Abstract
Purpose :
To generate and optimize conditional gene knockouts of the trabecular meshwork (TM) and characterize the role of miRNAs in the homeostasis and physiology of the post-natal TM.
Methods :
To test the hypothesis that miRNAs play a role in the regulation of gene expression of cells in the anterior segment of the eye, we generated a targeted deletion of Dicer in the anterior chamber of the eye in two month old mice (n=7). This conditional dicer knockout was accomplished by intracameral injection of 5x106 pfu of an adenoviral vector expressing cre recombinase under the CMV promoter in Dicer1tm1Bdh/J mice, which contain loxP sites on either side of exon 23 of the Dicer gene. Intraocular pressures (IOPs) were evaluated using a TonolabTM tonometer and morphological changes observed in semithin sections and electron microscopy.
Results :
Loss of microRNA function by deletion of dicer in the anterior chamber resulted in increased intraocular pressures (IOPs) and morphological alterations in the TM 2 months after injection. The TM showed a noticeable increase in pigment accumulation and cells laden with pigment in the trabecular meshwork. The iris appears disordered with accumulation of large pigment-laden cells that appear to be migrating to the trabecular meshwork and suprachoroidal space.
Conclusions :
Targeted viral introduction of cre recombinase into the TM of a transgenic mouse with a lox-p flanked target gene can successfully delete this gene in a majority of TM cells. MiRNAs are important in the normal physiology of the TM and lack of them will lead to trabecular meshwork alterations and increased intraocular pressures (IOPs).
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.