Posted on December 19, 2001 at 4:50 p.m.
BIRMINGHAM, AL — Researchers at UAB (University of Alabama at Birmingham) have found that the addition of a particular gene to certain non-neural cells in the retina can spur the growth of new neural retinal cells, potentially having benefit for eye diseases such as age-related macular degeneration (AMD).
Neurons in the retina and throughout the central nervous system form during embryonic development, and if damaged, do not have the capacity to regenerate. In a paper published in the December 18th edition of the Proceedings of the National Academy of Science, the UAB team reports that the addition of the gene neurogenin (ngn2) to non-neural, retinal pigment epithelial (RPE) cells prompted the RPE cells to differentiate, or develop, into the pre-cursors of neural retina cells, particularly photoreceptor cells and ganglion cells.
“Eye diseases such as macular degeneration can be caused by loss or damage to photoreceptor or ganglion cells in the retina,” says Shu-Zhen Wang, Ph.D., assistant professor of ophthalmology and lead author of the paper. “Our findings indicate that it may be possible to replace damaged photoreceptor and ganglion cells by creating new photoreceptor and ganglion cells from RPE cells.
Neural retinal cells are the building blocks of vision as photoreceptor cells transform light into electrophysiological signals that are transmitted to the brain by ganglion cells.
“Science has been hoping to identify renewable sources of cells that have the potential to differentiate into particular types of neurons or neural precursors for cell-based therapies,” says Wang. “Our study showed that cultured RPE cells could be guided toward retinal neuron pathways by ngn2, offering a potential source of cells for generating retinal neurons.”
Wang’s team observed that in the developing chick retina, ngn2 was expressed in a sub-group of proliferating progenitor cells. The main products of the induced neurogenesis were cells resembling young photoreceptor cells and cells resembling retinal ganglion cells.
“The generation of multiple cell types suggests that ngn2 induces various retinal pathways,” says Wang. “Our finding that ngn2 can instruct non-neural retinal pigment epithelial cells to differentiate toward retinal neurons demonstrates one possible way to induce new retinal cell growth, and potentially serve as a therapy for a variety of vision disorders.”
Wang cautions that while promising, this is laboratory research in the very early stages and is years away from any potential human interaction.