Investigating the role of Gli1 in the development of choroidal neovascularisation

Abstract

Uncontrolled inflammation in the retina can lead to fibrovascular membrane formation, which can cause severe structural damage to the retina thus leading to blindness. The pathogenesis of retinal fibrosis is not completely understood. Recent research has implicated the Hedgehog pathway transcription factor Gli1 in the development of fibrosis. This study aims to elucidate the role of Gli1 in the development of fibrovascular membranes in the retina utilising fluorescent reporter mice. Gli1CreERT2 mice were crossed with ROSA26TdTomato mice to produce Tomato x Gli1 crossbreeds. 6‐7 week old Heterozygous Tom x Gli1 mice received 100 mg/kg Tamoxifen daily (I.P.) for 5 days. Mice were monitored for 80 days to determine the duration Gli1‐Tomato expression. Eyes and other organs were collected for immunofluorescent staining. Tom x Gli1 mice received 4–5 laser burns per eye to induce choroidal neovascularisation and were monitored over 21 days to assess the expression of Gli1 in the injured retina using fundus imaging and immunofluorescent staining. Expression of Gli1‐Tomato was detected as far 80 days in the eye, predominantly in the choroid, sclera, cornea and ciliary body. Immunofluorescent staining displayed co‐expression of Gli1 with CD31+, NG2+, and Collagen 4+ blood vessels. Fundus imaging of CNV lesions displayed expression of Gli1‐tomato around the lesion. Immunostains of cryosections showed co‐expression of Gli1 with blood vessel markers in choroidal lesions. Gli1+ cells are expressed throughout the eye, most notably with blood vessels, and may contribute to the development of choroidal lesions in CNV.