Small pet-store fish with regenerative powers may help conquer sight loss in humans.

By Kris Dreessen

The National Eye Institute estimates that the number of people affected by eye diseases will increase significantly by 2050. Many of these disorders, such as age-related macular degeneration, result in the breakdown of the retina, which contains photoreceptor neurons that detect light and help move that information to the brain.

Humans can’t regenerate damaged photoreceptors, so the damage leads to vision loss. However, zebrafish — commonly found at pet stores — do regenerate photoreceptors. 

At Geneseo, Assistant Professor of Biology Travis Bailey and student researchers including Alexis Saunders ’19, are examining how zebrafish regenerate the cells. What they learn could help humans in the future.

Though they are only about an inch long, the zebrafish share similar retina development as humans, and similar genes in the eye. It is one of several animal species that inform of us of our own development, said Bailey. 

“All the living things in nature have some things about them in common, even invisible things,” he said. “The study of living things that at first glance may not necessarily seem related to you, like fruit flies or pet fish, have value in understanding how our bodies work.”

Zebrafish have adult cells in their eyes called Müller glial cells. Their main function is to carry waste from photoreceptors away from the eye and into the bloodstream. However, if a photoreceptor is damaged, Müller glial cells will proliferate, divide and some of its daughter cells will migrate to the damaged photoreceptor — and transform into new photoreceptors.

Through his research with other scientists, Bailey discovered that the fish’s physiology must create a new signal to direct the Müller glial cell to change and become something else — a stem cell that regenerates. 

“It’s part of the work I’m most proud of,” he said.

Bailey and his students are now examining the signal and how it functions, including if there is more than one signal, as well as studying the glial cells and what controls them. They have done so with the assistance of Geneseo Foundation grants for research.

“Because the genes and the retina of zebrafish are so similar to ours, an understanding of the differences in such signaling between humans and zebrafish following retinal damage could help us develop strategies to help our retina regenerate,” said Bailey. “Finding therapies to regenerate human retinal neurons could also lead to advances in neural regenerative medicine applications, such as brain injuries.”