Engineered, light-sensitive molecules introduced into a blind rodent’s eye resulted in vision, according to results from an interdisciplinary collaboration between numerous labs. The results could lead to treatments for people with inherited, blinding eye diseases such as retinitis pigmentosa, which affects 1 in every 3,000 individuals.
In past studies, researchers made a blind animal’s visual cells respond to light by introducing a light-sensitive algae protein into the eye. This new study manipulates existing proteins that our brains normally use to transmit information between neurons, and makes them light sensitive.
The researchers focused on several light-sensitive proteins, each with its own unique properties that could be fine-tuned to meet researchers’ specific needs. One such engineered protein, LiGluR (Light Activated Glutamate Receptor), can turn neuronal activity on and off upon illumination with specific wavelengths of light. There are many glutamate receptors in the human brain, but they are not normally light sensitive.
“Our approach was to build on these initial studies, to ‘re-engineer nature,’ by solving a deficit with engineered light-sensitive proteins,” said Natalia Caporale, PhD, at the University of California Berkeley, the study’s first author. “This approach could prove to be a viable therapeutic option for people who have lost significant vision and are in the late stages of retinal degeneration,” she said.
Compared with naturally occurring photosensitive proteins, LiGluR can initiate larger and longer-lasting responses in neurons, making it a promising candidate for treatments intended to restore vision.
“Basic neuroscience research has formed the basis for significant progress in treating eye disease,” said press conference moderator Rachel O. L. Wong, PhD, of the University of Washington, an expert on visual system development. “These studies would not be possible without technological advances and basic science research that continues to explain the normal function and development of the visual system,” Wong said.
Retinitis pigmentosa and age-related macular degeneration destroy the light-sensitive nerve cells in the retina, leading to blindness. In all, vision loss and eye disease affect 3.6 million Americans and cost the United States $68 billion each year.
Illustration: Microsoft clipart.
Society for Neuroscience Press Release (10/20/09)
Science Daily (10/21/09)
Abstract (Presented at Neuroscience 2009, the annual meeting of the Society for Neuroscience. Scientific Presentation: Wednesday, Oct. 21, 3:15–3:30 p.m., Room N426)