RUNX1 promotes angiofibrosis in models of angiogenic eye disease

Abstract

Purpose : Pathologic angiofibrosis is characterized by vision-disrupting fibrovascular membranes (FVMs) found in diseases including proliferative diabetic retinopathy (PDR) and wet age-related macular degeneration (AMD). While VEGF signaling has been implicated, the fibrosis that characterizes FVMs is not VEGF mediated. The purpose of this study was to evaluate the role of the transcription factor RUNX1 in angiofibrotic progression through the mesenchymal transition of endothelial cells to a fibroblast phenotype (Endo-MT).

Methods : Patient-derived FVMs were evaluated by immunofluorescence (IF), and single cell RNA-seq analysis using the 10x Genomics platform. Primary cultures of human microvascular retinal endothelial cells (HMRECs) were used to assess the effects of RUNX1 expression through TNFα induction and transient manipulations of RUNX1 expression. Transcriptional activity and gene expression related to Endo-MT were determined via molecular biological techniques. Two mouse models, a laser-induced choroidal neovascularization (L-CNV) and the Kimba (TrVEGF029) mouse model of genetically induced VEGF overexpression, were used to evaluate the effects of systemic pharmacological RUNX1 inhibition. Animals were evaluated by fundoscopy, fluorescein angiography and IF.

Results : Colocalization of RUNX1 and mesenchymal proteins in FVMs were visualized by IF. Gene expression profiling of FVMs by scRNA-seq supported the presence of cell populations undergoing Endo-MT. In HMRECs, increases in RUNX1 expression were concomitant with changes in expression of endothelial, mesenchymal markers and collagen, (p<0.05). These observations were coincident with increased RUNX1 transcriptional activity. RUNX1 inhibition was sufficient to attenuate leakage and lesion size in L-CNV mice (p<0.001) Remarkably, in Kimba TrVEGF029 mice systemic RUNX1 inhibition also significantly improved retinal pathologies relative to untreated controls (p< 0.01)

Conclusions : These findings provide insight into how RUNX1 may contribute to the progression of angiofibrosis via Endo-MT, and implicates RUNX1 as a putative angiofibrotic switch. Therapeutics targeting RUNX1 may hinder the onset of vision threatening complications associated with angiofibrotic diseases of the eye.

This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.

 

Figure 1. RUNX1 induces Endo-MT in models of Angiofibrosis. (A) scRNA-seq of patient-derived FMVs. (B) Endo-MT following TNFα treatment in HMRECs (C). RUNX1 inhibition attenuates pathology in Kimba mice.