Abstract
Norrin (NDP) and WNT7A/B induce and maintain the blood-brain and blood-retina barrier (BBB, BRB) by stimulating the Frizzled4-LDL receptor related protein 5/6 (FZD4-LRP5/6) complex to induce beta-catenin-dependent signaling in endothelial cells (ECs). Recently developed agonists for the FZD4-LRP5 complex have therapeutic potential in retinal and neurological diseases. Here, we use the tetravalent antibody modality F4L5.13 to identify agonist activities in Tspan12−/− mice, which display a complex retinal pathology due to impaired NDP-signaling. F4L5.13 administration during development alleviates BRB defects, retinal hypovascularization, and restores neural function. In mature Tspan12−/− mice F4L5.13 partially induces a BRB de novo without inducing angiogenesis. In a genetic model of impaired BRB maintenance, administration of F4L5.13 rapidly and substantially restores the BRB. scRNA-seq reveals perturbations of key mediators of barrier functions in juvenile Tspan12−/− mice, which are in large parts restored after F4L5.13 administration. This study identifies transcriptional and functional activities of FZD4-LRP5 agonists.
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•Frizzled4-LRP5 agonist mimics Norrin in retinal angiogenesis and barriergenesis•Induces de novo barrier formation in adult mice after failed barrier development•Proangiogenic effects are context-dependent and are limited to development•Transcriptional regulation of endothelial cell differentiation and transport
Biological sciences; Neuroscience; Molecular neuroscience; Omics; Transcriptomics