADPH oxidase 4 (Nox4), a major source of reactive oxygen species (ROS), has been identified in retinal damage. Ferroptosis is a novel cell death form characterized by iron-dependent lipid peroxidation. Here we proposed that targeting Nox4 may hold therapeutic potential for attenuating breakdown of BRB and suppressing ferroptosis-related damage to retinal ganglion cells (RGC) in RVO.
Methods :
The anminal model of RVO was set up by photodynamic retinal venous thrombosis with both wild-type (Nox4+/+) and Nox4 deficient (Nox4-/-) mice. Single-cell transcritomic analysis were performed. Retinal vessel loss and leukostasis were measured by fluorescein angiography and ConA-lectin perfusion, respectively. Feroptosis-induced impairment of retinal neurovascular unit (NVU) was assessed by flatmount staining, immunofluoresence and western-blot analysis.
Results :
Clustering strategy of single-cell transcritomic analysis confirmed increased population of neutrophils and resident glias and reduced population of RGC and vascular endothelial cells after RVO. Of note, activation of oxidative stress and ferroptosis pathway after RVO were also identified by differntially expressed gene analysis. Retinal vein blockade with adherent leukocytes, activated gliosis and loss of RGC were observed in Nox4+/+ mice after RVO. These injuries of NVU were significantly ameliorated in Nox4-/- mice. Moreover, Nox4-/- RVO mice displayed attenuated iron loads, reduced lipid peroxidation, and up-regulated expression of ferritin heavy chain 1 and glutathione peroxidase 4.
Conclusions :
Taken together, these results provided in vivo evidence that Nox4 deficiency mitigated iron overload after RVO, and protected retinal NVU from ferroptosis-related damage.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.