Research led by Emory Eye Center scientist Eldon E. Geisert, PhD, shows that a protein that affects corneal thickness might also be connected to glaucoma risk.
The study, conducted on mice, found that variations in the genes that code for a protein called POU6F2 correlated with corneal thickness. In the developing eye, nerve cells of the retina and cells of the cornea express POU6F2. When the researchers removed the gene that codes for POU6F2, the mice had thinner corneas than normal mice. They also learned that POU6F2 helps regulate the developing cornea and helps keep it healthy by replenishing corneal stems cells in adult mice.
In glaucoma, pressure builds in the eye and damages the optic nerve. If left untreated, glaucoma may ultimately lead to blindness. Thinner corneas are a well-known risk factor for one variation of the disease – primary open angle glaucoma (POAG). Geisert’s group demonstrated that the cells expressing POU6F2 are the most sensitive to injury. In collaboration with other research groups studying the human risk factors for glaucoma, POU6F2 is a good candidate for glaucoma risk in humans.
“We were very surprised by our findings,” Geisert says. “Almost everyone believes that the link between central corneal thickness and glaucoma is due to stiffness of the cornea and sclera – not because of a protein such as POU6F2 which controls gene expression. Thus, the link was not immediately obvious.”
“The specific role many proteins play in our body may differ from tissue to tissue,” he continues. “In the cornea, POU6F2 is involved with tissue development and marks the stem cells that maintain corneal integrity. But it appears to have a completely different role in the retina.”
Current research efforts are attempting to understand how POU6F2 might regulate the eye’s structure and increase a person’s risk of glaucoma. “Things we learn about POU6F2 and retinal ganglion cell susceptibility to injury may provide unique insights into methods to treat early phases of glaucoma,” he says.
“Glaucoma is a complex disease with many genetic and environmental factors influencing the patient population,” Geisert adds. “We hope that defining this link between central corneal thickness and glaucoma – and other aspects of POU6F2 – will aid in early detection of glaucoma and eventually lead to treatments that can halt the progression of this disease.”