UIHC study aims to understand genes that cause blindness

A team of UI researchers are using gene therapy on mice in the hopes to cure human blindness in the future.

University+of+Iowa+Hospitals+and+Clinics+as+seen+on+Sept.+17%2C+2018.+

Katie Goodale

University of Iowa Hospitals and Clinics as seen on Sept. 17, 2018.

Charles Peckman, News Reporter

A small trough of water, a maze, and a very determined mouse — although this may sound like the setup for a bad joke, these simple “ingredients” are at the core of a groundbreaking University of Iowa Hospitals & Clinics study that could help cure blindness.

In an effort to regenerate nerve structures in the eye disrupted by gene mutation, a team of researchers led by UI Professor Sheila Baker is using gene therapy on mice with the hopes of someday transferring the therapy to blind human patients.

Baker said the study is particularly concerned with synaptic development, which takes into consideration how photoreceptor cells — the specialized part of the eye that senses light — pass information to the rest of the brain. In someone who experiences vision loss or blindness, this information is subdued or in some cases, nonexistent.

“All neurotransmitters work in the same way in that they pass along information to different parts of the brain, but it’s sort of like ice cream flavors — they can be grouped into different zones, different flavors — but their core functions are the same,” Baker said. “The real burning question for this field becomes, how do you make a synapse between A and B but not A and D?”

Although the brain contains different neurotransmitters — some regulating mood, alertness, and anxiety, for example — Baker said there are advantages to studying areas of the brain that affect vision.

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“The retina is a part of the brain that is organized in a very simple way,” she said. “The exact pairing of two neurons doesn’t occur anywhere else in the brain, so we’re trying to figure out how that connection is different. Anybody who studies synapses wants to know what’s special about their favorite synapse.”

In the retina, Baker and her team are focusing on the CACNA1F gene. While she said the various names given to genes can often be difficult to remember, their functions are typically easy to explain — CACNA1F facilitates communication between cells, but more importantly, has a “Velcro effect” that can reach across the synapse and perform repairs.

Research specialist Joseph Laird, who works with Baker on the study, said he is astonished with the results garnered thus far — when a blind mouse without the CACNA1F gene undergoes therapy to repair the retina, its ability to complete a water maze increases greatly.

“Normal, healthy mice can swim across 4 feet of water in less than two seconds,” Laird said. “Mice are great swimmers — they just don’t like being wet. Our experiments show that when we actually start to perform synaptic rewiring and drug trials, the mouse is able to complete the task in a suitable amount of time.”

Baker said there is a reason the study is being conducted on mice. As of right now, there are too many genetic manipulations to rule out adverse effects on humans. But soon, she said, the research could be used to help cure blindness in humans.

“We’re excited, but this is just a steppingstone,” Laird said. “This is the first step of a marathon where we’re trying to figure out how we can incorporate this [gene therapy] and make it better.”

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