New breakthroughs in understanding blindness being made at UNH

Rick Cote and Michael Irwin look at a model of the activated complex of the enzyme PDE6 dimer.

DURHAM — Researchers at the University of New Hampshire are working to better understand the human eye with the hope that they can some day help people avoid certain types of blindness.

Scientists there recently reported the first structural model for a key enzyme and the activating protein that can play a role in some genetically inherited eye diseases such as retinitis pigmentosa and night blindness.

Retinitis pigmentosa is one of the most common forms of inherited retinal degeneration and involves the progressive loss of rod photoreceptors in the back of the eye. That is followed by the loss of cone photoreceptor cells and can lead to night blindness.

Rick Cote is the director of the Center of Integrated Biomedical and Bioengineering Research at UNH, which is funded by a five-year, $10 million grant from the National Institutes of Health. He said there has been substantial research involving photoreceptor phosphodiesterase 6 (PDE6) in the past, but defining atomic-level models is important to developing new therapeutic interventions.

Current medical treatment for such genetically inherited retina diseases include gene therapy or drugs meant to inhibit the disease process, but they are not always successful.

Cote said technological advances over the course of his 35-year career have helped researchers get to this point.

“In this particular case, we’re bringing together chemists and biologists to share their individual expertise to address a particular problem,” Cote said. “And the problem here is to use a number of tools to purify proteins but then ultimately to determine the structure of the protein at the atomic level, which requires techniques that go outside the realm of biology and enter into the realm of chemistry.”

Michael Irwin, a doctoral student from Townsend, Mass., was the lead author of the researchers’ study, which was published in the Journal of Biological Chemistry.

“We went through a very long stretch where virtually nothing was known about the structure of PDE6 and with this most recent work, and some of the work before, it feels like we’re going from a period of where we knew almost nothing to getting to a point where we’ll be able to visualize the activation and deactivation of PDE6, which is a huge step forward from even a couple of years ago,” Irwin said.

The research was funded by the National Eye Institute, the National Institute of General Medical Sciences, the National Institute of Child Health and Human Development, the National Science Foundation, and the UNH Research Office, according to a press release issued on Monday.

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