Reminding retinal cells to regenerate

Retinal cells called Müller glial (MG) cells exist in humans and zebrafish, but function differently in the two species.

In zebrafish, these cells act like retinal stem cells and routinely replace damaged retinal neuronal cell types, including ganglion and photoreceptor cells, which are lost in glaucoma and macular degeneration, respectively.

In mammals, MG cells take on stem cell-like properties only if severe physical injury to the retina occurs. Even then, just a small number of cells are replenished. Reactivating human MG cells to behave as stem cells holds potential as a treatment for blindness-causing diseases.

Researchers led by Bo Chen, Ph.D., associate professor of ophthalmology and visual science, and of neuroscience, found they could initiate stem cell behavior in mice MG cells by activating the Wnt/Lin28 signaling pathway without causing damage to the retina. As described in Cell Reports, published Sept. 27, they transferred the genes ß-catenin or Lin28 into adult mouse retinas, causing MG cells to behave like stem cells. About 5 percent of MG cells turned into retinal neuronal cells, but that was just a first step, says Chen. “Now we need to guide the cell cycle-reactivated MG cells to differentiate into ganglion or photoreceptor cells,” Chen says.