Abstract
Purpose :
Adeno-associated virus (AAV) has been widely used as a gene delivery vehicle in the ocular gene therapy. It has been proved in animal models and human that many AAVs can efficiently transduce different cell layers in the retina. However, there are very few reports to show that AAVs could successfully transduce the anterior segment of the eye, especially the trabecular meshwork cells. Some Self-complimentary AAV, such as self-complimentary AAV2 (scAAV2), had been shown robust transduction in the anterior segment cells of mouse, rat and monkey. Unfortunately, for the self-complimentary AAV, the maximum package genome size is approximate 2.2kbp, which is less than half of the package capacity of single strand AAV vectors. In previous studies, we showed that an ancestral AAV, Anc80, which was developed in our lab by in silico ancestral sequence reconstruction, can achieve fast onset and long-term stable expression in retinal cells. Here we want to explore the tropism and transduction efficiency of the ancestral AAV vector (Anc80) in the anterior segment of mice eyes, and compare it with some other contemporary AAVs.
Methods :
We selected three different AAV vectors (single strand AAV2-ssAAV2, scAAV2 and Anc80), carrying eGFP reporter gene driven by CMV promoter. The viral vectors were injected into wild type C57Bl/6 mouse eyes either via anterior chamber injection at the dose of 1×109 particles, or via intravitreal injection at the dose of 2×109 particles. At day 28 post injection, mice eyeballs were collected and sectioned to examine the GFP expression in the anterior segment by using confocal microscopy.
Results :
All the three AAV vectors can transduce cornea, trabecular meshwork and ciliary body by anterior chamber injection. According to the GFP expression level and expression area, in cornea, Anc80>ssAAV2>scAAV2; and in the trabecular meshwork and ciliary body, Anc80>scAAV2>ssAAV2. Via intravitreal injection, GFP expression was detected in cornea and ciliary body in the Anc80 group, while no GFP expression in cornea or ciliary body was found in the ssAAV2 group.
Conclusions :
Anterior chamber or intravitreal injections of Anc80 efficiently transduce all components of the mouse anterior segment. These results inform future studies that aim to deliver therapeutics in disease models affecting the cornea, iris, or ciliary body, such as glaucoma.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.