Abstract
Purpose :
Delayed retinal vascularization of immature retinas (phase I) is the driving force of late-stage retinopathy of prematurity (ROP), a leading cause of blindness in children. Postnatal hyperglycemia within the first few weeks of life is a significant risk factor for ROP. We aim to examine retinal metabolic responses in mice modeling hyperglycemia-associated phase I ROP.
Methods :
Hyperglycemia was induced with intraperitoneal (i.p.) injection of streptozotocin (STZ) in mice from postnatal (P) day 1 to 9. At P10, reteinal vessel growth was delayed. Single-cell suspensions were prepared from mouse retinas by using Worthington papain dissociation system (n=3 mice per group). A retinal cell barcoded library was prepared at the Single Cell Core at Harvard Medical School (HMS), sequenced at Biopolymer Facility at HMS, and aligned to the mouse genome at Harvard Chan Bioinformatics core. The downstream clustering analysis was performed using R package ‘Seurat’ (version 3.2.2), genes and cells were filtered so only cells with more than 300 genes detected or genes expressed in more than 10 cells were kept. The gene enrichment analysis was performed using ‘enrichGO’ function from R package ‘clusterProfiler’ and mouse annotation database ‘EnsDb.Mmusculus.v79’. The p-value was adjusted using Benjamini & Hochberg method with a cutoff of 0.05 on the enrichment tests.
Results :
In mice with phase I ROP, there was a robust down-regulation of genes involved in metabolic pathways in rod, cone, bipolar and amacrine cell clusters. The major metabolic pathways involved are generation of precursor metabolites and energy, ATP metabolic process, cellular respiration, and oxidative phosphorylation (p<0.001). There was an up-regulation in genes involved in visual development, such as visual perception, eye development, axon development, and synapse organization related gene-ontology terms in rod, cone, bipolar and amacrine cell clusters of phase I ROP retinas. In Müller glia, genes involved in energy production-related pathways were downregulated, while genes involved in gliogenesis, axon development and angiogenesis-related pathways were upregulated.
Conclusions :
We found that mice with phase I ROP experienced metabolic stress in retinal neurons and glia. Retinal remodeling may occur as compensatory responses. Modulating metabolic pathways may restore cellular homeostasis and prevent progression to severe ROP in premature infants.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.