Late-onset glaucoma in Yap conditional knockout mouse
Glaucoma is an optic neuropathy often referred to as "the silent thief of sight", due to its late diagnosis, which is generally made when degeneration of the optic nerve and retinal ganglion cells is already well under way. It is thus of utmost importance to have a better understanding of the disease, and to investigate more deeply the early causes of glaucoma. The transcriptional coactivator YAP recently emerged as an important regulator of eye homeostasis and is drawing attention in the glaucoma research field. Here we show that Yap conditional knockout mice (Yap cKO), in which the deletion of Yap is induced in both Muller glia (i.e. the only retinal YAP-expressing cells) and the non-pigmented epithelial cells of the ciliary body, exhibit breakdown of the aqueous-blood barrier accompanied by progressive collapse of the ciliary body as we observed in human uveitic patients. In addition, aged Yap cKO mice harbor glaucoma features, including alteration of glutamate recycling, deregulation of key homeostatic Muller-derived proteins, retinal vascular defects, optic nerve degeneration, and retinal ganglion cell death. Together, our findings reveal the essential role of YAP in preserving the ciliary body and the retinal ganglion cells, thereby preventing the onset of glaucoma features.