Abstract
Purpose :
Pathological retinal neovascularization (PRNV) in proliferative diabetic retinopathy and retinopathy of prematurity presents a clinical challenge. This study investigates the role of bone morphogenetic protein (BMP) signaling in PRNV, with a focus on epigenetic modifications.
Methods :
The oxygen-induced retinopathy (OIR) mouse model was utilized to investigate BMP signaling. Experimental groups included OIR mice treated with Noggin (a BMP inhibitor) or vehicle via intraperitoneal injection from postnatal day 12-16. Capillary degeneration and neovascularization were assessed at p17 in flat-mount retinas using isolectin-B4 staining. Immunostaining of retinal sections evaluated BMP2, BMP4, and ALK3 localization. In vitro experiments involved human retinal endothelial cells (HRECs) treated with BMP2 (50ng/ml) or hypoxia (1% O2) for 48 hours. The impact of BMP2 on vascular endothelial growth factor (VEGF) was assessed through ELISA. MicroRNA (miRNA) expression was analyzed using GeneChip miRNA 3.0 array. DNA methylation of HRECs was quantified using a methylation assay colorimetric kit.
Results :
Noggin-treated OIR mice exhibited a significant reduction in capillary drop-out and neovascularization (p < 0.01). Immunostaining revealed an upregulation of BMP2, BMP4, and ALK3 expression in retinal vessels. BMP2 treatment of HRECs elevated VEGF production. MiRNA array analysis showed that 4% of miRs were significantly altered by BMP2, and around 5% by hypoxia, including miRNAs linked to VEGF signaling and angiogenesis. Specifically, BMP2 downregulated miR4521, miR769-3p, miR23b-5p, miR3195, miR6781-5p, while upregulating miR126-3p, miR921, miR7515, miR29c, and miR20b-5p. Interestingly, BMP2 and hypoxia induced similar effects on certain miRs, such as miR769-3p, miR23b, and miR20b. The DNA methylation assay demonstrated a statistically significant reduction induced by BMP2.
Conclusions :
Our findings suggest the potential involvement of BMP signaling in the pathogenesis of PRNV, potentially mediated through epigenetic modifications, including DNA hypomethylation and dysregulation of miRNA.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.