Abstract
Purpose :
Pathological increases in vascular permeability lead to oedema and swelling, causing a host of retinal and neurological disorders. Few barrier-enhancing factors have been discovered to specifically increase barrier integrity and make vessels resistant to fluid leakage. In this study, we explore the effects of IL-36 on angiogenic processes and vascular permeability in vivo and in vitro.
Methods :
The ability of IL-36 cytokines to modulate angiogenic properties in vitro was examined in human retinal microvascular endothelial cells using wound healing, proliferation and tube formation assays. Flux assays were performed to analyse the monolayer integrity of the cells following IL-36 stimulation. RNA sequencing, qPCR and western blot were used to ascertain potential mechanisms underlying these functional readouts. In vivo, laser induced choroidal neovascularisation were performed in C57BL/6J mice injected intravitreally with vehicle or IL-36β. Fluorescein angiography was used to assess the permeability of these CNV and the surrounding retinal microvasculature before tissue was harvested and analysed to ascertain if IL-36 altered the volume of CNV.
Results :
IL-36β enhanced endothelial cell barrier function, reducing vascular permeability. IL-36 cytokines also induced primary endothelial cell proliferation, migration, and tube formation in vitro. Importantly, we demonstrate that the IL-36 signalling axis has potential to be useful clinically for reducing microvascular leakage, as the pro-angiogenic features of IL-36 in vitro are uncoupled from the potent ability of IL-36 to enhance vascular integrity in adult mice in vivo in an acute setting. Mechanistically IL-36 regulates endothelial cell tight/adherens junctions, in addition to inducing vessel remodelling and maturation providing a stabilised vascular network. Network analysis of RNA sequencing data support these functional assays.
Conclusions :
Our data present IL-36 cytokines as novel promoters of vascular integrity, with barrier enhancing properties that prevent pathological vascular permeability.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.