Inhibition of BCL-xL with the small molecule UBX1967 targets Col1a1-positive endothelial cells in ischemic retinopathy

Abstract

Purpose : Pathological neovascularization (NV) remains one of the main challenges in the treatment of proliferative diabetic retinopathy (PDR). Current therapies for PDR target NV yet often lead to off-target effects on healthy blood vessels. We previously demonstrated that pathological vasculature in the retina selectively engages programs of cellular senescence. This study aims to understand the molecular signatures of diseased vessels in order to elucidate new drug targets.

Methods : Ischemic retinopathy was studied in the proxy mouse model for PDR, oxygen-induced retinopathy (OIR) using C57Bl/6J mice. Pups were exposed to 75% O₂ from post-natal day (P)7-P12 and 21%O₂ P12-P17. The BCL-xL small molecule inhibitor, UBX1967, was administered intravitreally at P12. In vitro studies were performed using human retinal microvascular endothelial cells. Quantitative PCR, single-cell (sc) and bulk RNA-Seq were used for transcriptomic analyses. Protein expression was studied by means of Western blot or tissue immunolabelling. All animal studies complied with the ARVO Statement for the Use of Animals in Ophthalmic and Vision Research and were approved by institutional ethical committees.

Results : Pathological neovascularization is associated with expression of the anti-apoptotic BCL-2 protein family members. Senolysis via inhibition of BCL-xL suppresses neovascularization, accelerates the recovery of ischemic regions and is accompanied by a decrease of the senescence-associated secretory phenotype. Using scRNA-Seq, we observe an OIR-specific subpopulation of Col1a1-positive endothelial cells that localizes to regions of pathological NV and that is not present after BCL-xL inhibition.

Conclusions : Inhibition of BCL-xL with UBX1967 suppresses retinal pathological NV and targets Col1a1-positive subpopulations of endothelial cells. These data highlight the use of senolytics as potential therapies for PDR.

This is a 2021 ARVO Annual Meeting abstract.