Ccl2/Cx3cr1-deficient mice: an animal model for age-related macular degeneration.

BACKGROUND/AIMS Senescent Ccl2-/- mice develop cardinal features of human age-related macular degeneration (AMD). Loss-of-function single-nucleotide polymorphisms within CX3CR1 are associated with AMD. METHODS We generated Ccl2-/-/Cx3cr1-/- [double-knockout (DKO)] mice and evaluated the eyes using fundoscopy routine histology, immunochemistry, biochemistry and proteomics. RESULTS At 6 weeks old, all DKO mice developed AMD-like retinal lesions such as abnormal retinal pigment epithelium cells, drusen, photoreceptor atrophy and choroidal neovascularization, which progressed with age and reversed with high omega-3 long-chain polyunsaturated fatty acid diet. N-retinylidene-N-retinylethanolamine (A2E), a major lipofuscin fluorophore, illustrated by an emission peak at approximately 600 nm, was significantly higher in DKO retinal pigment epithelium. Decreased ERp29 was found in the retina of DKO mice. CONCLUSION A broad spectrum of AMD pathologies with early onset and high penetrance in these mice implicate certain chemokines, A2E and endoplasmic reticulum proteins in AMD pathogenesis.