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Over the past three decades, scientists have looked to molecular biology and genetics to shed light on the complex interactions between the eyes and brain that give humans the ability to see and make sense of our surroundings. According to Johns Hopkins University researchers, genes, proteins and photoreceptors in the eyes hold the key to new ways of preventing and treating of potentially blinding diseases such as diabetic retinopathy (damage to the blood vessels in the retina—the light-sensitive layer at the back of the eye) and age-related macular degeneration (progressive damage to the central and most vital area of the retina, resulting in gradual loss of vision).
The pair—neuroscientist King-Wai Yau and microbiologist Jeremy Nathans—were recently awarded a $1.36-million (1-million-euro) prize by Portugal's philanthropic Champalimaud Foundation to continue their research in this field.
"For a long time, it wasn't clear the role that proteins played in the eye," says Yau, 59. The retina's receptors absorb light and trigger an electric signal that goes through the retina and on to the brain, providing it with the information needed for us to see images. Yau and his team are trying to determine the steps that take place between the absorption of light and the creation of that electric signal and how mutated or defective proteins may interfere with that process.
Yau also studies hereditary blinding diseases that affect the eye's rod and cone photoreceptor cells: specifically, why some blind people who do not have functioning rods and cones can still sense light and remain synchronized to day–night cycles.
"Our work has been to study how light triggers vision," he says. "The brain uses electrical signals to interpret light signals. Our lab is interested in the events that take place after the pigment has absorbed light."
Although they generally work independently, Yau and Nathans have collaborated to research mutated proteins found in the eyes of patients with early onset retinal degenerative disease that causes progressive vision loss.
Nathans, 50, has spent the past 25 years studying the retina, in particular trying to better understand the function of visual pigments—which are located in the retina's rods and cones —and how mutations in pigment genes can affect proteins in the eyes and lead to certain retinal diseases. "Our approach has been that of a molecular geneticist," he says "We're interested in analyzing the genes that encode the eye's proteins. It's very much a reductionist approach."
In 2006 Nathans and Gerald Jacobs, a psychologist at the University of California, Santa Barbara, reported in Science that they had successfully trained mice, genetically altered to have a full complement of photoreceptors (cells with a light-sensing protein pigment), to distinguish differences in shades of color that normal mice would not detect. When Nathans began researching color blindness in 1981, it was already clear that color-vision anomalies were passed down from parents to children and that there were different kinds of color blindness. His contribution was to attribute variations in color vision to the genes that encode the eye's light-sensing proteins. "Variation in those genes is," he says, "responsible for differences in color vision."
Nathans says the Champalimaud award will help fund research into the effect of different drugs on eye movement and vision, including those used to treat psychiatric and neurological disorders. "This knowledge could, in turn, lead to a better understanding of the central nervous system and how different drugs affect it," he says. "It's using the visual system in the service of pharmacology."
Champalimaud in January opened its Center for Translation Eye Research (C-TRACER). The center is known for using eye stem cells from living adults to grow new cells that are then implanted into damaged eyes to restore normal function. Champalimaud funded C-TRACER in an effort to prevent and treat vision-related disease and illness in Portugal and throughout the developing world.
The four-year-old foundation earlier this week broke ground on the construction of its the Champalimaud Center for the Unknown, a 645,800-square-foot (60,000-square-meter) Lisbon research center slated to open in October 2010 and focus on neuroscience and cancer research.