UNLV lab using African clawed frogs to unlock the secrets of human eye repair

Editor's note: Este artículo está traducido al español.

Regeneration has long been the stuff of science fiction. At UNLV, researchers are now studying frogs that can regrow their eyes in days — work that could bring that idea closer to reality for human patients.

Leading that effort is Kelly Ai-Sun Tseng, a professor in UNLV’s School of Life Sciences, whose lab is focused on understanding how natural regeneration works at a fundamental level. By studying species like the African clawed frog, Tseng and her team aim to identify the biological processes behind tissue repair and apply those findings to mammalian studies — with the long-term goal of developing therapies that could help restore vision in humans.

“We need to understand the fundamental processes of how natural regeneration occurs and … can use this knowledge to translate that into mammalian studies, and then hopefully to human therapeutics to promote regeneration and repair,” Tseng said.

Tseng came to UNLV in 2012 and is leading the charge on developing the region’s first laboratory program dedicated to research on cell regeneration.

Her past experience includes studying tadpoles’ ability to regrow their tails and what signals trigger regeneration.

Humans lack the ability to regenerate, but various bug and animal species — like worms, lizards, zebrafish, axolotl and the Xenopus laevis, or African clawed frog — regrow body parts across all stages of their lives .

The African clawed frog is an aquatic species native to parts of Africa, where they prefer to spend their time feeding and reproducing in stagnant waters.

Males weigh about 2 ounces and are 2 to 2.5 inches long, while females weigh about 7 ounces and are 4 to 4.5 inches long, according to the Smithsonian’s National Zoo and Conservation Biology Institute.

These frogs are considered a classic biomedical research species due to their genetic similarity to humans, and they serve as an established model for their regenerative abilities, Tseng said.

As larvae, the frogs can regenerate arms and legs, parts of their brain and even their optic nerves all the way through adulthood.

After moving to Las Vegas from Cambridge, Mass., where she earned her doctorate at Harvard University, Tseng wanted to continue her postdoctoral research on whether different organs can be stimulated with similar biological signals to regenerate.

That eventually led Tseng and her teams to look at the eye specifically, which “is a very important organ,” but “also very easily accessible and, in frogs, a lot already is known about how the eye normally develops,” Tseng said.

When initial observations found that frog larvae can regrow their eyes, most of Tseng’s time in the laboratory was spent documenting how they regenerate to understand the biological mechanisms of the cell.

It only took about five days for the eye to grow back — indistinguishable from its original, uninjured eye, said Tseng.

To Tseng’s knowledge, the UNLV laboratory is the first to study this eye regeneration model — a phenomenon Tseng’s researchers at UNLV observed, characterized and established.

“We have eyeglasses that help us see better, and then we have cataract surgeries that really help us see better, but one of the things we can’t do is regenerate our eyes if they get damaged, but they’re working on it,” UNLV Interim President Chris Heavey said of the project. “Amazing, (the) next generation of evolution or innovations that will drive human wellness.”

A tank with four African clawed frogs sits on a table within the Tseng Laboratory, surrounded by large models of eyes, informational posters, microscopes and various frog stickers, plushies, keychains and magnets.

The animals have been cared for by Tseng and her team of graduate and undergraduate researchers, like Jose Guerra, 23, who graduated from UNLV in the winter; second-year doctoral student Madison Frederick, 26; and Belen Gutierrez, 24, a third-year doctoral student.

Guerra and Gutierrez joined Tseng’s laboratory team as undergraduates at UNLV, with Guerra looking to make a difference in the world through research while Gutierrez grew up with an interest in the field of regeneration.

Frederick joined two years ago when she began her doctoral studies at UNLV and found Tseng’s program — which matched with Frederick’s previous experience studying neurodegenerative diseases.

The three students work on various projects within the laboratory that all relate back to the four-legged amphibians.

Guerra is becoming a pioneer in an emerging field at the intersection of biology and quantum physics by studying how quantum effects — like magnetic fields — can affect regeneration and tissue growth.

Identifying the types of stem cells that are able to regenerate is Frederick’s job, which she does using special fluorescent proteins, a method she said “is really interesting and such a strength of our model.”

Gutierrez uses micro-CT scanning to produce 3D renderings of the African clawed frogs’ eyes so she can analyze the structure and how those are affected by the regeneration process. She also works with computer modeling systems to produce similar images that help the researchers get a better view of the eye structure and its form throughout the regeneration process.

Tseng explained that scientists must first understand the fundamental process of how natural regeneration occurs. Then, she said, they can begin developing regenerative therapies for humans. The long-term goal is translating their current research into mammalian studies and, eventually, human therapeutics.

But it’s all starting with identifying stem cells driving regeneration and understanding molecular properties and how they impact other tissues.

For the students, the experience is also a way to broaden their horizons and represent UNLV.

The three students and others who have worked under Tseng have attended conferences, presented their research, networked at conferences outside of UNLV and won awards for their work.

Gutierrez said she wasn’t told in high school that doing research was a viable career move and didn’t think she’d be studying frogs in her future. But she loves it so much that she’s decided to stay as long as she can.

Guerra, who said “it’s really cool to be on the frontier of science,” plans to pursue a graduate degree at UNLV, as well, and continue working with Tseng.

“I feel really grateful just to be in graduate school,” Frederick said. “I really love that our research has the potential to have a lot of impact, like, we’re studying something that can really make a difference in people’s lives, and that we’re studying something so novel. Our lab’s the first to characterize this, so every day you kind of get to see something that maybe no one’s seen before, and that’s such a really cool opportunity to have.”