VEGFR1-mediated pericyte ablation links VEGF and PlGF to cancer-associated retinopathy

Area of Science:

• Ophthalmology
• Molecular Biology
• Angiogenesis Research

Background:

• Vascular Endothelial Growth Factor (VEGF) signaling is crucial for vascular health and cellular interactions.
• Dysfunction in the VEGF pathway is implicated in the development of retinopathy.
• Pericytes play a vital role in stabilizing retinal vasculature.

Purpose of the Study:

• To investigate the role of VEGF and placental growth factor (PlGF) in pericyte regulation within the mature retinal vasculature.
• To elucidate the specific VEGF receptor (VEGFR1 or VEGFR2) involved in VEGF/PlGF-induced pericyte loss.
• To evaluate the therapeutic potential of targeting VEGFR1 for retinopathy treatment.

Main Methods:

• Systemic delivery of VEGF and PlGF using protein implantation, tumors, and adenoviral vectors in a preclinical model.
• Assessment of pericyte coverage in retinal vasculature.
• Pharmacological blockade of VEGF receptor 1 (VEGFR1) and VEGF receptor 2 (VEGFR2).

Main Results:

• Systemic VEGF and PlGF administration led to pericyte ablation from mature retinal vessels via VEGFR1 signaling, increasing vascular leakage.
• VEGF receptor 2 (VEGFR2) was predominantly found in nonvascular retinal cells (photoreceptors and ganglion cells).
• Blockade of VEGFR1, but not VEGFR2, significantly restored pericyte saturation in retinal vessels.

Conclusions:

• VEGF and PlGF contribute to retinopathy, potentially including cancer-associated retinopathy, by inducing pericyte loss through VEGFR1.
• VEGFR1 mediates the detrimental effects of VEGF/PlGF on retinal vasculature.
• VEGFR1 represents a promising therapeutic target for antiangiogenic strategies in treating retinopathy.