Diabetic retinopathy (DR) is a leading cause of vision loss in working-age adults and often progresses to proliferative diabetic retinopathy (PDR) with irreversible complications. Anti–vascular endothelial growth factor (VEGF) therapy remains the first-line treatment; however, resistance poses a significant challenge, necessitating alternative therapeutic targets. This study explores the role of angiopoietin-like protein 4 (ANGPTL4) in PDR pathogenesis, emphasizing vascular-immune-lymphatic interactions. We found significantly elevated ANGPTL4 and VEGF-C levels in the vitreous humor of patients with PDR, which were not affected by anti-VEGF therapy. In vivo, full-length ANGPTL4 and its C-terminal fragment promoted pathological angiogenesis and lymphatic-like remodeling in diabetic murine retinas, characterized by increased lymphatic vessel endothelial hyaluronan receptor 1, prospero homeobox 1, and VEGF receptor 3 (VEGFR3) expression. Single-cell sequencing further revealed ANGPTL4-driven immune dysregulation, with abnormal infiltration of CD4+ T cells and dendritic cells. Knockdown of ANGPTL4 in mice with oxygen-induced retinopathy alleviated retinal hypoxia, neovascularization, and vascular leakage. Mechanistically, retinal hypoxia markedly increased ANGPTL4 expression levels in the retina, which activated the activator protein-1 (AP-1) transcription factor complex and promoted Cd83 transcription in mouse heart microvascular endothelial cells. Additionally, ANGPTL4 bound to neuropilin-1 (NRP1)/VEGFR3, driving human lymphatic endothelial cell proliferation and lymphatic vessel ingrowth from the optic nerve sheath into the retina, a finding that suggests a novel pathway independent of angiopoietin-Tie signaling. These findings establish ANGPTL4 as a key mediator of immune–vascular interactions in PDR and a potential therapeutic target to address both pathological angiogenesis and lymphatic dysfunction.
- Some patients with proliferative diabetic retinopathy (PDR) have poor responses to anti–vascular endothelial growth factor (anti-VEGF) therapy. This situation highlights the need for additional therapeutic approaches.
- In proliferative diabetic retinopathy, what is the role of ANGPTL4 that differs from VEGF?
- We found that ANGPTL4 is elevated in the vitreous humor of patients with PDR who are poorly responsive to anti-VEGF therapy. ANGPTL4, particularly its C-terminal fragment, causes retinal lymphatic-like remodeling in diabetic mice.
- This study provides novel insights into the complex interplay between immune activation, neovascularization, and lymphatic-like remodeling in PDR. Our findings deepen our understanding of PDR pathophysiology and propose a promising therapeutic target.
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