Formyl Peptide Receptor 1 Inhibits Reparative Angiogenesis and Aggravates Neuroretinal Dysfunction in Ischemic Retinopathy.

Purpose: Ischemic retinopathy is the major cause of vision-threatening conditions. Inflammation plays an important role in the pathogenesis of ischemic retinopathy. Formyl peptide receptor 1 (FPR1) has been reported to be implicated in the regulation of inflammatory disorders. However, the role of FPR1 in the progression of ischemic retinal injury has not been fully explained.

Methods: The activation of FPR1 was measured by real-time PCR and western blotting in the retina of OIR. The effect of FPR1 on the expression of inflammatory cytokines and relevant pro-angiogenic factors was assessed between wild-type and FPR1-deficiency OIR mice. The impact of FPR1 on retinal angiogenesis was evaluated through quantifying retinal vaso-obliteration and neovascularization between FPR1^+/+ and FPR1^-/- OIR mice. At last, the neuronal effect of FPR1 on the ischemic retina was investigated by ERG between wild-type and FPR1-deficient OIR mice.

Results: The expression of FPR1 significantly increased in the retina of OIR. Furthermore, FPR1 deficiency downregulated pro-inflammatory and pro-angiogenic factors. Ablation of FPR1 suppressed the retinal pathological neovascularization and promoted reparative revascularization, ultimately improving retinal neural function after ischemic injury.

Conclusion: In ischemic retinopathy, FPR1 aggravates inflammation and inhibits reparative angiogenesis to exacerbate neuronal dysfunction.